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46 CFR 54.25-20 - Low temperature operation-ferritic steels with properties enhanced by heat treatment (modifies...
Code of Federal Regulations, 2011 CFR
...steels with properties enhanced by heat treatment (modifies UHT-5...Construction With Carbon, Alloy, and Heat Treated Steels ¦ 54.25-20...steels with properties enhanced by heat treatment (modifies UHT-5...service temperature shall not be colder than ?320 ░F. Service...
Correlation between thermal and mechanical properties of hardened steel treated by nitriding process
NASA Astrophysics Data System (ADS)
Ghrib, T.; Yacoubi, N.
In this work we have studied the nitriding effect for the 42CrMo4 steel on the evolution of their thermal and mechanical properties. The thermal properties are determined by the "Photothermal Deflection technique" method. It was shown that the thermal conductivity as well as the thermal diffusivity decreases if the nitrogen fraction in steel increases conversely the microhardness increases with the growth of the nitrogen rate. After, we have correlated the thermal and mechanical properties with an empirical equation that permits to determine the microhardness without its measure.
Modulation of dry tribological property of stainless steel by femtosecond laser surface texturing
NASA Astrophysics Data System (ADS)
Wang, Zhuo; Zhao, Quanzhong; Wang, Chengwei; Zhang, Yang
We reported on the modification of tribological properties of stainless steel by femtosecond laser surface microstructuring. Regular arranged micro-grooved textures with different spacing were produced on the AISI 304L steel surfaces by an 800-nm femtosecond laser. The tribological properties of smooth surface and textured surface were investigated by carrying out reciprocating ball-on-flat tests against Al2O3 ceramic balls under dry friction. Results show that the spacing of micro-grooves had a significant impact on friction coefficient of textured surfaces. Furthermore, the wear behaviors of smooth and textured surface were also investigated. Femtosecond laser surface texturing had a marked potential for modulating friction and wear properties if the micro-grooves were distributed in an appropriate manner.
Effect of charging energy on droplet diameters and properties of high-carbon steel coatings sprayed by wire explosion spraying
Qing Li; Qiu-zhi Song; Jian-zhong Wang; Ying-xian Duo
The purpose of this study is to investigate the effect of charging energy on droplet diameters and the properties of high-carbon steel coatings sprayed by wire explosion spraying. With different charging energies, droplets were collected when high-carbon steel wire explosion occurred, and the coatings were sprayed on aluminum alloy substrates. Droplet diameter distributions were obtained by using a Laser Particle
Frication Property of Mo-Cr-Infiltrated Steel Layer by Plasma Surface Metallurgy
NASA Astrophysics Data System (ADS)
Xu, Jinyong; Kang, Zhicheng; Liu, Yanping; Wang, Jianzhong; Gao, Yuan; Xu, Zhong
Introduced in this article is the technique to acquire a high performance strengthened layer on carbon steel samples, namely, plasma alloying on the surface of Q235 steel and heat treatment technology. With this technique the alloying elements of Mo, Cr, and C can be obtained on the surface of Q235 steel samples. The content of the constituent elements is approximately up to high speed steels (HSS). The surface property required for the HSS after hardening and low tempering is attained. In the test, the alloying elements Mo and Cr were penetrated into the Q235 steel samples by glow discharge sputtering so that the content of the alloyed layer on the surface of the Q235 steel samples was about 20% Mo and 10% Cr. Two kinds of experiments were conducted. One was to carry out ultra-saturated carburization. The alloyed layer's composition was similar to molybdenum HSS with surface carburizing of more than 2.0%. The carbides of the alloyed layer were compact, uniform and disperse without a coarse eutectic ledeburite structure. The another was ion nitriding after the alloying elements of Mo and Cr were penetrated. The first process included hardening with low tempering and hardening with cryogenic treatment for 2 hr and low tempering. The second one was ion nitriding only. It was found that the surface hardness after cryogenic treatment is up to 1600 HV, much higher than that without cryogenic treatment. The abrasion test results indicate that, without the penetrated alloy elements Mo and Cr and without cryogenic treatment and ion nitriding, the friction coefficient is lower by one order of magnitude. The change in relative resistance is similar to the change in the friction coefficient, but without a proportional relationship.
Surface properties of low alloy steel treated by plasma nitrocarburizing prior to laser quenching process
NASA Astrophysics Data System (ADS)
Wang, Y. X.; Yan, M. F.; Li, B.; Guo, L. X.; Zhang, C. S.; Zhang, Y. X.; Bai, B.; Chen, L.; Long, Z.; Li, R. W.
Laser quenching (LQ) technique is used as a part of duplex treatments to improve the thickness and hardness of the surface layers of steels. The present study is to investigate the surface properties of low alloy steel treated by plasma nitrocarburizing (PNC) prior to a laser quenching process (PNC+LQ). The microstructure and properties of PNC+LQ layer determined are compared with those obtained by PNC and LQ processes. OM, XRD, SEM and EDS analyses are utilized for microstructure observation, phases identification, morphology observation and chemical composition detection, respectively. Microhardness tester and pin-on-disc tribometer are used to investigate the mechanical properties of the modified layers. Laser quenching of plasma nitrocarburized (PNC+LQ) steel results in much improved thickness and hardness of the modified layer in comparison with the PNC or LQ treated specimens. The mechanism is that the introduction of trace of nitrogen decreases the eutectoid point, that is, the transformation hardened region is enlarged under the same temperature distribution. Moreover, the layer treated by PNC+LQ process exhibits enhanced wear resistance, due to the lubrication effect and optimized impact toughness, which is contributed to the formation of oxide film consisting of low nitrogen compound (FeN0.076) and iron oxidation (mainly of Fe3O4).
Improvement of mechanical properties on metastable stainless steels by reversion heat treatments
NASA Astrophysics Data System (ADS)
Mateo, A.; Zapata, A.; Fargas, G.
AISI 301LN is a metastable austenitic stainless steel that offers an excellent combination of high strength and ductility. This stainless grade is currently used in applications where severe forming operations are required, such as automotive bodies. When these metastable steels are plastically deformed at room temperature, for example by cold rolling, austenite transforms to martensite and, as a result, yield strength increases but ductility is reduced. Grain refinement is the only method that allows improving strength and ductility simultaneously. Several researchers have demonstrated that fine grain AISI 301LN can be obtained by heat treatment after cold rolling. This heat treatment is called reversion because it provokes the reversion of strain induced martensite to austenite. In the present work, sheets of AISI 301LN previously subjected to 20% of cold rolling reduction were treated and a refined grain austenitic microstructure was obtained. Mechanical properties, including fatigue limit, were determined and compared with those corresponding to the steel both before and after the cold rolling.
Fatigue properties of a biomedical 316L steel processed by surface mechanical attrition
NASA Astrophysics Data System (ADS)
Sun, Z.; Chemkhi, M.; Kanoute, P.; Retraint, D.
This work deals with the influence of surface mechanical attrition treatment (SMAT) on fatigue properties of a medical grade 316L stainless steel. Metallurgical parameters governed by SMAT such as micro-hardness and nanocrystalline layer are characterized using different techniques. Low cycle fatigue tests are performed to investigate the fatigue properties of untreated and SMAT-processed samples. The results show that the stress amplitude of SMAT- processed samples with two different treatment intensities is significantly enhanced compared to untreated samples, while the fatigue strength represented by the number of cycles to failure is not improved in the investigated strain range. The enhancement in the stress amplitude of treated samples can be attributed to the influence of the SMAT affected layer.
Anisotropic mechanical properties of the MA956 ODS steel characterized by the small punch testing technique
NASA Astrophysics Data System (ADS)
Turba, K.; Hurst, R. C.; Hõhner, P.
The small punch testing technique was used to assess both creep and fracture properties of the MA956 oxide dispersion strengthened ferritic steel. The anisotropy in mechanical properties was addressed, as well as the alloy's susceptibility to thermal embrittlement. Strong anisotropy was found in the material's creep resistance at 725 ░C for longer rupture times. Anisotropic behavior was also observed for the ductile-brittle transition temperature (DBTT). The origin of the anisotropy can be related to the strongly directional microstructure which enables a large amount of intergranular cracking during straining at both high and low temperatures. The DBTT of the alloy is very high, and can be further increased by at least 200 ░C after 1000 h of ageing at 475 ░C, due to the formation of the Cr-rich ?' phase. The particularly high susceptibility of the MA956 to thermal embrittlement is mainly a consequence of its high chromium content.
Properties and potential for application of steel reinforced polymer and steel reinforced grout composites
X. Huang; V. Birman; A. Nanni; G. Tunis
The paper introduces steel reinforced polymer (SRP) and steel reinforced grout (SRG) composites that are considered for application in civil engineering for bridge and concrete buildings upgrade. These composites consist of steel cords formed by interwoven steel wires embedded within a polymer resin or cementitious grout matrix. The properties of SRP are evaluated experimentally and compared to micromechanical equations to
Changes of inclusion, texture and magnetic property of non-oriented Si steel treated by Ca alloy
NASA Astrophysics Data System (ADS)
Lv, X.; Zhang, F.; Chen, X.
Based on the industrial production of non-oriented Si steel, Ca treatment by Ca alloy adding during the RH refining process was studied. The changes of inclusion, crystal texture and microstructure, and its effect on magnetic properties of final steel sheets were analyzed. The results showed that, in present work, Ca treatment can improve the texture proportion of {110} and {111} significantly, and the formation of MnS and AlN inclusions were restrained. Meanwhile, the recrystallization effects of hot rolled strip get bad and the fiber structure enhanced obviously. The grain size of finished steel sheets increased as the increase of Ca alloy adding amount quickly, and then decreased. Compared with the non-Ca treatment charge, the numbers of inclusions whose size below 1.0?m will decrease by 68.06%, 87.50% and 94.94%, the texture proportion of {110} and {111} was 30.3%, 39.1%, 17.6% and 2.8%, 5.5%, 20.6%, while the correspondent Ca alloy adding amount is 0.67 kg/t steel, 1.00 kg/t steel and 1.67 kg/t steel, respectively. In addition, the core loss gradually decreases to a stable level as the increasing of Ca added, and the magnetic induction decreases quickly after slow increasing, respectively. The optimal Ca treatment mode depends on the chemical compositions of steel grades.
Properties of bearing steel extruded from powder obtained by spraying of molten production chips
A. Shalak; V. S. Ivanov; M. Seletska; P. Veles
Bearing steel bars may be produced by extrusion of powder produced by spraying of molten production chips with nitrogen. This makes it possible to introduce recycling of metal scrap in the production plant.
Increasing the protective and decorative properties of carbon steel parts by chemicothermal treatment
A. A. Voronko; V. I. Dzyuba; S. V. Koldina
In the M. V. Frunze Scientific and Production Union a significant quantity of hardware (bolts, studs, screws, etc.) is produced from carbon steels. To impart decorative properties and also for protection from the corrosive action of production atmospheres and working media various galvanic coatings are applied to the hardware. However, a major disadvantage of the galvanic method is contamination of
Effect of surface nanocrystallization induced by fast multiple rotation rolling on mechanical properties of a low carbon steel
Pengfei Chui; Kangning Sun; Chang Sun; Chengge Wu; Hongyou Wang; Yan Zhao
Fast multiple rotation rolling (FMRR), a novel and efficient surface nanocrystallization technique, was used to fabricate a nanostructured layer in the surface of low carbon steel. The microstructure of the surface layer was characterized by transmission electron microscopy, optical microscope and scanning electron microscopy, and mechanical properties were investigated by microhardness measurements, tensile measurements and friction and wear tests. In
Study on microstructure and mechanical properties of 304 stainless steel joints by TIG, laser and laser TIG hybrid welding
Jun Yan; Ming Gao; Xiaoyan Zeng
This paper investigated the microstructure and mechanical properties of 304 stainless steel joints by tungsten inert gas (TIG) welding, laser welding and laser-TIG hybrid welding. The X-ray diffraction was used to analyze the phase composition, while the microscopy was conducted to study the microstructure characters of joints. Finally, tensile tests were performed and the fracture surfaces were analyzed. The results
Mechanical property and microstructural change by thermal aging of SCS14A cast duplex stainless steel
NASA Astrophysics Data System (ADS)
Yamada, Takuyo; Okano, Satoshi; Kuwano, Hisashi
The aging behavior, especially saturation, of JIS SCS14A cast duplex stainless steels was investigated on the basis of the mechanical properties and microstructural changes during accelerated aging at 350 ░C and 400 ░C. The aging behavior of the materials mainly proceeds via two stages. During the first stage, the generation and concentration of the iron-rich and chromium-enriched phase in ferrite occurs by phase decomposition. The first stage corresponds to aging times of up to 3000 h at 400 ░C. During the first stage, the ferrite hardness achieved is approximately 600 VHN, and the Charpy impact energy is almost saturated. During the second stage, the precipitated chromium-enriched phase aggregates and coarsens, and the G phase precipitation also occurs. The second stage corresponds to the aging times range of 3000-30 000 h at 400 ░C. During the second stage, the ferrite hardness achieved is about 800 VHN; however, further hardening exceeding 600 VHN does not influence the Charpy impact energy.
Microstructure and mechanical properties of hard carbon films prepared by heat treatment of a polymer on steel substrate
Xingbin Yan; Tao Xu; Xiaobo Wang; Huiwen Liu; Shengrong Yang
Hard carbon films were prepared on steel substrates by heat treatment of a polymer-poly(phenylcarbyne) at various temperatures in an Ar atmosphere. The influence of heat treatment temperature on the microstructure, surface roughness and mechanical properties of the resulting films was investigated by Raman spectroscopy, atomic force microscopy (AFM), nanoindenter, scratch and ball-on-disk sliding tests. The sp2 C fractions of the
Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel
Yimin Lin; Jian Lu; Liping Wang; Tao Xu; Qunji Xue
A plastic deformation surface layer with nanocrystalline grains was produced on AISI 321 austenitic stainless steel by means of surface mechanical attrition treatment (SMAT). Low-temperature nitriding of SMAT and un-SMAT AISI 321 stainless steel was carried out in pulsed-DC glow discharge. The effect of SMAT pretreatment on the microstructure and properties of the stainless steel were investigated using X-ray diffraction,
Surface property enhancement of Ni-free medical grade austenitic stainless steel by low-temperature plasma carburising
Joseph Buhagiar; Linmao Qian; Hanshan Dong
Based on the success of the feasibility study reported, the surface properties of low-temperature plasma carburised P558 Ni-free medical grade (ASTM F2581) austenitic stainless steel have been fully evaluated in terms of electrochemical corrosion, dry- and corrosion-wear and fretting-wear in Ringer's solution. Anodic polarization tests demonstrated that the precipitate-free S-phase generated by low-temperature plasma carburising at 500░C for 15h can
Residual stress and thermal properties of zirconia\\/metal (nickel, stainless steel 304) functionally graded materials fabricated by hot pressing
Yeon-Gil Jung; Sung-Churl Choi; Chang-Seob Oh; Un-Gyu Paik
To analyse the residual stress and the thermal properties of functionally graded materials (FGMs), disc-type tetragonal zirconia\\u000a polycrystal (TZP)\\/Ni- and TZP\\/stainless steel 304 (SUS304)-FGM were hot pressed, and compared with directly jointed materials\\u000a (DJMs). The continuous interface and the microstructure of FGMs were characterized by electron probe microanalysis, wavelength\\u000a dispersive spectrometry, optical microscopy and scanning electron microscopy. It has been
Mechanism of enhancement of the corrosion of steel by alternating currents and electrocatalytic properties of cycled steel surfaces
M. L. Mateo; T. Fernandez Otero; D. J. Schiffrin
The effect of potential cycling on the growth of oxide layers on steel is analysed. It is shown that the redox reactions in the oxide layers formed are diffusion controlled and it is proposed that the transport of OH- is the limiting step of growth. The relationship of these results to ac corrosion is discussed and it is shown that
Characterization of a boron alloyed 9Cr3W3CoVNbBN steel and further improvement of its high-temperature mechanical properties by thermomechanical treatments
NASA Astrophysics Data System (ADS)
Hollner, S.; Piozin, E.; Mayr, P.; Caļs, C.; Tourniķ, I.; Pineau, A.; Fournier, B.
In the framework of the development of Generation IV nuclear reactors and fusion nuclear reactors, materials with an improved high temperature (?650 ░C) mechanical strength are required for specific components. The 9-12% Cr martensitic steels are candidate for these applications. Previous works showed that the application of a thermomechanical treatment, including warm-rolling in metastable austenitic phase, to the commercial Grade 91 martensitic steel, allowed refining its microstructure, improving its precipitation state and its mechanical properties (hardness, tensile and creep properties). In the present paper, experimental steel called NPM, designed for good high-temperature creep resistance, is evaluated in terms of microstructure and mechanical properties, and compared to the G91 steel. Then the developed thermomechanical treatment is applied to this steel. Its microstructure is refined and its hardness and tensile properties are much better than the as-received NPM and therefore than the G91 steel. The cyclic softening effect still occurs for the optimized NPM, but this material once softened by cyclic loadings, still presents better creep properties than the as-received NPM steel, and even more than the commercial G91 steel.
The mechanical properties of H13 die steel repaired by a biomimetic laser technique
NASA Astrophysics Data System (ADS)
Cong, Dalong; Zhou, Hong; Yang, Miaoqiang; Zhang, Zhihui; Zhang, Peng; Meng, Chao; Wang, Chuanwei
The H13 steel specimens with cracks were repaired by pulsed laser welding with filler wire and the laser parameters were analyzed to obtain the weld without defects. Strengthening units with different spacing were fabricated to improve the tensile strength and thermal fatigue resistance of the weld by laser technique on the surfaces of specimens, that is, PS-1, PS-2 and PS-3 for tensile specimens and PS for thermal fatigue specimen. The results indicated that the units have a beneficial effect on improving the tensile strength and thermal fatigue resistance of welded components of H13 steel. The improvement can be attributed to the microstructure characteristics within the units and the spacing of adjacent units is a key factor which affects the strength of weld by biomimetic treatment.
Formation of structure and properties of composite bronzes reinforced by steel dendrites
NASA Astrophysics Data System (ADS)
Potekhin, B. A.; Ilyushin, V. V.; Khristolyubov, A. S.; Zhilyakov, A. Yu.
The investigation of experimental alloys of the BrZhNKA 9-4-1-1 type has shown the possibility of production of bronzes as antifriction alloys, in which, instead of brittle intermetallic compounds, steel dendrite-like inclusions of, e.g., steel N12K7Yu, are used. In these alloys, the phenomenon of the redistribution of alloying elements (Ni, Co, Al) between the matrix and dendrites in the process of heat treatments has been considered. The growth of these dendrites was found to occur in the solid state via the directional diffusion of Fe, Ni, and Co from the copper matrix to dendrites. This leads to the formation of a shell around them, which represents a substitutional solid solution of Cu, Ni, and Co in iron, e.g., with a composition of Fe6Cu3Ni2Co. On the whole, the mechanical, tribological, and engineering properties of such bronzes, e.g., BrZhNKA 9-4-1-1, are higher than those of the well-known antifriction bronzes BrO10 or BrAZhN 10-4-4.
Control of the wetting properties of an AISI 316L stainless steel surface by femtosecond laser-induced surface modification
NASA Astrophysics Data System (ADS)
Kam, D. H.; Bhattacharya, S.; Mazumder, J.
A simple and effective method without vacuum to control the wetting properties of AISI 316L stainless steel using femtosecond laser pulses at high repetition rate has been developed. Both hydrophilic and hydrophobic surfaces were formed by creating micro-conical structures on the surface with femtosecond laser irradiation in air. The scan speed was found to be an effective parameter in controlling micro-cone morphology, size and number densities and contact angles during surface wettability experiments. It was found during surface wettability experiments that the contact angle of water varied from 0░ (superhydrophilic) to 113░ on laser micro-cone textured surfaces depending on processing conditions. Additionally, a superhydrophobic AISI 316L stainless steel surface was created (contact angle ś150░) with a functionalized silane coating on already hydrophobic surface geometry.
Tribological properties of plasma nitrided stainless steel against SAE52100 steel under ionic liquid lubrication condition
Yanqiu Xia; Shijie Wang; Feng Zhou; Haizhong Wang; Yimin Lin; Tao Xu
1Cr18Ni9Ti stainless steel was modified by plasma nitriding. The phase composition of the plasma nitrided layer was examined by means of X-ray diffraction. The friction and wear properties of the modified and unmodified 1Cr18Ni9Ti stainless steel specimens sliding against SAE52100 steel under the lubrication of ionic liquid of 1-ethyl-3-hexylimidazolium hexafluorophosphate (L-P308) and poly ?-olefin (PAO) were investigated on an Optimol
Effect of substrates on microstructure and mechanical properties of nano-eutectic 1080 steel produced by aluminothermic reaction
La, Peiqing, E-mail: email@example.com; Li, Zhengning; Li, Cuiling; Hu, Sulei; Lu, Xuefeng; Wei, Yupeng; Wei, Fuan
Nano-eutectic bulk 1080 carbon steel was prepared on glass and copper substrates by an aluminothermic reaction casting. The microstructure of the steel was analyzed by an optical microscope, transmission electron microscopy, an electron probe micro-analyzer, a scanning electron microscope and X-ray diffraction. Results show that the microstructure of the steel consisted of a little cementite and lamellar eutectic pearlite. Average lamellar spacing of the pearlite prepared on copper and glass substrates was about 230 nm and 219 nm, respectively. Volume fraction of the pearlite of the two steels was about 95%. Hardness of the steel was about 229 and 270 HV. Tensile strength was about 610 and 641 MPa and tensile elongation was about 15% and 8%. Compressive strength was about 1043 and 1144 MPa. Compared with the steel prepared on copper substrate, the steel prepared on glass substrate had smaller lamellar spacing of the pearlite phase and higher strength, and low ductility due to the smaller spacing. - Highlights: Ģ 1080-carbon steels were successfully prepared by an aluminothermic reaction casting. Ģ Lamellar spacing of the nanoeutetic pearlite is less than 250 nm. Ģ The compressive strength of the steel is about 1144 MPa. Ģ The tensile ductility of the steel is about 15%.
A comparative study of the mechanical properties and the behavior of carbon and boron in stainless steel cladding tubes fabricated by PM HIP and traditional technologies
NASA Astrophysics Data System (ADS)
Shulga, A. V.
The ring tensile test method was optimized and successfully used to obtain precise data for specimens of the cladding tubes of AISI type 316 austenitic stainless steels and ferritic-martensitic stainless steel. The positive modifications in the tensile properties of the stainless steel cladding tubes fabricated by powder metallurgy and hot isostatic pressing of melt atomized powders (PM HIP) when compared with the cladding tubes produced by traditional technology were found. Presently, PM HIP is also used in the fabrication of oxide dispersion strengthened (ODS) ferritic-martensitic steels. The high degree of homogeneity of the distribution of carbon and boron as well the high dispersivity of the phase-structure elements in the specimens manufactured via PM HIP were determined by direct autoradiography methods. These results correlate well with the increase of the tensile properties of the specimens produced by PM HIP technology.
Estimation of mechanical properties of irradiated nuclear pressure vessel steel by use of subsized CT specimen and small punch specimen
X. Mao; H. Takahashi; T. Kodaira
This paper reports on the 2-1\\/4 Cr-1MŌ steel that has been selected as the material for the reactor pressure vessel (RPV) of a multipurpose experimental high temperature gas cooled reactor designed by JAERI. The 2-1\\/4 Cr-1MŌ steel has successful records for high temperature pressure vessels in the petrochemical industries and the ASME Code Case authorizes the use of the steel
Mechanical properties of articles formed from powder alloy steels
T. A. Pumpyanskaya; N. V. Krokhina; E. M. Fainshmidt
1.The plasticity and impact strength of articles formed from powder Ni-Mo-Cu steel using nickel and molybdenum oxides are two times higher than those attained when this same steel is alloyed with metallic powders of nickel and molybdenum.2.The improved mechanical properties of steels formed from partially alloyed iron powder using nickel and molybdenum oxides are explained by the uniformity of the
Iron and Steel- Properties and Applications
NSDL National Science Digital Library
Stoebe, Thomas G.
This document provides a learning module on iron and steel for use in materials education. The lesson examines the basic properties of iron and steel and includes discussions, demonstrations and suggested optional classroom activities. The materials can be covered in one to two class periods.
Effect of the Surface State of Steel on the Microstructure and Mechanical Properties of Dissimilar Metal Lap Joints of Aluminum and Steel by Friction Stir Welding
Y. C. Chen; K. Nakata
Friction stir lap joints of AC4C Al alloy (top sheet) and steel (zinc-coated steel, brushed finish steel, and mirror finish\\u000a steel) were produced when the friction stir welding tool did not touch the lower steel surface. For zinc coat steel, the strength\\u000a of joints could reach 97.7Āpct of that of steel; for brushed finish steel, the strength was 63.2Āpct of
The mechansims by which solute nitrogen affects phase transformations and mechanical properties of automotive dual-phase sheet steel
NASA Astrophysics Data System (ADS)
Brown, Tyson W.
Dual-phase steels have seen increased use in automotive applications in recent years, in order to meet the goals of weight reduction and occupant safety. Variations in nitrogen content that may be encountered in steel sourced from a basic oxygen furnace process compared to an electric arc furnace process require that dual-phase steel producers understand the ways that nitrogen affects processing and properties. In the current work, the distribution of nitrogen was investigated in a dual-phase steel with a base chemistry of 0.1 C, 2.0 Mn, 0.2 Cr, 0.2 Mo (wt pct) across a range of nitrogen contents (30-159 ppm) with Al (0.2 and 0.08 wt pct), and Ti (0.02 wt pct) additions used for precipitation control of nitrogen amounts. The distribution of nitrogen amongst trapping sites, including precipitates, grain boundaries, dislocations, and interstitial sites (away from other types of defects) was determined from a combination of electrolytic dissolution, internal friction, and three-dimensional atom probe tomography experiments. Various mechanisms by which different amounts and locations of nitrogen affect phase transformations and mechanical properties were identified from quantitative metallography, dilatometric measurement of phase transformations, tensile testing, and nanoindentation hardness testing. Results indicate nitrogen that is not precipitated with Ti or Al (free nitrogen) partitions to austenite (and thus martensite) during typical intercritical annealing treatments, and is mostly contained in Cottrell atmospheres in martensite. Due to the austenite stabilizing effect of nitrogen, the presence of free nitrogen during intercritical annealing leads to a higher austenite fraction in certain conditions. Thus, the presence of free nitrogen in a dual-phase microstructure will lead to an increase in tensile and yield strengths from both an increase in martensite fraction, and an increase in martensite hardness due to solid solution strengthening. Despite the presence of free nitrogen, no yield point elongation was detected in tensile stress-strain results, including after 80 ░C aging treatments. This was likely due to the partitioning of nitrogen, such that the ferritic regions of the microstructure contained less nitrogen than is required to saturate the high dislocation density in ferrite. Measured tensile and yield strength sensitivities to free nitrogen content range between 7 and 13 GPa/wt pct N.
Properties of steels used in petroleum engineering
Sorokin, G.M.; Bobrov, S.N.; Evdokimov, V.V.; Tsvetkov, Y.N.
This paper investigates the mechanical properties, local plastic deformation, and character of failure of D5KhN2MFASh and 16KhN3MASh steels after different heat treatments. The chemical analyses of these steels are shown in a table. An analysis of the geometry of type T drill bit roller cutter teeth of different diameters showed that the relative area of the tough core of the roller cutters in the most dangerous (from the point of view of failure) cross section for 93-151 mm diam. bits is 0.38-0.45. Taking into consideration the higher strength properties of D5KhN2MFASh steel, higher wear resistance and life of drill bits (type T) with roller cutters of this steel may be expected in comparison with the wear resistance of drill bits with standard roller cutters produced of 16KhN3MASh steel.
Mechanical properties of duplex layer formed on AISI 403 stainless steel by chromizing and boronizing treatment
Sang Yul Lee; Gwang Seok Kim; Bum-Suk Kim
In order to improve the high temperature performance of AISI 403 martensitic stainless steel, duplex surface treatment which combines the methods of pack cementation chromizing and boronizing was carried out. Specimens were chromized at 1100 ░C for 2 h and were subsequently boronized in a solid medium consisting of EKabor-III powders at 950 ░C for 9 h. The characteristics of
Influence of Deposition Conditions on Fatigue Properties of Martensitic Stainless Steel with Tin Film Coated by Arc Ion Plating Method
NASA Astrophysics Data System (ADS)
Fukui, Satoshi; Yonekura, Daisuke; Murakami, Ri-Ichi
The surface properties like roughness etc. strongly influence the fatigue strength of high-tensile steel. To investigate the effect of surface condition and TiN coating on the fatigue strength of high-strength steel, four-point bending fatigue tests were carried out for martensitic stainless steel with TiN film coated using arc ion plating (AIP) method. This study, using samples that had been polished under several size of grind particle, examines the influence of pre-coating treatment on fatigue properties. A 2-Ąm-thick TiN film was deposited onto the substrate under three kinds of polishing condition. The difference of the hardness originated in the residual stress or thin deformation layer where the difference of the size of grinding particle of the surface polishing. And it leads the transformation of the interface of the substrate and the TiN film and improves fatigue limit.
Wear and corrosion properties of a low carbon steel processed by means of SMAT followed by lower temperature chromizing treatment
Z. B. Wang; J. Lu; K. Lu
A duplex lower temperature chromizing treatment at 600Ā░C for 120Āmin followed by 860Ā░C for 90Āmin was performed on a low carbon steel plate with a nanostructured surface layer, induced by surface mechanical attrition treatment (SMAT) [Z.B. Wang, J. Lu, K. Lu, Acta Mater. 53 (2005) 2081]. Microhardness, wear and corrosion resistances of the chromized SMAT sample were measured, in comparison
Enhancement in corrosion barrier properties of polyurethane films on steel by embedding MgO nanoparticles.
Nguyen, Van Quyet; Lee, Hee-Dong; Jung, Hun Seok; Tai, Weon Pil; Lee, Jae-Shin
The effect of nanosized MgO loading on the corrosion barrier characteristics of polyurethane (PU) films on mild steel has been investigated. It was found that small amount of MgO loading even as low as 0.03 vol% significantly improved the corrosion retardation ability of PU films. Both the enhanced adhesion strength and the formation of chemically strong -NCO radicals between nano-MgO and PU matrix seem to be responsible for the enhancement. PMID:21456182
Mechanical Properties, Thermal Stability and Radiation Damage of Ferritic Steels Processed by Thermal Mechanical TreatmentsĀ
Song, Miao
'T Tempered Martensite ?'AT Auto-tempered Martensite ?B Bainitic Ferrite M/A Martensite/Austenite Constituent ? Retained Austenite ?-C Epsilon Carbide ? Cementite ?y/ ?0.2 Yield Strength ?UTS Ultimate Tensile Strength G Shear Modulus... ........................................................................... 49 3.2.1 Additional nomenclature for T91 ................................................................. 49 3.2.2 Water quenching of T91 steels ..................................................................... 49 3.3 ?-carbides in the water...
Microstructure characteristics and mechanical property of aluminum alloy\\/stainless steel lap joints fabricated by MIG welding¢brazing process
Hongtao Zhang; Jiakun Liu
Lap joints of aluminum alloy 2B50 and stainless steel 1Cr18Ni9Ti were welded by MIG welding¢brazing method with 4043 Al¢Si filler metal. The effect of aluminizing coating and galvanized zinc coating on fusion metal spreadability were studied. The aluminized coating had limited effect to promote weld surface appearance and obvious micro-cracks were found between the compound layer and the steel side.
Thermophysical property sensitivity effects in steel solidification
NASA Technical Reports Server (NTRS)
Overfelt, Tony
The simulation of advanced solidification processes via digital computer techniques has gained widespread acceptance during the last decade or so. Models today can predict transient temperature fields, fluid flow fields, important microstructural parameters, and potential defects in castings. However, the lack of accurate thermophysical property data on important industrial alloys threatens to limit the ability of manufacturers to fully capitalize on the technology's benefits. A study of the sensitivity of one such numerical model of a steel plate casting to imposed variations in the data utilized for the thermal conductivity, specific heat, density, and heat of fusion is described. The sensitivity of the data's variability is characterized by its effects on the net solidification time of various points along the centerline of the plate casting. Recommendations for property measurements are given and the implications of data uncertainty for modelers are discussed.
Improvement of mechanical and tribological properties in steel surfaces by using titanium-aluminum/titanium-aluminum nitride multilayered system
NASA Astrophysics Data System (ADS)
Ipaz, L.; Caicedo, J. C.; Esteve, J.; Espinoza-Beltran, F. J.; Zambrano, G.
Improvement of mechanical and tribological properties on AISI D3 steel surfaces coated with [Ti-Al/Ti-Al-N]n multilayer systems deposited in various bilayer periods (?) via magnetron co-sputtering pulsed d.c. method, from a metallic binary target; has been studied in this work exhaustively. The multilayer coatings were characterized in terms of structural, chemical, morphological, mechanical and tribological properties by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy, nanoindentation, pin-on-disc and scratch tests, respectively. The failure mode mechanisms were studied by optical microscopy. Results from X-ray diffraction analysis revealed that the crystal structure of TiAl/TiAlN multilayer coatings has a tetragonal and FCC NaCl-type lattice structures for Ti-Al and Ti-Al-N, respectively, i.e., it was found to be non-isostructural multilayers. An enhancement of both hardness and elastic modulus up to 29 GPa and 260 GPa, respectively, was observed as the bilayer periods (?) in the coatings were decreased. The sample with a bilayer period (?) of 25 nm and bilayer number n = 100 showed the lowest friction coefficient (?0.28) and the highest critical load (45 N), corresponding to 2.7 and 1.5 times better than those values for the coating deposited with n = 1, respectively. These results indicate an enhancement of mechanical, tribological and adhesion properties, comparing to the [Ti-Al/Ti-Al-N]n multilayer systems with 1 bilayer at 26%, 63% and 33%, respectively. This enhancement in hardness and toughness for multilayer coatings could be attributed to the different mechanisms for layer formation with nanometric thickness such as the novel Ti-Al/Ti-Al-N effect and the number of interfaces that act as obstacles for the crack deflection and dissipation of crack energy.
Properties of cryogenically worked metals. [stainless steels
NASA Technical Reports Server (NTRS)
Schwartzberg, F. R.; Kiefer, T. F.
A program was conducted to determine whether the mechanical properties of cryogenically worked 17-7PH stainless steel are suitable for service from ambient to cryogenic temperatures. It was determined that the stress corrosion resistance of the cryo-worked material is quite adequate for structural service. The tensile properties and fracture toughness at room temperature were comparable to titanium alloy 6Al-4V. However, at cryogenic temperatures, the properties were not sufficient to recommend consideration for structural service.
Study of the effect of nano-sized precipitates on the mechanical properties of boron-added low-carbon steels by neutron scattering techniques
Seong, B. S.; Cho, Y. R.; Shin, E. J.; Kim, S. I.; Choi, S.-H.; Kim, H. R.; Kim, Y. J.
Small-angle neutron scattering (SANS) and neutron powder diffraction (ND) techniques were used to study quantitatively the effect of nano-sized precipitates and boron addition on the mechanical properties of low-carbon steels. SANS was used to evaluate nano-sized precipitates, smaller than about 600?┼ in diameter, and ND was used to determine the weight fraction of the cementite precipitates. Fine core¢shell structured spherical precipitates with an average radius of ~50?┼, such as MnS and/or CuS, surrounded by BN layers were observed in the boron-added (BA) low-carbon steels; fine spherical precipitates with an average radius of ~48?┼ were mainly observed in the boron-free (BF) low-carbon steels. In the BA steels, the number of boron precipitates, such as BN, Fe3(C,B) and MnS, surrounded by BN layers increased drastically at higher hot-rolling temperatures. The volume fraction of the fine precipitates of the BA steels was higher than that of the BF steels; this difference is related to the rapid growth of the BN layers on the MnS and CuS precipitates. Boron addition to low-carbon steels resulted in a reduction in strength and an improvement in elongation; this behaviour is related to the reduction of the solute carbon and the nitrogen contents in the ferrite matrix caused by the precipitation of BN, as well by the increase in the volume fraction of the cementites. PMID:19461851
Thermal models of ASRM case steel properties
Rea, S.N.; Cheng, N.; Mohn, W.R. (Aerojet, Iuka, MS (United States) Babcock Wilcox Research Center, Alliance, OH (United States))
High performance alloy steels require many heat treatment steps in order to realize their potential. These heat treatments create residual stresses and deformations which must be taken into account when designing forgings to insure final machined part tolerances can be met. These residuals can be computed with reasonable precision through thermal stress modeling, provided detailed material property data are known. This paper discusses thermophysical properties determined for HP 9-4-30 steel. A particularly interesting feature of this material is specific heat hysteresis, in which rapid quenches from the austenitic region follow a different c-T curve than do slow equilibrium temperature changes. This hysteresis was determined through a novel combination of thermal modeling with experimental data. The specific heat behavior of HP 9-4-30 should be characteristic of similar alloy steels which undergo phase changes, and this hysteresis needs to be included in thermal models of high temperature quenches. 8 refs.
Mechanical properties and pitting corrosion behaviour of 316L stainless steel parts obtained by a modified metal injection moulding process
L Castro; S Merino; B Levenfeld; A Vßrez; J. M Torralba
Stainless steel AISI 316L parts have been obtained by a modified metal injection moulding (MIM) process using two different thermosetting polymers: commercial acrylic resin and cyclohexyl methacrylate (CHMA). The first resin polymerises at 90░C while the later cures between 20 and 80░C. Different mixtures of metal and polymer were investigated and the optimum one was 60vol.% of metal, for both
X-ray attenuation properties of stainless steel (u)
Wang, Lily L [Los Alamos National Laboratory; Berry, Phillip C [Los Alamos National Laboratory
Stainless steel vessels are used to enclose solid materials for studying x-ray radiolysis that involves gas release from the materials. Commercially available stainless steel components are easily adapted to form a static or a dynamic condition to monitor the gas evolved from the solid materials during and after the x-ray irradiation. Experimental data published on the x-ray attenuation properties of stainless steel, however, are very scarce, especially over a wide range of x-ray energies. The objective of this work was to obtain experimental data that will be used to determine how a poly-energetic x-ray beam is attenuated by the stainless steel container wall. The data will also be used in conjunction with MCNP (Monte Carlos Nuclear Particle) modeling to develop an accurate method for determining energy absorbed in known solid samples contained in stainless steel vessels. In this study, experiments to measure the attenuation properties of stainless steel were performed for a range of bremsstrahlung x-ray beams with a maximum energy ranging from 150 keV to 10 MeV. Bremsstrahlung x-ray beams of these energies are commonly used in radiography of engineering and weapon components. The weapon surveillance community has a great interest in understanding how the x-rays in radiography affect short-term and long-term properties of weapon materials.
Study on corrosion properties of sputter coating of oxides on stainless steels
Y. Hayashi; M. Masuda; J. Lee; M. Kojima
To improve the corrosion resistivity of steels, the effect of oxide coating has been studied. Various oxides were coated on stainless steels by r.f. sputtering and corrosion properties of the steels were examined in acidic solutions. Structural defects, pinholes, were inevitable in the sputter-coated oxides. The defect probability was determined by electrochemical measurements and direct observations using a liquid crystal.
Mechanical Properties of Bulk Nanocrystalline Austenitic Stainless Steels Produced by Equal Channel Angular PressingĀ
Gonzalez, Jeremy
up to 600oC as indicated by retention of high hardness in annealed specimens. Furthermore, there is an increased tolerance to radiation-induced hardening in the nanocrystalline equiaxed materials subjected to 100 keV He ions at an average dose of 3...
Creep property measurements of welded joint of reduced-activation ferritic steel by the small-punch creep test
Shin-ichi Komazaki; Taichiro Kato; Yutaka Kohno; Hiroyasu Tanigawa
The small-punch (SP) test and the SP creep test were carried out by using a further miniaturized plate-type specimen (3mm diameterū0.25mm thick). Those tests were applied to the electron-beam welded joint of reduced-activation ferritic steel for evaluating the distribution of high-temperature strength in the joint. The experimental results revealed that the distribution of the maximum load measured by the SP
Mechanical properties of four RSP stainless steel alloys
Korth, G.E.
Four austenitic stainless steel alloys were processed by consolidating rapidly solidified gas atomized power using hot extrusion. These materials were characterized by measuring grain growth, hardness, tensile properties from 24 to 800{degrees}C, and creep-rupture at 600{degrees}C.
Surface microstructures and antimicrobial properties of copper plasma alloyed stainless steel
Xiangyu Zhang; Xiaobo Huang; Li Jiang; Yong Ma; Ailan Fan; Bin Tang
Bacterial adhesion to stainless steel surfaces is one of the major reason causing the cross-contamination and infection in many practical applications. An approach to solve this problem is to enhance the antibacterial properties on the surface of stainless steel. In this paper, novel antibacterial stainless steel surfaces with different copper content have been prepared by a plasma surface alloying technique
Complex Mechanical Properties of Steel
Dimitriu, Radu
?i friction stress ?y stress necessary to propagate yield ? bias A number of models in the committee CONTENTS ix a crack length a1 reliability constant a2 material fatigue properties constant a3 lubricant constant C material constant ci chemical... 2.2 ROLLING CONTACT FATIGUE Contact fatigue is a common type of failure encountered in bearings, rails, gears and valves. It differs from structural fatigue (bending or torsion) in that the cyclic stress originates in Hertzian contact, when a curved...
Tensile properties of austenitic stainless steels and their weld joints after irradiation by the ORR-spectrally-tailoring experiment
NASA Astrophysics Data System (ADS)
Jitsukawa, S.; Maziasz, P. J.; Ishiyama, T.; Gibson, L. T.; Hishinuma, A.
Tensile specimens of the Japanese heat of PCA (JPCA) and type 316 stainless steels were irradiated in spectrally tailored capsules in the Oak Ridge Research Reactor (ORR) to a peak dose of 7.4 dpa and a peak helium level of 105 appm in the temperature range between 328 and 673 K. Specimens of type 316 steel with weld joints produced by tungsten inert gas (TIG) and electron beam (EB) welding techniques were also included. Irradiation caused both increases in flow stress and decreases in elongation. Weld joint specimens exhibited both lower strength and elongation after irradiation. The reduction of area (RA) for the TIG weld joint specimens decreased by a factor of 5 compared to unirradiated base metal specimens, however, they still fractured in a ductile mode. The EB weld joints maintained RA levels similar to that of the unirradiated base metal specimens. Post-radiation ductilities of weld joints and base metal specimens of these steels should be adequate for their application to next generation fusion experimental devices, such as the International Tokamak Experimental Reactor (ITER).
Study of Mechanical Properties and Characterization of Pipe Steel welded by Hybrid (Friction Stir Weld + Root Arc Weld) Approach
Lim, Yong Chae [ORNL; Sanderson, Samuel [MegaStir Technologies LLC; Mahoney, Murray [Consultant; Wasson, Andrew J [ExxonMobil, Upstream Research Company (URC); Fairchild, Doug P [ExxonMobil, Upstream Research Company (URC); Wang, Yanli [ORNL; Feng, Zhili [ORNL
Friction stir welding (FSW) has recently attracted attention as an alternative construction process for gas/oil transportation applications due to advantages compared to fusion welding techniques. A significant advantage is the ability of FSW to weld the entire or nearly the entire wall thickness in a single pass, while fusion welding requires multiple passes. However, when FSW is applied to a pipe or tube geometry, an internal back support anvil is required to resist the plunging forces exerted during FSW. Unfortunately, it may not be convenient or economical to use internal backing support due to limited access for some applications. To overcome this issue, ExxonMobil recently developed a new concept, combining root arc welding and FSW. That is, a root arc weld is made prior to FSW that supports the normal loads associated with FSW. In the present work, mechanical properties of a FSW + root arc welded pipe steel are reported including microstructure and microhardness.
Tensile-property characterization of thermally aged cast stainless steels
Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K. [Argonne National Lab., IL (United States)
The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.
Tensile-property characterization of thermally aged cast stainless steels.
Michaud, W. F.; Toben, P. T.; Soppet, W. K.; Chopra, O. K.; Energy Technology
The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.
Influence of niobium microalloying on rotating bending fatigue properties of case carburized steels
L. Ma; M. Q. Wang; J. Shi; W. J. Hui; H. Dong
Fatigue properties of three case hardening steels have been investigated by means of rotating bending fatigue tests on smooth bar specimens after carburization. Results show that the 0.04% Nb steel had the highest fatigue limit of 1170MPa, while those of the Nb-free and 0.08% Nb steels were 995MPa and 1125MPa, respectively. It is also shown that the 0.04% Nb steel
Improving the service properties of damaged 12Kh1MF steel by nitriding from nitrogen-containing pastes
Kumanin, V.I.; Tundybaeva, E.K.; Sokolova, M.L.
Destruction of different parts of a structure begins from surface and subsurface layers of the components. This is caused by concentration of stresses and rapid development of micropores and microcracks in these volumes. This kind of destruction is characteristic of thermal power equipment, in particular, steam pipes, which are mainly made of heat-resistant steel 12Kh1MF. As is shown by experience, damage to the surface layers of equipment can be several times higher than that in the core. The aim of the present work is to estimate the possibility of eliminating microdiscontinuities or decreasing the danger of their further development by methods of chemicothermal treatment (CTT).
Structure and properties of high-temperature austenitic steels for superheater tubes
V. M. Blinov
The structure and properties of high-temperature austenitic steels intended for superheater tubes are analyzed. Widely used Kh18N10T (AISI 304) and Kh16N13M3 (AISI 316) steels are found not to ensure a stable austenitic structure and stable properties during long-term thermal holding under stresses. The hardening of austenitic steels by fine particles of vanadium and niobium carbides and nitrides and gamma'-phase and
Properties of super stainless steels for orthodontic applications.
Oh, Keun-Taek; Kim, Young-Sik; Park, Yong-Soo; Kim, Kyoung-Nam
Orthodontic stainless-steel appliances are considered to be corrosion resistant, but localized corrosion can occur in the oral cavity. This study was undertaken to evaluate the properties of super stainless steels in orthodontic applications. Accordingly, the metallurgical properties, mechanical properties, corrosion resistance, amount of the released nickel, cytotoxicity, and characteristics of the passive film were investigated. Corrosion resistances of the specimens were high and in the following order: super austenitic stainless steel (SR-50A) > super ferritic stainless steel (SFSS) = super duplex stainless steel (SR-6DX) > 316L SS > super martensitic stainless steel (SR-3Mo) in artificial saliva, 37 degrees C. At 500 mV (SCE), current densities of SR-50A, SFSS, SR-6DX, 316L SS, and SR-3Mo were 5.96 microA/cm(2), 20.3 microA/cm(2), 31.9 microA/cm(2), 805 microA/cm(2), and 5.36 mA/cm(2), respectively. Open circuit potentials of SR-50A, 316L SS, SR-6DX, SR-3Mo, and SFSS were - 0.2, - 0.22, - 0.24, - 0.43, and - 0.46 V (SCE), respectively. SR-50A, SFSS, and SR-6DX released below 3 ng/ml nickel for 8 weeks, and increased a little with immersion time, and 316L SS released about 3.5 ng/ml nickel, but SR-3Mo released a large amount of nickel, which increased with immersion time. The study demonstrated that SR-50A, SR-6DX, and SFSS have high corrosion resistance and mild or no cytotoxicity, due to the passive film enhanced by synergistic effect of Mo + N or by high addition effect of Cr + W. All super stainless steels showed very low cytotoxicity regardless of their nickel contents, although SR-3Mo was found to be relatively cytotoxic. From these studies, these steels are considered suitable for orthodontic applications. PMID:15116408
Formation and Properties of Nitrogen-rich Phases in Austenitic Stainless Steel by Plasma-based Ion Implantation
NASA Astrophysics Data System (ADS)
Hirosaki, Taketo; Tada, Yuki; Azuma, Kingo; Yatsuzuka, Mitsuyasu
Surface modification of austenitic stainless steel by plasma-based ion implantation at elevated temperatures below 450 ░C has been studied experimentally. The nitrogen depth profile at room temperature was similar to that obtained by TRIM code simulation, but the depth of nitrogen penetration increases with target temperature and reaches to a few Ąm at the treatment condition of 450 ░C and the implantation time of 2 h. High-dose nitrogen implantation more than 1018 cm-2 at the temperature above 350 ░C results in the formation of expanded austenite phase (supersaturated f. c. c. phase) with little CrN precipitation, leading to remarkable enhancement of surface hardness without loss of corrosion resistance.
Sensitivity of Steel Casting Simulation Results to Alloy Property Datasets
Beckermann, Christoph
1 Sensitivity of Steel Casting Simulation Results to Alloy Property Datasets Kent D. Carlson dataset; Ni-based alloys N3M, CW6MC and CW12MW can be represented by the benchmark CW12MW dataset; and Ni-based alloys M30C and M35-1 can be represented by the benchmark M35-1 dataset. While these alloy groupings
Effect of hydrogen on mechanical properties of nitrided austenitic steels
C. M. Lepienski; N. K. Kuromoto; J. F. P. Souza; C. E. Foerster; F. C. Serbena; S. L. R. Silva
Hydrogen (H) embrittlement in austenitic stainless steels is restricted to the surface due to the low diffusion coefficient of H in face-centred cubic (fcc) structures. Depth-sensing indentation is a very important tool to investigate the mechanical properties of hydrogenated steels at near-surface regions. In the present work, the effect of glow discharge nitriding on the mechanical properties of steels submitted
Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa
NASA Astrophysics Data System (ADS)
Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam
The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.
The effect of geometry of composite MgB 2/stainless-steel (SS) wires fabricated by PIT process on the superconducting properties
NASA Astrophysics Data System (ADS)
Song, K. J.; Kim, S. W.; Park, C.; Joo, J. H.; Choi, S. J.; Ko, R. K.; Ha, H. S.; Ha, D. W.; Oh, S. S.
Single-, multi-, and two kinds of coaxial-filament composite MgB 2/SS-SS (stainless steel for both outer and inner tubes) and MgB 2/SS-Cu (stainless steel for outer tube and copper for inner tube) wires were successfully fabricated using powder-in-tube (PIT) process with swaging only. The effect of the geometries of the MgB 2 PIT wires has been studied comparatively. The isothermal magnetizations M( H) for both the sintered and the as-rolled single-, multi-, and coaxial-filament MgB 2 wires were measured at temperatures between 5 and 50 K in fields up to 5 T. The critical current density was estimated by the M( H) data using Bean model. The coaxial-filament composite MgB 2 wires showed much better Jc than both the single- and the multi-filament composite ones. The results of this study show that the superconducting properties of the MgB 2 PIT wires/tapes can improve by employing better geometries such as the coaxial-filament composite MgB 2/SS-SS wires.
Morgan, M
The effect of hydrogen on the fracture toughness properties of Types 304L, 316L and 21-6-9 forged stainless steels was investigated. Fracture toughness samples were fabricated from forward-extruded forgings. Samples were uniformly saturated with hydrogen after exposure to hydrogen gas at 34 MPa or 69 and 623 K prior to testing. The fracture toughness properties were characterized by measuring the J-R behavior at ambient temperature in air. The results show that the hydrogen-charged steels have fracture toughness values that were about 50-60% of the values measured for the unexposed steels. The reduction in fracture toughness was accompanied by a change in fracture appearance. Both uncharged and hydrogen-charged samples failed by microvoid nucleation and coalescence, but the fracture surfaces of the hydrogen-charged steels had smaller microvoids. Type 316L stainless steel had the highest fracture toughness properties and the greatest resistance to hydrogen degradation.
Modification of surface mechanical properties of high-chromium tool steel by carbon-implanted codeposited Fe-Ti films
Hirvonen, J.P.; Nastasi, M.; Jervis, T.R.; Zocco, T.G.
An iron-titanium film 300 nm thick was deposited on a tool steel (1.55% C, 0.3% Si, 0.3% Mn, 12% Cr, 0.8% Mo, and 0.8% V) by coevaporation of Fe and Ti. Subsequently this surface film was implanted with carbon at energies of 55, 120, and 200 keV to a total fluence of 1.24 {times} 10{sup 18} C{sup +}/cm{sup 2}. This treatment produced a surface hardness of 15 GPa. The effect of this coating on unlubricated wear and friction was tested in air at a relative humidity of 10% in a pin-on-disc tester using a 440C pin as a counterface. The sliding mechanism of the untreated substrate was found to be based on the transfer of pin material and subsequent growth of uneven oxide hillocks on the wear track. Oxide scales were observed also on a wear scar of the pin, presumably as a result of back-deposition. In contrast, the sliding mechanism on the coated sample was drastically different. A more uniform transfer film originating in the coating was found on the pin, resulting in sliding between identical materials. No wearthrough of the coating occurred during the test of 5000 cycles at a Hertzian pressure of 835 MPa, and the surface of the wear track showed extreme smoothness to the very end of the test. The friction coefficient was decreased from 0.7 for the uncoated to 0.2 for the coated surface. The wear track on the coated surface was also found to be slightly oxidized, as determined by a nuclear reaction ({sup 16}O(d,p){sup 17}O). The reduction of friction was mainly attributed to the increased hardness of the counterfaces and an adequate but controlled oxidation. 15 refs., 7 figs., 2 tabs.
The Effect of Adhesion and Tensile Properties on the Formability of Laminated Steels
Robert B. Ruokolainen; David R. Sigler
Laminated steel has been implemented in vehicle structures by several automotive manufacturers to reduce in-cabin noise. This study provides an understanding of how the adhesion between the steel skin and the viscoelastic polymer core affects laminate formability. Material properties, including peel strength, shear strength, and tensile strength were determined. The presence of the viscoelastic core was found to slightly reduce
Effects of mechanical properties of paint film on the forming of pre-painted steel sheets
Kohei Ueda; Hiroshi Kanai; Takamasa Suzuki; Takeshi Amari
Formability is one of the most important factors for pre-painted steel sheets (PCMs). Both high formability of the steel substrate and high integrity of the paint films on it after processing are required. In this study, elongation, tensile strength and elastic strain energy of various paint films were examined by tensile test, and the relationship between the mechanical properties of
Fracture properties of a neutron-irradiated stainless steel submerged arc weld cladding overlay
W. R. Corwin; R. G. Berggren; R. K. Nanstad
The ability of stainless steel cladding to increase the resistance of an operating nuclear reactor pressure vessel to extension of surface flaws depends greatly on the properties of the irradiated cladding. Therefore, weld overlay cladding irradiated at temperatures and fluences relevant to power reactor operation was examined. The cladding was applied to a pressure vessel steel plate by the submerged
Review of the types, properties, advantages, and latest developments in insulating coatings on nonoriented electrical steels
Alan Coombs; M. Lindenmo; D. Snell; D. Power
Continuous efforts are directed at developing improved electrical steels with lower iron losses for energy-efficient transformers and motors. The core losses can be limited by insulating coatings, and various types of coatings have been developed for application to both fully processed and semiprocessed electrical steels. The primary and secondary properties of such coatings and the inefficacy in ultimately improving machine
Effect of deep cryogenic treatment on the mechanical properties of tool steels
A. Molinari; M. Pellizzari; S. Gialanella; G. Straffelini; K. H. Stiasny
The effect of deep cryogenic treatment (?196░C) on the properties of some tool steels was studied by means of both field tests on real tools and laboratory tests. The execution of the deep cryogenic treatment on quenched and tempered high speed steel tools increases hardness, reduces tool consumption and down time for the equipment set up, thus leading to cost
Influence of carbide and inclusion contents on the fatigue properties of high speed steels and tool steels
Fredrik Meurling; Arne Melander; Magnus Tidesten; Leif Westin
In this study the influence of carbide distribution, inclusion contents and the surface machining process on the fatigue properties of tool steels and high speed steels were investigated. Four different steels intended for cold work applications were included, of which three were powder metallurgically processed and one was conventionally ingot cast. One of the powder metallurgy steels was studied in
Ultrasonic properties of austenitic stainless steel welds
Measurements of ultrasonic velocity and attenuation were made on welded austenitic stainless steel specimens, and data correlated to flaw detectability. Measurements were made at 2.25 MHz for both longitudinal and shear waves as functions of propagation and polarization directions. The results of ultrasonic velocity measurements show that, in stainless steel welds, a high degree of anisotropy exists with respect to
Research Concerning The Mechanical And Structural Properties Of Warm Rolled Construction Carbon Steels
Medrea, C. [Technological Educational Institute of Piraeus, Depmartment of Physics, Chemistry and Materials Technology, 250 Thivon and P. Ralli Str, 12244, Aigaleo, Athens (Greece); Negrea, G.; Domsa, S. [Technical University of Cluj-Napoca, Faculty of Materials Science and Engineering, Cluj-Napoca (Romania)
Construction carbon steels represent an important steel class due to the large quantity in which it is produced. Generally, these steels are delivered in as-rolled or normalized condition heaving a ferrite-pearlite microstructure. For a given chemical composition, the mechanical characteristics of this microstructure are largely influenced by the grain size. Rolling is the deformation process which is most widely used for grain size refinement. Situated in the intermediate temperature range, warm-rolling presents certain advantages as compared to classical hot- or cold-working processes.The paper presents a study on the microstructure and mechanical properties of Ck15 carbon steel samples warm-rolled. After deformation, the microstructure was investigated by light microscopy. Hardness measurements were made on the section parallel to the rolling direction. The mechanical properties of the steel after warm-rolling were assessed by tensile and impact tests. Additional information concerning the fracture behavior of warm-rolled samples was obtained by examining the fracture surface by scanning electron microscopy. The microstructure of the steel proved to have good mechanical properties. By considering the technologic and energy aspects, the paper shows that warm-rolling can lead to the improvement of mechanical properties of construction carbon steels.
Microstructures, Mechanical Properties, and Strain Hardening Behavior of an Ultrahigh Strength Dual Phase Steel Developed by Intercritical Annealing of Cold-Rolled Ferrite/Martensite
NASA Astrophysics Data System (ADS)
Mazaheri, Y.; Kermanpur, A.; Najafizadeh, A.
A dual phase (DP) steel was produced by a new process utilizing an uncommon cold-rolling and subsequent intercritical annealing of a martensite-ferrite duplex starting structure. Ultrafine grained DP steels with an average grain size of about 2 ?m and chain-networked martensite islands were achieved by short intercritical annealing of the 80 pct cold-rolled duplex microstructure. The strength of the low carbon steel with the new DP microstructure was reached about 1300 MPa (140 pct higher than that of the as-received state, e.g., 540 MPa), without loss of ductility. Tensile testing revealed good strength-elongation balance for the new DP steels (UTS ū UE ? 11,000 to 15,000 MPa pct) in comparison with the previous works and commercially used high strength DP steels. Two strain hardening stages with comparable exponents were observed in the Holloman analysis of all DP steels. The variations of hardness, strength, elongation, and strain hardening behavior of the specimens with thermomechanical parameters were correlated to microstructural features.
Surface Modification of Stainless Steels By Carbon/nitrogen Implantation
NASA Astrophysics Data System (ADS)
Jirßskovß, Y.; Schneeweiss, O.; HavlĒ?ek, S.; Blawert, C.; Kalvelage, H.
Plasma immersion ion implantation has been used for simultaneous implantation of carbon and nitrogen into austenitic, ferritic, and duplex stainless steels at 400░C for 3 h. The surface phase composition, studied by means of Conversion Electron M÷ssbauer Spectroscopy and X-Ray difraction, is correlated with the mechanical properties represented by hardness (Vickers) measurements. The results extend information about the expanded austenite phase formed during the low temperature modification of stainless steel surface by nitrogen.
Cryogenic mechanical properties of heavy-section weldment in high-manganese austenitic steel
O. Matsumoto; T. Tsuchiyama; S. Hada
Cryogenic mechanical properties of a heavy-section weldment of high-manganese austenitic steel for the structure of superconducting magnet were evaluated, The heavy-section weld joint with a 200 mm thickness was manufactured by gas tungsten arc welding (GTAW) process using 21Mn-13Cr-5Ni-0.2N-B steel weld material. No cracks were observed in the weld metal. Tensile property and fracture toughness were tested at 4 K.
The influence of assist gas on magnetic properties of electrotechnical steel sheets cut with laser
NASA Astrophysics Data System (ADS)
Gaworska-Koniarek, Dominika; Szubzda, Bronis?aw; Wilczy?ski, Wies?aw; Drosik, Jerzy; Kara?, Kazimierz
The paper presents the influence of assist gas (air and nitrogen) during laser cutting on magnetization, magnetic permeability and loss characteristics of non-oriented electrical steels. The research was made on an non-oriented M330-50A grade electrical steels by means of single sheet tester. In order to enhance the effect of cutting and the same degradation zone on magnetic properties, strips with different width were achieved. Measurements results indicate that application of air as assist gas has more destructive effect on magnetic properties of electrical steels than nitrogen one.
Structure and properties of high-temperature austenitic steels for superheater tubes
V. M. Blinov
The structure and properties of high-temperature austenitic steels intended for superheater tubes are analyzed. Widely used\\u000a Kh18N10T (AISI 304) and Kh16N13M3 (AISI 316) steels are found not to ensure a stable austenitic structure and stable properties\\u000a during long-term thermal holding under stresses. The hardening of austenitic steels by fine particles of vanadium and niobium\\u000a carbides and nitrides and ??-phase and
Improved anticorrosion properties and electrical conductivity of 316L stainless steel as bipolar plate for proton exchange membrane fuel cell by lower temperature chromizing treatment
Lijun Yang; Haijun Yu; Lijun Jiang; Lei Zhu; Xuyu Jian; Zhong Wang
The lower temperature chromizing treatment is developed to modify 316L stainless steel (SS 316L) for the application of bipolar plate in proton exchange membrane fuel cell (PEMFC). The treatment is performed to produce a coating, containing mainly Cr-carbide and Cr-nitride, on the substrate to improve the anticorrosion properties and electrical conductivity between the bipolar plate and carbon paper. Shot peening
Effect of Hydrogen on Tensile Properties of Ultrafine-Grained Type 310S Austenitic Stainless Steel Processed by High-Pressure Torsion
NASA Astrophysics Data System (ADS)
Mine, Yoji; Tachibana, Kazutaka; Horita, Zenji
This study addresses a hydrogen effect on the tensile properties of a type 310S austenitic stainless steel with ultrafine-grained structures produced by high-pressure torsion (HPT) and subsequent annealing. The mean grain size was reduced to ~85 nm by the HPT processing. The grain size was increased by the post-HPT annealing, but the grain size of ~265 nm was retained after annealing at 1023 K (750 ░C). The tensile strength of ~1.2 GPa, which is approximately twice as much as that of the solution-treated specimen, was attained in the 1023 K (750 ░C) post-HPT-annealed specimen. The elongation to failure was restored up to ~15 pct by the post-HPT annealing, although it was still insufficient in comparison with the ~55 pct elongation of the solution-treated specimen. There was no change in the tensile strength of the HPT-processed specimens and the post-HPT-annealed specimens by hydrogen charging with the hydrogen content in the range of ~20 to 40 mass ppm. The HPT-processed and the 773 K (500 ░C) post-HPT-annealed specimens exhibited a ductility loss through the fully shear type fracture. The hydrogen charge into higher temperature post-HPT-annealed specimens with ?-FeCr precipitates led to a mild hydrogen embrittlement.
Mechanical properties of structural amorphous steels: Intrinsic correlations, conflicts, and optimizing strategies
NASA Astrophysics Data System (ADS)
Liu, Z. Q.; Zhang, Z. F.
Amorphous steels have demonstrated superior properties and great potentials for structural applications since their emergence, yet it still remains unclear about how and why their mechanical properties are correlated with other factors and how to achieve intended properties by designing their compositions. Here, the intrinsic interdependences among the mechanical, thermal, and elastic properties of various amorphous steels are systematically elucidated and a general trade-off relation is exposed between the strength and ductility/toughness. Encouragingly, a breakthrough is achievable that the strength and ductility/toughness can be simultaneously improved by tuning the compositions. The composition dependences of the properties and alloying effects are further analyzed thoroughly and interpreted from the fundamental plastic flow and atomic bonding characters. Most importantly, systematic strategies are outlined for optimizing the mechanical properties of the amorphous steels. The study may help establish the intrinsic correlations among the compositions, atomic structures, and properties of the amorphous steels, and provide useful guidance for their alloy design and property optimization. Thus, it is believed to have implications for the development and applications of the structural amorphous steels.
Structural characterization and magnetic properties of steels subjected to fatigue
C. C. H. Lo; F. Tang; S. B. Biner; D. C. Jiles
Studies have been made on the effects of residual stress and microstructure on the variations of magnetic properties of steels during fatigue. Strain-controlled fatigue tests have been conducted on 0.2wt% C steel samples which were (1) cold-worked, (2) cold-worked and annealed at 500 ░C to relieve residual stress, and (3) annealed at 905 ░C to produce a ferrite\\/pearlite structure. The
The effects of hydrogen on the fracture toughness properties of upset welded stainless steel
Morgan, M.T.
The effects of hydrogen on the fracture toughness properties of upset welded Type 304L stainless steel were measured and compared to those measured previously for as-received and as-welded steels. The results showed that the upset welded steels had good fracture toughness properties, but values were lower than the as-received material. The fracture toughness value of the base material was 6420 in-lbs/sq. in., while the welded steels averaged 3660 in-lbs/sq. in. Hydrogen exposure lowered the fracture toughness values of the as-received steel by 43 % to 3670 in-lbs/sq. in. and the welded steels by 21 % to 2890 in-lbs/sq. in. The fracture morphologies of the unexposed steels showed that ductile fracture occurred by the microvoid nucleation and growth process. The size of the microvoids on the fracture surfaces of the welded steels were much smaller and more closely spaced that those found on the base material fracture surfaces. The change in the size and spacing of the microvoids indicates that the fracture toughness properties of the welded steels were lower than the base steels because of the higher concentration of microscopic precipitates on the weld plane. The welds examined thus far have been {open_quotes}good{close_quotes} welds and the presence of these precipitates was not apparent in standard {open_quotes}low{close_quotes}-magnification metallographic sections of the weld planes. The results indicate that hydrogen did not weaken greatly the solid-state welds but that other inclusions or impurities present prior to welding did. Improvements in surface cleaning and preparation prior to welding should be explored as a way to improve the strength of solid-state welded joints.
The properties and weldability of low activation ferritic steels
Chin, B.A.
A series of ferritic steels patterned on the chromium-molybdenum alloys, 2 1/4Cr--1Mo, 9Cr--1MoVNb and 12Cr--1MoVW, were tested for weldability. These steels are being developed as candidates for the first wall and blanket structures of fusion reactors. Use of these materials will minimize the long term radioactive hazards associated with disposal after service. In these low activation alloys, elements which become activated during irradiation with long half lives (Mo and Nb) are replaced. The major changes include the replacement of molybdenum with tungsten, the addition of vanadium in 2 1/4% Cr steels, and the replacement of niobium in the 9% Cr steel with tantalum. These replacement elements radically modify both the mechanical properties and weldability of the alloys. In this study, the effect of the alloy modifications on the microstructure and the mechanical properties of the welds are presented. Bainitic steels (2 1/4 Cr%) usually exhibit good weldability, while the martensitic steels (5, 9 and 12 Cr%) are suspectable to embrittlement in the heat affected zone (HAZ). The objective of this study was to characterize the welded microstructure and mechanical properties of these low activation alloys. Autogeneous bead-on-plate welds were produced using the gas tungsten arc welding (GTAW) process. Microstructure, microhardness, weld bend and tensile test results are reported for the base metal, heat affected zone and fusion zone of the weld. 46 refs., 36 figs., 14 tabs.
Tubes of steel 15Kh25T with improved properties
Yastrebava, M.A.; Belinkii, A.L.; Logvinov, V.I.
Tubes made of steel 15Kh with improved technological properties and guaranteed resistance to intergranular corrosion are now being manufactured. Investigations of an experimental lot of tubes with a diameter of 38 x 2.5 mm carried out showed that these tubes have better technological and mechanical properties than tubes manufactured according to state standard GOST 9941-81. The results of tensile tests of the tubes at possible service temperature are given. These tubes can be recommended for the manufacture of tube bundles of heat-exchange equipment operating at temperatures from 0 degrees C to +300 degrees C under pressures up to 1.6 MPa when they are joined to a tube grid by rolling (without welding).
Weld Properties of a Free Machining Stainless Steel
J. A. Brooks; S. H. Goods; C. V. Robino
The all weld metal tensile properties from gas tungsten arc and electron beam welds in free machining austenitic stainless steels have been determined. Ten heats with sulfur contents from 0.04 to 0.4 wt.% and a wide range in Creq/Nieq ratios were studied. Tensile properties of welds with both processes were related to alloy composition and solidification microstructure. The yield and ultimate tensile strengths increased with increasing Creq/Nieq ratios and ferrite content, whereas the ductility measured by RA at fracture decreased with sulfur content. Nevertheless, a range in alloy compositions was identified that provided a good combination of both strength and ductility. The solidification cracking response for the same large range of compositions are discussed, and compositions identified that would be expected to provide good performance in welded applications.
Structure and properties of high-temperature austenitic steels for superheater tubes
NASA Astrophysics Data System (ADS)
Blinov, V. M.
The structure and properties of high-temperature austenitic steels intended for superheater tubes are analyzed. Widely used Kh18N10T (AISI 304) and Kh16N13M3 (AISI 316) steels are found not to ensure a stable austenitic structure and stable properties during long-term thermal holding under stresses. The hardening of austenitic steels by fine particles of vanadium and niobium carbides and nitrides and ?'-phase and Fe2W and Fe2Mo Laves phase intermetallics is considered. The role of Cr23C6 chromium carbides, the ? phase, and coarse precipitates of an M 3B2 phase and a boron-containing eutectic in decreasing the time to failure and the stress-rupture strength of austenitic steels is established. The mechanism of increasing the stress-rupture strength of steels by boron additions is described. The chemical compositions, mechanical properties, stress-rupture strength, and creep characteristics of Russian and foreign austenitic steels used or designed for superheater tubes intended for operation under stress conditions at temperatures above 600░C are presented. The conditions are found for increasing the strength, plasticity, and thermodeformation stability of austenite in steels intended for superheater tubes operating at 700░C under high stresses for a long time.
Mechanical Properties and Microstructural Evolution of Welded Eglin Steel
NASA Astrophysics Data System (ADS)
Leister, Brett M.
Eglin steel is a new ultra-high strength steel that has been developed at Eglin Air Force Base in the early 2000s. This steel could be subjected to a variety of processing steps during fabrication, each with its own thermal history. This article presents a continuous cooling transformation diagram developed for Eglin steel to be used as a guideline during processing. Dilatometry techniques performed on a Gleeble thermo-mechanical simulator were combined with microhardness results and microstructural characterization to develop the diagram. The results show that four distinct microstructures form within Eglin steel depending on the cooling rate. At cooling rates above about 1 ░C/s, a predominately martensitic microstructure is formed with hardness of ś520 HV. Intermediate cooling rates of 1 ░C/s to 0.2 ░C/s produce a mixed martensitic/bainitic microstructure with a hardness that ranges from 520 - 420 HV. Slower cooling rates of 0.1 ░C/s to 0.03 ░C/s lead to the formation of a bainitic microstructure with a hardness of ś420 HV. The slowest cooling rate of 0.01 ░C/s formed a bainitic microstructure with pearlite at the prior austenite grain boundaries. A comprehensive study was performed to correlate the mechanical properties and the microstructural evolution in the heat affected zone of thermally simulated Eglin steel. A Gleeble 3500 thermo-mechanical simulator was used to resistively heat samples of wrought Eglin steel according to calculated thermal cycles with different peak temperatures at a heat input of 1500 J/mm. These samples underwent mechanical testing to determine strength and toughness, in both the `as-simulated' condition and also following post-weld heat treatments. Mechanical testing has shown that the inter-critical heat affected zone (HAZ) has the lowest strength following thermal simulation, and the fine-grain and coarse-grain heat affected zone having an increased strength when compared to the inter-critical HAZ. The toughness of the heat affected zone in the as-simulated condition is lower than that of the base metal. Post-weld heat treatments (PWHT) have been shown to increase the toughness of the HAZ, but at the expense of strength. In addition, certain combinations of PWHTs within specific HAZ regions have exhibited low toughness caused by tempered martensite embrittlement or intergranular failure. Synchrotron X-ray diffraction data has shown that Eglin steel has retained austenite in the fine-grain HAZ in the as-simulated condition. In addition, alloy carbides (M23C 6, M2C, M7C3) have been observed in the diffraction spectra for the fine-grain and coarse-grain HAZ following a PWHT of 700 ░C / 4 hours. A first attempt at thermodynamic modeling has been undertaken using MatCalc to try to predict the evolution of carbides in the HAZ following thermal cycling and PWHT.
Application of artificial neural network for predicting strain-life fatigue properties of steels on the basis of tensile tests
K Genel
The applicability of artificial neural networks (ANN) in predicting the strain-life fatigue properties using tensile material data for 73 steels was investigated by conducting four separate neural networks for individual fatigue properties. The fatigue data of these steels extracted from available literatures were used in the formation of training set of ANN. Results of neural network modelling indicated that fatigue
Microstructure¢property relationship in explosively welded duplex stainless steel¢steel
R Kańar; M Acarer
Duplex stainless steel (2205 grade) and vessel steel (DIN-P355GH grade) were cladded by explosive welding. The relationship between hardness, tensile shear strength and toughness and microstructure of cladded materials were evaluated. The bond interface of the cladded materials shows a wavy morphology. The hardness was similar in the base and flyer plate near the bond interface while a general increase
BS>Semiaustenitic hardenable stainless steels types AM-350 and AM-355 ; were found to have excellent weldability by the same techniques and processes ; that are used for austenitic stainiess steels. By appropriate low-temperature ; postweld heat treatments, the weld and base metals may be transformed to a high-; strength tempered martensitic structure. Both alloys have welded and hardened ; strengths equal
The dependence of magnetic properties on fatigue in A533B nuclear pressure vessel steels
Y. Bi; M. R. Govindaraju; D. C. Jiles
Cyclic loading causes cumulative microstructural changes in materials. The magnetic properties of A533B steel are determined by both initial microstructures and microstructural changes induced by fatigue damage. From the results of a series of strain-controlled fatigue tests, the magnetic properties were found to change systematically with fatigue damage throughout the fatigue life. A linear relationship between magnetic remanence and mechanical
Influence of thermal aging on microstructure and mechanical properties of CLAM steel
NASA Astrophysics Data System (ADS)
Huang, Lixin; Hu, Xue; Yang, Chunguang; Yan, Wei; Xiao, Furen; Shan, Yiyin; Yang, Ke
In order to investigate the influence of thermal aging on microstructure and mechanical properties of CLAM (China low activation martensitic) steel, a comparison study was made on the as-tempered and the aged steels. The tempered CLAM steels were subjected to aging treatment at 600 ░C for 1100 h and 3000 h, and at 650 ░C for 1100 h, respectively. The changes of microstructure were characterized by both transmission electron microscope (TEM) and scanning electron microscope (SEM). The mechanical properties were evaluated by Charpy impact, tensile and Vickers hardness tests. The upper shelf energy (USE) of the thermal aged CLAM steel decreased with the extension of aging time, while the yield strength changed slightly. After long-term thermal aging, the MX type precipitates remained stable. The coarsening of M23C6 and the formation of Laves phase were confirmed by scanning/transmission electron microscopes. The Laves phase was the main factor leading to the increase of DBTT.
Property assessment of steel¢fibre reinforced concrete made with silica fume
Mahmoud Nili; Vahid Afroughsabet
When silica fume was used as a cement replacement, it enhanced the effectiveness of added steel fibre on the properties of concrete. Three different steel fibres were used at 0.0%, 0.5% and 1.0% by volume of concrete. Silica fume was introduced at 8% by weight of cement into the concrete mixtures that were made with water¢cement ratios of 0.46 and
Effect of copper precipitates on the stability of microstructures and magnetic properties of non-oriented electrical steels
NASA Astrophysics Data System (ADS)
Wu, Meng; Zeng, Yanping
Non-oriented electrical steels with different amounts of copper were prepared and the microstructure and magnetic properties of each kind of steel were studied. The results show that there exist a large number of Cu-rich metastable precipitates in the hot-rolled bands of the steels containing copper. They not only can decrease the sensitivity of the microstructures and magnetic properties of the steels to the change of process parameters but also can significantly reduce the core loss of the steels by improving the recrystallization textures without obviously decreasing the magnetic induction. Therefore, it is possible to control the microstructures and then magnetic properties of non-oriented electrical steels by the copper precipitates.
S. Koshiba; T. Kuno
Samples of heat-resistant Nimonic 80A, S816 alloys, and l3% Cr stainless ; steel were melted in vacuum, and their various properties were compared with ; specimens melted in open air. By vacuum melting of 13% Cr stainless steel, the ; gas contents and nonmetallic inclusions in steel were much decreased, and the ; mechanical properties at elevated temperature were improved.
Magnetic and structural properties of ion nitrided stainless steel
NASA Astrophysics Data System (ADS)
Basso, R. L. O.; Pimentel, V. L.; Weber, S.; Marcos, G.; Czerwiec, T.; Baumvol, I. J. R.; Figueroa, C. A.
The magnetic properties and crystalline structure of expanded austenite obtained by ion beam nitriding of AISI 316 steel are investigated. Magnetic force microscopy reveals that the nitrogen expanded austenite has two different layers, an outermost ferromagnetic layer and a paramagnetic layer beneath it. Superimposing the nitrogen concentration profile determined by secondary neutral mass spectrometry and the magnetic force microscopy image, one can see that the paramagnetic-ferromagnetic transition takes place at the inflection point of the nitrogen concentration profile at about 14▒2 N at. %. Conventional and glancing angle x-ray diffraction suggests that nitrogen could occupy first tetrahedral interstitial positions (nitrogen-poor paramagnetic phase) and then, after saturation of Cr traps, octahedral interstitial positions (nitrogen-rich ferromagnetic phase). The ferromagnetic-paramagnetic transition is seen to be governed by Cr (traps)-N interactions.
Effect of zirconium addition on the microstructure and mechanical properties of ODS ferritic steels containing aluminum
NASA Astrophysics Data System (ADS)
Gao, R.; Zhang, T.; Wang, X. P.; Fang, Q. F.; Liu, C. S.
The oxide dispersion strengthened (ODS) ferritic steels with nominal composition of Fe-16Cr-2W-0.5Ti-0.4Y2O3-4Al-1Zr (16Cr-4Al-Zr-ODS) were fabricated by a sol-gel method combining with mechanical alloying and spark plasma sintering (SPS) technique, and the 16Cr-ODS and 16Cr-4Al-ODS steels were prepared for comparison in the same way. Microstructure characterization reveals that in the 16Cr-4Al-ODS steel coarse Y-Al-O particles were formed while in the 16Cr-4Al-Zr-ODS steel finer Y-Zr-O particles were formed. The mean size and number density of the nano-oxide particles in the 16Cr-4Al-Zr-ODS steel are about 25 nm and 2.6 ū 1021/m3, respectively. The ultimate tensile strength (UTS) of the 16Cr-ODS steel is about 1045 MPa, but UTS of the 16Cr-4Al-ODS steel decreases to 974 MPa. However, UTS of the 16Cr-4Al-Zr-ODS steel increases to 1180 MPa while keeping a large uniform elongation up to 23%, indicating the enhancement of mechanical properties by Zr addition.
The Effect of Adhesion and Tensile Properties on the Formability of Laminated Steels
Robert B. Ruokolainen; David R. Sigler
Laminated steel has been implemented in vehicle structures by several automotive manufacturers to reduce in-cabin noise. \\u000a This study provides an understanding of how the adhesion between the steel skin and the viscoelastic polymer core affects\\u000a laminate formability. Material properties, including peel strength, shear strength, and tensile strength were determined.\\u000a The presence of the viscoelastic core was found to slightly reduce
Guidance properties on the surface of copper and stainless steel wires in terahertz frequency range
Tae-In Jeon; Young Bin Ji; Eui Su Lee; Jin Seok Jang; Min Hwan Kwak; Kang-Yong Kwang
We report an experimental and theoretical study of the guidance properties on the surface of copper and stainless steel wires in the terahertz frequency range. Instead of using quasioptic coupling, optoelectronically generated THz pulses by silicon on sapphire (SOS) photoconductive dipole antenna were directly launched onto a 0.5-mm-diameter copper and stainless steel wire. After a 71-cm propagation of the curved
Effect of Heat Treatment on the Microstructure and Mechanical Properties of Stainless Steel 316L Coatings Produced by Cold Spray for Biomedical Applications
NASA Astrophysics Data System (ADS)
AL-Mangour, Bandar; Vo, Phuong; Mongrain, Rosaire; Irissou, Eric; Yue, Stephen
In this study, the effects of heat treatment on the microstructure and mechanical properties of cold sprayed stainless steel 316L coatings using N2 and He as propellant gases were investigated. Powder and coating characterizations, including coating microhardness, coating porosity, and XRD phase analysis were performed. It was found that heat treatment reduced porosity, improved inter-particle bonding, and increased ductility. XRD results confirmed that no phase transformation occurred during deposition. Significant increase in UTS and ductility was observed for the annealed specimens obtained with nitrogen propellant, whereas little changes were observed for the helium propellant produced specimen.
Effect of tungsten on tensile properties and flow behaviour of RAFM steel
NASA Astrophysics Data System (ADS)
Vanaja, J.; Laha, K.; Nandagopal, M.; Sam, Shiju; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.
Effect of tungsten in the range of 1-2 wt.% on tensile properties and flow behaviour of 9Cr-W-Ta-V Reduced Activation Ferritic-Martensitic (RAFM) steel has been investigated. The tungsten in the investigated range was found to have only minor effect on the tensile properties of the steel over the temperature range of 300-873 K and at a strain rate of 3 ū 10-3 s-1. The tensile flow behaviour of the RAFM steels was adequately described by the Voce's constitutive equation. The tensile strength of the steels were predicted well from the parameters of the Voce's constitutive equation. The Voce's strain hardening parameter 'nv' was found to be quite sensitive to the tungsten content and predicted the onset of dislocation climbing process at relatively higher testing temperature with the increase in tungsten content. The equivalence between tensile and creep deformations and the influence of tungsten have been discussed.
Mechanical Properties of Structural Steels in Hydrogen
.1 0.08 0.06 0.04 0.02 0 0.5 0.6 0.7 0.8 0.9 1 a/ W ASTM E1681: KI = 57.5 MPa m FEM elastic: KI = 63.2MPa m 1- ASTM E1681 FEM #12;Incubation time for crack extension depends on Ko Initial stress in H2 X100 Steel WOL specimens 15 kpsi H2 gas 25 o C no crack extension after >2500 hr KTH
Porollo, S. I.; Konobeev, Yu V.; Dvoriashin, A. M.; Budylkin, N. I.; Mironova, E. G.; Leontyeva-Smirnova, M. V.; Loltukhovsky, A. G.; Bochvar, A. A.; Garner, Francis A.
Russian ferritic/martensitic steels EP-450 and EP-823 were irradiated to 20-60 dpa in the BN-350 fast reactor in the form of pressurized creep tubes and small rings used for mechanical property tests. Data derived from these steels serves to enhance our understanding of the general behavior of this class of steels. It appears that these steels exhibit behavior that is very consistent with that of Western steels. Swelling is relatively low at high neutron exposure and confined to temperatures less then 420 degrees C, but may be camouflaged somewhat by precipitation-related densification. The irradiation creep studies confirm that the creep compliance of F/M steels is about one-half that of austenitic steels, and that the loss of strength at test temperatures above 500 degrees C is a problem generic to all F/M steels. This conclusion is supported by post-irradiation measurement of short-term mechanical properties. At temperatures below 500 degrees C both steels retain their high strength (yield stress 0.2=550-600 MPa), but at higher test temperatures a sharp decrease of strength properties occurs. However, the irradiated steels still retain high post-irradiation ductility at test temperatures in the range of 20-700 degrees C.
Influence of Steel Melting Processes on Tensile Properties of 14Cr-15Ni-Ti Stainless Steel
NASA Astrophysics Data System (ADS)
Nandagopal, M.; Parameswaran, P.; Vijayanand, V. D.; Laha, K.; Mathew, M. D.
A titanium-modified 14Cr-15Ni-2Mo austenitic stainless steel, known as alloy D9, has been chosen as the material for the fuel cladding and hexagonal wrapper of the Prototype Fast Breeder Reactor presently under construction at Kalpakkam. The alloy is generally produced by double vacuum melting process consisting of Vacuum Induction Melting (VIM) followed by Vacuum Arc Remelting (VAR). An alternate route consisting of vacuum induction melting followed by electro slag refining (ESR) has been employed to produce the alloy with lower inclusion content Tensile studies were carried out at various temperatures between ambient and 1023 K at an interval of 50 K and strain rate of 1.2 ū 10-3 s-1 on the steels in 20% coldworked condition. Tensile properties of both VAR grade and ESR grade material were found to be similar. The influence of the secondary processing routes on the mechanical properties of alloy D9 is studied.
Stalheim, Mr. Douglas [DGS Metallurgical Solutions Inc; Boggess, Todd [Secat; San Marchi, Chris [Sandia National Laboratories (SNL); Jansto, Steven [Reference Metals Company; Somerday, Dr. B [Sandia National Laboratories (SNL); Muralidharan, Govindarajan [ORNL; Sofronis, Prof. Petros [University of Illinois
The continued growth of the world s developing countries has placed an ever increasing demand on traditional fossil fuel energy sources. This development has lead to increasing research and development of alternative energy sources. Hydrogen gas is one of the potential alternative energy sources under development. Currently the most economical method of transporting large quantities of hydrogen gas is through steel pipelines. It is well known that hydrogen embrittlement has the potential to degrade steel s mechanical properties when hydrogen migrates into the steel matrix. Consequently, the current pipeline infrastructure used in hydrogen transport is typically operated in a conservative fashion. This operational practice is not conducive to economical movement of significant volumes of hydrogen gas as an alternative to fossil fuels. The degradation of the mechanical properties of steels in hydrogen service is known to depend on the microstructure of the steel. Understanding the levels of mechanical property degradation of a given microstructure when exposed to hydrogen gas under pressure can be used to evaluate the suitability of the existing pipeline infrastructure for hydrogen service and guide alloy and microstructure design for new hydrogen pipeline infrastructure. To this end, the 2 Copyright 2010 by ASME microstructures of relevant steels and their mechanical properties in relevant gaseous hydrogen environments must be fully characterized to establish suitability for transporting hydrogen. A project to evaluate four commercially available pipeline steels alloy/microstructure performance in the presences of gaseous hydrogen has been funded by the US Department of Energy along with the private sector. The microstructures of four pipeline steels were characterized and then tensile testing was conducted in gaseous hydrogen and helium at pressures of 800, 1600 and 3000 psi. Based on measurements of reduction of area, two of the four steels that performed the best across the pressure range were selected for evaluation of fracture and fatigue performance in gaseous hydrogen at 800 and 3000 psi. This paper will describe the work performed on four commercially available pipeline steels in the presence of gaseous hydrogen at pressures relevant for transport in pipelines. Microstructures and mechanical property performances will be compared. In addition, recommendations for future work related to gaining a better understanding of steel pipeline performance in hydrogen service will be discussed.
Author's personal copy Magnetic properties of stainless steels at room and cryogenic temperatures
Oxley, Paul
Author's personal copy Magnetic properties of stainless steels at room and cryogenic temperatures: Magnetic measurement Ferromagnetic property Stainless steel Martensitic Ferritic a b s t r a c t The magnetic properties of ten types of ferritic and martensitic stainless steels have been measured at room
Effects of Aging Structures and Humidity on Fatigue Properties of Maraging Steel
NASA Astrophysics Data System (ADS)
Hayashi, Kousuke; Nagano, Takanori; Moriyama, Michihiko; Wang, Xishu; Kawagoishi, Norio
Effects of aging structures and humidity on fatigue properties of 350 grade 18% Ni maraging steel were investigated under rotating bending in relative humidity of 25% and 85%. Aging conditions tested were a conventional single aging and a double one which was aged at low temperature after the conventional aging. In each aging, under and peak aged steels were prepared. Tensile strength was increased by the double aging without reduction of the ductility. Proportional relation between fatigue limit and Vickers hardness held until 750HV in low humidity. However fatigue strength was largely decreased by high humidity, especially in the peak aged steel at the single aging. The decrease in fatigue strength by high humidity was mainly caused by the acceleration of a crack initiation due to the anodic dissolution. The acceleration of a crack initiation was larger in the steel peak aged at the single aging with larger precipitated particles.
Microstructure and property modifications of an AISI H13 (4Cr5MoSiV) steel induced by pulsed electron beam treatment
Zhang Kemin; Zou Jianxin; Grosdidier, Thierry; Dong Chuang [School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Shanghai Engineering Research Center of Mg Materials and Applications and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China) and Laboratoire d'Etude des Textures et Applications aux Materiaux (LETAM, CNRS 3143), Universite Paul Verlaine Metz, Ile du Saulcy, 57045 Metz (France); Laboratoire d'Etude des Textures et Applications aux Materiaux (LETAM, CNRS 3143), Universite Paul Verlaine Metz, Ile du Saulcy, 57045 Metz (France) and Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116024 (China); Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116024 (China)
In the present work, surface modifications generated by the low energy high current pulsed electron beam (LEHCPEB) treatments have been investigated on an AISI H13 (4Cr5MoSiV) steel. From the observations of scanning electron microscopy, x-ray diffraction, and electron back scattering diffraction determinations, it could be established that the final structure in the melted layer is a mixture of ultrafine {delta} phase, martensite, and residual austenite. The formation of the heterogeneous microstructures on the surface layer is related to the very rapid heating, melting, solidification, and cooling induced by the LEHCPEB irradiation. After the LEHCPEB treatment, the wear resistance of the steel effectively improved. This can be mainly attributed to the higher hardness of the ultrafine structures formed on the top surface and the hardened subsurface layers after the treatment.
Adsorption Properties and Inhibition of Mild Steel Corrosion in 0.5 M H2SO4 Solution by Some Triazol Compound
NASA Astrophysics Data System (ADS)
Tao, Z.; He, W.; Wang, S.; Zhang, S.; Zhou, G.
The effect of 3,5-dimethylbenzoic acid [1,2,4]triazol derivative (DBTE) on the corrosion of mild steel in 0.5 M H2SO4 solution was evaluated in this study by means of weight loss test, EIS, potentiodynamic polarization, and SEM. The results revealed that DBTE acted as a mixed-type inhibitor without change of the mechanism of hydrogen evolution. The inhibition efficiency increased with the increase in concentration of DBTE, and the adsorption behavior of DBTE on the mild steel surface followed the Langmuir adsorption isotherm. The thermodynamic parameters reveal that the chemisorption was the dominant adsorption process, and good inhibition performances in the studied range of temperatures were observed.
Investigation of the structure and properties of titanium-stainless steel permanent joints obtained by laser welding with the use of intermediate inserts and nanopowders
NASA Astrophysics Data System (ADS)
Cherepanov, A. N.; Orishich, A. M.; Pugacheva, N. B.; Shapeev, V. P.
Results of an experimental study of the structure, the phase composition, and the mechanical properties of laser-welded joints of 3-mm thick titanium and 12Kh18N10T steel sheets obtained with the use of intermediate inserts and nanopowdered modifying additives are reported. It is shown that that such parameters as the speed of welding, the radiation power, and the laser-beam focal spot position all exert a substantial influence on the welding-bath process and on the seam structure formed. In terms of chemical composition, most uniform seams with the best mechanical strength are formed at a 1-m/min traverse speed of laser and 2.35-kW laser power, with the focus having been positioned at the lower surface of the sheets. Under all other conditions being identical, uplift of the focus to workpiece surface or to a higher position results in unsteady steel melting, in a decreased depth and reduced degree of the diffusion-induced mixing of elements, and in an interpolate connection formed according to the soldering mechanism in the root portion of the seam. The seam material is an over-saturated copper-based solid solution of alloying elements with homogeneously distributed intermetallic disperse particles (Ti(Fe, Cr)2 and TiCu3) contained in this alloy. Brittle fracture areas exhibiting cleavage and quasi-cleavage facets correspond to coarse Ti(Fe, Cr)2 intermetallic particles or to diffusion zones primarily occurring at the interface with the titanium alloy. The reported data and the conclusions drawn from the numerical calculations of the thermophysical processes of welding of 3-mm thick titanium and steel sheets through an intermediate copper insert are in qualitative agreement with the experimental data. The latter agreement points to adequacy of the numerical description of the melting processes of contacting materials versus welding conditions and focal-spot position in the system.
A Novel Ni-Containing Powder Metallurgy Steel with Ultrahigh Impact, Fatigue, and Tensile Properties
NASA Astrophysics Data System (ADS)
Wu, Ming-Wei; Shu, Guo-Jiun; Chang, Shih-Ying; Lin, Bing-Hao
The impact toughness of powder metallurgy (PM) steel is typically inferior, and it is further impaired when the microstructure is strengthened. To formulate a versatile PM steel with superior impact, fatigue, and tensile properties, the influences of various microstructures, including ferrite, pearlite, bainite, and Ni-rich areas, were identified. The correlations between impact toughness with other mechanical properties were also studied. The results demonstrated that ferrite provides more resistance to impact loading than Ni-rich martensite, followed by bainite and pearlite. However, Ni-rich martensite presents the highest transverse rupture strength (TRS), fatigue strength, tensile strength, and hardness, followed by bainite, pearlite, and ferrite. With 74 pct Ni-rich martensite and 14 pct bainite, Fe-3Cr-0.5Mo-4Ni-0.5C steel achieves the optimal combination of impact energy (39 J), TRS (2170 MPa), bending fatigue strength at 2 ū 106 cycles (770 MPa), tensile strength (1323 MPa), and apparent hardness (38 HRC). The impact energy of Fe-3Cr-0.5Mo-4Ni-0.5C steel is twice as high as those of the ordinary high-strength PM steels. These findings demonstrate that a high-strength PM steel with high-toughness can be produced by optimized alloy design and microstructure.
Surface properties of nitrided layer on AISI 316L austenitic stainless steel produced by high temperature plasma nitriding in short time
NASA Astrophysics Data System (ADS)
Li, Yang; Wang, Zhuo; Wang, Liang
It has generally been believed that the formation of the S phase or expanded austenite ?N with enough thickness depends on the temperature (lower than 480 ░C) and duration of the process. In this work, we attempt to produce nitrogen expanded austenite layer at high temperature in short time. Nitriding of AISI 316L austenitic stainless steel was carried out at high temperatures (>520 ░C) for times ranging from 5 to 120 min. The microstructures, chemical composition, the thickness and the morphology of the nitrided layer, as well as its surface hardness, were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, optical microscopy, scanning electron microscopy, and microhardness tester. The corrosion properties of the untreated and nitrided samples were evaluated using anodic polarization tests in 3.5% NaCl solution. The results confirmed that nitrided layer was shown to consist of ?N and a small amount of free-CrN and iron nitrides. High temperature plasma nitriding not only increased the surface hardness but also improved the corrosion resistance of the austenitic stainless steel, and it can critically reduce processing time compared with low temperature nitriding.
Properties of laminated steel-silver composite materials
V. P. Maiboroda
1.The tensile strength sv (130 kg mm2) and microhardness HV (350 kg\\/mm2) of 08kp steel-Ag multilayer composite materials (MCM) substantially exceed both sv and HV of alloy mixtures of the same composition (65 and 150 kg\\/mm2, respectively) and sv and HV of 08kp steel (90 and 180¢200 kg\\/mm2, respectively).2.The gain in strength ?sv due to the work-hardening induced by rolling
Radiation effects on the mechanical properties of stainless steels
NASA Astrophysics Data System (ADS)
Aono, Y.; Abe, H.; Kuramoto, E.; Tsukuda, N.; Takenaka, M.; Kinoshita, T.; Yoshida, H.
Stainless steels irradiated by electrons at 77 K were deformed at 77 and 290 K in order to investigate the isochronal annealing effects on their yield strengths in the temperature range 77 to 900 K. The austenitic stainless steel (JPCA-2) showed large irradiation hardening both for the 77 and 290 K. test. Furthermore, it was found from the test at 290 K that this hardening remained up to 900 K. On the contrary, for the ferritic/martensitic or martensitic stainless steel (JFMS or HT-9) irradiation softening was observed. In particular, both the isochronal annealing curves for the HT-9 with a single tempered martensite phase indicated that a large reduction of the yield stress amounted to 20-30% and this softening did not change during annealing up to 900 K. Furthermore, the characteristic feature of the ferritic/martensitic stainless steels was examined using pure Fe-Cr and Fe-Cr-C alloys as controls.
The Effect of Dynamic Strain Aging on Subsequent Mechanical Properties of Dual-Phase Steels
NASA Astrophysics Data System (ADS)
Molaei, M. J.; Ekrami, A.
Dual-phase (DP) steels with different martensite contents were produced by subjecting a low carbon steel to various heat treatment cycles. In order to investigate the effect of dynamic strain aging (DSA) on mechanical properties, tensile specimens were deformed 3% at 300 ░C. Room temperature tensile tests of specimens which deformed at 300 ░C showed that both yield and ultimate tensile strengths increased, while total elongation decreased. The fatigue limit increased after pre-strain in the DSA temperature range. The effects of martensite volume fraction on mechanical properties were discussed.
Charpy toughness and tensile properties of a neutron irradiated stainless steel submerged-arc weld cladding overlay
W. R. Corwin; R. G. Berggren; R. K. Nanstad
The possibility of stainless steel cladding increasing the resistance of an operating nuclear reactor pressure vessel to extension of surface flaws is highly dependent upon the irradiated properties of the cladding. Therefore, weld overlay cladding irradiated at temperatures and fluences relevant to power reactor operation was examined. The cladding was applied to a pressure vessel steel plate by the submerged-arc,
Effects of Manganese Content on Solidification Structures, Thermal Properties, and Phase Transformation Characteristics in Fe-Mn-C Steels
NASA Astrophysics Data System (ADS)
Yang, Jian; Wang, Yu-Nan; Ruan, Xiao-Ming; Wang, Rui-Zhi; Zhu, Kai; Fan, Zheng-Jie; Wang, Ying-Chun; Li, Cheng-Bin; Jiang, Xiao-Fang
The solidification structures and the thermal properties of Fe-Mn-C steel ingots containing different manganese contents have been investigated and the phase transformation characteristics have been revealed by Thermo-Calc to assist development of the continuous casting technology of Fe-Mn-C steels. The results show that the thermal conductivity of the 0Mn steel is higher than that of the 3Mn steel. The thermal conductivity of the 6Mn steel is the lowest in the three kinds of steels below 1023 K (750 ░C) and the highest above 1173 K (900 ░C). The 0Mn steel has the highest value of the proportion of equiaxed grain zone area in the three kinds of steels, whereas the 3Mn steel has the lowest value of it in the steels. Manganese has the effect of promoting the coarsening of grains. The microstructure is martensite and a little retained austenite (3.8 mass pct) in the 6Mn steel, whereas the microstructure is bainite in the 3Mn steel. The 0Mn steel is characterized by ferrite and pearlite. The mean thermal expansion coefficients of the steels are in the range from 1.0 ū 10-5 to 1.6 ū 10-5 K-1, and the determinations of mold tapers of the 6Mn and 3Mn steels can refer to low-carbon steel. Using RA <60 pct as the criterion, the third brittle temperature region of the 6Mn steel is 873 K to 1073 K (600 ░C to 800 ░C), whereas those of the 3Mn steel and the 0Mn steel are 873 K to 1123 K (600 ░C to 850 ░C) and 873 K to 1173 K (600 ░C to 900 ░C), respectively. In the 6Mn and 3Mn steels, the deformation-induced ferrite (DIF) forms in sufficient quantities cause the recovery of the ductility at the low temperature end. However, since low strains are present when straightening, sufficient quantities of DIF cannot be formed. Thus, the ductility of the 6Mn and 3Mn steels cannot be improved during the continuous casting process. Manganese has the effect of enlarging the austenite phase region and reducing the ?-ferrite phase region and ?-ferrite phase region.
High Strength Stainless Steel Properties that Affect Resistance Welding
Kanne, W.R.
This report discusses results of a study on selected high strength stainless steel alloy properties that affect resistance welding. The austenitic alloys A-286, JBK-75 (Modified A-286), 21-6-9, 22-13-5, 316 and 304L were investigated and compared. The former two are age hardenable, and the latter four obtain their strength through work hardening. Properties investigated include corrosion and its relationship to chemical cleaning, the effects of heat treatment on strength and surface condition, and the effect of mechanical properties on strength and weldability.
Thermoelectric properties of thin films of bismuth telluride electrochemically deposited on stainless steel substrates
Yi Ma; Elisabet Ahlberg; Ye Sun; Bo Brummerstedt Iversen; Anders E. C. Palmqvist
Bismuth telluride thin films have been synthesized by electrochemical deposition onto stainless steel substrates from acidic solutions. The influence of deposition variables on film composition, morphology and crystal orientation associated with the growth of the film was investigated by means of constant potential deposition and pulsed potential deposition. In-plane thermoelectric and transport properties of the electrodeposited films were measured. The
Corrosion inhibition of steel by bacteria
Hernandez, G.; Kucera, V.; Thierry, D.; Pedersen, A. (Swedish Corrosion Inst., Stockholm (Sweden)); Hermansson, M. (Univ. of Gothenburg (Sweden). Dept. of General and Marine Microbiology)
Mild steel was exposed to Pseudomonas sp. S9 or Serratia marcescens in synthetic seawater. An increase in corrosion resistance over that i natural seawater was monitored by electrochemical techniques. Biological analyses were performed to characterize the system. The inhibition effect also was observed when mild steel was coated with bacteria and then immersed in synthetic seawater. When specimens coated with bacteria were transferred to a natural seawater flow system, the inhibition effect disappeared during the first 2 weeks.
New Developments with CMnNi in High Strength Steel Weld Metals --Part B. Mechanical Properties
Cambridge, University of
New Developments with CŁMnŁNi in High Strength Steel Weld Metals -- Part B. Mechanical Properties E, Sweden. Abstract Microstructure and properties have been studied for high strength steel weld metals There has been ongoing development in high strength steel weld metals with the aim of increas- ing strength
Effect of cooling parameters on the microstructure and properties of Mo-bearing and Cr-bearing steels
NASA Astrophysics Data System (ADS)
Huo, Xiang-Dong; Li, Yu-Qian; Zhao, Yu-Tao; Zhang, Hai-Wang; Li, Zhao-Hui
To develop low-cost low carbon bainitic steel, Mo-bearing and Cr-bearing steels were melted in a vacuum induction furnace and were researched by thermal simulation and hot rolling at the laboratory. As the cooling rate increases from 0.2 to 50░C/s, the transformation temperatures of two steels lie between 650 and 400░C, and the final microstructures of them change from quasi-polygonal ferrite and granular bainite to lath bainite. Compared with cooling in air or by interrupted cooling, Mo-bearing and Cr-bearing steel plates cooled by sprayed water boast higher strength and superior toughness, for large-size islands are responsible for the poor mechanical properties. Compared to Mo, Cr is effective to isolate the bainitic reaction in low carbon steel, and the bainitic microstructure can also be obtained in Cr-bearing steel cooled at a wide range of cooling rate.
Evaluation of Microstructure and Mechanical Properties in Dissimilar Austenitic/Super Duplex Stainless Steel Joint
NASA Astrophysics Data System (ADS)
Rahmani, Mehdi; Eghlimi, Abbas; Shamanian, Morteza
To study the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super duplex (ER2594) and an austenitic (ER309LMo) stainless steel filler metal. While the austenitic weld metal had vermicular delta ferrite within austenitic matrix, super duplex stainless steel was mainly comprised of allotriomorphic grain boundary and Widmanstõtten side plate austenite morphologies in the ferrite matrix. Also the heat-affected zone of austenitic base metal comprised of large austenite grains with little amounts of ferrite, whereas a coarse-grained ferritic region was observed in the heat-affected zone of super duplex base metal. Although both welded joints showed acceptable mechanical properties, the hardness and impact strength of the weld metal produced using super duplex filler metal were found to be better than that obtained by austenitic filler metal.
Tribological properties of nitrogen implanted and boron implanted steels
K. T. Kern; K. C. Walter; A. J. Jr. Griffin; H. Kung; Y. Lu; M. Nastasi; J. R. Tesmer; S. Fayeulle
Samples of a steel with high chrome content was implanted separately with 75 keV nitrogen ions and with 75 keV boron ions. Implanted doses of each ion species were 2-, 4-, and 8 ├ 10┬╣ŌüĘ\\/cm┬▓. Retained doses were measured using resonant non-Rutherford Backscattering Spectrometry. Tribological properties were determined using a pin-on-disk test with a 6-mm diameter ruby pin with a
High-Temperature Tensile Properties of Nano-Oxide Dispersion Strengthened Ferritic Steels Produced by Mechanical Alloying and Spark Plasma Sintering
NASA Astrophysics Data System (ADS)
Boulnat, Xavier; Fabregue, Damien; Perez, Michel; Mathon, Marie-HķlĶne; de Carlan, Yann
Oxide-dispersion strengthened (ODS) ferritic steels were produced by mechanical alloying and subsequent spark plasma sintering. Very fast heating rates were used to minimize porosity when controlling grain size and precipitation of dispersoids within a compacted material. Sintering cycles performed at 1373 K (1100 ░C) induced heterogeneous, but fine grain size distribution and high density of nano-oxides. Yield strengths at room temperature and at 923 K (650 ░C) are 975 MPa and 298 MPa, respectively. Furthermore, high-temperature ductility is much increased: total strain of 28 pct at 923 K (650 ░C).
The effect of cold rolling regime on microstructure and mechanical properties of AISI 304L stainless steel
Ali Hedayati; Abbas Najafizadeh; Ahmad Kermanpur; Farnoosh Forouzan
In this paper, the effect of different thickness reductions by cold rolling on the microstructure and mechanical properties of AISI 304L austenitic stainless steel were investigated. The hot rolled steel strips were subjected to cold rolling at 0░C from 10 to 90% thickness reduction. Microstructures, strain-induced martensitic transformation and mechanical properties of the cold-rolled specimens were characterized by X-ray diffraction,
Mechanical and Thermal Properties of UltraHigh Carbon Steel Containing Aluminum
C K Syn; D R Lesuer; A Goldberg; H Tsai; O D Sherby
The properties of ultrahigh carbon steels (UHCS) are strongly influenced by aluminum additions. Hardness studies of quenched UHCS-Al alloys reveal that the temperature for the start of transformation increases with increases in aluminum content. It is shown that this change is a function of the atomic percent of solute and of the valence state when comparisons are made with UHCSs
Mechanical and Thermal Properties of UltraHigh Carbon Steel Containing Aluminum
C K Syn; D R Lesuer; A Goldberg; H C Tsai; O D Sherby
The properties of ultrahigh carbon steels (UHCS) are strongly influenced by aluminum additions. Hardness studies of quenched UHCS-Al alloys reveal that the temperature for the start of transformation increases with increases in aluminum content. It is shown that this change is a function of the atomic percent of solute and of the valence state when comparisons are made with UHCSs
Viscoelastic properties of paint films and formability in deep drawing of pre-painted steel sheets
Kohei Ueda; Hiroshi Kanai; Takeshi Amari
Damage of paint films on pre-painted steel sheets (PCMs) in a deep drawing process is influenced by the mechanical properties of the paint films. We reported that paint films, which exhibit high elongation and low elastic strain energy (ESE) have good formability in a deep drawing process. However, examination of the paint films from a rheological viewpoint is needed for
Cyclic Material Properties Test to Determine Hardening/Softening Characteristics of HY-80 Steel
S.C. Hodge; J.M. Minicucci; T.F. Trimble
The Cyclic Material Properties Test was structured to obtain and provide experimental data for determining cyclic hardening/softening characteristics of HY-80 steel. The inelastic strain history data generated by this test program and the resulting cyclic stress-strain curve will be used to enhance material models in the finite element codes used to perform nonlinear elastic-plastic analysis.
Effect of hydrogen on the mechanical properties of steels with diffusion coatings
Yu. N. Nikiforchin; N. I. Dydyn; A. L. Bichuya; A. S. Osered'ko; V. F. Shatinskii
The purpose of this work was to determine the possibility of using diffusion coatings to prevent the harmful effect of hydrogen on the mechanical properties. The experiments were made with samples of steel 20 with coatings obtained by diffusion saturation with chromium, aluminum, and both elements at the same time. The phase composition of the coatings, concentration of the diffusing
A review of some effects of helium on charpy impact properties of ferritic\\/martensitic steels
D. S. Gelles; G. L. Hankin; M. L. Hamilton
To evaluate the effect of helium on Charpy impact properties of ferritic\\/martensitic steels, two approaches are reviewed: quantification of results of earlier tests performed by other researchers on specimens irradiated in reactors with very different neutron spectra, and evaluation of isotopic tailoring experiments. Data analysis can show that if the differences in reactor response are indeed due to helium effects,
Effect of elevated temperature on the composition, structure, and mechanical properties of diffusion chromized steel
Osintsev, V.D.
The author studies the effect of operating temperature for equipment in contact sections of sulfuric acid workshops on the structure and mechanical properties of the chromized coatings and core of chromized articles. The ferrite lattice spacing was determined in a DRON-0.5 diffractometer according to the line in copper K /sub alpha/ radiation exposure was carried out after layer-by-layer anodic etching of the coating in an aqueous solution. It was shown that diffusion chromizing may lead to a reduction in strength properties compared with those of unchromized steel. As a base for chromized articles intended for operation at temperatures up to 475/sup 0/C it is desirable to use steels 09G2 or 09G25, or for operation at temperatures up to 540/sup 0/C, steels 12KhM and 12MKh.
Tensile and creep properties of reduced activation ferritic-martensitic steel for fusion energy application
NASA Astrophysics Data System (ADS)
Mathew, M. D.; Vanaja, J.; Laha, K.; Varaprasad Reddy, G.; Chandravathi, K. S.; Bhanu Sankara Rao, K.
Tensile and creep properties of a reduced activation ferritic-martensitic (RAFM) steel for Indian Test Blanket Module (TBM) to be tested in ITER have been evaluated. The tensile strength was found to decrease with temperature; the rate of decrease being slower in the intermediate temperature range of 450-650 K. Tensile ductility of the steel decreased with increase in temperature up to 650 K, followed by a rapid increase beyond 650 K. Creep studies have been carried out at 773, 823 and 873 K over a stress range of 100-300 MPa. The variation of minimum creep rate with applied stress followed a power law, ? = A? n. The ' n' value decreased with increase in temperature. The creep rupture life was found to relate inversely with minimum creep rate through the Monkman-Grant relation, t r Ę ? = constant. The tensile and creep properties of the steel were comparable with those of Eurofer 97.
Fracture toughness properties of welded stainless steels for tritium service
Morgan, M.
Studies to determine tritium exposure effects on the properties of welded steels are being conducted. In this investigation, the effects of tritium and decay helium on the fracture toughness properties of high-energy-rate-forged (HERF) Incoloy 903 were. Fracture toughness measurements were conducted for tritium-exposed samples in the as-forged condition and compared with welded samples. Tritium-exposed HERF Incoloy 903 had fracture toughness values that were 33% lower than those for unexposed HERF Incoloy 903. Tritium-exposed welded samples had fracture toughness values that were just 8% of the unexposed HERF alloys and 28% of unexposed welded alloys.
Mechanical and tribological properties of AISI 304 stainless steel nitrided by glow discharge compared to ion implantation and plasma immersion ion implantation
NASA Astrophysics Data System (ADS)
Foerster, C. E.; Serbena, F. C.; da Silva, S. L. R.; Lepienski, C. M.; Siqueira, C. J. de M.; Ueda, M.
Results about mechanical and tribological behavior of AISI 304 stainless steel nitrided by three different ion beam processes - glow discharge (GD), ion implantation (II) and plasma immersion ion implantation (PI3) are reported. Expanded austenite ?N and nitrides phases (Fe2+xN, ??-Fe4N and Cr-N) were identified as a function of nitriding conditions. Hardness (H) and elastic modulus (E) profiles were obtained by instrumented penetration. The hardness reached values as high as 21 GPa by PI3. Tribological behavior was studied by reciprocating sliding tests with a WC (Co) ball at room temperature (RT) in dry condition. Different wear regimes were identified in the friction coefficient profiles. The profile form and the running-in distance are strongly dependent on the nitriding process. Adhesive and abrasive wear components can be inferred from these friction profiles. Hardness and tribological performance, after the nitriding processes, are discussed in terms of surface microstructure.
Mechanical and physical properties of irradiated type 348 stainless steel
Beeston, J.M.
A type 348 stainless steel in-pile tube irradiated to a fluence of 3 x 10/sup 22/ n/cm/sup 2/, E > 1 MeV (57 dpa), was destructively examined. The service had resulted in a maximum total creep of 1.8% at the high fluence. The metal temperature ranged between 623 and 652/sup 0/K, hence the thermal creep portion of the total was negligible. Total creep was greater than had been anticipated from creep data for austenitic stainless steels irradiated in other reactors. The objectives of the destructive examination were to determine the service-induced changes of mechanical and physical properties, and to assess the possibility of adverse effects of both these changes and the greater total creep on the prospective service life of other tubes.
The dependence of complex alloyed steel properties on quenching and tempering conditions
Vinokur, B.B. [Inst. of Casting Problems, Kiev (Ukraine); Vinokur, A. [E.O. Paton Inst. of Electrical Welding, Kiev (Ukraine); Shtessel, V.E. [Drexel Univ., Philadelphia, PA (United States). Materials Engineering Dept.
Morphology and structure of carbides in complex alloyed steels largely differ from those of carbides in the ordinary steels, mainly because complex alloyed steels contain more carbide forming elements. These elements vary the stability of carbides and their dissolution temperatures in austenite. The carbides in complex alloyed steels dissolve in austenite at higher temperatures and require longer dissolution times as compared to the ordinary steels. The level of carbide dissolution determines mechanical properties, sensibility to brittle fracture, hardenability, secondary hardness, etc. These characteristics develop during tempering and depend on the phase composition and the matrix alloying level. Mechanical properties, such as the ultimate tensile strength {sigma}{sub u}, the yield strength {sigma}{sub y}, the elongation {delta}, and the reduction of area {psi}, were tested on specimens with 10-mm diameters and 50-mm lengths. The impact toughness {alpha}{sub 1} was tested on Menage`s specimens with a cross section of 10 x 10 mm, depth of notch 2 mm, and radius of notch 1 mm. All specimens were heated in synthetic slag to protect the surface from oxidation and decarburization. The hardness was tested using the Vickers method. The hardenability was obtained with Jomini`s method on specimens 25 mm in diameter and 100 mm in length. The degree of carbide dissolution in austenite was investigated by weighing the carbide sediment, i.e., the metallic matrix was dissolved electrochemically, and the carbides precipitated to the bottom.
Effects of solution treatment and test temperature on tensile properties of high strength high Mn austenitic steels
W. Bleck; A. Schwedt; J. Mayer
Tensile properties of high strength high Mn austenitic Fe-26.5%Mn-3.6%Al-2.2%Si-0.38%C-0.005%B and Fe-18.9%Mn-0.62%C-0.02%Ti-0.005%B-0.11%N\\u000a steels were investigated after different solution treatments. The results show that the solution treatment has a significant\\u000a influence on microstructure and mechanical properties of the investigated steels. By appropriate solution treatment the product\\u000a of tensile strength (Rm) and total elongation (A50) of the hot rolled steel can be improved
Effect of heat treatment in magnetic field on the mechanical properties of carbon steels
P. I. Rusin; V. N. Pustovoit; S. A. Grishin
We investigated the changes in the mechanical properties of carbon steels after iso- thermal treatment in the temperature range of the pearlitic transformation under the influ- ence of magnetic field. The experiments were made with samples of steels 45 and UIOA from commercial heats. Statistically significant changes in the parameters of the structure of isothermal decomposition products in carbon steels
Investigation on mechanical properties, durability and micro-structural development of steel slag blended cements
Tongsheng Zhang; Qijun Yu; Jiangxiong Wei; Jianxin Li
To improve the properties of steel slag blended cements, a chemical activator was added into blended cements, the mechanical\\u000a properties and durability of steel slag blended cements were investigated. The results show that steel slag in blended cement\\u000a pastes presents low hydraulic activity and makes practically no contribution to strength development. After the addition of\\u000a chemical activator, the mechanical properties
Effect of d-ferrite on impact properties of supermartensitic stainless steel
Cambridge, University of
affects the impact properties of the HAZ. Charpy impact testing has been chosen to evaluate the impactEffect of d-ferrite on impact properties of supermartensitic stainless steel heat affected zones D of the presence of non-equilibrium d-ferrite on the impact properties of a supermartensitic stainless steel
High-Mn steel weldment mechanical properties at 4 K
Chan, J.W.; Sunwoo, A.J.; Morris, J.W. Jr.
Advanced high-field superconducting magnets of the next generation of magnetic confinement fusion devices will require structural alloys with high yield strength and high toughness at cryogenic temperatures. Commercially available alloys used in the current generation of magnets, such as 300 series stainless steels, do not have the required properties. N-strengthened, high-Mn alloys meet base plate requirements in the as-rolled condition. However, the property changes associated with weld microstructural and chemical changes in these alloys have not been well characterized. In this work welding induced cryogenic mechanical property changes of an 18Mn-16Cr-5Ni-0.2N alloy are correlated with as-solidified weld microstructures and chemistries. 30 refs., 12 figs., 3 tabs.
Effect of thermal aging on mechanical properties of cast stainless steels
Chopra, O.K.
A procedure and correlations are presented for predicting mechanical properties of cast stainless steels in service at temperatures <450{degrees}C from known material information. The ``saturation`` fracture properties of a cast stainless steel, i.e., the minimum values that would be achieved for the material after long-term service, are estimated from the chemical composition of the steel. Fracture properties as a function of time and temperature of service are estimated from the kinetics of embrittlement, which are also determined from chemical composition. The correlations successfully predict fracture toughness, Charpy-impact, and tensile properties of cast stainless steels from the Shippingport-, Ringhals-, and Gundremmingen-reactor components.
Influence of Zn Coating on Interfacial Reactions and Mechanical Properties During Laser Welding-Brazing of Mg to Steel
NASA Astrophysics Data System (ADS)
Li, Liqun; Tan, Caiwang; Chen, Yanbin; Guo, Wei; Hu, Xinbin
To investigate the influence of Zn coating on the joining of magnesium alloy AZ31 to Zn-coated steel, dissimilar metal joining both with and without Zn coating was performed by the laser welding-brazing (LWB) process. Welding characteristics including joint appearance, identification of interfacial reaction layers, and mechanical properties were comparatively studied. The results indicated that the presence of Zn coating promoted the wetting of liquid filler wire on the steel substrate. Heterogeneous interfacial reaction layers formed along the interface between the Mg alloy and Zn-coated steel, whereas no distinct reaction layer and increased concentration of Al were identified at the interface between the Mg alloy and noncoated steel. The maximum tensile-shear strength of Mg/steel lap joint with Zn coating reached 180 N/mm, which was slightly higher than that achieved without Zn coating (160 N/mm). Failure of joint in both cases occurred at the interface; however, the fracture mode was found to differ. For Zn-coated steel, the crack propagated along the Mg-Zn reaction layer and Fe-Al phase, with little Mg-Zn reaction phases remaining on the steel side. As for noncoated steel, some remnants of the seam adhered to the steel substrate.
Effects of irradiation on the fracture properties of stainless steel weld overlay cladding
Haggag, F.M.; Corwin, W.R.; Nanstad, R.K.
Stainless steel weld overlay cladding was fabricated using the submerged arc, single-wire, oscillating-electrode, and the three-wire, series-arc methods. Three layers of cladding were applied to a pressure vessel plate to provide adequate thickness for fabrication of test specimens, and irradiations were conducted at temperatures and to fluences relevant to power reactor operation. For the first single-wire method, the first layer was type 309, and the upper two layers were type 308 stainless steel. The type 309 was diluted considerably by excessive melting of the base plate. The three-wire method used various combinations of types 308, 309, and 304 stainless steel weld wires, and produced a highly controlled weld chemistry, microstructure, and fracture properties in all three layers of the weld. 14 refs., 15 figs., 4 tabs.
Improved mechanical properties of A 508 class 3 steel for nuclear pressure vessel through steelmaking
Kim, J.T.; Kwon, H.K.; Kim, K.C.; Kim, J.M. [Korea Heavy Industries and Construction Co., Ltd., Changwon (Korea, Republic of)
The present work is concerned with the steelmaking practices which improve the mechanical properties of the A 508 class 3 steel for reactor pressure vessel. Three kinds of steelmaking practices were applied to manufacture the forged heavy wall shell for reactor pressure vessel, that is, the vacuum carbon deoxidation (VCD), modified VCD containing aluminum and silicon-killing. The segregation of the chemical elements through the thickness was quite small so that the variations of the tensile properties at room temperature were small and the anisotropy of the impact properties was hardly observed regardless of the steelmaking practices. The Charpy V-notch impact properties and the reference nil-ductile transition temperature by drop weight test were significantly improved by the modified VCD and silicon-killing as compared with those of the steel by VCD. Moreover, the plane strain fracture toughness values of the materials by modified VCD and silicon-killing practices was much higher than those of the steel by VCD. These were resulted from the fining of austenite grain size. It was observed that the grain size was below 20 {micro}m (ASTM No. 8.5) when using the modified VCD and silicon-killing, compared to 50 {micro}m (ASTM No. 7.0) when using VCD.
Chemical and Mechanical Properties of ZDDP Antiwear Films on Steel and Thermal Spray Coatings Studied by XANES Spectroscopy and Nanoindentation Techniques
Mark A. Nicholls; Than Do; Peter R. Norton; G. Michael Bancroft; Masoud Kasrai; T. Weston Capehart; Yang-Tse Cheng; Thomas Perry
X-ray Absorption Near Edge Structure (XANES) has been used to characterize the chemistry of tribochemical wear pads generated from a paraffinic base oil with a zinc-dialkyl-dithiophosphate additive on steel surfaces and high-velocity oxygen fuel (HVOF) thermal spray coatings. The phosphorus K- and L- edge XANES spectra show that the tribofilms formed on steel and the HVOF coatings have the same
Correlations between Nanoindentation Hardness and Macroscopic Mechanical Properties in DP980 Steels
Taylor, Mark D.; Choi, Kyoo Sil; Sun, Xin; Matlock, David K.; Packard, Corrine; Xu, Le; Barlat, Frederic
Multiphase advanced high strength steels (AHSS) are being increasingly used in the automotive industry due to their low cost, good availability and excellent combination of strength and ductility. There is a keen interest from the automotive and steel industry for more fundamental understandings on the key microstructure features influencing the macroscopic properties, i.e., tensile properties, hole-expansion ratio and localized formability of AHSS. In this study, the micro- and macro-level properties for eight commercial DP980 steels are first characterized and quantified with various experimental methods. Correlations between macroscopic-level properties and relationships between various micro- and macro- properties for these steels are then established based on the experimental measurements. It is found that, despite their differences in their chemistry, processing parameters and sheet thickness, the eight DP980 steels do have common microstructural level properties governing their specific macroscopic properties in terms of strength, elongation and hole expansion performance.
Effect of prior cold work on creep properties of a titanium modified austenitic stainless steel
NASA Astrophysics Data System (ADS)
Vijayanand, V. D.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Laha, K.; Mathew, M. D.
Prior cold worked (PCW) titanium-modified 14Cr-15Ni austenitic stainless steel (SS) is used as a core-structural material in fast breeder reactor because of its superior creep strength and resistance to void swelling. In this study, the influence of PCW in the range of 16-24% on creep properties of IFAC-1 SS, a titanium modified 14Cr-15Ni austenitic SS, at 923 K and 973 K has been investigated. It was found that PCW has no appreciable effect on the creep deformation rate of the steel at both the test temperatures; creep rupture life increased with PCW at 923 K and remained rather unaffected at 973 K. The dislocation structure along with precipitation in the PCW steel was found to change appreciably depending on creep testing conditions. A well-defined dislocation substructure was observed on creep testing at 923 K; a well-annealed microstructure with evidences of recrystallization was observed on creep testing at 973 K. Creep rupture life of the steel increased with the increase in PCW at 923 K. This has been attributed to the partial retention of prior cold work induced dislocations which facilitated the extensive precipitation of secondary Ti(C,N) particles on the stable dislocation substructure. Creep rupture life of the steel did not vary with PCW at 973 K due to softening by recrystallization and absence of secondary Ti(C,N).
Microstructure and mechanical properties of laser melting deposited 1Cr12Ni2WMoVNb steel
Y. D. Wang; H. B. Tang; Y. L. Fang; H. M. Wang
1Cr12Ni2WMoVNb martensitic stainless steel was fabricated by laser melting deposition (LMD) process. Microstructure was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Vickers microhardness and room-temperature tensile properties were evaluated as well. Results indicate that the laser deposited steel has a fine well-aligned dendritic structure with a primary dendrite arm spacing of approximately 13?m.
Effect of surface nanocrystallization on the tribological properties of 1Cr18Ni9Ti stainless steel
Guo-zheng Ma; Bin-shi Xu; Hai-dou Wang; Hong-juan Si; Da-xiang Yang
Surface nanocrystallization of 1Cr18Ni9Ti austenite stainless steel was conducted by the supersonic fine particles bombarding (SFPB) technique. The friction coefficients and wear losses in air and vacuum were tested to analyse the effect of surface nanocrystallization on the tribological properties of 1Cr18Ni9Ti steel. The results show that the microstructure of the surface layer was refined into nano-grains successfully by SFPB
Effect of thermomechanical treatment conditions on the structure and properties of low-carbon weldable steel
NASA Astrophysics Data System (ADS)
Schastlivtsev, V. M.; Tabatchikova, T. I.; Yakovleva, I. L.; Klyueva, S. Yu.
A correlation is found between the structure and mechanical properties of rolled steel X90 sheets produced by various schemes of thermomechanical hardening: quenching from the rolling temperature followed by high-temperature tempering and two-stage thermomechanical treatment (TMT). Two-stage TMT is shown to have substantial advantages over quenching from the rolling temperature, which is related to the formation of a highly dispersed subgrain bainite structure.
Estimation of mechanical properties of cast stainless steels during thermal aging in LWR systems
Chopra, O.K.
A procedure and correlations are presented for assessing thermal embrittlement and predicting mechanical properties of cast stainless steels under light water reactor operating conditions from known material information. The ``saturation`` fracture toughness of a cast stainless steel, i.e., the minimum value that would be achieved for the material after long-term service, is estimated from the chemical composition of the steel. Fracture properties as a function of time and temperature of service are estimated from the kinetics of embrittlement, which are also determined from chemical composition. The correlations successfully predict fracture toughness, Charpy-impact, and tensile properties of cast stainless steels from the Shippingport, Ringhals, and KRB reactors.
Improved tribology of tool steel by zirconium ion implantation
Akbas, N.; Oztarhan, A.; Monteiro, O.R.; Brown, I.G.
AISI D3 tool steel was ion implanted with zirconium and the improvement in surface tribological properties investigated. The Zr ion implantation was done using a metal vapor vacuum arc broad-beam ion source, with a mean ion energy of 130 keV and at doses of 3.6 x 10(sup 16), 5 x 10(sup 16) and 1 x 10(sup 17) ions/cm2. Wear, friction and hardness of the implanted samples were measured and compared to the performance of unimplanted steel. The wear resistance was increased by about a factor of two, the friction remained about the same or was possibly increased by a small amount, and the hardness was improved by a factor of five or more by the ion implantation. We also investigated the effect on the Zr implantation profile of the multi-component energy distribution of the ion beam used here.
Effect of rust on the wettability of steel by water
Lu, W.; Chung, D.D.L. [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.] [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.
Rust, as formed on steel by immersion of low-carbon steel in water, was found to improve the wettability of steel by water. The advancing contact angle decreased from 87{degree} to 32{degree}, and the receding contact angle decreased from 81{degree} to 29{degree}. Cleansing of steel by acetone also helped improve the wettability, but the advancing angle only decreased from 87{degree} to 73{degree}, and the receding angle only decreased from 81{degree} to 41{degree}.
Titanium effect on the microstructure and properties of laminated high boron steel plates
NASA Astrophysics Data System (ADS)
Yuan, Lin-lin; Han, Jing-tao; Liu, Jing; Wei, Dong-bin; Abathun, Mehari Zelalem
High-boron steel is an important material used for thermal neutron shielding. The appropriate amount of added boron must be determined because excessive boron may deteriorate the steel's workability. A uniform microstructure can be formed by adding titanium to boron steel. In this study, casting and hot rolling were used to fabricate laminated high-boron steel plates whose cores contained 2.25wt% boron and 0wt%-7.9wt% titanium. The effects of titanium content and hot-rolling and heat-treatment processes on the microstructure and properties of the laminated plates were studied. The results indicated that the optimum titanium content was 5.7wt% when the boron content was 2.25wt%, and that the best overall properties were obtained after heat treatment at 1100░C for 4 h. The tensile strength, yield strength, and elongation at the specified temperature and holding time were as high as 526.88 MPa, 219.36 MPa, and 29%, respectively.
Microstructure and mechanical properties of duplex stainless steel subjected to hydrostatic extrusion
Maj, P., E-mail: email@example.com [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wo?oska 141, 02-507 Warsaw (Poland); Adamczyk-Cie?lak, B.; Mizera, J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wo?oska 141, 02-507 Warsaw (Poland); Pachla, W. [High Pressure Research Center, Polish Academy of Sciences, Soko?owska 29, 01-142 Warsaw (Poland); Kurzyd?owski, K.J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wo?oska 141, 02-507 Warsaw (Poland)
The nanostructure and mechanical properties of ferritic-austenitic duplex stainless steel subjected to hydrostatic extrusion were examined. The refinement of the structure in the initial state and in the two deformation states (? = 1.4 and ? = 3.8) was observed in an optical microscope (OM) and a transmission electron microscope (TEM). The results indicate that the structure evolved from microcrystalline with a grain size of about 4 ?m to nanocrystalline with a grain size of about 150 nm in ferrite and 70 nm in austenite. The material was characterized mechanically by tensile tests performed in the two deformation states. The ultimate strength appeared to increase significantly compared to that in the initial deformation stages, which can be attributed to the grain refinement and plastic deformation. The heterogeneity observed in microregions results from the dual-phase structure of the steel. The results indicate that hydrostatic extrusion is a highly potential technology suitable for improving the properties of duplex steels. - Highlights: Ģ Duplex stainless steel was hydro extruded to a total strain of 3.8 Ģ After the last stage of deformation heterogeneous structure was obtained in the material Ģ As a result of stresses non-diffusive transformation ???Æ occurred in the material Ģ Nanometric (sub)grains were obtained in the austenite regions.
Recent Developments in On-Line Assessment of Steel Strip Properties
Meilland, P. [Arcelor Research, Voie Romaine, 57280 Maizieres-les-Metz (France); Kroos, J. [Quality Management, Salzgitter A.G., 38223 Salzgitter (Germany); Buchholtz, O. W. [WKZ-Auto, ThyssenKrupp Stahl, Kaiser-Wilhelm Strasse 100, 47166 Duisburg (Germany); Hartmann, H.-J. [FQZ-Brandenburg, IndustriePark EKO Strasse 20, 15890 Eisenhuetttenstadt (Germany)
On-line non-destructive assessment of steel strip properties is a subject of growing interest amongst European manufacturers, as it provides information all along the products length, without slowing down the production. Arcelor, Salzgitter and TKS recently undertook a collective effort to assess the performance of 3 systems for flat carbon steel strips mechanical properties at the exit of galvanizing lines.
Todd M. Osman; C. Isaac Garcia
The relationships between metallurgy and the production of niobium-bearing interstitial-free steels are reviewed. Processing-structure-property relationships are discussed, beginning with modern steelmaking processes and continuing through subsequent thermomechanical processing. Interstitial-free stabilization, microstructural development, and mechanical properties of niobium -bearing interstitial-free steels are reviewed as well as the influence of niobium on coating characteristics.
Effect of Nitrogen on Stacking Fault Formation Probability and Mechanical Properties of Twinning-Induced Plasticity Steels
B. X. Huang; X. D. Wang; L. Wang; Y. H. Rong
Twinning induced plasticity (TWIP) steels containing nitrogen as the interstitial alloying element were designed, and the effects of N and Al on stacking fault energy (SFE), microstructure, and mechanical properties were investigated by using X-ray diffraction and transmission electron microscopy to determine the stacking fault formation probability. In addition, the microstructure and mechanical properties have been characterized. The results indicate
Structure and mechanical and corrosion properties of new high-nitrogen Cr-Mn steels containing molybdenum
NASA Astrophysics Data System (ADS)
Berezovskaya, V. V.; Savrai, R. A.; Merkushkin, E. A.; Makarov, A. V.
The structure, mechanical properties, and pitting corrosion of nickel-free high-nitrogen (0.8% N) austenitic 06Kh18AG19M2 and 07Kh16AG13M3 steels have been studied in various structural states obtained after hot deformation, quenching, and tempering at 300 and 500░C. Both steels are shown to be resistant to the ? ? ? and ? ? ? martensite transformations irrespective of the decomposition of a ? solid solution (06Kh18AG19M2 steel). Austenite of the steel with 19 wt % Mn shows lower resistance to recrystallization, which provides its higher plasticity (?5) and fracture toughness at a lower strength as compared to the steel with 13 wt % Mn. Electrochemical studies of the steels tempered at 300 and 500░C show that they are in a stable passive state during tests in a 3.5% NaCl solution and have high pitting resistance up to a potential E pf = 1.3-1.4 V, which is higher than that in 12Kh18N10T steel. In the quenched state, the passive state is instable but pitting formation potentials E pf retain their values. In all steels under study, pitting is shown to form predominantly along the grain boundaries of nonrecrystallized austenite. The lowest pitting resistance is demonstrated by the structure with a double grain boundary network that results from incomplete recrystallization at 1100░C and from the existence of initial and recrystallized austenite in the 07Kh16AG13M3 steel. To obtain a set of high mechanical and corrosion properties under given rolling conditions (1200-1150░C), annealing of the steels at temperatures no less than 1150░C (for 1 h) with water quenching and tempering at 500░C for 2 h are recommended.
Separability property and ? pl factor in ASTM A387Gr22 steel plate
A. N. Cassanelli; R. Cocco; L. A. de Vedia
In this work the possibility of obtaining the function G(b\\/W) from the variable separability property to calculate ?pl factor following the methodology proposed by Sharobeam and Landes using a deformation function H with total displacement was studied. The material employed was an ASTM A387-Gr22 steel plate and standard ASTM SE(B) and C(T) geometries were used for the test pieces with
Clay and DOPA containing polyelectrolyte multilayer film for imparting anticorrosion properties to galvanized steel.
Faure, Emilie; Halusiak, Emilie; Farina, Fabrice; Giamblanco, Nicoletta; Motte, Cķcile; Poelman, Mireille; Archambeau, Catherine; Van de Weerdt, Cķcile; Martial, Joseph; Jķr¶me, Christine; Duwez, Anne-Sophie; Detrembleur, Christophe
A facile and green approach is developed to impart remarkable protection against corrosion to galvanized steel. A protecting multilayer film is formed by alternating the deposition of a polycation bearing catechol groups, used as corrosion inhibitors, with clay that induces barrier properties. This coating does not affect the esthetical aspect of the surface and does not release any toxic molecules in the environment. PMID:22200075
Low cycle fatigue properties of 8Cr¢2WVTa ferritic steel at elevated temperatures
T. Ishii; K. Fukaya; Y. Nishiyama; M. Suzuki; M. Eto
The effects of test temperature and tension holding on the fatigue properties of reduced activation ferritic\\/martensitic 8Cr¢2WVTa (F-82H) steel were investigated by conducting low cycle fatigue tests at temperatures ranging from RT to 650░C under the axial strain-controlled condition with strains ranging from 0.5% to 2.0%. Fatigue life data were formulated as strain-life equations. A large reduction in the fatigue
Effects of neutron irradiation on tensile properties of oxide dispersion strengthened (ODS) steel claddings
NASA Astrophysics Data System (ADS)
Yano, Y.; Ogawa, R.; Yamashita, S.; Ohtsuka, S.; Kaito, T.; Akasaka, N.; Inoue, M.; Yoshitake, T.; Tanaka, K.
The effects of fast neutron irradiation on ring tensile properties of oxide dispersion strengthened (ODS) steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the material irradiation rig at temperatures between 693 and 1108 K to fast neutron doses ranging from 16 to 33 dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures. The experimental results showed that there was no significant change in tensile strengths after neutron irradiation below 923 K, but the tensile strengths at neutron irradiation above 1023 K up to 33 dpa were decreased by about 20%. On the other hand, uniform elongation after irradiation was more than 2% at all irradiation conditions. The ring tensile properties of these ODS claddings remained excellent within these irradiation conditions compared with conventional 11Cr ferritic/martensitic steel (PNC-FMS) claddings.
1D subsurface electromagnetic fields excited by energized steel casing
Torres-VerdĒn, Carlos
- length thin wire of piecewise-constant electric conductivity and magnetic permeability. The steel1D subsurface electromagnetic fields excited by energized steel casing Wei Yang1 , Carlos Torres the possibility of enabling steel-cased wells as galvanic sources to detect and quantify spatial variations
Mechanical properties and microstructure evolution of CLAM Steel in tube fabrication and test blanket module assembly
NASA Astrophysics Data System (ADS)
Huang, Bo; Huang, Qunying; Li, Yanfen; Li, Chunjing; Wu, Qingsheng; FDS Team
The first wall of the China dual functional lithium lead-test blanket module (DFLL-TBM) will be assembled with China low activation martensitic (CLAM) steel rectangular tubes and plates by hot isostatic pressing (HIP) - diffusion welding. The objective of this study is to evaluate CLAM rectangular tubes and investigate mechanical property and microstructure evolution of CLAM steel in tube fabrication and TBM assembly. In this work, CLAM rectangular tubes with lengths of 1500 mm were fabricated, and the dimensional accuracy met the requirement for HIP joining. In the tube fabrication process, the CLAM steel was annealed to improve its ductility. In addition, the anisotropy in mechanical properties and microstructure introduced by tube rolling was eliminated according to the simulation of HIP heat treatment in TBM preparation. The tensile strength of the CLAM tubes with final heat treatment was slightly higher than that of CLAM steel with the published standard heat treatment, while the total elongation was reduced. This revealed that a post-HIP heat treatment was required before the final heat treatment. An annealing treatment at 1253 K transformed martensite to ferrite, decreased the tensile strength, and increase the ductility; Rolling deformation introduced microstructural anisotropy, increased the Vickers hardness, and created an inhomogeneous hardness distribution; A simulated HIP heat treatment schedule removed these differences in hardness and tensile strength due to the anisotropy; The tensile strength of CLAM tube material given the published standard heat treatment (with the simulated HIP heat treatment) was higher than that of previously published CLAM steel results and the elongation was reduced. Therefore, a post-HIP heat treatment for CLAM tube material appears to be required before applying a final heat treatment based on the prior standard heat treatment in order to preserve the overall tensile elongation.
Elevated temperature mechanical properties of a reactor pressure vessel steel
NASA Astrophysics Data System (ADS)
McCoy, H. E.; Rittenhouse, P. L.
A testing program is in progress to define the tensile and creep properties of SA533 Grade B Class 1 steel at temperatures from 371 to 538 ░C. The overall objective is to provide the data necessary to obtain ASME Code approval for use of this material for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) vessel during short-term temperature excursions above 371 ░C. Testing and evaluation involve three heats of base metal, two submerged arc welds, and a shielded metal arc weld. The creep strengths of the base metal heats and the weldments were found to be equivalent; the weld metal itself is slightly stronger. The data obtained indicate that stress to produce 1% strain will likely be the controlling factor in setting the allowable stresses for design.
Morgan, M.
Tritium reservoirs are constructed from welded stainless steel forgings. While these steels are highly resistant to the embrittling effects of hydrogen isotopes and helium from tritium decay; they are not immune. Tritium embrittlement is an enhanced form of hydrogen embrittlement because of the presence of helium-3 from tritium decay which nucleates as nanometer-sized bubbles on dislocations, grain boundaries, and other microstructural defects. Steels with decay helium bubble microstructures are hardened and less able to deform plastically and become more susceptible to embrittlement by hydrogen and its isotopes. Ductility, elongation-to-failure, and fracture toughness are reduced by exposures to tritium and the reductions increase with time as helium-3 builds into the material from tritium permeation and radioactive decay. Material and forging specifications have been developed for optimal material compatibility with tritium. These specifications cover composition, mechanical properties, and select microstructural characteristics like grain size, flow-line orientation, inclusion content, and ferrite distribution. For many years, the forming process of choice for reservoir manufacturing was high-energy-rate forging (HERF), principally because the DOE forging facility owned only HERF hammers. Today, some reservoir forgings are being made that use a conventional, more common process known as press forging (PF or CF). One of the chief differences between the two forging processes is strain rate: Conventional hydraulic or mechanical forging presses deform the metal at 4-8 ft/s, about ten-fold slower than the HERF process. The material specifications continue to provide successful stockpile performance by ensuring that the two forging processes produce similar reservoir microstructures. While long-term life storage tests have demonstrated the general tritium compatibility of tritium reservoirs, fracture-toughness properties of both conventionally forged and high-energy-rate forged are needed for designing and establishing longer tritium-reservoir lifetimes, ranking materials, and, potentially, for qualifying new forging vendors or processes. Measurements on the effects of tritium and decay helium on the fracture toughness properties of CF stainless steels having similar composition, grain size, and mechanical properties to previously studied HERF steels are needed and have not been conducted until now. The compatibility of stainless steel welds with tritium represents another concern for long-term reservoir performance. Weldments have not been well-characterized with respect to tritium embrittlement, although a recent study was completed on the effect of tritium and decay helium on the fracture toughness properties of Type 304L weldments. This study expands the characterization of weldments through measurements of tritium and decay helium effects on the fracture toughness properties of Type 21-6-9 stainless steel. The purpose of this study was to measure and compare the fracture toughness properties of Type 21-6-9 stainless steel for conventional forgings and weldments in the non-charged, hydrogen-charged and tritium-charged-and-aged conditions.
Adsorption properties and inhibition of mild steel corrosion in 15% HCl by 3-((1H-indol-3-yl)(4-methoxyphenyl)methyl)-1H-indole:electrochemical study
NASA Astrophysics Data System (ADS)
Behera, Debasis; Kumar, Sushil; Sinha, Rajesh Ranjan; Yadav, Mahendra
The inhibiting effect of 3-((1H-indol-3-yl)(4-methoxyphenyl)methyl)-1H-indole (IMMI) on the corrosion of mild steel (MS) in 15% HCl solution has been studied by using potentiodynamic polarization technique. The polarization data revealed that IMMI acts as a mixed type inhibitor for mild steel in acid solution.. The adsorption of the inhibitors on the mild steel surface was found to obey Langmuir's adsorption isotherm. Inhibition efficiency was found to be greater than 95% and inhibition is governed by both physical adsorption and chemisorption mechanism.
Microstructures and wear properties of TiN-based cermet coating deposited on 1Cr18Ni9Ti stainless steel by electrospark process
X. Li; D. Q. Sun; X. Y. Zheng; Z. A. Ren
A simple and effective surface treatment technique, electrospark deposition (ESD), has been successfully applied to deposit TiN-based cermet coating on stainless steel substrate. The nitrided coating had an average thickness of about 30?m and formed metallurgical bonding with the substrate. The microstructure of the coating was mainly composed of TiN phase and ferrite (?-FeCr) phase. Its microhardness reached 889HV. The
Basic properties of steel plant dust and technological properties of direct reduction
Xue-Feng She; Jing-Song Wang; Qing-Guo Xue; Yin-Gui Ding; Sheng-Sheng Zhang; Jie-Ji Dong; Hui Zeng
Basic physicochemical properties of the dust from Laiwu Iron and Steel Co. Ltd. were studied. It is found that C, Zn, K, Na,\\u000a etc. exist in the fabric filter dust, off gas (OG) sludge, fine ash in converter, and electrical field dust in sinter. Among\\u000a these, OG sludge gives the finest particle, more than 90% of which is less than
Improving Joint Properties of Friction Welded Joint of High Tensile Steel
NASA Astrophysics Data System (ADS)
Kimura, Masaaki; Kusaka, Masahiro; Seo, Kenji; Fuji, Akiyoshi
This report describes the improvements in the joint properties of friction welded joint of 780MPa class high tensile steel. Welded joint made by a continuous drive friction welding machine, the conventional method, had not obtained 100% joint efficiency despite applying forge pressure. This was due to the softening of the welded interface zone for heat input during braking times. Therefore, we developed a continuous drive friction welding machine with an electromagnetic clutch to prevent heat input during braking time. We proposed the process as ōThe Low Heat Input Friction Welding Method (the LHI method).ö In this case, the joint had the same tensile strength as the base metal at friction time when the friction torque reached the initial peak torque. That is, the welded joint obtained 100% joint efficiency by using only the friction stage up to the initial peak torque without the forge (upsetting) stage, despite the existence of a slightly softened region adjacent to the welded interface. Furthermore, the softened region was hardly generated when this joint was made by applying forge pressure at the initial peak torque. In conclusion, a welded joint of high tensile steel made by only the friction stage of the LHI method had excellent joint properties. The LHI method has a lot of advantages for joining such materials as super fine grain steel with which conventional fusion welding processes have difficulty.
Structure and properties of steel R6M5 after thermomechanical treatment
I. K. Kupalova
A positive effect of low-temperature thermomechanical treatment (LTMT) on the strength, hardness, resistance to cold abrasion, fatigue strength, and cutting properties of high-speed steels was found in [4-7]. However, this method is not used in industry due to the low ductility of high-speed steels in the LTMT temperature range (400-600░C). High-temperature thermomechanical treatment (HTMT) is not used for high-speed steels
The influence of Cr content on the mechanical properties of ODS ferritic steels
NASA Astrophysics Data System (ADS)
Li, Shaofu; Zhou, Zhangjian; Jang, Jinsung; Wang, Man; Hu, Helong; Sun, Hongying; Zou, Lei; Zhang, Guangming; Zhang, Liwei
The present investigation aimed at researching the mechanical properties of the oxide dispersion strengthened (ODS) ferritic steels with different Cr content, which were fabricated through a consolidation of mechanical alloyed (MA) powders of 0.35 wt.% nano Y2O3 dispersed Fe-12.0Cr-0.5Ti-1.0W (alloy A), Fe-16.0Cr-0.5Ti-1.0W (alloy B), and Fe-18.0Cr-0.5Ti-1.0W (alloy C) alloys (all in wt.%) by hot isostatic pressing (HIP) with 100 MPa pressure at 1150 ░C for 3 h. The mechanical properties, including the tensile strength, hardness, and impact fracture toughness were tested by universal testers, while Young's modulus was determined by ultrasonic wave non-destructive tester. It was found that the relationship between Cr content and the strength of ODS ferritic steels was not a proportional relationship. However, too high a Cr content will cause the precipitation of Cr-enriched segregation phase, which is detrimental to the ductility of ODS ferritic steels.
Investigations of the formability of BCC steel sheets by using crystalline plasticity finite element analysis
C. L. Xie; E. Nakamachi
The effect of crystallographic texture on the formability of BCC steel sheets was studied by using crystalline plasticity finite element (FE) analysis. Three kinds of BCC steel sheets, mild steel, dual phase steel and high strength steel, were adopted as the examples in this investigation. At first, the crystal orientations of the three steel sheets were obtained by X-ray diffraction
Fatigue Properties of Heat-Treated 30MSV6 Vanadium Microalloyed Steel
NASA Astrophysics Data System (ADS)
Hajisafari, M.; Nategh, S.; Yoozbashizadeh, H.; Ekrami, A.
In the present study, 30MSV6 microalloyed steel was heat treated under different conditions, and the relation between its microstructure and mechanical properties was investigated. Scanning electron microscopy and transmission electron microscopy were used to characterize the microstructure of the heat-treated steel, and the effect of microstructure on tensile strength and fatigue behavior was determined. Microstructural analysis indicated that precipitates were formed at different sites such as grain boundaries and sub-grain boundaries. Furthermore, microstructural studies accompanied by the evaluation of mechanical properties revealed that the optimal heat treatment cycle of 30MSV6 microalloyed steel involved austenitization at 1223 K for 1 h and cooling in air to room temperature, followed by aging at 873 K for 1.5 h. The optimal heat treatment cycle resulted in significant improvement in the fatigue strength, tensile strength, and ductility because of the development of a uniform distribution of fine precipitates in a refined microstructure. The fatigue limit under optimum conditions (~384 MPa) was greater than that under other conditions (~321 and 312 MPa).
Almen intensity effect on microstructure and mechanical properties of low carbon steel subjected to severe shot peening
NASA Astrophysics Data System (ADS)
Unal, Okan; Varol, Remzi
This paper discusses alteration of microstructure and mechanical properties of low carbon steel after severe shot peening process. An ultra fine grained surface layer was formed on AISI 1017 mild steel by means of severe shot peening process. Surface characteristics were affirmed using optical microscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Nano hardness measurements were taken along the depth from shot peened surface using nanoindentation methods. The results showed that severe (unconventional) air blast shot peening process is an effective way to obtain ultra fine grained surface layer and to obtain superior mechanical properties.
Characterization of microstructure, mechanical properties and corrosion resistance of dissimilar welded joint between 2205 duplex stainless steel and 16MnR
Shaogang Wang; Qihui Ma; Yan Li
The joint of dissimilar metals between 2205 duplex stainless steel and 16MnR low alloy high strength steel are welded by tungsten inert gas arc welding (GTAW) and shielded metal arc welding (SMAW) respectively. The microstructures of welded joints are investigated using scanning electron microscope, optical microscope and transmission electron microscopy respectively. The relationship between mechanical properties, corrosion resistance and microstructure
Mechanical properties microstructure correlation in neutron irradiated heat-affected zones of austenitic stainless steels
NASA Astrophysics Data System (ADS)
Stoenescu, R.; Schaeublin, R.; Gavillet, D.; Baluc, N.
The effects of neutron irradiation on austenitic stainless steels, usually used for the manufacturing of internal elements of nuclear reactors (e.g. the core shrouds), are the alteration of the microstructure, and, as a consequence, of the mechanical properties. The present study is aimed at extending knowledge upon the impact of neutron-irradiation on the heat-affected zone of welded materials, which was influenced by the thermal cycles upon fusion welding. An austenitic stainless steel weld type AISI 304 from a decommissioned experimental pressurised water reactor has been used in the present study. The welded material has been irradiated during 11 reactor cycles to a maximum dpa dose of 0.35 and a temperature of around 573 K. The mechanical properties and microstructure are determined on specimens from heat-affected zone and base materials, with different dose levels. The mechanical properties were determined by performing tensile tests on small flat specimens at two deformation temperatures: room temperature and about 573 K. The characterisation of the microstructure was made by transmission electron microscopy. The correlation between mechanical properties and microstructure after neutron irradiation is made using the dispersed obstacle hardening model. It was found that the measured radiation hardening cannot be explained solely by the presence of the irradiation-induced defects observed in TEM. Smaller irradiation-induced features not resolvable in TEM may also contribute to radiation hardening.
Experimental study of the mechanical properties of light gauge cold-formed steels at elevated temperatures
Thanuja Ranawaka; Mahen Mahendran
In recent times, light gauge cold-formed steel sections have been used extensively as primary load-bearing structural members in many applications in the building industry. Fire safety design of structures using such sections has, therefore, become more important. Deterioration of mechanical properties of yield stress and elasticity modulus is considered the most important factor affecting the performance of steel structures in
High strength Fe¢Mn¢(Al, Si) TRIP\\/TWIP steels development Ś properties Ś application
O Grõssel; L Kr³ger; G Frommeyer; L. W Meyer
Deformation twinning, martensitic phase transformation and mechanical properties of austenitic Fe-(15¢30) wt.%Mn steels with additions of aluminium and silicon have been investigated. It is known that additions of aluminium increase the stacking fault energy ?fcc and therefore strongly suppress the ??? transformation while silicon decrease ?fcc and sustains the ??? transformation. The ??? phase transformation takes place in steels with
Correlations between microstructure and mechanical properties during PWHT of TMCP steel weld HAZ
M. Nakamura; H. Horie; K. Tagashira; H. Kawashima
This paper describes an investigation of the correlation between HAZ microstructures amd mechanical properties in the post?weld heat treatment (PWHT) of two types of thermomechanical control process steels (TMCP steels), especially the relationship between the stress relaxation behaviour and high?temperature deformability. Simulated weld heat treatment was performed with a welding thermal cycle simulator at a maximum temperature of 1623 K.
Advantages, properties and types of coatings on non-oriented electrical steels
M. Lindenmo; A Coombs; D Snell
Electrical steels used for motor, transformer and generator applications are usually coated with an insulation coating in order to improve the performance of the material in terms of reduced power loss, punching and welding characteristics and corrosion resistance. The advantages, properties and types of insulation coatings available at European Electrical Steels are discussed in this paper.
Morgan, M.; Tosten, M.; Chapman, G.
The deformation and fracture toughness properties of forged stainless steels pre-charged with tritium were compared to the deformation and fracture toughness properties of the same steels heat treated at 773 K or 873 K and precharged with hydrogen. Forged stainless steels pre-charged with tritium exhibit an aging effect: Fracture toughness values decrease with aging time after precharging because of the increase in concentration of helium from tritium decay. This study shows that forged stainless steels given a prior heat treatment and then pre-charged with hydrogen also exhibit an aging effect: Fracture toughness values decrease with increasing time at temperature. A microstructural analysis showed that the fracture toughness reduction in the heat-treated steels was due to patches of recrystallized grains that form within the forged matrix during the heat treatment. The combination of hydrogen and the patches of recrystallized grains resulted in more deformation twinning. Heavy deformation twinning on multiple slip planes was typical for the hydrogen-charged samples; whereas, in the non-charged samples, less twinning was observed and was generally limited to one slip plane. Similar effects occur in tritium pre-charged steels, but the deformation twinning is brought on by the hardening associated with decay helium bubbles in the microstructure.
Mechanical properties of cobalt-chromium wires compared to stainless steel and ?-titanium wires
Alobeid, Ahmad; Hasan, Malak; Al-Suleiman, Mahmoud; El-Bialy, Tarek
Background: Previous studies have reported on mechanical properties of different orthodontic wires. However, there is a paucity of information that comparing the mechanical properties of Blue Elgiloy (BE) when compared to stainless steel and TMA, as finishing wires as received by different companies. Aims: The aim of this study was to evaluate the mechanical properties of BE wires compared to stainless steel (SS) and titanium Molybdenum alloy (TMA) also known as ? titanium as provided by two companies. Materials and Methods: Six 0.016 x 0.022-14mm-samples of each wire were fixed individually to Instron machine and were tested in loading and unloading for three times. The initial load was set for 500 Kg at a speed of 1mm/min and displacement was adjusted for (0.5, 1mm in loading and 0.5 mm unloading at 25░C). Statistics Analysis: Variables were compared between groups by ANOVA test using SPSS statistical software. Results: BE shows comparable forces to SS when loaded 0.5 and showed decreased forces in 1mm loading compared to SS, and higher than TMA. BE also showed no forces at unloading and high deformation. Conclusion: BE from the two companies showed comparable mechanical properties while SS and TMA were different. The deformation of BE and its decreased forces in unloading may limit its clinical use. PMID:25426458
Surface electrical properties of stainless steel fibres: An AFM-based study
NASA Astrophysics Data System (ADS)
Yin, Jun; D'Haese, Cķcile; Nysten, Bernard
Atomic force microscopy (AFM) electrical modes were used to study the surface electrical properties of stainless steel fibres. The surface electrical conductivity was studied by current sensing AFM and I-V spectroscopy. Kelvin probe force microscopy was used to measure the surface contact potential. The oxide film, known as passivation layer, covering the fibre surface gives rise to the observation of an apparently semiconducting behaviour. The passivation layer generally exhibits a p-type semiconducting behaviour, which is attributed to the predominant formation of chromium oxide on the surface of the stainless steel fibres. At the nanoscale, different behaviours are observed from points to points, which may be attributed to local variations of the chemical composition and/or thickness of the passivation layer. I-V curves are well fitted with an electron tunnelling model, indicating that electron tunnelling may be the predominant mechanism for electron transport.
Effect of microstructure and texture on formability and mechanical properties of hot-dip galvanized steel sheets
M. Safaeirad; M. R. Toroghinejad; F. Ashrafizadeh
Lead content of zinc bath has significant effects on microstructure, texture and as a result on formability and mechanical properties of zinc-coated steel. In this study, microstructures of samples made from hot-dip galvanized sheets were examined by optical and scanning electron microscopy and their chemical compositions were analyzed by energy dispersive spectroscopy (EDS). The crystallographic orientation of the coatings was
Relationship between Material Properties and Local Formability of DP980 Steels
Choi, Kyoo Sil; Soulami, Ayoub; Li, Dongsheng; Sun, Xin; Khaleel, Mohammad A.; Xu, Le; Barlat, Frederic
A noticeable degree of inconsistent forming behaviors has been observed for the 1st generation advanced high strength steels (AHSS) in production, and they appear to be associated with the inherent microstructural-level inhomogeneities for various AHSS. This indicates that the basic material property requirements and screening methods currently used for the mild steels and high strength low alloys (HSLA) are no longer sufficient for qualifying todayÆs AHSS. In order to establish more relevant material acceptance criteria for AHSS, the fundamental understandings on key mechanical properties and microstructural features influencing the local formability of AHSS need to be developed. For this purpose, in this study, DP980 was selected as model steels and eight different types of DP980 sheet steels were acquired from various steel suppliers. Various experiments were then performed on the eight different DP980 steels such as chemical composition analysis, static tensile test, hole expansion test, channel forming test. Scanning electron microscope (SEM) pictures of the DP980 steels were also obtained, and image processing tools were then adopted to those SEM pictures in order to quantify their various microstructural features. The results show that all DP980 steels show large discrepancy in their performance and that the tensile properties and hole expansion properties of these steels do not correlate with their local formability. According to the results up to date, it is not possible to correlate the microstructural features alone to the macroscopically measured deformation behaviors. In addition to image analysis, other experiments (i.e., nano-indentation test) are also planned to quantify the individual phase properties of the various DP steels.
Microstructural Characterization and Mechanical Performance of Hot Work Tool Steel Processed by Selective Laser Melting
NASA Astrophysics Data System (ADS)
Holzweissig, Martin Joachim; Taube, Alexander; Brenne, Florian; Schaper, Mirko; Niendorf, Thomas
Microstructural characterization of hot work tool steel processed by selective laser melting was carried out. The findings shed light on the interrelationship between processing parameters and the microstructural evolution. It was found that the microstructure after layer-wise processing partially consists of metastable-retained austenite which transforms to martensite in a subsequent tensile test. This improves the mechanical properties of the hot work tool steel enabling direct application.
Microstructures and mechanical properties of Fe-14Cr-3W-Ti-Y 2O 3 steel with 1 wt.% Cu addition fabricated by a new method
NASA Astrophysics Data System (ADS)
Liu, Feng; Liu, Yong; Wen, Yuren; Dou, Yuhai; Zhao, Dapeng; Liu, C. T.
Effect of 1 wt.% copper addition on microstructures and mechanical properties of Fe-14Cr-3W-0.4Ti-0.4Y 2O 3 (wt.%) alloy has been investigated. Mechanically alloyed powders and pre-alloyed powders were blended and consolidated by hot extrusion. A bimodal grain structure with large grains (10-20 ?m) and nanometer grains was formed. Through aging treatment, ?-Cu phase with face cubic centered lattice structure precipitated from the supersaturated solid solution. After aging for 6 h, the microhardness reached a peak value of HV326, which was attributed to precipitation of copper-rich phase. The alloy exhibited a high strength due to the strengthening of both copper-rich precipitates and Y-Ti-O nanoclusters, and an excellent ductility due to its bimodal structure.
Preparation and properties on the graphite\\/polypropylene composite bipolar plates with a 304 stainless steel by compression molding for PEM fuel cell
Yang-Bok Lee; Choong-Hyun Lee; Kyung-Min Kim; Dae-Soon Lim
Graphite\\/polymer composites have high corrosion resistance, low contact resistance and low fabrication cost but low cell efficiency and mechanical strength. This study examined the electrical and mechanical properties of graphite\\/polypropylene composite bipolar plates. Carbon nanotubes (CNTs) were used to improve the electrical properties of the graphite\\/PP composites. Although the electrical properties increased when excess conducting filler was added to the
Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel
NASA Astrophysics Data System (ADS)
Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Jang, Min-Ho; Park, Min-Gu; Han, Heung Nam
In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 ░C and tempering at 750 ░C, while the HAZs consisted of martensite, ?-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and ?-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the ?-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the ?-ferrite remained in the tempered HAZs.
Influence of Martensite Mechanical Properties on Failure Mode and Ductility of Dual Phase Steels
Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.
In this paper, the effects of the mechanical properties of the martensite phase on the failure mode and ductility of dual phase (DP) steels are investigated using a micromechanics-based finite element method. Actual microstructures of DP sheet steels obtained from scanning electron microscopy are used as representative volume element (RVE) in two-dimensional plane-stress finite element calculations. Failure is predicted as plastic strain localization in the RVE during deformation. The mechanical properties of the ferrite and martensite phases in a commercial DP 980 steel are obtained based on the in-situ X-ray diffraction measurements of a uniaxial tensile test. Computations are then conducted on the RVE in order to investigate the influence of the martensite mechanical properties and volume fraction on the macroscopic behavior and failure mode of DP steels. The computations show that, as the strength and volume fraction of the martensite phase increase, the ultimate tensile strength (UTS) of DP steels increases but the UTS strain and failure strain decrease. These results agree well with the general experimental observations on DP steels. Additionally, shear dominant failure modes usually develop for DP steels with lower martensite strengths, whereas split failure modes typically develop for DP steels with higher martensite strengths.
Structure and sliding wear behavior of 321 stainless steel\\/Al composite coating deposited by high velocity arc spraying technique
Yong-xiong CHEN; Bin-shi XU; Yan LIU; Xiu-bing LIANG; Yi XU
A typical 321 stainless steel\\/aluminum composite coating (321\\/Al coating) was prepared by high velocity arc spraying technique (HVAS) with 321 stainless steel wire as the anode and aluminum wire as the cathode. The traditional 321 stainless steel coating was also prepared for comparison. Tribological properties of the coatings were evaluated with the ring-block wear tester under different conditions. The structure
Effect of Microstructure on Mechanical Properties of High Strength Steel Weld Metals
Keehan, Enda
The effects of variations in alloying content on the microstructure and mechanical properties of high strength steel weld metals have been studied. Based on neural network modelling, weld metals were produced using shielded metal arc welding...
Creation of superhydrophobic stainless steel surfaces by acid treatments and hydrophobic film deposition.
Li, Lester; Breedveld, Victor; Hess, Dennis W
In this work, we present a method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance. Creation of surface roughness on 304 and 316 grade stainless steels was performed using a hydrofluoric acid bath. New insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the stainless steel surfaces. As a result of intergranular corrosion, along with metallic oxide and fluoride redeposition, surface roughness was generated on the nano- and microscales. Differences in alloy composition between 304 and 316 grades of stainless steel led to variations in etch rate and different levels of surface roughness for similar etch times. After fluorocarbon film deposition to lower the surface energy, etched samples of 304 and 316 stainless steel displayed maximum static water contact angles of 159.9 and 146.6░, respectively. However, etching in HF also caused both grades of stainless steel to be susceptible to corrosion. By passivating the HF-etched samples in a nitric acid bath, the corrosion resistant properties of stainless steels were recovered. When a three step process was used, consisting of etching, passivation and fluorocarbon deposition, 304 and 316 stainless steel samples exhibited maximum contact angles of 157.3 and 134.9░, respectively, while maintaining corrosion resistance. PMID:22913317
Effect of deformation temperature on mechanical properties of austenitic steels
A. N. Chukhleb; V. P. Martynov
In several steels a complex relationship has been noted between the ; degree of deforraation and the ability of the alloy to undergo martensitic ; transformation upon cooling it was found that a slight amount of preliminary ; deformation of austenitic stainless steels enhances the martensitic ; transformation while a strong deformation results in the partial stabilization of ; the
Modeling of Failure Modes Induced by Plastic Strain Localization in Dual Phase Steels
Sun, Xin; Liu, Wenning N.; Choi, Kyoo Sil; Khaleel, Mohammad A.; Ren, Yang; Jia, N.; Wang, Y. D.
Microstructure level inhomogeneity between the harder martensite phase and the softer ferrite phase renders the dual phase (DP) steels more complicated failure mechanisms and associated failure modes compared to the conventionally used low alloy homogenous steels. This paper examines the failure mode DP780 steel and DP 980 steel under different loading conditions using finite element analyses on the microstructure levels. Micro-mechanics analyses based on the actual microstructures of DP steel are performed. The two-dimensional microstructure of DP steel was recorded by scanning electron microscopy (SEM). Mechanical properties of the ferrite and martensite phases exhibit the dependency of the different chemistry and thermal mechanical processes. The plastic work hardening properties of the ferrite phase was determined by the synchrotron-based high-energy X-ray diffraction technique. The work hardening properties of the martensite phase were calibrated and determined based on the uniaxial tensile test results. Under different loading conditions, different failure modes are predicted in the form of plastic strain localization. The local failure mode was closely related to the stress state in the material. Under plane stress condition with free lateral boundary, one dominant shear band develops and leads to final failure of the material. However, if the lateral boundary was strictly constrained, splitting failure perpendicular to the loading direction is predicted. On the other hand, under plane strain loading condition, commonly observed necking phenomenon is predicted which leads to the final failure of the material. Numerical predictions were well validated by the experimental.
The comparison of surface characteristics, physico-chemical and biological properties of 304 stainless steel coated by melt-derived and sol¢gel-derived 45S5 bioglass for orthopedic applications
Ali Pedram; S. Morteza Naghib; Amin Feizpour; Mojtaba Ansari
The ability of 45S5 bioglass to form a bond to living bone tissue and stimulate bone-cell proliferation may be different for melt- and sol¢gel-derived samples. In this research, the differences in corrosion resistance, bioactivity and physical properties between the melt- and sol¢gel-derived 45S5 bioglass coated on the surface of austenitic 304 stainless steel (SS) as a dental and orthopedic metallic
Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components
R. L. Sindelar; G. R. Jr. Caskey
The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950`s are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials
Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components
R. L. Sindelar; G. R. Jr. Caskey
The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials
M Morgan; M Monica Hall; P Ps Lam; D Dean Thompson
The effect of hydrogen on the burst properties Type 304L stainless steel vessels was investigated. The purpose of the study was to compare the burst properties of hydrogen-exposed stainless steel vessels burst with different media: water, helium gas, or deuterium gas. A second purpose of the tests was to provide data for the development of a predictive finite-element model. The
Helium effects on creep properties of Fe-14CrWTi ODS steel at 650 ░C
NASA Astrophysics Data System (ADS)
Chen, J.; Jung, P.; Rebac, T.; Duval, F.; Sauvage, T.; de Carlan, Y.; Barthe, M. F.
In the present paper, the effects of helium on creep properties of Fe-14CrWTi ODS steel were studied by in-beam and post He-implantation creep tests. In-situ creep was performed in an in-beam creep device under uniaxial tensile stresses from 350 to 370 MPa during homogeneous helium implantation. Helium ions of energies varying from 0 to 25 MeV were implanted at a rate of 6 ū 10-3 appm/s (corresponding to a displacement dose rate of 1.5 ū 10-6 dpa/s). The average temperature was controlled to 650 ░C within ▒2 ░C. In addition, post He-implantation creep tests were conducted at 650 ░C as well. Subsequently, fracture surfaces and helium bubble evolution were studied in detail by SEM and TEM observations, respectively. Preliminary creep results show that helium slightly shortens the creep life time of ODS steel at 650 ░C. Fracture surfaces of reference as well as implanted specimens, show areas with various grades of deformation. Areas of highest deformation can be interpreted as necking, while areas of low deformation show in helium implanted specimens a more granular structure. The results are discussed in terms of possible embrittlement of ODS steels by helium.
Measurement of the magnetic properties of P9 and T22 steel taken from service in power station
NASA Astrophysics Data System (ADS)
Wilson, J. W.; Karimian, N.; Liu, J.; Yin, W.; Davis, C. L.; Peyton, A. J.
With the UK's aging power generation network, life-extension of steel plant components is a critical issue. However, in order to evaluate the likelihood of component failure, techniques must be developed to properly assess the level of degradation in power station steels. Electromagnetic inspection has the potential to quantify the level of degradation through in-situ measurements at elevated temperatures. This paper reports the results of tests carried out on thermally treated P9 and T22 steel samples with different microstructural states using major and minor B-H loop measurements and magnetic Barkhausen noise measurements. The results show that by careful selection of minor loop parameters, specific to the material under inspection and the material change under consideration, correlations can established between EM properties and material properties such as Vickers hardness. These results will be used as a basis for the further development of a fully field deployable device.
Oxide barrier coatings on steel strip by spray pyrolysis
R. L¾pez Ibß±ez; J. R. Ramos Barrado; F. MartĒn; F. Brucker; D. Leinen
ZnO, TiO2 and ZrO2 thin films have been deposited by chemical spray pyrolysis onto differently galvanized steel strips (ThyssenKrupp Steel) for its potential use as protective layer against degradation due to ambient impact during long-term outdoor exposure. The steel strips shall be used as base material for unglazed solar collectors (EU project: SOLABS)11http:\\/\\/www.solabs.net\\/. and must thus comply including all its
Creep-fatigue interaction and related structure property correlations of EUROFER97 steel at 550 ░C by decoupling creep and fatigue load
NASA Astrophysics Data System (ADS)
Vorpahl, C.; M÷slang, A.; Rieth, M.
Mechanical tests have been performed at 550 ░C under vacuum on the ferritic-martensitic steel EUROFER97. These experiments included fatigue tests, creep tests and combined creep-fatigue tests. The latter showed significant cyclic softening in the fatigue stage and a remarkable break-down of creep strength in the creep stage. The cyclic softening behaviour was almost identical for all tests and therefore insensitive to the different strain amplitudes. SEM of the specimen's fracture surfaces and free surfaces revealed that networks of coagulated surface cracks formed during creep-fatigue were not failure relevant. TEM imaging displayed a drastic drop in dislocation density, and a considerable formation of precipitates and subgrain-structures in all tests. Pure fatigue led to the strongest reduction of dislocation density, whereas creep-fatigue induced the most pronounced formation of precipitates. Obviously, the internal softening due to prior cycling led to accelerated creep. Hence, a modified damage model for creep-fatigue load cases was proposed.
Fracture properties of a neutron-irradiated stainless steel submerged arc weld cladding overlay
Corwin, W.R.; Berggren, R.G.; Nanstad, R.K.
The ability of stainless steel cladding to increase the resistance of an operating nuclear reactor pressure vessel to extension of surface flaws depends greatly on the properties of the irradiated cladding. Therefore, weld overlay cladding irradiated at temperatures and fluences relevant to power reactor operation was examined. The cladding was applied to a pressure vessel steel plate by the submerged arc, single-wire, oscillating-electrode method. Three layers of cladding provided a thickness adequate for fabrication of test specimens. The first layer was type 309, and the upper two layers were type 308 stainless steel. The type 309 was diluted considerably by excessive melting of the base plate. Specimens were taken from near the base plate-cladding interface and also from the upper layers. Charpy V-notch and tensile specimens were irradiated at 288/sup 0/C to a fluence of 2 x 10/sup 23/ neutrons/m/sup 2/ (>1 MeV). 10 refs., 16 figs., 4 tabs.
Microstructure and Mechanical Properties of 316L Stainless Steel Filling Friction Stir-Welded Joints
NASA Astrophysics Data System (ADS)
Zhou, L.; Nakata, K.; Tsumura, T.; Fujii, H.; Ikeuchi, K.; Michishita, Y.; Fujiya, Y.; Morimoto, M.
Keyhole left at 316L stainless steel friction stir welding/friction stir processing seam was repaired by filling friction stir welding (FFSW). Both metallurgical and mechanical bonding characteristics were obtained by the combined plastic deformation and flow between the consumable filling tool and the wall of the keyhole. Two ways based on the original conical and modified spherical keyholes, together with corresponding filling tools and process parameters were investigated. Microstructure and mechanical properties of 316L stainless steel FFSW joints were evaluated. The results showed that void defects existed at the bottom of the refilled original conical keyhole, while excellent bonding interface was obtained on the refilled modified spherical keyhole. The FFSW joint with defect-free interface obtained on the modified spherical keyhole fractured at the base metal side during the tensile test due to microstructural refinement and hardness increase in the refilled keyhole. Moreover, no ? phase but few Cr carbides were formed in the refilled zone, which would not result in obvious corrosion resistance degradation of 316L stainless steel.
By: Leif Karlsson, ESAB AB, Gothenburg. The large and steadily growing family of stainless steels can offer unique combina-
Cambridge, University of
temperature toughness, creep strength and formability. Although small in tonnage compared to mild steelsBy: Leif Karlsson, ESAB AB, Gothenburg. The large and steadily growing family of stainless steels can offer unique combina- tions of corrosion resistance and properties such as high strength, low
Characterization of microstructures and mechanical properties of Inconel 617/310 stainless steel dissimilar welds
Shah Hosseini, H., E-mail: email@example.com; Shamanian, M.; Kermanpur, A.
The microstructure and mechanical properties of Inconel 617/310 austenitic stainless steel dissimilar welds were investigated in this work. Three types of filler materials, Inconel 617, Inconel 82 and 310 austenitic stainless steels were used to obtain dissimilar joint using the gas tungsten arc welding process. Microstructural observations showed that there was no evidence of any possible cracking in the weldments achieved by the nickel-base filler materials. The welds produced by 617 and 310 filler materials displayed the highest and the lowest ultimate tensile strength and total elongation, respectively. The impact test results indicated that all specimens exhibited ductile fracture. Among the fillers, Inconel 617 exhibited superlative fracture toughness (205 J). The mechanical properties of the Inconel 617 filler material were much better than those of other fillers. - Research Highlights: {yields} A fine dendritic structure was seen for the Inconel 617 weld metal. {yields} A number of cracks were initiated when the 310 SS filler metal was used. {yields} All welded samples showed ductile fracture. {yields} The Inconel 617 filler material presents the optimum mechanical properties.
Lam, P; Andrew Duncan, A; Robert Sindelar, R; Thad Adams, T
Literature survey has been performed for a compendium of mechanical properties of carbon and low alloy steels following hydrogen exposure. The property sets include yield strength, ultimate tensile strength, uniform elongation, reduction of area, threshold stress intensity factor, fracture toughness, and fatigue crack growth. These properties are drawn from literature sources under a variety of test methods and conditions. However, the collection of literature data is by no means complete, but the diversity of data and dependency of results in test method is sufficient to warrant a design and implementation of a thorough test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).
Lam, P; Robert Sindelar, R; Thad Adams, T
Literature survey has been performed for a compendium of mechanical properties of carbon and low alloy steels following hydrogen exposure. The property sets include yield strength, ultimate tensile strength, uniform elongation, reduction of area, threshold stress intensity factor, fracture toughness, and fatigue crack growth. These properties are drawn from literature sources under a variety of test methods and conditions. However, the collection of literature data is by no means complete, but the diversity of data and dependency of results in test method is sufficient to warrant a design and implementation of a thorough test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).
Analysis of the Dependence of Material Properties on Temperature - Steel 1.4122
NASA Astrophysics Data System (ADS)
Brnic, Josip; Turkalj, Goran; Vukelic, Goran; Brcic, Marino
This article presents an analysis of experimental data with reference to material properties, short-time creep and relaxation phenomena of 1.4122 steel (AISI 420RM) at high temperatures. The behaviour of the material subjected to uniaxial stress is indicated by engineering stress - strain diagrams. The data referring to tensile strength, 0.2 percent offset yield strength, the modulus of elasticity and total deformation, are shown through tables and curves presenting the dependence of these quantities on temperature. Creep and relaxation curves regarding certain level of stresses at selected temperatures are also shown. In addition, modelling of both creep and relaxation phenomena is presented.
Effect of alloying and heat treatment on the structure and tribological properties of nitrogen-bearing stainless austenitic steels under abrasive and adhesive wear
L. G. Korshunov; Yu. N. Goikhenberg; N. K. Chernenko
The effect of nitrogen, silicon, and aging modes on the structure, resistance to abrasive and adhesive wear, friction factor,\\u000a and mechanical properties of nitrogen-bearing (0.27¢0.83% N) chromium-manganese austenitic steels is studied. It is shown\\u000a that it is possible to ensure a favorable combination of mechanical and tribological properties in such steels by choosing\\u000a the appropriate chemical composition and aging mode.
Effect of Nitrogen on Stacking Fault Formation Probability and Mechanical Properties of Twinning-Induced Plasticity Steels
B. X. Huang; X. D. Wang; L. Wang; Y. H. Rong
Twinning induced plasticity (TWIP) steels containing nitrogen as the interstitial alloying element were designed, and the\\u000a effects of N and Al on stacking fault energy (SFE), microstructure, and mechanical properties were investigated by using X-ray\\u000a diffraction and transmission electron microscopy to determine the stacking fault formation probability. In addition, the microstructure\\u000a and mechanical properties have been characterized. The results indicate
Some mechanical and magnetic properties of cold rolled X5CrNi18-8 stainless steel
A. Kurc; Z. Stok
Purpose: The paper analyzes the influence of the degree of cold deformation on the structure forming and changes of mechanical and magnetic properties of cold-rolled sheet on austenitic X5CrNi18-8 stainless steel. Design\\/methodology\\/approach: The investigations included observations of the structure on a light microscope, researches of mechanical properties in a static tensile test, microhardness measurements made by Vickers's method and magnetic
Effect of Impurity Tin on the Creep Properties of a P91 Heat-Resistant Steel
NASA Astrophysics Data System (ADS)
Song, S.-H.; Xu, Y.-W.; Yang, H.-F.
The creep properties of P91 steel specimens undoped and doped with 0.058 wt pct tin, which was normalized from 1328 K (1055 ░C) and tempered at 1033 K (760 ░C), were examined under different engineering stresses (150 to 210 MPa) and temperatures [873 K to 923 K (600 ░C to 650 ░C)]. The creep behavior followed the temperature-compensated power law and Monkman-Grant equations. In the temperature-compensated power law equation, the apparent activation energy and stress exponent for creep were approximately 541 kJ/mol and 12 for the undoped steel and 527 kJ/mol and 11 for the Sn-doped one, respectively. In the Monkman-Grant relation, the values of constants m and C were around 1.062 and 0.0672 for the undoped steel, and 1.012 and 0.0650 for the Sn-doped one, respectively. The 100 MPa stress creep lifetime at 873 K (600 ░C) was estimated as 100641 hours for the undoped steel and 35290 hours for the Sn-doped steel, respectively. These indicated that Sn substantially deteriorated the creep properties of the steel. It was found that grain or subgrain boundary segregation of Sn could promote the nucleation of cavities or microcracks, thereby leading to the deterioration of the steel creep properties.
Functional properties of laser modified surface of tool steel
M. Bonek; L. A. Dobrza?ski
Purpose: Investigations include alloying the surface of X40CrMoV5-1 hot-work tool steel with tungsten carbide using a high power diode laser (HPDL). Design\\/methodology\\/approach: The structural mechanism of surface layer development was determined and the effect of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the
Properties of cold-rolled high-strength steel sheets
K. Toda; H. Gondoh; H. Takechi; H. Masui
For high-strength steel sheets, a new concept has become necessary,viz, the relation between strength and formability. When the relation between tensile strength and elongation is appraised for\\u000a ranking in terms of the strengthening mechanism, it is found that the substitutional solid-solution hardening type is excellent\\u000a and the precipitation hardening type is inferior. In batch annealing, the phosphorus-added aluminum-killed steel sheets
Wetting Properties of Liquid Lithium on Stainless Steel and Enhanced Stainless Steel Surfaces
NASA Astrophysics Data System (ADS)
Fiflis, P.; Xu, W.; Raman, P.; Andruczyk, D.; Ruzic, D. N.; Curreli, D.
Research into lithium as a first wall material has proven its ability to effectively getter impurities and reduce recycling of hydrogen ions at the wall. Current schemes for introducing lithium into a fusion device consist of lithium evaporators, however, as these devices evolve from pulsed to steady state, new methods will need to be employed such as the LIMIT concept of UIUC, or thin flowing film lithium walls. Critical to their implementation is understanding the interactions of liquid lithium with various surfaces. One such interaction is the wetting of materials by lithium, which may be characterized by the contact angle between the lithium and the surface. Experiments have been performed at UIUC into the contact angle of liquid lithium with a given surface, as well as methods to increase it. To reduce the oxidation rate of the droplets, the experiments were performed in vacuum, using a lithium injector to deposit drops on each surface. Among the materials investigated are stainless steel, both untreated and coated with a diamond like carbon (DLC) layer, molybdenum, and boronized molybdenum. The contact angle and its dependence on temperature is measured.
Effects of Nb on the Microstructure and Mechanical Properties of Water-Quenched FGBA/BG Steels
NASA Astrophysics Data System (ADS)
Gao, Guhui; Feng, Chun; Bai, Bingzhe
In order to reduce the alloying cost, Mn-series low carbon water-quenched grain boundary allotriomorphic ferrite (FGBA)/granular bainite (BG) steels have been developed. The effect of 0.06 wt.% Nb on microstructure and mechanical properties of FGBA/BG steel was investigated. The result showed that the addition of 0.06 wt.% Nb improved the hardenability of the FGBA/BG steel, refined the grain size of FGBA, promoted the granular bainitic transformation, and refined the granular bainite including its bainitic ferrite and martensite/austenite (M/A) constituents. With the addition of 0.06 wt.% Nb, the yield strength increased from 560 to 741 MPa, and the impact energy increased from 93 to 151 J, respectively, for 30-mm thickness steel plates. It is supposed that the addition of 0.06 wt.% Nb could improve the mechanical properties of the FGBA/BG steel by refining the microstructure and increasing the amount of strengthening phases.
Phosphorus Removal in Sewage by Mixed Steel Slag Fillings
Huang Ling; Su Yongqiang
The purpose of the paper is purifying phosphorus by column experiment and researching phosphorus removal theory of substrates including steel slag, natural sand and limestone. The winch is composed of the following main parts: experiment method and procedure, results and discussion and conclusion. The results indicated: Pure steel slag is not suitable as filling in wastewater land treating. Mixing natural
Enhancement of the steel quenching process by an electric field
K. J. Cheng; G. W. Pearsall; J. B. Chaddock
An electric field is known to be able to increase considerably the heat flux during the boiling process by suppressing the occurrence of film boiling. This field enhancement technique can be applied to the steel quenching process to accelerate the cooling rate and thus increase the effective hardenability of the steel. This report describes a quench experiment performed with an
Early Detection of Steel Rebar Corrosion by Acoustic Emission Monitoring Early Detection of Steel Rebar Corrosion by Acoustic Emission
Early Detection of Steel Rebar Corrosion by Acoustic Emission Monitoring Early Detection of Steel Rebar Corrosion by Acoustic Emission Monitoring Alan D. Zdunek and David Prine BIRL Industrial Research, Evanston, IL 60201 Paper No. 547 presented at CORROSION95, the NACE International Annual Conference
Characterization of the magnetic micro- and nanostructure in unalloyed steels by magnetic force microscopy
NASA Astrophysics Data System (ADS)
Batista, L.; Rabe, U.; Hirsekorn, S.
The formation of a cementite phase influences significantly the macroscopic mechanical and magnetic properties of steels. Based on a correlation between mechanical and magnetic properties, mechanical properties as well as the morphology and content of the cementite phase can be inspected by electromagnetic non-destructive testing methods. The influence of the carbon content on bulk magnetic properties of unalloyed steels is studied on a macroscopic scale by hysteresis loop and Barkhausen noise measurements. The micro- and nanostructure is investigated by atomic force microscopy and magnetic force microscopy. Surface topography images and magnetic images of globular cementite precipitates embedded in a ferrite matrix are presented. The size, shape, and orientation of the precipitates influence the domain configuration. Applied external magnetic fields cause magnetization processes mainly in the ferrite matrix: Bloch walls move and are pinned by the cementite precipitates. The correlation between the microscopic observations and macroscopic magnetic properties of the material is discussed.
Effects of Strain Rates on Mechanical Properties and Fracture Mechanism of DP780 Dual Phase Steel
NASA Astrophysics Data System (ADS)
Li, Shengci; Kang, Yonglin; Zhu, Guoming; Kuang, Shuang
The mechanical properties of DP780 dual phase steel were measured by quasi-static and high-speed tensile tests at strain rates between 0.001 and 1000 s-1 at room temperature. The deformation and fracture mechanisms were analyzed by observation of the tensile fracture and microstructure near the fracture. Dynamic factor and feret ratio quantitative methods were applied to study the effect of strain rate on the microstructure and properties of DP780 steel. The constitutive relation was described by a modified Johnson-Cook and Zerilli-Armstrong model. The results showed that the strain rate sensitivity of yield strength is bigger than that of ultimate tensile strength; as strain rate increased, the formation of microcracks and voids at the ferrite/martensite interface can be alleviated; the strain rate effect is unevenly distributed in the plastic deformation region. Moreover, both models can effectively describe the experimental results, while the modified Zerilli-Armstrong model is more accurate because the strain-hardening rate of this model is independent of strain rate.
Effects of Strain Rates on Mechanical Properties and Fracture Mechanism of DP780 Dual Phase Steel
NASA Astrophysics Data System (ADS)
Li, Shengci; Kang, Yonglin; Zhu, Guoming; Kuang, Shuang
The mechanical properties of DP780 dual phase steel were measured by quasi-static and high-speed tensile tests at strain rates between 0.001 and 1000 s-1 at room temperature. The deformation and fracture mechanisms were analyzed by observation of the tensile fracture and microstructure near the fracture. Dynamic factor and feret ratio quantitative methods were applied to study the effect of strain rate on the microstructure and properties of DP780 steel. The constitutive relation was described by a modified Johnson-Cook and Zerilli-Armstrong model. The results showed that the strain rate sensitivity of yield strength is bigger than that of ultimate tensile strength; as strain rate increased, the formation of microcracks and voids at the ferrite/martensite interface can be alleviated; the strain rate effect is unevenly distributed in the plastic deformation region. Moreover, both models can effectively describe the experimental results, while the modified Zerilli-Armstrong model is more accurate because the strain-hardening rate of this model is independent of strain rate.
Fatigue properties of transformation-induced plasticity and dual-phase steels for auto-body lightweight: Experiment, modeling and application
Z. G. Hu; P. Zhu; J. Meng
The substitution of conventional high strength steels (HSS) with advanced high strength steels (AHSS), e.g., low-alloy multiphase transformation-induced plasticity steel (TRIP steel) or dual-phase steel (DP steel), for body lightweight brings about increased stress of notched components. Thus the fatigue properties of TRIP and DP steels and the fatigue life of notched lightweight design are important considerations for reasonable material
Effects of plastic deformations on microstructure and mechanical properties of ODS-310 austenitic steel
NASA Astrophysics Data System (ADS)
Wang, Man; Zhou, Zhangjian; Sun, Hongying; Hu, Helong; Li, Shaofu
ODS-310 austenitic steel (Fe-25Cr-20Ni-0.35Y2O3-0.5Ti) was fabricated by the process of mechanical alloying and hot isostatic pressing. Plastic deformations, including forging and hot rolling, were applied to the as-hipped samples to improve the ductility. Microstructural evolutions in samples under different fabrication conditions were characterized by TEM. Tensile properties were tested at 23 ░C and 700 ░C. Dispersed oxide particles with sizes between 10 nm and 50 nm were characterized to be rich in Y-Ti-O. UTS and elongation of the as-hipped sample were 904 MPa and 11% respectively at 23 ░C. Elongation increased two times after plastic deformations while there was only slight decrease in strength properties.
Fabrication and mechanical properties of a 14Cr-ODS steel
NASA Astrophysics Data System (ADS)
Hu, Helong; Zhou, Zhangjian; Liao, Lu; Wang, Man; Li, Shaofu
In this paper, the fabrication method and the mechanical properties of a 14Cr-ODS steel are investigated. The pre-alloyed steel powders and oxide powders were mechanical alloyed after milling for 30 h under a rotation of 300 rpm. Y-Ti-O phase was obtained after annealing the MA powders at 1100 ░C. The tensile strength of the HIPed 14Cr-ODS steels at room temperature was about 1120 MPa. Micro structure observation showed that there were amount of nano dispersion particles in the base alloy which resulted in the high hardness and tensile strength.
Mechanical properties of laser-pressure-welded joint between dissimilar galvannealed steel and pure aluminium
Koji Nishimoto; Tomoki Harano; Yoshihiro Okumoto; Ken Atagi; Hiroo Fujii; Seiji Katayama
Dissimilar metal joints of Zn-coated Galvannealed steel (GA steel) and commercially available pure aluminium (A1050) sheets were produced by changing the laser power and the roller pressure by the laser pressure welding method. By this method, the YAG laser beam was irradiated into a flare groove made by these dissimilar metal sheets. In addition, the laser beam was scanned at
Tensile properties of the NLF reduced activation ferritic/martensitic steels after irradiation in a fast reactor spectrum to a maximum dose of 67 dpa
NASA Astrophysics Data System (ADS)
Maloy, Stuart A.; James, M. R.; Romero, T. J.; Toloczko, M. B.; Kurtz, R. J.; Kimura, A.
The NLF series of steels are reduced activation ferritic-martensitic (RAFM) steels that are a part of the Japanese program to produce a suitable reduced activation ferritic-martensitic steel for the ITER project. Published reports on the NLF steels after about 35 dpa at 400 ░C by Kurishita et al., indicate that these steels have similar strength and better ductility than other RAFM steels such as the JLF steels and F82H irradiated at 400 ░C to similar doses. The tensile properties of NLF steels irradiated at ?400 ░C to doses as high as 67 dpa are presented here. Tensile tests were conducted at a strain rate of 5 ū 10-4 s-1 at 25, 400 ░C, and 500 ░C. Variations in irradiation temperature in the range of 390-430 ░C had a relatively small, but definite effect on the tensile properties for tests conducted at 25, 400, and 500 ░C. The strongest hardening is observed for specimens irradiated at 390 ░C, and very little hardening is observed for specimens irradiated at 430 ░C. Strain rate jump tests were performed on NLF-0 and NLF-1 at 400 ░C after irradiation to 52 dpa. The rate sensitivity, m, is quite low, 0.003-0.005 and does not appear to be affected by irradiation at 52 dpa for an irradiation temperature of 430 ░C.
Microstructural Features Controlling Mechanical Properties in Nb-Mo Microalloyed Steels. Part II: Impact Toughness
NASA Astrophysics Data System (ADS)
Isasti, Nerea; Jorge-Badiola, Denis; Taheri, Mitra L.; Uranga, Pello
The present paper is the final part of a two-part paper where the influence of coiling temperature on the final microstructure and mechanical properties of Nb-Mo microalloyed steels is described. More specifically, this second paper deals with the different mechanisms affecting impact toughness. A detailed microstructural characterization and the relations linking the microstructural parameters and the tensile properties have already been discussed in Part I. Using these results as a starting point, the present work takes a step forward and develops a methodology for consistently incorporating the effect of the microstructural heterogeneity into the existing relations that link the Charpy impact toughness to the microstructure. In conventional heat treatments or rolling schedules, the microstructure can be properly described by its mean attributes, and the ductile-brittle transition temperatures measured by Charpy tests can be properly predicted. However, when different microalloying elements are added and multiphase microstructures are formed, the influences of microstructural heterogeneity and secondary hard phases have to be included in a modified equation in order to accurately predict the DB transition temperature in Nb and Nb-Mo microalloyed steels.
Study of TRIP-Aided Bainitic Ferritic Steels Produced by Hot Press Forming
NASA Astrophysics Data System (ADS)
Chen, Shangping; Rana, Radhakanta; Lahaije, Chris
A study is reported to produce high strength ductile steels by controlled cooling following hot press forming, instead of quenching, as is practiced in the traditional press hardened steels. Heat treatments of several specially designed low carbon steels were carried out by interrupting the fast cooling from the austenization temperature at temperatures between T 0 and Ms and then cooling in controlled rates to room temperature. The effect of the interrupt temperature and the cooling rate afterward on the microstructures and tensile properties was studied. The microstructures were characterized using dilatometry, optical microscopy, X-ray diffraction, and TEM. A multi-phase microstructure including bainite, martensite, and retained austenite was obtained in the simulated hot press forming process. Volume fraction bainite was found to increase with an increase in interrupt temperature and a decrease in cooling rate. Structure-property correlations of the studied steels heat treated at different conditions were developed. Improved tensile properties were obtained by controlling the interrupt temperature and cooling rate which produced an optimum bainite content of 60 to 75 pct and retained austenite. Unfortunately, the bainite in the simulated samples was not completely carbide free even though the steels contained about 1.6 wt pct of Si.
Mechanical Property Development During UOE Forming of Large Diameter Pipeline Steels
A. G. Kostryzhev; M. Strangwood; C. L. Davis
Mechanical properties of large diameter welded steel pipes depend on the thermomechanically controlled rolled (TMCR) plate microstructure and UOE pipe-forming cold deformation sequence. Strength from plate to pipe may increase (work-hardening) or decrease (the Bauschinger effect). Bauschinger effect parameters depend on steel composition and plate processing history. The present study is examining two pipeline grades: X60 (Nb-alloyed) and X65 (Nb-
Factors influencing fretting fatigue properties of plasma-nitrided low alloy steel
C. X Li; Y Sun; T Bell
709M40 steel samples were plasma-nitrided under various processing conditions. Fretting fatigue tests were carried out with a W÷hler rotating bending fatigue machine, using S¢N curves to evaluate the fretting fatigue properties of the untreated and plasma-nitrided steel. The influences of such structural factors as compound layer, case depth, case hardness and compressive residual stress on the fretting fatigue behaviour of
Effect of microfissures on fatigue properties of austenitic stainless steel weld metals
Y. Cui; Carl D. Lundin
High-cycle tension¢tension fatigue testing with a 0.1 stress ratio at a frequency of 20 Hz (load control at ambient temperature) was conducted on 316L stainless steel weld metals with and without microfissures. The test results show that microfissures (hot cracking) significantly decrease the fatigue properties in austenitic stainless steel weld metals. The initiation of failure for microfissure-containing samples is linked
Fatigue properties of welded joints using steel with high resistance to fatigue crack growth
Kiyotaka Nakashima; Hiroshi Shimanuki; Tetsuro Nose; Tadashi Ishikawa
It has been generally recognized that the fatigue life of welded joints is little influenced by the strength of steels owing to the high-stress concentration and the tensile residual stress near the weld toe. In this paper, improvement of the fatigue life of welded joints using steel with high resistance to fatigue crack growth (ferrite\\/martensite (F\\/M) steel) is investigated. F\\/M
Stress corrosion cracking properties of 15-5PH steel
NASA Technical Reports Server (NTRS)
Rosa, Ferdinand
Unexpected occurrence of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15-5PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a highly acidified sodium chloride (NaCl) aqueous solution. The selected alloy for the study was a 15-5PH steel in the H900 condition. The slow strain rate technique was selected to test the metals specimens.
Stochastic Modeling of Soft Magnetic Properties of Electrical Steels: Application to Stators of Electrical Machines
Paris-Sud XI, Universitķ de
1 Stochastic Modeling of Soft Magnetic Properties of Electrical Steels: Application to Stators magnetic materials properties (magnetic behavior law, iron losses) during the manufacturing process an impact on the magnetic behavior law and iron losses of the considered material [30-33]. Therefore
Photothermal measurement of thermal properties of thermal spray coated carbon steel substrates
B. Farahbakhsh; J. A. Garcia; A. Mandelis
Laser infrared photothermal radiometry (PTR) offers a nondestructive and remote technique for surface and coating characterization. This study summarizes the application of this technique to determine the thermophysical properties (thermal diffusivity and conductivity) of various thermal spray coated carbon steel substrates. In order to infer the material properties from the measurement scheme, a one-dimensional photothermal model of a 3-layered system
Fatigue and crack growth properties of type 316 steel for fusion applications
B. Van Der Schaaf; M. I. De Vries
The fatigue and crack growth properties of Type 316 steel relevant for application in the first wall and blanket structures of NET (Next European Torus) have been reviewed. Most of the presently available post-irradiation fatigue and crack propagation experiments are carried out at temperatures over 750 K, whereas for NET the properties at temperatures in the range of 500 to
Properties of stainless steels for fusion conductor jackets and their manufacturing techniques
S. Forster; P. Komarek; A. Nyilas; A. Ulbricht
A superconducting cable for a fusion magnet has to be reinforced by a stainless steel jacket which envelops the cable. The jackets are fabricated by extruded and butt welded steel sections or by composing the jacket from drawn sections with longitudinal welds. Fatigue life and fatigue crack growth rates (FCGRs) were investigated at 10 K for embedded and surface cracks
Oxidation resistance in LBE and air and tensile properties of ODS ferritic steels containing Al/Zr elements
NASA Astrophysics Data System (ADS)
Gao, R.; Xia, L. L.; Zhang, T.; Wang, X. P.; Fang, Q. F.; Liu, C. S.
The effects of Al and Zr addition on improvement of oxidation resistance in lead-bismuth eutectic (LBE) and in air as well as the tensile properties were investigated for the oxide dispersion strengthened (ODS) steels. The 16Cr-4Al-0.8Zr-ODS steel samples were fabricated by a sol-gel method combining with spark plasma sintering technique. The tests in LBE at 600 ░C for 1000 h indicate the good oxidation resistance comparing with the specimens without Zr/Al elements. The samples also exhibit superior oxidation resistance in air due to formation of dense and continuous aluminum oxide film. Minor Zr addition prevents the Al element induced coarsening of the oxide particles in ODS steels and significantly improves the ultimate tensile stress and total elongation of the samples.
Recycling zinc by dezincing steel scrap
Dudek, F.J.; Daniels, E.J. [Argonne National Lab., IL (United States); Morgan, W.A. [Metal Recovery Industries, Inc., East Chicago, IN (United States)
In response to the worldwide increase in consumption of galvanized steel for automobiles in the last fifteen years, and the increased cost of environmental compliance associated with remelting larger quantities of galvanized steel scrap, a process is being developed to separate and recover the steel and zinc from galvanized ferrous scrap. The zinc is dissolved from the scrap in hot caustic using anodic assistance and is recovered electrolytically as dendritic powder. The designed ferrous scrap is rinsed and used directly. The process is effective for zinc, lead, and aluminum removal on loose and baled scrap and on all types of galvanized steel. The process has been pilot tested in Hamilton, Ontario for batch treatment of 900 tonnes of mostly baled scrap. A pilot plant in East Chicago, Indiana has designed in a continuous process mode 900 tonnes of loose stamping plant scrap; this scrap typically has residual zinc below 0.1% and sodium dragout below 0.001%. This paper reviews pilot plant performance and the economics of recycling galvanized steel and recovering zinc using a caustic process.
Effect of Partial Replacement of Si with Al on the Microstructures and Mechanical Properties of 1000 MPa TRIP Steels
NASA Astrophysics Data System (ADS)
Wang, Chao; Ding, Hua; Zhang, Jun; Di, Huafang
Two newly synthesized C-Mn-Si-Mo-Nb transformation-induced plasticity (TRIP) steels with and without Al addition were designed in order to achieve significant improvements in the mechanical properties. The effect of substitution of Si by Al on tensile properties and the microstructure of cold-rolled C-Mn-Si TRIP steel was investigated under different heat treatments. It was shown that a complex ultrafine microstructure composed of different phases was formed and two types of morphology for ferrite were detected (equiaxial and polygonal). The distribution of alloying elements was observed by using electron probe microanalysis. It was clear that C was concentrated in the retained austenite (RA) and small M/A (austenite/martensite) islands. The Al addition facilitated the formation of polygonal ferrite and increased the stability of the RA. The strain-hardening behavior was studied in detail. All the investigated specimens showed a very high strain-hardening exponent (instantaneous n) but their strain dependence was different. For the C-Mn-Si-Mo-Nb TRIP steel, the maximum n value was achieved when the strain was only about 0.04, while the n value of the Al substituted TRIP steel increased gradually until strains in the range of 0.07-0.10 were reached and the maximum value was achieved. As a result, the elongations of the steel with Al addition increased considerably without obvious deterioration of strength. It was the first time to find microtwinned martensite located between ferrite and bainitic ferrite after tensile deformation in the low alloy TRIP steel with Al.
Nickel-doped ferritic (martensitic) steels for fusion reactor irradiation studies: tempering behavior and unirradiated and irradiated tensile properties
R. L. Klueh; J. M. Vitek; M. L. Grossbeck
When an alloy containing nickel is irradiated in a mixed-spectrum reactor, helium is produced in the lattice by the transmutation of ŌüĄŌüĖNi by thermal neutrons. Nickel doping of two ferritic (martensitic) steels is being used to determine the effect of simultaneously produced helium and displacement damage (produced by the fast neutrons in the spectrum) on the mechanical properties of these
Effect of boron addition on injection molded 316L stainless steel: mechanical, corrosion properties and in vitro bioactivity.
Bayraktaroglu, Esra; Gulsoy, H Ozkan; Gulsoy, Nagihan; Er, Ozay; Kilic, Hasan
The research was investigated the effect of boron additions on sintering characteristics, mechanical, corrosion properties and biocompatibility of injection molded austenitic grade 316L stainless steel. Addition of boron is promoted to get high density of sintered 316L stainless steels. The amount of boron plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders have been used with the elemental NiB powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperature. The debinded samples were sintered at different temperature for 60 min. Mechanical property, microstructural characterization and electrochemical property of the sintered samples were performed using tensile testing, hardness, optical, scanning electron microscopy and electrochemical corrosion experiments. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. Results of study showed that sintered 316L and 316L with NiB addition samples exhibited high mechanical and corrosion properties in a physiological environment. Especially, 316L with NiB addition can be used in some bioapplications. PMID:23114463
Microstructure and antibacterial properties of microwave plasma nitrided layers on biomedical stainless steels
NASA Astrophysics Data System (ADS)
Lin, Li-Hsiang; Chen, Shih-Chung; Wu, Ching-Zong; Hung, Jing-Ming; Ou, Keng-Liang
Nitriding of AISI 303 austenitic stainless steel using microwave plasma system at various temperatures was conducted in the present study. The nitrided layers were characterized via scanning electron microscopy, glancing angle X-ray diffraction, transmission electron microscopy and Vickers microhardness tester. The antibacterial properties of this nitrided layer were evaluated. During nitriding treatment between 350 ░C and 550 ░C, the phase transformation sequence on the nitrided layers of the alloys was found to be ? ? (? + ? N) ? (? + ? + CrN). The analytical results revealed that the surface hardness of AISI 303 stainless steel could be enhanced with the formation of ? N phase in nitriding process. Antibacterial test also demonstrated the nitrided layer processed the excellent antibacterial properties. The enhanced surface hardness and antibacterial properties make the nitrided AISI 303 austenitic stainless steel to be one of the essential materials in the biomedical applications.
The Effect of Nitrided Layer on Antibacterial Properties for Biomedical Stainless Steel
NASA Astrophysics Data System (ADS)
Hung, C. F.; Wu, C. Z.; Lee, W. F.; Ou, K. L.; Liu, C. M.; Peng, P. W.
Plasma nitriding of AISI type 303 austenitic stainless steel using microwave system at various input powers was conducted in present study. The nitrided layers were characterized via scanning electron microscopy, transmission electron microscopy and Vickers microhardness tester. The anti-bacterial property of this nitrided layer was also evaluated. The analytical results revealed the hardness of AISI type 303 stainless steel could be enhanced with nitriding process. The microstructure of the nitrided layer comprised of nitrogen-expanded ? phase. Bacterial test demonstrated the nitrided layer processed the excellent an ti-bacterial properties. The enhanced hardness and anti-bacterial properties make the nitrided AISI type 303 austenitic stainless steel the potential material in the biomedical applications.
Increasing the efficiency of ladle desulfurization of steel by using regenerated slags
V. A. Bigeev; L. V. Petrov; K. N. Vdovin; V. N. Kotii; A. V. Deryabin
The volume of steel subjected to ladle desulfurization can be increased by regenerating spent synthetic slags and returning them to the production cycle. Two problems encountered in the restoration of the desulfurizing properties of the slags are the need to reduce the content of the oxides of silicon and iron and remove sulfur to the 0.03-0.06 level. Difficulties and solutions
Surface enhancement of cold work tool steels by friction stir processing with a pinless tool
NASA Astrophysics Data System (ADS)
Costa, M. I.; Verdera, D.; Vieira, M. T.; Rodrigues, D. M.
The microstructure and mechanical properties of enhanced tool steel (AISI D2) surfaces produced using a friction stir welding (FSW) related procedure, called friction stir processing (FSP), are analysed in this work. The surface of the tool steel samples was processed using a WC-Co pinless tool and varying processing conditions. Microstructural analysis revealed that meanwhile the original substrate structure consisted of a heterogeneous distribution of coarse carbides in a ferritic matrix, the transformed surfaces consisted of very small carbides, homogenously distributed in a ferrite- bainite- martensite matrix. The morphology of the surfaces, as well as its mechanical properties, evaluated by hardness and tensile testing, were found to vary with increasing tool rotation speed. Surface hardness was drastically increased, relative to the initial hardness of bulk steel. This was attributed to ferrite and carbide refinement, as well as to martensite formation during solid state processing. At the highest rotation rates, tool sliding during processing deeply compromised the characteristics of the processed surfaces.
Correlations between mechanical properties and cavitation erosion resistance for stainless steels with 12% Chromium and variable contents of Nickel
NASA Astrophysics Data System (ADS)
Bordeasu, I.; Popoviciu, M. O.; Mitelea, I.; Ghiban, B.; Ghiban, N.; Sava, M.; Duma, S. T.; Badarau, R.
The running time of hydraulic machineries in cavitation conditions, especially blades and runners, depend on both chemical composition and mechanical properties of the used steels. The researches of the present paper have as goal to obtain new materials with improved behavior and reduced costs. There are given cavitation erosion results upon eight cast steels with martensite as principal structural constituent. The chromium content was maintained constant at approximate 12% but the nickel content was largely modified. The change of chemical content resulted in various proportions of austenite, martensite and ferrite and also in different cavitation erosion behavior. From the eight tested steels four have greater carbon content (approximately 0.1%) and the other four less carbon content (approximate 0.036%). All steels were tested separately in two laboratory facilities: T1 with magnetostrictive nickel tube (vibration amplitude 94 ?m, vibration frequency 7000 ▒ 3% Hz, specimen diameter 14 mm and generator power 500 W) and T2 is respecting the ASTM G32-2010 Standard (vibration amplitude 50?m, vibration frequency 20000 ▒ 1% Hz, specimen diameter 15.8 mm and generator power 500 W). Analyzing the results it can be seen that the cavitation erosion is correlated with the mechanical properties in the way shown in 1960 by Hammitt and Garcia but is influenced by the structural constituents.
Investigation of aluminum-steel joint formed by explosion welding
NASA Astrophysics Data System (ADS)
Kovacs-Coskun, T.; Volgyi, B.; Sikari-Nagl, I.
Explosion welding is a solid state welding process that is used for the metallurgical joining of metals. Explosion cladding can be used to join a wide variety of dissimilar or similar metals [1]. This process uses the controlled detonation of explosives to accelerate one or both of the constituent metals into each other in such a manner as to cause the collision to fuse them together [2]. In this study, bonding ability of aluminum and steel with explosion welding was investigated. Experimental studies, microscopy, microhardness, tensile and bend test showed out that, aluminum and steel could be bonded with a good quality of bonding properties with explosion welding.
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, CLAD COUNTER WEIGHT, WATER SPAN RAISED OUT OF VIEW - Cape Cod Canal Lift Bridge, Spanning Cape Cod Canal, Buzzards Bay, Barnstable County, MA
Stainless-steel elbows formed by spin forging
NASA Technical Reports Server (NTRS)
Large seamless austenitic stainless steel elbows are fabricated by spin forging /rotary shear forming/. A specially designed spin forging tool for mounting on a hydrospin machine has been built for this purpose.
Machinability of a Stainless Steel by Electrochemical Discharge Microdrilling
NASA Astrophysics Data System (ADS)
Cotea??, Margareta; Schulze, Hans-Peter; Pop, Nicolae; Be?liu, Irina; Sl?tineanu, Lauren?iu
Due to the chemical elements included in their structure for ensuring an increased resistance to the environment action, the stainless steels are characterized by a low machinability when classical machining methods are applied. For this reason, sometimes non-traditional machining methods are applied, one of these being the electrochemical discharge machining. To obtain microholes and to evaluate the machinability by electrochemical discharge microdrilling, test pieces of stainless steel were used for experimental research. The electrolyte was an aqueous solution of sodium silicate with different densities. A complete factorial plan was designed to highlight the influence of some input variables on the sizes of the considered machinability indexes (electrode tool wear, material removal rate, depth of the machined hole). By mathematically processing of experimental data, empirical functions were established both for stainless steel and carbon steel. Graphical representations were used to obtain more suggestive vision concerning the influence exerted by the considered input variables on the size of the machinability indexes.
Mechanical properties of friction stir welded 11Cr-ferritic/martensitic steel
NASA Astrophysics Data System (ADS)
Yano, Y.; Sato, Y. S.; Sekio, Y.; Ohtsuka, S.; Kaito, T.; Ogawa, R.; Kokawa, H.
Friction stir welding was applied to the wrapper tube materials, 11Cr-ferritic/martensitic steel, designed for fast reactors and defect-free welds were successfully produced. The mechanical and microstructural properties of the friction stir welded steel were subsequently investigated. The hardness values of the stir zone were approximately 550 Hv (5.4 GPa) with minimal dependence on the rotational speed, even though they were much higher than those of the base material. However, tensile strengths and elongations of the stir zones were high at 298 K, compared to those of the base material. The excellent tensile properties are attributable to the fine grain formation during friction stir welding.
Influence of Short Austenitization Treatments on the Mechanical Properties of Low-Alloy Steels for Hot Forming Applications
NASA Astrophysics Data System (ADS)
Holzweissig, Martin Joachim; Lackmann, Jan; Konrad, Stefan; Schaper, Mirko; Niendorf, Thomas
The current work elucidates an improvement of the mechanical properties of tool-quenched low-alloy steel by employing extremely short austenitization durations utilizing a press heating arrangement. Specifically, the influence of different austenitization treatmentsŚinvolving austenitization durations ranging from three to 15 secondsŚon the mechanical properties of low-alloy steel in comparison to an industrial standard furnace process was examined. A thorough set of experiments was conducted to investigate the role of different austenitization durations and temperatures on the resulting mechanical properties such as hardness, bending angle, tensile strength, and strain at fracture. The most important finding is that the hardness, the bending angle as well as the tensile strength increase with shortened austenitization durations. Furthermore, the ductility of the steels exhibits almost no difference following the short austenitization durations and the standard furnace process. The enhancement of the mechanical properties imposed by the short heat treatments investigated, is related to a refinement of microstructural features as compared to the standard furnace process.
Influence of Short Austenitization Treatments on the Mechanical Properties of Low-Alloy Steels for Hot Forming Applications
NASA Astrophysics Data System (ADS)
Holzweissig, Martin Joachim; Lackmann, Jan; Konrad, Stefan; Schaper, Mirko; Niendorf, Thomas
The current work elucidates an improvement of the mechanical properties of tool-quenched low-alloy steel by employing extremely short austenitization durations utilizing a press heating arrangement. Specifically, the influence of different austenitization treatmentsŚinvolving austenitization durations ranging from three to 15 secondsŚon the mechanical properties of low-alloy steel in comparison to an industrial standard furnace process was examined. A thorough set of experiments was conducted to investigate the role of different austenitization durations and temperatures on the resulting mechanical properties such as hardness, bending angle, tensile strength, and strain at fracture. The most important finding is that the hardness, the bending angle as well as the tensile strength increase with shortened austenitization durations. Furthermore, the ductility of the steels exhibits almost no difference following the short austenitization durations and the standard furnace process. The enhancement of the mechanical properties imposed by the short heat treatments investigated, is related to a refinement of microstructural features as compared to the standard furnace process.
Microstructure and properties of laser-borided 41Cr4 steel
NASA Astrophysics Data System (ADS)
Kulka, M.; Makuch, N.; Pertek, A.
Laser-boriding, instead of diffusion-boriding, was applied to formation of boride layers on 41Cr4 steel. The microstructure and properties of these layers were compared to those obtained after typical diffusion-boriding. Three zones characterized the microstructure of laser-borided layer: laser-borided zone, hardened medium-carbon zone (heat affected zone) and medium-carbon substrate without heat treatment. The through-hardened laser-borided steel was also analyzed. In this case two zones characterized the microstructure: laser-borided zone and hardened medium-carbon substrate. The microstructure of laser-borided zone consisted of eutectic mixture of borides and martensite. This phase composition (especially martensite presence) was the reason for microhardness decrease at the surface in comparison with diffusion-borided steel. However, the use of laser-boriding causes the decrease in microhardness gradient between the surface and the substrate in comparison with typical diffusion-boriding process. The value of mass wear intensity factor of the hardened laser-borided layer was comparable to that obtained in case of diffusion-boriding and through-hardening. The use of laser-borided layers instead of typical diffusion-borided layers may be advantageous under conditions of high abrasive wear of mating parts. For the experimental condition used, the laser-boriding process presented worst results concerning the fatigue strength. The cracks formed on the surface during laser re-melting were the reason for relatively quick first fatigue crack. In case of elements, which require high fatigue strength, the use of modified laser processing parameters would be necessary. The better results should be obtained by increasing of tracks overlapping. Although the cohesion of laser-borided layer was sufficient, the diffusion-borided layer showed a better cohesion.
Assessment of mechanical properties and phase-structural state in corrosion-resistant steels under static and low-cycle loading
V. I. Vitvitskii; V. I. Tkachev; M. F. Berezhnitskaya; R. V. ChepilÆ
The use of an austenite stability factor provides (calculated from chromium and nickel equivalents) a quantitative assessment\\u000a of phase-structural state in corrosive-resistant steels by their chemical composition. Based on the austenite stability factors,\\u000a a correlation has been established between mechanical properties of the steels under static loading. The low-cycle fatigue\\u000a life is proposed to be determined from the chemical composition
Effects of Notch Shape and Specimen Thickness on Drop-Weight Tear Test Properties of API X70 and X80 Line-Pipe Steels
Sang Yong Shin; Byoungchul Hwang; Sunghak Lee; Ki Bong Kang
In the present study, effects of notch shape and specimen thickness on drop-weight tear test (DWTT) properties of API X70\\u000a and X80 line-pipe steels fabricated by varying hot-rolling conditions were investigated. The DWTT was conducted on the rolled\\u000a steels, and the results were discussed in comparison with the Charpy V-notch (CVN) impact test and crack-tip opening angle\\u000a (CTOA) test data.
Evolution of magnetic properties of Fe-Mn and Fe-Mn-Cr steels with different stability of austenite during plastic deformation
E. S. Gorkunov; S. V. Gladkovskii; S. M. Zadvorkin; S. Yu. MitropolÆskaya; D. I. Vichuzhanin
A complex of magnetic parameters of two-phase (?+?) and austenitic Fe-Mn and Fe-Mn-Cr steels subjected to elastic deformation\\u000a by uniaxial tension and torsion at room temperature has been studied. Regularities of changes in both the magnetic properties\\u000a of the steels with different composition and the deformation stability of austenite depending on the accumulated degree of\\u000a deformation have been revealed.
Influence of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in bicarbonate\\/carbonate buffer solution
D. G. Li; Y. R. Feng; Z. Q. Bai; J. W. Zhu; M. S. Zheng
The influences of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in NaHCO3\\/Na2CO3 buffer solution are investigated by capacitance measurement and electrochemical impedance spectroscopy (EIS). The results show that the passive film appears n-type semiconductive character; with increasing the solution temperature, the addition of chromium into carbon steel and increasing the
Mechanical properties of a Cr¢Ni¢Mo¢Al¢Ti maraging steel in the process of martensitic transformation
K Nagayama; T Terasaki; K Tanaka; F. D Fischer; T Antretter; G Cailletaud; F Azzouz
Mechanical properties of a Cr¢Ni¢Mo¢Al¢Ti maraging steel are studied experimentally in the process of martensitic transformation. The transformation-start and -finish temperatures are determined from the dilatometric curves under a tensile, compressive or shear hold stress. An anomalous temperature-dependence of the yield stress is investigated. By checking the closing of the dilatometric loop in a full heating¢annealing¢cooling thermal cycle under the
Structural and mechanical properties of radiofrequency N2\\/H2 cold plasma-nitrided C38 carbon steel
F. Z. Bouanis; F. Bentiss; M. Traisnel; C. Jama
C38 carbon steel has been nitrided by radiofrequency cold plasma discharge with the aim to study the effect of gas composition on structural and mechanical properties of nitrided substrates. The plasma nitriding was carried out on unheated substrates, using two different gas mixtures (75% N2\\/25% H2 and 25% N2\\/75% H2) for 8 h of plasma treatment. Electron Probe Microanalysis (EPMA)
Influence of coating thickness and temperature on mechanical properties of steel deposited with Co-based alloy hardfacing coating
Hongxia Deng; Huiji Shi; Seiji Tsuruoka
Hardfacing is widely used to improve the performance of components exposed to severe service conditions. In this paper, this surface modification was evaluated for heat-resistance steel DIN X45CrSi9-3 deposited with Co-based alloy Stellite 12 by the plasma-transferred arc welding (PTAW). The microscopic properties of the deposition coating, including the microstructure, the chemical phases, and the distribution of element, were first
Effect of yttrium addition on the microstructure and mechanical properties of ODS RAF steels
NASA Astrophysics Data System (ADS)
Auger, M. A.; de Castro, V.; Leguey, T.; TarcĒsio-Costa, J.; Monge, M. A.; Mu±oz, A.; Pareja, R.
An oxide dispersion strengthened (ODS) alloy with nominal composition Fe-14Cr-2W-0.3Ti-0.24Y (wt.%) was produced by mechanical alloying using elemental powders, and subsequent hot isostatic pressing. The microstructure of the material and characteristics of the oxide particle dispersion were investigated by electron microscopy. The effect of heat treatments on the microhardness and tensile properties at room temperature was also studied. The results show that a fine dispersion of Y-O-rich nanoparticles is achieved, together with larger (Cr, Ti)-rich precipitates. The absence of Ti is apparent in the majority of these nanoparticles, in contrast with reported results for ODS Ti-modified steels processed with Y2O3 addition.
Electrochemical codeposition of sol-gel films on stainless steel: controlling the chemical and physical coating properties of biomedical implants.
Okner, Regina; Favaro, Gregory; Radko, Anna; Domb, Abraham Jacob; Mandler, Daniel
The electrochemically assisted codeposition of sol-gel thin films on stainless steel is described. Specifically, electrodeposition of films based on aminopropyltriethoxysilane (APTS), and its codeposition with propyltrimethoxysilane (PrTMOS) and phenyltrimethoxysilane (PhTMOS) has been accomplished by applying negative potentials. The latter increases the concentration of hydroxyl ions on the stainless steel surface and thus catalyzes the condensation and deposition of the sol-gel films. The films were characterized by profilometry, electrochemical impedance spectroscopy (EIS), alternating current voltammetry (ACV), goniometry, atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM and SEM analysis of codeposited APTS:PrTMOS films disclosed the structural changes induced by altering the deposition solution composition and the applied potential. Codeposited APTS:PhTMOS did not show any structural differences from their electrodeposited homopolymers, while Nano Scratch Test clearly revealed the changes in the elastic and adhesion properties, suggesting the formation of an APTS:PhTMOS composite. EIS of the films showed good resistance towards penetration of hydrophilic species, such as hexacyanoferrate. ACV measurements of the homo and codeposits showed the decrease of the interfacial capacity as a result of the electrochemical deposition. In essence, controllable sol-gel films with tunable chemical and physical properties based on controlling the combination of the precursors, pH and electrochemical properties can be electrodeposited on conducting surfaces. The application of this approach has been demonstrated by coating a stainless steel coronary stent. PMID:20877869
Influence of Alloying Elements on the Thermodynamic Properties of Titanium in Molten Steel
NASA Astrophysics Data System (ADS)
Yoshikawa, Takeshi; Morita, Kazuki
The influences of alloying elements of chromium, nickel, manganese, molybdenum, copper, and oxygen on the thermodynamic property of titanium in molten iron were investigated at 1873 K to improve control of the formation of titanium compounds in the steelmaking processes. At a certain titanium potential controlled by the coexistence of Ti3O5 and Ti2O3 with steel, the interaction parameters between alloying elements and titanium in molten iron were determined as follows. \\varepsilon ^{{{text{Mn}}}}_{{{text{Ti}}}} = - 27.4( ▒ 0.66),quad \\varepsilon ^{{{text{Cr}}}}_{{{text{Ti}}}} = 5.33( ▒ 0.84),quad \\varepsilon ^{{{text{Ni}}}}_{{{text{Ti}}}} = - 3.93( ▒ 0.51),quad \\varepsilon ^{{{text{Mo}}}}_{{{text{Ti}}}} = 5.76( ▒ 0.69),quad \\varepsilon ^{{{text{Cu}}}}_{{{text{Ti}}}} = 3.44( ▒ 0.69) Through the investigation of titanium deoxidation equilibria in molten iron, the activity coefficient of titanium and the first-order interaction parameter between oxygen and titanium were determined as follows: ? _{{{text{Ti}}}}^{ circ} = 0.0215(▒0.00062),quad \\varepsilon ^{{{text{Ti}}}}_{{text{O}}} = - 160(▒10) Also, titanium deoxidation of molten 304 stainless steel was measured and compared with the calculated results using the determined interaction parameters.
Tensile Properties and Work Hardening Behavior of Laser-Welded Dual-Phase Steel Joints
NASA Astrophysics Data System (ADS)
Farabi, N.; Chen, D. L.; Zhou, Y.
The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in the heat-affected zone was caused by partial vanishing and tempering of the pre-existing martensite. The extent of softening was much larger in the DP980-welded joints than in the DP600-welded joints. Despite the reduction in ductility, the ultimate tensile strength (UTS) remained almost unchanged, and the yield strength (YS) indeed increased stemming from the appearance of yield point phenomena after welding in the DP600 steel. The DP980-welded joints showed lower YS and UTS than the base metal owing to the appearance of severe soft zone. The YS, UTS, and strain hardening exponent increased slightly with increasing strain rate. While the base metals had multi-stage strain hardening, the welded joints showed only stage III hardening. All the welded joints failed in the soft zone, and the fracture surfaces exhibited characteristic dimple fracture.
Degradation of mechanical properties of stainless steel cladding due to neutron irradiation and thermal aging
Haggag, F.M.
Thermal aging of three-wire series-arc stainless steel weld overlay cladding at 288{degrees}C for 1605 h resulted in an appreciable decrease (16%) in the Charpy V-notch (CVN) upper-shelf energy (USE), but the effect on the 41-J transition temperature shift was very small (3{degrees}C). The combined effect following neutron irradiation at 288{degrees}C to a fluence of 5 X 10{sup 19} neutrons/cm{sup 2} (>1 MeV) was a 22% reduction in the USE and a 29{degrees}C shift in the 41-J transition temperature. The effect of thermal aging on tensile properties was very small. However, the combined effect of irradiation and aging was an increase in the yield strength (6 to 34% at test temperatures from 288 to -125{degrees}C) and no apparent change in ultimate tensile strength or total elongation. Neutron irradiation reduced the initiation fracture toughness (J{sub {kappa}}) much more than did thermal aging alone. However, irradiation slightly decreased the tearing modulus but no reduction was caused by thermal aging alone. The effects of long-term thermal exposure times (20,000 and 50,000 h) will be investigated when the specimens become available. Also, long-term thermal exposure of the three-wire cladding as well as type 308 stainless steel weld materials at 343{degrees}C is in progress.
Microstructures and mechanical properties of melt-quenched ferritic stainless steels
NASA Astrophysics Data System (ADS)
Minemura, T.; Ikuta, I.; Ishihara, J.
Using the twin-roller type melt-quenching technique, the effects of rapid solidification on the microstructures and mechanical properties of ferrite have been examined in 17 pct Cr and 17 pct Cr-M steels where M = Ti, Nb, Si, or Al. The melt-quenched 17 pct Cr steels have the columnar and equiaxed grains which become finer with decreasing of specimen thickness. But the yield strength of these steels, which is about 0.48 GPa, remains almost unchanged with grain size refinement, contrary to predictions based on Hall-PetchÆs relationship. The columnar structure of the melt-quenched 17 pct Cr-M steels is very fine on alloying with Ti and Si, while it is slightly coarse on alloying with Nb and Al. The hardness, yield strength, and fracture strength of these 17 pct Cr-M steels increase with increased amount of alloying element, these maximum values being about 460 DPN, 1.0 GPa, and 1.35 GPa, respectively, for 17 pct Cr- 6 pct Si steel, in the ductile compositional range. These are suitable values for a fine-gauge material having high hardness and strength as well as good ductility.
The inhibition of mild steel corrosion in acidic medium by 2,2?-bis(benzimidazole)
NASA Astrophysics Data System (ADS)
Abboud, Y.; Abourriche, A.; Saffaj, T.; Berrada, M.; Charrouf, M.; Bennamara, A.; Cherqaoui, A.; Takky, D.
A new corrosion inhibitor, namely 2,2'-bis(benzimidazole) has been synthesised and its inhibiting action on the corrosion of mild steel in acidic bath (1 M HCl) has been investigated by various corrosion monitoring techniques, such as corrosion weight loss test and potentiodynamic polarisation. The results of the investigation show that this compounds have fairly good inhibiting properties for steel corrosion in hydrochloric acid, and is a mixed inhibitor in (1 M HCl). The adsorption of this inhibitor is also found to obey the Langmuir adsorption isotherm.
Effect of sintering atmosphere on properties of porous stainless steel for biomedical applications.
Dudek, Agata; W?odarczyk, Renata
This study discusses manufacturing of metallic biomaterials by means of powder metallurgy with consideration for their unquestionable advantages, i.e. opportunities of obtaining materials with controllable porosity. The paper focuses on properties of 316 L stainless steel obtained using the method of powder metallurgy with respect to compacting pressure and sintering atmosphere. All the specimens were compacted at 700, 400 and 225 MPa, and sintered at 1250 ░C. In order to analyze the sintering atmosphere, three different media were used: dissociated ammonia, hydrogen and vacuum. The study covered sintering density, porosity, microstructure analysis and corrosion resistance. The proposed method of powder metallurgy allowed for obtaining materials with predictable size and distribution of pores, depending on the parameters of sinter preparation (compaction force, sinter atmosphere). High corrosion resistance of the materials (sintering in the atmosphere of hydrogen and in vacuum) and high porosity in the sinters studied offer opportunities for using them for medical purposes. PMID:25428092
Specimen size effects on tensile properties of neutron-irradiated steels
NASA Astrophysics Data System (ADS)
Kohyama, A.; Hamada, K.; Matsui, H.
In the research and development of miniaturized specimen technology, consideration of specimen size effect is the key issue. In this work, tensile tests were studied with variations of specimen size around the standard mini-tensile specimen in the Japanese fusion materials program. The materials used were JPCA (modified 316 SS) and JFMS (modified 10Cr-2Mo dual phase steel). Microstructure has been controlled to clarify the effect of grain size for the former and the effect of ferrite/martensite ratio for the latter. Neutron irradiations of post-irradiation deformation response, microstructure prior to and after deformation were examined by transmission electron microscopy. The effects of specimen thickness and aspect ratio (thickness/width) on tensile properties are studied. New scaling equations to evaluate valid yield strength and tensile strength from small specimens with thickness less than the critical thickness, tc, are proposed. The origins of specimen size effects from a microstructural viewpoint are also discussed.
Influence of explosive density on mechanical properties of high manganese steel explosion hardened
NASA Astrophysics Data System (ADS)
Hu, Xiaoyan; Shen, Zhaowu; Liu, Yingbin; Liu, Tiansheng; Wang, Fengying
The explosion hardening tests of high manganese steel were carried out by using two kinds of explosives of the same composition but different density, respectively. The detonation velocities were tested and the relevant mechanical properties were studied. The results show that the stronger single impulse acting on the specimen, the more hardness of surface increases and the more impact toughness decreases. Compared with the explosive of 1.48 g/cm3 density, the hardness, elongation rate, and impact toughness of the sample for triple explosion with explosive of 1.38 g/cm3 density are larger at the same hardening depth. In addition, the tensile strength of the sample for triple explosion with density of 1.38 g/cm3 is higher from the surface to 15 mm below the surface hardened.
Antimicrobial and osteogenic properties of silver-ion-implanted stainless steel.
Qin, Hui; Cao, Huiliang; Zhao, Yaochao; Jin, Guodong; Cheng, Mengqi; Wang, Jiaxin; Jiang, Yao; An, Zhiquan; Zhang, Xianlong; Liu, Xuanyong
Prevention of implant loosening and infection is crucial to orthopedic and dental surgeries. In this work, the surface of stainless steel (SS) was modified by silver-sourced plasma immersion ion implantation (Ag-PIII). Metallic silver nanoparticles with various diameters and distributions were fabricated on the SS surfaces after treatment with Ag-PIII for 0.5 and 1.5 h, respectively. The osteogenic activity and antimicrobial properties of SS before and after Ag-PIII treatment were evaluated using in vitro and in vivo tests. The results demonstrated that Ag-PIII treatment not only promoted the antibacterial activity of SS but also enhanced the osteogenic differentiation of human bone marrow stromal cells. PMID:25952114
Effect of microadditions on the structure and properties of powder carbon steel
L. N. D'yachkova; N. P. Glukhova; E. V. Zvonarev
1.Additions of alkali metals accelerate the diffusion of carbon in iron, particularly at low sintering temperatures, increase the carbon concentration of the steel, improve the strength properties at all temperatures studied, and produce a more uniform and stable structure.2.Increasing the amount of alkali metal produces some increase in strength if sodium or potassium are added, but no change if lithium
Two-dimensional magnetic properties of silicon steel sheet subjected to a rotating field
Masato Enokizono; Takashi Todaka; Shinichi Kanao; Johannes Sievert
A study of the two-dimensional rotational magnetic properties of a steel sheet are discussed. These are measured making use of the vector relation between magnetic field strength H and magnetic flux density B. The results of this study lead to the following main conclusions: the permeability tensor becomes a full matrix under rotating flux; the off-diagonal terms of the permeability
Microstructure and antibacterial properties of microwave plasma nitrided layers on biomedical stainless steels
Li-Hsiang Lin; Shih-Chung Chen; Ching-Zong Wu; Jing-Ming Hung; Keng-Liang Ou
Nitriding of AISI 303 austenitic stainless steel using microwave plasma system at various temperatures was conducted in the present study. The nitrided layers were characterized via scanning electron microscopy, glancing angle X-ray diffraction, transmission electron microscopy and Vickers microhardness tester. The antibacterial properties of this nitrided layer were evaluated. During nitriding treatment between 350░C and 550░C, the phase transformation sequence
TIG welding of Uranus 45N duplex stainless steel: Changes in microstructure and properties
J M Gomez de Salazar; A. Urena; M Jesus Alvarez
The purpose of this paper is to study the development of mechanical properties and microstructure in three TIG welded joints, as a function of the distance to the weld centreline and the welding conditions. Three different heat inputs have been analysed for Uranus 45N duplex stainless steel for the purpose of studying microstructures in weld metals and HAZs, such as
Influence of C, Mn and Ni Contents on Microstructure and Properties of Strong Steel
Cambridge, University of
, Department of Materials Science and Metallurgy, Pembroke Street, Cambridge CB2 3QZ, U.K. Abstract Neural elsewhere [5Ł7]. Using the composition of a commercial shielded metal arc welding (SMAW) electrode (ESAB OKInfluence of C, Mn and Ni Contents on Microstructure and Properties of Strong Steel Weld Metals
Correlation of microstructure and thermal-fatigue properties of centrifugally cast high-speed steel rolls
NASA Astrophysics Data System (ADS)
Kim, Chang Kyu; Park, Jong Il; Ryu, Jae Hwa; Lee, Sunghak
This is a study of thermal-fatigue properties in centrifugally cast high-speed steel (HSS) rolls. The thermal-fatigue mechanism was investigated, with special focus on the roll microstructure and the increase in tensile stress which led the specimens to fracture when it reached the tensile strength. The thermal-fatigue test results indicated that the thermal-fatigue life decreased with increasing maximum temperature of the thermal-fatigue cycle. The results were then interpreted based on the amount of carbides and the cyclic-softening phenomenon associated with the exposed time to elevated temperatures. The coarse intercellular carbides on the specimen surface acted as fatigue-crack initiation sites as they cleaved at a low stress level to form cracks. The roll having the lowest matrix hardness and the smallest amount of intercellular carbides, thus, showed better thermal fatigue properties than the other rolls. For the improvement of the thermal-fatigue properties of the rolls, this study suggests a homogeneous distribution of carbides by reducing the carbide segregation formed along the solidification cell boundary and by optimizing the roll compositions.
Effect of high-temperature deformation on the mechanical properties of AISI 316 stainless steel
NASA Astrophysics Data System (ADS)
Shabara, Mohammed A. N.
Accurate and reliable life predictions of mechanical components subjected to stress at elevated temperature may be difficult since the mechanical properties of the material are expected to change. The constitutive equations describing the creep behavior may also change due to softening or hardening processes caused by the applied loading conditions. In this paper the response of AISI Type 316 stainless steel at 650 degrees Celsius when subjected to a static tensile stress is examined. A testing technique has been applied to the test material to evaluate the effect of short periods of high temperature deformation on its mechanical properties. Round tensile specimens were subjected to constant tensile stress levels under high temperature of 650 degrees Celsius for periods of time varying from 2 to 8 hours. The specimens were then annealed and tested in tension under room temperature. Test results indicate that the AISI Type-316 exhibited hardening due to short period creep. Yield strength and ultimate tensile strength have increased by 58% and 20%, respectively, after 8 hours creep, over that of the virgin material. Creep was also found to cause a reduction in the ductility of the AISI Type-316 over the temperature and stress levels used in this investigation. Moreover, the changes in these properties were found to increase as creep time increased. From the present work, an empirical equation was obtained for predicting the amount of hardening in the material due to creep. Such an equation may be useful in more involved problems of combined creep and fatigue.
Improvement of resistance to oxidation by laser alloying on a tool steel
Gemellli, E.; Gallerie, A.; Caillet, M.
The goal of this work is to improve the resistance to oxidation at high temperature of a tool steel (D2) without degrading its satisfactory tribologic properties. In a recent paper, the authors showed that the combination in the same coating, of chromium and silicon can provide increased resistance to oxidation at high temperature, a combination which until then had been used only in massive alloys. The present investigation deals with a steel initially having 12% chromium. The addition of silicon to the steel surface should improve the resistance to oxidation to the minimum levels required by the steel high operating temperatures. On the other hand, it has also been shown that the chromium and carbon addition leads to the formation o hard phases [(Fe,Cr){sub 7}C{sub 3}] necessary for a good anti-wear behavior. The increase of the chromium concentration in solid solution and the presence of carbide in the coating, obtained by the addition of Cr{sub 3}C{sub 2}, should then increase not only the resistance to oxidation, but also the resistance to wear. The possibility of obtaining the same effects by the addition o silicon carbide or chromium carbide to the D2 steel surface has also been investigated.
Nitriding of austenitic stainless steel by plasma immersion ion implantation
G. A. Collins; R. Hutchings; K. T. Short; J. Tendys; X. Li; M. Samandi
Plasma immersion ion implantation (PI3Ö), in which the diffusion of nitrogen from a low pressure r.f. plasma is combined with the implantation of nitrogen ions at energies up to 45 kV, is an effective means of nitriding austenitic stainless steel. At temperatures up to 450 ░C, tribological properties can be improved without loss of corrosion resistance. In common with other
Evolution of mechanical properties of M50 bearing steel due to rolling contact fatigue
NASA Astrophysics Data System (ADS)
Allison, Bryan D.
Current bearing life models significantly under predict the life of bearings made of modern ultra-clean steels. New life models that include the constitutive response of the material are needed. However, the constitutive response of bearing steel is known to change during bearing operation. In the current study, the evolution of the mechanical properties of M50 bearing steel due to rolling contact fatigue (RCF) was investigated. A combination of M50 balls and rods were subjected to RCF testing under various conditions (e.g. number of RCF cycles, applied Hertzian stress, and interacting material). Additionally, some of the balls tested went through a proprietary mechanical process to induce compressive residual stresses over the first several hundred microns into the depth of the ball prior to RCF testing. After RCF testing, the specimens were subjected to a number of tests. First, the residual stresses within the subsurface RCF affected region were measured via x-ray diffraction. The residual stresses within the mechanically processed (MP) balls were found to not significantly change due to RCF, while a linear relationship was found between the maximum residual stress with the RCF affected zone and the Hertzian stress for the unprocessed balls. Then, the specimens were sectioned, polished, and chemically etched to study the evolution of the microstructure due to RCF. A similar relationship was found between the size of the dark etching region (DER) and the Hertzian stress. Formation of a light etching region (LER) is demonstrated to not correlate with a decrease in material strength and hardness, but it does serve as a predictor for failure due to spall. Micro-indentation was performed within subsurface to estimate the local yield stress. Micro-indentation is not able to provide information about the stress-strain response, only the yield strength. Hence, a novel method to extract and test miniature compression specimens from within the RCF affected regions of balls after RCF was developed. Using this method, it is possible to determine the full stress-strain response of material after material that has undergone RCF. The micro-hardness of the material within the RCF affected region was found to increase by nearly 10% and yield strength increased 13% when high contact stress levels were employed in fatigue experiments. It was demonstrated that the number of cycles does contribute to hardness increase, but the applied Hertzian stress is the dominant factor. Mechanical processing was found to significantly retard the rate of mechanical property evolution, implying that it would also significantly improve the life. Similarly, it was observed that the rate of hardening is slower when silicon nitride is used to interact with the M50 specimen than another M50 component. This supports the idea that hybrid bearings last longer than more traditional all-steel bearings. Finally, an empirical model of the evolution of the constitutive response of the bearing material within the RCF affected region was developed based on the results of these analyses. This model can be used to predict the constitutive response of the material within the RCF affected region of an M50 steel ball, given the initial hardness, number of RCF cycles, and applied Hertzian stress. Further, it is now possible to solve the local yield strength as a function of depth within the RCF affected region given these same parameters.
Influence of Aging and Thermomechanical Treatments on the Mechanical Properties of a Nanocluster-Strengthened Ferritic Steel
Z. W. Zhang; C. T. Liu; Y. R. Wen; A. Hirata; S. Guo; G. Chen; M. W. Chen; Bryan A. Chin
This study investigated the effect of aging and thermomechanical treatments on the mechanical properties of a nanocluster-strengthened\\u000a ferritic steel, Fe-1.5Mn-2.5Cu-4.0Ni-1.0Al (wt pct). The effect of thermomechanical treatments on the microhardness and tensile\\u000a properties were measured at room temperature and correlated with microstructural features. Cu-rich precipitates were characterized\\u000a by transmission electron microscopy and were found to coarsen slowly during long-time aging.
Diffusion of Aluminum Into Steel Substrates By Means Of Hot Dip Aluminizing
Husain, Hishamuddin Hj.; Razak Daud, Abdul [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Daud, Muhamad [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)
Surface coating is an efficient and economical method to obtain desirable material surfaces properties. As compared to other coating techniques, hot dip coating can be considered as the most economical way to protect steel surfaces. Hot dip aluminizing technique was investigated in this study. Experiments have been conducted on the mild steel substrates with 10 mm diameter. The substrates were dipped into the molten aluminum maintained at temperature 750 deg. C for 5, 10, 15, 20, 25 and 30 minutes. Optical microscopy, scanning electron microscope and energy dispersive X-ray spectroscopy were used in this investigation. From the microstructure observation, it showed the appearance of intermetallic layer covered by the top layer of Al on the mild steel substrate increased with the increase in dipping time. The result of EDX analysis revealed the existence of Fe and Al in form of new Al-Fe phase. This indicated the possible formation of the intermetallic layers.
Formation of Wear Resistant Steel Surfaces by Plasma Immersion Ion Implantation
Maendl, S.; Rauschenbach, B. [Institute fuer Oberflaechenmodifizierung, 04303 Leipzig (Germany)
Plasma immersion ion implantation (PIII) is a versatile and fast method for implanting energetic ions into large and complex shaped three-dimensional objects where the ions are accelerated by applying negative high voltage pulses to a substrate immersed in a plasma. As the line-of-sight restrictions of conventional implanters are circumvented, it results in a fast and cost-effective technology. Implantation of nitrogen at 30 - 40 keV at moderate temperatures of 200 - 400 deg. C into steel circumvents the diminishing thermal nitrogen activation encountered, e.g., in plasma nitriding in this temperature regime, thus enabling nitriding of additional steel grades. Nitride formation and improvement of the mechanical properties after PIII are presented for several steel grades, including AISI 316Ti (food industry), AISI D2 (used for bending tools) and AISI 1095 (with applications in the textile industry)
Predictions of the Mechanical Properties and Microstructure Evolution of High Strength Steel in Hot Stamping
NASA Astrophysics Data System (ADS)
Cui, Junjia; Lei, Chengxi; Xing, Zhongwen; Li, Chunfeng; Ma, Shumei
Hot stamping is an innovative operation in metal-forming processes which virtually avoids the cracking and wrinkling of high strength steel (HSS) sheets. Examining the phase transformation and mechanical properties of HSS by means of experiments is challenging. In this article, a numerical model of the hot stamping process including forming, quenching, and air cooling was developed to reveal the microstructure evolution and to predict the final mechanical properties of hot-stamped components after multi-process cycles. The effects of the number of process cycles and the holding times on the temperature of HSS were examined using the model. The microstructure evolution of HSS under variable holding times is illustrated. The mechanical properties, particularly hardness and tensile strength, were predicted. It was found that the martensitic content increased with increasing holding time, and the martensitic content of the formed component at the flange and end was higher than for the sidewall, and lowest for the bottom. The hardness trend was consistent with the martensitic content. After six process cycles, the predictive errors of the model for hardness and tensile strength were acceptable for practical applications in engineering. Comparison between the predicted results and the experiment results showed that the developed model was reliable.
Effect of Vanadium Nitride Precipitation on Martensitic Transformation and Mechanical Properties of CrMnNi Cast Austenitic Steels
NASA Astrophysics Data System (ADS)
Wendler, Marco; Reichel, Benedikt; Eckner, Ralf; Fabrichnaya, Olga; Kr³ger, Lutz; Wei▀, Andreas; Mola, Javad
The microstructural evolution and mechanical properties of two cast Fe-15Cr-6Mn-3Ni-0.5Si-0.2N-0.1C (concentrations in wt pct) steels containing no vanadium and 0.65 wt pct vanadium were investigated under uniaxial tensile loading for room temperature (RT) and 373 K (100 ░C). The alloy development was focused on the formation of nanosized vanadium nitride precipitates in the austenite to serve as obstacles to dislocation motion. The austenitic steels exhibited transformation- and twinning-induced plasticity (TRIP/TWIP) effects and the planar glide of dislocations in the austenite. The triggering stress for the RT strain-induced ? ???' formation increased by 190 MPa, and the transformation occurred at higher strain levels due to the presence of VN precipitates. The occurrence of the TWIP effect during tensile testing at 373 K (100 ░C) of both steels resulted in engineering strains above 50 pct. The yield strength (YS) of the VN-containing steel was 420 MPa at RT, 52 MPa higher than the vanadium-free alloy. The difference increased to 59 MPa at 373 K (100 ░C) with the VN-containing alloy exhibiting a YS of 311 MPa.
Effect of low-temperature ultrasonic treatment on the properties of steel 12Kh18N10T
V. S. Biront; V. A. Sushchikh; F. K. Sidorov
1.Low-temperature ultrasonic treatment of quenched austenitic steel 12Kh18N10T induces the development of the martensitic transformation.2.The change in the properties of the steel during low-temperature ultrasonic treatment points to isothermal kinetics of the martensitic transformation that develops.3.The appearance of martensite phase (up to 25%) substantially increases the saturation magnetization of the steel, the length of the samples, and the electrical resistivity.
Effects of an inorganic coating on the structure and magnetic properties of a 1 wt. % silicon steel
Prabhat K. Rastogi; Yong-Wu Kim
Various organic and inorganic coatings are used for electrical steels to improve their punchability and interlaminar resistance. However, very little information is available in the literature on the effect of these coatings on structure and magnetic properties of electrical steels. In this study, the influence of a commercial mono-aluminum-phosphate coating was investigated for a 1.0 wt. % silicon steel. It
Effect of loading type on fatigue properties of high strength bearing steel in very high cycle regime
W. Li; T. Sakai; Q. Li; L. T. Lu; P. Wang
Very high cycle fatigue tests under axial loading at frequencies of 95Hz and 20kHz were performed to clarify the effect of loading type on fatigue properties of a high strength bearing steel in combination with experimental result of this steel under rotating bending. As a result, this steel represents the single P-S-N (probabilistic-stress-life) curve characteristics for surface-induced fracture and interior
Dynamic fracture toughness and Charpy impact properties of an AISI 403 martensitic stainless steel
NASA Astrophysics Data System (ADS)
Sreenivasan, P. R.; Ray, S. K.; Mannan, S. L.; Rodriguez, P.
Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness ( KId) from the load-time traces obtained in instrumented tests of unprecracked Charpy V-notch (CVN) specimens are considered. The estimated KId values show reasonable agreement with those obtained from instrumented drop-weight and precracked Charpy tests. Also, except in the upper transition and uppershelf regions, the ASME KIR curve is generally conservative (i.e. gives lower KId values) when compared to the above KId estimates. The conservatism of the ASME KIR at the upper transition and uppershelf temperatures needs verification/validation. The lowest KId values estimated at the lower shelf temperatures for the above steel, namely, 33-42 MPa?m are in good agreement with the reported values of 35-50 MPa?m for the same steel in the literature.
Effect of admixtures on mechanical properties of steel-fibre-reinforced polymer high-strength concrete
NASA Astrophysics Data System (ADS)
Huang, Pei-yan; Zheng, Shun-chao; Guo, Wenying; Deng, Jun
In this study, a new kind of steel fibre reinforced polymer high-strength concrete was developed for bridge structures. This material is component of C60 concrete and some admixtures, including steel fibre, polymer latex, fly ash, etc. An experimental study was performed to determine the mixture ratio of the new material and test the fundamental mechanical performances, such as the tensile and compressive strength. Scanning electron microscope (SEM) investigation and mechanism analysis were employed to study the effect of the admixtures on the material properties. The results show that the strength, toughness and crack resistance of the C60 concrete are improved if appropriate content of steel fibre, polymer latex and fly ash are added.
Mechanical properties of thermally aged cast stainless steels from shippingport reactor components.
Chopra, O. K.; Shack, W. J.; Energy Technology
Thermal embrittlement of static-cast CF-8 stainless steel components from the decommissioned Shippingport reactor has been characterized. Cast stainless steel materials were obtained from four cold-leg check valves, three hot-leg main shutoff valves, and two pump volutes. The actual time-at-temperature for the materials was {approx}13 y at {approx}281 C (538 F) for the hot-leg components and {approx}264 C (507 F) for the cold-leg components. Baseline mechanical properties for as-cast material were determined from tests on either recovery-annealed material, i.e., annealed for 1 h at 550 C and then water quenched, or material from the cooler region of the component. The Shippingport materials show modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength because of relatively low service temperatures and ferrite content of the steel. The procedure and correlations developed at Argonne National Laboratory for estimating mechanical properties of cast stainless steels predict accurate or slightly lower values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and JIC of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predicted the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y and the KRB reactor pump cover plate (CF-8) after {approx}8 y of service.
Mechanical properties of thermally aged cast stainless steels from Shippingport reactor components
Chopra, O.K.; Shack, W.J. [Argonne National Lab., IL (United States)
Thermal embrittlement of static-cast CF-8 stainless steel components from the decommissioned Shippingport reactor has been characterized. Cast stainless steel materials were obtained from four cold-leg check valves, three hot-leg main shutoff valves, and two pump volutes. The actual time-at-temperature for the materials was {approximately}13 y at {approximately}281 C (538 F) for the hot-leg components and {approximately}264 C (507 F) for the cold-leg components. Baseline mechanical properties for as-cast material were determined from tests on either recovery-annealed material, i.e., annealed for 1 h at 550 C and then water quenched, or material from the cooler region of the component. The Shippingport materials show modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength because of relatively low service temperatures and ferrite content of the steel. The procedure and correlations developed at Argonne National Laboratory for estimating mechanical properties of cast stainless steels predict accurate or slightly lower values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predicted the mechanical properties of the Ringhals 2 reactor hot and crossover-leg elbows (CF-8M steel) after service of {approximately} 15 y and the KRB reactor pump cover plate (CF-8) after {approximately} 8 y of service.
Fatigue Properties and Fracture Mechanism of Steel Coated with Diamond-Like Carbon Films
NASA Astrophysics Data System (ADS)
Akebono, Hiroyuki; Kato, Masahiko; Sugeta, Atsushi
Diamond-like carbon (DLC) films have attracted much attention in many industrial fields because of their excellent tribological properties, high hardness, chemical inertness and biocompatibility. In order to examine the fatigue properties and to clear the fracture mechanism of DLC coated materials, AISI4140 steel coated with DLC films by using unbalanced magnetron sputtering method was prepared and two types of fatigue test were carried out by using a tension and compression testing machine with stress ratio -1 and a bending testing machine with stress ratio -1 with a focused on the fatigue crack behavior in detail. The fracture origin changed from the slip deformation to micro defects at surface whose size didn't affect the fatigue crack initiation behavior in the case of Virgin series because the hard coating like DLC films make the defect sensitivity of coated material higher. However, DLC series indicated higher fatigue strengths in finite life region and fatigue limit compared with Virgin series. From the continuously observation by using a plastic replicas technique, it is clear that there are no noticeable differences on fatigue crack propagation rate between the Virgin and DLC series, however the fatigue crack initiation of DLC series was delayed significantly by existence of DLC films compared with Virgin series.
Microstructure-Property Relationship in the Thermomechanically Processed C-Mn-Si-Nb-Al-(Mo) TRIP Steels before and after PS/BH Treatment
Timokhina, I. B. [Monash University, Australia; Enomoto, M [Ibaraki University, Japan; Miller, Michael K [ORNL; Pereloma, E. V. [University of Wollongong, Wollongong, Australia
The effect of prestraining and bake hardening (PS/BH) on the development of microstructures and mechanical properties in thermomechanically processed transformation-induced plasticity (TRIP) steels with additions of Nb, Mo, and Al was studied by atom probe tomography (APT) and transmission electron microscopy (TEM). An increase in number density and sizes of clusters and nanoscale precipitates was observed in both steels but was more significant in the Nb-Al-Mo steel than in the Nb-Al steel. This increase could be explained by the possible fast diffusion of Nb and Mo atoms at low temperatures, as was observed for surface diffusivity. The contributions of cluster strengthening and precipitation strengthening to the yield strength increment after PS/BH were estimated.
Factors Affecting on Mechanical Properties of Soft Martensitic Stainless Steel Castings
NASA Astrophysics Data System (ADS)
Iwabuchi, Yoshitaka
This paper details the factors affecting mechanical properties of soft martensitic stainless steel castings that have lower carbon contents and increased nickel contents of up to 6% compared with normal martensitic stainless steel castings. The effect of alloying elements and impurities on the microstructural features and tempering characteristics was considered in detail, with special reference to reverted austenite and temper embrittlement. The mechanical properties were also investigated, and it was shown that the best combination of strength and toughness is obtained when tempered at around 900K. Addition of Mo was shown to improve toughness degradation due to slow cooling from the tempering temperature. Lowering P and S contents leads to superior toughness and fatigue properties. The threshold stress intensity range was shown to decrease with increasing stress ratio, depending on P content.
Effect of Annealing Temperature on Microstructure and Mechanical Properties of Bulk 316L Stainless Steel with Nano- and Micro-crystalline Dual Phases
NASA Astrophysics Data System (ADS)
La, Peiqing; Wei, Fuan; Lu, Xuefeng; Chu, Chenggang; Wei, Yupeng; Wang, Hongding
Microstructures and mechanical properties of 316L stainless steels with dual phases austenite prepared by an aluminothermic reaction casting were explored. It is found that the steels consist of nano- and micro-crystalline austenite phases, a little ? ferrite and contaminations. Before and after annealing at 1073 K and 1273 K (800 ░C and 1000 ░C), average grain sizes of the nanocrystalline austenite phase are about 32, 31, 38 nm, respectively. Tensile strength increases first from 371 to 640 MPa and then decreases to 454 MPa. However, elongation ratio increases gradually from 16 to 23 and then 31 pct after annealing. The results illustrate that the steel after annealing at 1073 K (800 ░C) has better properties, also indicating that combination of dual nano- and micro-crystalline austenite phase is conductive to improving tensile properties of materials.
Microstructure-property relationships and constitutive response of plastically graded case hardened steels
NASA Astrophysics Data System (ADS)
Klecka, Michael A.
Case hardened materials, popularly used in many demanding engineering applications such as bearings, gears, and wear/impact surfaces, have high surface hardness and a gradient in material properties (hardness, yield strength, etc.) as a function of depth; therefore, they behave as plastically graded materials. In the current study, two different commercially available case carburized steels along with two through hardened steels are characterized to obtain relationships among the volume fraction of subsurface carbides, indentation hardness, elastic modulus, and yield strength as a function of depth. A variety of methods including microindentation, nanoindentation, ultrasonic measurements, compression testing, rule of mixtures, and upper and lower bound models are used to determine the relationships for elastic modulus and compare the experimental results with model predictions. In addition, the morphology, composition, and properties of the carbide particles are also determined. The gradient in hardness with depth in graded materials is commonly determined using microindentation on the cross-section of the material which contains the gradation in microstructure or composition. In the current study, a novel method is proposed to predict the hardness gradient profile using solely surface indentations at a range of loads. The method does not require the graded material to be sectioned, and has practical utility in the surface heat-treatment industry. For a material with a decreasing gradient in hardness, higher indent loads result in a lower measured hardness due to the influence of the softer subsurface layers. A power-law model is presented which relates the measured surface indentation hardness under increasing load to the subsurface gradient in hardness. A coordinated experimental and numerical study is presented to extract the constitutive response of graded materials, utilizing relationships between hardness, plastic deformation, and strain hardening response. The average plastic strain induced by an indent is shown to be an effective measure of the representative plastic strain, which is used in order to relate hardness to yield strength in both virgin and plastically deformed materials. It is shown that the two carburized steels contain gradients in yield strength, but constant strain hardening exponent with depth. The resulting model of material behavior is used to characterize the influence of specific gradients in material properties on the surface indentation behavior under increasing indentation loads. It is also shown that the response of the material is not greatly influenced by strain hardening exponent, while a gradient in strain hardening ability only has minimal impact. Gradients in elastic properties are also shown to have negligible influence for a fixed gradient in hardness. The depth of subsurface plastic deformation is shown to increase with sharper gradients in hardness, but is not altered by gradients in elastic properties. The proposed approach is not specific to case hardened materials and can be used to determine the subsurface hardness gradient for any graded material.
Tribological properties evaluation of AISI 1095 steel chromized at different temperatures
Jyh-Wei Lee; Hsi-Chun Wang; Jai-Lin Li; Chao-Chih Lin
Pack chromization process provides a surface modified coating on steel surface with high hardness, corrosion and temperature resistance. AISI 1095 carbon steels were chromized to form chromium¢iron nitride and carbides on surface by pack cementation process at 850 and 900 ░C for 1¢9 h, respectively. Chromized layer with an outer (Cr,Fe)2N1-x and inner (Cr,Fe)23C6 and (Cr,Fe)7C3 phases were observed. The
Enhanced corrosion resistance properties of radiofrequency cold plasma nitrided carbon steel: Gravimetric and electrochemical results
F. Z. Bouanis; F. Bentiss; M. Traisnel; C. Jama
Cold plasma nitriding treatment was performed to improve the corrosion resistance of C38 carbon steel. Nitriding process was conducted using a radiofrequency nitrogen plasma discharge for different times of treatment on non-heated substrates. The modification of the corrosion resistance characteristic of the C38 steel due to the treatment in acid medium (1M HCl) were investigated by gravimetric and electrochemical tests
Fatigue Properties of Spot Welded and Spot Weld-Bonded Joints of Steel Sheet
Tomoyuki Fujii; Keiichiro Tohgo; Yukinori Suzuki; Takahiro Yamamoto; Yoshinobu Shimamura; Yoshifumi Ojima
In this paper, fatigue tests are carried out on spot welded and spot weld-bonded joints of mild steel and ultra-high strength steel plates. The fatigue strength of the spot weld-bonded joints is higher than that of the spot welded joints. On the spot weld-bonded specimens, the strain distribution around the bonded area during fatigue tests is measured by using strain
Evaluation of Gigacycle Fatigue Properties of Austenitic Stainless Steels Using Ultrasonic Fatigue Test
Kyouhei Takahashi; Takeshi Ogawa
Ultrasonic fatigue tests have been performed in austenitic stainless steel, SUS316NG, in order to investigate giga-cycle fatigue strength of pre-strained materials, i.e. 5, 10 and 20% tensile pre-strains and -20% compressive pre-strain. The pre-strains were applied before specimen machining. The austenitic stainless steels are known to exhibit remarkable self-heating during the fatigue experiment. Therefore, heat radiation method was established by
Austenitic stainless steels layers deposited by laser cladding on a mild steel : realization and characterization
The present work reports on 18-10 (AISI 304 grade) and 18-12-Mo (AISI 316 grade) stainless steel coatings produced'by laser powder cladding technique.Clad layers of uniform thicknesses have been produced through partially overlapping single cladding tracks. The clad layers thus obtained show excellent adherence, few porosities and good chemical homogeneity. The microstructure is dendritic or most often cellular. The 304 clad
Axisymmetric guided wave scattering by cracks in welded steel pipes
W. Zhuang; A. H. Shah; S. K. Datta
Scattering of axisymmetric guided waves by cracks and weldments of anisotropic bonding material in welded steel pipes is investigated in this paper by a hybrid method employing finite element and modal representation techniques. The study is motivated by the need to develop a quantitative ultrasonic technique to distinguish flaws and bonding materials in welded cylindrical structures. Numerical results for reflection
The structure, properties and a resistance to abrasive wear of railway sections of steel with a different pearlite morphology
K. Aniolek; J. Herian
The article presents the characteristics of pearlite rail steels used in the construction of railways. The article discusses the influence of isothermal annealing process parameters on the pearlite morphology and properties of the R260 steel. The pearlite structure with a diverse pearlite morphology was obtained in the physical modeling of the isothermal annealing on the 3800 Gleeble Simulator. After the
E. Baunķ; C. Chovet; B. Leduey; C. Bonnet
The use of (very) high strength steels for the design of high performance steel structures is highly promising as they can allow for substantial savings due to the thickness reduction of structural parts. The application of these steels for structural design, however, is not yet fully developed as limitations are imposed by design codes currently in effect. In addition, when
Perfluorocarbon thin films and polymer brushes on stainless steel 316L for control of interfacial properties
Kruszewski, Kristen M.
Perfluorocarbon thin films and polymer brushes were formed on stainless steel 316L (SS316L) to control the surface properties of the metal oxide. Substrates modified with the films were characterized using diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), contact angle analysis, atomic force microscopy (AFM), and cyclic voltammetry (CV). Perfluorooctadecanoic acid (PFOA) was used to form thin films by self-assembly on the surface of SS316L. Polypentafluorostyrene (PFS) polymer brushes were formed by surface initiated polymerization using SAMs of 16-phosphonohexadecanoic acid (COOH-PA) as the base. PFOA and PFS were effective in significantly reducing the surface energy and thus the interfacial wetting properties of SS316L. The SS316L control exhibited a surface energy of 38 mN/m compared to PFOA and PFS modifications, which had surface energies of 22 and 24 mN/m, respectively. PFOA thin films were more effective in reducing the surface energy of the SS316L compared to PFS polymer brushes. This is attributed to the ordered PFOA film presenting aligned CF3 terminal groups. However, PFS polymer brushes were more effective in providing corrosion protection. These low energy surfaces could be used to provide a hydrophobic barrier that inhibits corrosion of the SS316L metal oxide surface. PMID:21631123
Microstructure, Mechanical and Corrosion Properties of Friction Stir-Processed AISI D2 Tool Steel
NASA Astrophysics Data System (ADS)
Yasavol, Noushin; Jafari, Hassan
In this study, AISI D2 tool steel underwent friction stir processing (FSP). The microstructure, mechanical properties, and corrosion resistance of the FSPed materials were then evaluated. A flat WC-Co tool was used; the rotation rate of the tool varied from 400 to 800 rpm, and the travel speed was maintained constant at 385 mm/s during the process. FSP improved mechanical properties and produced ultrafine-grained surface layers in the tool steel. Mechanical properties improvement is attributed to the homogenous distribution of two types of fine (0.2-0.3 ?m) and coarse (1.6 ?m) carbides in duplex ferrite-martensite matrix. In addition to the refinement of the carbides, the homogenous dispersion of the particles was found to be more effective in enhancing mechanical properties at 500 rpm tool rotation rate. The improved corrosion resistance was observed and is attributed to the volume fraction of low-angle grain boundaries produced after friction stir process of the AISI D2 steel.
On the influence of surfactant over friction properties of steel
NASA Astrophysics Data System (ADS)
Upadhyay, R. K.; Kumaraswamidhas, L. A.
Surfactant wetting properties are important for any tribological system. In order to explore these properties the influence of four surfactant i.e. sodium hexametaphosphate (SHMP); zinc dithiodiphosphate (ZDDP); sodium dodecyl sulphate (SDS); and cetrimonium bromide (C-TAB); on the friction behaviour of physical vapour deposition (PVD) coated surfaces were studied using pin on disk tribometer. Anionic, cationic and non-ionic surfactants are dispersed in oil/water medium. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and X-ray diffraction (XRD) analysis was performed to obtain the surface morphology, chemical composition and structure of the material.
Comparative studies on shielding properties of some steel alloys using Geant4, MCNP, WinXCOM and experimental results
NASA Astrophysics Data System (ADS)
Singh, Vishwanath P.; Medhat, M. E.; Shirmardi, S. P.
The mass attenuation coefficients, ?/? and effective atomic numbers, Zeff of some carbon steel and stainless steel alloys have been calculated by using Geant4, MCNP simulation codes for different gamma ray energies, 279.1 keV, 661.6 keV, 662 keV, 1115.5 keV, 1173 keV and 1332 keV. The simulation results of Zeff using Geant4 and MCNP codes have been compared with possible available experimental results and theoretical WinXcom, and good agreement has been observed. The simulated ?/? and Zeff values using Geant4 and MCNP code signifies that both the simulation process can be followed to determine the gamma ray interaction properties of the alloys for energies wherever analogous experimental results may not be available. This kind of studies can be used for various applications such as for radiation dosimetry, medical and radiation shielding.
Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.
Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Sķverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves
A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films. PMID:22516111
Tensile properties of the NLF reduced activation ferritic\\/martensitic steels after irradiation in a fast reactor spectrum to a maximum dose of 67 dpa
Stuart A. Maloy; M. R. James; T. J. Romero; M. B. Toloczko; R. J. Kurtz; A. Kimura
The NLF series of steels are reduced activation ferritic martensitic (RAFM) steels that are a part of the Japanese program to produce a suitable reduced activation ferritic martensitic steel for the ITER project. Published reports on the NLF steels after about 35 dpa at 400 ░C by Kurishita et al., indicate that these steels have similar strength and better ductility
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
2. DETAIL OF BUILDER'S PLATE: 'SUPERSTRUCTURE BUILT BY STROBEL STEEL CONSTRUCTION CO., CHICAGO, ILL., 1913, SUBSTRUCTURE BUILT BY FITZSIMONS & CONNELL D&D CO., CHICAGO, ILL.' - Chicago River Bascule Bridge, Grand Avenue, Spanning North Branch Chicago River at Grand Avenue, Chicago, Cook County, IL
Microstructure, Mechanical Properties, and Unlubricated Sliding Wear Behavior of Air-Cooled MnSiCrB Cast Steels
NASA Astrophysics Data System (ADS)
Luo, Kaishuang; Bai, Bingzhe
Two medium carbon low-alloy MnSiCrB cast steels containing different Si contents (0.5 and 1.5 wt.%) were designed, and the effects of Si contents on the microstructure, mechanical properties, and unlubricated sliding wear behavior of the cast steels after air-cooling from 850 ░C and subsequent tempering at 220 ░C was studied. The results show that the microstructure of the cast steel containing 0.5 wt.% Si consists of granular bainite and lower bainite/martensite multi-phase. In the cast steel containing 1.5 wt.% Si, granular bainite was not observed. The microstructure consists of carbide-free bainite/martensite multi-phase. Excellent hardenability can be obtained at both low and high Si levels. The cast steel containing 0.5 wt.% Si exhibits excellent combination of strength, ductility, and impact toughness superior to the cast steel containing 1.5 wt.% Si. Also, the wear-resistance of the former steel is better than that of the latter in the unlubricated sliding wear condition. The air-cooled MnSiCrB cast steel containing low Si levels, with excellent mechanical properties and wear-resistance, is a potential high-performance and low-cost wear-resistant cast steel for unlubricated sliding wear condition.
Thermal and Tribological Analysis of the Dry Sliding Steel-steel Couple Traversed by an Electrical Current
NASA Astrophysics Data System (ADS)
Boubechou, C.; Bouchoucha, A.; Zaidi, H.; Mouadji, Y.
This study concerns a thermal and tribological analysis of the dry sliding steel-steel couple traversed by an electrical current. The tests were carried out by using a tribometer pin-disc under ambient air environment. The dry friction and wear of this contact are studied with different parameters such as normal load, electrical current and sliding speed (maintained constant V = 0.5 m/s). The test duration is 20 mn. The experimental results obtained show that these parameters have a more or less significant effect on the tribological behavior of the couple. Indeed, the oxidation phenomenon, the particles of wear resulting from this oxidation, their composition, their morphology and their thermal-mechanical properties, under certain conditions, play an important role and determine the life service of this couple. To highlight the effect of these parameters, theoretical calculations based on the theories of Archard and Holm have been done. These calculations allowed us to evaluate the order of magnitude of the mechanical, geometrical, thermal and electrical parameters. The discussion of the results is mainly based on these calculations, optical and SEM observations as well as other phenomena resulting from the friction process.
Influence of Microstructural Inhomogeneity and Residual Stress on Very High Cycle Fatigue Property of Clean Spring Steel
NASA Astrophysics Data System (ADS)
Li, Wei; Sakai, Tatsuo; Wang, Ping
The present study investigated the very high cycle fatigue (VHCF) properties of a spring steel SUP7-T386 under the conditions of surface grinding and electro-polishing by performing the axial loading test at a stress ratio of -1. The influence of the microstructural inhomogeneity (MI) generated in the process of heat treatment and the residual stress induced by surface grinding on the VHCF properties was discussed. This steel with surface grinding exhibits the continuously descending S-N characteristics, corresponding to the surface flaw-induced failure at high stress level and the interior flaw-induced failure at low stress level. Otherwise, with surface electro-polishing, it exhibits continuously descending S-N characteristics with lower fatigue strength, but only corresponding to the surface flaw-induced failure even at low stress level. Compared with the evaluated maximum inclusion size of about 11.5 ?m, the larger MI size and the compressive residual stress play a key role in determining fatigue failure mechanism of this steel under axial loading in the VHCF regime. From the viewpoint of fracture mechanics, MI-induced crack growth behavior belongs to the category of small crack growth, and threshold stress intensity factors controlling surface and interior crack growth are evaluated to be 2.85 and 2.51 MPa m1/2, respectively. The predicted maximum MI size of about 27.6 ?m can be well used to evaluate surface and interior fatigue limit of this steel under axial loading in the VHCF regime, combined with the correction of residual stress.
Fatigue Properties of Stainless Steel Lap Joints. Spot welded, adhesive bonded, weldbonded, laser welded and clinched joints of stainless steel sheets-a review of their fatigue properties
Hans Nordberg
The type of joints covered are i) spot welded stainless to stainless and to galvanised carbon steel, ii) adhesive bonded stainless to stainless, iii) weld bonded stainless to stainless, iv) laser welded stainless to stainless and to galvanised carbon steel, v) clinched stainless to stainless steel. The materials studied are AISI 301 and 304 stainless steel and high strength duplex
Interaction of Benzimidazoles and Benzotriazole: Its Corrosion Protection Properties on Mild Steel in Hydrochloric Acid
NASA Astrophysics Data System (ADS)
Ramya, K.; Mohan, Revathi; Joseph, Abraham
Synergistic hydrogen-bonded interaction of alkyl benzimidazoles and 1,2,3-benzotrizole and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies, and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach is used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect, and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E HOMO, E LUMO, and gap energy (? E). 1,2,3-Benzotrizole interacts with benzimidazoles derivatives up to a bond length of approximately 1.99 ┼. This interaction represents the formation of a hydrogen bond between the 1,2,3-benzotrizole and benzimidazoles. This synergistic interaction of 1,2,3-benzotrizole and benzimidazole derivatives offers extended inhibition efficiency toward mild steel in hydrochloric acid.
[Corrosion of pipe steel samples and conjugated conversion of sulfur compounds by thiobacteria Halothiobacillus neapolitanus DSM 15147].
Vatsurina, A V; Esikova, T Z; Kholodenko, V P; Va?nshte?n, M B; Dubkova, V I
The kinetics of conversion of sulfur compounds by Halothiobacillus neapolitanus DSM 15147 bacteria was studied in the presence of steel samples. It was shown that the presence of steel altered the known pathway of sulfur compound oxidation by thiobacteria. Production of atomic hydrogen via the interaction between biogenic sulfuric acid and steel enhanced secondary production of intermediates and decreased the content of sulfate produced previously. The process was accompanied by pH elevation and continuation of intense growth of the thiobacterium culture. Thiobacteria formed a corrosive medium, which caused metal destruction. The protective properties of anticorrosive coatings 225 LS and 640 mk were tested. It was shown that these coatings protected steel from the destructive effect of biogenic sulfuric acid. PMID:16240657
Catalytic coatings on stainless steel prepared by sol¢gel route
Dimitri Truyen; Matthieu Courty; Pierre Alphonse; Florence Ansart
Stainless steel (flat and microstructured) substrates have been coated with sol¢gel catalysts made up of metal nanoparticles (Rh, Ni, Pt) dispersed on alumina and alumina¢ceria supports. The aluminum monohydroxyde (boehmite) sols were synthesized by hot hydrolysis\\/peptization of an aluminum alkoxide (Yoldas method). It is shown that the rheological properties of the sol, especially the thixotropy, play a key role on
Measurement of irradiation effects in a RPV steel by ball indentation technique and magnetic Barkhausen noise
In-Sup Kim; Duck-Gun Park; Thak-Sang Byun; Jun-Hwa Hong
Effects of neutron dose on the mechanical and magnetic properties of a SA508-3 nuclear pressure vessel steel were investigated by using ball indentation test technique and magnetic Barkhausen noise (BN) measurements. The samples were irradiated in a research reactor up to 1018 n\\/cm2 (E>1 MeV) at 70 ░C. The yield strength and flow curve were evaluated from the indentation load-depth
Surface modification of superaustenitic and maraging stainless steels by low-temperature gas-phase carburization
Johannes Gentil
Low-temperature gas-phase carburization of 316L austenitic stainless steel was developed in recent years by the Swagelok company. This process generates great mechanical and electrochemical surface properties. Hardness, wear resistance, fatigue behavior, and corrosion resistance are dramatically improved, while the formation of carbides is effectively suppressed. This new technique is of technical, economical, but especially of scientific interest because the surface
Mechanical properties¢microstructure correlation in neutron irradiated heat-affected zones of austenitic stainless steels
R. Stoenescu; R. Schaeublin; D. Gavillet; N. Baluc
The effects of neutron irradiation on austenitic stainless steels, usually used for the manufacturing of internal elements of nuclear reactors (e.g. the core shrouds), are the alteration of the microstructure, and, as a consequence, of the mechanical properties. The present study is aimed at extending knowledge upon the impact of neutron-irradiation on the heat-affected zone of welded materials, which was
Welding-induced mechanical properties in austenitic stainless steels before and after neutron irradiation
R. Stoenescu; R. Schõublin; D. Gavillet; N. Baluc
The effects of neutron irradiation on the mechanical properties of welded joints made of austenitic stainless steels have been investigated. The materials are welded AISI 304 and AISI 347, so-called test weld materials, irradiated with neutrons at 573K to doses of 0.3 and 1.0dpa. In addition, an AISI 304 from a decommissioned pressurised water reactor, so-called in-service material, which had
Influence of post irradiation annealing on the mechanical properties and defect structure of AISI 304 steel
W. Van Renterghem; A. Al Mazouzi; S. Van Dyck
The effect of post irradiation annealing on the mechanical properties and the radiation induced defect structure was investigated on stainless steel, of type AISI 304, that was irradiated up to 24dpa in the decommissioned Chooz A reactor. The material was investigated both in the as-irradiated state as well as after post irradiation annealing. In the as-irradiated specimen the typical radiation
Fatigue properties and failure characterization of spot welded high strength steel sheet
Xin Long; Sanjeev K. Khanna
Fatigue properties and failure characterization of high strength spot welded steels, such as DP600 GI, TRIP600-bare and HSLA340Y GI, have been conducted. Tensile shear and coach peel samples have been used in this investigation. HSLA340Y GI samples were used as the baseline material for comparison. Microhardness was measured to study the hardness change across the weld nugget. Under low load
Tensile and fatigue properties of 17-4 PH stainless steel at high temperatures
Jui-Hung Wu; Chih-Kuang Lin
The tensile and high-cycle fatigue properties for 17-4 PH* stainless steels in three different conditions were investigated\\u000a at temperatures ranging from room temperature to 400 C. Results indicated that the yield strength and fatigue strength for\\u000a the three conditions at a given temperature took the following order: condition H900 > condition A> condition H1150. The yield\\u000a strength of each condition
Weld microstructure development and properties of precipitation-strengthened martensitic stainless steels
J. A. Brooks; W. R. Jr. Garrison
The weld microstructural evolution, mechanical properties and solidification cracking susceptibility of three precipitation-strengthened martensitic stainless steels--PH 13-8 Mo, Custom 450 and 15-5 PH--were investigated. Liquid tin quenching of gas tungsten arc welds revealed that all three welds solidified as single-phase ferrite with a high degree of microsegregation. However, during further solidification and cooling almost complete homogenization occurred as a result
Effect of Grain Refinement on the Mechanical Properties of a Nickel- and Manganese-Free High Nitrogen Austenitic Stainless Steel
NASA Astrophysics Data System (ADS)
Akbari, Alireza; Mohammadzadeh, Roghayeh
Grain coarsening due to the high temperature exposure deteriorates mechanical properties of the high nitrogen austenitic stainless steels (HNASSs) produced by solution nitriding. To improve mechanical properties, the grains of nickel and manganese-free Fe-23Cr-2.4Mo-1.2N HNASS plates fabricated by pressurized solution nitriding were refined using a two-stage heat treatment process. Structural and mechanical properties were investigated using X-ray diffraction, optical microscopy, scanning and transmission electron microscopy, hardness and tensile testing and compared with that of the conventional AISI 316L steel. The results show that the as-produced HNASS exhibits uniform deformation up to failure without necking and brittle inter-granular fracture. By grain refinement, the yield and tensile strengths as well as the elongation to failure are increased by 17.8, 21.2, and 108.3 pct, respectively, as compared to the as-produced HNASS. However, despite more than a double increase in tensile toughness and elongation to failure, the brittle inter-granular fracture is not suppressed. The HNASSs plastically deform through formation of straight slip bands. TEM observations indicate development of planar arrays of dislocations in tensile-deformed HNASSs. The enhancement in tensile strength and toughness by grain refinement is discussed on the basis of straight slip bands formation, number of dislocations in pile-ups, and incompatibility strain developed between adjacent grains.
Early detection of steel rebar corrosion by acoustic emission monitoring
Zdunek, A.D.; Prine, D.; Li, Z.; Landis, E.; Shah, S. [Northwestern Univ., Evanston, IL (United States)
Acoustic emission monitoring was performed in a unique way on concrete specimens containing reinforcing steel and the acoustic emission events correlated with the presence of rebar corrosion. Verification of rebar corrosion was done by galvanic current, half-cell potential, and electrochemical analysis. Results showing the early onset of rebar corrosion from acoustic emission are presented.
Stack cracking by hydrogen embrittlement in a welded pipeline steel
M. Y. B. Zakaria; T. J. Davies
Arrays of cracks, parallel to the original plate rolling direction, were produced in a X65 microalloyed steel by hydrogen embrittlement of pipeline sections containing a weldment. A region of the heat-affected zone of the weldment was shown to have a lower yield strength (ōsoftö zone) than the surrounding material and cracking was concentrated in this throughthickness zone to produce the
Effect of bainite transformation and retained austenite on mechanical properties of austempered spheroidal graphite cast steel
NASA Astrophysics Data System (ADS)
Takahashi, Toshio; Abe, Toshihiko; Tada, Shuji
Austempered ductile iron (ADI) has excellent mechanical properties, but its Young's modulus is low. Austempered spheroidal graphite cast steel (AGS) has been developed in order to obtain a new material with superior mechanical properties to ADI. Its carbon content (approximately 1.0 pct) is almost one-third that of a standard ADI; thus, the volume of graphite is also less. Young's modulus of AGS is 195 to 200 GPa and is comparable to that of steel. Austempered spheroidal graphite cast steel has an approximately 200 MPa higher tensile strength than ADI and twice the Charpy absorbed energy of ADI. The impact properties and the elongation are enhanced with increasing volume fraction of carbon-enriched retained austenite. At the austempering temperature of 650 K, the volume fraction of austenite is approximately 40 pct for 120 minutes in the 2.4 pct Si alloy, although it decreases rapidly in the 1.4 pct Si alloy. The X-ray diffraction analysis shows that appropriate quantity of silicon retards the decomposition of the carbon-enriched retained austenite. For austempering at 570 K, the amount of the carbon-enriched austenite decreases and the ferrite is supersaturated with carbon, resulting in high tensile strength but low toughness.
Local distribution on magnetic properties in grain-oriented silicon steel sheet
NASA Astrophysics Data System (ADS)
Enokizono, Masato; Tanabe, Ikuo; Kubota, Takeshi
Grain-oriented silicon steel is the most important soft magnetic material used as core material of large transformers, large rotating machines, and pole transformers. Total loss of grain-oriented silicon steel tends to become lower with an increasing degree of texture. However, the material which has a higher degree of texture ordinarily contains larger grains, and the materials which have larger grains show higher total loss due to increased eddy current loss. As the gauge is reduced, the rate of decrease in total loss becomes lower for the thinner gauge due to increased hysteresis loss. However, the investigation of local magnetic properties due to grain situation in this sheet was not discussed from the viewpoint of the distribution of localized magnetic properties, for example, iron loss, hysteresis loop, behavior H vector (magnetic field strength) and B vector (Magnetic flux density). This paper describes the distribution of magnetic properties in high oriented silicon steel sheet, which are loss, hysteresis loop, and locus of field strength.
Characterization of aluminide coatings formed on 1.4914 and 316L steels by hot-dipping in molten aluminium
Barbier, F.; Manuelli, D.; Bouche, K. [CEA-CEREM/DECM/SCECF, Fontenay-aux-Roses (France)] [CEA-CEREM/DECM/SCECF, Fontenay-aux-Roses (France)
Protective coatings are commonly used to extend the life of alloys in oxidation, corrosion or erosion environments encountered in various industrial fields. For example, in the fusion nuclear technology area, coatings applied to the surface of structural materials have to be developed because of the use of the liquid alloy Pb-17Li as a tritium breeder material and a coolant in future reactors. In this specific case, it is necessary to protect the steel containment from liquid metal corrosion and to prevent the loss of tritium from the coolant by diffusion/permeation through steel or elevated temperatures. Greater success has been reported for intermetallic coatings as aluminides which form protective aluminium oxide scales on steel surface. Therefore, the purpose of this work is to study aluminide coatings produced on steel substrate by hot-dipping in molten aluminium. In the present paper, 1.4914 martensitic steel and 316L austenitic stainless steel (materials suggested as structural steels for the future blanket of fusion reactors) have been studied. Some tests have also been carried out with pure metals as iron, nickel and chromium. The chemical composition, structure and growth properties of intermetallic layers formed during the interaction of materials with liquid aluminium are presented and compared.
Anisotropy of Dynamic Compressive Properties of Non-Heat-Treating Cold-Heading-Quality Steel Bars
NASA Astrophysics Data System (ADS)
Kim, Hyunmin; Kang, Minju; Bae, Chul Min; Kim, Hyoung Seop; Lee, Sunghak
In the current study, a non-heat-treating cold-heading-quality steel bar was fabricated by cold drawing of a rolled bar, and anisotropic mechanical properties of the as-rolled and cold-drawn bars were investigated by quasistatic and dynamic compressive tests of 0 deg (longitudinal)-, 45 deg-, and 90 deg (transverse)-orientation specimens. Under the dynamic compressive loading, the trend of strength variation was similar to that of the quasistatic compressive loading, while the strength level was considerably increased by the strain rate hardening effect. Stress-strain curves of the cold-drawn bar specimens showed the nearly same strain hardening behavior, irrespective of specimen orientation and strain rate, but the yield stress and compressive flow stress increased in the order of the 0 deg-, 90 deg-, and 45 deg-orientation specimens. In the 45 deg- and 90 deg-orientation specimens, the pearlite bands had the stronger resistance to the stress acting on the maximum shear stress plane than in the 0 deg-orientation specimens, thereby resulting in the higher strengths. In some dynamically compressed specimens, pearlite bands were dissolved to form bainitic microstructures. Locations of these bainitic microstructures were well matched with hemispherical-shaped heat-trap zones, which confirmed that bainitic microstructures were formed by the temperature rise occurring during the dynamic compressive loading.
Mechanical Properties of Laser Heat Treated 6 mm Thick UHSS-Steel
NASA Astrophysics Data System (ADS)
Jõrvenpõõ, Antti; Mõntyjõrvi, Kari; Merklein, Marion; mõõttõ, Antti; Hietala, Mikko; Karjalainen, Jussi
In this work abrasion resistant (AR) steel with a sheet thickness of 6 mm was heat treated by a 4 kW Nd:YAG and a 4 kW Yb:Yag-laser, followed by self-quenching. In the delivered condition, test material blank (B27S) is water quenched from 920░ C. In this condition, fully martensitic microstructure provides excellent hardness of over 500 HB. The test material is referred to AR500 from now onwards. Laser heat treatment was carried out only on top surface of the AR500 sheet: the achieved maximum temperature in the cross-section varies as a function of the depth. Consequently, the microstructure and mechanical properties differ between the surfaces and the centre of the cross-section (layered microstructure). For better understanding, all layers were tested in tensile tests. For a wide heat treatment track, the laser beam was moved by scanning. Temperatures were measured using thermographic camera and thermocouples. Laser heat treated AR500 samples were tested in hardness tests and by air bending using a press brake machine. Microstructures were studied using a light microscope and FE-SEM/SEM-EBSD. At least three kind of microstructure layers were observed: 1) Dual-Phase ferritic/martensitic (T = AC1-AC3), 2) ferritic (TśAC3) and 3) bainitic/martensitic (T>AC3).
The Effects of Cooling Mode on Precipitation and Mechanical Properties of a Ti-Nb Microalloyed Steel
NASA Astrophysics Data System (ADS)
Hu, Zhangwei; Xu, Guang; Yang, Hailin; Zhang, Chen; Yu, Ru
Laboratory experiments of a high-strength Ti-Nb microalloyed steel were conducted with two cooling modes, i.e., a large (35 ░C s-1) cooling rate in the initial stage followed by slow (8.5 ░C s-1) cooling rate (termed as FFC) and a slow (8.5 ░C s-1) cooling rate in the initial stage followed by large (35 ░C s-1) cooling rate (LFC) during cooling process. Based on the results of laboratory experiments, an industrial trial was performed with similar steel on a continuous hot strip production mill. The grain size in LFC sample (2.83 ?m) is smaller than that in FFC sample (3.80 ?m), and the volume fraction of precipitates in LFC sample (1.04%) is more than that in FFC sample (0.81%). Both results of laboratory experiments and industrial tests confirm that the strengthening effect of the LFC mode is much better than that of the FFC mode from the viewpoints of both fine-grain strengthening and precipitation strengthening. The present study provides a new approach to improve the property of microalloyed steels produced by continuous hot rolling technology.
Chromizing of ball bearing steels for extending bearing life
G. N. Dubinin; G. L. Oganesyan; V. P. Zhukov; V. A. Boikov
1.Diffusion chromizing of self-aligning bearings of steels ShKh15 and 95Kh18 enhances wear resistance and corrosion resistance of these steels.2.Diffusion chromizing makes it possible to replace stainless steel 95Kh18 by the relatively cheap steel ShKh15 with better operational properties obtained after chromizing.
Martensitic stainless steel AISI 420Śmechanical properties, creep and fracture toughness
NASA Astrophysics Data System (ADS)
Brnic, J.; Turkalj, G.; Canadija, M.; Lanc, D.; Krscanski, S.
In this paper some experimental results and analyses regarding the behavior of AISI 420 martensitic stainless steel under different environmental conditions are presented. That way, mechanical properties like ultimate tensile strength and 0.2 percent offset yield strength at lowered and elevated temperatures as well as short-time creep behavior for selected stress levels at selected elevated temperatures of mentioned material are shown. The temperature effect on mentioned mechanical properties is also presented. Fracture toughness was calculated on the basis of Charpy impact energy. Experimentally obtained results can be of importance for structure designers.
Effect of Cyclic Aging on Mechanical Properties and Microstructure of Maraging Steel 250
NASA Astrophysics Data System (ADS)
Tariq, Fawad; Naz, Nausheen; Baloch, Rasheed Ahmed
The effects of thermal cyclic aging on mechanical properties and microstructure of maraging steel 250 were studied using hardness tester, tensile testing machine, impact tester, optical, scanning electron, and stereo microscopy. Samples were solution annealed at 1093 K for 1 h followed by air cooling to form bcc martensite. Cyclic aging treatments were carried out at 753 and 773 K for varying time periods. Increase in hardness and strength with corresponding decrease in ductility and impact strength was observed with increasing aging cycles. Reverted austenite was detected by x-ray diffraction technique formed as a result of cyclic aging. The presence of reverted ? was also confirmed by EDX-SEM analysis and attributed to the formation of Mo- and Ni-rich regions which transformed to ? on cooling. Heterogeneity in composition and amount of reverted ? was found to increase with increase in aging cycles and aging time. Fractography reveals the change in fracture mode from ductile dimple-like to brittle cleavage with increase in hardness and strength due to cyclic aging.
Properties of stainless steels for fusion conductor jackets and their manufacturing techniques
Forster, S.; Komarek, P.; Nyilas, A.; Ulbricht, A. (Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Technische Physik)
This paper reports on a superconducting cable for a fusion magnet that has to be reinforced by a stainless steel jacket which envelopes the cable. The jackets are fabricated by extruded and butt welded steel sections or by composing the jacket from drawn sections with longitudinal welds. Fatigue life and fatigue crack growth rates were investigated at 10 K for embedded and surface cracks for the candidate material 316LN. Embedded cracks are more severe as compared to surface cracks. The predicted cyclic life agrees with the measured one.
Hydrogen-Induced Cracking in GMA Welds of Vanadium¢Titanium Microalloyed High Strength Steel
K. Venkatesan; R. Sivasankari; V. Balusamy; Atul Saxena; Priti Jha; Ramen Datta
High strength low alloy (HSLA) steels are developed to provide better strength, toughness, and improved weldability. These steels are often used as better alternatives for quenched and tempered steels due to the excellent combination of these properties. The beneficial properties in these steels are achieved by careful control of composition and by adopting suitably controlled thermomechanical processing (TMCP). Improved weldability
Charpy toughness and tensile properties of a neutron irradiated stainless steel submerged-arc weld cladding overlay
Corwin, W.R.; Berggren, R.G.; Nanstad, R.K.
The possibility of stainless steel cladding increasing the resistance of an operating nuclear reactor pressure vessel to extension of surface flaws is highly dependent upon the irradiated properties of the cladding. Therefore, weld overlay cladding irradiated at temperatures and fluences relevant to power reactor operation was examined. The cladding was applied to a pressure vessel steel plate by the submerged-arc, single-wire, oscillating electrode method. Three layers of cladding were applied to provide a cladding thickness adequate for fabrication of test specimens. The first layer was type 309, and the upper two layers were type 308 stainless steel. There was considerable dilution of the type 309 in the first layer of cladding as a result of excessive melting of the base plate. Specimens for the irradiation study were taken from near the base plate/cladding interface and also from the upper layers of cladding. Charpy V-notch and tensile specimens were irradiated at 288/sup 0/C to neutron fluences of 2 x 10/sup 23/ n/m/sup 2/ (E > 1 MeV). When irradiated, both types 308 and 309 cladding showed a 5 to 40% increase in yield strength accompanied by a slight increase in ductility in the temperature range from 25 to 288/sup 0/C. All cladding exhibited ductile-to-brittle transition behavior during impact testing.
Rhenium Uptake as Analogue 96Tc by Steel Corrosion Products
K.M. Krupka, C.F. Brown, H. Todd Schaef, S. M. Heald, M. M. Valenta, B. W. Arey
Static batch experiments were used to examine the sorption of dissolved perrhenate [Re(VII)], as a surrogate for pertechnetate [Tc(VII)], on corrosion products of A-516 carbon steel coupons contacted with synthetic groundwater or dilute water. After 109 days of contact time, the concentration of dissolved Re(VII) in the synthetic groundwater matrix decreased by approximately 26%; the dilute water matrix experienced a 99% decrease in dissolved Re(VII) over the same time period. Bulk x-ray diffraction (XRD) results for the corroded steel coupons showed that the corrosion products consisted primarily of maghemite, lepidocrocite, and goethite. Analyses of the coupons by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) indicated that Re was present with the morphologically complex assemblages of Fe oxide/hydroxide corrosion products for samples spiked with the highest dissolved Re(VII) concentration (1.0 mmol/L) used for these experiments. Analyses of corroded steel coupons contacted with solutions containing 1.0 mmol/L Re(VII) by synchrotron-based methods confirmed the presence of Re sorbed with the corrosion product on the steel coupons. Analyses showed that the Re sorbed on these corroded coupons was in the +7 oxidation state, suggesting that the Re(VII) uptake mechanism did not involve reduction of Re to a lower oxidation state, such as +4. The results of our studies using Re(VII) as an analogue for {sup 99}Tc(VII) suggest that {sup 99}Tc(VII) would also be sorbed with steel corrosion products and that the inventory of {sup 99}Tc(VII) released from breached waste packages would be lower than what is now conservatively estimated.
Influence of nitrogen-induced grain refinement on mechanical properties of nitrogen alloyed type 316LN stainless steel
NASA Astrophysics Data System (ADS)
Kim, Dae Whan
Tensile, fatigue, and creep tests were conducted to investigate the effect of grain refinement by the addition of nitrogen on mechanical properties of nitrogen alloyed type 316LN stainless steel. Grain size was reduced from 100 ?m to 47 ?m as nitrogen concentration was increased from 0.04% (N04) to 0.10% (N10). When nitrogen concentration was increased, there was a 20% increase in yield stress and a 14% increase in UTS, respectively. Elongation was not significantly changed with increasing nitrogen concentration. As nitrogen concentration was increased, there was a 41% increase in fatigue life and an approximately sixfold increase in the time to rupture. As grain size was reduced from 100 ?m to 47 ?m, there was an 8% increase in yield stress and a 3% increase in UTS, respectively. Elongation was little changed with decreasing grain size. As grain size was reduced from 100 ?m to 47 ?m, there was a 9% increase in fatigue life and a 23% increase in the time to rupture. The grain refinement achieved by the addition of nitrogen improved the high temperature mechanical properties of nitrogen alloyed type 316LN stainless steel but was not the main mechanism for improvement of mechanical properties.
Tensile properties of the NLF reduced activation ferritic\\/martensitic steels after irradiation in a fast reactor spectrum to a maximum dose of 67 dpa
Stuart A. Maloy; M. R. James; T. J. Romero; M. B. Toloczko; R. J. Kurtz; A. Kimura
The NLF series of steels are reduced activation ferritic¢martensitic (RAFM) steels that are a part of the Japanese program to produce a suitable reduced activation ferritic¢martensitic steel for the ITER project. Published reports on the NLF steels after about 35dpa at 400░C by Kurishita et al., indicate that these steels have similar strength and better ductility than other RAFM steels
Processing, Microstructures and Properties of a Dual Phase Precipitation-Hardening PM Stainless Steel
NASA Astrophysics Data System (ADS)
Schade, Christopher
To improve the mechanical properties of PM stainless steels in comparison with their wrought counterparts, a PM stainless steel alloy was developed which combines a dual-phase microstructure with precipitation-hardening. The use of a mixed microstructure of martensite and ferrite results in an alloy with a combination of the optimum properties of each phase, namely strength and ductility. The use of precipitation hardening via the addition of copper results in additional strength and hardness. A range of compositions was studied in combination with various sintering conditions to determine the optimal thermal processing to achieve the desired microstructure. The microstructure could be varied from predominately ferrite to one containing a high percentage of martensite by additions of copper and a variation of the sintering temperature before rapid cooling. Mechanical properties (transverse rupture strength (TRS), yield strength, tensile strength, ductility and impact toughness) were measured as a function of the v/o ferrite in the microstructure. A dual phase alloy with the optimal combination of properties served as the base for introducing precipitation hardening. Copper was added to the base alloy at various levels and its effect on the microstructure and mechanical properties was quantified. Processing at various sintering temperatures led to a range of microstructures; dilatometry was used utilized to monitor and understand the transformations and the formation of the two phases. The aging process was studied as a function of temperature and time by measuring TRS, yield strength, tensile strength, ductility, impact toughness and apparent hardness. It was determined that optimum aging was achieved at 538░C for 1h. Aging at slightly lower temperatures led to the formation of carbides, which contributed to reduced hardness and tensile strength. As expected, at the peak aging temperature, an increase in yield strength and ultimate tensile strength as well as apparent hardness was found. Aging also lead to an unexpected and concurrent increase in ductility and impact toughness. The alloys also showed an increase in strain hardening on aging. The increase in ductility varied with the v/o martensite in the microstructure and was shown to occur after short time intervals at the optimum aging temperature. Compressive strength measurements revealed that the increase in ductility was due to the relaxation of residuals stresses that occur when the high temperature austenite transforms to martensite in the dual phase microstructure. The specific volume of martensite is much larger than that of austenite so that when the transformation takes place, a compressive stress is induced in the ferrite. In the sintered state, the residual stress leads to a higher work hardening rate in tension. When the alloy is aged, the work hardening rate is reduced and the ductility is increased compared with the sintered state, even though aging increases the strength and apparent hardness.
Effect of heat treatment and plastic deformation on the structure and the mechanical properties of nitrogen-bearing 04N9Kh2A steel
NASA Astrophysics Data System (ADS)
Blinov, V. M.; Bannykh, O. A.; Lukin, E. I.; Kostina, M. V.; Blinov, E. V.
The effect of the conditions of heat treatment and plastic deformation on the structure and the mechanical properties of low-carbon martensitic nickel steel (9 wt % Ni) with an overequilibrium nitrogen content is studied. The limiting strain to failure of 04N9Kh2A steel is found to be 40% at a rolling temperature of 20░C and 80% at a rolling temperature of 900░C. Significant strengthening of the steel (?0.2 = 1089 MPa) is obtained after rolling at a reduction of 40% at 20░C. The start and final temperatures of the ? ? ? transformation on heating and those of the ? ? ? transformation on cooling are determined by dilatometry. The specific features of the formation of the steel structure have been revealed as functions of the annealing and tempering temperatures. Electron-microscopic studies show that, after quenching from 850░C and tempering at 600░C for 1 h, the structure contains packet martensite with thin interlayers of retained austenite between martensite crystals. The strength of the nitrogen-bearing 04N9Kh2A steel after quenching from 850 and 900░C, cooling in water, and subsequent tempering at 500░C for 1 h is significantly higher than that of carboncontaining 0H9 steel used in cryogenic engineering.
Adsorption Removal of Phosphorus from Aqueous Solution by Steel Slag Columns
Hua Zhang; Xuehong Zhang; Shaoyuan Bai; Yinian Zhu; Yuzhou Gong
Removal of phosphorus from aqueous solution by steel slag column and the effects of the addition of boiler slag, furnace ash and quartz sand were investigated. After the adsorption treatment by the steel slag column, the residual phosphorus concentration was less than 0.5 mg\\/L. The adsorption performance of the steel slag column could be enhanced by the addition of quartz
Mechanical properties of the European reference RAFM steel (EUROFER97) before and after irradiation at 300 ░C
NASA Astrophysics Data System (ADS)
Lucon, Enrico; Chaouadi, Rachid; Decrķton, Marc
EUROFER97 is the European candidate RAFM steel for use as a structural material in fusion energy systems. It is presently under investigation by several European laboratories, within the long term programme of EFDA (European Fusion Development Agreement). This paper presents the outcome of the mechanical characterization of this steel that has been carried out at SCK Ģ CEN (Belgian Center for Nuclear Studies), in the unirradiated condition and after irradiation during three different campaigns in the BR2 reactor (300 ░C, doses between 0.3 and 1.6 dpa). Tensile, Charpy impact, and fracture toughness specimens have been irradiated and tested, in order to obtain an experimental assessment of the main effects of neutron exposure on tensile and toughness properties; namely, irradiation hardening (increase of mechanical resistance and loss of ductility) and irradiation embrittlement (shift of ductile-to-brittle transition temperature and degradation of upper shelf energy). Comparisons with another well-known IEA reference RAFM steel, F82H, are provided.
Effects of Mo, Cr, and V Additions on Tensile and Charpy Impact Properties of API X80 Pipeline Steels
NASA Astrophysics Data System (ADS)
Han, Seung Youb; Shin, Sang Yong; Seo, Chang-Hyo; Lee, Hakcheol; Bae, Jin-Ho; Kim, Kisoo; Lee, Sunghak; Kim, Nack J.
In this study, four API X80 pipeline steels were fabricated by varying Mo, Cr, and V additions, and their microstructures and crystallographic orientations were analyzed to investigate the effects of their alloying compositions on tensile properties and Charpy impact properties. Because additions of Mo and V promoted the formation of fine acicular ferrite (AF) and granular bainite (GB) while prohibiting the formation of coarse GB, they increased the strength and upper-shelf energy (USE) and decreased the energy transition temperature (ETT). The addition of Cr promoted the formation of coarse GB and hard secondary phases, thereby leading to an increased effective grain size, ETT, and strength, and a decreased USE. The addition of V resulted in a higher strength, a higher USE, a smaller effective grain size, and a lower ETT, because it promoted the formation of fine and homogeneous of AF and GB. The steel that contains 0.3 wt pct Mo and 0.06 wt pct V without Cr had the highest USE and the lowest ETT, because its microstructure was composed of fine AF and GB while its maintained excellent tensile properties.
Mechanical properties of types 304 and 316 stainless steel after long-term aging and exposure
Horak, J.A.; Sikka, V.K.; Raske, D.T.
Because designs for Liquid Metal Fast Breeder Reactor (LMFBR) power plants include plant lifetimes to 40 years, an understanding of the mechanical behavior of the structural alloys used is required for times of approx. 2 to 2.5 x 10/sup 5/ h. Most of the alloys used for LMFBR out-of-core structures and components are in a metastable state at the beginning of plant lifetime and evolve to a more stable state and, therefore, microstructure during plant operation. We reviewed mechanical properties and microstructures after prolonged elevated-temperature exposure of types 304 and 316 stainless steel, two alloys used extensively in fast breeder systems. Aging alters properties; in particular, it decreases toughness and tensile ductility, but the properties are still adequate for service. Because stable microstructures have been reached in long-term exposures achieved so far, properties can be expected to remain adequate for service life exposures.
Tensile Properties of Under-Matched Weld Joints for 950 MPa Steel.
NASA Astrophysics Data System (ADS)
Yamamoto, Kouji; Arakawa, Toshiaki; Akazawa, Nobuki; Yamamoto, Kousei; Matsuo, Hiroki; Nakagara, Kiyoyuki; Suita, Yoshikazu
In welding of 950 MPa-class high tensile strength steel, preheating is crucial in order to avoid cold cracks, which, however, eventually increases welding deformations. One way to decrease welding deformations is lowering preheating temperature by using under-matched weld metal. Toyota and others clarify that although breaking elongation can decrease due to plastic constraint effect under certain conditions, static tensile of under-matched weld joints is comparable to that of base metal. However, there has still been no report about joint static tensile of under-matched weld joints applied to 950 MPa-class high tensile strength steel. In this study, we aim to research tensile strength and fatigue strength of under-matched weld joints applied to 950 MPa-class high tensile steel.
Formation of magnetite overlayer on nitrocarburized low-alloy steel by plasma postoxidation
M. Zlatanovi?; N. Popovi?; Ä. Bogdanov
Duplex surface treatments of steel products are known to enhance fatigue strength, tribological properties, and corrosion resistance. In combined nitriding\\/coating deposition or nitriding\\/oxidation processes, a precise control of all steps of process parameters is necessary to get the required surface architecture. The process parameters are specific for different steel grades, which require detailed investigations and surface treatment of different steel-grade
The effects of novel surface treatments on the wear and fatigue properties of steel and chilled cast iron
NASA Astrophysics Data System (ADS)
Carroll, Jason William
Contact fatigue driven wear is a principal design concern for gear and camshaft engineering of power systems. To better understand how to engineer contact fatigue resistant surfaces, the effects of electroless nickel and hydrogenated diamond-like-carbon (DLC) coatings on the fatigue life at 108 cycles of SAE 52100 steel were studied using ultrasonic fatigue methods. The addition of DLC and electroless nickel coatings to SAE 52100 bearing steel had no effect on the fatigue life. Different inclusion types were found to affect the stress intensity value beyond just the inclusion size, as theorized by Murakami. The difference in stress intensity values necessary to propagate a crack for Ti (C,N) and alumina inclusions was due to the higher driving force for crack extension at the Ti (C,N) inclusions and was attributed to differences in the shape of the inclusion: rhombohedral for the Ti (C,N) versus spherical for the oxides. A correction factor was added to the Murakami equation to account for inclusion type. The wear properties of DLC coated SAE 52100 and chilled cast iron were studied using pin-on-disk tribometry and very high cycle ultrasonic tribometry. A wear model that includes sliding thermal effects as well as thermodynamics consistent with the wear mechanism for DLCs was developed based on empirical results from ultrasonic wear testing to 108 cycles. The model fit both ultrasonic and classic tribometer data for wear of DLCs. Finally, the wear properties of laser hardened steels - SAE 8620, 4140, and 52100 - were studied at high contact pressures and low numbers of cycles. A design of experiments was conducted to understand how the laser processing parameters of power, speed, and beam size, as well as carbon content of the steel, affected surface hardness. A hardness maximum was found at approximately 0.7 wt% carbon most likely resulting from increased amounts of retained austenite. The ratcheting contact fatigue model of Kapoor was found to be useful in predicting the wear results. The empirical model of Clayton and Su and extended by Afferente and Ciavarella, also provided reasonable semi-quantitative contact fatigue life models for these steels.
Microstructure and Properties of Cast B-Bearing High Speed Steel
NASA Astrophysics Data System (ADS)
Fu, Hanguang; Ma, Shengqiang; Hou, Jianqiang; Lei, Yongping; Xing, Jiandong
Microstructure, mechanical properties, and wear resistance of B-bearing high-speed steel (HSS) roll material containing 0.90-1.00% C, 1.3-1.5% B, 0.8-1.5% W, 0.8-1.5% Mo, 4.6-5.0% Cr, 1.0-1.2% V, and 0.15-0.20% Ti were studied by means of the optical microscopy (OM), the scanning electron microscopy (SEM), x-ray diffraction (XRD), hardness, impact toughness, and pin-on-disk abrasion tests. The results showed that as-cast structure of B-bearing HSS consisted of ?-Fe-, M23(B,C)6-, M3(B0.7C0.3)-, and M2(B,C)-type borocarbides, a small quantity of retained austenite, and a small amount of TiC. The hardness and impact toughness values of as-cast B-bearing HSS reached 65-67 HRC and 80-85 kJ/cm2, respectively. There were many M23(B,C)6-precipitated phases in the matrix after tempering, and then, with increasing temperature, the amount of precipitated phases increased considerably. Hardness of B-bearing HSS gradually decreased with the increasing tempering temperature, and the change of tempering temperature had no obvious effect on impact toughness. B-bearing HSS tempered at 500 ░C has excellent wear resistance, which can be attributed to the effect of boron.
Fatigue Properties of SUS304 Stainless Steel after Ultrasonic Nanocrystal Surface Modification (unsm)
NASA Astrophysics Data System (ADS)
Zhang, K. Y.; Pyoun, Y. S.; Cao, X. J.; Wu, B.; Murakami, R.
The changing of materials surface properties method always was taken into improving the fatigue strength. In this paper, an ultrasonic nanocrystal surface modification(UNSM) technique was used on the SUS 304 stainless steel to form a nanostructured surface layer with different static load(70N, 90N, 110N, 130N) and the vibration strike number was about 20,000times/mm2. The untreated and different condition specimens fatigue strength was all tested by a dual-spindle rotating bending fatigue test machine. SPring-8(a large synchrotron radiation facility) was used to test the surface nanocrystallization components. The X-ray diffraction (XRD), the scanning electron microscopy (SEM), optical microscope and a micro-Vickers hardness tester (MVK-E3, Akashi) were separately used to get the surface residual stresses, fracture surface after fatigue testing, metallographic structure and the microhardness of the nanostructured surface layer. The result showed that martensite transformation took place on the surface of specimens, the surface residual stresses had only a small increase and some cracks occurred between the martensite layer and the austenite layer, but the fatigue strength of 90N improved 81%.
Morgan, M; Scott West, S; Michael Tosten, M
J-Integral fracture toughness tests were conducted on tritium-exposed-and-aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greater in weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite interfaces were embrittled by tritium and decay helium. Fracture toughness values decreased for both base metals and weldments with increasing decay helium content in the range tested (50-200 appm).
Improved Transformer Noise Behavior by Optimized Laser Domain Refinement at ThyssenKrupp Electrical Steel
Ludger Lahn; Chaoyong Wang; Andreas Allwardt; Thierry Belgrand; Jonathan Blaszkowski
The present paper shows the impact of different laser domain refinement variants for grain oriented electrical steel on the noise of three-phase transformer cores. The impact is evaluated as well by calculated noise on basis of magnetostriction measurements of the electrical steel sheets as by measured noise of transformer core models built from these GO electrical steel sheets. The industrially
On the formation of carbide coatings by chromizing carbon steels
L. Zancheva; M. Hillert; N. Lange; S. Seetharaman; L.-I. Staffansson
The formation of the surface layer of carbides by chromizing carbon steels has been ex-amined using a molten salt technique.\\u000a The carbide layer was analyzed with a micro-probe and examined metallographically after etching. The results were interpreted\\u000a by means of the Fe-Cr-C equilibrium phase diagram assuming that local equilibrium is es-tablished at all the phase boundaries.
Grain refinement of a nickel and manganese free austenitic stainless steel produced by pressurized solution nitriding
Mohammadzadeh, Roghayeh, E-mail: firstname.lastname@example.com; Akbari, Alireza, E-mail: email@example.com
Prolonged exposure at high temperatures during solution nitriding induces grain coarsening which deteriorates the mechanical properties of high nitrogen austenitic stainless steels. In this study, grain refinement of nickel and manganese free Fe¢22.75Cr¢2.42Mo¢1.17N high nitrogen austenitic stainless steel plates was investigated via a two-stage heat treatment procedure. Initially, the coarse-grained austenitic stainless steel samples were subjected to an isothermal heating at 700 ░C to be decomposed into the ferrite + Cr{sub 2}N eutectoid structure and then re-austenitized at 1200 ░C followed by water quenching. Microstructure and hardness of samples were characterized using X-ray diffraction, optical and scanning electron microscopy, and micro-hardness testing. The results showed that the as-solution-nitrided steel decomposes non-uniformly to the colonies of ferrite and Cr{sub 2}N nitrides with strip like morphology after isothermal heat treatment at 700 ░C. Additionally, the complete dissolution of the Cr{sub 2}N precipitates located in the sample edges during re-austenitizing requires longer times than 1 h. In order to avoid this problem an intermediate nitrogen homogenizing heat treatment cycle at 1200 ░C for 10 h was applied before grain refinement process. As a result, the initial austenite was uniformly decomposed during the first stage, and a fine grained austenitic structure with average grain size of about 20 ?m was successfully obtained by re-austenitizing for 10 min. - Highlights: Ģ Successful grain refinement of Fe¢22.75Cr¢2.42Mo¢1.17N steel by heat treatment Ģ Using the ? ? ? + Cr{sub 2}N reaction for grain refinement of a Ni and Mn free HNASS Ģ Obtaining a single phase austenitic structure with average grain size of ? 20 ?m Ģ Incomplete dissolution of Cr{sub 2}N during re-austenitizing at 1200 ░C for long times Ģ Reducing re-austenitizing time by homogenizing treatment before grain refinement.
Strengthening of high-carbon austenitic steels by deformation and aging
V. S. Zharinova; I. Ya. Georgieva; G. A. Pegushina; B. I. Beresnev; A. P. Bashchenko
1.High-temperature deformation is an effective method of improving the mechanical properties of austenitic Fe-Mn steels. Treatment with Tdef=900░ and 70% reduction in five passes provides high values of the mechanical properties without additional aging. Steel 60G12Kh9F2 is nonmagnetic after this treatment and has the following mechanical properties: sb = 1650 MPa, s0.2 = 1100 MPa, d = 26%, ? =
Investigation of Failure Mode Induced by Plasticity Localization in Dual Phase Steel by Numerical Simulation
Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.
Due to the random composite microstructure of DP steels, its failure mode is unstable and the failure mechanism is still unclear. In this paper, the failure mode and mechanism of DP steel are studied by making use of the finite element numerical method, based on real microstructure of DP steel. 2D microstructure of DP steel is recorded by SEM and is used to numerical analysis after numerical image process. The work hardening plasticity of the ferrite phase is determined by synchrotron-based high-energy X-ray diffraction (HEXRD) technique. The work hardening performance of martensite phase is calibrated and determined by the re-analysis of the uniaxial tensile test of the DP steel sample. At different loading cases, the different failure modes due to plastic localization are predicted. It was found that the local failure mode is closely related to the stress state in the material.
Microstructure and Mechanical Properties of Laser Clad and Post-cladding Tempered AISI H13 Tool Steel
NASA Astrophysics Data System (ADS)
Telasang, Gururaj; Dutta Majumdar, Jyotsna; Wasekar, Nitin; Padmanabham, G.; Manna, Indranil
This study reports a detailed investigation of the microstructure and mechanical properties (wear resistance and tensile strength) of hardened and tempered AISI H13 tool steel substrate following laser cladding with AISI H13 tool steel powder in as-clad and after post-cladding conventional bulk isothermal tempering [at 823 K (550 ░C) for 2 hours] heat treatment. Laser cladding was carried out on AISI H13 tool steel substrate using a 6 kW continuous wave diode laser coupled with fiber delivering an energy density of 133 J/mm2 and equipped with a co-axial powder feeding nozzle capable of feeding powder at the rate of 13.3 ū 10-3 g/mm2. Laser clad zone comprises martensite, retained austenite, and carbides, and measures an average hardness of 600 to 650 VHN. Subsequent isothermal tempering converted the microstructure into one with tempered martensite and uniform dispersion of carbides with a hardness of 550 to 650 VHN. Interestingly, laser cladding introduced residual compressive stress of 670 ▒ 15 MPa, which reduces to 580 ▒ 20 MPa following isothermal tempering. Micro-tensile testing with specimens machined from the clad zone across or transverse to cladding direction showed high strength but failure in brittle mode. On the other hand, similar testing with samples sectioned from the clad zone parallel or longitudinal to the direction of laser cladding prior to and after post-cladding tempering recorded lower strength but ductile failure with 4.7 and 8 pct elongation, respectively. Wear resistance of the laser surface clad and post-cladding tempered samples (evaluated by fretting wear testing) registered superior performance as compared to that of conventional hardened and tempered AISI H13 tool steel.
Plasma transferred arc boriding of a low carbon steel: microstructure and wear properties
NASA Astrophysics Data System (ADS)
Bourithis, L.; Papaefthymiou, S.; Papadimitriou, G. D.
Borided coatings on AISI 1018 steel with different boron contents were produced using plasma transferred arc (PTA) melting. The thickness of the coatings ranged from 1 to 1.5 mm and their hardness from 400 to 1600 HV. Hypoeutectic or hypereutectic compositions consisting of primary ferrite or primary Fe 2B borides, respectively, and a eutectic constituent of ?-Fe+Fe 2B were obtained. The presence of FeB attested in coatings with the highest boron contents seems to be responsible for the intergranular cracks extending from the surface of the coatings to the substrate. Crack free coatings corresponding to the minimum quantity of eutectic and with a minor quantity of FeB were subjected to pin on disk wear testing and compared to the steel of the substrate. It was found that the wear rate of the borided coatings was about four orders of magnitude lower than the wear rate of the steel substrate. A transition from mild to severe wear was observed for the steel substrate material, but it was absent in the case of the borided coatings for the entire range of the applied loads examined. It is shown that the transition in the case of steel occurs when grooving and plastic deformation is replaced by intense cracking of the material above a critical load. In the case of the borided layer the dominant wear mechanism is delamination of the eutectic, however, the platelike borides are able to support the load and remain in the mild wear range for all the loads tested. Both borided and plain steel surfaces have the same friction coefficient after a short transition period, because both develop an oxide layer leading roughly to the same tribosystem with the alumina counterbody.
Mechanical Properties of Steel Surfaces Coated with HfN/VN Superlattices
NASA Astrophysics Data System (ADS)
Escobar, C.; Villarreal, M.; Caicedo, J. C.; Aperador, W.; Prieto, P.
Mechanical and tribological evolution on 4140 steel surfaces coated with hafnium nitride/vanadium nitride [HfN/VN] n multilayer systems deposited in various bilayer periods (?) via magnetron sputtering has been exhaustively studied in this work. The coatings were characterized in terms of structural, chemical, morphological, mechanical, and tribological properties by x-ray diffraction (XRD), x-ray photo electron spectroscopy (XPS), atomic force microscopy, scanning and transmission electron microscopy, nanoindentation, pin-on-disk, and scratch tests. Moreover, the failure mode mechanisms were observed via scanning electron microscopy. The XRD results showed preferential growth in the face-centered cubic (111) crystal structure for [HfN/VN] n multilayered coatings. The best enhancement of the mechanical behavior was obtained when the bilayer period (?) 15 nm (n = 80), yielding the highest hardness (37 GPa), and elastic modulus (351 GPa). The values for the hardness and elastic modulus were 1.48 and 1.32 times greater than the coating with n = 1, respectively, as well the lowest friction coefficient (~0.15) and the highest critical load (72 N). These results indicated significant enhancements in mechanical, tribological, and adhesion properties, compared to HfN/VN multilayered systems with bilayer period (?) of 1200 nm (n = 1). This hardness and toughness enhancement in the multilayered coatings could be attributed to the different mechanisms that produce the layer formation with nanometric thickness due to the number of interfaces acting as obstacles for crack deflection and dissipation of crack energy. Due to the emergent characteristics of the synthesized multilayered, the developed adaptive coating could be considered as higher ordered tool machining systems, capable of sustaining extreme operating conditions for industrial applications.
Characterization of microstructural and mechanical properties of a reduced activation ferritic oxide dispersion strengthened steel
NASA Astrophysics Data System (ADS)
Eiselt, Ch. Ch.; Klimenkov, M.; Lindau, R.; M÷slang, A.
For specific blanket and divertor applications in future fusion power reactors a replacement of presently considered Reduced Activation Ferritic Martensitic (RAFM) steels as structural material by suitable oxide dispersion strengthened (ODS) ferritic martensitic steels would allow a substantial increase of the operating temperature from ś823 K to about 923 K. Temperatures above 973 K in the He cooled modular divertor concept necessitate the use of Reduced Activation Ferritic (RAF)-ODS-steels, which are not limited by a phase transition. The development concentrates on the ferritic ODS-steel Fe-13Cr-1W-0.3Ti-0.3Y 2O 3. The microstructures of a mechanically alloyed powder particle are observed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Ageing experiments for 1000 h and 3000 h at 1123.5 K and 1223.5 K of compacted Fe-13Cr-1W-0.3Ti-0.3Y 2O 3 were executed. The impact especially on the oxide particles in terms of segregation and decomposition effects were monitored by electron energy loss spectroscopy (EELS). Long term vacuum creep experiments have been performed with rolled Fe-13Cr-1W-0.3Ti-0.3Y 2O 3 at 923.5 K and 1023.5 K, which will be compared to reference alloys.
Effect of surface nanocrystallization on friction and wear properties in low carbon steel
Z. B Wang; N. R Tao; S Li; W Wang; G Liu; J Lu; K Lu
A nanocrystalline (nc) surface layer of about 10 ?m thick was fabricated on a low carbon steel plate by means of surface mechanical attrition treatment. The grain size is about 15 nm in the top surface layer, and it increases with an increase of depth from the treated surface. Nanoindentation measurements indicated that hardness is enhanced in the nc surface
Structure, properties, and residual stress of 304L stainless steel friction stir welds
A. P Reynolds; Wei Tang; T Gnaupel-Herold; H Prask
Alloy 304L stainless steel sheets, 3.2 mm thick, were joined by friction stir welding at a single welding speed using two different tool rotation rates. The resulting welds were overmatched relative to the base metal. Longitudinal residual stresses (tensile) were near the base metal yield strength.
17. Baltimore through truss steel bridge (1905), built by the ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
17. Baltimore through truss steel bridge (1905), built by the American Bridge Company. The bridge is 15 to 20 feet wide, with a wooden deck, and connects the Sullivan Machine Co. with the Foundry. The enclosed bridge in the background was constructed ca. 1920, and connects the Chain Machine Building with its power plant, foundry, and pattern shop. - Sullivan Machinery Company, Main Street between Pearl & Water Streets, Claremont, Sullivan County, NH
Controlling residual stresses in 52100 bearing steel by heat treatment
C. A. Stickels; A. M. Janotik
Compressive residual stresses can be induced in the surface of quenched and tempered 52100 steel (1 pct carbon, 1.5 pct chromium)\\u000a by austenitizing in a carburizing atmosphere, even though the austenitizing temperature is well below that needed to dissolve\\u000a all pri-mary carbides. The carburized surface layer contains a larger volume fraction of pri-mary carbides, more retained\\u000a austenite and is slightly
Diffusion of Aluminum Into Steel Substrates By Means Of Hot Dip Aluminizing
Hishamuddin Hj. Husain; Abdul Razak Daud; Muhamad Daud
Surface coating is an efficient and economical method to obtain desirable material surfaces properties. As compared to other coating techniques, hot dip coating can be considered as the most economical way to protect steel surfaces. Hot dip aluminizing technique was investigated in this study. Experiments have been conducted on the mild steel substrates with 10 mm diameter. The substrates were
Comparison of Microstructure and Surface Properties of AISI 1045 Steel After Quenching in Hot Alkaline Salt Bath and Oil
S. Raygan; J. Rassizadehghani; M. Askari
The effect of quenching in molten alkaline salt bath medium on the microstructure and surface properties of AISI 1045 steel\\u000a in comparison with oil was investigated. Salt bath medium used in this research contained 40% NaOH and 60% KOH with addition\\u000a of 5Āwt.% water at 205Ā░C. Hardening of 1045 steel in this medium resulted in an almost uniform microstructure, which
Validation of a small punch testing technique to characterize the cryogenic fracture properties of austenitic stainless steel welds
K. Horiguchi; Y. Shindo
This study was performed to demonstrate the feasibility of performing liquid helium temperature (4 K) small punch (SP) tests on austenitic stainless steel weld for Large Helical Device (LHD) superconducting magnets. The SP specimens (10ū10ū0.5 mm) were prepared from the different locations of electron-beam weld in type 316 stainless steel to examine the variation of the fracture properties in the
Evaluation of impact properties of weld joint of reactor pressure vessel steels with the use of miniaturized specimens
Byung Jun Kim; Hideaki Mitsui; Ryuta Kasada; Akihiko Kimura
The effects of specimen size and location of V-notch on the Charpy impact properties were investigated with different sizes of specimens, standard, CVN-1\\/2, CVN-1\\/3, and CVN-1.5Āmm, for A533B steel, low Mn, high Cu, high phosphorus (P), and high Cu\\/P steel weld joint. A part of the specimens was irradiated with neutron at 563ĀK up to 8ĀūĀ10 n\\/cm. The heat affected
Corrosion resistance properties of glow-discharge nitrided AISI 316L austenitic stainless steel in NaCl solutions
A. Fossati; F. Borgioli; E. Galvanetto; T. Bacci
Glow-discharge nitriding treatments can modify the hardness and the corrosion resistance properties of austenitic stainless steels. The modified layer characteristics mainly depend on the treatment temperature. In the present paper the results relative to glow-discharge nitriding treatments carried out on AISI 316L austenitic stainless steel samples at temperatures ranging from 673 to 773K are reported. Treated and untreated samples were
Effect of cooling method during hardening of a thermally stable bearing steel on its properties and bearing life
L. Ya. Konter; V. L. Zakharova
1.By varying the cooling during hardening it is possible to control the austenite content in secondary-hardening steel 8Kh4V9F2-Sh before dispersion hardening proceeding during isothermal soaking or tempering.2.With an increase in austenite content to 50% before dispersion hardening the hardness and strength of steel 8Kh4V9F2-Sh increases with retention of toughness and structural and dimensional stability.3.During hardening of articles made of steel
Microstructure, mechanical and fretting wear properties of TiC-stainless steel composites
Akhtar, F. [Institute of Powder Metallurgy, School of Materials Science, University of Science and Technology Beijing, 30 Xue Yuan Road, 100083, Beijing (China); Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore (Pakistan)], E-mail: email@example.com; Guo, S.J. [Institute of Powder Metallurgy, School of Materials Science, University of Science and Technology Beijing, 30 Xue Yuan Road, 100083, Beijing (China)
This study deals with the processing, microstructure, and wear behavior of TiC-reinforced stainless steel matrix composites, containing 50 to 70 wt.% TiC. Powder technology was used to successfully fabricate the composites. The microstructure of the composite was characterized by scanning electron microscopy. The microstructural study revealed that the TiC particles were distributed uniformly in the steel matrix phase. Interface debonding and microcracks were not observed in the composite. The composite hardness increased with TiC content. The fretting wear resistance of the composites was studied against high speed steel. The wear mechanisms are discussed by means of microscopical observations on the worn surfaces. The wear was severe at higher wear loads and lower TiC content. Microplowing of the stainless steel matrix was found to be the dominant wear mechanism. Heavy microplowing and rapid removal of material from the wear surface was observed at high wear load. The variation of wear loss with volume fraction and mean free path of the binder phase is also reported.
Evaluation of mechanical properties and nano-meso structures of 9-11%Cr ODS steels
NASA Astrophysics Data System (ADS)
Tanno, Takashi; Ohtsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji; Oba, Yojiro; Ohnuma, Masato; Koyama, Shinichi; Tanaka, Kenya
This study carried out mechanical tests and microstructural characterizations of several 9Cr and 11Cr-ODS tempered martensitic steels. From those results, the appropriate chemical composition range of 11Cr-ODS tempered martensitic steel was discussed from the viewpoint of high temperature strength improvement. It was shown that the residual ?-ferrite fraction in 11Cr-ODS steel was successfully controlled to the same level as the 9Cr-ODS steel, which has excellent high temperature strength, by selecting the chemical compositions on the basis of the multi-component phase diagram. The tensile strength decreased with decreasing W content from 2.0 to 1.4 wt%. On the other hand, creep strength at 973 K did not degrade by the decreasing W content. Both tensile strength and creep strength increased with increasing population of the nano-sized oxide particles. Small angle X-ray scattering analysis revealed that titanium and excess oxygen contents were key parameters in order to improve the dispersion conditions of nano-sized oxide particles.
Surface modification of SKD-61 steel by ion implantation technique
Wen, F. L.; Lo, Y.-L.; Yu, Y.-C. [Department of Mechanical and Computer Aided Engineering, and Graduate Institute of Automation and Mechatronics, St. John's University, Tamsui, Taipei 25135, Taiwan (China); Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China)
The purpose of this study is to investigate how ion implantation affects the surface characteristics and nitrogenizing depth of the thin film by the use of a NEC 9SDH-2 3 MV Pelletron accelerator that implants nitrogen ions into SKD-61 tool steels for surface modification. Nitrogen ions were implanted into the surface layer of materials so that the hardness of modified films could be improved. Also, the nitride film stripping problems of the traditional nitrogenizing treatment could be overcome by a new approach in surface process engineering. As nitrogen ions with high velocity impacted on the surface of the substrate, the ions were absorbed and accumulated on the surface of the substrate. The experiments were performed with two energies (i.e., 1 and 2 MeV) and different doses (i.e., 2.5x10{sup 15}, 7.5x10{sup 15}, and 1.5x10{sup 16} ions/cm{sup 2}). Nitrogen ions were incorporated into the interface and then diffused through the metal to form a nitride layer. Analysis tools included the calculation of stopping and range of ions in matter (SRIM), the detection of a secondary ion mass spectrometry (SIMS), and nanoindentation testing. Through the depth analysis of SIMS, the effects of the ion-implanted SKD-61 steels after heating at 550 deg. C in a vacuum furnace were examined. The nanoindenting results indicate the variation of hardness of SKD-61 steels with the various ion doses. It reaches two to three times the original hardness of SKD-61 steels.
Social Language Learning by Luc Steels
Steels, Luc
the nature/nurture debate and the discussion of a constructivist synthesis introduced by Johnson in this contribution (see Chapter 5). Labelling versus Social Grounding There are basically two main lines of thinking
Increasing the efficiency of ladle desulfurization of steel by using regenerated slags
Bigeev, V.A.; Petrov, L.V.; Vdovin, K.N.; Kotii, V.N.; Deryabin, A.V.
The volume of steel subjected to ladle desulfurization can be increased by regenerating spent synthetic slags and returning them to the production cycle. Two problems encountered in the restoration of the desulfurizing properties of the slags are the need to reduce the content of the oxides of silicon and iron and remove sulfur to the 0.03-0.06 level. Difficulties and solutions of both problems are discussed and a scheme for regeneration is proposed which uses oxidation and reduction processes and considers such parameters as ladle and furnace lining protection and metal and slag separation measures. The scheme makes the expanded efficiency of ladle desulfurization of steel with regenerated slag a realistic option and will be recommended for introduction after the individual process and design parameters have been refined.
Microstructure and Mechanical Behavior of 17-4 Precipitation Hardenable Steel Processed by Selective Laser Melting
NASA Astrophysics Data System (ADS)
Rafi, H. Khalid; Pal, Deepankar; Patil, Nachiket; Starr, Thomas L.; Stucker, Brent E.
The mechanical behavior and the microstructural evolution of 17-4 precipitation hardenable (PH) stainless steel processed using selective laser melting have been studied. Test coupons were produced from 17-4 PH stainless steel powder in argon and nitrogen atmospheres. Characterization studies were carried out using mechanical testing, optical microscopy, scanning electron microscopy, and x-ray diffraction. The results show that post-process heat treatment is required to obtain typically desired tensile properties. Columnar grains of smaller diameters (<2 Ąm) emerged within the melt pool with a mixture of martensite and retained austenite phases. It was found that the phase content of the samples is greatly influenced by the powder chemistry, processing environment, and grain diameter.
Microstructure and Mechanical Behavior of 17-4 Precipitation Hardenable Steel Processed by Selective Laser Melting
NASA Astrophysics Data System (ADS)
Rafi, H. Khalid; Pal, Deepankar; Patil, Nachiket; Starr, Thomas L.; Stucker, Brent E.
The mechanical behavior and the microstructural evolution of 17-4 precipitation hardenable (PH) stainless steel processed using selective laser melting have been studied. Test coupons were produced from 17-4 PH stainless steel powder in argon and nitrogen atmospheres. Characterization studies were carried out using mechanical testing, optical microscopy, scanning electron microscopy, and x-ray diffraction. The results show that post-process heat treatment is required to obtain typically desired tensile properties. Columnar grains of smaller diameters (<2 Ąm) emerged within the melt pool with a mixture of martensite and retained austenite phases. It was found that the phase content of the samples is greatly influenced by the powder chemistry, processing environment, and grain diameter.
Study on microstructures and properties of several kinds of hot working die steel
Fuming Wei; Zheng Huang; Yanian Zhu; Jun Zhou; Heying Yu; Ting Xu; Feng Liu; Yong Yao
This paper deals with the microstructures and properties of AISI H13(4Cr5MoSiV1), UHB QRO 90M and 4Cr3Mo2V steels, and then\\u000a discusses the means of improving the service life of hot working die. The results show that increase of quenching temperature\\u000a improves the resistance to thermal fatigue and tempering stability. Fine heat treatment process can produce fine dispersed\\u000a carbides. Shot-peening and cryogenic
Viscoelastic properties of steel 10GN2MFA at complex stressed state
NASA Astrophysics Data System (ADS)
Giginyak, F. F.; Lebedev, A. A.; Bashta, V. V.; Getmanchuk, A. V.; Titov, V. F.
Results of experimental studies of viscoelastic properties of steel 10GN2MFA at various ratios of principal stresses over the temperature range from 20 to 320 C under a stepwise loading are presented. The invariance of the generalized equilibrium stress-strain diagram with respect to the type of the stressed state for this material, as well as of the characteristics of its quasi-viscosity with respect to the type of the stressed state and the magnitude of the accumulated irreversible deformation has been substantiated experimentally.
Variation in Mechanical Properties and Heterogeneity in Microstructure of High-Strength Ferritic Steel During Mill Trial
NASA Astrophysics Data System (ADS)
Ghosh, M.; Barat, K.; Das, S. K.; Ravi Kumar, B.; Pramanick, A. K.; Chakraborty, J.; Das, G.; Hadas, S.; Bharathy, S.; Ray, S. K.
HS600 and HS800 are two new generation, high-strength advanced ferritic steels that find widespread application in automobiles. During commercial production of the same grades with different thicknesses, it has been found that mechanical properties like tensile strength and stretchability varied widely and became inconsistent. In the current endeavor, two different thicknesses have been chosen from a mill trial sample of HS600 and HS800. An in-depth structural characterization was carried out for all four alloys to explain the variation in their respective mechanical and shear punch properties. The carbon content was smaller and Ti + Mo quantity was higher in case of HS800 with respect to HS600. The microstructure of both steels consisted of the dispersion of (Ti,Mo)C in a ferrite matrix. The grain size of HS800 was little larger than HS600 due to an increased coiling temperature (CT) of the former in comparison to the latter. It was found that in case of same grade of steel with a different thickness, a variation in microstructure occurred due to change in strain, CT, and cooling rate. The strength and stretch formability of these two alloys were predominantly governed by a microalloyed carbide. In this respect, carbides with a size range above 5 nm were responsible for loosing coherency with ferrite matrix. In case of HS600, both ?5 and >5-nm size (Ti,Mo)C precipitates shared a nearly equal fraction of microalloyed precipitates. However, for HS800, >5-nm size (Ti,Mo)C carbide was substantially higher than ?5-nm size alloy carbides. The ultimate tensile strength and yield strength of HS800 was superior to that of HS600 owing to a higher quantity of microalloyed carbide with a decreased column width and interparticle distance. A higher degree of in-coherency of HS800 made the alloy prone to crack formation with low stretchability.
National Steel's by-product modifications
Kalinowsky, R.P. (National Steel Corp., Ecorse, MI (United States). Great Lakes Division); Platts, M. (Thyssen Still Otto, Pittsburgh, PA (United States))
The original 6-meter No. 5 coke battery and by-product plant operated from 1970 through 1986. Davy/Still Otto received a contract in Dec. 1990 to engineer and rebuild the by-products plant, and coal and coke material handling facilities. The rebuilt facilities began operation in Nov. 1992. Coal handling facilities were reused with repairs and modifications, such as new vibrating bin bottoms, bin blasters and variable speed belts with weigh scales for an accurate coal blend. Coke handling consists of two new fixed blade rack and pinion driven coke plows, new conveyors and screening station. The by-product plant processes 48 million cu ft/day of coke-oven gas, through two rehabilitated primary coolers, one of two rehabilitated exhausters, two new tar precipitators in parallel, two new ammonia scrubbers with secondary cooling in series and two rehabilitated light oil scrubbers in series. Coke-oven gas is used for battery underfire, boilers, hot strop mill and annealing furnaces. By-products produced and sold are light, oil, tar and sodium phenolate. Environmental facilities include ammonia stills, catalytic ammonia destruction reactors with waste heat boilers and complete gas blanketing for benzene control. All facilities are PLC and DCS controlled with data trending capability.
Effect of microstructure on the mechanical properties of a commercial 12Cr-1Mo steel (HT-9)
Lechtenberg, T.A.
The microstructure of a commercial 12Cr-1Mo steel (HT-9) and its associated effect on strength and toughness properties is being studied in a continuing program aimed at qualifying the alloy for use in fusion energy machines. Interim results show this alloy is subject to a degree of tempered martensite embrittlement and temper embrittlement. For applications projected for fusion machines at lower temperatures, a new heat treatment (1000/sup 0/C, 1 h, air-cooled followed by 650/sup 0/C tempering) at lower temperatures and shorter times than the vendor-recommended heat treatment has been identified. Microstructural differences between the treatments are discussed, and mechanical properties are correlated. 6 figures.
Effects of shot-peening residual stresses on the fracture and crack-growth properties of D6AC steel
NASA Technical Reports Server (NTRS)
Elber, W.
The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5 mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that shot-peening residual stresses influence the fracture and crack-growth properties of the material. This report presents the analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions.
The effects of shot-peening residual stresses on the fracture and crack growth properties of D6AC steel
NASA Technical Reports Server (NTRS)
Elber, W.
The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that the shot-peening residual stresses influence the fracture and crack-growth properties of the material. The analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions are presented.
Elevated-temperature tensile and creep properties of several ferritic stainless steels
NASA Technical Reports Server (NTRS)
Whittenberger, J. D.
The elevated-temperature mechanical properties of several ferritic stainless steels were determined. The alloys evaluated included Armco 18SR, GE 1541, and NASA-18T-A. Tensile and creep strength properties at 1073 and 1273 K and residual room temperature tensile properties after creep testing were measured. In addition, 1273 K tensile and creep tests and residual property testing were conducted with Armco 18SR and GE 1541 which were exposed for 200 hours to a severe oxidizing environment in automotive thermal reactors. Aside from the residual tensile properties for Armco 18SR, prior exposure did not affect the mechanical properties of either alloy. The 1273 K creep strength parallel to the sheet-rolling direction was similar for all three alloys. At 1073 K, NASA-18T-A had better creep strength than either Armco 18SR or GE 1541. NASA-18T-A possesses better residual properties after creep testing than either Armco 18SR or Ge 1541.
Development of domain refined grain-oriented silicon steel by grooving
NASA Astrophysics Data System (ADS)
Sato, K.; Honda, A.; Nakano, K.; Ishida, M.; Fukuda, B.; Kan, T.
Recently a heat-proof magnetic domain refining technique has been developed which is characterized by the introduction of grooves on a surface of steel sheet after final cold rolling. In this paper, magnetic properties and the domain refining effect of grooving are investigated. A grooving process is constituted by resist printing on the surface of steel sheets after final cold rolling and succeeding electrolytic etching. The grooves were introduced almost perpendicular to the rolling direction of steel sheets. The width and depth of each grove are about 200 and 20 ?m, respectively. With this newly developed method, about 10% reduction in iron loss was achieved and less than 0.34 W/lb at 1.5 T, 60 Hz was obtained. Using this new material, the iron loss of wound core transformers can be reduced by about 10% as compared with nongrooved material. Domain width was dramatically reduced by grooving, which caused the reduction of eddy current loss. This reduction is considered to be caused by the demagnetizing field effect due to free poles in the vicinity of grooves. It was clarified that in grooved sheets the magnetization on the ungrooved surfaces proceeded faster than on the grooved surfaces and therefore, hysteresis loss and magnetizing characteristics did not deteriorate by grooving.
A study of tailored blank welding between mild steel sheet and zn-coated steel sheet by CO 2 laser beam
Jong Hyun Suh; To Hoon Kim; Byung Kil Yu; Kyoung Don Lee
Research was conducted on tailored blank welding between mild steel sheet and Zn-coated steel sheet using CO2 laser beam. The materials used in this study were low carbon steel sheets with a thickness of 1.2 mm and Zn-coated steel\\u000a sheet with the same thickness and 6.3 ?m Zn coating. Experiments were conducted by applying the Taguchi method to obtain optimum
Effect of High-Velocity Oxy-Fuel (HVOF) Thermal Spraying on Physical and Mechanical Properties of Type 316 Stainless Steel
Terry C. Totemeier
Data on the microstructural, physical, and mechanical characteristics of high-velocity oxygen-fuel (HVOF)-sprayed type 316 stainless steel coatings are presented and compared with properties of wrought 316 stainless steel. Coatings were prepared at three different spray particle velocities; coating characteristics are presented as a function of velocity. The coatings had relatively low porosity and oxide contents and were significantly harder than annealed, wrought 316 stainless steel. The hardness difference is primarily attributed to high dislocation densities resulting from peening imparted by high-velocity spray particles. The coating hardness increased with increasing spray particle velocity, reflecting increased peening effects. The elastic modulus of the coatings was essentially identical to wrought material. The mean coefficient of thermal expansion of as-sprayed coatings was lower than wrought material, but the expansion of annealed coatings matched the wrought behavior.
Nondestructive Evaluation of Strain Distribution and Fatigue Distribution from Austenitic Stainless Steel by Using Magnetic Sensors
Tsuchida, Y.; Enokizono, M. [Department of Electrical and Electronic Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan); Oka, M.; Yakushiji, T. [Department of Computer and Control Engineering, Oita National College of Technology, 1666 Maki, Oita 870-0152 (Japan)
Austenitic stainless steel transforms from austenitic crystal structure to martensitic crystal structure after applying strain or stress. Because martensitic crystal structures have magnetization, strain evaluation and fatigue evaluation can be performed by measuring magnetic properties. This paper describes the measurement of leakage magnetic flux density of remanent magnetization for the strain evaluation and the fatigue evaluation by a typical Hall element sensor for SUS 304 and SUS 304L and by a high-sensitivity thin-film flux-gate magnetic sensor for SUS 316 and SUS 316L.
Effects of sulfur content and slab reheating temperature on the magnetic properties of fully processed nonoriented electrical steels
NASA Astrophysics Data System (ADS)
Hou, Chun-Kan
The effects of sulfur content and slab reheating temperature on the magnetic properties of four fully processed nonoriented electrical steels have been investigated. Four slabs of nonoriented electrical steels with sulfur content in the range of 0.0006-0.0126 wt% were reheated to 1100, 1200, and 1300 ░C, respectively. Then, they were hot rolled and annealed at 700 ░C, cold rolled at the same condition and annealed at 820 ░C in the salt bath furnace for 1 min to simulate continuous annealing. The ac core loss, dc hysteresis loss, and ac and dc permeability were measured at 15 kG inductions. It was found that the amount of inclusions in the hot-rolled bands increased with increasing slab reheating temperature and increasing sulfur content in steels. After final annealing, grain sizes of cold-rolled steel sheets decreased with increasing sulfur content and increasing slab reheating temperature. The main preferred orientations in the final annealed steel sheets were (0 1 1) <1 0 0> and (1 1 1) < u v w> ? fiber texture. Steel sheets containing 0.0032 and 0.0060 wt% sulfur developed a more stronger (0 1 1)<1 0 0> texture than other steel sheets. However, steel sheets containing 0.0126 wt% sulfur had the weakest (1 1 1)< u v w> texture during slab reheating at temperatures higher than 1200 ░C. Both ac core loss and dc hysteresis loss increased with increasing slab reheating temperature and increasing sulfur content in steel sheets. Both ac and dc permeability decreased with increasing slab reheating temperature and increasing sulfur content in steel sheets. If sulfur content decreased from 0.0060 to 0.0032 wt%, there were great improvements in ac core loss, dc hysteresis loss, and ac and dc permeability. However, eddy current loss was almost independent of the sulfur content and slab reheating temperature.
Charpy toughness and tensile properties of a neutron-irradiated stainless steel submerged arc weld cladding overlay
W. R. Corwin; R. G. Berggren; R. K. Nanstad
The cladding was applied to a pressure vessel steel plate by the submerged arc, single-wire, oscillating-electrode method. Three layers of cladding provided a thickness adequate for fabrication of test specimens. The first layer was type 309, and the upper two layers were type 308 stainless steel. The type 309 was diluted considerably by excessive melting of the base plate. Specimens
Study by EELS of helium bubbles in a martensitic steel
NASA Astrophysics Data System (ADS)
Frķchard, S.; Walls, M.; Kociak, M.; Chevalier, J. P.; Henry, J.; Gorse, D.
This work presents measurements of the helium density and pressure in small bubbles in a martensitic steel, which is a vital first step towards identifying their role in the microstructural mechanisms determining the macroscopic properties of the material. Electron Energy-Loss Spectroscopy in the Scanning Transmission Electron Microscope has been used to analyse individual bubbles. The energy shift of the 1s ? 2p transition and the helium density have been measured for each bubble analysed. The pressure inside the bubbles has been calculated from the helium density using an equation of state. In these bubbles, the values for the helium pressure seem to be smaller than the equilibrium pressure, and agree in trend with the findings of previous studies, although our results extend to smaller radii and higher pressures.
Tritium and decay helium effects on the fracture toughness properties of types 316L, 304L and 21Cr-6Ni-9Mn stainless steels
Morgan, M.J.; Tosten, M.H
J-integral fracture mechanics techniques and electron microscopy observations were used to investigate the effects of tritium and its radioactive decay product, {sup 3}He, on Types 316L, 304L and 21Cr-6Ni-9Mn stainless steels. Tritium-exposed-and-aged steels had lower fracture-toughness values and shallower sloped crack-growth-resistance curves than unexposed steels. Both fracture-toughness parameters decreased with increasing concentrations of {sup 3}He. The fracture-toughness reductions were accompanied by a change in fracture mode from microvoid-nucleation-and-growth processes in control samples to grain-and-twin-boundary fracture in tritium-charged-and-aged samples. Type 316L stainless steel had the highest fracture-toughness values and Type 21Cr-6Ni-9Mn had the lowest. Samples containing {sup 3}He but degassed of tritium had fracture toughness properties that were similar to uncharged samples. The results indicate that helium bubbles enhance the embrittlement effects of hydrogen by affecting the deformation properties and by increasing localized hydrogen concentrations through trapping effects.
Microstructures and Mechanical Properties of a New As-Hot-Rolled High-Strength DP Steel Subjected to Different Cooling Schedules
NASA Astrophysics Data System (ADS)
Hu, Jun; Du, Lin-Xiu; Wang, Jian-Jun; Gao, Cai-Ru; Yang, Tong-Zi; Wang, An-Yang; Misra, R. D. K.
Controlled rolling followed by accelerated cooling was carried out in-house to study the microstructure and mechanical properties of a low carbon dual-phase steel. The objective of the study described here was to explore the effect of cooling schedule, such as air cooling temperature and coiling temperature, on the final microstructure and mechanical properties of dual-phase steels. Furthermore, the precipitation behavior and yield ratio are discussed. The study demonstrates that it is possible to obtain tensile strength and elongation of 780 MPa and 22 pct, respectively, at the two cooling schedules investigated. The microstructure consists of 90 pct ferrite and 10 pct martensite when subjected to moderate air cooling and low temperature coiling, such that the yield ratio is a low 0.69. The microstructure consists of 75 pct ferrite and 25 pct granular bainite with a high yield ratio of 0.84 when the steel is directly cooled to the coiling temperature. Compared to the conventional dual-phase steels, the high yield strength is attributed to precipitation hardening induced by nanoscale TiC particles and solid solution strengthening by high Si content. The interphase precipitates form at a suitable ledge mobility, and the row spacing changes with the rate of ferrite transformation. There are different orientations of the rows in the same grain because of the different growth directions of the ferrite grain boundaries, and the interface of the two colonies is devoid of precipitates because of the competitive mechanisms of the two orientations.
Study of the Effects of High Temperatures on the Engineering Properties of Steel 42CrMo4
NASA Astrophysics Data System (ADS)
Brnic, Josip; Turkalj, Goran; Canadija, Marko; Lanc, Domagoj; Brcic, Marino
The paper presents and analyzes the experimental results of the effect of elevated temperatures on the engineering properties of steel 42CrMo4. Experimental data relating to the mechanical properties of the material, the creep resistance as well as Charpy impact energy. Temperature dependence of the mentioned properties is also shown. Some of creep curves were simulated using rheological models and an analytical equation. Finally, an assessment of fracture toughness was made that was based on experimentally determined Charpy impact energy. Based on the obtained results it is visible that the tensile strength (617 MPa) and yield strength (415 MPa) have the highest value at the room temperature while at the temperature of 700 ░C (973 K) these values significantly decrease. This steel can be considered resistant to creep at 400 ░C (673 K), but at higher temperatures this steel can be subjected to low levels of stress in a shorter time.
Low temperature mechanical properties, fractographic and metallographic evaluation of several alloy steels
NASA Technical Reports Server (NTRS)
Montano, J. W.
The mechanical properties are presented of alloy steels, 4130, 4140, 4340, 6150, and 8740. Test specimens were manufactured from approximately 1.00 inch (2.54 cm) diameter bar stock which had been heat treated to two different hardness levels. The following mechanical tests were performed at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C): (1) tensile test (Ultimate, yield, modulus, elongation, and reduction of area), (2) notched tensile test, (3) charpy V-notched impact test (impact energy), and (4) double shear strength test (ultimate and yield). The test data indicate excellent tensile strength, notched/unnotched tensile ratios, ductility, impact, and shear properties at all test temperatures, except at -200 F (-129 C) where the impact strength of the higher strength group of alloy steels, 4130 (Rc-37) and 4140 (Rc-44) decreased to approximately 9 ft. lbs. (12 joules) and 6 ft. lbs. (8 joules), respectively. Chemical, metallographic, and fractographic analyses were also performed to evaluate microstructure, microhardness and the effect of decrease in temperature on the ductile to brittle failure transition.
Influence of silicon on the microstructures, mechanical properties and stretch-flangeability of dual phase steels
NASA Astrophysics Data System (ADS)
Zhou, Le-yu; Zhang, Dan; Liu, Ya-zheng
Uniaxial tension tests and hole-expansion tests were carried out to determine the influence of silicon on the microstructures, mechanical properties, and stretch-flangeability of conventional dual-phase steels. Compared to 0.03wt% silicon, the addition of 1.08wt% silicon induced the formation of finer ferrite grains (6.8 ?m) and a higher carbon content of martensite ( C m ? 0.32wt%). As the silicon level increased, the initial strain-hardening rate ( n value) and the uniform elongation increased, whereas the yield strength, yield ratio, and stretch-flangeability decreased. The microstructures were observed after hole-expansion tests. The results showed that low carbon content martensite ( C m ? 0.19wt%) can easily deform in coordination with ferrite. The relationship between the mechanical properties and stretch-flangeability indicated that the steel with large post-uniform elongation has good stretch-flangeability due to a closer plastic incompatibility of the ferrite and martensite phases, which can effectively delay the production and decohesion of microvoids.
Effect of surface nanocrystallization on abrasive wear properties in Hadfield steel
Weilin Yan; Liang Fang; Zhanguang Zheng; Kun Sun; Yunhua Xu
A nanocrystalline surface layer was synthesized on a Hadfield steel by shot peening treatment. The microstructure evolvement of the surface layer of the shot peening treated sample was characterized by optical microscopy, X-ray diffraction and high-resolution transmission electron microscopy. It has been shown that the grain sizes in surface layer were decreased to 11.1¢17.4nm after 60min shot peening duration. Surface
A mechanical property and stress corrosion evaluation of 431 stainless steel alloy
NASA Technical Reports Server (NTRS)
Montano, J. W.
The mechanical properties of type 431 stainless steel in two conditions: annealed bar and hardened and tempered bar are presented. Test specimens, manufactured from approximately 1.0 inch (2.54 cm) diameter bar stock, were tested at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C). The test data indicated excellent tensile strength, notched/unnotched tensile ratio, ductility, shear, and impact properties at all testing temperatures. Results of the alternate immersion stress corrosion tests on stressed and unstressed longitudinal tensile specimens 0.1250 inch (0.3175 cm) diameter and transverse C-ring specimens, machined from 1.0 inch (2.54 cm) diameter bar stock, indicated that the material is not susceptible to stress corrosion cracking when tested in a 3.5 percent NaCl solution for 180 days.
Relationship between ultrasonic characteristics and mechanical properties of tempered martensitic stainless steel
NASA Astrophysics Data System (ADS)
Hsu, Cheng-Hsun; Teng, Hwei-Yuan; Chen, Yeong-Jern
This research studied the relationship between the ultrasonic characteristics and the mechanical properties of tempered CA-15 martensitic stainless steel (MSS). The results show that, for as-quenched specimens, a chromium carbide film at the martensitic boundary of the as-cast specimen will disappear causing a change in the mechanical properties (e.g., the tensile strength is decreased or the hardness and the toughness are increased). For the tempered MSS, the correlation of the ultrasonic velocity and the tensile strength, hardness, and toughness is not obvious. However, there is a highly positive correlation with the elastic modulus (E) of the material. For the ultrasonic attenuation evaluation, the attenuation coefficient (?) has a positive correlation with the tensile strength and the hardness, while there is a negative correlation with the toughness and the elongation. Also, a higher-frequency probe would cause the better sensitivity, but the data are relatively dispersed.
Structural, mechanical and tribological properties of duplex-treated AISI 5140 steel
Alsaran, Akguen [Department of Mechanical Engineering, Ataturk University, 25240, Erzurum (Turkey)]. E-mail: email@example.com; Celik, Ayhan [Department of Mechanical Engineering, Ataturk University, 25240, Erzurum (Turkey); Karakan, Mehmet [Department of Mechanical Engineering, Ataturk University, 25240, Erzurum (Turkey)
The structure, hardness, adhesion, surface roughness and tribological properties of duplex-surface-treated (TiN/plasma nitrided), directly TiN-coated and ion-nitrided AISI 5140 steel were investigated using X-ray diffraction, SEM, optical microscopy, a microhardness tester, a scratch tester and a pin-on-disc tribotester. After the plasma nitriding process, the transition treatments were realized to evaluate the effect of the compound layer. It was found that the relative intensity line of TiN (200) and surface roughness increased, but the coating hardness and critical load (Lc) decreased with an increasing amount of {epsilon}-Fe{sub 2-3}N iron nitride in the compound layer. The better tribological properties were obtained with coatings applied on substrates, which included a large amount of {gamma}'-Fe{sub 4}N iron nitride after plasma nitriding.
Microstructure and Properties of Selective Laser Melted High Hardness Tool Steel
NASA Astrophysics Data System (ADS)
Feuerhahn, F.; Schulz, A.; Seefeld, T.; Vollertsen, F.
A secondary hardening tool steel material X110CrMoVAl 8-2 was successfully processed by selective laser melting (SLM), producing defect free samples of high density. The microstructure appeared irregular after SLM, which was attributed to locally different temper states in consequence of the SLM process pattern. By a subsequent heat treatment, a homogeneous microstructure with ultrafine carbide precipitations and a very high resulting hardness of 765 HV were achieved. The hardness came very close to that of the same material processed by spray forming and forging, whilst the SLM microstructure was significantly finer. Therefore this tool steel material was considered as highly promising for SLM manufacturing of tools, e.g. for micro tooling applications.
Surface modification of medium carbon steel by electron beam alloying
NASA Astrophysics Data System (ADS)
Yonekura, Daisuke; Iida, Kohei
An electron beam surface alloying was applied to a medium carbon steel disk using hBN, W and WC powders in order to examine the effect of these powder materials on the microstructure and hardness. The study reveals that, the surface hardness was improved by the electron beam irradiation with all powders and no surface cracks were observed due to the martensitic transformation and the surface alloying. However the influence of powder materials on the hardness was little. Thus, it was found the surface modification by the electron beam irradiation with various powders is effective way to improve the surface hardness as well as the prevention of surface cracking.
Effect of different salts on the corrosion properties of friction type A607 steel rock bolt in simulated concentrated water
Suresh Divi; Dhanesh Chandra; Jaak Daemen
Friction type steel rock bolts are one of the most commonly used for reinforcing tunnels (since the late 1970s) due to their ability to sustain large rock mass displacements. In this paper, corrosion behavior of an FRS rock bolt (ASTM A607 steel) was investigated under Yucca Mountain simulated concentrated water at different concentrations (1ū, 10ū and 100ū) and temperatures by
Effect of heat treatment and neutron irradiation on magnetic properties of ferritic-martensitic steels containing 12% Cr
NASA Astrophysics Data System (ADS)
Chukalkin, Yu. G.; Goshchitskii, B. N.; Leont'eva-Smirnova, M. V.; Chernov, V. M.
The magnetic properties (magnetization, coercive force) of ferritic-martensitic steels EK-181 (low-activation, Fe-12Cr-2W-V-Ta) and ChS-139 (Fe-12Cr-2W-V-Ta-Mo-Nb-Ni) have been studied. The steel samples were subjected to different heat treatments and irradiation with neutron fluences of up to 5 ū 1019 cm-2 ( E n ? 0.1 MeV) in an IVV-2M nuclear reactor at a temperature no higher than 70░C. Within the limits of the experimental error (ś1%), the heat treatment and neutron irradiation have almost no effect on the magnitude of the magnetization of these steels. Neutron irradiation leads to an increase in the coercive force of steels up to ś50% depending on the regimes of heat treatment and neutron fluence.
Lubrication of Steel\\/Steel Contacts by Choline Chloride Ionic Liquids
S. D. A. Lawes; S. V. Hainsworth; P. Blake; K. S. Ryder; A. P. Abbott
There is a growing interest in the use of ionic liquids to provide lubrication for challenging contacts. This study is an\\u000a initial assessment of the application of two ionic liquids based on choline chloride cations to be used as ionic liquid lubricants\\u000a for engineering contacts, in this case steel on steel. These ionic liquids, termed ethaline and reline, have anions
Comparison of Microstructure and Surface Properties of AISI 1045 Steel After Quenching in Hot Alkaline Salt Bath and Oil
NASA Astrophysics Data System (ADS)
Raygan, S.; Rassizadehghani, J.; Askari, M.
The effect of quenching in molten alkaline salt bath medium on the microstructure and surface properties of AISI 1045 steel in comparison with oil was investigated. Salt bath medium used in this research contained 40% NaOH and 60% KOH with addition of 5 wt.% water at 205 ░C. Hardening of 1045 steel in this medium resulted in an almost uniform microstructure, which consisted of fine martensite and bainite. In comparison, the microstructure of oil quenched sample was martensite, ferrite, widmanestatten ferrite, and pearlite. Quenching in salt bath lead to improved surface properties, i.e., decrease in surface roughness and a good bearing area curve.
Precipitation Behavior and Mechanical Properties of Ti-Mo Medium-Carbon Steel During Austenite to Bainite Transformation
NASA Astrophysics Data System (ADS)
Deng, Xiangtao; Wang, Zhaodong; Misra, R. D. K.; Han, Jie; Wang, Guodong
The precipitation behavior and evolution of mechanical properties of Ti-Mo-bearing microalloyed medium-carbon steel during austenite to bainite transformation were studied, and two different cooling rates including ultrafast cooling (~80 ░C/s) and accelerated cooling (~15 ░C/s) during transformation were also investigated. The results suggest that Ti-Mo-bearing medium-carbon steel yield finer microstructure and nano-precipitates during austenite to bainite transformation during both ultrafast cooling and accelerated cooling processes. Yield strength and tensile strength obtained by ultrafast cooling process were higher than the accelerated cooling process, while the elongation was slightly reduced. Microstructural characterization indicated that grain refinement and precipitation hardening were the primary reasons for the increase in strength. Ultrafast cooling increased the density of dislocations and refined the grain size. Average size of precipitates containing Ti and Mo was 3-6 nm by ultrafast cooling process, while average precipitate size obtained by accelerated cooling process was 6-9 nm.
Utilization of steel, pulp and paper industry solid residues in forest soil amendment: relevant physicochemical properties and heavy metal availability.
Mõkelõ, Mikko; Watkins, Gary; P÷yki÷, Risto; Nurmesniemi, Hannu; Dahl, Olli
Industrial residue application to soil was investigated by integrating granulated blast furnace or converter steel slag with residues from the pulp and paper industry in various formulations. Specimen analysis included relevant physicochemical properties, total element concentrations (HCl+HNO3 digestion, USEPA 3051) and chemical speciation of chosen heavy metals (CH3COOH, NH2OHĘHCl and H2O2+H2O2+CH3COONH4, the BCR method). Produced matrices showed liming effects comparable to commercial ground limestone and included significant quantities of soluble vital nutrients. The use of converter steel slag, however, led to significant increases in the total concentrations of Cr and V. Subsequently, total Cr was attested to occur as Cr(III) by Na2CO3+NaOH digestion followed by IC UV/VIS-PCR (USEPA 3060A). Additionally, 80.6% of the total concentration of Cr (370 mg kg(-1), d.w.) occurred in the residual fraction. However, 46.0% of the total concentration of V (2470 mg kg(-1), d.w.) occurred in the easily reduced fraction indicating potential bioavailability. PMID:21377785
Surface mechanical properties of S30432 austenitic steel after shot peening
NASA Astrophysics Data System (ADS)
Zhan, K.; Jiang, C. H.; Ji, V.
The surface yield strength of S30432 austenitic steel after conventional and dual shot peening treatments has been investigated by means of X-ray stress analysis. The results showed that the proof stress ?0.2 of the shot peened surface increased to around 830 MPa and 940 MPa after conventional and dual shot peening, respectively. While for the bulk S30432 austenitic steel, the yield strength was 268 MPa. The strengthen mechanism was discussed in terms of microstructure by X-ray line profile analysis method. The results revealed that the refined domain size and high micro-strain were induced in the deformed surface layer. This changed microstructure was mainly responsible for the high yield strength of shot peened surface. The surface yield strength of the material surface can be obtained from the proposed X-ray stress analysis method. Therefore, this method can be considered as a complementary approach in investigating the microstructural hardening effect of SP treatment.
Study of passive films formed on AISI 304 stainless steel by impedance measurements and photoelectrochemistry
Simoes, A.M.P.; Ferreiro, M.G.S. (Dept. de Engenharia Quimica, Instituto Superior Tecnico, 1096 Lisboa Codex (PT)); Rondot, B.; Belo, M. (Centre National de la Recherche Scientifique, 94 - Vitry-sur-Seine (France). Centre d'Etudes de Chimie Metallurgique)
Moss-Schottky plots and photoelectrochemical measurements were made on films formed at different potentials on AISI 304 stainless steel in a borate/boric acid solution, pH 9.2. The results allowed the determination of the semiconductive properties and band structure of the films, which account for the existence of two kinds of films depending on the formation potential. For potentials below 0 V (SCE), the results point out for a film with an inverse spinel structure constituted by Cr-substituted magnetite with two donor levels. Above 0 V only one donor level is detected, which should be Fe{sup 2 +} on tetrahedral sites.
Electrochemical properties and corrosion protection of stainless steel for hot water tank
Seong-Jong Kim; Seok-Ki Jang; Jeong-Il Kim
The state in which a stainless steel (STS) exhibits a very low corrosion rate is known as passivity, which is self-healing\\u000a in a wide variety of environments. However, for those STS the corrosion includes pitting, crevice corrosion, galvanic corrosion,\\u000a hydrogen embrittlement and stress corrosion cracking etc. And the corrosion resistance of STS is affected by area ratio, solution\\u000a temperature and
Characteristics and cementitious properties of ladle slag fines from steel production
Caijun Shi
Ladle slag is a by-product from further refining molten steel after coming out of a basic oxygen furnace (BOF) or an electric arc furnace (EAF). Air-cooled ladle slag has a very large portion of fine particles due to the conversion of ?-C2S to ?-C2S during the cooling process. X-ray diffraction (XRD) analysis of three ladle slag fine samples passing 100,
Radiation effects on low cycle fatigue properties of reduced activation ferritic\\/martensitic steels
T. Hirose; H. Tanigawa; M. Ando; A. Kohyama; Y. Katoh; M. Narui
The reduced activation ferritic\\/martensitic steel, RAFs F82H IEA heat has been fatigue-tested at ambient temperature under diametral strain controlled conditions. In order to evaluate the effects of radiation damage and transmutation damage on fatigue characteristics, post-neutron irradiation and post-helium ion implantation fatigue tests were carried out. Fracture surfaces and fatigue crack initiation on the specimen surface were observed by SEM.
Effect of microfissures on corrosion performance and mechanical properties of austenitic stainless steel weld metals
Yan Cui
It is generally recognized that hot cracking or microfissuring is one of the main concerns in austenitic stainless steel welding. In this study, eight kinds of commercial and modified electrodes provided by Lincoln Electric Company, ESAB and Hobart were used to produce fissure-containing and fissure-free welded coupons for extracting the samples for this investigation. The modified electrodes, E308L, E316L, E308H
Influence of thermo-mechanical treatment on the tensile properties of a modified 14Cr-15Ni stainless steel
NASA Astrophysics Data System (ADS)
Vijayanand, V. D.; Laha, K.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Mathew, M. D.
The titanium modified 14Cr-15Ni austenitic stainless steel is used as clad and wrapper material for fast breeder nuclear reactor. Thermo-mechanical treatments consisting of solution annealing at two different temperatures of 1273 and 1373 K followed by cold-work and thermal ageing have been imparted to the steel to tailor its microstructure for enhancing strength. Tensile tests have been carried out on the thermo-mechanically treated steel at nominal strain rate of 1.6 ū 10-4 s-1 over a temperature range of 298-1073 K. The yield stress and the ultimate tensile strength of the steel increased with increase in solution treatment temperature and this has been attributed to the fine and higher density of Ti(C,N) precipitate. Tensile flow behaviour of the steel has been analysed using Ludwigson and Voce constitutive equations. The steel heat treated at higher solution temperature exhibited earlier onset of cross slip during tensile deformation. The rate of recovery at higher test temperatures was also influenced by variations in solution heat treatment temperature. In addition, dynamic recrystallization during tensile deformation at higher temperatures was profound for steel solution heat-treated at lower temperature. The differences in flow behaviour and softening mechanisms during tensile testing of the steel after different heat treated conditions have been attributed to the nature of Ti(C,N) precipitation.
Microstructure and mechanical property of ferritic-martensitic steel cladding under a 650 ░C liquid sodium environment
NASA Astrophysics Data System (ADS)
Kim, Jun Hwan; Kim, Sung Ho
A study was carried out to investigate the effect of liquid sodium on the microstructural and mechanical property of ferritic-martensitic steel (FMS) used for a Sodium-cooled Fast Reactor (SFR) cladding tube. A quasi-dynamic device characterized by natural circulation was constructed and a compatibility test between FMS and liquid sodium was performed. HT9 (12Cr-1MoWVN) and Gr.92 (9Cr-2WNbVNB) coupons as well as a Gr.92 cladding tube were immersed in the 650 ░C liquid sodium up to 3095 h and a microstructural observation, a mechanical property evaluation such as nanoindentation, and a ring tension test were also done in this study. The results showed that both HT9 and Gr.92 exhibited macroscopic weight loss behavior where pitting and decarburization took place. Weight loss as well as the decarburization process decreased as the chromium content increased. A compatibility test over the cladding tube revealed that a decrease of the mechanical property caused by the aging process governed the whole mechanical property of the cladding tube.
Optical properties of ion beam textured metals. [using copper, silicon, aluminum, titanium and stainless steels
NASA Technical Reports Server (NTRS)
Hudson, W. R.; Weigand, A. J.; Mirtich, M. J.
Copper, silicon, aluminum, titanium and 316 stainless steel were textured by 1000 eV xenon ions from an 8 cm diameter electron bombardment ion source. Simultaneously sputter-deposited tantalum was used to facilitate the development of the surface microstructure. Scanning electron microscopy of the ion textured surfaces revealed two types of microstructure. Copper, silicon, and aluminum developed a cone structure with an average peak-to-peak distance ranging from 1 micron for silicon to 6 microns for aluminum. Titanium and 316 stainless steel developed a serpentine ridge structure. The average peak-to-peak distance for both of these materials was 0.5 micron. Spectral reflectance was measured using an integrating sphere and a holraum reflectometer. Total reflectance for air mass 0 and 2, solar absorptance and total emittance normalized for a 425 K black body were calculated from the reflectance measurements.
Effect of long-term service on the tensile properties and capability of pipeline steel 17GS to resist cleavage fracture
S. O. Kotrechko; A. Ya. Krasowsky; Yu. Ya. Meshkov; V. M. Torop
A transit oil pipeline of diameter 720 mm and 334 km in length of steel 17GS after 30 years of service was twice non-destructively tested using intelligent pigs. Two segments of this pipeline were cut in order to investigate the steel structure, composition, and mechanical properties and to compare these properties with those of the archive material. Metallographic and microprobe
Soft magnetic composites manufactured by warm co-extrusion of bulk metallic glass and steel powders
NASA Astrophysics Data System (ADS)
Johnson, Francis; Raber, Thomas R.; Zabala, Robert J.; Buresh, Steve J.; Tanico, Brian
Soft magnetic composites of Fe-based bulk metallic glass and low-alloy steel have been manufactured by warm co-extrusion of precursor powders at temperatures within the supercooled liquid region of the glass. Composites were manufactured with amorphous volume fractions of 75%, 67%, and 100%. Full consolidation of the constituent powders was observed with the bulk metallic glass remaining substantially amorphous. The composite electrical resistivity was observed to be anisotropic with a resistivity of 79 ?? cm measured transverse to the extrusion axis in a sample with 75% amorphous volume fraction. A 0-3 connectivity pattern with the low-resistivity steel phase embedded in a 3-dimensionally connected high-resistivity bulk metallic glass phase was observed with scanning electron microscopy. This confirms that the flow characteristics of the bulk metallic glass and the steel powders were comparable during extrusion at these temperatures. The saturation magnetization of 1.3 T was consistent with the volume weighted average of the saturation magnetization of the two phases. A relatively high quasistatic coercivity of 8 Oe was measured and is likely due to slight crystallization of the bulk metallic glass as well as domain wall pinning at prior particle boundaries. Careful control of the thermal environment during the extrusion process is required to minimize glass crystallization and achieve the desired balance of magnetic and electrical properties.
Reactor Materials Program - Baseline Material Property Handbook - Mechanical Properties of 1950's Vintage Stainless Steel Weldment Components, Task Number 89-23-A-1
Stoner, K.J.
The Process Water System (primary coolant) piping of the nuclear production reactors constructed in the 1950''s at Savannah River Site is comprised primarily of Type 304 stainless steel with Type 308 stainless steel weld filler. A program to measure the mechanical properties of archival PWS piping and weld materials (having approximately six years of service at temperatures between 25 and 100 degrees C) has been completed. The results from the mechanical testing has been synthesized to provide a mechanical properties database for structural analyses of the SRS piping.
The dependence of crack properties on the Cr\\/Ni equivalent ratio in AISI 304L austenitic stainless steel weld metals
D. J. Lee; J. C. Byun; J. H. Sung; H. W. Lee
The crack properties and mechanical characteristics in AISI 304L stainless steel weld metals were evaluated by differentiating solidification mode using three newly designed filler wires with flux-cored arc welding (FCAW) process. Microstructure examination showed that the delta ferrite content in the deposited metals increased with an increasing equivalent ratio of chromium\\/nickel. Solidification cracking was observed in the first layer of
Analysis of the effect of shot peening on mechanical properties of steel sheets used as screener sieve materials
NASA Astrophysics Data System (ADS)
?led?, M.; Bak, ?.; Stachowicz, F.; Zielecki, W.
Numerous studies have been performed in an attempt to improve fatigue strength of materials by creating compressive residual stresses in the surface layers as a result of the shot peening process. It was shown that the process is highly effective when dealing with particular parts of the body (detail) needed special attention. In this case, those are parts of screen sieve plate situated near the fixed edge and undergo the largest deformation caused by impact bending and thus need a special treatment. In this paper, the results of experimental tests are presented to analyse the effect of microshot peening on mechanical properties, surface layer characteristics and fatigue strength of steel sheet specimens. The data obtained from our experiments can be used for numerical simulations to design details with improved fatigue resistance.
Metallurgical properties of reduced activation martensitic steel Eurofer'97 in the as-received condition and after thermal ageing
NASA Astrophysics Data System (ADS)
Fernßndez, P.; Lancha, A. M.; Lape±a, J.; Serrano, M.; Hernßndez-Mayoral, M.
This paper describes the microstructural studies and the mechanical testing (hardness, tensile and charpy tests) performed on the Eurofer'97 steel in the as-received condition and after thermal ageing treatments up to 600 ░C. In addition, fracture toughness tests on the as-received condition have been carried out in order to determine the Master Curve. During the thermal ageing treatments studied (500 ░C/5000 h and 600 ░C/1000 h) the general microstructure of the steel (tempered martensite with M 23C 6 and MX precipitates) remained stable. Only a slight growth of the particles has been observed. In terms of mechanical properties, the Eurofer'97 steel exhibited similar values of tensile properties (tensile and yield strength) and ductile-brittle transition temperature regardless of the material condition studied.
Data collection on the effect of irradiation on the mechanical properties of austenitic stainless steels and weld metals
Tavassoli, A.A. [Commissariat a l`Energie Atomique, Gif sur Yvette (France); Picker, C.; Wareing, J. [AEA Technology, Risley (United Kingdom)
Data on the influence of low dose 400--550 C irradiation on the mechanical properties of structural steels (Types 304, 316, 316L, 316H and 316L(N) and associated weld metals) at temperatures from 20 C to 750 C, have been compiled from published literature and the results of British, Dutch, French and German laboratories. Properties evaluated include tensile, impact, creep, fatigue, and creep-fatigue. The preliminary results, which cover the dose range from 0 to 5 displacements per atom (and/or up to 9 appm helium) are presented as comparisons between irradiated and unirradiated control data, covering a range of strength and cyclic properties. The results show that low dose irradiation can have a significant influence on the properties, i.e.: (1) increases in tensile proof strength; (2) reductions in tensile ductility; (3) decreases in impact energy; (4) reductions in creep-rupture strength and ductility; and (5) reductions in creep-fatigue endurance. By considering the influence of irradiation temperature and dose level, the results are rationalized in terms of irradiation hardening and grain boundary embrittlement mechanisms.
The Relationship Between Microstructural Evolution and Mechanical Properties of Heavy Plate of Low-Mn Steel During Ultra Fast Cooling
NASA Astrophysics Data System (ADS)
Wang, Bin; Wang, Zhao-dong; Wang, Bing-xing; Wang, Guo-dong; Misra, R. D. K.
We describe here the electron microscopy and mechanical property studies that were conducted in an industrially processed 20- and 40-mm C-Mn thick plates that involved a new approach of ultrafast cooling (UFC) together with significant reduction in Mn-content of the steel by ~0.3 to 0.5 pct, in relation to the conventional C-Mn steels, with the aim of cost-effectiveness. The study demonstrated that nanoscale cementite precipitation occurred during austenite transformation in the matrix of heavy plate during UFC, providing significant precipitation strengthening. With decrease in UFC stop temperature and consequent increase in the degree of undercooling, there was a transition in the morphology of cementite from lamellar to irregular-shaped nanoscale particles in the 20 mm heavy plate. With the increase in plate thickness, nanoscale cementite precipitated in bainitic lath at the surface of 40 mm heavy plate, which significantly increased the strength and decreased the elongation. Simultaneously, microstructural evolution in hot-rolled sheets was studied via simulation experiments using laboratory rolling mill to define the limits of microstructural evolution that can obtained in the UFC process and develop an understanding of the evolved microstructure in terms of process parameters.
Influence of Cold-Sprayed, Warm-Sprayed, and Plasma-Sprayed Layers Deposition on Fatigue Properties of Steel Specimens
NASA Astrophysics Data System (ADS)
Cizek, J.; Matejkova, M.; Dlouhy, I.; Siska, F.; Kay, C. M.; Karthikeyan, J.; Kuroda, S.; Kovarik, O.; Siegl, J.; Loke, K.; Khor, Khiam Aik
Titanium powder was deposited onto steel specimens using four thermal spray technologies: plasma spray, low-pressure cold spray, portable cold spray, and warm spray. The specimens were then subjected to strain-controlled cyclic bending test in a dedicated in-house built device. The crack propagation was monitored by observing the changes in the resonance frequency of the samples. For each series, the number of cycles corresponding to a pre-defined specimen cross-section damage was used as a performance indicator. It was found that the grit-blasting procedure did not alter the fatigue properties of the steel specimens (1% increase as compared to as-received set), while the deposition of coatings via all four thermal spray technologies significantly increased the measured fatigue lives. The three high-velocity technologies led to an increase of relative lives to 234% (low-pressure cold spray), 210% (portable cold spray), and 355% (warm spray) and the deposition using plasma spray led to an increase of relative lives to 303%. The observed increase of high-velocity technologies (cold and warm spray) could be attributed to a combination of homogeneous fatigue-resistant coatings and induction of peening stresses into the substrates via the impingement of the high-kinetic energy particles. Given the intrinsic character of the plasma jet (low-velocity impact of semi/molten particles) and the mostly ceramic character of the coating (oxides, nitrides), a hypothesis based on non-linear coatings behavior is provided in the paper.
The Relationship Between Microstructural Evolution and Mechanical Properties of Heavy Plate of Low-Mn Steel During Ultra Fast Cooling
NASA Astrophysics Data System (ADS)
Wang, Bin; Wang, Zhao-dong; Wang, Bing-xing; Wang, Guo-dong; Misra, R. D. K.
We describe here the electron microscopy and mechanical property studies that were conducted in an industrially processed 20- and 40-mm C-Mn thick plates that involved a new approach of ultrafast cooling (UFC) together with significant reduction in Mn-content of the steel by ~0.3 to 0.5 pct, in relation to the conventional C-Mn steels, with the aim of cost-effectiveness. The study demonstrated that nanoscale cementite precipitation occurred during austenite transformation in the matrix of heavy plate during UFC, providing significant precipitation strengthening. With decrease in UFC stop temperature and consequent increase in the degree of undercooling, there was a transition in the morphology of cementite from lamellar to irregular-shaped nanoscale particles in the 20 mm heavy plate. With the increase in plate thickness, nanoscale cementite precipitated in bainitic lath at the surface of 40 mm heavy plate, which significantly increased the strength and decreased the elongation. Simultaneously, microstructural evolution in hot-rolled sheets was studied via simulation experiments using laboratory rolling mill to define the limits of microstructural evolution that can obtained in the UFC process and develop an understanding of the evolved microstructure in terms of process parameters.
Microstructural Features Controlling Mechanical Properties in Nb-Mo Microalloyed Steels. Part I: Yield Strength
NASA Astrophysics Data System (ADS)
Isasti, Nerea; Jorge-Badiola, Denis; Taheri, Mitra L.; Uranga, Pello
Low carbon Nb-Mo microalloyed steels show interesting synergies between the "micro"-alloying elements when high strength-high toughness properties are required. Strain accumulation in austenite is enhanced, and therefore grain sizes are refined in the final microstructures. The presence of Mo facilitates the presence of non-polygonal phases, and this constituent modification induces an increment in strength through a substructure formation as well as through an increase in the dislocation density. Regarding fine precipitation and its strengthening effect, the mean size of NbC is reduced in the presence of Mo and their fraction increased, thus enhancing their contribution to yield strength. In this paper, a detailed characterization of the microstructural features of a series of microalloyed steels is described using the electron-backscattered diffraction technique. Mean crystallographic unit sizes, a grain boundary misorientation analysis, and dislocation density measurements are performed. Transmission electron microscopy is carried out to analyze the chemical composition of the precipitates and to estimate their volume fraction. In this first part, the contribution of different strengthening mechanisms to yield strength is evaluated and the calculated value is compared to tensile test results for different coiling temperatures and compositions.
Mechanical Properties of Reinforcing Steel and Fatigue Behavior in Corrosive Environment
NASA Astrophysics Data System (ADS)
Apostolopoulos, Ch. Alk.; Michalopoulos, D.
Corrosion of reinforcing steel has a great impact on the mass reduction and high- and low-cycle fatigue. An experimental study showed that the mass loss, the fatigue limit and the life expectancy were reduced by approximately 1.50-3.00%, 20-40%, and 55-75%, respectively, according to the level of corrosion. Low-cycle strain controlled fatigue testing under ▒1% and ▒2.5% constant amplitude strain, indicated that the corroded steel bars exhibit gradual reduction in available energy, number of cycles to failure and the load-bearing ability. Formation of pits and notches took place on the corroded steel surface and stress concentration points were developed which are highly localized at imperfections and especially at the rib bases. The fatigue limit was reduced considerably since the existence of ribs and the formation of pits and notches combined with the mass loss led to reduction of the exterior hard layer of martensite and drastic drop in the energy density of the corroded specimens. Antiseismic design that does not take into account the maximum and cumulative plastic deformation demands and the strain history that a structure will suffer under severe ground motion could lead to unpredictable performance.
Seismic Rehabilitation of RC Frames by Using Steel Panels
Mowrtage, Waiel [Kandilli Observatory and Earthquake Research Institute of Bogazici University, Earthquake Engineering Department, Istanbul (Turkey)
Every major earthquake in Turkey causes a large number of building suffer moderate damage due to poor construction. If a proper and fast retrofit is not applied, the aftershocks, which may sometimes come days or weeks after the main shock, can push a moderately damaged building into a major damage or even total collapse. This paper presents a practical retrofit method for moderately damaged buildings, which increases the seismic performance of the structural system by reducing the displacement demand. Fabricated steel panels are used for the retrofit. They are light-weight, easy to handle, and can be constructed very quickly. Moreover, they are cheap, and do not need formwork or skilled workers. They can be designed to compensate for the stiffness and strength degradation, and to fit easily inside a moderately damaged reinforced concrete frame.To test the concept, a half-scale, single-story 3D reinforced concrete frame specimen was constructed at the shake-table laboratories of the Kandilli Observatory and Earthquake Research Institute of Bogazici University, and subjected to recorded real earthquake base accelerations. The amplitudes of base accelerations were increased until a moderate damage level is reached. Then, the damaged RC frames was retrofitted by means of steel panels and tested under the same earthquake. The seismic performance of the specimen before and after the retrofit was evaluated using FEMA356 standards, and the results were compared in terms of stiffness, strength, and deformability. The results have confirmed effectiveness of the proposed retrofit scheme.
Effect of laser shot peening without coating on the surface properties and corrosion behavior of 316L steel
NASA Astrophysics Data System (ADS)
Kalainathan, S.; Sathyajith, S.; Swaroop, S.
This paper discusses the results of laser peening without coating on low carbon austenitic stainless steel 316L. Unlike typical experiments on laser peening without coating (LPwC) performed with frequency doubled (green) laser and underwater irradiation, the present study reports LPwC with infrared radiation using thin layer of water as confinement medium. The dependence of laser pulse density on properties such as surface roughness, surface residual stress, microhardness, and corrosion behavior of LPwC specimen were investigated. The magnitude of surface compressive residual stress on laser peened specimen showed appreciable improvement compared to unpeened base material. Microhardness of the specimen improved by 30-40% after LPwC. However, the potentiodynamic polarization study indicated that though there is an enhancement of corrosion potential (Ecorr), the corrosion current density (Icorr) increased with increase in laser pulse density.
Characterisation of the Flow Properties of the Quenchenable Ultra High Strength Steel 22MnB5
M. Merklein; J. Lechler; M. Geiger
Nowadays in the automobile industry more and more high strength steels find their application. For their processing innovative forming technologies, like the non-isothermal hot stamping process, are required. With regard to a reliable numerical process design the knowledge of the thermal and thermo-mechanical properties is essential. Within this paper an experimental setup will be introduced, which enables the determination of
G. Madhusudhan Reddy; T. Mohandas; A. Sambasiva Rao; V. V. Satyanarayana
Dissimilar metal welding of austenitic (AISI 304)-ferritic (AISI 430) stainless steel has been taken up to understand the influence of the welding process on microstructure and mechanical properties. Fusion welding processes, namely, gas tungsten arc welding (GTAW), electron beam welding (EBW), and friction welding, have been employed. The GTAW and EBW processes were selected to understand the heat input effects,
Changes of microstructures and high temperature properties during high temperature service of Niobium added ferritic stainless steels
Nobuhiro Fujita; Keiichi Ohmura; Akio Yamamoto
To improve the fuel economy and clean the exhaust gas of automobiles, the temperature of exhaust gas is getting higher and higher. Niobium added ferritic stainless steels are often being used in automotive exhaust systems, because of their excellent heat resistant properties, especially thermal fatigue resistance, which is very important for materials of exhaust manifold. However, coarse precipitates containing niobium,
Notch-Fatigue Properties of Advanced TRIP-Aided Bainitic Ferrite Steels
NASA Astrophysics Data System (ADS)
Yoshikawa, Nobuo; Kobayashi, Junya; Sugimoto, Koh-ichi
To develop a transformation-induced plasticity (TRIP)-aided bainitic ferrite steel (TBF steel) with high hardenability for a common rail of the next generation diesel engine, 0.2 pct C-1.5 pct Si-1.5 pct Mn-0.05 pct Nb TBF steels with different contents of Cr, Mo, and Ni were produced. The notch-fatigue strength of the TBF steels was investigated and was related to the microstructural and retained austenite characteristics. If Cr, Mo, and/or Ni were added to the base steel, then the steels achieved extremely higher notch-fatigue limits and lower notch sensitivity than base TBF steel and the conventional structural steels. This was mainly associated with (1) carbide-free and fine bainitic ferrite lath structure matrix without proeutectoid ferrite, (2) a large amount of fine metastable retained austenite, and (3) blocky martensite phase including retained austenite, which may suppress a fatigue crack initiation and propagation.
Effect of chromium additions on the mechanical and physical properties and microstructure of Fe-Co-Ni-Cr-Mo-C ultra-high strength steel: Part I
NASA Astrophysics Data System (ADS)
Machmeier, P.; Matuszewski, T.; Jones, R.; Ayer, R.
The effect of chromium additions to an Fe-14Co-10Ni-0.1Mo-0.16C (AF1410 based) secondary hardening steel was evaluated by mechanical and physical properties and by microstructural examination. This unique behavior was extended to encompass a large range of aging temperatures and times that may be encountered during commercial thermal treatment and/or welding. In the aging range of 482 to 550 ░C, an increase in chromium from 2 to 3% in the AF1410 based steel resulted in a substantial strength decrease concomitant with an increase in toughness. This behavior is related to a peak hardening shift, early M2C carbide coarsening, and an increase in reverted austenite for the 1 wt% Cr increase. The increased aging kinetics resulting from the 3Cr steel caused a faster dissolution of Fe3C and rapid changes in chromium partitioning in the (Mo,Cr)2C carbide resulting in a coherency loss with a corresponding decrease in lattice parameter. The kinetics of the secondary hardening reaction, for the two steels, was determined by resistivity data for changes in aging parameters (time/temperature).
Measurement of irradiation effects in a RPV steel by ball indentation technique and magnetic Barkhausen noise
NASA Astrophysics Data System (ADS)
Kim, In-Sup; Park, Duck-Gun; Byun, Thak-Sang; Hong, Jun-Hwa
Effects of neutron dose on the mechanical and magnetic properties of a SA508-3 nuclear pressure vessel steel were investigated by using ball indentation test technique and magnetic Barkhausen noise (BN) measurements. The samples were irradiated in a research reactor up to 1018n/cm2 (E>1 MeV) at 70 ░C. The yield strength and flow curve were evaluated from the indentation load-depth curves. The change of mechanical properties showed characteristic trend with respect to neutron dose, namely near plateau, rapid increase and slow increase. On the other hand, the BN varied in a reverse manner, a slow decrease up to a neutron dose of 1016n/cm2, followed by a rapid decrease up to a dose of 1018n/cm2.
Properties of a modified type 329 weldable and SCC (stress corrosion cracking) resistant stainless steel
A new 44LN ferritic-austenitic steel has been developed which contains less carbon and more nickel and nitrogen than 329 steels and is 50-60% austenitic. Its ductile-to-brittle transition was more gradual than that of 329 steel. Its 475┬░C embrittlement was delayed compared with 329 steel, but it was more sensitive to sigma-phase embrittlement. In tests for resistance to general and oxidizing
Effect of heat treatment and nitriding on the magnetic properties of austenitic steels
M. M. Belenkova; A. V. Kostenko; M. N. Mikheev; ╔. ╔. Stoinskaya; T. M. Pogrebetskaya; A. A. Yurgenson
1.A change of the normalizing temperature of steel A from 1070 to 1150░C and also an additional aging for 8 hrs at 800░C have practically no effect on the magnetic susceptibility of this steel.2.Nitriding changes considerably the magnetic permeability of the steels in question. The nitrided case of both austenitic steels is ferromagnetic, this being due to the formation of
Structure and mechanical properties of the three-layer material based on a vanadium alloy and corrosion-resistant steel
NASA Astrophysics Data System (ADS)
Nikulin, S. A.; Rozhnov, A. B.; Nechaikina, T. A.; Rogachev, S. O.; Zavodchikov, S. Yu.; Khatkevich, V. M.
The quality of three-layer pipes has been studied; they are manufactured by hot pressing of a three-layer assembly of tubular billets followed by forging and cold rolling. The operating core is made from a V-4Ti-4Cr alloy. The protective claddings are made from corrosion-resistant steels of two grades, 08Kh17T and 20Kh13. The results of investigation into the structure and microhardness of the junction zone of steel and the vanadium alloy, which includes a contact zone and a transition diffusion layer, are reported. The 08Kh17T steel is shown to be a preferred cladding material.
Improvement of wear resistance of sprayed layer on 52100 steel by friction stir processing
NASA Astrophysics Data System (ADS)
Rahbar-kelishami, A.; Abdollah-zadeh, A.; Hadavi, M. M.; Seraj, R. A.; Gerlich, A. P.
The influence of friction stir processing (FSP) on wear resistance is studied on a thermally sprayed coating in terms of microstructure and mechanical properties. A high-chromium steel coating sprayed on AISI 52100 steel has been processed, and it is shown that FSP can improve the sprayed layer wear resistance compared to the as-sprayed and quenched and tempered condition. It is suggested that improved toughness is the main contribution to wear performance rather than hardness. It is observed that FSP provides increased hardness and toughness simultaneously, while tempering of the quenched AISI 52100 steel increases toughness while hardness decreases.
High-temperature properties and microstructural stability of hot-work tool steels
A. Medvedeva; J. Bergstr÷m; S. Gunnarsson; J. Andersson
Indexable insert tools for machining operations are in service exposed to high temperatures and cyclic mechanical loads. Secondary hardening steels such as hot-work steels are commonly used for tools subjected to thermal exposure. However, these steels, highly alloyed with strong carbide forming elements as Cr, V and Mo, are generally difficult to machine and machining represents a large fraction of
Fabrication of high nitrogen austenitic stainless steels with excellent mechanical and pitting corrosion properties
Hua-bing Li; Zhou-hua Jiang; Yang Cao; Zu-rui Zhang
A series of high nitrogen austenitic stainless steels were successfully developed with a pressurized electroslag remelting furnace. Nitride additives and deoxidizer were packed into the stainless steel pipes, and then the stainless steel pipes were welded on the surface of an electrode with low nitrogen content to prepare a compound electrode. Using Si3N4 as a nitrogen alloying source, the silicon
Relative effect(s) of texture and grain size on magnetic properties in a low silicon non-grain oriented electrical steel
NASA Astrophysics Data System (ADS)
PremKumar, R.; Samajdar, I.; Viswanathan, N. N.; Singal, V.; Seshadri, V.
Hot rolled low Si (silicon) non-grain oriented electrical steel was cold rolled to different reductions. Cold rolled material was subsequently recrystallized, 650░C and 2 h, and then temper rolled (to 7% reduction) for the final grain growth annealing and decarburization treatment at 850░C for 2-24 h. The development of texture, grain size and magnetic properties were characterized at different stages of processing. Effect of texture on magnetic properties (watt loss and permeability) was observed to be best represented by the ratio of volume fractions of (1 1 1)
Grain boundary segregation in boron added interstitial free steels studied by 3-dimensional atom probe
K. Seto; D. J. Larson; P. J. Warren; G. D. W. Smith
The development of deep-drawable sheet steels is of particular significance for the automotive industry. Titanium and\\/or niobium added extra-low carbon interstitial free (IF) steels are key materials. The virtually complete removal of carbon and nitrogen should lead to superior forming properties. However, the lack of solute carbon at grain boundaries significantly decreases the bonding force at the interfaces, which often
Surface modification of superaustenitic and maraging stainless steels by low-temperature gas-phase carburization
NASA Astrophysics Data System (ADS)
Gentil, Johannes
Low-temperature gas-phase carburization of 316L austenitic stainless steel was developed in recent years by the Swagelok company. This process generates great mechanical and electrochemical surface properties. Hardness, wear resistance, fatigue behavior, and corrosion resistance are dramatically improved, while the formation of carbides is effectively suppressed. This new technique is of technical, economical, but especially of scientific interest because the surface properties of common stainless steel can be enhanced to a level of more sophisticated and more expensive superalloys. The consequential continuation of previous research is the application of the carburization process to other steel grades. Differences in chemical composition, microstructure, and passivity between the various alloys may cause technical problems and it is expected that the initial process needs to be optimized for every specific material. This study presents results of low-temperature carburization of AL-6XN (superaustenitic stainless steel) and PH13-8Mo (precipitation-hardened martensitic stainless steel). Both alloys have been treated successfully in terms of creating a hardened surface by introducing high amounts of interstitially dissolved carbon. The surface hardness of AL-6XN was increased to 12GPa and is correlated with a colossal carbon supersaturation at the surface of up to 20 at.%. The hardened case develops a carburization time-dependent thickness between 10mum after one carburization cycle and up to 35mum after four treatments and remains highly ductile. Substantial broadening of X-ray diffraction peaks in low-temperature carburized superaustenitic stainless steels are attributed to the generation of very large compressive biaxial residual stresses. Those large stresses presumably cause relaxations of the surface, so-called undulations. Heavily expanded regions of carburized AL-6XN turn ferromagnetic. Non-carburized AL-6XN is known for its outstanding corrosion resistance, which is not impaired upon carburization. The passive film as analyzed by XPS is fully intact. Carbon concentration levels in PH13-8Mo reach 10 at.% and correlate with a surface hardness of up to 14GPa. Indication for the transformation from martensite to austenite during the process are observed. In this context, the shape of the carbon concentration-depth profile can be explained. Also the absence of carbides, as analyzed by TEM, can be rationalized. Upon cooling to room temperature, most of the austenite backtransforms into martensite and the surface regains its ferromagnetic properties. Compressive biaxial residual stresses in carburized PH13-8Mo are measured around (2--2.5)GPa. The applied low-temperature carburization process gives rise to a substantial loss in corrosion resistance of PH13-8Mo. Possible reasons including the observed formation of internal and external oxides as well as the change in alloy composition are discussed. Due to the penetration depth of X-rays into the probed specimen surface, a carbon concentration gradient may cause detectable asymmetry of diffraction peaks for certain alloys and under certain conditions. For the first time, this effect is rationalized, explained, and demonstrated on the basis of measured data.
Strengthening of ultra-low carbon steels by laser melting treatment
NASA Astrophysics Data System (ADS)
Kurosawa, Nobutaka; Hirose, Akio; Kobayashi, Kojiro F.
In order to reduce the weight of automobiles, the laser transformation hardening response of ultra-low carbon steels (0.003%C) was investigated by comparison with the response of low carbon steels (0.08%C). The effects of the nitrogen and titanium content on hardness are discussed. In the low carbon steels, the hardness of the weld metal showed little change with increases in the titanium content. However, in the ultra-low carbon steels, hardness increased with increasing titanium content. In the low carbon steels, the microstructures of the weld metal, which were comprised mainly of martensite, changed little with increasing titanium content. On the other hand, in the utlra-low carbon steels, the microstructures were bainitic ferrite, and the grains were refined with increasing titanium content. With increasing N2 content in the shielding gas, the hardness of the weld metal increased due to nitrogen absorption in the weld metal. Although the nitrogen contents of the ultra-low carbon steel welds were equivalent to those in the low carbon steel welds, the hardness increments of the former were larger than those of the latter. It was confirmed that increasing the N2 content of the shielding gas is beneficial for strengthening ultra-low carbon steels by laser transformation hardening.
The effect of aluminium on mechanical properties and deformation mechanisms of hadfield steel single crystals
E. G. Zakharova; I. V. Kireeva; Y. I. Chumlyakov; A. A. Shul'Mina; H. Sehitoglu; I. Karaman
On single crystals of Hadfield steel (Fe-13Mn-1.3C, Fe-13Mn-2.7Al-1.3C, wt.%) the systematical investigations of deformation mechanisms - slip and twinning, stages of plastic flow, strain hardening coefficient depending on orientation of tensile axis have been carried out by methods of optical and electron microscopy, x-ray analysis. Is has been shown that the combination of low stacking fault energy (gamma{SF}=0.03J\\/m^2) with high
Mechanical Properties of Reinforcing Steel and Fatigue Behavior in Corrosive Environment
Ch. Alk. Apostolopoulos; D. Michalopoulos
Corrosion of reinforcing steel has a great impact on the mass reduction and high- and low-cycle fatigue. An experimental study\\u000a showed that the mass loss, the fatigue limit and the life expectancy were reduced by approximately 1.50-3.00%, 20-40%, and\\u000a 55-75%, respectively, according to the level of corrosion. Low-cycle strain controlled fatigue testing under ?1% and ?2.5%\\u000a constant amplitude strain, indicated
Microstructural evolution and mechanical properties of aging high nitrogen austenitic stainless steels
Zhou-Hua Jiang; Zu-Rui Zhang; Hua-Bing Li; Zhen Li; Ma Qi-Feng
The microstructural evolution of 18Cr18Mn2Mo0.77N high nitrogen austenitic stainless steel in aging treatment was investigated\\u000a by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show\\u000a that hexagonal intergranular and cellular Cr2N with a=0.478 nm and c=0.444 nm and body-centered cubic intermetallic ? phase with a=0.892 nm precipitate gradually in the isothermal aging treatment. The
A literature survey on the effects of neutron irradiation on impact and ; other mechanical properties of both ferritic steels and austenitic stainless ; steels is presented.The materials studied included carbon and low alloy steels ; such as: ASTM A-212B, ASTM A-201, ASTM A-301B (CR-Mo), ASTM A-106 (coarse and ; fine grained), ASTM A-285, ASTM A-302B (Mn-Mo), ASTM A-353, ASTM
Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing
NASA Astrophysics Data System (ADS)
Bressan, Josķ Divo; Schopf, Roberto Alexandre
Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness only. However, there are others parameters which influences wear such as: fracture toughness, type of crystalline structure and the occurrence of hard precipitate in the metallic matrix and also its nature. In the present investigation, the wear mechanisms acting in tool steels were analyzed and, by normalized tests, wear resistance performance of nine different types of tool steels were evaluated by pin-on-disc testing. Conventional tool steels commonly used in tooling such as AISI H13 and AISI A2 were compared in relation to tool steels fabricated by sintering process such as Crucible CPM 3V, CPM 9V and M4 steels. Friction and wear testing were carried out in a pin-on-disc automated equipment which pin was tool steel and the counter-face was a abrasive disc of silicon carbide. Normal load of 5 N, sliding velocity of 0.45 m/s, total sliding distance of 3000 m and room temperature were employed. The wear rate was calculated by the Archard's equation and from the plotted graphs of pin cumulated volume loss versus sliding distance. Specimens were appropriately heat treated by quenching and three tempering cycles. Percentage of alloying elements, metallographic analyses of microstructure and Vickers microhardness of specimens were performed, analyzed and correlated with wear rate. The work is concluded by the presentation of a rank of tool steel wear rate, comparing the different tool steel abrasion wear resistance: the best tool steel wear resistance evaluated was the Crucible CPM 9V steel.
Surface nanostructure formation mechanism of 45 steel induced by supersonic fine particles pombarding
Dema Ba; Shining Ma; Changqing Li; Fanjun Meng
By means of supersonic fine particles bombarding (SFPB), a nanostructured surface layer up to 15 ?m was fabricated on a 45 steel plate with ferrite and pearlite phases. To reveal the grain refinement mechanism of SFPB-treated 45 steel, microstructure features of various sections in the treated surface were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission
Wear mechanism of stainless steel confirmed by applications of phase-transformation of itself and CCD camera
T Hisakado; K Akiyama; K Matsuzawa; H Ishigaki
For the combination of three kinds of diamond sliders with various tip radii and the stainless steel (SUS 304) disks with phase-transformation properties, wear test was carried out under unlubricated condition at a sliding speed of 48¢59 mm\\/s, and under load ranges of 0.5¢2.0 N. The measurement of the displacement due to magnetic force generated by frictional force, the topographical
A Study of Microstructure and Mechanical Properties of Grade 91 Steel A-TIG Weld Joint
NASA Astrophysics Data System (ADS)
Arivazhagan, B.; Vasudevan, M.
In the present study, A-TIG welding was carried out on grade 91 steel plates of size 220 ū 110 ū 10 mm using the in-house developed activated flux to produce butt-joints. The room-temperature impact toughness of the A-TIG as-welded joint was low due to the presence of untempered martensite matrix despite the low microinclusion density caused by activated flux and also low ?-ferrite (<0.5 %) content. Toughness after postweld heat treatment (PWHT) at 760 ░C-2 h was 20 J as against the required value of 47 J as per the specification EN: 1557:1997. However, there was a significant improvement in impact toughness after PWHT at 760 ░C for 3 h. The improvement in toughness was attributed to softening of martensite matrix caused by precipitation of carbides due to tempering reactions. The precipitates are of type M23C6, and they are observed at grain boundary as well as within the grains. The A-TIG-processed grade 91 steel weld joint was found to meet the toughness requirements after PWHT at 760 ░C-3 h. Observations of fracture surfaces using SEM revealed that the as-welded joint failed by brittle fracture, whereas post-weld heat-treated weld joints failed by decohesive rupture mode.
Constitutive modeling and finite element methods for TRIP steels
I. Papatriantafillou; M. Agoras; N. Aravas; G. Haidemenopoulos
A constitutive model that describes the mechanical behavior of steels exhibiting ōTRansformation Induced Plasticityö (TRIP) during martensitic transformation is presented. Multiphase TRIP steels are considered as composite materials with a ferritic matrix containing bainite and retained austenite, which gradually transforms into martensite. The effective properties and overall behavior of TRIP steels are determined by using homogenization techniques for nonlinear composites.
Influence of Isothermal Bainite Transformation Time on Microstructure and Mechanical Properties of Hot-Dip Galvanized TRIP Steel
NASA Astrophysics Data System (ADS)
Ding, Wei; Tang, Di; Jiang, Haitao; Huang, Wei
The influence of isothermal bainitic transformation (IBT) time on microstructure and mechanical properties of hot-dip galvanized TRIP steel with 0.20C-1.50Mn-1.2Al-0.26Si was investigated using optical microscopy, x-ray diffraction (XRD), Transmission Electron Microscope (TEM), dilatometry, and mechanical testing. This steel has high tensile strength of over 780 MPa with elongation more than 22%. The microstructure of the steel mainly consisted of ferrite, bainite, retained austenite, and martensite. The metastable austenite remaining after bainitic transformation will be transformed into martensite at the final cooling stage. The IBT time affects retained austenite content. When the IBT increased from 10 to 60 s, the amount of retained austenite increased from 9.40 to 15.42%, correspondingly. The IBT time also affects the strain hardening behavior. The n value characteristics of samples for IBT time from 10 to 30 s are similar to those of DP steel; however, the n value of specimen with IBT of 60 s shows features typical of TRIP steel.
Effect of rare earth and titanium additions on the microstructures and properties of low carbon Fe¢B cast steel
Hanguang Fu; Qiang Xiao; Jiacai Kuang; Zhiqiang Jiang; Jian-dong Xing
A new type of wear resistant low carbon Fe¢B cast steel with granular borides can be obtained by alloying with titanium and cerium rare earth (RE). As a result, the as-cast eutectic boride structures of Fe¢B cast steel are greatly refined and a blocky, less interconnected boride network is obtained from continuous ledeburite. After heat treatment, the boride eutectic in
Study of corrosion resistance properties of nitrided carbon steel using radiofrequency N 2\\/H 2 cold plasma process
F. Z. Bouanis; C. Jama; M. Traisnel; F. Bentiss
C38 carbon steel have been plasma-nitrided using a radiofrequency cold plasma discharge treatment in order to investigate the influence of gas composition on corrosion behaviour of nitrided substrates. The investigated C38 steel was nitrided by a RF plasma discharge treatment using two different gas mixtures (75% N2\\/25% H2 and 25% N2\\/75% H2) at different times of plasma-treatment on non-heated substrates.
An investigation on the microstructure and mechanical properties of direct-quenched and tempered AISI 4140 steel
A. H. Meysami; R. Ghasemzadeh; S. H. Seyedein; M. R. Aboutalebi
Direct quenching (DQ) process is an appropriate method in steels heat treatment field. This method enhances production rate, reduces energy consumption and decreases environment contamination. In this study hot-rolled AISI 4140 steel billets with different diameters (75,80,85,100,105 and 115mm) and 20m length were quenched directly in a water tank. Also some samples with similar size and composition were provided by
Grain boundary segregation in boron added interstitial free steels studied by 3-dimensional atom probe
Seto, K. [Kawasaki Steel Corp., Chiba (Japan). Technical Research Labs.] [Kawasaki Steel Corp., Chiba (Japan). Technical Research Labs.; Larson, D.J.; Warren, P.J.; Smith, G.D.W. [Univ. of Oxford (United Kingdom). Dept. of Materials] [Univ. of Oxford (United Kingdom). Dept. of Materials
The development of deep-drawable sheet steels is of particular significance for the automotive industry. Titanium and/or niobium added extra-low carbon interstitial free (IF) steels are key materials. The virtually complete removal of carbon and nitrogen should lead to superior forming properties. However, the lack of solute carbon at grain boundaries significantly decreases the bonding force at the interfaces, which often causes intergranular brittle fracture when deeply drawn steel sheets are subjected to impact deformation at low temperature. This phenomenon is called secondary working embrittlement (SWE), and is a major problem when solute atoms such as phosphorus, manganese or silicon are added to increase the tensile strength of the steels. Small amounts of boron, which does not affect the formability of the steels significantly, are usually added as a remedial measure in such cases. The 3-dimensional atom probe (3DAP) combined with field ion microscopy (FIM) has the ability to produce 3-dimensional images from regions approximately 20nm*20nm*100nm in size, and identify each atomic species and the relative location of each atom with nearly lattice resolution. In this study, a combination of these methods was applied to produce FIM tips of IF steel containing grain boundaries. The authors report here the first observations of the segregation of boron in IF steels using 3DAP.
An investigation into the applicability of Barkhausen noise technique in evaluation of machining properties of high carbon steel parts with different degrees of spheroidization
NASA Astrophysics Data System (ADS)
Jarrahi, Faezeh; Kashefi, Mehrdad; Ahmadzade-Beiraki, Esmaeel
Capability of Barkhausen noise (BN) technique in evaluation of spheroidizing process and determination of the consequent machining properties were investigated. Samples with different degrees of spheroidization were produced from AISI 1060 steel. The microstructure was characterized using SEM metallographic image analysis. Machining properties were evaluated in terms of machining force and surface roughness. The machining properties showed a decrease followed by an increase with increasing spheroidization degree. BN parameters of RMS and peak height values exhibited an increase followed by a decline with increasing spheroidization. Good resolution of peak height parameter in determination of spheroidizing degree provided to define a controlling range (peak height values bigger than 3800 mV) in which the optimum machining properties are achieved.
Effect of substrate temperature on the structural properties of magnetron sputtered titanium nitride thin films with brush plated nickel interlayer on mild steel
NASA Astrophysics Data System (ADS)
Subramanian, B.; Ashok, K.; Jayachandran, M.
Thin films of titanium nitride (TiN) were prepared on mild steel (MS) by a physical vapor deposition (PVD) method namely direct current reactive magnetron sputtering. With the aim of improving the adhesion of TiN layer an additional Nickel interlayer was brush plated on the steel substrates prior to TiN film formation. The phase has been identified with X-ray diffraction (XRD) analysis, and the results show that the prominent peaks observed in the diffraction patterns correspond to the (1 1 1), (2 0 0) and (2 2 2) planes of TiN. Cross-sectional SEM indicated the presence of dense columnar structure. The mechanical properties (modulus and hardness) of these films were characterized by nanoindentation.
Effect of copper content, initial structure, and scheme of treatment on magnetic properties of ultra-thin grain oriented electrical steel
NASA Astrophysics Data System (ADS)
Lobanov, M. L.; Rusakov, G. M.; Redikul'tsev, A. A.
The effect of the copper content, initial structure, and scheme of treatment on the magnetic properties of an ultra-thin grain oriented electrical steel has been investigated. In the material with copper and an initial sharp texture, the nucleation of new grains upon primary recrystallization is connected with deformation twins; in the samples without copper and with copper and diffuse texture, it is connected predominantly with shear bands and transition bands. Upon heating at a rate of ś0.004 K/s, the temperature of primary recrystallization in the copper-bearing samples is considerably higher than in the copper-free material. Upon heating at a rate of ś4 K/s the appearance of new grains occurs almost simultaneously for all of the studied samples. In the samples with copper and initial sharp texture after annealing at 1050░C, a significant part of the volume is occupied by grains that had undergone normal grain growth; in the samples without copper and with copper and diffuse texture, anomalous growth is hardly observed at all. To obtain high final magnetic properties of the ultra-thin grain oriented electrical steel produced by the Littmann method, it has been suggested to use an grain oriented electrical steel with 0.5% Cu that exhibits the diffuse orientation of grains as the workpiece.
Necking propagated deformation behavior of layer-structured steel prepared by co-warm rolled surface nanocrystallized 304 stainless steel
A. Y. Chen; J. B. Zhang; J. Lu; W. Lun; H. W. Song
Surface nanocrystallized 304ss sheets prepared by surface mechanical attrition technique were co-warm rolled at 500Ā░C to obtain layer-structured steel with alternate nanocrystalline layer and coarse grained layer. Tensile test results revealed that a novel tensile deformation behavior characterized by sliding and necking propagation were presented compared to the base material. In the process of tensile deformation, a sliding band occurred
Removal of contaminants in leachate from landfill by waste steel scrap and converter slag.
Oh, Byung-Taek; Lee, Jai-Young; Yoon, Jeyong
This study may be the first investigation to be performed into the potential benefits of recycling industrial waste in controlling contaminants in leachate. Batch reactors were used to evaluate the efficacy of waste steel scrap and converter slag to treat mixed contaminants using mimic leachate solution. The waste steel scrap was prepared through pre-treatment by an acid-washed step, which retained both zero-valent iron site and iron oxide site. Extensive trichloroethene (TCE) removal (95%) occurred by acid-washed steel scrap within 48 h. In addition, dehalogenation (Cl(-) production) was observed to be above 7.5% of the added TCE on a molar basis for 48 h. The waste steel scrap also removed tetrachloroethylene (PCE) through the dehalogenation process although to a lesser extent than TCE. Heavy metals (Cr, Mn, Cu, Zn, As, Cd, and Pb) were extensively removed by both acid-washed steel scrap and converter slag through the adsorption process. Among salt ions (NH (4)(+) , NO (3)(-) , and PO (4)(3-) ), PO (4)(3-) was removed by both waste steel scrap (100% within 8 h) and converter slag (100% within 20 min), whereas NO (3)(-) and NH (4)(+ ) were removed by waste steel scrap (100% within 7 days) and converter slag (up to 50% within 4 days) respectively. This work suggests that permeable reactive barriers (PRBs) with waste steel scrap and converter slag might be an effective approach to intercepting mixed contaminants in leachate from landfill. PMID:17492478
Improvement of sag resistance by the addition of tungsten in Si-Cr-Mo-V steels
Nam, W.J. [POSCO Technical Research Lab., Pohang (Korea, Republic of)] [POSCO Technical Research Lab., Pohang (Korea, Republic of); Lee, C.S. [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials] [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials; Ban, D.Y. [KISWIRE R and D Center, Pusan (Korea, Republic of)] [KISWIRE R and D Center, Pusan (Korea, Republic of)
The sag resistance of automobile suspension springs is defined, in general, as the resistance to the plastic deformation of springs during repeated loading in service. Since it is one of the most important properties required for high strength spring steels, earlier works on high strength spring steels have concentrated on the improvement of the sag resistance by adding alloying elements or by changing processing treatments. However, the effect of W, a carbide former, on the sag resistance has not been clarified yet. It is, therefore, of interest to investigate the effect of the W addition on the sag resistance. The evaluation of the sag resistance is usually performed by direct static and dynamic tests on prototype springs. However, such a direct method leads to high costs and long testing time. Thus, Furr has proposed the torsional Bauschinger test as one of convenient testing methods, which is related to the Bauschinger effect. He has also shown that the size of hysteresis loops generated in the torsional Bauschinger test has a close relationship with the sag resistance of springs. Ohara, et al. have investigated the correlation between a direct testing on prototype springs and the torsional Bauschinger test, and have shown that a larger loop area in the torsional Bauschinger test represents a higher sag resistance. In view of the foregoing, the purposes of this investigation are to examine the effects of the W addition on (a) the microstructural evolution during tempering and (b) the sag resistance, using the torsional Bauschinger test, for 0.6C-1.5Si-0.5Cr-0.1Mo-0.2V (wt.%) spring steels.
Microstructure homogenization control of Nb-bearing X65 pipeline steel by the CSP process
NASA Astrophysics Data System (ADS)
Li, Ming-Yang; Liu, Ya-Zheng; Zhu, Tao; Wang, Ying
In order to get the controlled methods of microstructure homogenization and high strengthening-toughening combination by compact strip production (CSP) rolling, the dynamic recrystallization characteristics of each pass were obtained during CSP rolling using a Gleeble-1500 thermal mechanical simulator. Then, the CSP process was simulated by laboratory rolling experiment. Through thermal mechanical simulation experiment and laboratory rolling experiment, a design idea of Nb-bearing pipeline steel by CSP can be obtained as the following: the level of dynamic recrystallization behavior should be increased through the reasonable balance of high deformation temperature and deformation amount in F1 and F2 passes, and F3-F7 passes should be controlled in the austenite non-recrystallization zone. Finally, X65 pipeline steel with microstructure uniformity and good properties was produced by CSP. The yield strength is up to 497 MPa, the tensile strength is up to 563 MPa, the elongation is 30% on average, and the toughness is very good whose Charpy impact value is 110 J on average and drop-weight tear test shearing areas are all 100% at -60, -40, -20, 0, and 20░C.
Characterization of hydroxyapatite coating by pulse laser deposition technique on stainless steel 316 L by varying laser energy
NASA Astrophysics Data System (ADS)
Khandelwal, Himanshu; Singh, Gurbhinder; Agrawal, Khelendra; Prakash, Satya; Agarwal, R. D.
Hydroxyapatite is an attractive biomaterial mainly used in bone and tooth implants because it closely resembles human tooth and bone mineral and has proven to be biologically compatible with these tissues. In spite of this advantage of hydroxyapatite it has also certain limitation like inferior mechanical properties which do not make it suitable for long term load bearing applications; hence a lot of research is going on in the development of hydroxyapatite coating over various metallic implants. These metallic implants have good biocompatibility and mechanical properties. The aim of the present work is to deposit hydroxyapatite coating over stainless steel grade 316 L by pulse laser deposition technique by varying laser energy. To know the effect of this variation, the coatings were than characterized in detail by X-ray diffraction, finite emission-scanning electron microscope, atomic force microscope and energy dispersive X-ray spectroscopy.
Damage detection system of a real steel truss bridge by neural networks
Man Yong Choi; Il-Bum Kwon
The damage detection system of a real steel truss bridge was developed to identify the location and severity of the damaged members. At first, the loading test was performed to characterize the real bridge. The real steel truss bridge was measured by electrical strain gages and accelerometers when the train passed. The measured strains and acceleration were used to refine
Estimation of individual dust exposure by magnetopneumography in stainless steel production
Markku Huvinen; Leo Oksanen; Kalevi Kalliomõki; Pirkko-Liisa Kalliomõki; Markku Moilanen
The objectives of the study were to measure the magnetic dust lung burden of workers in stainless steel production by magnetopneumography (MPG) and to investigate the relationship of the results with air-borne concentrations of dust, total and hexavalent chromium as well as urinary excretion of chromium. There were 128 workers from the chromite mine, sintering plant, ferrochrome smelter, stainless steel
Lap welding of titanium and mild steel sheets by seam welding
K. Nishio; M. Kato; T. Yamaguchi; T. Tokunaga; A. Matsumoto
Titanium, a metal with superior sea water corrosion resistance, is increasingly used in titanium clad steel applications for ocean structures. Titanium clad steel is normally manufactured by hot rolling or explosive deposition. Joining of titanium and iron leads to the formation of hard and brittle intermetallic compounds that impair the bond strength. It is therefore necessary to use an insert
Rapid prototyping by consolidation of stainless steel powder using an electrical arc
A. Rangesh; William ONeill
Purpose ¢ The purpose of this paper is to investigate the feasibility of using a pulsed Tungsten inert gas arc to fully melt and consolidate stainless steel powder onto a stainless steel substrate. The technology aims to bridge the gap between selective laser sintering or laser melting and wire fed weld deposition by providing good quality and better resolution at
Coating of ?-Al2O3 on the stainless steel substrate by electrophoretic deposition method.
Kishida, Satoshi; Ju, Dong-Ying; He, Hong; Li, Yi
?-Al2O3 coatings were prepared on aluminum-free stainless steel (SUS304) by electrophoretic deposition method. Both X-ray diffraction and scanning electron microscopy were used to study the crystalline structure and morphological features of the coatings. Themo gravimetry-differential termal analysis (TG-DTA) is used to study the thermo-chimerical reaction behavior of coatings. Catalytic activity of coatings is determined by degrading of NOx. The results indicated that the thickness of the coatings onto SUS304 could reach 5 ?m without any exfoliation at optimized conditions. Catalytic properties of samples coated by electrophoretic deposition method were highly enhanced as compared with that of samples prepared by the dip coating method. PMID:25084405
Effect of Heat Treatment Process on Mechanical Properties and Microstructure of a 9% Ni Steel for Large LNG Storage Tanks
NASA Astrophysics Data System (ADS)
Zhang, J. M.; Li, H.; Yang, F.; Chi, Q.; Ji, L. K.; Feng, Y. R.
In this paper, two different heat treatment processes of a 9% Ni steel for large liquefied natural gas storage tanks were performed in an industrial heating furnace. The former was a special heat treatment process consisting of quenching and intercritical quenching and tempering (Q-IQ-T). The latter was a heat treatment process only consisting of quenching and tempering. Mechanical properties were measured by tensile testing and charpy impact testing, and the microstructure was analyzed by optical microscopy, transmission electron microscopy, and x-ray diffraction. The results showed that outstanding mechanical properties were obtained from the Q-IQ-T process in comparison with the Q-T process, and a cryogenic toughness with charpy impact energy value of 201 J was achieved at 77 K. Microstructure analysis revealed that samples of the Q-IQ-T process had about 9.8% of austenite in needle-like martensite, while samples of the Q-T process only had about 0.9% of austenite retained in tempered martensite.
Effects of Mixing the Steel and Carbon Fibers on the Friction and Wear Properties of a PMC Friction Material
NASA Astrophysics Data System (ADS)
Bagheri Kazem Abadi, Sedigheh; Khavandi, Alireza; Kharazi, Yosouf
Friction, fade and wear characteristics of a PMC friction material containing phenolic resin, short carbon fiber, graphite, quartz, barite and steel fiber were investigated through using a small-scale friction testing machine. Four different friction materials with different relative amounts of the carbon fiber and steel fiber were manufactured and tested. Comparing with our previous work which contained only steel fiber as reinforcement, friction characteristics such as fade and recovery and wear resistance were improved significantly by adding a small amount of carbon fiber. For the mixing of carbon and steel fiber, the best frictional and wear behavior was observed with sample containing 4 weight percentage carbon fiber. Worn surface of this specimen was observed by optical microscopy. Results showed that carbon fibers played a significant role in the formation of friction film, which was closely related to the friction performance. The brake pad with Steel fibers in our previous work, showed low friction coefficient and high wear rate. In addition, a friction film was formed on the surface with a relatively poor quality. In contrast, the samples with mixing the steel and carbon fiber generated a stable friction film on the pad surface, which provided excellent friction stability with less wear.
Charpy toughness and tensile properties of a neutron-irradiated stainless steel submerged arc weld cladding overlay
Corwin, W.R.; Berggren, R.G.; Nanstad, R.K.
The cladding was applied to a pressure vessel steel plate by the submerged arc, single-wire, oscillating-electrode method. Three layers of cladding provided a thickness adequate for fabrication of test specimens. The first layer was type 309, and the upper two layers were type 308 stainless steel. The type 309 was diluted considerably by excessive melting of the base plate. Specimens were taken from near the base plate-cladding interface and also from the upper layers. Charpy V-notch and tensile specimens were irradiated at 288/sup 0/C to a fluence of 2 x 10/sup 23/ neutrons/m/sup 2/ (>1 MeV). When irradiated, both types 308 and 309 cladding increased 5 to 40% in yield strength and slightly increased in ductility in the temperature range from 25 to 288/sup 0/C. All cladding exhibited ductile-to-brittle transition behavior during impact testing. The type 308 cladding, microstructurally typical of that in reactor pressure vessels, showed very little degradation in either upper-shelf energy or transition temperature due to irradiation. Conversely, the impact properties of the specimens containing the highly diluted type 309 cladding, microstructurally similar to that produced during some off-normal welding conditions in existing reactors, experienced significant increases in transition temperature and drops of up to 50% in upper-shelf energy. The impact energies of the Charpy specimens containing the type 309 layer strongly reflected the amount of the type 309 actually in the specimen, falling into two distinct high- and low-energy populations with the low-energy population corresponding to a higher fraction of type 309 in the specimen.
General corrosion properties of modified PNC1520 austenitic stainless steel in supercritical water as a fuel cladding candidate material for supercritical water reactor
NASA Astrophysics Data System (ADS)
Nakazono, Y.; Iwai, T.; Abe, H.
The Super-Critical Water-cooled Reactor (SCWR) has been designed and investigated because of its high thermal efficiency and plant simplification. There are some advantages including the use of a single phase coolant with high enthalpy but there are numerous potential problems, particularly with materials. As the operating temperature of supercritical water reactor will be between 280░C and 620░C with a pressure of 25MPa, the selection of materials is difficult and important. Austenitic stainless steels were selected for possible use in supercritical water systems because of their corrosion resistance and radiation resistance. The PNC1520 austenitic stainless steel developed by Japan Atomic Energy Agency (JAEA) as a nuclear fuel cladding material for a Na-cooled fast breeder reactor. The corrosion data of PNC1520 in supercritical water (SCW) is required but does not exist. The purpose of the present study is to research the corrosion properties for PNC1520 austenitic stainless steel in supercritical water. The supercritical water corrosion test was performed for the standard PNC1520 (1520S) and the Ti-additional type of PNC1520 (1520Ti) by using a supercritical water autoclave. Corrosion tests on the austenitic 1520S and 1520Ti steels in supercritical water were performed at 400, 500 and 600░C with exposures up to 1000h. The amount of weight gain, weight loss and weight of scale were evaluated after the corrosion test in supercritical water for both austenitic steels. After 1000h corrosion test performed, the weight gains of both austenitic stainless steels were less than 2 g/m2 at 400░C and 500░C . But both weight gain and weight loss of 1520Ti were larger than those of 1520S at 600░C . By increasing the temperature to 600░C, the surface of 1520Ti was covered with magnetite formed in supercritical water and dissolution of the steel alloying elements has been observed. In view of corrosion, 1520S may have larger possibility than 1520Ti to adopt a supercritical water reactor core fuel cladding.