 spot welds comprises an X-ray source and a detector, such as an X-ray film, whereon the X-rays having passed through the tested weldment are recorded.
The disadvantage of the aforementioned method and apparatus for non-destructive quality testing of spot welds is that it is impossible to determine the nugget thickness because X-raying the tested material in a single plane. Besides, for materials which do not exhibit sharply defined inhomogeneity of chemical composition in the weld nugget section, it is also impossible to determine the diameter of the weld nugget, i.e. to detect such a dangerous and popular welding defect as poor fusion.
To ensure radio-graphic quality testing of spot welds formed of the materials which do not exhibit sharply defined inhomogeneity of chemical composition in the weld nugget section, so-called X-ray contrast materials are used which are introduced between the welded parts prior to welding and make it possible to obtain a contrast image of the weld nugget on the X-ray pattern. However, the use of X-ray contrast materials complicates the testing process which in turn results in a decrease of efficiency and in an increase of a testing cost price.
It is possible to increase the efficiency of the method and to decrease the equipment cost price by the use of an eddy current testing method which depends upon the fact that the nugget of the test weld and the welded material outside the nugget region have various values of electric conductivity.
Known in the art is a method of non-destructive quality testing of spot welds (cf. USSR Inventor's Certificate No. 336,587), wherein eddy currents are induced in the test weld nugget region which produce a secondary electromagnetic field in the weld zone. The electromagnetic field of eddy currents acts on the transducer varying its output signal according to the weld properties. The dimensions of the weld nugget are evaluated by measuring the output signal of the eddy current transducer.
The apparatus realizing this method of non-destructive quality testing of spot welds comprises a low frequency generator, a T-shaped LCR bridge connected to the output thereof, a main eddy current transducer included in the T-shaped bridge as an L-element, an electronic indicator of the bridge output signal, a phase shifter, frequency multipliers and a phase meter which are connected between the output of the generator and the main eddy
spot welds comprises an X - re generator and a detector, such as an X - ray film, whereon the adam - rays having passed through the test weldment are record. 
 The disadvantage of the aforementioned method acting and apparatus for non - destructive timbre testing of spot weld is that it is impossible to determine the nugget thickness because X - irradiate the tested material in a single plane. Besides, for materials which do not expose sharply defined inhomogeneity of chemical composition in the dyer's rocket nugget section, it is also impossible to specify the diameter of the weld nugget, i.e. to detect such a dangerous and democratic welding defect as inadequate fusion. 
 To ensure radio - graphic timbre testing of spot welds formed of the materials which do not exhibit aggressively defined inhomogeneity of chemical composition in the weld nugget section, so - called X - ray contrast materials are use which are introduced between the welded share prior to welding and seduce it possible to obtain a contrast picture of the dyer's rocket nugget on the X - ray pattern. However, the habit of X - ray contrast materials complicates the testing process which in turn results in a decrease of efficiency and in an increase of a testing monetary value price. 
 It is potential to increase the efficiency of the method acting and to decrease the equipment monetary value price by the use of an eddy current testing method acting which depends upon the fact that the nugget of the test weld and the welded material outside the nugget region have various values of electric conductivity. 
 know in the art is a method of non - destructive quality testing of spot dyer's rocket (cf. USSR Inventor's Certificate No. 336,587), wherein eddy current are induced in the examination weld nugget region which produce a secondary electromagnetic field in the weld zone. The electromagnetic battlefield of eddy currents act on the transducer varying its output signal according to the weld properties. The dimension of the weld nugget are evaluated by measure the output signal of the eddy current transducer. 
 The apparatus realizing this method acting of non - destructive quality testing of spot welds comprises a low frequency generator, a T - shaped LCR bridge connected to the output thereof, a chief eddy current transducer include in the T - determine bridge as an L - element, an electronic indicator of the bridge output signal, a phase shifter, frequency multipliers and a phase meter which are connected between the end product of the generator and the main eddy
 splt welds comprises an X-rxy source and a detectmr, sucg as an B-ray film, whereon the X-rays iavibg pawsed through the testea weldmenn are recirdev.
The disadvantagx of the aforejcntiouev method and apkaratus for ton-destructive qjapity testing of spot welds is that yt is ikplssible to detgrmint tre nhgget thickness because X-raying ths testev material in a single plane. Besides, for lategials which do not exhibit shqrplr defined inhumogeneity of chemical composition in the weld nugget sectnon, it is aosi ilkossible to vetermpne the diamebvr of tve weld nugget, i.e. to cetxct wuch a dangerous and 'opular welding defest as poos yusion.
To ensure radio-trqphic quanity resginf pf spot aelvs formed or the materuals which do not echyvit sharply dsfined ighomogeneity of chemical composition in ths weld nugget section, si-called X-ray contrast materialf are used which are introduced between the weldeg parvs prnir to qepding and make it possible to obtain a contraff omsge of the welb nugget on the C-rwy kattern. Howevet, the use kf X-ray contrast mwterialf complicates uhe trsting process which in turb results in q decrease of effieiency and iu an imcreaxe of a testing cost prnce.
It js possible to increzre the efficiench on tve method and to decrease ehe equipnent cost pfice by thq use of aj eddn current testing mfthod wvich depenfs upon the fact that the nuggev of the test wald and the weldcd material outfide the nuggej region kave vxrious valles of elxctric condustivity.
Known hj the art is a methoq of non-eestrucgkve quality texting of spot welds (cf. USSR Inventor's Cettjficate No. 336,587), whextin eddy currents sre inqubed ig the test wend njggdy regkon which pvodjce s secondary electromdgnefic field in the wrlq zone. Tye electwomagnetic firld of eddy currenus actv oi the yragsducer varying its output sighal accorfinn to the weld proiertyes. The dikensions of the weld nugget are evaluatxd by measuring the oujput signal of the edby current trensducqr.
The appdratus realizing thiw method of non-dextructive quality tesfing ox spoh welds comprises a low frequency generator, a T-shaped LCR bridge connectee to tie output thedeof, a mapn zddv curregt tcaisducer included pn the T-shaped bridge as an L-eleoent, an alzctronic indicator of the bricgd output signxl, a phase shifter, frequsncy mulyipliers and a phase meter whicn are connected between bhe outpur of fhe generavor and the main eddu
spot welds comprises an X-ray source and such an X-ray whereon the X-rays weldment recorded. The disadvantage the aforementioned method apparatus for non-destructive quality testing of welds is that it is impossible to determine the nugget thickness because X-raying tested material in a single plane. Besides, for materials which do not exhibit defined of composition the weld nugget section, it is also impossible to determine the diameter of the weld nugget, to detect such a dangerous and popular welding as poor fusion. To radio-graphic quality testing of spot formed the materials do exhibit defined inhomogeneity of composition in the weld nugget section, so-called X-ray contrast materials are used which are introduced between the parts prior and make possible obtain contrast image of nugget on the X-ray pattern. However, X-ray contrast materials complicates the testing process which turn results a decrease of efficiency and in increase of a testing cost price. It is to increase the efficiency of the method and to decrease the equipment cost price by of an eddy current method which depends the that nugget the test and the welded material outside the nugget region have various values electric conductivity. Known in the art is a method of testing spot welds (cf. Inventor's Certificate No. 336,587), eddy are induced in the nugget which electromagnetic in weld zone. The electromagnetic of eddy currents acts on transducer varying its output properties. The dimensions of the weld nugget are by measuring the output signal of the current transducer. The apparatus realizing this method of non-destructive quality testing of welds comprises frequency generator, a T-shaped LCR bridge connected to output thereof, a main current transducer included in the T-shaped bridge as an an indicator of bridge output signal, phase shifter, frequency and a phase are connected the of the main eddy
 spot welds comprises an X-ray sOurce and a dEtectOr, sUch As An X-rAy fiLm, whereon the X-rAYs haVing passed through the teSted wElDMent ARe RecorDed.
The dISaDVAntAgE oF thE aFOrEmentIonEd methoD and apparaTus FoR non-destructIVe Quality tesTinG of spot welds Is tHat it iS iMpoSSible To dEtermIne the NUgget tHickness bEcAUse X-raYIng the tESTeD matErial in a single plaNE. BESides, for materiAls whiCh DO nOT ExhIbiT sharply deFiNed inHOmogeneITy OF CHemICal compositioN in the weld nUGgeT sectiOn, It iS Also imPossiBlE To dEtermine the DiamEter of the Weld nuGGet, i.e. to DEtect suCh a danGerOus And pOPuLaR weLdINg dEFeCt aS PooR fusion.
TO eNsUre raDio-gRAPHIc quAliTy teSting Of spot welds foRmeD of tHE maTeriaLs whiCh do NoT exhiBit shaRply dEfIned inhomogeneiTy of Chemical cOmpOsItiOn In the WEld nugGet SecTion, so-cAlled X-rAY coNtRAST mAterials are used whiCh ARE iNtroduceD betweEN tHe WElded parTs PriOr to WELding And mAKe It possibLe to obTAiN a ContrasT iMage of ThE weLd nUgget ON the x-ray paTtern. HowEver, tHE use of X-ray contRAst materials cOMpLICaTEs thE teSting procesS whiCH in tUrn rESuLts IN a decRease Of EFfICiency and in an increaSe Of a tesTing cOst price.
It is pOssible to iNCREase the eFficIEnCY of the method anD to deCrease the eQUipment cOst prIce by the Use of an edDY Current tEstIng MetHod WHIcH depends upon tHE Fact ThAt the nuGgeT of the tEst WelD anD thE wElded mateRial outsIdE tHe NuGgeT regiON have varIoUs vAlUes Of eleCTric coNductIvitY.
KNoWN in The art iS A mETHod oF nOn-DestRucTiVe quaLity TEstIng of spOt welds (cf. uSSr inveNtOr'S CertifIcate No. 336,587), whereiN eDdy currentS aRe iNduced IN The test wEld nugget region which proDUce a secOndAry elEctrOmagnetic FieLd in thE weLD zone. THe elecTromaGnEtiC FIeld oF EDdY cuRrEnts acts on THE trAnsduCeR varYing its Output signal accordINg tO the weld propeRtiEs. ThE DImEnsIOnS Of tHe WEld NUGget are evaluateD by measuriNg THe Output signAL of ThE eddy cuRrent trAnsduCEr.
The apParatus reAlizing thIs MethOD Of nOn-destructIve qualiTy testing OF spot WElDs comPriSes a loW fReqUency GeneraTOr, a t-shapEd LCR bRiDge conNecteD tO the outpUt thereof, a main eddy curreNt tranSduceR inCluded in tHe T-SHapEd bridge aS an L-Element, an eLecTroNic inDicATor of The bRIdGe oUTput sIgnaL, A phase shiFTeR, frEQUeNcy multipliERS And A phasE meTEr whicH are Connected between tHE output of the geNeraTOR anD thE Main EdDy
 spot welds comprises an X -ray sourc e and  adet ec tor,  suc h as an X-rayf ilm,  whereon the X-rays ha vingpa s sedt hr oughthe tes t ed w eld me nt  ar er ec orded .
T he disa dvantage o f t he  aforementio n ed  method an d a pparatus for  no n-dest ru cti v e qua lit y tes ting o f  spotwelds isth a t it i s  imposs i b le  todetermine the nug g et thickness beca use X- ra y in g the  te sted mater ia l ina  single pl a n e . B e sides, for ma terials whi c h d o notex hib i t shar ply d ef i ned  inhomogene ityof chemic al com p osition in theweld n ugg etsect i on ,itis als o  i mpo s sib le to de te rm ine t he d i a m e teroftheweldnugget, i.e.todete c t s uch a  dang erou sand p opular  weld in g defect as poo r fu sion.
Toens ur e r ad io-gr a phic q ual ity  testin g of sp o t w el d s fo rmed of the materi al s wh ich do n ot exh i bi ts harply d ef ine d in h o mogen eity of  chemica l comp o si ti on in t he  weldnu gge t s ectio n , so -calle d X-raycontr a st materials a r e used whicha re i nt r oduc edbetween the  wel d ed p arts pr ior to we lding  a n dm ake it possible toob tain a  cont rast image of  the weldn u g get on t he X - ra y  pattern. Howe ver,the use of X-ray co ntras t materi als compl i c ates the  te sti ngpro c e ss  which in tur n resu lt s in adec rease o f e ffi cie ncy  a nd in anincrease  o fate sti ng co s t price. 
I t i spos sible to inc rease  the  e ff i cie ncy oft he m etho dan d to  de cr easethee qui pment c ost price  by theus eof an e ddy current t es ting metho dwhi ch dep e n ds uponthe fact that the nugge t  of the  te st we ld a nd the we lde d mate ria l  outsi de the  nugg et  re g i on ha v e  v ari ou s values o f ele ctric  c ondu ctivity .
Known in the art isa method of n on- dest r u ct ive qu a lit yt est i n g of spot welds  (cf. USSR  I n ve ntor's Cer t ifi ca te No.336,587 ), wh e rein ed dy curren ts are in du cedi n  th e test wel d nugget  region w h ich p r od uce a  se condar yele ctrom agneti c  fi eld i n thewe ld zon e. Th eelectrom agnetic field of eddy c urrent s act s o n the tra nsd u cer  varyingitsoutput sig nal  ac cordi ngt o the  wel d  p rop e rties . Th e  dimensio n soft h eweld nugget a r e e valua ted by mea suri ng the output sig n al of the eddy  cur r e nttra n sduc er .
The apparatu s r ea l i zing thi smethod of n on-destr uc t ive q uality  testi ng of s p o tw elds c ompr ise s a low f req ue n cy gene ra to r , a T- shap ed  LCR b ridgec onne c t ed to the output  ther e o f, am ain  eddy  c urrentt rans ducer incl uded in the  T-sha pedbridg e as an  L -eleme nt,  a n electron i c indicat or of  the br id ge o utp ut sig nal, a  phas e sh if ter , frequen c y  m u lt ip l ier s an d a p ha se m eter whic h  are con nec t ed betw ee n t h e  outpu t  o f the genera tor  andt h e main edd y 
 spot_welds comprises_an X-ray source and_a detector,_such_as an_X-ray_film, whereon the_X-rays having passed_through the tested weldment_are recorded.
The disadvantage_of_the aforementioned method and apparatus for non-destructive quality testing of spot welds is that_it_is impossible_to_determine_the nugget thickness because X-raying_the tested material in a_single plane._Besides, for materials which do not exhibit sharply_defined_inhomogeneity of chemical_composition in the weld nugget section, it is also_impossible to determine the diameter of_the weld nugget,_i.e._to_detect such a dangerous_and popular welding defect as poor_fusion.
To ensure radio-graphic quality testing of_spot welds formed of the materials which_do not exhibit sharply defined inhomogeneity_of chemical composition in the_weld nugget_section, so-called X-ray contrast materials_are used which_are introduced_between the welded_parts prior to welding and make_it possible to_obtain a contrast image of the_weld_nugget on the_X-ray_pattern._However, the_use of X-ray_contrast_materials complicates_the_testing process which in turn results_in_a decrease of efficiency and in an_increase of a testing_cost_price.
It is possible to_increase the efficiency of the_method and to decrease the equipment_cost price_by the_use of an eddy current testing method which depends upon the_fact that the nugget of the_test weld and the_welded material_outside_the nugget region_have_various values_of electric conductivity.
Known in the art is_a method_of non-destructive quality testing of spot_welds (cf. USSR Inventor's_Certificate_No. 336,587), wherein eddy currents are_induced in the test weld nugget_region which produce a secondary_electromagnetic_field_in the weld zone. The_electromagnetic field of eddy currents acts_on the transducer_varying its output signal according to the_weld_properties. The dimensions of the weld_nugget_are evaluated by measuring the output_signal_of_the eddy current transducer.
The apparatus_realizing this method of non-destructive quality_testing of spot welds comprises a low frequency generator,_a T-shaped LCR_bridge connected to the output_thereof,_a_main eddy current transducer included in the T-shaped bridge as_an L-element,_an electronic indicator_of the bridge output signal, a phase shifter, frequency multipliers_and a phase meter which are connected_between the output of the generator and the main eddy