weld. Improper welding practices can additionally cause sugaring (oxide scaling) and/or heat tint on the backside of the weld. This can be prevented with the use of back-purging gases, backing plates, and fluxes. Post-weld heat treatment is almost always required while preheating before welding is also necessary in some cases. Electric arc welding of type 430 ferritic stainless steel results in grain growth in the HAZ, which leads to brittleness. This has largely been overcome with stabilized ferritic grades, where niobium, titanium, and zirconium form precipitates that prevent grain growth. Duplex stainless steel welding by electric arc is a common practice but requires careful control of the process parameters. Otherwise, the precipitation of unwanted intermetallic phases occurs, which reduces the toughness of the welds. Electric arc welding processes include: Gas metal arc welding, also known as MIG/MAG welding Gas tungsten arc welding, also known as tungsten inert gas (TIG) welding Plasma arc welding Flux-cored arc welding Shielded metal arc welding (covered electrode) Submerged arc welding MIG, MAG and TIG welding are the most common methods. Other welding processes include: Stud welding Resistance spot welding Resistance seam welding Flash welding Laser beam welding Oxy-acetylene welding Stainless steel may be bonded with adhesives such as silicone, silyl modified polymers, and epoxies. Acrylic and polyurethane adhesives are also used in some situations. Production Most of the world's stainless steel production is produced by the following processes: Electric arc furnace (EAF): stainless steel scrap, other ferrous scrap, and ferrous alloys (Fe Cr, Fe Ni, Fe Mo, Fe Si) are melted together. The molten metal is then poured into a ladle and transferred into the AOD process (see below). Argon oxygen decarburization (AOD): carbon in the molten steel is removed (by turning it into carbon monoxide gas) and other compositional adjustments are made to achieve the desired chemical composition. Continuous casting (CC): the molten metal is solidified into slabs for flat products (a typical section is thick and wide) or blooms (sections vary widely but is the average size). Hot rolling (HR): slabs and blooms are reheated in a furnace and hot-rolled. Hot rolling reduces the thickness of the slabs to produce about -thick coils. Blooms, on the other hand, are hot-rolled into bars, which are cut into lengths at the exit of the rolling mill, or wire rod, which is coiled. Cold finishing (CF) depends on the type of product being finished: Hot-rolled coils