MIG Welding Stainless SteelMIG welding is a process suitable for welding of all the main types of stainless steels. Consumables are bare solid wires and are selected to closely match or overmatch the composition of the parent material. Austenitic stainless steels are normally welded with matching consumables and duplex stainless steels with nickel-enriched wires. Ferritic and martensitic alloys may be welded with matching wires or austenitic type wires. Equipment requirements depend on the transfer mode being used and for dip and spray transfer standard MIG equipment may be used. Welding may also be carried out in pulsed transfer mode and here use of a pulsed MIG power source is needed. Conventional wire feed units and welding guns are quite satisfactory too. A variety of shielding gases are available and include argon-oxygen, helium-argon-CO2, and argon-CO2 mixtures. They are selected according to the alloy, application, and weld requirements. Possible problems with MIG welding stainless steels include porosity, lack of fusion, and cracking in susceptible alloys. Often careful attention to a good welding procedure will deal with these. The main safety issues are electrical, radiation, inert compressed gases, and generation of welding fume containing chromium and, possibly, ozone.
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