The austenitic - ferritic duplex stainless steel wire, of which the main ingredient is 22Cr-9Ni-Mo-N, is available for all-position welding. Since 40% of the weld metal is ferrite, the deposited metal has both the combination property of austenitic stainless steel and the characters of ferritic stainless steel i.e. resistance to stress corrosion, and thus becomes a new popular material in petrochemical industries. Due to its excellent performation in welding operations, namely smooth wire-feed, stable arc, good weld appearance, few splashes, stable and reliable performance of deposited metal, it is widely used for welding 00Cr22Ni5Mo3N(SUS) steels that are used in petroleum industries.