Abstract: A nitrogen-rich two-phase stainless steel that has corrosion resistance equal to that of standard type of two-phase stainless steel and is not susceptible to corrosion in a welding heat-affected part, wherein the austenite phase area ratio is 40-70%, the PI value expressed by formula (1) is 30-38, the NI value expressed by formula (2) is 100-140, and the ?pre expressed by formula (3) is 1350-1450. (1) PI=Cr+3.3Mo+16N (2) NI=(Cr+Mo)/N.

Abstract: The present invention provides flux cored wire for welding duplex stainless steel which refines the solidified crystal grains for obtaining weld metal superior in toughness and ductility, characterized by containing, as the chemical ingredients included in the steel sheath and flux, by mass % with respect to the mass of the wire as a whole, C: 0.001 to 0.1%, Si: 0.01 to 1.0%, Mn: 2.0 to 6.0%, Cr: 17.0 to 27.0%, Ni: 1.0 to 10.0%, Mo: 0.1 to 3.0%, Al: 0.002 to 0.05%, Mg: 0.0005 to 0.01%, Ti: 0.001 to 0.5%, and N: 0.10 to 0.30%, further limiting P to 0.03% or less and S to 0.01% or less, satisfying 0.73×Cr equivalents?Ni equivalents?4.0 and Ti (mass %)×N (mass %)?0.0004, and having a balance of iron and unavoidable impurities.

Abstract: A nitrogen-rich two-phase stainless steel that has corrosion resistance equal to that of standard type of two-phase stainless steel and is not susceptible to corrosion in a welding heat-affected part, wherein the austenite phase area ratio is 40-70%, the PI value expressed by formula (1) is 30-38, the NI value expressed by formula (2) is 100-140, and the ?pre expressed by formula (3) is 1350-1450. (1) PI=Cr+3.

Abstract: The present invention provides flux cored wire for welding duplex stainless steel which refines the solidified crystal grains for obtaining weld metal superior in toughness and ductility, characterized by containing, as the chemical ingredients included in the steel sheath and flux, by mass % with respect to the mass of the wire as a whole, C: 0.001 to 0.1%, Si: 0.01 to 1.0%, Mn: 2.0 to 6.0%, Cr: 17.0 to 27.0%, Ni: 1.0 to 10.0%, Mo: 0.1 to 3.0%, Al: 0.002 to 0.05%, Mg: 0.0005 to 0.01%, Ti: 0.001 to 0.5%, and N: 0.10 to 0.30%, further limiting P to 0.03% or less and S to 0.01% or less, satisfying 0.73×Cr equivalents?Ni equivalents?4.0 and Ti(mass %)×N(mass %)?0.0004, and having a balance of iron and unavoidable impurities.