| 摘要 |
PROBLEM TO BE SOLVED: To provide a welded joint having high pitting corrosion resistance.SOLUTION: There is provided a two-phase stainless steel welded joint in which each of a base metal and a weld metal has a chemical composition containing, by mass%, C:0.03% or less, Si:0.5% or less, Mn:2% or less, P:0.04% or less, S:0.003% or less, Cr:21 to 29%, Ni:4.0 to 10.5%, Mo:0.8 to 4.0%, N:0.1 to 0.4%, sol.Al:0.040% or less, W:0 to 4.0%, Cu:0 to 4.0%, B:0 to 0.005%, REM:0 to 0.2% and the balance Fe with inevitable impurities and in which an austenite index a represented by the formula (1) is 0.1 to 0.4, Mn/N≥2, a PF index represented by the formula (2) is 1.0 or less, and thickness of an oxidized scale of the surfaces of the base metal and the weld metal upon welding is 500 nm or less. a={Ni+30(C+N)-0.6(Cr+1.5Si+Mo)+5.6}/{Cr+1.5Si+Mo-6}(1) PF=Mn×(100 Pb+50Sb+30Zn+40As)(2) |
