DUPLEX STAINLESS STEEL WELD STRUCTURE FOR OXIDIZABLE FLUID ENVIRONMENT, AND DUPLEX STAINLESS STEEL FOR DUPLEX STAINLESS STEEL WELD STRUCTURE FOR OXIDIZABLE FLUID ENVIRONMENT

摘要

To provide a duplex stainless steel weld structure having excellent corrosion resistance in an environment of a fluid containing oxidative substances represented by ozone.SOLUTION: There is provided a duplex stainless steel weld structure for oxidative fluid environment having a material to be welded consisting of a base material part and a weld heat affected part, and weld metal, in which a chemical component of the material to be welded contains C:0.10% or less, Si:0.01 to 5.0%, Mn:0.01 to 8.00%, P:0.10% or less, S:0.050% or less, Ni:1.0 to 8.0%, Cr:20.0 to 30.0% and N:0.05 to 0.50% and the balance Fe with inevitable impurities, ferrite phase percentage of the weld metal is 35.0 to 65.0 area%, PREN of the formula (1) of the weld metal is 0.90 times or more of PREN of the (1) formula of the material to be welded, average width of the weld heat affected part is 200.0 μm or more, average particle diameter of the ferrite phase of the weld heat affected part is 200.0 μm or less. PREN=Cr+3.3Mo+16 N (1).SELECTED DRAWING: None