| abstract |
Provide stainless steel with excellent corrosion resistance and low temperature toughness. Stainless steel contains 15.5% Cr: 15.5 to 18.0% by mass, and contains one or two selected from the group consisting of Mo and W in a range satisfying the formula (1). The matrix structure has a volume ratio of 40 to 80% tempered martensite phase, 10 to 50% ferrite phase, and 1 to 15% austenite phase. When a microstructure image obtained by photographing a matrix structure at a magnification of 100 times is arranged in the xy coordinate system and each pixel of 1024 × 1024 is expressed in gray scale, β defined by the formula (2) is 1.55 or more. is there. 1.0 ≦ Mo + 0.5W ≦ 3.5 (1) Here, Mo and W are the contents of Mo and W expressed in mass%. |