| 摘要 |
PROBLEM TO BE SOLVED: To provide a stainless steel having a high strength, high toughness and high corrosion resistance, and suitable for spring material, ID blade plate, metallic gasket, etc. SOLUTION: The high strength stainless steel excellent in toughness has a composition consisting of, by mass, <=0.10% C, 1.0-3.0% Si, <=2.0% Mn, 4.0-9.0% Ni, 12.0-18.0% Cr, 1.0-3.5% Cu, 1.0-5.0% Mo, <=0.15% N, C and N in amounts satisfying the relation of C+N>=0.10%, and the balance Fe with impurities inevitably mixing at manufacture. The high strength stainless steel having >=1,800 N/mm2 tensile strength and excellent in toughness can be manufactured by subjecting the steel showing metastable austenitic phase in a solid- solution-heat-treated state to cold working at a cold draft sufficient for forming 30-80% strain induced martensite and then to short-time aging treatment at 300-650 deg.C for 0.5-5 min.
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