| 摘要 |
PROBLEM TO BE SOLVED: To provide a martensitic stainless steel sheet having high strength, toughness and spring characteristics and to provide a method for suppressing its edge cutting caused by cold rolling. SOLUTION: This steel sheet has a composition containing, by mass, >0.03 to 0.15% C, 0.2 to 2.0% Si, <=1.0% Mn, <=0.06% P, <=0.006% S, 2.0 to 5.0% Ni, 14.0 to 17.0% Cr, >0.03 to 0.10% N and 0.0010 to 0.0070% B, and the rest composed of Fe with inevitable impurities, and has A value = 30(C+N)-1.5Si+0.5Mn+Ni-1.3Cr+11.8 of >=-1.8. In use for a metal gasget, the steel sheet has particularly a martensitic phase of >=85 vol., and its spring limit value after the application of tensile strain of 0.1%, i.e., Kb0.1 is >=700 N/mm2. Moreover, the hot rolled steels sheet is subjected to intermediate annealing of 600 to 800 deg.C×<=10 soaking to control the hardness of the material to <=380 Hv, and, after that, cold rolling is performed to suppress edge cutting caused by cold rolling.
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