Patent ID: 6749701
Filing Date: 2004-06-15
Classification: C21D,C22C

Abstract:
A method of inhibiting cold-rolled steel sheet edge cracking of a high-strength, high-toughness martensitic stainless steel sheet, which method is applied with respect to a hot-rolled steel sheet of martensitic stainless steel having a chemical composition comprising, in mass percent,more than 0.03 to 0.15% of C, 0.2-2.0% of Si, not more than 1.0% of Mn, not more than 0.06% of P, not more than 0.006% of S, 2.0-5.0% of Ni, 14.0-17.0% of Cr, more than 0.03 to 0.10% of N, 0.0010-0.0070% of B, and the balance of Fe and unavoidable impurities and having an A value defined by Equation (1) of not less than âˆ’1.8: A value=30(C+N)âˆ’1.5Si+0.5Mn+Niâˆ’1.3Cr+11.8â€ƒâ€ƒ(1), â€ƒand comprises a step of subjecting the sheet to a single cycle or multiple repeated cycles of a process (intermediate annealing and cold rolling process) consisting of intermediate-annealing the sheet at a soaking temperature of 600-800Â° C. for a soaking period of not more than 10 hr to adjust steel hardness to Vickers hardness (Hv) of not greater than 380, followed by cold rolling.