MARTENSITIC STAINLESS-STEEL SHEET AND METAL GASKET

摘要

Provided is a martensitic stainless-steel sheet having a reduced anisotropy in workability and fatigue resistance which are attributable to oxide based inclusions. A martensitic stainless-steel sheet which has a steel composition that contains, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and unavoidable impurities, and that has a value of γmax, determined by the following equation (1), of 80.0 or greater, and in which oxide based inclusions are observed in the metallographic structure, the oxide based inclusions having a converted composition comprising up to 30 mass % or less Al2O3, 20 to 60 mass % SiO2, and 15 to 70 mass % MnO.

主权项

1. A martensitic stainless hot-rolled steel sheet having a steel composition that comprises, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and inevitable impurities, and that has a value of γmax, which is determined by a following equation (1), of 80.0 or greater, and in which an average composition of oxide based inclusions observed in a metallographic structure has 30 mass % or less Al2O3, 20 to 60 mass % SiO2 and 15 to 70 mass % MnO in terms of mass ratio conversion of Al2O3, SiO2 and MnO:
γmax=420C−11.5Si+7Mn+23Ni−11.5Cr−49(Ti+Nb+V)−52Al+470N+189   (1) herein, a place of the element symbol in the equation (1) is assigned with a content of the corresponding element denoted in terms of mass %.