Patent ID: 8157930
Filing Date: 2012-04-17
Classification: C22C

Abstract:
1. A martensitic stainless steel consisting of C: 0.02-0.09%, Si: 0.05-1.0%, Mn: 0.05-0.95%, P: not more than 0.03%, S: not more than 0.01%, Cr: 9-15%, Ni: 1.0-4.5%, Al: not more than 0.05%, N: not more than 0.1%, Cu: 0.05-5%, and Mo: 0.05-5% in mass %, the residual being Fe and impurities, wherein the contents of Cu and Mo satisfy the following formula (a), and wherein the hardness is 30-45 in HRC and the amount of carbides in grain boundaries of prior austenite is not more than 0.13 volume %, a yield strength of the steel after cooling by quenching or air cooling in a final treatment after final heating at a temperature of the Ac 3 point or more is not less than 815 MPa.