Patent ID: 11473177

Abstract:
The steel material according to the present disclosure has a chemical composition consisting of, in mass %, C: 0.10 to 0.60%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.025% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, Cr: 0.20 to 1.50%, Mo: 0.25 to 1.50%, V: 0.01 to 0.60%, Ti: 0.002 to 0.050%, B: 0.0001 to 0.0050%, N: 0.0020 to 0.0100%, and O: 0.0100% or less, with the balance being Fe and impurities. A dislocation density ρ is 3.5×1015 m−2 or less. Among fine precipitates, the numerical proportion of precipitates for which a ratio of the Mo content is not more than 50% is 15% or more. The yield strength is in a range of 655 to 1172 MPa.