| 摘要 |
This high-strength rolled steel sheet has a component composition containing, by mass, 0.15 to 0.30% of C, 1.0 to 3.0% of Si, 0.1 to 5.0% of Mn, 0.1% or less of P (not including 0%), 0.010% or less of S (not including 0%), 0.01% or less of N (not including 0%), and 0.001 to 0.10% of Al, with the remainder being made up by iron and unavoidable impurities, martensite being contained at 95% or above by area ratio, the total area ratio of residual austenite and ferrite being 5% or less (including 0%), the average size of carbides being no greater than 60 nm in terms of equivalent circle diameter, and the number density of carbides having an equivalent circle diameter of at least 25 nm being no greater than 5.0 × 10 5 per 1 mm 2 . The high-strength rolled steel sheet has a yield strength of at least 1180 MPa and a tensile strength of at least 1470 MPa. |
