| 摘要 |
A high strength hot rolled steel sheet having a tensile strength TS of 980 MPa or more, has a composition containing, on a percent by mass basis, C: 0.05% or more and 0.18% or less, Si: 1.0% or less, Mn: 1.0% or more and 3.5% or less, P: 0.04% or less, S: 0.006% or less, Al: 0.10% or less, N: 0.008% or less, Ti: 0.05% or more and 0.20% or less, V: more than 0.1% and 0.3% or less, and the balance being Fe and incidental impurities, and has a microstructure comprising a primary phase and a secondary phase, the primary phase being a bainite phase having an area fraction of more than 85%, the secondary phase being at least one of ferrite phase, martensite phase, and retained austenite phase, the secondary phase having an area fraction of 0% or more and less than 15% in total,the bainite phase having an average lath interval of laths of 400 nm or less, and the laths having an average long axis length of 5.0 µm or less. |
