High-strength hot rolled steel sheet and its manufacturing method

摘要

A high-strength hot-rolled steel sheet having excellent elongation flange formability, bending formability and low-temperature toughness while maintaining high strength of 1180 MPa or more of tensile strength TS, and a manufacturing method thereof are provided. A specific component composition and a total area ratio of 90% or more of the lower bainite phase and/or tempered martensite phase as the main phase, and the average particle diameter of the column phase is 10.0 µm or less, and the amount of Fe in the Fe-based precipitate is mass% A high-strength hot-rolled steel sheet having a steel structure of 0.70% or less, a surface arithmetic mean roughness (Ra) of 2.50 μm or less, and a tensile strength TS of 1180 MPa or more.