| 摘要 |
Provided are: a high-tensile-strength hot-rolled steel sheet provided with both high strength and favorable workability (stretch flangeability), and moreover has superior material uniformity; and a method for producing same. The hot-rolled steel sheet has a tensile strength of at least 780 MPa, and has: a composition containing, by mass%, at least 0.03% and less than 0.07% of C, no greater than 0.3% of Si, 0.5-2.0% inclusive of Mn, no greater than 0.025% of P, no greater than 0.005% of S, no greater than 0.0060% of N, no greater than 0.1% of Al, 0.07-0.11% inclusive of Ti, and at least 0.08% and less than 0.15% of V in a manner such that Ti and V satisfy 0.18 <= Ti + V <= 0.24 (Ti and V being the amount contained (mass%) of the respective elements), the remainder comprising Fe and unavoidable impurities; a matrix such that the area ratio of ferrite phase with respect to the total structure is at least 95%; and a structure such that minute carbides containing Ti and V and having an average grain size of less than 10 nm are dispersed/precipitated, and the volume ratio of the minute carbides with respect to the total structure is at least 0.0020. |
