| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-strength hot-rolled steel sheet that has a TS of around 1.8 GPa and stably shows an excellent bending workability, and to provide a method for producing the same. <P>SOLUTION: The high-strength hot-rolled steel sheet excellent in bending workability has a component composition comprising, by mass, 0.42-0.55% C, ≤0.5% Si, ≤0.4% Mn, ≤0.03% P, ≤0.01% S, ≤0.07% Al, ≤0.01% N, 1.8-2.3% V and the balance being Fe and unavoidable impurities, and has a microstructure where a ferritic phase accounts for ≥95% of the area of the entire matrix. VC is dispersed and precipitated in the matrix and the volume ratio of the total volume of VC to the entire matrix is 0.03-0.04. Here, the average thickness t and the average diameter d of VC, determined based on the assumption that VC has a disk shape, satisfy the relation: (t+d)/2<10 nm. <P>COPYRIGHT: (C)2012,JPO&INPIT |
