| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hot rolled steel sheet having excellent hole expansibility while increasing its strength. <P>SOLUTION: The steel sheet has a composition comprising, by mass, 0.01 to 0.1% C, 0.01 to 2.0% Si, 0.05 to 3.0% Mn, ≤0.1% P, ≤0.03% S, 0.005 to 0.02% Al, ≤0.005% N, 0.0005 to 0.003% Ca, ≤0.01% Nb, 0.005 to 0.3% Ti and 0.01 to 0.1% V, and the balance Fe with inevitable impurities, whose microstructure is composed of a ferritic structure, a bainitic structure or their mixed structure, and also, the random intensity ratio of the ä211} plane parallel to the rolling face is ≤2.0. <P>COPYRIGHT: (C)2010,JPO&INPIT |
