| 摘要 |
PROBLEM TO BE SOLVED: To improve the deformation strength characteristic of members and parts during press forming by providing a composition which consists of C, Si, Mn, P, S, Al, N, Mo, one or more elements among Cr, Nb, Ti, V, and B, and the balance Fe with inevitable impurities and in which the contents of these elements satisfy a specific relation. SOLUTION: The steel sheet has a composition which contains, by weight, 0.01-0.20% C, 0.01-3.0% Si, 0.01-3.0% Mn, 0.002-0.2% P, 0.001-0.020% S, 0.005-2.0% Al, 0.0002-0.01% N, and 0.01-1.5% Mo and further contains one or more kinds among 0.01-1.5% Cr, 0.005-0.10% Nb, 0.005-0.10% Ti, 0.005-0.10% V, and 0.0003-0.005% B and in which respective contents of these elements satisfy the relation represented by inequality. Moreover, it is preferable that the dislocation density of this steel sheet is 50 to 1000 perμm2 of field of view of a microscope, and thereby the strength at warm forming can be increased to a greater extent.
|
