简介 |
A steel sheet includes, as a chemical composition, by mass% : C : 0.05% to 0.30%; Si : 0.2% to 2.0%; Mn : 2.0% to 4.0%; Al : 0.001% to 2.000%; P : 0.100% or less; S : 0.010% or less; N : 0.010% or less; Ti : 0% to 0.100%; Nb : 0% to 0.100%; V : 0% to 0.100%; Cu : 0% to 1.00%; Ni : 0% to 1.00%; Mo : 0% to 1.00%; Cr : 0% to 1.00%; W : 0% to 0.005%; Ca : 0% to 0.005%; Mg : 0% to 0.005%; a rare earth element (REM) : 0% to 0.010%; B : 0% to 0.0030%; and a remainder of Fe and impurities, in which a metallographic structure contains, by area ratio, 95% or more of a hard structure and 0% to 5% of residual austenite, by mass% in a cross section in a thickness direction, C1/C2 which is a ratio of an upper limit C1 of a Mn content to a lower limit C2 of the Mn content is 1.5 or less, and a bake-hardening amount BH is 150 MPa or less. |