Steel sheet

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A steel sheet includes, as a chemical composition, by mass % : C : 0.05-0.30%; Si : 0.2-2.0%; Mn : 2.0-4.0%; Al : 0.001-2.000%; P : 0.100% or less; S : 0.010% or less; N : 0.010% or less; Ti : 0-0.100%; Nb : 0-0.100%; V : 0-0.100%; Cu : 0-1.00%; Ni : 0-1.00%; Mo : 0-1.00%; Cr : 0-1.00%; W : 0-0.005%; Ca : 0-0.005%; Mg : 0-0.005%; a rare earth element (REM) : 0-0.010%; B : 0-0.0030%; and a remainder of Fe and impurities, in which a metallographic structure contains, by area ratio, 95% or more of a hard structure and 0-5% 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.