Hot-rolled steel sheet for tailored rolled blank and tailored rolled blank

Abstract

A hot-rolled steel sheet for a tailored rolled blank is provided that has high tensile strength and is excellent in cold formability. The hot-rolled steel sheet has: a chemical composition that contains, in mass %, C, Si, Mn, P, S, Al, N and Ti, with the balance being Fe and impurities, and that satisfies Formula (1); and a microstructure containing, in terms of area ratio, 20% or more of bainite, wherein 50% or more in terms of area ratio of the balance is ferrite. In the interior of the hot-rolled steel sheet an average value of pole densities of an orientation group {100}<011> to {223}<110> is 4 or less, and a pole density of a {332}<113> crystal orientation is 4.8 or less. In an outer layer of the hot-rolled steel sheet, a pole density of a {110}<001> crystal orientation is 2.5 or more. Furthermore, among Ti carbo-nitrides in the hot-rolled steel sheet, the number density of fine Ti carbo-nitrides having a particle diameter of 10 nm or less is 1.0×1017 per cm3 or less, and a bake hardening amount is 15 MPa or more, [Ti]−48/14×[N]−48/32×[S]≥0  (1).

Dependencies are inferred from the claim text.