| 摘要 |
<p>Disclosed is a steel material which can be sufficiently quenched by short time heating at low temperatures and is capable of providing a high strength molded article. The steel material is suitable as a material for hot pressing or hot three-dimensional bending. Specifically, the steel material has a chemical composition that contains, in mass%, 0.05-0.35% of C, 0.5% or less of Si, 0.5-2.5% of Mn, 0.03% or less of P, 0.01% or less of S, 0.1% or less of sol. Al, 0.01% or less of N, and if necessary, one or more elements selected from the group consisting of 0.0001-0.005% of B, 0.01-0.1% of Ti, 0.18-0.5% of Cr, 0.03-0.1% of Nb, 0.18-1.0% of Ni and 0.03-0.5% of Mo, and has a steel structure wherein the spheroidization ratio of carbides is 0.60-0.90.</p> |
