| 摘要 |
Provided is a high-carbon hot-rolled steel sheet whose raw material is a B-containing steel, with which excellent hardenability is stably achieved even if annealing is performed in a nitrogen atmosphere, and which has excellent workability corresponding to a hardness of 65 or less in terms of HRB and a total elongation El of 40% or more before a quenching treatment is performed. A high-carbon hot-rolled steel sheet having a chemical composition containing, by mass%, C: 0.20% or more and 0.48% or less, Si: 0.10% or less, Mn: 0.50% or less, P: 0.03% or less, S: 0.010% or less, sol.Al: 0.10% or less, N: 0.0050% or less, B: 0.0005% or more and 0.0050% or less, one or more of Sb, Sn, Bi, Ge, Te, and Se in an amount of 0.002% or more and 0.030% or less in total, and a microstructure including ferrite and cementite and having a density of cementite in ferrite grains of 0.10 pieces/µm 2 or less. |
