| 摘要 |
A high carbon steel sheet characterized by having a chemical composition containing C: 0.20% to 0.50%, Si: 1.0% or less, Mn: 2.0% or less, P: 0.03% or less, S: 0.02% or less, sol. Al: 0.08% or less, N: 0.02% or less, and the remainder composed of Fe and incidental impurities, on a percent by mass basis, and a microstructure composed of ferrite and cementite, wherein the fraction of pro-eutectoid ferrite, among the above-described ferrite, in the whole steel microstructure is 20% or more and less than 50%, the average grain size dc of the above-described cementite in the region from the position at one-quarter of the sheet thickness of the steel sheet to the sheet thickness center is 0.50 to 1.5 µm, and the average grain size ds of the above-described cementite in the region from the surface of the steel sheet to the position at one-quarter of the sheet thickness satisfies ds/dc ‰¤ 0.8. |
