| 摘要 |
A high carbon steel sheet 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 ferrite, in the whole steel microstructure is 20% or more and less than 50%, the average grain size dc of the 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 mum, and the average grain size ds of the 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. |
