| 摘要 |
<p>A high carbon hot-rolled steel sheet containing by mass 0.20-0.48% C, at most 0.1% Si, at most 0.5% Mn, at most 0.03% P, at most 0.01% S, 0.1-0.6% Al, 0.05-0.5% Cr, 0.0005-0.0050% B, and 0.0010-0.0050% Ca, the average amount of N in a surface layer section at a distance of 0.1mm from the surface in the thickness direction of the sheet being at least 0.1%, and the average amount of N at the center in the thickness direction being at most 0.01%, the remainder having a component composition comprising Fe and unavoidable impurities; and having a microstructure comprising a ferrite phase and a carbide, the average particle size of the ferrite phase being 10-20µm and the spheroidization rate of the carbide being at least 90%.</p> |
