| abstract |
A kind of high-carbon hot-rolled steel sheet, it has following one-tenth and is grouped into: in quality %, contain C:0.20～0.48%, below Si:0.1%, below Mn:0.5%, below P:0.03%, below S:0.01%, Al:0.1～0.6%, Cr:0.05～0.5%, B:0.0005～0.0050%, Ca:0.0010～0.0050%, the average N amount that enters the skin section of 0.1mm along thickness of slab direction from surface is more than 0.1%, the average N amount of thickness of slab central portion is below 0.01%, surplus is made up of Fe and inevitable impurity, and there is following microscopic structure: formed by ferritic phase and carbide, the average grain diameter of ferritic phase is 10～20 μ m, the nodularization rate of described carbide is more than 90%. |