| 摘要 |
PURPOSE: A hot-rolled steel sheet and a manufacturing method thereof are provided to facilitate secondary working by reducing the strength. CONSTITUTION: A hot-rolled steel sheet comprises 0.45-0.55wt.% of C, 0.65-0.95wt.% of Mn, 0.15-0.35wt.% of Si, 0.02wt.% or less(0 is exclusive) of P, 0.02wt.% or less(0 is exclusive) of S, 0.001-0.030wt.% of Al, 0.80-1.10wt.% of Cr, 0.40-0.60wt.% of Mo, 0.15-0.25wt.% of V, 0.007wt.% or less(0 is exclusive) of N, and the remaining amount of Fe and inevitable impurities. The hot-rolled steel sheet has a pearlite fraction of 60-70% and a ferrite fraction of 30-40%. |
