| 摘要 |
Disclosed are a hot-rolled steel sheet and a manufacturing method thereof, wherein the hot-rolled steel sheet with high strength can have an improved impact property by adding Nb, Bi, and Mo. The manufacturing method of the hot-rolled steel sheet according to the present invention comprises: a step of hot-rolling a slab sheet; and a step of cooling and coiling the hot-rolled sheet, wherein the slab sheet comprises 0.12 to 0.14 wt% of C, at most 0.15 wt% of Si, 1.4 to 1.6 wt% of Mn, at most 0.015 wt% of P, at most 0.003 wt% of S, 0.001 to 0.004 wt % of Ca, 0.01 to 0.05 wt% of Nb, 0.01 to 0.20 wt% of Bi, 0.01 to 0.20 wt% of Mo, and remnants consist of Fe and inevitable impurities. [Reference numerals] (AA) Start; (BB) End; (S105) Reheat a slab (SRT: 1150 to 1300°C); (S110) Hot-roll (FDT: 820 to 860°C); (S120) Cool/coil (CT: 520 to 580°C) |
