| 摘要 |
Disclosed are a high-strength cold-rolled steel sheet, which has excellent low-temperature impact toughness and bending properties, and a manufacturing method thereof. The manufacturing method of the high-strength cold-rolled steel sheet comprises: a step (a) of cold-rolling a hot-rolled steel sheet comprising 0.2 wt% of C, 1.0-1.5 wt% of Si, 1.5-2.0 wt% of Mn, 0.015-0.030 wt% of P, less than or equal to 0.003 wt% of S, 0.01-0.05 wt% of Al, less than or equal to 0.002 wt% of B, and the remainder consisting of Fe and inevitable impurities; a step (b) of annealing the cold-rolled steel sheet in a single phase austenite section having a temperature of Ac3 point + 10°C to Ac3 point + 100°C; a step (c) of cooling the annealed steel sheet to a temperature of right above Ms; and a step (d) of tempering the cooled steel sheet at a temperature of right above Ms to right above Ms + 100°C. |
