| 摘要 |
The present invention relates to a hot-rolled steel sheet having excellent multi-corrosion resistant in comparison with steels containing copper and sulfuric acid in which defective surface caused by copper is not generated or sulfuric acid-hydrochloric acid multi-corrosion resistant and weldability and a manufacturing method thereof. The hot-rolled steel sheet contains 0.01-0.1 wt% of C, 0.5-1.5 wt% of Si, 0.5-1.5 wt% of Mn, 0.1-0.2 wt% of Al, 0.2-1.0 wt% of Cu, 0.1-0.5 wt% of Ni, 0.03-0.1 wt% of Co, 0.05-0.15 wt% of Sb, less than 0.02 wt% of S, less than 0.02 wt% of P, the remainder of Fe, and impurities. The ratio of Ni and Cu exceeds 0.4 and less than 0.7. In a multi-corrosion process, an oxide layer containing the oxide of CuO and Al2O3 is formed. |
