| 摘要 |
<p>PURPOSE: A steel sheet having an excellent sulfuric acid-hydrochloric acid composite corrosion resistance and weldability, and a manufacturing method thereof are provided to minimize the number of surface defects due to Cu added to improvie corrosion resistance, thereby improving weldability. CONSTITUTION: A steel sheet having an excellent sulfuric acid-hydrochloric acid composite corrosion resistance and weldability includes less than 0.15 wt% of C, 0.2 to 1.0 wt% of Si, 0.5 to 1.5 wt% of Mn, less than 0.002 wt% of P, less than 0.02 wt% of S, 0.01 to 0.1 wt% of Al, 0.2 to 1.0 wt% of Cu, 0.1 to 0.5 wt% of Ni, 0.03 to 0.1 wt% of Co, 0.05 to 0.15 wt% of Sb, remnant Fe, and other inevitable impurities. Cu and Ni satisfy 0.4<=Ni/Cu<=0.7. Sb, Co and Cu satisfy 0.2<=(Sb/122+Co/59)/(Cu/64)<=1.0. Co and Sb satisfy 1<=(Co/59)/(Sb/122)<=3. A manufacturing method of the steel sheet having an excellent sulfuric acid-hydrochloric acid composite corrosion resistance and weldability comprises: a step of reheating steel slab at a temperature of more than 1200°C; a step of finish-rolling the reheated steel slab at a temperature of more than 900°C; and a step of winding the finish-rolled steel sheet at a temperature of more than 600°C.</p> |
