| 摘要 |
<p>PURPOSE: A steel sheet and a manufacturing method thereof are provided to obtain a complex structure whereby the final microstructure; including ferrite, martensite, and micro precipitates by controlling the alloy components and processing conditions. CONSTITUTION: A method for manufacturing a steel sheet comprises the steps of: reheating a slab panel, which comprises 0.04-0.15 wt% of C, 0.2-1.0 wt% of Si, 1.0-2.5 wt% of Mn, 0.01-0.10 wt% of P, 0.001-0.010 wt% of S, 0.05-1.00 wt% of Al, 0.03-0.09 wt% of Nb, 0.01-0.09 wt% of V, 0.001-0.006 wt% of B, and the remaining amount of Fe and inevitable impurities(S110), hot rolling the reheated panel(S120), and cooling and coiling the hot rolled panel at a CT(Coiling Temperature) of 550-650°C(S130). [Reference numerals] (AA) Start; (BB) End; (S110) Reheating slab(SRT: 1150-1250°C); (S120) Hot rolling(FDT: 850-950°C); (S130) Cooling/coiling(CT: 550-650°C)</p> |
