| 摘要 |
<p>PURPOSE: A high-strength cold-rolled steel sheet and a manufacturing method thereof are provided to obtain improved press-formability and galvanizing characteristic by controlling the contents of aluminum, titanium, and chrome to improve the coefficient of plastic anisotropy and elongation ratio. CONSTITUTION: A high-strength cold-rolled steel sheet manufacturing method comprises the steps of: reheating a slab(S110), finishing hot-rolling the slab at an FDT(Finishing Delivery Temperature) of 840-920°C(S120), cooling and coiling the hot-rolled sheet at a CT(Coiling Temperature) of 530-600°C(S130), pickling the coiled sheet(S140), cold-rolling the pickled sheet at a reduction rate of 50-70%(S150), annealing the cold-rolled sheet(S160), and cooling the annealed sheet(S170). [Reference numerals] (AA) Start; (BB) End; (S110) Slab reheating(SRT: 1220-1300°C); (S120) Hot rolling(FDT: Ar3-Ar3+40°C); (S130) Cooling/coiling(CT: 530-600°C); (S140) Pickling; (S150) Cold rolling(Reduction ratio: 50-70%); (S160) Annealing(AT: 780-840°C); (S170) Cooling(5-20°C/sec, 500-600°C); (S180) Alloying(460-520°C)</p> |
