HIGH-STRENGTH COLD-ROLLED STEEL SHEET WITH EXCELLENT WORKABILITY AND COLOR FASTNESS AND A MANUFACTURING METHOD THEREOF WHICH OPTIMIZES ANNEALING AND COOLING CONDITIONS TO OBTAIN STRENGTH AND DUCTILITY

摘要

PURPOSE: A high-strength cold-rolled steel sheet and a manufacturing method thereof are provided to improve color fastness at high temperatures and aging resistance at room temperature by adding Sn to form a Sn-based oxide layer on the surface of the steel sheet.;CONSTITUTION: A high-strength cold-rolled steel sheet comprises 0.0005-0.0020wt.% of C, 0.05-0.35wt.% of Sn, 0.3-0.6wt.% of Mn, 0.03-0.08wt.% of P, 0.01-0.10wt.% of Al, W 0.05-0.30wt.% of Al, 0.001-0.004wt.% of N, 0.015wt.% or less of S, and the remaining amount of Fe and inevitable impurities. A Sn-based oxide layer including Sn2O3 is formed on the surface of the cold-rolled steel sheet.;COPYRIGHT KIPO 2013