| 摘要 |
PURPOSE:To produce inexpensively a cold rolled steel sheet having good press formability at high efficiency by coiling a thin casting billet having a specific compsn. contg. C, Mn, sol.Al, N and Ti, etc. at a specific temp. then subjecting the same to cold rolling and recrystallization annealing. CONSTITUTION:A molten steel having the component compsn. which contains 0.001-0.015wt% C, 0.01-1.20% Mn, <=0.10% sol.Al, <=0.0060% N, and >=1 kind among <=0.20% Ti, <=0.20% Nb and <=0.20% Zr, contains, if necessary, >=1 kind among 0.01-0.20% V, 0.03-0.10% P, 0.05-1.00% Cr, 0.03-0.20% rare earth element, 0.0003-0.0040% B, and 0.10-2.00% Si, satisfies the component relation expressed by the formula and consists of the balance Fe and unavoidable impurities is quickly cooled and is cast continuously to a thin casting billet. The billet is then coiled at 500-800 deg.C and the coil is subjected to cold rolling and recrystallization annealing, by which the cold rolled steel sheet having good surface skin texture and press formability is obtd.
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