| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength cold rolled steel sheet for deep drawing, combining drawability, strength, and resistance to secondary working brittleness and used for automobile members or the like. SOLUTION: This steel sheet has a composition containing, by mass, 0.0010-0.0040% C, <=1.0% Si, 0.5-2.0% Mn, 0.03-0.12% P, <=0.02% S, 0.01-0.10% Al, <=0.004% N, 0.015-0.060% Ti, 0.005-0.040% Nb, and 0.0003-0.0020% B, also containing respective elements satisfying inequalities C<= Ti-(48/14)N+(48/93) Nb}/10, 0.05×Mn-0.02<=P<=0.1×Mn+0.02, and 0.5×Ti-0.01<=Nb<=0.5×Ti+0.02, and having the balance Fe with inevitable impurities. Each symbol of element in the inequalities represents its content (%).
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