| 摘要 |
PROBLEM TO BE SOLVED: To produce a BH steel sheet in which cold aging is suppressed while the content of BH is stably secured and moreover free from problems caused by nitrides such as the variation of the material in a coil and the reduction of formability. SOLUTION: This cold rolled steel sheet has a composition containing, by weight, 0.0010 to 0.0025% C, <=0.05% Si, 0.36 to 0.8% Mn, 0.01 to 0.08% P, 0.003 to 0.02% S, 0.03 to 0.1% sol.Al, 0.003 to 0.02% Nb, <=0.0015% N, and the balance Fe with inevitable impurities and also satisfying Nb<=93/12C.
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