| 摘要 |
PURPOSE:To obtain the titled cold rolled steel sheet by limiting the contents of C, N, S, Ti and Nb of a specifically composed dead soft steel added with Ti and Nb in combination and limiting strictly the coiling conditions in hot rolling and the heating and cooling conditions for continuous annealing. CONSTITUTION:The steel contg., by weight, <=0.0050% C, <=1.5% Si, <=1.5% Mn, formula I Ti, formula II Nb, 0.005-0.10% Al, <=0.20% P, <=0.0050% N and <=0.015% S is hot rolled and is coiled at <=490 deg.C. The steel sheet is subjected to cold rolling at >=50% draft and is then subjected to continuous annealing at the heat cycle consisting of holding for >=1sec under 700-850 deg.C holding conditions, then cooling down to <=500 deg.C at >=5 deg.C/s cooling rate. The cold rolled steel sheet for deep drawing having the excellent BH characteristic is thus obtd. without deteriorating the material quality.
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