| 摘要 |
A method of manufacturing a cold-rolled steel sheet having a good deep drawability is disclosed, wherein a hot rolled steel sheet having a composition of C</=0.0035%, Si</=1.0%, Mn</=1.0%, Al:0.005-0.10%, P</=0.15%, N</=0.0035%, S</=0.015%, Ti: (48/14N(%)+48/32S(%)) or {4x(C(%)+N(%))} DIFFERENCE (3.48/12C(%)+48/14N(%)+48/32S(%)) and Nb: (0.2.93/12C(%)) DIFFERENCE (93/12C(%))% is cooled within 2 seconds after the completion of finisher rolling and then at an average cooling rate of not less than 10 DEG C./sec until it arrives at a coiling step, and then the cooled steel sheet is coiled at a temperature of not more than 710 DEG C., subjected to a cold rolling at a reduction of not less than 50%, which was subjected to a continuous annealing in a heatcycle inclusive of heating from 400 DEG C. to 600 DEG C. at a heating rate of not less than 5 DEG C./sec and soaking at a temperature range of 700 DEG C.-Ac3 point for 1 second or more. |
