Method for producing cold rolled steel sheets having a noticeably excellent formability

Abstract From the Canadian patent

Non-ageing cold rolled steel sheets having a very excellent formability are produced by hot rolling a steel consisting of not more than 0.008% of C not more, than 0.20% of Si, 0.04-0.30% of Mn not more than 0.03%, of P, 0.01-0.10% of A? a content of A? being more than, N%x4, not more than 0.02% of S not more than 0.01% of N, 0.01-0.07% of Nb a content of Nb being C%x3-{co/ox8+0.02}% and the remainder being substantially Fe at a total, reduction of not less than 90% a rolling speed of not, less than 40 m/min in the finishing rolling and a finishing temperature of not lower than 830°C, coiling the hot rolled strip at a temperature of 600-800°C cold rolling, the coiled strip in a conventional …