COLD-ROLLED STEEL SHEET AND PROCESS FOR PRODUCING THE SAME

摘要

A cold-rolled steel sheet which contains up to 0.0030% C, up to 0.02% Si, 0.15-0.19% Mn, up to 0.020% P, up to 0.015% S, up to 0.0040% N, and 0.020-0.070% Al, contains Nb in such an amount that 1.00 = Nb/C (atomic equivalent ratio) = 5.0, and contains B in such an amount that 1 ppm = B-(11/14)N = 15 ppm (wherein B and N are the contents of the respective elements), with the remainder being iron and unavoidable impurities. The steel sheet has an r-value in-plane anisotropy (?r) of -0.10= r=0.10. It is suitable for use in producing cell cans and has reduced anisotropy. In producing the steel sheet, cold rolling is conducted especially at a rolling ratio of 70-87% and then annealing is conducted on a continuous annealing line at an annealing temperature of from the recrystallization temperature to 830°C.