| 摘要 |
Provided is a cold-rolled steel plate having excellent moldability and shape retention, and outstanding production stability using actual machinery. Also provided is a method for producing same. The composition contains 0.0010 to 0.0030% C, no more than 0.05% C, 0.1 to 0.3% Mn, no more than 0.05% P, no more than 0.02% S, 0.02 to 0.10% Al, no more than 0.005% N, 0.010 to 0.030% Nb, and 0.0010 ?B-11/14×N?0.0050% B, with the remainder made up of iron and inevitable impurities. The average total elongation (Elm) is at least 42%, and average r value (rm) is 1.2 to 1.6. By maintaining post cold-rolling annealing for 30 to 200 sec. at a holding temperature of (820+Nb/15+B-CR) to 860°C according to compression rate CR(%), Nb content (mass ppm) and B content (mass ppm), it is possible to manufacture the cold-rolled steel plate using actual machinery in a stable manner, without pinpoint control of the holding temperature. |
