| 摘要 |
<p>THERE ARE PROVIDED A COLD ROLLED STEEL HAVING EXCELLENT FORMABILITY, SHAPE FIXABILITY AND PRACTICAL MANUFACTURING STABILITY, AND A METHOD FOR MANUFACTURING THE STEEL SHEET. THE CHEMICAL COMPOSITION OF THE COLD ROLLED STEEL SHEET IS, BY MASS%, C: 0.0010% OR MORE AND 0.0030% OR LESS, SI: 0.05% OR LESS, MN: 0.1% OR MORE AND 0.3% OR LESS, P: 0.05% OR LESS, S: 0.02% OR LESS, A1: 0.02% OR MORE AND 0.10% OR LESS, N: 0.005% OR LESS, NB: 0.010% OR MORE AND 0.030% OR LESS, B: SATISFYING THE RELATIONSHIP 0.0010% ? B-11/14XN ? 0.0050%, AND THE BALANCE BEING FE AND INEVITABLE IMPURITIES. THE MEAN ELONGATION (E1m) IS 42% OR MORE AND A MEAN LANKFORD VALUE (Rm) IS 1.2 OR MORE AND 1.6 OR LESS. THE STEEL SHEET CAN BE STABLY MANUFACTURED WITHOUT PRECISE CONTROL OF SOAKING TEMPERATURE BY ANNEALING AFTER COLD ROLLING AT A SOAKING TEMPERATURE OF A TEMPERATURE DEPENDING ON ROLLING REDUCTION CR (%), NB CONTENT (PPM BY MASS) AND B CONTENT (PPM BY MASS) AND DETERMINED BY USING (820+NB/15+B-CR) OR HIGHER AND 860°C OR LOWER FOR A HOLDING TIME OF 30 OR MORE AND 200 OR LESS SECONDS.</p> |
