| 摘要 |
PURPOSE:To manufacture inexpensively a cold rolled steel sheet for working having good aging resistance by hot rolling a steel contg. a specified compsn. of C, Mn, Al, N, Ti, then cooling rapidly and winding said material at low temp. and cold rolling, further annealing continuously under a suitable condition. CONSTITUTION:The steel consisting of 0.01-0.10wt% C, 0.02-0.40% Mn, 0.001- 0.08% Sol, Al, 0.001-0.007% N, 0.002-0.020% Ti, if necessary, further one kind or more among 0.05-0.5% Si, 0.03-0.11% P, 0.0002-0.0010% B, while satisfying next relation: -0.001%<N-14/48Ti<0.001% in contents of N and Ti, and the balance Fe with inevitable impurities is hot rolled, then said mateial is cooled rapidly, and wound to coil state at <=270 deg.C temp. Next, the hot rolled plate is cold rolled by >=50% reduction ratio, then further annealed continuously at 1-100 deg.C/sec heating rate, 650-850 deg.C homogenizing temp. to obtain stably, uniformly and inexpensively the cold rolled steel sheet for working having good aging resistance and gamma value. |
