| 摘要 |
PURPOSE:To perform the titled manufacture, by applying hot finish rolling, winding and pickling of steel slab having a specified compsn. under specified conditions, further applying primary cold rolling, primary annealing, secondary cold rolling, secondary annealing in order under specified conditions. CONSTITUTION:Steel slab composed of, by weight 0.01-0.08% C, 0.03-0.25% Mn, 0.001-0.015% S, 0.02-0.07% Al, 0.002-0.007% N, 0.0010-0.0050% O and the balance iron with inevitable impurity is hot finishing rolled at >=Ar3 point finishing temp., the plate is cooled by <= about 20 deg.C/sec rate and wound up at 500-600 deg.C. Next, the sheet is pickled, then primarily cold rolled by 45-85% draft, then decarburization annealed by primarily annealing at 650- about 800 deg.C so that C quantity becomes <=0.006%. Further, the sheet is secondarily cold rolled by 60-85% draft and heated at a low speed of 20-40 deg.C/hr to carry out secondary annealing.
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