| 摘要 |
PURPOSE:To manufacture a high strength cold rolled steel plate superior in cold workability by hot rolling a steel ingot containing the specified amount of composition of C, Si, Mn etc. under a suitable condition, and successively performing the cooling, winding, and a treatment of box annealing etc. after a cold rolling. CONSTITUTION:The steel ingot consists of <=0.15% C, <=3% Si, <=2% Mn, 0.5- 4.5% Si+Mn and if necessary, furthermore contains >=one kind among 0.03- 0.13% P, 0.2-0.8% Cu and/or >=one kind among 0.01-0.2% Ti, 0.01-0.1% Nb, 0.01-0.1% V, 0.01-0.2% Zr and the balance Fe with impurities. The steel ingot is hot rolled at a finishing temp. higher than Ar3 transformation point, and cooled at a rate >=30 deg.C/sec, wound at >=650 deg.C, pickled and cold rolled. Then the box annealing for soaking is performed at the heating rate about <=150 deg.C/hr and in the temp. range of 650-800 deg.C. |
