| 摘要 |
PURPOSE:To obtain a titled black plate having excellent shapes at considerably reduce energy to be consumed in production by using continuously cast materials or capped steel materials and specifying the temp. of hot finish rolling in production stages and the thickness of hot rolled blank materials. CONSTITUTION:The continuously cast slab of the steel contg., by %, <=0.08C, <=0.03 Si, 0.12-0.30 Mn, <=0.030 P, <=0.030 S, <=0.06 Al, and the balance iron and unavoidable impurities and >=10 Mn/s is hot rolled. In this time, the finish rolling is completed at the Ar3 point -700 deg.C, then the steel plate is coiled at 600-450 deg.C to provide a hot rolled steel strip of 1.6-2.3mm. thickness. In succession, the steel strip is cold rolled after descaling by pickling or the like. Here, the limitation of C results in decreased yield strength of the hot rolled plate and improved cold rolling performance. Since this effect is observed in hot rolling below the Ar3 point, the upper limit of the hot rolling is set at the Ar3 point. The temp. for heating slabs is made lower than in the prior art and the thickness of the hot rolled strip is decreased. Thus the original unit of quantity of heating is reduced, and the cold rolling is accomplished in the good finish state advantageously in terms of energy and working efficiency. |
