| 摘要 |
PURPOSE:To obtain a hot-rolled steel plate for general processing use which is capable of being formed without performing surface treatment and can be covered on the surface by hot-rolling after reheating a continuously casted billit having a specified compsn. at a specified temp. and winding at a specified temp. and then cooling in a nonoxidizing atmosphere to a specified temp. CONSTITUTION:A hot billet is obtd. by continuous casting after melting a steel consisting of 0.03-0.25wt% C, <=0.02wt% Si, 0.20-1.00wt% Mn, <=0.020wt% P, <=0.010wt% S, <=0.02wt% Cu, <=0.02wt% Cr, <=0.05wt% Al, and residual wt% Fe. The product is fed to a heating furnace as it is, or reheated at 1,230-1,300 deg.C after cooling once, and rolled roughly at hot and finish-rolled to a desired plate thickness, and wound at 550-700 deg.C. The wound coil 1 is conveyed to a working bed 3, covered with a close cover 4, sealed with water 2. Thereafter, either one of gaseous N2 or Ar or both are blown through nozzles 7a and 7b, and 7c and 7d to cool the coil 1 to 350 deg.C. |
