| 摘要 |
PURPOSE:To perform direct rolling which suppresses the generation of hot cracking by controlling adequately the cooling speed of an ingot in the stage of continuous casting as well as the temp. for starting rolling in the stage of direct rolling and the time when said temp. is attained. CONSTITUTION:An ingot for a thick plate or the like produced by continuous casting is subjected, after the casting, to cooling at the average cooling rate Vc ( deg.C/min) from 1,500 deg.C near the surface of the ingot up to 1,300 deg.C satisfying the conditions expressed by a functional equation I with a constant K (where, x: content of C, y: content of O). The ingot is further subjected to hot rolling for the lapse of time tmin since solidification until the rolling is started and at the surface temp. of the ingot in the stage of starting rolling satisfying the conditions of the relation II. Since the rolling free from hot cracking is accomplished with the effective utilization of the heat after the casting by the above-mentioned control for temp. conditions, the cost of energy is reduced. |
