METHOD FOR CONTINUOUSLY CASTING SQUARE BILLET AND MOLD FOR CONTINUOUS CASTING

摘要

PROBLEM TO BE SOLVED: To prevent the development of deformation, crack, etc., of solidified shell and to improve the billet quality by setting the ratio of take-out heat flow speed of corner parts and side surface parts of a mold at a specific range and changing drawing-out speed and/or electromagnetic stirring flow speed according to the heat conductive ratio. ;SOLUTION: Electromotive forces generated in thermocouples 2 embedded at the side surface parts and the corner parts of the mold 1 existing in the same distance from the solidified starting point 5 of poured molten steel, are converted into mold temp. data with a converter and through an arithmetic device, the heat flow speed q_f at the side surface part and the heat flow speed q_c at the corner part are obtd. with q_f=K_f×(T_f-T_w) and q_c×(T_c-T_w), respectively. Wherein, K_f, K_c and T_f, T_c are overall coefficient of heat transfers and temps. of thermocouples at the side surface part and the corner parts, respectively. This permissible range of the take-out heat flow speed ratio is made 30-70% and when the ratio exceeds the range, the drawing-out speed is lowered and the flowing-in of powder is promoted or the electromagnetic stirring flow speed is reduced and the molten metal surface is raised, and thereby the uniformity of the solidification is recovered.;COPYRIGHT: (C)1998,JPO