APPARATUS FOR PRODUCING SLAB AND INGOT HAVING FINE CRYSTAL STRUCTURE

摘要

PURPOSE:To obtain a slab and ingot having fine crystal structure by detecting the molten metal surface temp. in a casting mold and controlling said temp. so as to be kept within the range between the liquidus line temp. and solidus line temp. of a material to be cast. CONSTITUTION:The opposed parts of electrodes 11 are melted by the heat of an arc 13 and drop in the form of liquid drops 14 when electric current is supplied to the electrodes 11. A sensor 15 detects the molten metal surface temp. in the casting mold 12 and after the detection signal thereof is calibrated by a signal processor 16, the output signal thereof is fed to a temp. control device 17. The temp. control device 17 increases the current to be supplied from a current supply device 18 to the electrodes 11 to increase the arc temp. between the electrodes 11 when the molten metal surface temp. in the casting mold 12 is lower than the solidus line. The melting speed of the liquid drops 14 is thereby increased and the molten metal surface temp. is increased. On the other hand, said device decreases the current value between the electrodes 11 when the molten metal surface temp. rises higher then the liquidus line. The melting speed of the liquid drops 14 is thereby decreased and the molten metal surface temp. is decreased. The molten metal surface temp. in the casting mold 12 is thereby maintained within the range between the solidus line temp. and liquidus line temp. of the material. The slab having the fine crystal grains is thus stably obtd.