| 摘要 |
PURPOSE:To obtain a billt or ingot which has fine crystal structure and has no surface defects by providing a casting mold, liquid drop casting means which drops the liquid drops of a molten metal into the mold, a coil for high-frequency induction heating of the surface of the molten metal in the casting mold and high-frequency power source. CONSTITUTION:The opposed ends of electrodes 11 melt and the liquid drops 14 of the molten metal drop when an arc 12 is formed by the conduction of electricity between the electrodes 11. The liquid drops 14 are cooled during the time when the drops fall from the electrodes 11 into the casting mold 13, thus the liquid drops are cast in a half-molten state into the mold 13. The half-molten metal 16 is cooled and solidified by the mold 13 in the state in which the solid-liquid co-existence phase exists uniformly therein. The crystal grain size of the solidified structure of the resultant billet 15 is therefore fine. The billet 15 is continuously pulled downward. High-frequency current is supplied from a high-frequency power source to the coil 20 embedded in the mold 13 in this case, by which the half-molten metal 16 near the meniscus is subjected to the high-frequency induction heating.
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