| 摘要 |
PURPOSE:To obtain a casting product free from oxygen without coming into reaction with a crucible by forming thin oxide layer on outer surface except upper face of material for casting having high activity at high temp. CONSTITUTION:At the time of manufacturing an ingot 9, high frequency induction heating coil is set facing to the whole outer surface except the upper face 23a of titanium material 23 and the outer surface is rapidly heated at the prescribed temp. in a short time under oxygen atmosphere. In this case, as the oxide layer 24 is allowed to remain as solid-state without melting, the molten titanium material 23 is not brought into contact with surface of recessed part 10 in the crucible 8 and the titanium material 23 is not oxidized by the reaction with the crucible 8. |
