| 摘要 |
<p>PURPOSE:To enable the removal of residues from a crucible for melting and the recovery of only the lower electrode by constituting the lower electrode mounted to the crucible in such a manner that said electrode can be freely inserted to and detached from the crucible. CONSTITUTION:The lower electrode 2 is freely removably inserted into a through-hole 8 provided through a melting chamber 6 into the base of the crucible 1. A pure Ti or Ti alloy ingot is put into the crucible 1 and the top end of the electrode 2 is exposed into a chamber 6 in an Ar atmosphere and an arc discharge is generated between said electrode and an upper electrode 7 to melt and cast the Ti material. The melt of the Ti material remains on the inside surface of the chamber 6 at this time and these residues 4 harden and stick to the part of the electrode 2 exposed from the base of the chamber 6. These residues oxidize and the oxides intrude into the next melt, thereby giving the cause for the generation of a defective product and the hindrance of the arc generation. The electrode 2 is, therefore, moved upward. The residues 4 can be thereby removed together with the electrode 2 from the inside of the chamber 6. The residues 4 sticking to the top end of the electrode 2 removed from the crucible 1 are easily separated by hammering, etc.</p> |
