| 摘要 |
<p>PURPOSE: To enable a more high degree vacuum state to be realized by a method wherein an induction heating coil of a cold-wall vacuum induction melting furnace and an inter-furnace wiring are formed of a water-cooled copper pipe not covered with an insulation cover and further a composing element such as a vacuum tank is processed to have a smooth surface by an electrolytic grinding and a chemical grinding or the like. CONSTITUTION: An induction heating coil 8 of vacuum pipe arranged at an outer circumference of a main body 1 of a cold-wall vacuum melting crucible stored in a vacuum tank and a vacuum conduit 4 for electrically connecting between the induction heating coil 8 and a power supply and performing a cooling of the induction heating coil 8 ar formed of a bare copper pipe having no insulating coverage so as to eliminate a gas discharged out of an insulation covering layer. An inner surface of the vacuum tank and/or an entire surface of the main body 1 of the cold-wall vacuum melting crucible is smoothed through an electrolytic grinding plus complex grinding, and a glass-bead blast processing. With such an arrangement as above, gas discharged out of the surface of the main body 1 is reduced and a vacuum-reaching pressure is further reduced.</p> |
