| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress the secondary contamination of melt by melting a metal in clean environment and to allow impurities easily removed without depending on a gas bubbling or filtering. <P>SOLUTION: As a melting furnace in this invention 11, a melting furnace which is constructed to give high frequency induction heat to a graphite cylinder 19 with an induction coil 20 for melting a raw material 26 to be melted with the heat of the graphite cylinder 19 is used. The melt 27 staying at the bottom of the melting furnace 11 is introduced in a fixed amount through a melt supply passage 14 to be opened/closed by a stopper 16 to a vacuum treatment tank 12. The vacuum treatment tank 12 is depressurized to a 133 Pa or less by a vacuum pump 24 for batch degassing and oxide removing operation. The melt 27 purified by the vacuum treatment is carried from the bottom of the vacuum treatment tank 12 through a melt discharge passage 15 to be opened/closed by a stopper 17 to a draw-out tank 13, in which it is held at a fixed temperature by a graphite heater 24. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
