| 摘要 |
PURPOSE:To introduce a mold without any vent hole and to improve the material yield by laying the mold in a vessel, reducing pressure in the vessel at the specific vacuum degree and melting and pouring titanium under atmosphere enclosing argon gas at the specific pressure. CONSTITUTION:A cover 2 is closed on a tank 1 and the pressure in the tank 1 is come to reach to 1X10<-1>Torr by a vacuum pump 11. After that, argon gas is blown in the tank 1 from a gas cylinder 12 at 200-300Torr to keep negative pressure argon atmosphere. Then, a rotating table 8 fitted to a driving shaft 9 is rotated at the prescribed number of revolution by a driving motor 10 through a pulley. Next AC voltage is applied on between an electrode (-) 4 fitted to an electrode holder 5 and a titanium or its alloy material (+) 13 set on the upper part of a crucible 6, to melt the material 13 by electric arc discharge. The molten material dropped naturally is flowed into the mold 7 through a runner 7' to obtain the product.
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