| 摘要 |
PURPOSE:To produce a thin-walled and defect-free Mg alloy product having an intricate shape by vacuum casting by introducing nonoxidative gas into a holding furnace for a molten Mg alloy, closing hermetically the furnace, evacuating the cavity of a casting mold and filling the molten alloy therein. CONSTITUTION:A mold holding means 17 which holds a sand mold 11 is lowered to immerse the mold aperture 15 into the molten Mg alloy in the furnace 1. When the inside of a product cavity 14 is evacuated by sucking the air in the mains 17 through an evacuating port 18, the molten alloy 2 is filled through the sprue 15 into the cavity 14. The means 17 is moved upward upon ending of solidification to close hermetically the aperture 4 of a furnace cover 3. When the molten Mg alloy 2 in the furnace 1 decreases on repetition of the casting, nonoxidative gas is introduced therein through an introducing port 10 to exert an adequate pressure on the metal 2 thereby rising the surface thereof and maintaining the specified bath surface. The product of the Mg alloy having no deterioration in corrosion and gaseous defects tis thus produced by vacuum casting. |
