| 摘要 |
PURPOSE:To decrease the casting defects of a casting and to improve the quality thereof in casting using a sand mold by keeping feeding a cooling gas to the inside of the sand mold until a molten metal solidifies before and after a pouring operation into the product cavity of a casting mold. CONSTITUTION:A molten alloy is poured into the product cavity 3 formed of a metallic mold and sand core 2 (sand mold). A vacuum pump 7 is operated by using a valve 6 to evacuated and suck the inside of the sand core 2 at the point of the time when the molten metal is nearly filled into the product cavity 3. The air in the atm. is therefore sucked through the inside of the sand core 2 and a conduit 5 to the vacuum pump 7 side. Since the sand core 2 is mainly constituted of sand particles 8, there are gaps among the sand particles 8 and the air flows by passing through the gaps to cool the sand core 2. The vacuum pump 7 is stopped and the casting 9 is taken out of the mold 1 when the molten metal solidifes. The generation of the casting defects such as shrinkage cavities and pinholes to the casting 9 is thereby suppressed.
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