| 摘要 |
PROBLEM TO BE SOLVED: To surely obtain the separation between an as-cast product and a green sand mold and the collapse of the green sand mold. SOLUTION: The flaskless green sand mold already poured with molten metal is air-tightly surrounded, and the inner part of a structural body air-tightly surrounded, is quickly sucked and the pressure therein is reduced to make a negative pressure state therein. This negative pressure state is kept for a fixed time and the b.p. of the moisture is lowered in the whole green sand mold containing the water in the moisture condensated layer formed in the surroundings of the as-cast product in the green sand mold to boil this moisture. In this way, the green sand mold is collapsed and separated from the as-cast product. Thereafter, the air-tightly surrounding state is released to take out the as-cast product.
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