| 摘要 |
PURPOSE:To improve the cooling capacity for a casting mold and to make the shake-out in the stage of casting easy by disposing mixed sand which is mixed with iron grains at a specific volume ratio as facing sand. CONSTITUTION:A film 4 is sucked and adhered tightly on the surface of a wooden pattern 3, whereafter the mixed sand mixed with a granular refractory material such as silica sand and iron grains is disposed as facing sand 11 thereon at a prescribed thickness. The compounding ratio of the granular refractory material and the iron grains is determined so as to contain the iron grains within a 20-100vol% range. Backing sand 12 consisting of molding sand for vacuum casting such as silica sand is charged on the sand 11 up to around the upper part of a metallic flask 6 after the facing sand 11 is disposed, and in this state, the sand is oscillated so to be packed. The top surface in the opening of the flask 6 is sealed tightly with a film 7, and the sand 11 and sand 12 in the flask 6 are solidified with a vacuum pump 8 and suction pipes 9, 10; thereafter, the pattern 3 is parted and the casting mold for vacuum casting is obtained. |
