| 摘要 |
PURPOSE:To maintain high surface stability even if a green sand mold is dried and the compactability thereof decreases by using grape sugar, fruit sugar, etc. as an additive to molding sand for green sand mold consisting essentially of silica sand-bentonite-water. CONSTITUTION:7.5 parts bentonite, 0.5 part fruit sugar (isomerized sugar) and 1.8-2 parts water are compounded with, for example, 100 parts silica sand (fluttery sand) and the mixture is kneaded to manufacture the green sand. The amt. of the water to be added is so adjusted in this stage that the compactability after the kneading attains 35% and 45%. The green sand has a low moisture content and high surface stability and even if the compactability thereof decreases as a result of drying, the sand maintains the high surface stability. The production of a casting having high quality is thus made possible. |
