| 摘要 |
PURPOSE:To obtain sufficient compression strength and to improve the decaying of a sand after molten metal pouring as well by forming the surface layer of a core for casting in solid shape and forming the casting sand inside the surface layer in non-caking. CONSTITUTION:The core for casting taking out of a die is taken out after holding it by dipping for 10-20 min in the 10-50% sodium silicate water soln. heated at 80 deg.C and calcined for two hours at 800-1000 deg.C. As a result, the core 4 for casting on which a casting sand 3 is formed in granular shape is formed on the surface layer 1 formed in solid shape and the inside 2 of the surface layer 1. The core 4 has enough compression strength and the decaying of the sand after pouring a molten metal is good.
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