| 摘要 |
PURPOSE:To prevent the penetration of molten aluminum and to obtain a casting having excellent surface by forming two layers of coating layer on surface shell core formed by resin coated sand. CONSTITUTION:The shell core 1a is formed into the prescribed shape by using organic binder, and on the surface, slurry composing of acid acqueous solution of powdery refractory and thermosetting resin are coated to form a first coating layer 2 after drying this. Next, under no cooling said body the thermosetting resin is coated on the surface as high temp. and after leaving at room temp. and drying, the core 1 is produced by forming a second coating layer 3. During drying the first coating layer 2, the acqueous solution penetrated in shell core 1a is shifted to the surface together with vaporizing, and then water soluble thermosetting resin is shifted to the surface, too, and is gradually concentrated. Therefore, by coating the thermosetting resin as high temp., curing agent and the resin react and harden and as film is formed, the penetration of molten aluminum, etc., is prevented.
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