| 摘要 |
PURPOSE:To prevent development of cold shut and surface fold at the time of filling up molten metal by arranging coating layer for preventing the molten metal penetration except die surface part corresponding to the specific part, in which gas is easily stayed, at the time of filling up the molten metal into a cavity in the die. CONSTITUTION:It the case of producing a cylinder head for engine, etc., a collapsible mold 7 and a collapsible core 8 are set in one set of the dies 1-6. At the time of filling up the molten metal into the cavity 9 in a pressure casting, the collapsible mold 7 and core 8 are tolerated to the molten metal pressure but easily collapsed after casting. Except the specific part 7a...7a, 8a...8a, in where the gas easily stays at the time of filling up the molten metal in the cavity 9, the coating layers 10, 10 are arranged on the surface of the expendable mold 7 and core 8. The coating layers 10, 10 are used for preventing the molten metal penetration and formed by applying liquid slurry of metallic oxide, etc. By this method, the cold shut and the surface fold generating in the gas easily staying part in the shape are prevented and the development of crack in the product can be prevented.
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