| 摘要 |
PURPOSE:To suppress the cooling of molten metal in the initial period of charging and to prevent the generation of a misrun by coating a mold coating material contg. mica on the surface of a chiller body in contact with the molten metal. CONSTITUTION:A sprue 2 and a product cavity 3 having a vane part 3a and a hub part 3b are provided to a gypsum casting mold 1 for a compressor wheel. A chiller body 4 is assembled on the bottom surface in the part 3b of the cavity 3, and a coating film 5 is formed beforehand on the surface where the body 4 contacts with molten metal by a mold coating material contg. mica 5a. The film 5, which has gaps 5b among the particles of the mica 5a and is highly gappy, suppresses the transmission of heat to the body 4 by the heat insulation effect of the gaps 5b in the initial period of charging, thereby preventing the deterioration in the fluidity of molten metal owing to the cooling of the molten metal and improving the run to the part 3a. When the molten metal is filled in the cavity, the gaps 5b are eliminated by the pressure of the molten metal, and the cooling effect by the body 4 is provided. |
