| 摘要 |
PURPOSE:To prevent the generation of the surface defects of castings occuring in the temp. drop of cast molten metal by coating two layers of mold coating materials consisting of specific materials on the inside surfaces of dies for casting. CONSTITUTION:A slurry of water consisting essentially of diatomaceous earth and mixed with a small amt. of bentonite is coated by a wet spray method on the inside surface of a die 1 for casting, whereby a heat insulation layer 2 is formed. Next, mixed slurries of SiO2, etc., contg. >=40% Al2O3 are coated thereon by a wet spray method, whereby a refractory heat insulation layer 3 is formed. If molten metal is cast into the die having two layers of such mold coating materials, the temp. drop of the molten metal in the die is reduced considerably, and the generation of the outside surface defects such as pinholes, blows or the like in a casting 4 is reduced. |
