PRODUCTION OF CAST PRODUCT INSERTING SILICON NITRIDE AS CAST-IN

PURPOSE:To prevent the development of blow defect in a steel cast body contacting with a formed material by coating slurry dispersing refractory powder into inorganic binder liquid on the surface of the formed material of silicon nitride preceding to inserting as cast-in. CONSTITUTION:The formed material 1 of silicon nitride is dipped into the slurry composed of the inorganic binder of colloidal silica, etc., and the refractory powder of silica flour, zircon flour, etc., and drawn up nd dried. This formed material 1 is laid into a wax injection metallic mold and a wax pattern inserting the formed material 1 is manufactured by the injection formation of the molten wax. Plural pieces of these wax patterns are fitted to the periphery of a wax column to form a tree, and a mold is manufactured by a method alternately applying the coatings of refractory slurry and stucco on the surface at plural times. Then, heating and dewaxing are executed and the remained mold is burnt. Molten metal is poured in this mold to obtain the steel cast body 1 inserting the formed material 1 as cast-in.