PURPOSE: To perfectly prevent oxidation of molten metal and to provide a stoke as suitable to this casting method by covering the molten metal surface with inert gas.
CONSTITUTION: By supplying the inert gas 22 into a stoke, a product 9 and the molten metal 7 are separated. Further, in the stroke for differential pressure casting, having an inner cylinder 11 connecting the upper end with a sprue in a metallic mold and holding the lower end higher than the surface 8 of molten metal 7 in a holding furnace and outer cylinder 12 closing the upper end at between this cylinder and outer face of the inner cylinder 11 and submerging the lower end into the molten metal 8 and arranging a hole for communicating annular range 13 formed at between the inner and outer cylinders 11, 12 with the outer part, one or plural notching parts 15 are arranged upward in peripheral direction of the lower end of inner cylinder 11.
ONISHI SANETSUGU
IIZUKA YASUO
OKADA CHISATO
YASHIRO TOSHINORI
