| 摘要 |
PURPOSE:To vent gas in the stage of injecting molten metal and to prevent the intrusion of the gas into molding and the deterioration in shape accuracy by providing vent holes formed of porous ceramics to an injection nozzle body for die casting made of ceramics or heat resistant metal. CONSTITUTION:The injection nozzle body 1 for die casting made of the ceramics or heat resistant metal having heat resistance and wettability is fitted to the goosenecked 4 top end of a molten metal melting pot 3 and the top end thereof is press-contacted with an inflow port (n) of a molding tool (m). A suitable number of the vent holes 2 contg. the porous ceramics communicating with a pouring passage 1a are provided. The air and gas in the passage 1a are vented by the porous ceramics (a) in the stage of injecting the molten metal by a plunger rod 5 to prevent the intrusion of the gas into the molding and to prevent the reduction of pressurizing force by which the shape accuracy of the molding is improved. The air enters the molten metal when the unpacked metal return but the venting of the gas is made in the stage of reinjection. The subsequent moldings are thus made non-defective. |
