Abstract: In a method of integrally attaching a hollow member to a cast product by casting so that the hollow member communicates with a hollow interior of the cast product, a closure member is fitted into an open end of the hollow member so that the open end of the hollow member is closed by the closure member. The closure member projects from a core for forming the hollow interior of the cast product in a direction different from a direction in which the core is drawn out of the cast product. A molten metal is poured into a casting mold after the casting mold has been clamped. The closure member is moved inside the core after solidification of the molten metal so that the closure member is released from the fitting in the hollow member. The core is drawn out of the solidified metal subsequently to the moving step of the closure member.

Abstract: A pressure casting method is disclosed, which permits sufficient pressurizing effect to be obtained for the entire molten metal by varying the speed of advancement of a pressurizing pin according to the state of solidification of the molten metal during pressurizing. In pressure casting using a pressure casting apparatus, while charged molten metal is solidified, it is pressurized by causing advancement of the pressurizing pin into a cavity of the die. During this time, the reaction force received by the pressurizing pin from the molten metal is measured by a pressure sensor, and the speed of advancement of the pressurizing pin is varied through control of the opening degree of a flow control valve according to the measured reaction force. While the reaction force during the progress of solidification of molten metal is high, the flow control valve is controlled to a high opening degree to provide for a high speed of advancement of the pressurizing pin so as to apply a high pressurizing force.

Abstract: The disclosed method of controlling a pressurizing pin, which serves to replenish for the necessary locality with molten metal during solidification of molten metal charged in the cavity, features that the operation of the molten metal replenishment by the pressurizing pin is caused when it is detected that the volume of non-solidified metal has become less than the volume effective for obtaining a molten metal replenishment effect. It is thus possible to obtain efficient replenishment for the necessary locality with molten metal by using a pressurizing pin which is limited in size and stroke.