Importance

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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. On the other hand, while the reaction force is low so that there is a delay in the solidification of molten metal, the speed of advancement is reduced so that no pressurizing force is applied until completion of solidification of molten metal. The pressurizing pin is advanced while its advancement speed is controlled in the above way, and pressurizing over the entire stroke is completed.

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First Claim