| 摘要 |
PURPOSE:To obtain a casting having good quality by improving a running ability of molten metal while restraining the development of blow hole in the casting in a low pressure casting. CONSTITUTION:By pressurizing a furnace space 20 while reducing the pressure in a cavity 12, the molten metal 16 in a melting furnace 18 is filled up into the cavity 12. By this method, it is prevented that back pressure 12 is developed in the cavity at the time of filling up the molten metal 16, and the running ability of the molten metal is improved. Further, after filling up the molten metal, the pressure reducing is stopped and also the pressurizing condition is kept to a prescribed time. By this method, the pressurization to the molten metal 16 filled up into the cavity 12 can sufficiently be executed and by this feeder head action, it is restrained to the min. limit that the blow hole in the inner part of the casting is developed, and the structure in the casting is made to be compact. |
