PURPOSE: To obtain a high quality casting by making rising velocity of the differential pressure comparatively slow at the time of starting filling-up of molten metal into a cavity in a mold and successively, adding the differential pressure to a feeder head after the completion of the filling-up confirms with a detecting means arranged at the last filling part in the cavity.
CONSTITUTION: The atmospheric pressures in a holding furnace 1 in a pressure vessel 2 and in the mold 5 are independently controlled and the molten metal in the holding furnace 1 is filled up into the cavity in the mold 3 through a stoke 5 with the differential pressure. At the time of starting the filling-up of the molten metal into the cavity, the rising velocity of the differential pressure is made to comparatively slow, and after the completion of the filling-up confirms with the detecting means S for the filling-up of the molten metal arranged at the last filling part in the cavity, successively the differential pressure for feeder head is added. By this method, the change-over timing from the pressurization for filling up to the pressurization for feeder head is made to suitable, and as the molten metal is filled up in so comparatively slow velocity as not to develop the disturbance of the molten metal and entrapping of gas in the cavity, the high quality casting can be obtd.
HAMA YASUO
WATANABE HIROSHI
