GB1337731A - Casting method and apparatus - Google Patents

Abstract

1337731 Casting machines ASSOCIATED ENG Ltd 19 April 1971 [21 Jan 1970] 3051/70 Heading B3F Casting apparatus comprises a mould 21, conduits 34 for introducing molten metal into the mould, and means 41 for cooling the exterior of the mould, the mould being movable relative to the conduits and cooling means so that the length of that portion of the mould which is subject to the action of a coolant increases as the level of molten metal in the mould rises. The rate of introduction of the metal and the rate of lowering of the mould are preferably such that the outlets of the conduits 34 are maintained at a predetermined distance above or below the level of the molten metal in the mould. In the embodiment shown, the mould consists of two tubular parts 21 and 22 and may be used to cast a piston having an insert 27. The part 22 may be provided with cooling fins on its underside. The two parts 21 and 22 are initially separated and the lower part 22 positioned so that it is heated by burners 40. After preheating the cast iron insert 27 in a bath of molten aluminium, it is placed in the lower part 22 of the mould which is then filled with metal until the insert is just covered. The parts 21 and 22 are then clamped together, metal introduced into the mould through the conduits 34 and the mould gradually lowered together with a spray head 37. The cooling spray ring 41 and the burner ring remain stationary. In another embodiment the mould is provided with a sand core (10) supported by lugs (11) and is cooled by lowering it into a tank of water. Directionally solidified pistons made of an aluminium or magnesium base alloy may be produced.