GB568303A - Improvements in or relating to the casting of metals - Google Patents

Abstract

568,303. Casting. PROCTOR, W. F., and WEBB, G. W. July 22, 1943, Nos. 11919 and 19741. [Class 83 (i)] Casting-machines ; moulds; castings extracting.-Slabs, parts of aeroplanes, boats, wheels, or other castings of aluminium or magnesium alloys, &c., having a surface area of over 12 square inches, are cast by forcing molten metal through a conduit system 3 ... 7 to exits 8a ... 8e and through them and a fixed die member 1 which has a uniform thickness where it defines the casting C. The molten metal is delivered by a piston to the conduit system at 3 and 4 while 5 is connected to a supply of nitrogen, chlorine, &c. by a pipe 5a so that, when the casting has solidified and the piston is returned, the metal in the system 3 ... 7 is returned to the forcing cylinder followed by nitrogen &c. which fills the conduits ready for the next operation. The die 1 conforms to or, as shown,' forms the wall of a chamber 2 in which a conduit system, which may be similar to that described in Specification 549,238, is arranged and which contains molten salt, fusible metal or other liquid heated to the best temperature for casting the particular metal being used, e.g. 640‹ C. for " Y " aluminium base alloy. The casting will, therefore, freeze first at, and adhere to, the movable die 13, this being ensured by arranging hollow inserts 14, Fig. 2, supported by hydraulic rams 14a, in said die 13. Casting composite articles.-The gates 10 are formed in inserts 9 arranged in the exits 8a &c. of the die 1, all the inserts 9, 14 being shaped to adhere to the casting when the die is opened and the casting ejected by hydraulic rams 14b engaging the inserts 14. The inserts are made of a metal having a higher melting point than that of the metal cast. The outside form of the inserts 14 allows them to be inserted in the part 13 by rams 14a after closing the die and, after casting, they are at such a high temperature that they are readily deformable and can be pushed up by the rams 14b out of their housings. In a modification, each gate insert 17, Fig. 3, is connected to an ejector insert 19 either integrally or by a screwed rod 24 of the same metal as that cast. If the metal is cast at under 650‹ C., aluminium inserts 9, 14, 17, 19 may be used. If the inserts are of heatresisting iron they may be re-used. In any case, they are severed from the casing when cold.