GB520598A - Improvements relating to the production of metal castings - Google Patents

Abstract

520,598. Casting processes. BAILEY, R. W., METROPOLITAN-VICKERS ELECTRICAL CO., Ltd., and ENGLISH STEEL CORPORATION, Ltd. Oct. 26, 1938, No. 31004. [Class 83 (i)] Cores ; moulds ; casting composite articles.-In the casting of hollow articles, e.g., hollow steel ingots, segregation is reduced by cooling the core 3 internally by a removable solid body 8 arranged therein, and this body when hot is replaced by a cool body of the same or a different shape. Cooling may be assisted by the passage of air or other fluid through the core and this may be assisted by a jet of air, steam, &c. at 6. The core may include a shell 21, Fig. 2, arranged about the hollow core 3 to which its lower edge may be welded. The shell 21 may be longitudinally corrugated and is thin enough to soften, after solidifying a layer of the cast metal, or otherwise yield easily as the ingot shrinks. The shell may become bonded to the casting or this may be prevented by a suitable coating. The space 29, between the shell 21 and core 3, or 59, between the core and body 8, may be filled, progressively or otherwise, with lead or other metal, alloy, or salt having a low melting-point, e.g., by means of an electrically heated pipe 32, a melting pot 30, and compressed gas in a container 35. Whether the space 59 is filled with lead &c. or not its radial dimension may vary at different points along the length of the core to vary the rate of cooling. An insulating sleeve 28, Fig. 2, may be arranged in a recess in the core to reduce the rate of cooling in the head 4 and an insert sleeve 27, to be cast into the head of the ingot, may be placed on the upper end of the core. The shell 21 may comprise a thin sheet wrapped so that its sides overlap and tacked or joined, e.g., by welding. Specification 360,980, is referred to.