Improvements relating to the manufacture of centrifugally cast plural-metal articles

摘要

617,128. Casting composite articles. SHEEPBRIDGE STOKES CENTRIFUGAL CASTINGS CO., Ltd., and STOKES, J. E. Sept. 2, 1946, No. 26397. [Class 83 (i)] Centrifugal casting- machines.-In a method of making composite metal articles, particularly brake drums, wherein a layer of metal is centrifugally cast onto a foundation 3 of another metal, the foundation is preheated in situ on the casting machine by a high frequency induction coil 2, the heating current is switched off and the lining is cast. The foundation 3 is clamped by a nut 15 to a connector 6 in the form of a tubular boss screwed into the end of a rotatable shaft 1 coaxial with the coil 2, which overhangs the foundation 3 at each end to ensure that the full induced current flows through the whole length of the foundation. The considerable clearance between the coil 2 and the foundation 3 provides a loose electromagnetic linkage which is necessary to prevent the induced currents concentrating on the outer surface only of the foundation 3, which may also be rotated during preheating, the time of which is prolonged, to ensure even heating. Suitable fluxes may be used to ensure satisfactory welding of the two metals.