GB390141A - Improvements relating to coating metallic bodies with an alloying metal - Google Patents

Abstract

390,141. Electroplating. ELECTRIC FURNACE CO., Ltd., 17, Victoria Street, London.-(Assignees of Northrup, E. F. ; Ajax Park, Trenton, New Jersey, U.S.A.) June 25, 1931, No. 18420. Convention date, June 27, 1930. Void [Published under Sect. 91 of the Acts]. [Class 41.] A metal, such as iron or steel, is provided with a hard surface layer by coating it electrolytically with another metal or metals, e.g. chromium, and fusing the coating to the foundation metal by the inductive action of highfrequency currents traversing an induction coil in proximity to the metal. The method is particularly applicable to the formation of hard layers on the interior surfaces of cylinders of automobile engines or on the exterior surfaces of rolls. In treating the interior of a cylinder 10, Fig. 1, which is coated with a layer of chromium or of chromium and nickel, an induction coil 11 is arranged coaxially inside the cylinder and spaced therefrom by an insulating layer 12. In treating a roll 23, Fig. 5, a coil 11<1> is arranged coaxially around the roll and spaced therefrom by an insulating layer 12<1>. The cylinder or roll is preferably heat treated before coating at a temperature higher than that to which it will be subjected in working and is then ground to the exact dimensions. Electrical circuits for obtaining the necessary rate of heat input are described and illustrated in Figs. 4, 6 and 7 in which 14, 15 represent the leads from the electric supply, 11, 11<1>, 11<2>, the induction coils, 16, 16<1>, 162 additional resistances, and 17, 17<1>, 172 capacities.