GB661932A - Improvements in means for joining metals by soldering or brazing - Google Patents

Abstract

661,932. Soldering and brazing. GENERAL ELECTRIC CO., Ltd., WILLSON, C. R., and TOLCHARD, E. Feb. 13, 1950 [April 20, 1949], No. 10412/49. Class 83 (iv). Joints.-In producing a soldered or brazed angular joint, the two cleaned metal surfaces to be joined are overlapped by bending the edge of one or both surfaces so that they are in close approximation, a soldering &c. metal is applied to the inside of the joint and is held by a jig after which the joint is heated from the outside until the solder &c. flows throughout the length of the joint, the joint being finally cooled below the melting point of the solder &c. before removal of the assembly from the jig. In the production of a metal can, four pieces of solder, with or without flux cores, are placed in slots 1 in a jig centre portion 5 made of aluninium, nickel-chrome steel, ceramic or other material not wetted by solder, top and bottom plates are placed in position on the drilled or channelled jig portion 5 and butted against stop plates 2, and the side members are placed with their edges on the outside of the top and bottom plates. The assembly may be held by a clip. The joint is coated from the outside with a flux, e.g. to 50 per cent phosphoric acid, 50 per cent water, plus a few drops of surface tension reducing agent, e.g. a sulphonated oil. The assembly is inserted between a fixed jaw 3 and an air pressure operated movable jaw 4 of the soldering jig and a high-frequency current is passed through an induction coil 7 surrounding the assembly. A compressed air blast means 10 in the jaws of the jig may be employed to cool the assembly and when the solder has set the assembly may be immersed in water &c. The jaws 3, 4 of the soldering jig which are electrically non-conductive may be of ceramic, asbestos, fireclay, etc.; the current employed may be 10-30 mc/s. Flame or radiant heating may replace the induction heating.