GB1155608A - Inlaid Material - Google Patents

Abstract

1,155,608. Making composite metal strip; soldering; welding by pressure; jointing by rolling. JOHNSON, MATTHEY & CO. Ltd. 23 Aug., 1967 [23 Aug., 1966], No. 37711/66. Headings B3A, B3M and B3R. A method of making an elongated body or strip inlaid with one or more strips of another material comprises providing the first strip with one or more grooves having a narrower mouth than base when the strip is transversely flat, deforming this strip into transversely arcuate form, inserting the inlay in the groove while the strip is deformed, and flattening the deformed strip or the deformed part thereof in a transverse direction so that the walls of the groove close on the strip to lock it in position. As shown, inlayed material for contact arms is made from backing strips of copper or copper alloy inlayed with strips of silver or silver alloy in a continuous process. The backing strip 1 is curved laterally between rolls 2, 4, Fig. 4, or (2, 3), Fig. 1 (not shown), and grooves 9, 9<SP>1</SP>, 9<SP>11</SP>, Fig. 2, of rectangular cross-section are milled on the convex surface of the deformed strip or formed between the rolls. The strip is then fed over a further barrel-roller 6 of the same or smaller radius B than roller 2 to facilitate introduction of the inlays into the grooves. A further operation, between rollers 10, 11, flattens the strip, preferably reducing its thickness, and contracts the grooves. A metallurgical bond may be produced if the opposing surfaces are cleaned, as with a scratch brush, and the strip passes from rollers 10, 11 through a furnace with an atmosphere of cracked ammonia and then between a further set of rollers. The groovewalls may be pre-tinned, and furnace-heating may be effected in two stages, firstly to solder the components and then to diffuse the tin away from the interfaces; a rolling operation may be interposed between the two stages. Alternatively, the strip may be substantially reduced by cold-rolling at high-speed to effect bonding. The inlays need not be flush with the surface of the base strip, Fig. 7 (not shown).