GB846808A - Improvements in or relating to brazing processes - Google Patents

Abstract

846,808. Coating with metals; alloys. WESTINGHOUSE ELECTRIC CORPORATION. July 11, 1958, No. 22298/58. Classes 82(1) and 82(2) [Also in Groups XXII and XXXVII] A refractory metal member is brazed to a member of aluminium, magnesium or their alloys by heating the members and applying an aluminium brazing alloy to the surfaces to be joined to melt the alloy, vibrating the molten alloy at least to 9,600 cycles per second, to form coatings on the members, and bringing the members together while the alloy is molten. The refractory metal may be tungsten, nickel, molybdenum, tantalum, platinum group metals, their base alloys or carbides, or as alloys or sintered and pressed mixtures with silver, copper, gold, tin or cadmium. A cup-shaped contact tip 10, Fig. 1, in the form of a pressed and sintered mixture of a refractory metal and a conductive metal is tinned with a layer 14 of silver or a silver alloy e.g. 43-45% silver, 26-28% copper, 11-15% zinc, 14-16% cadmium, 0.8-1.2% phosphorus. The tip 10 is half filled with an aluminium-base brazing alloy, e.g. 87% aluminium, 13% silicon, and is heated to 550‹C. to fuse the alloy. A vibration transmitting member 18, Fig. 3, is inserted in the tip 10 and vibrated at about 20,000 cycles per second and the brazing alloy forms a coating 16 on the layer 14. The support member 12, Fig. 2, which may be an alloy of at least 90% aluminium with one or more zinc, magnesium, manganese, copper, silicon, iron or chromium, e.g. 97.9% aluminium, 1.0% magnesium, 0.6% silicon, 0.25% chromium, 0.25% copper, is provided with a coating 16 of the aluminium brazing alloy by heating to 550‹C. and vibrating at about 20,000 cycles per second. The tip 10 and member 12 are pressed together and cooled to complete the joint.