GB568453A - An improved method of welding metal bodies - Google Patents

Abstract

568,453. Thermo-aluminic processes. SOC. ANON. POUR L'INDUSTRIE DE L'ALUMINIUM. Sept. 24, 1943, No. 15719. Convention date, Sept. 30, 1942. [Class 83 (iv)] [Also in Group II] In welding bodies of light metals such as magnesium or aluminium or their alloys, or bodies of brass or a body of copper to a body of aluminium, the assembled parts are surrounded by an exothermic mass which is then caused to react without allowing the molten products to flow out of the mass, the heat supplied by the reaction welding the parts together. Rods, profile sections, tubes, cables or T-pieces for electric conductors of aluminium may thus be joined. The ends of the parts 1, 2 may be separated by an aluminium centring ring 6 which may form part of the joint which is effected by fusion or by upsetting. The parts are enclosed in a briquette 3 of the reaction mixture which may contain excess of iron oxides or consist of 23 per cent magnesium, 23 per cent of magnesium oxide and 54 per cent of small scale so as to prevent the molten iron formed by the reaction from running out of the mixture, or the mixture for this purpose may consist of a thermo-magnesium mixture with excess of iron oxide, or a mixture such as 20-30 per cent Mg, 2-7 per cent Al and 67-78 per cent small scale or 24-26 per cent Mg, 3-5 per cent A1 and 69-73 per cent small scale. Between the briquette and the parts 1, 2 may be placed a tube 4, which may be of aluminium so as to form part of the joint or may be of ceramic material or of a metal of higher melting point such as iron, with a folded joint so that it can be removed after welding. The briquette is surrounded by a cardboard tube 10 and is provided with end covers 11, any interstices into which moisture could penetrate being sealed by paraffin. The briquette may be ignited by a mixture 8 of potassium chlorate, aluminium powder, magnesium powder and sulphur provided with a tear-off strip 9. When welding tubes or hollow cables, the hollow may be provided with a tube of infusible material or of a metal of higher melting point. An intermediate piece, such as 6, may be placed near the joint instead of in the joint, so that it is melted during welding and runs into the joint. In cases where the parts cannot be pressed together, as in welding bus-bars, one or more intermediate pieces are placed between the parts after they soften or begin to melt, so that they serve, to effect the upsetting. In normal cases, the parts are secured between sets of clamps which are under spring pressure for effecting the upsetting. The upsetting device is light enough to be suspended on overhead aluminium cables during the welding thereof.