method for welding tubular parts and electric parts ajournees, device for its implementation and its application in the manufacture of heat exchangers

摘要

1491914 Welding by pressure DES USINES CHAUSSON SA 6 March 1975 [19 March 1974] 9474/75 Heading B3R A method of welding a tubular part 1 to a part 2, Fig. 2, having an opening aligned with the tubular part, the parts having mutually engaging portions bearing one against the other, comprises engaging an electrically conducting member 4 with one of the parts near the mutually engaging portions, passing a current through the member to heat it, causing relative displacement between the member and the parts over a limited distance to apply a pressure during welding to the mutually engaging portions, heat being simultaneously conducted to the parts from the member to cause welding together of the portions. The tubular part 1 and the part 2, such as a plate, may be of aluminium, aluminium alloy, copper, brass or steel, for example, stainless steel. The member 4 may be of graphite and has a neck for engaging the opening and tube 1 and a tapered portion 4b. The member is mounted by copper terminals 9, which are connected to an electrical source, on an insulated base 8 having columns 10 supporting a plate 11 which through nuts 13 applies pressure to the tube 1 by way of a clamp 11. A current passed through the members 4 causes heating thereof such that welding takes place between the parts, the relative movement between the parts during welding being limited by stops 13a on the columns 10. The tapered portion of the member causes a swaging at the welded joint. In another embodiment for welding a tube 25, Fig. 4, to an upstanding flange 24 of a plate 23, the member 26 has the shape of a ring with a tapered inner wall 27 to effect the swaging. The member is shaped at 28 to increase its resistance. A mandrel 29 placed within the tube may be connected to one of the terminals of the member to increase the welding efficiency and prevent deformation of the tube. The members may be split to facilitate fitting around the tube. A number of tubes may be welded simultaneously to the plate of a heat exchanger using a single heating member. The welding may be effected in a neutral or reducing atmosphere containing nitrogen or argon.