Copper-aluminum joint pressure welding technique

Abstract

The invention relates to a pressure welding technique of a copper and aluminum joint, which is characterized by steps of: the blanking of a copper pipe and an aluminum pipe, the removal of burr and the washing of the surface of the copper pipe with acid; welding: a welding machine, an upper clamping mould and a lower clamping mould are adjusted; the copper pipe and the aluminum pipe are respectively clamped between the upper clamping mould and the lower clamping mould, the two ports for welding are extruded out of the clamping mould, the ends of the copper pipe and the aluminum pipe to be welded are heated to the temperature of about 420 to 540 DEG C and applied with the upsetting force of 0.4 to 0.8Mpa so as to cause the close contact of the welding surface of the copper pipe and the welding surface of the aluminum pipe, radial plastic deformation is generated by pressure, metal flashes are formed and a welding line is formed by the closely contacted pure metals, therefore, the welding process is finished; detecting welding beadings, removing residues and external burr; leak-checking: detecting whether the welded pipe has leakage by an air pressure test; drying and leak-checking with helium. The invention has simple technique and can reduce production cost and enhance production efficiency; since the oxidized film of the contact surface of the copper pipe and the aluminum pipe are damaged and extruded during pressure-increasing and deforming, the welded joint can be purified with good welding quality, no leakage, no deformation and long service life.

Description

technical field [0001] The invention relates to a copper-aluminum joint pressure welding process. Background technique [0002] Since the melting point of copper is 1083 degrees Celsius and the melting point of aluminum is 660 degrees Celsius, an oxide film will naturally form on the surface of aluminum. Due to the cleanliness requirements of the refrigeration pipeline, this layer of oxide film cannot be removed by adding additives, and it is also difficult to remove by physical methods, and the melting point of this layer of oxide film is 2000 degrees Celsius. These three different melting points lead to Copper-aluminum welding is very easy to form a virtual weld or even fail to weld. The traditional copper-aluminum tube welding method is to use energy storage welding and friction welding. Copper-aluminum welding can also be realized by applying welding aids, but these methods can only complete the welding of copper-aluminum tubes above 1.0 mm; to reduce the wall thickness...

AI Technical Summary

Problems solved by technology

Due to the cleanliness requirements of the refrigeration pipeline, this layer of oxide film cannot be removed by adding additives, and it is also difficult to remove by physical methods, and the melting point of this layer of oxide film is 2000 degrees Celsius. These three different melting points lead to Copper-aluminum welding is very easy to form a false weld or even fail to weld

The traditional copper-aluminum tube welding method is to use energy storage welding and friction welding. Copper-aluminum welding can also be realized by applying welding aids, but these methods can only complete the welding of copper-aluminum tubes above 1.0 mm; to reduce the wall thickness will increase Weld seam leakage probability, this method cannot be applied to air-conditioning connecting pipes with a wall thickness of only 0.6-0.8mm, and its production process is complicated, production efficiency is low, and production cost is high

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