Copper and aluminium connecting tubes with hard sleeve and method for making same

Abstract

The invention relates to a Cu-Al connecting pipe provided with a rigid sleeve and a preparation method thereof. The welding head of a Cu pipe is provided with a conical solder side provided with a straight tubular guiding part; the external diameter of the guiding part is slightly less than the internal diameter of an Al pipe; the conical solder side of the Cu pipe and the internal wall of the Al pipe form direct chemical bond connection; the external sleeve of the Cu-Al connecting pipe is sleeved by a small section of a rigid sleeve; when in use, the rigid sleeve can prevent the cracking of the Al pipe caused by the bending of a butt joint and prevent the breaking of welding joint of the Al pipe or the Cu pipe in the sleeve. The rigid sleeve can avoid severe accidents such as the desquamating of welding joint and cracking of Al pipe near the joint and the like, prevents the generation of external splashing matter outside the welding joint, simplifies the process, relieves the destabilized deformation generated when the thin walled Cu pipe bears high pressure in the axial direction, increases the length of no-eutectic tissue welding seam, and is especially applicable to the welding of thin walled Al pipe and thin walled Au pipe.

Description

technical field [0001] The invention relates to a dissimilar metal connecting pipe, especially a copper-aluminum connecting pipe. [0002] The present invention also relates to a preparation method of the above-mentioned copper-aluminum connecting pipe. Background technique [0003] In recent years, due to the continuous rise in copper prices, the technological progress of replacing copper with aluminum and the market application scope of related industries have been promoted. my country is relatively short of copper resources and relatively rich in aluminum resources. At present, a large number of copper pipes are used in the refrigeration industry. It has become a very important issue to reduce manufacturing costs by replacing copper with aluminum. However, most of the copper tubes involved in the refrigeration industry have a wall thickness of less than 1.0 mm; due to the special advantages of copper tubes in the production and processing of refrigeration pipelines, it i...

AI Technical Summary

Problems solved by technology

Although methods such as energy storage welding and friction welding of plane butt joints can reduce the eutectic structure of copper-aluminum pipe welds through the top force before the end of welding, the joint structure determines that this process can only be used for thick-walled pipes with a wall thickness greater than 1.25mm. The welding of copper-aluminum pipe; can not be used for the welding of thin-walled copper-aluminum pipe involved in the present invention

The socket joint where the copper tube is inserted into the aluminum tube is suitable for welding thin-walled copper-aluminum tubes. It is welded by high-frequency welding and brazing methods. Due to unfavorable factors such as reactive pores, copper-aluminum eutectic structure, and potential corrosion hazards, it cannot be welded. It is very difficult to realize the chemical bonding of copper and aluminum, and it is very difficult to realize mass production; after adopting the resistance pressure composite welding method, the bending resistance of copper and aluminum joints is obviously insufficient, and these technical defects hinder the application of aluminum tubes in the refrigeration industry

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