Connection structure of copper-aluminum composite pipe and copper pipe and welding method thereof

Abstract

The invention discloses a welding method of a connection structure of a copper-aluminum composite pipe and a copper pipe, comprising the flowing steps: firstly: a tail end of the copper pipe shaping a cup-shaped flared tube section (3); secondly: expanding a horn mouth (4) at an opening end of the cup-shaped flared tube section (3); thirdly sleeving a welding ring on the copper-aluminum composite pipe; fourthly inserting the copper-aluminum composite pipe into the cup-shaped flared tube section (3); fifthly heating at a heating part (10) and fusing the wielding ring, the welding flux flowing the horn mouth (4). The invention solves the problem that the aluminum tube of an inner layer is melted while the copper pipe of an outer layer is not heated enough when the welding part is directly heated in the prior art, and enables the temperature of the copper and the aluminum to meet the process demand.

Description

technical field [0001] The invention relates to the field of metal pipe fittings, in particular to a welding method for a connection structure between a copper-aluminum composite pipe and a copper pipe. Background technique [0002] Copper pipes have been used as the main material of connecting pipes in air conditioners, freezers, and refrigerator systems of the prior art (the average consumption of pipe fittings per product is 2 to 3 kilograms of copper). However, due to the continuous rise in the price of copper materials in recent years, the production costs of air conditioners, freezers, and refrigerators have increased rapidly. Therefore, the replacement of copper tubes for various components of household appliances is an inevitable trend in the development of household air conditioners. At present, the market price of copper continues to rise, while the market price of aluminum pipe materials is only about one-third of the current copper. If the pipe fittings in the ...

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Problems solved by technology

[0004] 1) if figure 2 It is a welded cup-shaped flared pipe section structure between copper and copper in the prior art, Figure 4 It is a schematic diagram of the welding and heating structure between copper and copper in the prior art. In the prior art, the welding heating part 7 of the cup-shaped flaring pipe section 5 is directly heated. As the heating temperature rises, the aluminum tube in the inner layer has been melted. However, the outer copper pipe and solder filling area 6 are not heated enough, resulting in extremely poor soldering effect

[0005] 2) Another disadvantage of the copper-aluminum composite pipe is that when the heating temperature exceeds 350 degrees, the joint surface of the copper layer and the aluminum layer begins to oxidize and detach, thereby reducing the pressure resistance and service life of the copper-aluminum composite pipe.

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