Micro melting soldering method of argon-shielded tungsten arc welding for thick plate of red copper without warming-up

Abstract

The invention discloses a non-preheating tungsten argon arc welding micro-melt brazing method for thick-walled red copper, which relates to the improvement of the thick-walled red copper plate welding method. The first stage of the present invention adopts argon tungsten arc welding and arc brazing to fill the weld seam, heats the bottom of the groove of the parent metal with an electric arc, fills the welding wire without swinging, and the height of the filled weld seam is 1 / 3 of the thickness of the copper plate ; In the second stage, heating and remelting the filler metal in the first stage without filling the welding wire, and using an electric arc to stir up the molten metal liquid along the side of the groove until it reaches the top of the groove, and stay for 0.5-1s. After the slight melting occurs here, the arc moves downward again, so that this side forms a micro-melt layer mixed with the solder and the base metal, and uses the same method to make the corresponding groove on the other side form a micro-melt layer, and so on. Advance forward; the third stage uses double-point wire feeding to quickly fill the welding wire to form a micro-melting brazing seam. The invention has the advantages of no need for preheating for welding thick plate red copper, simple welding operation, beautiful welding seam shape and high welding quality.

Description

Technical field: [0001] The invention relates to an improvement in the welding method of thick-walled red copper plates. Background technique: [0002] The plasticity and strength of red copper decrease significantly between 400-700℃, melting welding of red copper (such as gas welding, manual arc welding, TIG welding, MIG welding, electron beam welding, etc.), brazing (flame brazing, TIG brazing, etc.) There are still some problems with other methods, such as gas fusion welding: it is more suitable for the repair of thin copper plates, copper parts or the welding of unimportant structures. There are many problems in the welding of thick-walled copper parts: (1) The preheating temperature is high (600-700℃), and the welding process should be continuous. The heating time is long, the input heat capacity is large, the welding heat-affected zone is large, the structure and performance changes greatly, and the working conditions of the workers are very bad. (2) The protective effect o...

AI Technical Summary

Problems solved by technology

There are many problems in the welding of thick-walled copper parts: (1) The preheating temperature is high (600-700 ° C), and the welding process should be carried out continuously

The heating time is long, the input heat capacity is large, the welding heat-affected zone is large, the structure and performance change greatly, and the working conditions of the workers are very bad.

(2) The protective effect of gas welding is not good

(3) The welding seam is poorly formed, easily deformed, prone to pores, unfused, cracks and other defects

The disadvantages are: the welding temperature is high, the working conditions of the workers are very bad, the heating temperature is difficult to control during manual operation, welding requires multiple people to work at the same time, and the technical requirements for the workers are high; the input heat capacity is large, the welding heat-affected zone is large, and the organization There is a large change in performance; flux is used, post-weld cleaning is required, and the strength of the joint is low

But the main problem in copper welding is high preheating temperature and poor welding quality

(1) The welding process is complicated: the preheating temperature (500-600°C) before welding is high, and the continuous welding process must be ensured

The high temperature residence time in the welding area is long, the input heat capacity is large, and the working conditions of the workers are very harsh

At the same time, the range of heat-affected zone is large, and the structure and joint performance change greatly.

(2) Severe evaporation of alloying elements: the weld contains high hydrogen and oxygen content, serious zinc evaporation, prone to pores, cracks and other defects

(3) Unstable welding quality, poor weld formation, and low joint strength

Its disadvantages are embodied as follows: (1) The input heat capacity is large, and the working conditions of workers are very bad

Moreover, the heat-affected zone range is large, the structure and joint performance change greatly, the joint strength is seriously damaged, and the production efficiency is low.

(2) Affected by large welding current and fast welding speed, it is difficult for the diffused hydrogen dissolved in the molten pool to overflow, and it is easy to form defects such as pores, cracks, incomplete fusion, and incomplete penetration

But there will also be many problems: For example, when the thick-walled copper is welded, the molten metal splashes due to the impact of the electron beam, resulting in deterioration of the weld shape.

However, it must be preheated at 600-700°C, and it is very sensitive to oxygen. When welding copper with insufficient deoxidation, the weld will have more pores and lower strength.

At the same time, the guiding significance for thin plate welding is not strong. When welding thin plates, the stability of the molten pool is poor, and welding quality problems such as overheating and collapse of the molten pool are prone to occur.

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