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

Abstract

A slight-smelting TIG torch-brazing method for thick red copper plate without preheating includes such steps as using electric arc to heating the bottom of groove while filling the welding wire until the height of the filled seam is 1 / 3 of thickness of red copper plate, heating to resmelt the filled metal while blowing the molten metal up to the top of groove for slightly smelting it, and fastly feeding the welding wire to both slopes of groove while TIG arc welding.

Description

Technical field: [0001] The invention relates to an improvement of a welding method for thick-walled red copper plates. Background technique: [0002] The plasticity and strength of red copper decrease significantly between 400-700°C, and the melting welding (such as gas welding, manual arc welding, TIG welding, MIG welding, electron beam welding, etc.) and brazing (flame brazing, TIG brazing, etc.) There are still some problems in other methods, such as gas fusion welding: it is more suitable for the repair of thin copper plates and 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 ° 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 workers are very bad. (2) The pr...

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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