Non preheating argon arc fusion welding method for thick red copper plate

Abstract

An argon arc welding technique for welding thick red copper plate without preheating includes such steps as making a groove on the red copper plate, putting the ceramic pad or refractory material under the groove, regulating welding current, heating the groove of mother material, filling alloy flux for mutual dissolving between the metal and filled alloy, moving the arc forward, and repeating the said relative steps until whole seam is welded. Its advantages are less influence to mother material, high speed, and high toughness of welded seam.

Description

Technical field: [0001] The invention relates to an improvement of a welding method for thick-walled red copper plates. Background technique: [0002] Copper and copper alloys are widely used in electric power, petroleum, chemical industry, machinery, defense industry, light industry, agriculture and other sectors, and its use is second only to steel and aluminum. Since the plasticity and strength of red copper decrease significantly between 400 and 700°C, it can be used in melting welding (such as gas welding, manual arc welding, TIG welding, MIG welding, electron beam welding, etc.), brazing (flame brazing, TIG brazing) of red copper. Welding, etc.) and other methods have found that there are still some problems in the welding of red copper, such as: [0003] Gas fusion welding: more suitable for thin copper parts, repair of copper parts or welding of unimportant structures. There are many problems in the welding of thick-walled copper parts: (1) The preheating temperatu...

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, and the structure And the performance changes greatly, and the working conditions of the workers are very bad; (2) The protective effect of gas welding is not good, the reducing atmosphere in the air invades the weld, and the oxides in copper are reduced to form a low melting point eutectic (Cu +Cu 2 O) Distributed at the grain boundary, which increases the tendency of thermal cracks; (3) The weld is poorly formed, easy to deform, and prone to defects such as pores, incomplete fusion, and cracks

The disadvantages are: (1) 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; (2) The input heat capacity is large, and the welding heat The affected area is large, and the structure and performance change greatly; (3) flux is used, which needs to be cleaned after welding, and the joint strength is low

But there will also be many problems: (1) 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, especially when the thick-walled copper tube is welded, because its energy density is particularly large, The test piece is very easy to burn through, the copper water flows, and the weld cannot be formed; (2) The electron beam welding equipment is expensive, and the welding is required to be carried out in a vacuum, and the working environment is limited by the size of the vacuum chamber

However, this method must be preheated at 600-700°C, which is very sensitive to oxygen elements. While the welding deoxidation is insufficient, the weld seam has 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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