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Difficulties in the application of laser welding technology in red copper welding

Addtime:2021-11-23 Browse times:822

Now, in industrial production and manufacturing, the consumption of non-ferrous metals, red copper ranks second, only second to aluminum. Red copper is widely used in construction industry, electrical equipment, machinery manufacturing and other industries. Red copper has excellent conductivity, thermal conductivity and excellent plasticity, which is convenient for hot pressing and cold pressure processing. With the continuous improvement of production demand, the use of red copper has been gradually expanded.
Common problems in red copper welding:
(1) Difficult fusion and variability: This is because the thermal conductivity of red copper is relatively large, the heat transfer speed during electric welding is very fast, and the heat affected zone of all weldments is also large, so it is difficult to fuse the data together; Because the linear expansion coefficient of red copper is large, when electric welding is heated, improper clamping force of fixture will deform the data.
(2) Prone to blowholes: another important problem in red copper welding is blowholes, especially in deep penetration welding. The occurrence of pores is mainly caused by two situations, one is the diffusive pores that can occur directly due to the dissolution of hydrogen in red copper, and the other is the reaction pores caused by redox reaction.
terms of settlement:
At room temperature, the absorptivity of red copper to infrared laser is about 5%, and after heating to the melting point, the absorptivity can reach about 20%. In order to realize the laser deep penetration welding of red copper, it is necessary to improve the laser power density.
The high-power laser is used to cooperate with the swing electric welding joint. During deep penetration electric welding, the beam is used to stir the molten pool and expand the keyhole, which is conducive to gas overflow, making the electric welding process more stable, less spatter and fewer micro pores after welding.
Welding skills:
(1) During electric welding, the angle of the welding joint is inclined to avoid long-term retroreflection damage to the laser.
(2) The laser power must reach the absorption value of red copper to avoid light reflection.
(3) The energy density of laser with small core diameter is easier to reach the absorption value of red copper than convergence.
(4) Swing welding can improve the surface quality of electric welding.