At present, the consumption of non-ferrous metals in industrial manufacturing ranks second only to aluminum. Copper is widely used in the construction industry, electrical, machinery manufacturing and other industries. Copper has good electrical and thermal conductivity, excellent plasticity, easy hot pressing and cold pressure processing, with the continuous improvement of production demand, the application of copper has gradually been expanded.
Laser welding has the advantages of high energy density, less molten metal, narrow heat affected zone, high welding quality and high production efficiency, applied to copper welding can effectively improve production efficiency, and is gradually selected by more and more industries. However, due to the low absorption rate of the high inverse material on the fiber laser, the processing is also difficult, which also has more requirements for the laser light source.
Problems prone to copper welding
(1) Difficult fusion and variability: Because the thermal conductivity of copper is relatively large, the heat transfer speed during welding is very fast, and the overall heat-affected zone of the welding part is also large, it is difficult to fuse the material together. Due to the large coefficient of linear expansion of copper, when welding is heated, the improper clamping force of the fixture will cause the material to deform.
(2) Prone to porosity: Another important problem caused by copper welding is porosity, especially when deep penetration welding is more serious. The formation of pores is mainly caused by two situations, one is the diffusion porosity directly generated by hydrogen dissolved in copper, and the other is the reaction porosity caused by REDOX reaction.
The solution
(1)The absorption rate of red copper for infrared laser at room temperature is about 5%, and the absorption rate can reach about 20% after heating to the melting point. To achieve laser deep penetration welding of red copper, it is necessary to improve the laser power density.
(2)Using a high-power laser coupled with the swing welding head, the beam is used to stir the weld pool and expand the keyhole during deep penetration welding, which is beneficial to gas overflow, making the welding process more stable, less splashing and less micro-pores after welding.
Welding skills
(1) When welding, the Angle of the welding head is tilted to prevent long-term reflection damage to the laser.
(2) The power of the laser must reach the absorption value of copper to prevent light from being reflected.
(3) The energy density ratio of the laser's small core diameter makes it easy to reach the absorption value of copper.
(4) Swing welding can improve the surface quality of welding.
Xi'an Guosheng Laser Technology Co., Ltd. is a high-tech enterprise specializing in R&D, manufacturing and sales of automatic laser cladding machine, high-speed laser cladding machine, laser quenching machine, laser welding machine and laser 3D printing equipment. Our products are cost-effective and sold domestically and abroad. If you're interested in our products, please contact us at bob@gshenglaser.com.