Currently, among the non-ferrous metals used in industrial manufacturing, red copper occupies second place, behind aluminum.
Related Reading: Ferrous vs Non-Ferrous Metals
Red copper is widely used in various sectors, including construction, electricity and machine manufacturing.
Red copper is valued for its superior conductivity and thermal conductivity, excellent malleability, and ease of processing through hot and cold pressing.
As production demands continue to evolve, the application of red copper has progressively expanded.
Laser welding offers numerous advantages such as high energy density, minimal molten metal, narrow heat-affected zone, superior welding quality and high production efficiency. When used for red copper welding, it can significantly increase production efficiency and is becoming more and more popular in different industries.
However, the low absorptivity of high antimaterial laser to fiber laser represents a challenge in processing such materials, requiring specific laser sources to meet the demand.
Common Problems When Welding Red Copper
(1) Difficult fusion and variability
Red copper has a high thermal conductivity, resulting in rapid heat transfer during welding and a large overall heat-affected zone of the weld. This makes it difficult to fuse the materials. Furthermore, due to its high coefficient of linear expansion, inadequate clamping force of the fixture during welding may cause the material to deform when heated.
(2) Prone to porosity
Porosity is a significant problem in red copper welding, particularly in deep penetration welding.
The formation of pores is mainly due to two conditions: one is the formation of diffusive pores that are generated by the direct dissolution of hydrogen in red copper, and the other is the formation of reactive pores caused by redox reactions.
Solutions
The absorptivity of red copper to the infrared laser is approximately 5% at room temperature. However, when heated close to its melting point, the absorptivity increases to about 20%.
To achieve laser deep penetration welding of red copper, it is essential to increase the laser power density. This can be done using a high power laser in combination with an oscillating welding joint. Stirring the molten pool and expanding the keyhole with the light beam during deep penetration welding helps with gas overflow, ensures a more stable welding process, and reduces spatter and micropore formation after welding.
Welding Skills:
(1) During welding, the angle of the welded joint is tilted to avoid long-term backreflection that may damage the laser.
(2) The laser power must reach the absorption value of red copper to avoid light reflection.
(3) The absorption value of red copper can be easily achieved by increasing the concentration of energy density ratio with a small core diameter.
(4) Oscillating welding can improve the welding surface quality.
