Laser welding of aluminum alloy problem 1: low laser absorption rate of aluminum alloy
This problem is mainly due to the problem of aluminum alloy material. Due to the high initial reflectivity of aluminum alloy to laser beam and its high thermal conductivity, the absorption rate of aluminum alloy to laser before melting is very low. The solutions to this problem mainly include the following aspects:
1. Surface pretreatment of aluminum alloy materials. Such as sandpaper grinding, surface chemical etching, surface plating and other pretreatment measures commonly used in production. Increase the laser absorption rate of the material.
2. Reduce the spot size and increase the laser power density.
3. Change the welding structure so that the laser beam forms multiple reflections in the gap, which is convenient for laser welding of aluminum alloy.
Aluminum alloy laser welding problem 2: easy to produce pores and hot cracks
Pores and hot cracks will easily occur during laser welding of aluminum alloys. For this problem, the solutions mainly include the following aspects:
1. Adjusting the laser power waveform in the welding process can reduce the unstable collapse of pores, change the angle of laser beam irradiation and apply the effect of magnetic field in welding, and can also effectively control the pores generated during welding.
2. When using YAG laser, the pulse waveform can be adjusted to control the heat input, so as to reduce crystal cracks.
Aluminum alloy laser welding problem 3: the mechanical properties of welded joints decline
The burning loss of alloy elements in the welding process reduces the mechanical properties of aluminum alloy welded joints. The solutions to this problem mainly include the following aspects:
The mechanical properties of welded joints are caused by unstable pores produced by aluminum alloy welding. Aluminum alloy mainly includes Zn, Mg and al. During welding, the boiling point of aluminum is higher than that of the other two elements. Therefore, when welding aluminum alloy elements, some low boiling point alloy elements can be added, which is conducive to the formation of small holes and the firmness of welding.