Views: 2 Author: hu Publish Time: 2021-08-31 Origin: dapeng
As the automotive industry continues to grow, pure electric vehicles and fuel cell vehicles will jointly dominate the future development of China's new energy vehicle market. The lightweight of electric vehicles and the extensive use of fuel cells will inevitably involve more and more aluminum alloy welding processes. Aluminum alloy has good physical, chemical and mechanical properties and is an important light metal material in industrial production. At present, the connection of aluminum alloy materials is mainly welded by two traditional welding processes of inert gas tungsten electrode shielded welding and molten electrode inert gas shielded welding. These two welding processes are slow in welding speed, low in production efficiency, and large in welding heat input, which makes the welding deformation of aluminum alloy larger, and at the same time, the grains at the welded joints are coarse, resulting in poor product quality. As a heat source with high energy density, laser has a faster welding speed and a smaller heat input, so the welding distortion is small and the quality of the obtained product is also superior.
1.3 Experimental method
Use an acetone solution ultrasonic cleaner for 25 minutes before welding to remove oil and other impurities on the surface of the sample. Continuous laser and pulsed laser are used to weld the samples respectively. After the welding is completed, the surface morphology of the weld is observed in a precision measuring microscope.
1.4 Experimental parameters
Because aluminum alloy has high reflectivity to laser, in order to prevent back reflection from burning the laser, the welding head is tilted by 5 degrees. When continuous laser welding, the three process parameters of defocus, laser output power and welding speed are optimized to obtain the best process parameters of continuous laser welding; at the same time, when welding with pulsed laser, the pulse waveform is square. Wave, the pulse energy is optimized to obtain the best process parameters of pulse laser welding. The optimized welding process parameters are shown in Table 1 and Table 2.
Table 1: Continuous laser welding parameter optimization
Table 2: Optimization of pulse laser welding parameters