Application research of aluminum alloy laser welding structure

Since the 1990s, with the development of science and technology, the emergence of high-power high-brightness lasers, laser welding technology integration, intelligence, flexibility and diversification of the development of increasingly mature, laser welding at home and abroad in the application of aluminum alloy structure in various fields of the application of more and more attention.battery pilot line At present, some of China's automobile manufacturers have adopted laser welding technology in some new models. With the development of laser welding technology for aluminum alloy thick plate, laser welding will become the main welding method for future armored vehicle structure.

In order to achieve lightweight manufacturing, the application and research of laser welding of aluminum alloy sandwich structure is a research hotspot for the manufacturing of ship and high-speed train structure.laser welding machine for lithium ion batteries Aluminum alloy is an important metal structural material in aerospace structures, so developed countries such as Japan, the United States, the United Kingdom, Germany and other countries attach great importance to the research of aluminum alloy laser welding technology.

With the development of fiber laser welding production technology, the current advanced management of the aviation manufacturing field has been fiber laser welding and laser arc composite welding construction technology as the focus of the aluminum alloy welding process technology,ESS lithium battery machine especially thick plate welding and dissimilar metal welding, such as the U.S. NALI project is mainly for the civil aircraft and JSF aircraft engine combustion chamber structural design is actively carrying out fiber laser welding and laser Arc composite welding engineering technology research.

Aluminum laser welding characteristics

Compared with the traditional melt welding, aluminum alloy laser welding has the advantages of concentrated heating, large weld depth to width ratio, small deformation of the welded structure, etc.: 1.

1. Laser focusing spot diameter of small problems lead to different workpiece welding assembly precision can require high, usually need to assembly gap, the amount of misalignment needs to be less than 0.1mm or 10% of the plate thickness, increasing the implementation of a very complex system of three-dimensional weld welding product structure management difficulties;

2. Due to the aluminum alloy at room temperature to the laser reflectivity of up to 90%, aluminum alloy laser deep fusion welding on the laser power requirements are very high. Research on laser welding of aluminum alloy thin plate shows that the laser deep fusion welding of aluminum alloy depends on the double threshold of laser power density and line energy, which together govern the behavior of the molten pool in the welding process and ultimately reflect the forming characteristics of the weld. The process optimization of full penetration weld can be evaluated by the back-to-width ratio of the weld forming characteristic parameters.

3. Aluminum alloy melting point is low, liquid metal mobility is good, strong metal vaporization under the action of a strong laser, the formation of metal vapor/photoplasma cloud in the welding process is related to the effect of small holes, which affects the absorption of laser energy by aluminum alloy, resulting in an unstable deep-melt welding process, and the weld is prone to porosity, surface collapse, biting edges and other defects;.

4. Laser welding heating and cooling speed, weld hardness is higher than the arc. However, due to the burning of alloying elements during laser welding of aluminum alloys, which affects the alloy strengthening effect, there is still a softening problem in the aluminum alloy weld, which reduces the strength of aluminum alloy welded joints. Therefore, the main problem of aluminum alloy laser welding is to control welding defects and improve the performance of welded joints.