Three Ways of Inhibition of Porosity in Laser Welding of Aluminum Alloy

【Summary Description】 1. background introduction Laser welding aluminum alloy is a common connection method, because of its high energy density, high accuracy, small heat affected zone and other advantages, widely used in aviation, automobile, 3C manufacturing and other fields. However, the porosity problem generated in the process of laser welding of aluminum alloy has always been a key factor affecting the welding quality. The presence of pores will reduce the strength and corrosion resistance of the welded joint, thereby affecting the performance and service life of the product. Therefore, how to effectively suppress the porosity problem in laser welding aluminum alloy has become an urgent problem to be solved. 2. three ways to inhibit stomata 1. Optimization of welding parameters Welding parameters include laser power, scanning speed, beam mode, shielding gas type and flow rate. These parameters have an important influence on the behavior of the molten pool in the laser welding process, and then affect the generation of pores. Optimizing these parameters can effectively inhibit the generation of stomata. Specifically, the best laser power and scanning speed can be found by experimenting with different parameter combinations to obtain the best penetration and width. At the same time, selecting the appropriate type and flow rate of the protective gas can reduce the interference of the gas, thereby reducing the generation of pores. 2. Preheated aluminum alloy plate Preheating aluminum alloy plate can reduce the surface tension of the plate and reduce the generation of pores. Before laser welding, the aluminum alloy sheet can be properly preheated to make the surface temperature of the sheet reach a certain level, thereby reducing the influence of surface tension and making it easier for the gas to escape the molten pool. At the same time, preheating can also reduce the width of the heat affected zone and reduce the risk of welding cracks. 3. Use suitable filling materials The filling material can protect the molten pool, absorb gas and improve the metallurgical conditions of the molten pool in the laser welding process, thereby reducing the generation of pores. Suitable filler materials should have good wettability with the aluminum alloy, corrosion resistance and high temperature stability. Commonly used filling materials include pure aluminum wire, aluminum silicon alloy wire, etc. When using filling materials, attention should be paid to controlling the filling amount. Excessive filling materials may affect the quality of laser welding. 3. experimental results and analysis The effectiveness of the above three methods is verified by experiments. The experimental results show that optimizing the welding parameters can effectively reduce the generation of pores, but the stability and repeatability of the parameters should be paid attention to. Preheating aluminum alloy plate can effectively reduce the generation of pores, but the preheating temperature and time should be paid attention to to avoid the expansion of heat affected zone and the overheating of the plate. 4. Conclusion In summary, optimizing welding parameters, preheating aluminum alloy plates and using appropriate filler materials are three effective ways to suppress the porosity problem in laser welding aluminum alloys. In practical application, the appropriate method should be selected according to the specific working conditions and product requirements to improve the quality and reliability of laser welding aluminum alloy. At the same time, it is necessary to continuously study and explore new technologies and methods to deal with new problems and challenges in the laser welding process.

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