JIANG Yan, MA Guolong, MA Yin, et al.Study on Laser-MIG Hybrid Welding Characteristics of Typical Joints of Aluminum Alloy Carbody for High Speed Train[J].Electric Welding Machine, 2022, 52(10): 1-8. DOI： 10.7512/j.issn.1001-2303.2022.10.01.
Study on Laser-MIG Hybrid Welding Characteristics of Typical Joints of Aluminum Alloy Carbody for High Speed Train
In order to expand the application of laser-MIG hybrid welding in the manufacturing of aluminum alloy car body profiles for high-speed train, laser-MIG hybrid welding experiments were carried out to weld typical joint structure of traditional 3 mm thick A6N01S-T5 aluminum alloy for high speed train in this work. The welding parameters were optimized, structure and property of joints were analyzed. The adaptability of the laser-MIG hybrid welding was also studied. The experimental results show that the weld is well formed and no porosity defects with the optimal welding parameters. The microstructure in the weld center is dendritic as cast structure, and near the bond line is columnar crystal structure. The bond zone is narrow, but the grain is slightly coarse in the heat-affected zone. The hardness of weld metal zone is lower than that of the base metal zone, and the minimum hardness is located in the heat-affected zone near the bond line. The average tensile strength of the joints with the optimal welding parameters is 204.6 MPa, reaching 83.5% of the base metal. The tensile sample fractures near the bond line and the fracture morphology showes typical plastic fracture characteristics. And the joint has good bending performance. The optimal welding parameters has good commonality when the assembled gap less than 1.0 mm, the weld formation and joint tensile strength are fine. The weld formation and joint tensile strength are still good with the optimized welding parameters when the assembled gap increases to 1.5 mm. The research results prove that the laser-MIG hybrid welding has good feasibility and adaptability in typical joints of aluminum alloy carbody for high speed train.
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