Abstract: The T-shaped welding process of 5754 aluminum alloy with 2mm thickness was carried out by melting inert gas shielded welding. The changes of macroscopic morphology, microstructure and microhardness of welded joint were analyzed by welding current, voltage and speed. The results show that increasing the welding current, voltage or reducing the welding speed will increase the welding heat input, increase the weld penetration or even produce penetration phenomenon, and lead to uneven coaling or cracking of the weld and heat affected zone, which will reduce the hardness of most areas of the welded joint, thereby reducing the welding quality. However, when the heat input is low, the welded joint will produce non-fusion phenomenon and a large number of pores, so that the joint hardness is reduced and the welding performance is affected. Through the test analysis, the joint hardness distribution is uniform, the macroscopic defects are significantly reduced, the micro structure is refined, and the comprehensive performance is improved after the optimized process parameters are used for welding.
