Study on Microstructure and Mechanical Properties of Dual Laser Symmetrical Synchronous Welded Joint of 30 mm Thick TA2

In order to improve the welding efficiency and welding precision of titanium alloy, the double laser synchronous symmetric welding is carry out on the double laser synchronous symmetric welding on the 30 mm thick TA2 titanium alloy test plate, and the joint forming quality, welding deformation, microstructure, mechanical properties and process performance of the welded joint are studied. It is found out that the welded joint of the 30 mm thick TA2 plate is good and silver-white, and that the welding deformation is small. The macrostructure of the joint is of blocks, and has no obvious defects. No columnar crystals lie through the weld. The microstructures of the weld line and heat-affected zone are of the jagged α phase, and the microstructures of the base material is of the fine equiaxial α phase. The grains in the heart of the weld line are coarser than those in the near-surface of the weld line. The overall hardness of the welded joint is lower than those of the near-surface and heart of the weld line. The yield strength of the near-surface and heart of the weld line is higher than that of the base material, and the plasticity lower than that of the base material. The near-surface zone and the heart zone have a big difference in impact properties. The bending specimens are qualified, and the welded joints have good process performance. This shows that the dual laser synchronous symmetric welding technology for the thick titanium alloy plate has high-precision and good engineering application prospects.