Effect of Hybrid Laser Arc Welding on the Microstructure and Mechanical and Fracture Properties of 316L Sheet Welded Joints

To explore the influence of different welding modes on the properties of 316L thin-plate welded joints, a new type of laser arc compound gun head similar to a coaxial one was used in this experiment. A high-speed camera was used to record the welding process and analyze the droplet splash behavior of the molten pool. The microstructure, microhardness change, and tensile test results of welded joints under different welding modes were analyzed. The results showed that laser welding (LW) is more prone to molten pool splash than hybrid laser arc welding (HLAW). The HLAW pool area was significantly increased compared with that of LW. The HLAW joint microstructure was more uniform than that of LW, which can improve the microhardness of welded joints. HLAW improved the tensile properties of the joint, with the maximum tensile strength of the joint increasing from 433 to 533 MPa. This test can provide guidance for the HLAW process.