School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;
Department of Mechanical Energy Engineering,Southern University of Science and Technology,Shenzhen 518055,China;
State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;
Weld pool surface; GTA welding; Bessel function; Oscillation mode; Geometric optics;