NUMERICAL SIMULATION OF TIG WELD POOL BEHAVIOR UNDER THE ACTION OF PULSED CURRENT

A mathematical model is established for simulating the TIG(Tungsten Inert Gas) weld pool behavior in pulsed TIG welding. It was analyzed how the pulsed current affects the fluid flow and heat transfer in a TIG weld pool and the pool geometry. The computed results show that the volume of weld pool is sensitive to the action of pulsed currellt, the gradiellt ofthe surface tension is the main driving force for the fluid flow in pulsed TIG weld pool, andthe fluid velocity field changes periodically with the pulsed current. The computer vision-basedexperiment system is used to measure the varying process of the weld pool width in a ptilsedcycle. The predicted weld pool width is in agreement with the measured one.