Abstract: A 3-D transient numerical model for TIG welding stainless steel has been developed to simulate full-penetrated weld pool dynamic behavior. It has been found that when the double-elliptic distribution modes of both heat flux and arc pressure are employed in the numerical simulation of weld pool geometry and surface deformation for moving TIG welding, the calculated results agree much better with the experimental measurements, compared with the predicted ones when Gaussian distribution modes are used. The dynamic development of deformation at top and bottom surfaces of weld pool is demonstrated, and the difference between the stationary TIG welding and moving TIG welding is analyzed. It provides theoretical basis and experimental data for precise modeling and intelligent control of moving TIG welding.

Key words: Double-elliptic distribution mode, Numerical simulation, Surface deformation, Weld pool geometry