A dynamic welding heat source model in pulsed current gas tungsten arc welding

In pulsed current gas tungsten arc welding (PCGTAW), the peak current is generally selected to give adequate penetration and bead contour, while the background current is set at a level sufficient to maintain a stable arc. It is well seen that the arc is bell-shaped during the peak pulse duration while not during the background duration. A dynamic welding heat source model was established according to the characteristic of PCGTAW, and better simulation results were obtained. •A dynamic welding heat source model is proposed.•The dynamic heat source model is time-dependent.•The dynamic heat source model in pulsed current GTAW is established.•The dynamic model can successfully predict the process of pulsed current GTAW.•The results computed by the dynamic model are more accurate in some case. A time-dependent welding heat source model, which is defined as the dynamic model, was established according to the characteristic of PCGTAW. The parabolic model was proposed to describe the heat flux distribution at the background times. The recommended Gaussian model was used at the peak times due to the bell-shaped temperature contour. The dynamic welding heat source was composed of these two models with a function of time. To assess the validity of the dynamic model, an experiment was conducted in which the pulsed current gas tungsten arc deposits on the plate. From the comparison of the experimental and the simulated values, it can be concluded that the dynamic heat source model, which uses the parabolic model at the background time, is more realistic and accurate under the same welding conditions.