Simulation of weld pool dynamics in the stationary pulsed gas metal arc welding process and final weld shape

The pulsed gas metal arc welding (GMAW-P) process was modeled numerically using a code based on the volume of fluid (VOF) technique, chosen primarily for its ability to accurately calculate the shape and motion of free fluid surfaces, which is needed for subsequent study of welding phenomena such as bead hump formation, incomplete fusion in narrow groove welds, and weld toe geometry. According to the mathematical models with parameters obtained from analysis of high-speed video images and data acquisition (DAQ) system, GMAW-P was simulated and then validated by comparison of measured and predicted weld deposit geometry, transient radius, and temperature history. Based on the weld simulation parameters, a parametric study of weld simulation was performed to demonstrate and understand the effectiveness of individual simulation parameters on heat and fluid flow in the molten weld pool and the final configuration of stationary welds. Constricted current density drastically increased the weld penetration and decreased the weld radius, primarily by reducing the convexity of the weld deposit and promoting heat transfer to the bottom of the weld pool. Conversely, decreased arc force and increased arc pressure radius both decreased the weld penetration for the same reason. Based on the understanding of weld pool spreading, GMAW-P was simulated with an additional heat source to demonstrate the utility of the simulation in predicting final weld shape in complex welding situations.