Simulating molten pool features of shipbuilding steel subjected to submerged arc welding

Submerged arc welding process has been simulated to investigate the molten pool features of EH36 shipbuilding steel. One case only involved the surface tension model, and another one involved both the surface tension model and the interface tension model. The role of interface tension during welding is revealed, and the evolution of molten pool morphology is understood by comparing the surface temperature distribution, surface tension and interface tension distribution, and the streamline of the molten pool for the two cases. When the interface tension model is disregarded, a flow conducive to the outward expansion is formed in the surface area of the molten pool, resulting in a small weld depth-to-width ratio. After applying the interface tension model, the expanding outward flow is restrained, which leads to a deep penetration morphology with a large weld depth-to-width ratio due to the inward flow governed by the Marangoni forces. The simulation results involving the interface tension model have been verified with satisfactory predictability.