Abstract
Numerical simulation based on an incompressible smoothed particle hydrodynamics method was performed to clarify dominant factors of slag transfer and deposition processes in a metal active gas welding with a computational model which considered the effects of a shielding gas flow on a slag floating on a weld pool surface. As a result, the slags generated on the weld pool surface near the center of a heat source were transferred to the edge of the pool, which was similar to an experiment result. The slags stayed at the trailing region of the pool and then deposited on a weld bead. These simulated behaviors supported the validity of the present computational result. In order to identify the dominant factors of the slag behavior on the weld pool, numerical experiments were conducted with individually acting the forces due to the Marangoni effect, the shearing force, the Lorentz force, and the drag by the shielding gas flow. From the computational results, it was suggested that the shearing force and the drag due to the shielding gas were dominant near the center of the heat source, and the slag was transferred from the vicinity of the heat source to the end of the weld pool. On the other hand, it was clarified that the force due to the Marangoni effect was dominant in the trailing region of the weld pool, and consequently the slag was transferred from there to the front region in the welding direction.
