Three-dimensional analysis of molten pool in GMA-laser hybrid welding

A computational analysis of a molten pool in laser-GMA hybrid welding is achieved including free-surface tracking using the well-known volume of fluid (VOF) method. The suggested three-dimensional transient numerical model includes all known analytical key features of arc welding including electromagnetic force, buoyancy, and arc pressure. In addition to the basic GTA model, molten droplets are artificially generated and allowed to fall down to the pool to cover the GMAW process. A keyhole analysis model is merged to a GMAW simulation model with the assumption that the interaction between the laser and the arc is negligible for convenience. The keyhole model is established on a unique phenomena that includes multiple reflections, Fresnel absorption model, and the recoil pressure in laser welding apart from the inverse Bremsstrahlung absorption. The result shows the flow patterns of the molten pool in GMA-laser hybrid welding, and they are compared to previously reported observation results. The molten flow at the bottom of the keyhole rises up slowly, and therefore a vortex can be observed throughout the molten pool. However, the flow pattern became increasingly complicated. The flow of the keyhole root is split into three main streams, and one stream is continuously maintained in the vortex.