Numerical simulation and experiment for the dynamic behavior of molten pool in ultrasonic-assisted MIG welding

A three-dimensional (3D) transient numerical model that considers droplet impact, liquid metal oscillation, and dynamic variations in arc pressure is developed to explore the effect of ultrasonic waves on the behavior of molten pools in ultrasonic-assisted metal inert gas welding (U-MIG). The heat transfer and fluid flow of the U-MIG welding pool and the keyhole forming process are numerically simulated. The thermal field and flow field in the hybrid weld pool, as well as the form and size of the molten pool, were quantitatively analyzed. Simultaneously, the effect of ultrasonic on the welding pool is investigated by comparing it to the conventional metal inert gas welding (MIG) pool. The simulation results closely match the experimental results, verifying the model's validity and the accuracy of the relevant conclusions. This investigation defines the effect of ultrasonic on the temperature field and fluid flow of the U-MIG welding pool, and it sets the foundation for optimizing and applying the ultrasonic hybrid welding process.