Theoretical and simulation analysis of the transient plasma characteristics of ultrahigh-frequency adjustable multipulse gas tungsten arc welding

Abstract The introduction of ultrahigh-frequency pulse gas tungsten arc welding has revolutionized the precision of heat input control in welding arcs, presenting new and promising research directions for welding processes. However, due to current limitations in imaging technology, only steady-state images of the arc under 100 kHz pulse current conditions can be captured, making it challenging to display instantaneous dynamics. This has led to a lack of in-depth studies on the arc morphology and characteristics of ultrahigh-frequency adjustable multipulse gas tungsten arc welding (UFMP-GTAW) at this frequency. To bridge this gap, a transient two-dimensional axisymmetric numerical simulation model for 100 kHz UFMP-GTAW was established in this paper, based on magnetohydrodynamics and the assumption of local thermal equilibrium. The model used Maxwell’s equations to simulate the physical behavior of the arc. A 100 kHz UFMP-GTAW arc model was generated and analyzed using simulation technology. The results show that the macroscopic morphology of the 100 kHz UFMP-GTAW arc obtained through simulation remains highly stable within a single-pulse cycle, which is consistent with the actual steady-state arc images. The high-intensity energy regions inside the arc exhibit regular droplet-like flows that migrate from the cathode to the anode. Variations in the current, temperature, and current density exhibit asynchronous characteristics. The peak and average values of parameters such as the arc temperature and current density have increased significantly. This method’s unique current waveform design and ultrahigh-frequency mechanism enable it to achieve a high-energy state of arc plasma at a lower average current level, which provides a reference for the precise control of welding quality and improves the welding energy utilization efficiency.