Arc Characteristics of Ultrasonic-Magnetic Coaxial Hybrid GTAW

Abstract

Ultrasonic-magnetic field coaxial hybrid GTAW(U-M-GTAW) is a new non-melting electrode welding method proposed by combining ultrasonic assisted GTAW(U-GTAW) and magnetic assisted GTAW(M-GTAW) on the regulation characteristics of the GTAW arc. U-M-GTAW introduces ultrasonic and magnetic field effects into GTAW to improve arc characteristics. The orthogonal experiment was designed to investigate the degree of influence of different process parameters on the arc. The degree of influence of ultrasonic power P, radiator height H, magnetic field current CW, welding current CW and tungsten electrode height HT on ΔL1 (degree of arc root diameter change), ΔL2 (degree of maximum diameter change) and ΔS (degree of area change) were analyzed. In the parameter range, P has the greatest degree of influence on ΔL1 and ΔL2. As all process parameters increase, L1 shows a tendency to decrease, indicating an increase in the compression of the arc root. ΔL2 with the increase in P and CW shows a trend of first decreasing and then increasing. ΔL2 with the increase in H decreases, indicating that the acoustic radiation force increases, the arc energy increases, and the dark region decreases. The magnetic field current increases, the bottom of the arc expands, and the height of the tungsten electrode increases, the arc dispersion and thus the difference between the dark and luminous regions at the bottom increases, resulting in ΔL2 with the increase in CM and HT increases. CW has the greatest degree of influence on ΔS. ΔS decreases and then increases as P and H increase, which indicates that the force on acoustic radiation increases and then decreases in the range. An increase in the magnetic field current increases the rotation of the arc, leading to an increase in the arc area. An increase in welding current leads to an increase in arc energy, expansion of the arc morphology, and an increase in ΔS. The tungsten electrode height increases, the arc diverges, the dark region increases, the luminous area decreases, and ΔS increases. Finally, combined with the analysis of ultrasonic field and magnetic field theory, changes in process parameters will affect the force of the arc and thus the arc morphology. The U-M-GTAW arc under the action of acoustic radiation force, the plasma flow is shifted in the direction of the arc axis, and the arc contraction, under the action of magnetic field force to generate circumferential current, the arc undergoes periodic rotation, which improves GTAW arc characteristics.