Study on the heat input regulation mechanism of compound excitation device and its influence on arc shape and penetration behavior in GTAW.

In order to realize the heat input regulation in the gas tungsten arc welding (GTAW) process, a novel compound excitation device consisting of a longitudinal magnetic field and a cusp magnetic field was developed in this paper. The magnetic field distribution law in the arc zone was analyzed under various excitation parameters of the device. Using 316L austenitic stainless steel as the base metal, the variation law of arc and weld penetration under different coupling excitation parameters was studied. The research reveals that the magnetic induction intensity in arc zone approximately conforms to the linear superposition law of two single magnetic fields. Under the compound excitation device, the welding arc is compressed while maintaining its deflection, causing its cross-section to change from circular to elliptical. Under the premise that the longitudinal excitation current maintains the arc deflection angle, an increase in cusp excitation current results in a decrease in weld width and arc bottom area, while increasing weld penetration, metal melting area, and arc voltage. These results indicate that the compound excitation device can effectively regulate the heat input distribution and arc heat flux density. [ABSTRACT FROM AUTHOR]