Temperature distribution characteristics of ultrahigh frequency adjustable multi-pulse GTAW arc

Abstract

To solve the problems of low penetration capability, slow welding speed, and low welding productivity of traditional gas tungsten arc welding (GTAW), the ultrahigh frequency adjustable multi-pulse GTAW (UFMP-GTAW) process was proposed. The welding frequency of this process could reach up to 100 kHz, and the current change rate reached 150 A/μs. By introducing an intermediate current stage into the pulse welding current waveform, multiple current pulses were generated within a single welding cycle, and the time and amplitude of each stage of the pulse waveform were adjustable. An experimental platform for UFMP-GTAW was established to capture ultrahigh frequency welding arcs at different frequencies, which were then compared with ultrahigh frequency ordinary pulse welding arcs. Under the same average current, the high-frequency effect generated by the ultrahigh frequency current gave the arc a compression characteristic, making the temperature distribution of the welding arc more concentrated. Among them, the welding arc of 100 kHz UFMP-GTAW had the most concentrated temperature distribution. Finally, welding tests were conducted on Q235 steel. The results show that the 100 kHz UFMP-GTAW process can compress the welding arc and achieve a larger weld penetration depth.

Keywords

• ultrahigh frequency welding
• arc temperature
• pulsed gtaw
• high-frequency pulse