Abstract
Recent developments in welding technology have focused on the advances of new variants and technique for existing processes, whereby the GTAW with Dynamic Wire Feeding (GTAW-DWF) stands out. The use of automated and more complex processes also demands better methods and more accurate tools for monitoring and controlling. Despite this demand, the relating few works available in the literature handle, mainly, with the influences of the dynamic wire feeding technique over the weld beads. The present work introduces a novel approach to monitor and characterize the GTAW process with dynamic wire feeding. By means of welding data acquisition and high-speed videography and data post-processing, the metal transfer, process stability and wire insertion position were evaluated. The coupled monitoring of the electrode-to-wire voltage and the wire feed speed proved to be an effective tool to accurately define and measure the metal transfer cycles. With the data post-processing algorithms, the metal transfer events in the dynamic wire feeding were characterized by parameters specifically inherent to the technique, such as volume of wire transferred per cycle, bridging time, molten pool elongation, wire dip into the molten pool, maximum and average forward/backward speeds and so on. Furthermore, electrical signals can also be used to monitor the wire insertion position. In this work, it could be established that the electrode-to-wire voltage varies with the electrode-to-wire distance and oscillation amplitude. Moreover, the behavior of electrical and wire feed speed signals also express process instabilities in the metal transfer such as wire stubbing, lack of filler metal and metal transfer irregularity. Abrupt increase or reduction rates of the acquired signals can express distinct phenomena, and the right interpretation can be used to predict or prevent instabilities enhancing the process robustness and reliability.
Keywords: Dynamic wire feeding; GTAW; Metal Transfer; Process Monitoring.
Referência:
PIGOZZO, I. O.; SILVA, R. H. G.; VIVIANI, A. B.. A novel monitoring and characterization approach of dynamic wire feeding in GTAW process. 77th IIW annual assembly, Rhodes, Greece, July 7–12, 2024