:: Artigo completo: https://doi.org/10.1007/s40194-022-01352-y
Abstract:
Strategies for wire feeding in the GTAW process have evolved considerably in the last few years with the development of new techniques and wire feed systems. Nowadays, the most advanced technologies make use of dynamic wire feeding techniques. In this context, the aim of this study was to analyze the pulsed dynamic wire feeding technique with a low insertion angle between the wire and the tungsten electrode, in order to characterize aspects of the GTAW process variant such as metal transfer, temperature distribution, and weld geometry. A setup of GTAW equipment (power source, wire feeder, and welding torch) was coupled to an anthropomorphic robot for the torch displacement, and pulsed welding current was used. A multiple output analysis was applied: electric signal acquisition, infrared thermography filming, high speed filming, and macrographic analysis. Results show that the variation of the frequency together with the wire feed system dynamics influence the metal transfer events. At frequencies of 5, 15, and 20 Hz, for instance, the intermittent bridge transfer was not synchronized with the current pulsation, but at 10 Hz the metal transfer was well defined and occurred at the same frequency as the welding current pulse. The results also show that a frequency variation does not influence the weld bead temperature distribution, but for the wire feeding in the background period series, the weld bead penetration was higher than the other series.
Key-words: Dynamic wire feeding; Oscillated wire feeding; Pulsed wire feeding; Automated GTAW; Low-angle wire insertion
Reference:
PIGOZZO, I.O.; E SILVA, R.H.G.; GALEAZZI, D. et al. Pulsed dynamic wire feeding with low insertion angle in GTAW process: a metal transfer characterization. Weld World (2022). https://doi.org/10.1007/s40194-022-01352-y