Viabilidade operacional de emprego do processo HW-GMAW em aços

Abstract

This study investigated the operational viability of the HW-GMAW variant of the GMAW process in steels welding compared to the CW-GMAW and GMAW processes. This study has been conducted in the two phases. In the phase I beads on plate welding were performed on ASTM -131 grade A rating steel, varying the additional wire feed rate by 40%, 80% and 120% for CW and HW and current at 40 A and 80 A. In phase II an AISI 1020 classification steel were used, varying the additional wire rate by 20% and 100% HW and the current in 70 A.The statistical tools used considered that results were affected by current and wire feed rate (phase I) and the polarity, feed rate of wire and torch displacement orientation (phase II). Phase I results showed that the HW-GMAW process increased depth of penetration by 27% over the CW-GMAW process at up to 32% lower dilution levels over the GMAW when the feed rate was 120%. In the phase II, the capture of high-speed image in the study of electric arc dynamics suggest that the arc instability when modifying the direction of welding (pulling and pushing) and that the polarity of HW was responsible for attracting or repelling the arc and, along with the feed rate, it can change cord geometry at a depth of penetration by 45% and dilution up to 25% compared to GMAW when the feed rate was 100%.