The Influence of Shielding Gas on GTAW Welding of Aluminium Thin Sheets

Abstract

This paper investigates the influence of helium used as shielding gas in mixture with argon in GTAW of aluminium thin sheets. Pure argon has been used in contrary to argon mixture containing 50% of helium. Different welding speeds and different currents have been varied as welding parameters during welding of EN AW 5754 H22 2 mm thick test coupons. The heat input has been calculated and compared in all welds. Weld geometry has been analysed on macro sections of produced welds, along with the bend testing according to the standard EN ISO 5173:2012. The results show that type of shielding gas interacts weld geometry and structure deformation. The argon-helium mixture had higher thermal conductivity, with the same heat input calculated resulting with different weld geometry. This research can be used for data considering on GTAW of aluminium alloy EN AW 5754 H22.