Study of dual pulse gas metal arc welding process characteristics on IS 2062 steel

Abstract

Dual pulse gas metal arc welding (DP-GMAW) is a superior welding process where the weld quality and strength of weldment is highly dependent on weld input parameters. It is important to understand the effect of different input parameters on the effectiveness of welding, especially for commonly used mild steels such as IS 2062. This work attempts to study the effect of current, voltage, wire feed rate (WFR) and standoff distance (SOD) during DP-GMAW of IS 2062 steels. The interaction of WFR and varying welding current, voltage, weld pool geometry and %dilution was investigated through bead-on-plate weld method. A plate was welded using DP-GMAW process with a WFR of 8 m/min, SOD of 15 mm and a travel speed of 25 cm/min. The side and face bend tests of DP-GMA welded plates revealed that the weld quality was good without any crack. The hardness of the weld zone was significantly higher than the base metal. The strength, elongation and Charpy V-notch impact energy of the weldment was comparable to that of the base metal. A simultaneous increase of microhardness and toughness of the welded sample was observed. Metallographic tests revealed that this phenomenon was due to the presence of fine grain structure containing acicular ferrite and Widmanstatten ferrite in the weld metal which was generated due to the superimposition of current pulsation over thermal pulsation during DP-GMAW process.