Effect of alternating shielding gases in gas metal arc welding of SA515 Gr 70 carbon steel

Abstract The influence of alternating shielding gas on fusion characteristics and weld metal characteristics was examined using a solid wire electrode on SA515Gr 70 carbon steel (ER70S). To improve the efficiency of the traditional GMAW process, two shielding gases of Argon and CO 2 were supplied independently to the GMAW torch using a gas alternator unit with a predetermined frequency to the weld area. The weld quality was found to be improved by the periodic variation of the arc. The weld pool dynamics got refined by the enhanced thermo physical properties driven by the alternating shielding gases. Based on the results of the bead on plate welding trial, optimal welding conditions were chosen to construct a single V groove butt-joint weld to characterize its strength and toughness. The alternating shielding gases delivered excellent outcomes in terms of weld bead geometry and mechanical properties in this investigation.