The influence of GMAW correction parameters on stabilizing the deposition characteristics for wire arc additive manufacturing

Abstract

The present work investigates the effects of correction parameters, viz. Arc Length Correction (ALC), Dynamic Correction (DC), and Pulse Correction (PC) on the deposition of ER70S-6 filler wire on a mild steel plate using two modes of the GMAW process, i.e., Cold Metal Transfer (CMT) and Pulsed mode. Controlling the heat input to improve the bead quality with varying correction parameters is investigated. The changes in welding current (I) and voltage (V) waveforms are explored in synchronization with high-speed arc imaging and the consequent effect on heat input, frequency, and stability of the I-V characteristics. Considering the above changes, an analysis of the influence of correction parameters on bead width, height, penetration, and microhardness is done. The variability in the above-stated weld bead properties along the length of deposition is investigated to establish a set of correction parameters most likely to provide a stable and consistent deposition. Heat input increases with increasing ALC and decreases with increasing DC and PC for a constant wire feed rate and welding speed. Bead width and penetration increase while bead height and microhardness decrease with heat input. The deviations in bead dimensions along the length of deposition directly correlate with the deviations in instantaneous heat input. The above results render the process much-needed flexibility and consistency for advanced welding and Wire Arc Additive Manufacturing (WAAM) applications.