Pinpointing Element Transfer Locations during Submerged Arc Welding

Due to the shielding effect of fluxes, investigations into element transfer during submerged arc welding are often restricted by and/or limited to compositional analysis of the weld metal (WM). Therefore, meaningful discussions about specific locations where responsible reactions occur, such as the arc-containing droplet zone and arc-free slag-metal zone, are often nebulous. To counter such challenges, designed droplet collection trials were conducted over a water-cooling system. By examining the contribution of droplets to element transfer in the WM, the locations and possible pathways facilitating salient element transfer behaviors were elucidated. The results indicated that the transfer levels of Si, Mn, and Ti from the flux into the droplet were, on average, 0.016 wt-%, 0.079 wt-%, and 0.004 wt-% higher, respectively, than levels into the WM, suggesting that element transfer occurred primarily in the droplet zone. The transfer level of O from fluxes into droplets was, on average, 0.022 wt-% lower than that to the WM, indicating that beyond the droplet zone, alternative sources contributed to the increase in O content within the WM. The findings provide a theoretical foundation for precisely manipulating WM compositions and potentially optimizing the entire welding process to a new level.