Effect of the welding angle on the porosity of underwater wet welds performed in overhead position at different simulated depths

This research work reports the porosity evolution during welding in the overhead position as a function of depth and working angle between electrode and plate in the underwater wet welding (UWW) process. For this purpose, different welds were simulated inside a hyperbaric chamber at depths of 10 and 50 m using three different plate angles (10, 30 and 70 degrees) respect with the horizontal and three different weld working angles (40, 50 and 60 degrees). Varnished E6013 electrodes were used and a buoyancy-gravity running mechanized device was designed and employed for performing the welds in the overhead position. The results were discussed in terms of the physical mechanisms related to the formation of pores in the weld zone. Thus, it was revealed that the better working angle is 40 degrees with plate angle set at 10 degrees for the reason that the weld beads performed at the greatest test depth (50 m) exhibited lower levels of surface porosity (< 5%). Through metallographic analysis, it was also found that the volume fraction of pores is strongly dependent on the welding depth, which increases with the greater plate angle in both 10 and 50 m depth conditions. Accordingly, measured average porosity in the weld zone related to these welding depth conditions was 0.34 and 2.8 %, respectively.