Effect of TiO2 enriched fluxes on the bead geometry, grain size and hardness in submerged arc welds

This work is mainly concerned about the influence of titanium dioxide powder addition into flux on the bead geometry, grain size, and hardness in submerged arc weld of low alloy steel plates. Titanium dioxide powders were mixed with the commercial fluxes in a different proportion of 2.5, 5, 7.5, 10 and 12.5%. The welding process parameters were kept constant for different welding conditions. Bead geometry parameters show a significant improvement due to the titanium dioxide addition. 5% of titanium dioxide enrichment was showing the best result for the bead geometry parameters. Nucleation of the acicular ferrite and grain refinement of weld metal (WM) microstructure has been observed with the enrichment of titanium. Average grain size of ferrite and pearlite decreases with the increase of titanium content. Phase analysis of WMs shows that the ferrite% increased and pearlite% decreased with respect to titanium content. But, the increase of titanium content was not showing any clear trend on the hardness profile of weldments.