Microhardness and element transfer investigation of weld bead using formulated Si O 2 − CaO − Ca F 2 − BaO SMAW electrode coatings

Abstract

Shielded metal arc welding electrode coating flux influence has been studied on microhardness, microstructure, and element transfer. The mixture design approach was used to design fluxes. Multi-pass bead-on-plate experiments were done. The microhardness and weld bead chemistry were studied using regression analysis. It was observed that the nickel transfer from the electrode wire to the weld pool is positively affected by the presence of $\mathrm{CaO}$ . An increase in $\mathrm{BaO}$ leads to a loss of nickel transfer. An increase in $\mathrm{Si}{\mathrm{O}}_2$ and $\mathrm{BaO}$ has shown a positive effect on molybdenum transfer. Molybdenum transfer is decreased by the increase in $\mathrm{Ca}{\mathrm{F}}_2$ . The increase in $\mathrm{BaO}$ increases the manganese transfer, whereas the increase in $\mathrm{Si}{\mathrm{O}}_2$ reduces the manganese transfer. The increase in $\mathrm{Si}{\mathrm{O}}_2$ increases oxygen potential, which results in the loss of manganese in the weld. Microhardness increases with increasing $\mathrm{Ca}{\mathrm{F}}_2$ , whereas $\mathrm{Si}{\mathrm{O}}_2$ and $\mathrm{BaO}$ have a diminishing influence on microhardness. The microstructural and energy dispersive spectroscopy analyses of the welds have been discussed. Artificial neural network models have been developed and have been found to produce better prediction accuracy.