A structure-oriented elucidation for viscous flow of SiO2-MnO-Al2O3 fused submerged arc welding fluxes

Understanding the physiochemical properties of flux is critical to addressing the challenges towards developing high heat input welding flux. In this study, the viscous behavior and structure of ternary SiO2-MnO-Al2O3 submerged arc welding fluxes were investigated using the rotating cylinder method for viscosity measurement, Raman spectroscopy and X-ray photoelectron spectroscopy for structure analysis. The results showed that the viscosity increased with the substitution of MnO with Al2O3, which is correlated to the enhancement in the degree of polymerization of the flux as the activation energy increased from 71.36 to 119.71 kJ/mol with increasing Al2O3 content from 0 to 20 wt.pct. The enhanced (Q(2)+Q(3)+Al-O-0)/(Q(0)+Q(1)+Al-O+AlO6) ratio indicated the continuous polymerization of the flux structure, which was further confirmed by the distribution characteristics of various oxygen species and thermodynamic analysis.

Automated summary

The viscous behavior and structure of ternary SiO2-MnO-Al2O3 submerged arc welding fluxes were investigated in this study. The results showed that the viscosity increased with the substitution of MnO with Al2O3, indicating enhanced polymerization of the flux. The (Q(2)+Q(3)+Al-O-0)/(Q(0)+Q(1)+Al-O+AlO6) ratio confirmed the continuous polymerization of the flux structure.