Probing Viscosity and Structural Variations in CaF2–SiO2–MnO Welding Fluxes

Recent demand on welding fluxes for high-strength low-alloy steel grades has necessitated the development of CaF2-free towards high heat input applications. To meet such requirements, a flux design strategy been postulated by varying MnO/(CaF2 + MnO) mass ratio in CaF2–SiO2–MnO system. The effect MnO substitution CaF2 viscosity and structure investigated, quantitative relationship between structural units put forward. In addition, it suggested that degree polymerization (DOP) silicate network is reduced with increasing ratio, indicating plays role network-breaker. spectra F1s 19F prove F− predominantly bonds Ca2+ rather than Si4+, revealing acts as diluent does not effectively depolymerize network. Linear correlations can be obtained logarithm average non-bridging oxygen per silicon atom (NBO/Si), which potentially used DOP index to quantify impact flux.