Viscous characteristics and modelling of CaO–Al2O3-based mould flux with B2O3 as a substitute for CaF2

Abstract

ABSTRACT Following a series of laboratory studies on the development of fluoride-free or low-fluoride CaO–Al2O3-based mould flux for continuous casting of high-aluminium steel, the viscosity properties of CaO–Al2O3-based mould flux with B2O3 as a substitute for CaF2 were investigated using the rotating cylinder method. It was found that B2O3 behaved in a similar manner to CaF2 in changing the viscosity of the flux system. From calculations of the viscous activation energies, it was found that similar changes in the concentrations of CaF2 and B2O3 resulted in almost the same changes in activation energy. A viscosity prediction model was developed using the optical basicity concept as an indicator of melt behaviour. Predicted viscosity values showed good agreement with measurements reported in the literature.