Viscous characteristics and modelling of CaO–Al 2 O 3 -based mould flux with B 2 O 3 as a substitute for CaF 2

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.