Physical Properties and Regulating Mechanism of Fluoride-Free and Harmless B2O3-Containing Mould Flux

The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3, was selected as flux. The physical properties of B2O3-containing mould fluxes were studied. The corresponding physical properties of 37. 91% CaO-43. 09% SiO2-5% Al2O3-5% MgO-2% Li2O-7% B2O3 mould fluxes were as follows: the melting point was 909°C, the flowing temperature was 1 160 °C, the viscosity and surface tension at 1 300 °C were 0.4 Pa · s and 0. 32 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.