Properties of F-free glass system as a mold flux: viscosity, thermal conductivity and crystallization behavior

While the fluorine included in mold flux is an additive widely applied to reduce viscosity and solidification temperature, it causes the corrosion of casting machine and the environmental pollution. In order to resolve these problems, F-free mold flux was examined in the glass system of CaO–SiO2–Al2O3–Na2O–B2O3, and their properties such as viscosity, thermal conductivity and crystallization behavior were observed and compared with commercial mold flux used in high speed process of the continuous casting of steel. As a result, it was confirmed that S4 (CaO/SiO2=1.7) was the optimum composition which had similar physical properties and crystallization behavior to the commercial mold fluxes.