Effects of crystallisation behaviour of mould fluxes on properties of liquid slag film

Abstract

During the continuous casting of medium carbon steel slabs, stable liquid slag film performance is necessary to ensure that the process runs smoothly. In this paper, the effects of mould flux crystallisation behaviour on the properties of leftover liquid slag films were examined. First, the compositions of the leftover liquid slags of high fluorine, CaO–SiO₂–TiO₂ and CaO–SiO₂–Na₂O based mould fluxes after a single crystalline phase was separated were calculated. Then, the viscosity, melting temperature, break temperature and degree of crystallisation of each leftover liquid flux were measured. The results revealed that the properties of leftover liquid slag films of CaO–SiO₂–TiO₂ and CaO–SiO₂–Na₂O based mould fluxes are not as stable as those of high fluorine films after crystallisation. This paper provides a new method for developing fluorine free mould fluxes and for determining the most suitable type of crystalline phase that should be utilised in the continuous casting of medium carbon steel slabs.