Research on 20G Steel Oxide Inclusion Control and Calcium Treatment via Thermodynamics Method

During the early stage of producing grade 20G steel,crack defects and macro-structure defects were frequently observed which were expected to decrease rolling qualified rate and yield.In order to solve the crack problem and to improve steel product quality,a thermodynamics method was used to determinate the relationship between equilibrium composition of possible first deoxidizing product and liquid steel compostion in the processes of first deoxidation where Al₂O₃ and SiO₂ dominate.Then activity changes of calcium,aluminum,oxygenium and sulphur had been calculated inclusion modification path had been determinated during calcium treatment which can provides theoretical basis for inclusion formation,modification and removal.