Separation mechanism of inclusion from molten steel during RH treatment

Abstract

Behavior of Al2O3 inclusion particles in molten steel was researched after deoxidation in RH degasser and ladle refining furnace (NK-AP). Diameter distribution of inclusion particles was measured by photo scattering method. In result, it was observed that inclusion particles were almost Al2O3 spheres and logarithm of number of inclusion particles were directly proportional to diameter of inclusion particles in Al-killed molten steel. It was observed that removal rate of bigger inclusion particles were faster than that of smaller inclusion particles, and particles under 3μm were hard to be removed. Because it was cleared that inclusion particles weren't removed by floating of mono-particles, model considered turbulent coagulation of inclusion particles in stirring molten steel was constructed by Saffman-Turner model and mass balance of inclusion particles. In result, behavior of inclusion particles in molten steel was explained in both of RH degasser and NK-AP by this model.