Phase balance in liquid steel at cerium introduction

Thermodynamic aspects of processes of steel deoxidizing with cerium-containing alloys are considered. On the basis of data on heats and temperatures of melting the types of phase diagrams of FeO-Ce 2O 3, FeO-CeO 2 and CeO 2-Ce 2O 3 systems are established in the framework of the perfect solution theory. Surface of solubility of cerium, oxygen and carbon in liquid iron is constructed. It is established that CeO 2 inclusions may appear in steel at ultralow concentrations of cerium and high content of oxygen. Nonmetallic inclusions that may form at conventional concentrations obtained on introduction of cerium in metal (200-300 g/t) are complex oxide melts or Ce 2O 3.