Abstract: The effects of MgOCr2O3， MgOAl2O3， Al2O3 and MgOC refractories on the oxygen content and inclusions of the molten steel were investigated. Based on the thermodynamic theory， the mechanism of oxygen transfer from the refractory to the molten steel was also researched. The results showed that the ability of oxygen transfer of the refractories ranks in a descending order as MgOCr2O3， MgOAl2O3， Al2O3 and MgOC refractories at 1600℃. The main reason of the oxygen transferred from the refractory to the molten steel was that the equilibrium partial pressure of O2 in closed pores of the refractory produced by the decomposition of the oxide contents was much higher than that of in the molten steel. The CO formed inside MgOC refractory decomposed at the interface and dissolved in the molten steel.

Key words: refractory, closed pores, molten steel, oxygen contents, inclusions