Experimental Study On The Effect Of Refractory On Oxygen Content In Molten Steel

With the development and requirements of clean steel, low carbon and ultra-low carbon steel in recent years, the study of refractory focus on the impacts of refractory on the steel quality at high temperature, including C, S, P, H, T[O] and inclusions, rather than corrosion resistance and long life in the past.Based on the phase equilibrium and thermodynamic theory, the mechanism of oxygen transferring from refractories to molten steel and its affected factors were studied in this study. Through experiments, the effect of several frequently used refractories on oxygen content of molten steel at the steelmaking temperature was also studied. And the conclusions are as follows.(1) The main cause of oxygen transferring from refractories to molten steel is the equilibrium partial pressure of O2(g) decomposed by oxide composition inside the closed pores in refractories is much higher than that the equilibrium partial pressure of O2(g) in molten steel. The direct dissolution of refractory oxide into molten steel can also lead to oxygen transferring.(2) According to the varieties of the refractory and the difference of the component proportion, the ability of oxygen transferring is different. And IOP can be used to characterize this ability.(3) The ability of oxygen transferring of refractory is also indirectly affected by the varieties of deoxidizing agents and their addition amounts which are put in molten steel.(4) The ability of oxygen transferring of refractories which had been tested in this experiment can be ranked in a descending order as MgO-Cr2O3, MgO-Al2O3, Al2O3and MgO-C refractories.(5) The experimental result shows that the deoxidizing product diffusing onto the surface of refractory increases with extending the holding time.(6) Some components of refractories are the one of source which contaminates molten steel.