Effect of refining slag containing Ce2O3 on steel cleanliness

The effect of pre-melting refining slag containing different contents of Ce2O3 on the absorption and modification of Al2O3 inclusion in an Al-killed steel was investigated through the slag/steel reaction experiment at 1600 degrees C. It was found that the replacement of 10 wt.% Al2O3 with Ce2O3 for 50 wt.%CaO-33 wt.%Al2O3-7 wt.%MgO-10 wt.%SiO2 refining slag promoted the slag absorption ability of alumina inclusion, which made the total oxygen content determined by infrared absorption method decrease from 100 to 25 ppm in 15 min. The Mg-Al-Ce-O type inclusion was also detected in the as-solidified samples by scanning electron microscopy (SEM). Thermodynamic analysis indicated that the Ce2O3 center dot Al2O3 type inclusions would be formed with the cerium content in the range of 6.9 ppb to 3.6 ppm when the content of aluminum was 0.01 wt.%.