中文摘要：

通过氧氮分析、ICP-AES、SEM和EDS，试验研究4种成分不同的碱性中间包覆盖剂对钢水洁净度的影响，并从热力学角度分析了覆盖剂对钢液造成氧化的原因。结果表明，在1550℃下，提高中间包覆盖剂碱度以及降低其中MgO、Al2O3含量均有利于降低钢中的总氧含量，覆盖剂碱度最高时，T[O]含量最低，为12．8×10-6；在一定程度上增加中间包覆盖剂的碱度有利于钢中夹杂物数量的减少及尺寸的减小，但碱度过大反而不利于细小夹杂物的形成；此外，碱度更高的覆盖剂中SiO2活度相对较低，向钢液中传氧量较少，因而对钢液二次氧化的程度小，更利于洁净钢的生产。

英文摘要：

By means of oxygen and nitrogen analyzer, ICP-AES, SEM and EDS, the effect of four basic tundish slags with different compositions on the cleanliness of molten steel was investigated experimentally. The reoxidation behaviors of molten steel caused by tundish slag contamination were ana- lyzed in view of thermodynamics. The results show that high slag basicity and low MgO and Al2O3 contents are benificial to the reduction of total oxygen content in molten steel at 1550℃. Among them, test with highest slag basicity exhibits lowest total oxygen content, which is 12.8× 10-6. To some extent, the increase of slag basicity is also favorable to the decrease of the size and the number of inclusions, but excessively high basicity may have a negative effect on the formation of tiny inclusions. In addition, slags with higher basicity can provide less oxygen to the liquid steel due to its low- er SiO2 activity, thus reducing the degree of secondary oxidation of the molten steel, which is benefi- cial to the production of clean steel.