The effect of cerium on inclusions in an ultra-low-carbon Al-killed steel was studied at 1873 K (1600 °C) using laboratory experiments. The content of cerium in the steel varied from 0 to 0.028 wt pct. The contents of the total oxygen (T.O), total nitrogen (T.N), total sulfur (T.S), total cerium (T.Ce) and dissolved aluminum ([Al]) in the steel samples 1, 5, 10 and 30 minutes after adding cerium were measured, and inclusions were characterized using an automatic scanning electron microscope. It was found that a cerium-concentrated zone formed after the cerium alloy was added to the molten steel. Many inclusions were generated in the cerium-concentrated zone and then disappeared with the decrease of the cerium content. The variation of the inclusion composition was Al 2 O 3 → CeAlO 3 → Ce 2 O 2 S → Ce 2 O 2 S + CeS with the increasing cerium content in the steel, which agreed well with the thermodynamic analysis. The value of T.Ce/T.O was able to evaluate and predict the type of inclusions. A prediction model of the composition of inclusions was established based on thermodynamic calculation and mass balance and was validated by experimental data. When the value of T.Ce/(T.S + T.O) was ≥ 4.4, the average composition of inclusions changed little since most inclusions were fully modified.

中文翻译：

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铈含量对超低碳铝镇静钢中夹杂物的影响

使用实验室实验在 1873 K (1600 °C) 下研究了铈对超低碳铝镇静钢中夹杂物的影响。钢中铈的含量从 0 到 0.028 wt pct。1、5、10、30分钟后钢样中总氧（TO）、总氮（TN）、总硫（TS）、总铈（T.Ce）和溶解铝（[Al]）的含量测量添加铈，并使用自动扫描电子显微镜表征夹杂物。发现在将铈合金添加到钢水中后形成了铈浓缩区。在铈的富集区产生许多夹杂物，然后随着铈含量的减少而消失。随着钢中铈含量的增加，夹杂物成分的变化为Al 2 O 3 → CeAlO 3 → Ce 2 O 2 S → Ce 2 O 2 S + CeS，与热力学分析结果吻合较好。T.Ce/TO 的值能够评估和预测夹杂物的类型。建立了基于热力学计算和质量平衡的夹杂物成分预测模型，并通过实验数据进行了验证。当T.Ce/(TS+TO)≥4.4时，夹杂物平均成分变化不大，大部分夹杂物完全变质。建立了基于热力学计算和质量平衡的夹杂物成分预测模型，并通过实验数据进行了验证。当T.Ce/(TS+TO)≥4.4时，夹杂物平均成分变化不大，大部分夹杂物完全变质。建立了基于热力学计算和质量平衡的夹杂物成分预测模型，并通过实验数据进行了验证。当T.Ce/(TS+TO)≥4.4时，夹杂物平均成分变化不大，大部分夹杂物完全变质。