ABSTRACT Ca treatment is generally used in the production of Al-deoxidised steel to prevent nozzle blockage by modifying high melting point inclusions such as MgO·Al2O3 (Melting point: 2408 K). However, the successful application of Ca treatment can be quite difficult due to the requirements for stringent control of the amount of calcium that is added. In the present paper, a novel and effective method of inclusion modification by Na2CO3 treatment is developed and the evolution process of inclusions in Al-deoxidised steel with Na2CO3 treated is studied, which is in good agreement with FactSage calculation results. In addition, the relevant refractory/steel/inclusion interaction mechanisms are also discussed. The experimental results show that MgO–Al2O3 inclusions can be transformed into Na2O–MgO–Al2O3–SiO2 inclusions with low-melting points by Na2CO3 treatment. After Na2CO3 addition, both the dissolved [Na] and [Si] start to reduce MgO and Al2O3 in the generated MgO–Al2O3 inclusions from outside to inside, accompanied with the reduction of MgO–Al2O3 reaction layer at the steel-refractory interface by [Na] and [Si] in the steel.

中文翻译：

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用 Na2CO3 处理的铝脱氧气门弹簧钢中的耐火材料/钢/夹杂物相互作用

摘要 Ca 处理通常用于铝脱氧钢的生产，通过改变高熔点夹杂物如 MgO·Al2O3（熔点：2408 K）来防止喷嘴堵塞。然而，由于需要严格控制添加的钙量，成功应用 Ca 处理可能相当困难。本文开发了一种新型有效的Na2CO3处理夹杂物改性方法，研究了Na2CO3处理的铝脱氧钢中夹杂物的演变过程，与FactSage计算结果吻合较好。此外，还讨论了相关的耐火材料/钢/夹杂物相互作用机制。实验结果表明，通过Na2CO3处理可以将MgO-Al2O3夹杂物转化为低熔点的Na2O-MgO-Al2O3-SiO2夹杂物。添加 Na2CO3 后，溶解的 [Na] 和 [Si] 开始从外到内还原生成的 MgO-Al2O3 夹杂物中的 MgO 和 Al2O3，伴随着钢-耐火材料界面处的 MgO-Al2O3 反应层的还原[钢中的 Na] 和 [Si]。