铈在253MA耐热钢中赋存状态的热力学分析

基于多相多组元反应平衡原理及凝固过程固液相界面的溶质再分配理论,建立了稀土耐热钢凝固过程中夹杂物析出与溶质元素微观偏析的耦合热力学模型,并通过工业试验验证了该模型的准确性。利用该模型系统研究了在不同铈含量、氧含量、硫含量条件下253MA耐热钢中固溶的铈含量。在本模型计算条件下,为保证耐热钢中较高的固溶铈含量,铈添加量(质量分数)须在0.025%以上;钢中的氧硫的质量分数应满足%O]+%S]0.009(%O]0.0046)及2%O]+%S]0.014(%O]0.0046)。

Thermodynamic Study on the Occurrence of Cerium in 253MA Heat-Resistant Steel

A coupled thermodynamic model of inclusions precipitation and solute elements microsegregation during solidification of 253 MA steel was established basing on the reaction equilibrium principle of multiphase and polycomponent and the redistribution theory of solute elements in the interface of liquid and solid during solidification.Then the accuracy of this model was validated through the commercial test Using this model,the dissolved cerium content in 253 MA steel with different conditions,such as cerium addition,oxygen content and sulfur content,was calculated.Under the rated condition of the model,some results were obtained as follows.In order to keep high dissolved cerium content in 253 MA steel,the cerium additionCmass fraction） must be higher than 0.025%and%O]＋%S]〈0.009（%O]〈0.0046）,2%O]＋%S]〈0.014（%O]〉0.0046）.