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)。 Based on the principle of multi-phase multi-component reaction equilibrium and solute redistribution theory of solid-liquid interface during solidification process, a coupled thermodynamic model of inclusion precipitation and solute micro segregation during solidification was established. The industrial thermodynamic model was established The accuracy of the model. The model system was used to study the content of cerium dissolved in 253MA heat-resistant steel under different contents of cerium, oxygen and sulfur. Under the condition of this model calculation, in order to ensure the high solid solution cerium content in the heat-resistant steel, the content of cerium (mass fraction) should be over 0.025%; the mass fraction of oxy-sulfur in the steel should satisfy [% O] + [ % S] <0.009 ([% O] <0.0046) and 2 [% O] + [% S] <0.014 ([% O]> 0.0046).