稀土铈对钢中溶质碳偏析影响的热力学研究

A Thermodynamic Study of Cerium Effect on the Carbon Segregation in Steel

摘要:

以Fe-C-Ce合金为对象,建立多元合金溶质分配系数热力学计算模型,并利用FactSage Equilib模块计算不同铈含量下凝固体系中溶质碳的平衡分配系数,以此研究稀土铈对钢中溶质碳偏析的影响。结果表明：稀土铈对体系的凝固相转变影响较大。铈的添加可促使奥氏体的转变,使L+γ固-液共存区扩大,从而使碳的平均平衡分配系数增大,起到减小钢中碳偏析的作用。改善钢中碳偏析的最适宜铈添加量与碳含量有关。Fe-0.1%C-x%Ce体系最适宜的稀土铈添加量为0.047%~0.057%。Fe-0.25%C-x%Ce体系最适宜的稀土铈添加量为0.03%~0.04%。

Abstract:

In order to investigate the effect of cerium on the carbon segregation in steel, a thermodynamic calculation mold of equilibrium partition coefficient in multi-component alloy is established. The equilibrium partition coefficient of C in Fe-C-Ce system with different cerium content is calculated with Equilib moudle of FactSage. Results show that the effect of cerium on phase transformation is remarkable during solidification. The addition of cerium facilitates austenite transformation and enlarges the L-γ coexist zone. Cerium increases the average equilibrium partition coefficient which means it can mitigate the segregation of C in steel. The optimum addition content of cerium to improve the segregation of C in steel are associated with carbon content. For Fe-0.1%C-x%Ce system, the optimum addition content of cerium ranges from 0.047% to 0.057%. And for Fe-0.25%C-x%Ce system, the optimum addition content of cerium ranges from 0.03% to 0.04%.