稀土耐热钢凝固过程中夹杂物析出的热力学分析

摘要

Based on Gibbs free energy minimization principle, the thermodynamic software FactSage was chosen to calculate and analyze the precipitation behavior of inclusions in heat resistant steel with different cerium content and cleanliness. The results show that, SiO2 and MnS inclusions are replaced by Ce2O3, Ce2O2S when cerium is added to heat resistant steel. Under the conditions of certain cleanliness of molten steel, the content of cerium when SiO2 and MnS cannot precipitate are 0.02%and 0.03%respectively; the inclusions precipitated in heat resistant steel transform from Ce2O2S, CeN, CeS to SiO2, Ce2O3 with the content of oxygen increasing. SiO2 can precipitate in steel when the content of oxygen is greater than 0.006%. The inclusions precipitated in the heat resistant steel transform from Ce 2O2S, CeN, CeS, Ce2O3 to Ce2O2S, MnS, Ce2S3 with the content of sulfur increasing. MnS can precipitate in steel when the content of sulfur is greater than 0.005%.%基于FactSage热力学软件的最小吉布斯自由能原理，系统研究了不同铈含量及钢液洁净度条件下耐热钢凝固过程中夹杂物的析出行为。结果表明：耐热钢中添加铈后，高熔点的Ce2O2S、 Ce2O3等夹杂取代了SiO2与MnS夹杂；在一定洁净度条件下， SiO2与MnS无法析出的铈含量分别为0.02%与0.03%；随着氧含量的增加，耐热钢中的夹杂物类型由Ce2O2S、 CeN、 CeS向SiO2、 Ce2O3转变，当氧含量大于0.006%时，钢中开始析出SiO2夹杂；随着硫含量的增加，耐热钢中的夹杂物类型由Ce2O2S、 CeN、 CeS、 Ce2O3向Ce2O2S、 MnS、 Ce2S3转变，当硫含量大于0.005%时， MnS夹杂开始析出。