Si-Ca-Ba复合脱氧剂成分设计与脱氧能力的热力学研究

Thermodynamic study on component design and deoxidization ability of Si-Ca-Ba complex deoxidizer

Si-Ca-Ba复合脱氧剂常用于对Al2O3类夹杂物敏感、不宜用Al脱氧的钢种。针对该类脱氧剂实际使用过程成分设计与脱氧效果稳定性问题,基于经典热力学,运用Factsage7.0软件研究分析了不同配比下Si—Ca-Ba复合脱氧剂的脱氧效果与组元作用规律。考虑实际含BaO精炼渣工况,比较了渣的二元碱度对辅助脱氧效果的影响。研究表明,无渣工况下,随Si-Ca—Ba合金中Si和Ba配比的增加,其复合脱氧效果变差;随Ca配比的增加,脱氧效果明显增强。有渣工况下,随着精炼渣碱度的增加,该脱氧剂脱氧效果增强;精炼渣碱度在2.5时,根据各组元比例不同,相同脱氧量下,每吨钢液合金用量介于0.6~0.9kg;当Si-Ca-Ba三组元比例各自在1/3~2/3范围变化时,提高Si配比脱氧效果增强,而提高Ca或Ba配比脱氧效果变化不大。精炼渣碱度为2.5时,Si:Ca:Ba质量比为4:1:1时脱氧效果最佳,Fe-O溶液中溶解[O]含量最低。

Si-Ca-Ba complex deoxidizer has been widely applied in such steel grades which are sensitive to Al2O3 type inclusions. In view of the composition design and the stability problem of deoxidization effect during the actual use for this kind of deoxidizer, its deoxidization ability and the component action under different elemental ratios were studied, based on the classical thermodynamics and Factsage 7.0 software. Additionally, the effect of the binary basicity of refining slag containing BaO on deoxidation was discussed. The results show that in the case of without slag, the deoxidation effect of complex deoxidizer becomes weak with the increase in the contents of Si and Ba in alloy and with the decrease of Ca content. When considering the refining slag, the deoxidation ability of deoxidizer increases with the slag basicity. As the basicity of refining slag is at 2.5, the consumption of alloy under the same deoxidization amount is between 0.6 and 0.9 kg/t steel;when the proportion of the three elements in Si-Ca-Ba alloy varies in the range of 1/3-2/3, the increase of Si content can enhance the deoxidation effect, whereas Ca and Ba affect minor. At the slag basicity of 2.5, the 4∶1∶1 in mass proportion of Si-Ca-Ba alloy can achieve the lowest content of dissolved oxygen.