PMO-EMS组合调控提高铸坯均质化应用实践

脉冲磁致振荡(PMO)凝固均质化技术是通过促进形核并形成“结晶雨”细化凝固组织、提高铸坯均质化的一项原创技术。生产实践表明,该技术对提高连铸坯等轴晶率、降低偏析具有显著作用。将PMO与电磁搅拌(EMS)进行优化组合,利用EMS的搅拌作用,将PMO形成的“结晶雨”均匀分布于铸坯心部,消除等轴晶区偏心问题,从而大幅度提高铸坯组织对称性和均质化效果稳定性。结果表明,应用PMO-EMS组合调控技术可显著提高铸坯均质化水平,以轴承钢GCr15和齿轮钢20CrMnTi为例,等轴晶区对称性明显增加,偏析指数则可以分别控制在1.04和1.05以内。

Application of PMO-EMS combined control to improve the homogenization of casting billet

Pulsed magneto-oscillation(PMO) is an original homogenizing technology to refine the solidification structure and improve the homogenization of billets by promoting nucleation and forming grain rain. The production and application practice show that this technology has a significant effect on improving equiaxed grain ratio and reducing macrosegregation index of billets. In this study, an optimal combination of PMO and EMS was used to promote nucleation and form the “grain rain” effect and the stirring effect of EMS. The “grain rain” formed by PMO was dispersed evenly in the center of the billet, eliminating the eccentricity of equiaxed grain zone, thus greatly improving and stabilizingthe symmetry of solidification structureand homogenization effect of a billet and its stability. The results show that the application of PMO-EMS combined processcan significantly improve the homogenization of billets, and the central carbon of bearing steel GCr15 and gear steel 20CrMnTi can be controlled within 1.04 and 1.05, respectively.