The precise control of non-metallic inclusions is crucial for high-end GCr15 bearing steel. This study investigates cerium (Ce)-induced inclusion modification mechanisms. Smelting experiments with 0 to 0.017 wt% Ce additions, high-temperature in situ observations, thermodynamics, and first-principles calculations were used to evaluate inclusion evolution and aggregation behaviors. Without Ce, coarse Al2O3 and MnS phases dominate. As Ce increases to 0.017 wt%, inclusions evolve sequentially into CeAlO3, Ce2O3, and ultimately, finely dispersed Ce2O2S and CeS. Thermodynamics indicate CeAlO3 nucleates preferentially, acting as heterogeneous nucleation sites for MnS. In situ observations and interparticle force calculations reveal an aggregation tendency order of Al2O3 > CeAlO3 > Ce2O3 > Ce2O2S. Furthermore, first-principles simulations confirm that Ce2O2S possesses the lowest formation energy and optimal stability, wherein Ce effectively modifies coarse inclusions into fine, well-dispersed spherical particles. Coupled with its intrinsic deoxidizing and desulfurizing effects, Ce addition synergistically modifies coarse inclusions into fine, well-dispersed spherical particles. These findings elucidate the rare-earth modification micro-mechanisms, providing a theoretical foundation for manufacturing high-quality bearing steel.
Cheng et al. (Tue,) studied this question.