Effect of Mg–Re complex treatment on eutectic carbides in bearing steel

Effect of an Mg–Re complex treatment on eutectic carbides in bearing steel has been studied. Results show that the number, and the average maximum size of carbides tend to decrease and then increase with the increase in Mg content. When the Mg content is low, the addition of Re is not conducive to the refinement of carbides; When the Mg content is high, the number and size of carbides decreases with the increase of Re. The main reason for the refinement of carbides by Mg is that the diffusion of Mg hinders the diffusion of C and Cr, so that the formation and growth of carbides are inhibited. A large number of MgS-MnS can induce the precipitation of carbides, which also leads to the dispersion of carbides. While the Re‑Mg complex treatment, the inclusions containing Re and segregation of Mg is the main reason for the refinement of carbides.