Abstract: Aiming at the five links of vacuum induction melting, vacuum self-consumption remelting, forging, rolling and ring rolling in the production process of M50 bearing rings, the evolution of primary carbide in the whole production process was analyzed by OM, SEM, EDS and three-dimensional X-ray 3D imaging technique. The results show that the coarse primary carbides M₂C and MC precipitate along the intergranular network after vacuum induction melting. Vacuum self-consumption remelting can reduce the precipitation of primary carbides and for different positions of the vacuum self-consumption remelting ingot, the size of primary carbides precipitated at the edge is small, and the minimum volume fraction is 2.614%. The network primary carbides are partially broken in the forging process. After rolling and ring rolling, primary carbides can be further broken and distributed along the processing streamline, but the uneven distribution of primary carbides cannot be completely changed. Thermal deformation breaks and refines the carbides while holes are also formed inside and around the primary carbides.