Abstract: In order to solve the problems such as insufficient nitrocarburizing hardness and uneven core organization of oil pump gear ring, the core organization, hardness and dispersion of matrix were optimized by improving the hardenability and grain size index of raw materials and improving the normalizing, stress relief and tempering preparation heat treatment process after forging by improving the quality control of the key process of hot processing in the manufacturing process; the nitrocarburizing is improved from water cooling to air cooling, so that the surface hardness, the depth of infiltration layer is increased, the deformation is reduced, the quality level of product heat treatment is improved, and the consistency is guaranteed.