The invention relates to a preparation process of a TiCN multilayer
composite coating layer on a slotting cutter surface of a
steam turbine rotor; and the preparation process comprises surface pretreatment of a cutter
basal body, cleaning, cutter clamping and loading, preparation of the multilayer
composite coating layer, cooling and
discharge, and aftertreatment. The multilayer structure formed by the
coating layer preparation process uses
TiN and TiCN as alternating
coating layers to prepare 50
TiN and TiCN alternating
coating layers on the slotting cutter surface;
TiN is the backing layer; and TiCN is the outermost layer. The coating layer prepared by the method relieves the
residual stress of the coating layer and the cutter
basal body, so that the bonding force of the
basal body and the coating layer is larger, the bonding degree of the coating layer is higher, and the coating layer is not easy to be stripped off. In addition, C atoms are introduced based on TiN to cause the lattice
distortion and the
solid solution strengthening effect, so that the surface
hardness of the cutter basal body can reach HV3500, the cutter
wear resistance is improved, the cutter service life is prolonged, the
machining quality of the
steam turbine rotor is guaranteed, and the production cost is reduced.