The manufacturing process of double alloy hardened screw is as follows: the forged medium carbon alloy steel is quenched, tempered and heat treated at high temperature (or low temperature) and machined into screw, and the nickel base wear-resistant alloy is overlaid by plasma (flame). The metallographic structure is composed of tempered sorbite or martensite and carbide. The screw has good strength and high surface hardness of the screw edge, which is suitable for general wear-resistant screw. It is widely used in injection molding of PC, PE, PA, PS, PMMA, ABS, PVC, PSU, POM plastics, etc.