The manufacturing process of cermet screw HVOF is: forged medium carbon alloy steel is quenched by high temperature (or low temperature) tempering heat treatment, mechanically processed into screw, plasma (flame) surfacing nickel base wear resistant alloy, metallurgical structure for tempering Sorbite or martensite plus carbide composition. The screw has good strength and high surface hardness. It is suitable for general wear-resistant screws and is widely used in injection molding of PC, PE, PA, PS, PMMA, ABS, PVC, PSU, POM plastic.