Closed die drop forging, or closed die forging, is a forging way that presses heated round metal bar into the shape we need under the pressure of the dies. It will ensure the accuracy of dimensions and little machining allowance, no structure limit, high production efficiency. General steps of closed die drop forging are: mould developing-raw material cutting-heating material-forging-trimming cutting-heat treatment-shot blasting-machining-surface treatment-package. Materials that applied in drop forging process can be stainless steel, alloy steel, carbon steel, copper and other forged materials.