Cold forging is a forming process below the recrystallizing temperature of the material, and it is forged below the recovery temperature. It is customary to call the forging of unheated blank cold forging in production. Most of the cold forging materials are aluminum and some alloys, copper and some alloys, low carbon steel, medium carbon steel and low alloy structural steel with low deformation resistance and good plasticity at room temperature. Cold forgings have good surface quality and high dimensional accuracy, and can replace some cutting. Cold forging can strengthen the metal and improve the strength of the parts.