Cold forging of flange is a process of forging at low temperature, and the size of flange changes little. When forged below 700 C, less oxide scales are formed and no decarbonization occurs on the surface. Therefore, as long as the deformation energy is within the range of forming energy, cold forging can easily obtain good dimensional accuracy and surface finish. As long as temperature and lubrication cooling are well controlled, warm forging below 700 C can also achieve good accuracy. Cold die forging, cold extrusion, cold upsetting and other plastic processing. Cold forging is a forming process below the recrystallization temperature of the material and a forging process below the recovery temperature. In production, it is customary to call forging without heating blank as cold forging. Cold forging materials are mostly aluminium and some alloys, copper and some alloys, low carbon steel, medium carbon steel and low alloy structural steel with small deformation resistance and good plasticity at room temperature. Cold forgings have good surface quality and high dimensional accuracy, which can replace some cutting processes. Cold forging can strengthen metal and improve the strength of flange.
The development of cold forging technology is mainly to develop high value-added products and reduce production costs. At the same time, it is constantly infiltrating into or replacing cutting, powder metallurgy, casting, hot forging, sheet metal forming process and other fields. It can also be combined with these processes to form a composite process.