Cold forging, also known as cold forming, is a general term for the processing method that applies a compressive force to a material at room temperature to obtain the desired deformation. Cold forging process does not need to carry out fine cutting processing and obtain the precision and surface accuracy of the product, saving energy, but also can improve the performance of the material, and has gained wide use. In addition to bolts and nuts, cold forging is also an indispensable production method in the mass production of bearings, household appliances and automotive parts. In recent years, cold forging has begun to be applied to small batches of high-strength materials, large parts processing, and gradually into the hot forging, cutting and casting and other processing fields.

Cold extrusion processing, using a convex die (punch) on the metal material placed in the concave die to apply strong pressure, so that the material to the concave die opening or the gap between the concave and convex die out of the shape. The cold extrusion process is divided into three types: forward extrusion, reverse extrusion and compound extrusion. Cold extrusion processing occasions, the need for large-capacity presses, and due to high stress, die life is short, but with the development of convenient and effective lubricants, its scope of application continues to increase. With the development of cold extrusion technology of steel, its processing degree than the original compression processing increased a lot, many of the original can only be shaped by hot forging products, now also can be shaped by cold extrusion.