Forging refers to the use of forging machinery to apply pressure to metal billet to promote plastic deformation, so as to obtain a certain mechanical properties, specific shape and size of forging, it is one of the two major components of forging (including forging and stamping). Through forging, it can eliminate defects such as metal smelting, and optimize the microstructure. At the same time, because the complete metal streamline is retained, the mechanical properties of the forging is usually better than the casting of the same material. In the relevant machinery, for the important parts with high load and strict working conditions, except for the relatively simple shape that can use the rolled plate, profile or welding parts, most of the forgings will be used.