Machining processing is the process of changing the size, shape and performance of the workpiece. Machining processing consists of cold working processing and hot working processing. In general, processing in the normal temperatures and there being not any chemical and physical change, is called cold working processing. On the contrary, processing over or below the normal temperature and there being some changes of chemical and physical, is called hot working processing. Based on the ways of processing difference, the cold working processing is divided into machining and pressure processing. The hot working processing includes heat treatment, forging, and welding.