The shaft part is a common part in the machine. Usually, the structure of shaft parts is a rotating body, the length is generally greater than the diameter, in a variety of mechanical equipment has a wide range of uses, used to support transmission parts, transfer torque and withstand loading.
Compared with castings, metal forging can improve the structure and mechanical properties. Casting organization after forging method of thermal deformation due to metal deformation and recrystallization, make original bulky dendrite and columnar grain to grain is fine and uniform axial recrystallization organization, make the ingot in the original segregation, porosity, porosity, slag compaction and welded, such as its organization become more closely, plasticity and mechanical properties of the metal.
Forging can be divided into hot forging, warm forging and cold forging according to the forging temperature of billet during processing. The initial recrystallization temperature of steel is about 727℃, but 800℃is generally used as the dividing line, and above 800℃is hot forging. Between 300℃and 800℃is called warm forging or semi-hot forging, forging at room temperature is called cold forging.
