Turning processing is the use of the product in the lathe lathe into a part, to change the shape and size of blank by linear movement or curve movement of the workpiece rotation and tool, processing it into line with the requirements of the drawings. Turning the workpiece in a lathe using method of tool rotation relative to the machining of a workpiece. Turning to the main cutting tool provided by the workpiece instead. Turning machining method is the most basic and most common, occupies a very important position in the production. Lathe for processing rotary surface, most has the rotary surface of workpiece can be machined by turning method, such as the external cylindrical surface, conical surface, inner and outer face, groove, screw and rotary forming surface, the tool is mainly used tools. Turning accuracy is generally IT11-IT7, some can reach IT6, surface roughness Ra can reach 12.5-08um. And by turning the parts we called turning parts, turning parts of many types, in order to maintain thermal stability of hard turning parts of the famous.