Preface

With the rapid development of mechanical manufacturing industry, the demands for high-strength and high-precision shaft parts are increasing gradually in the fields of aeronautics and astronautics, automobile, wind power, petrochemical, national defense industry, and major equipment manufacturing. Such components as thread, hollow thread, leadscrew, spline, and screw rod are very important for power transmission and play a key role for the safety operation of equipments. Traditional machining method of shaft parts as spline and screw is mainly metal cutting, which has the characteristics such as lower efficiency, and higher material and energy wasting. Meanwhile, because the metal fibers are cut off in the machining, poor mechanical property and surface quality of the components will be resulted in, and the requirements of various industrial fields cannot be satisfied. The principle of cold rolling precision forming technology is plastic forming. It is a less and non-cutting technology, in which the metal billets are continuously rolling at room temperature to produce shaft parts with complex features. Compared with traditional metal cutting processes, the production rate of this process can be improved for about 30*40 times, the forming microstructure and comprehensive mechanical property of the components can be greatly improved, the materials can be saved for 15%*30%, and the production cost can also be decreased for about 30%. This technology has been more and more focused in the production of higher strength and precision complex components, which will have an extensive application prospect, and good social economic benefit can be obtained. Cold rolling forming of shaft parts is a continuous local deforming process, the deforming mechanism is very complex, and relatively fewer researches on the process theory and mechanical analysis of spline and thread components have been carried out. In present production, experiences of technicians and workers are mainly depended on, which has limited the popularization and application of this kind of high efficient and material saving chipless technology in conditions lacking of systematical and advanced theoretical guiding. The research team of the authors has established a cold rolling precision forming joint laboratory with the Cold Rolling Technology Research and Development Center of Qingdao Shengjian Machinery Factory, Shandong, China. The cold