“…German scholars like Pehle, Thieven, etc., adopted the three-dimensional FEM to simulate the production process of the stretch reducing in the Mannesmann plant using the commercial software, and studied the three-dimensional deformation, contact problems, the impact of the roller profile and the tension on the stretch reducing process, especially the variation of the tube wall thickness and so on [5]. The specialists of Timken company in USA, such as Gulyayev, Sawamiphakdi, etc., studied the problems of the FEA model to simulate the stretch reduc- ing process, the contact problems, the variation of the tube wall thickness and so on [6,7]. Chinese experts, Du Fengshan, etc., simulated the production process of the stretch reducing of the Baosteel company using self-programming three-dimensional elastic-plasticity FEM software.…”