Study in shaft end forming quality of closed-open cross wedge rolling shaft using a wedge block

Abstract

Because of the existence of the stub bar, the material utilization can hardly be improved when forming the shaft end by cross wedge rolling (CWR) technology. In order to solve the problem of end quality, a new method, closed-open CWR technology using a wedge block, is presented in this paper. Firstly, shaft end is formed to cone by closed rolling and then rolled by open rolling to eliminate the concave heart. The stable rolling condition of closed CWR and the corresponding design rule of the wedge block are established as well. The simulation of closed-open CWR shaft parts using the wedge block is performed by the finite element software DEFORM-3D. The strain rate and displacement field in three stages are analysed systematically, and the metal flow rule of the shaft during rolling is illuminated. The simulation result indicates that the good rolling quality in shaft end can be ensured by this method. The experiments of rolling shaft parts by a new method and single-open CWR were performed, respectively. The results demonstrate that the concave heart value of the rolled part’s end can be reduced about 78% by the new method, comparing to the single-open CWR, and are consistent with the simulation analysis. The research result provides a reliable theoretical basis for improving the shaft’s end quality of CWR.