An analytical approach for radial-forward extrusion process

An analytical approach is used to obtain the extrusion pressure and the strain imposed through radial-forward extrusion. For deformation analysis, the deformation volume is divided into three different regions. By considering a cylindrical coordinates, the components of the velocity field and strain rates are obtained. The effective strain achieved in each deformation region is obtained by multiplying the effective strain rates to the deformation time determined for each region. The total strain obtained from these results is large and comparable to the strain achieved by severe plastic deformation methods. Based on the upper-bound theory, an analytical equation is derived for extrusion pressure by determining the internal power and the power dissipated on all frictional and velocity discontinuity surfaces. The validity of the theoretical results is confirmed by the experiments in term of the hardness measurements and the extrusion force.