Aluminium powder forging process using a rotating platen

A torsional upset forging process is analysed on the basis of plasticity theory for powder metal forging. Torsional upset forging is a process to be performed by rotating a lower die with a punch travelling along the longitudinal direction of a work-piece. In this study, an upper bound analysis considering bulging effect, finite element method simulation (DEFORM3D), and experimental research have been performed for the process. A simple kinematically admissible velocity field for a three dimensional deformation is presented for the torsional upset forging of a cylindrical billet. Distributions of stress, strain, and forging load in the process have been obtained, and compared with those in conventional upset forging. In the process, an increase in a friction factor and rotation speed results in a decrease in magnitude of upset force, dead metal zone, and non-homogeneous deformation. This process can reduce forming load, which leads to improvement of die life, and also reduce bulging effect. In addition, the initial sintered-structure and density distribution is improved by the process and surface defect due to high deformation is decreased.