A backward extrusion of non-circular sections from round billet was analysed by the upper bound method. To obtain the solution for the flow pattern and extrusion pressure, a three dimensional kinematically admissible velocity field derived for forward...
A backward extrusion of non-circular sections from round billet was analysed by the upper bound method. To obtain the solution for the flow pattern and extrusion pressure, a three dimensional kinematically admissible velocity field derived for forward extrusion of general shapes was applied using velocity transformation. The objective parameters associated with the velocity field and deforming zone shapes were calculated through minimization of the extrusion power. As an optimization technique the flexible tolerance method was used.