Axisymmetric extrusion forging: Effects of material property and product geometry

Experiments have been carried out on lead and copper cylindrical billets using simple extrusion forging dies under quasi-static and dynamic conditions to produce boss and flange type components. It was observed that during the initial stages of the deformation process, the flow pattern of the metal is significantly different to what is normally assumed in theoretically analysing the process. The profile of the flange becomes very much tapered and the height of the boss obtainable is dependent on the boss to billet dimensional ratio.

A theoretical analysis is presented based on rigid-plastic property of the billet material which enabled prediction of the tapered deformation profile of the flange under frictionless conditions. The agreement between the theoretically predicted deformation modes and those observed experimentally is found to be very close.