Central Bursting and Optimal Die Profile for Axisymmetric Extrusion

Abstract

A simple criterion for predicting the initiation of central burst in extrusion is proposed. The geometric conditions to avoid central bursting are predicted by using the proposed criterion under various process conditions and material properties. The optimal die profiles which minimize the extrusion power are also obtained for various process conditions. The mixed (pressure-velocity) formulation is used along with the Householder method to solve the resulting equations. It is shown that the optimal die profiles satisfy the conditions for prevention of central burst. The predictions based on the proposed criterion are in good agreement with the experimental observations and are in conformity with the results published earlier.