Open-die forging of sintered cylindrical billets: an analytical approach

The open-die forging (upsetting) of sintered porous materials is used widely as one of the key metal processing operations for fabricating various engineering products, and in some cases, for predicting the mechanical properties of such materials. In the present paper, an analysis of the upsetting of axisymmetric cylindrical billets of porous materials is made on the basis of plasticity theory. A newly established yield function for porous materials - proposed by the authors - is applied to simulate the consolidation of porous billets, taking into account the current state of porosity at each stage of deformation. The proposed theoretical model, combined with the concepts of the "slab method" and assuming suitable friction conditions at the workpiece/tool interface, provides with a valuable design tool, allowing for a more precise evaluation of the process loading and the shape changes of the porous billets obtained during upsetting. (C) 1999 Elsevier Science S.A. All rights reserved.