Thermo-viscoplastic and viscoplastic finite element analysis are made for the study of deformation and temperature distribution in axisymmetric and plane strain forging. A rigid viscoplastic material model is used so as to take the strain rate effect into account. Computer programs are developed for axisymmetric and plane strain forging.
As examples of viscoplastic analysis of hot forging processes, combined backward extrusion with rounded punches of various radii and free forging of round bars with flat and inclined platens are analyzed. Stress and strain distributions are computed for these examples. For combined backward extrusion, the effect of punch geometry on the inward flow is discussed from the comparison between the computation and the experiment carried out for pure Aluminum specimens. The computed results are in good agreement with the experimental observations. The optimal die geometry is recommended based on the computed and experimental results.
A coupled analysis of viscoplastic deformation and heat transfer is made for upsetting of a simple cylinder both for isothermal and nonisothermal conditions. The distribution of temperature and strains is found and the temperature effect due to the variation of die velocity is discussed.