Hot backward extrusion comparative analyses by a combined finite element method

Deformation and temperature of hot backward extrusion are complex owing to interaction between deformation and temperature. In this paper, two- and one-way axisymmetric hot backward extrusion problems are analyzed by a combined finite element method, which consists of the volumetrically elastic and deviatorically rigid–plastic finite element method and the heat transfer finite element method. The volumetrically elastic and deviatorically rigid–plastic finite element method is different from the conventional rigid–plastic finite element methods, and has some merits in comparison with the conventional methods. Because contact surfaces between workpiece and tools of the one-way extrusion are different from those of the two-way one, the deformation and temperature of the one-way extrusion are different from those of the two-way one. Contours of effective strain rate, effective strain, temperature, effective stress and hydrostatic stress, as well as plots at different reductions for the two extrusions are obtained successfully. Differences of calculated results for the two extrusions can be clearly seen through comparative analyses. e the bulk modulus is introduced into the volumetrically elastic and deviatorically rigid–plastic finite element method, influence of temperature on hydrostatic stress can be considered in this paper.