Development of a Generalized Analytical Method for Three Dimensional Tube Extrusion of an Elliptic Section through a Continuous Die

摘要

In the present paper the axial velocity component on the intermediate cross-section in the plastically deformed region is expressed as a general function of the coordinates and this allows the description of complete three-dimensional distortion of flow rendering and also more realistic flow patterns. From the derived kinematically admissible velocity field, the corresponding upper-bound extrusion pressure is then obtained by optimizing the pressure with respect to the given parameters. The grid distortion is computed by tracing the metal flow along the streamlines. The effective strains are computed in order to study the work hardening pattern of the extruded products. In this research ANSYS (11) software was used in building, loading, and solving the extrusion process. The model generation depends on the billet, AL 2024 fully annealed has been chosen as the working material. In the computation the product shape was ellipse. The effects of area reduction, die length, product shape complexity and frictional condition on the extrusion pressure, the metal flow and the distribution of the final effective strains have been studied extensively. The finite element method simulation, using ANSYS (11) Software, and theoretical predictions both in extrusion load and metal flow are in a good agreement with the experimental results.