Analysis and design of flat-die hot extrusion process 1. Three-dimensional finite element analysis

Non-steady-state-coupled three-dimensional analysis is required for investigating complex material flow in practical flat-die hot extrusion processes of aluminum alloys in various channel sections. It is important since the material flow behavior actually determines the amount of distortion of the extruded product. Thus, a non-steady thermo-rigid-viscoplastic finite element program was developed for numerical simulations of the process. Since severely deforming elements of the workpiece can easily interfere with the sharp edges of the flat-die, an automatic remeshing module based on a simple section-sweeping scheme and new contact algorithm were incorporated to allow continuous simulation without manual intervention with less volume loss and computation time. With developed finite element program, non-steady finite element analyses of extrusion processes were carried out for two types of channel-section with constant bearing length of 5 mm. From simulation results, it was found that the exit velocity of the workpiece varied depending on the cross-sectional thickness of the exit and the amount of deflection of the workpiece was not greatly affected by variations of either the workpiece temperature or punch velocity under the present simulation conditions.