Metal Flow Analysis in a Complex Die
A.J. den Bakker, Nedal Aluminum, Utrecht, The Netherlands
R.J. Werkhoven, TNO, Eindhoven, The Netherlands
Track: EXTRUSION/DIE THEORETICAL - Weld and Finite-Element Method
ABSTRACT—Accurate predictive control of the desired shape in extrusion can lead to
several benefits, such as a reduction of the steps in the iterative process of die trial and
correction, and enhanced dimensional accuracy. As the profile shape and dimensions depend
heavily on the flow characteristics of the extrusion tooling, the influence of the internal die
geometry on metal flow was investigated by means of finite element simulations and full
scale extrusion tests. The studied shape consisted of an asymmetrical double hollow. Three
tooling configurations were examined, together with variations in extrusion speed and billet
temperature. Composite two-part billets were extruded, consisting of AA6xxx and AA7xxx
aluminum alloys. Analysis of the flow patterns was performed by sectioning the extruded
shape at selected intervals around the transition area resulting from the composite billets and
etching the cross sections, leading to a complete reconstruction of the flow pattern.
Additionally, this method provides the opportunity to study features associated with the
charge weld evolution, as the flow pattern also represents a billet-to-billet transition. Flow
simulations were performed using a commercial FE-code for plastics extrusion, specifically
adapted for aluminum extrusion, assuming a rigid die configuration, and results are compared
with the physical test results.
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