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initiation at <strong>the</strong> pole <strong>of</strong> <strong>the</strong> corrugation in <strong>the</strong>
transition between <strong>the</strong> flange and <strong>the</strong> web for
<strong>the</strong> tested configuration (Fig. 7 c). To prevent
excessive shear, especially in <strong>the</strong> transition
area between <strong>the</strong> flange and <strong>the</strong> web, a redesign
<strong>of</strong> geometry and <strong>the</strong> rollers is necessary.
Possible applications are seen in <strong>the</strong> production
<strong>of</strong> lightweight construction pr<strong>of</strong>iles
(Fig. 8 a) with reduced web thickness. Beyond
that, pr<strong>of</strong>iles with a varying or even a partial
corrugation geometry are conceivable (Fig.
8 b), which would result in graded bending
rigidity or torsional stiffness properties.
Conclusion
Two strategies for <strong>the</strong> manufacturing <strong>of</strong> products,
or ra<strong>the</strong>r semi-finished products, with
locally adapted geometrical properties were
developed. Due to geometric limitations and
accessibilities <strong>of</strong> <strong>the</strong> cross section <strong>the</strong> technology
<strong>of</strong> integrated processing <strong>of</strong> open and hollow
pr<strong>of</strong>iles by forming is different.
For open sections a rolling setup for corrugating
<strong>the</strong> web <strong>of</strong> an I-beam section subsequent
to hot extrusion was developed and
tested. Future work will focus on <strong>the</strong> extension
<strong>of</strong> <strong>the</strong> geometrical complexity <strong>of</strong> <strong>the</strong> products
and on <strong>the</strong> analysis <strong>of</strong> <strong>the</strong> geometrical, mechanical
and resulting structural properties.
Experiments were conducted on hollow
pr<strong>of</strong>iles which were compressed by electromagnetic
forming subsequent to extrusion.
Due to an extremely short processing time <strong>of</strong>
<strong>the</strong> high speed forming process, a compensation
<strong>of</strong> <strong>the</strong> relative speed between <strong>the</strong> workpiece
and <strong>the</strong> tooling can be ignored. By <strong>the</strong>
contactless force induction, an additional benefit
is given for <strong>the</strong> heat balance. To fur<strong>the</strong>r
understand this process, analysis <strong>of</strong> process
dependencies in <strong>the</strong> system workpiece, field
shaper and mandrel is necessary.
Fig. 7: (a) Longitudinal cut, (b) cross section, (c) crack
Acknowledgement
This work was carried out in <strong>the</strong> subproject
TPA2 within <strong>the</strong> Transregional Collaborative
Research Centre SFB/TR30, funded by <strong>the</strong>
German Research Foundation (DFG).
References
Fig. 8: Corrugated web beam, a) continuously corrugate, b) partly corrugated
DIN 8583-6, 2003. Manufacturing processes forming
under compressive conditions – Part 6: Extrusion;
Classification, subdivision, terms and definitions,
Beuth, Berlin.
Guist, L.R., Marble, D.P., 1966. Prediction <strong>of</strong> <strong>the</strong>
inversion load. NASA
Technical Note 3622.
Golovashchenko, S.,
Dmitriev, V., Canfield,
P., Krause, A., Maranville,
C., 2006. Patent
application US
2006/0086165A1.
Apparatus for electromagnetic
forming with
durability and efficiency
enhancement.
Hahn, R., 2004.
Werkzeuge zum impulsmagnetischenWarmfügen
von Pr<strong>of</strong>ilen aus
Aluminium- und Magnesiumlegierungen,doctoral
<strong>the</strong>sis, Technische
Universität Berlin.
Hall, D. D., Mudawar, I.,
EXTRUSION
1996. Optimization <strong>of</strong> quench history <strong>of</strong> <strong>aluminium</strong>
parts for superior mechanical properties, International
Journal <strong>of</strong> Heat and Mass Transfer 39 (1),
p. 81-95.
Harvey, G. W., Brower, D. F., 1961. US patent 2 976
907. Metal forming device and method, 28 March.
Jäger, A., Risch, D., Tekkaya, A. E., 2009. Patent
application DE 10 2009 039 759 A1. Verfahren und
Vorrichtung zum Strangpressen und nachfolgender
elektromagnetischer Umformung, 31 August.
Jäger, A., Risch, D., Tekkaya, A. E., 2011a. Thermomechanical
processing <strong>of</strong> <strong>aluminium</strong> pr<strong>of</strong>iles by
integrated electromagnetic compression subsequent
to hot extrusion, Journal <strong>of</strong> Materials Processing
Technology 211 (5), Special Issue: Impulse Forming,
p. 936-943.
Jäger, A., Ben Khalifa, N., Psyk, V., Tekkaya, A.
E. 2011b. Thermo-mechanical processing <strong>of</strong> <strong>aluminium</strong>
pr<strong>of</strong>iles subsequent to hot extrusion, steel
research international, Special edition: International
Conference on Technology <strong>of</strong> Plasticity,
ICTP, 2011, Aachen, Germany
Laue, K. Stenger, H., 1976. Strangpressen, Aluminium
Verlag, Düsseldorf, p. 1. Ostermann, F.,
2007. Anwendungstechnologie Aluminium, 2nd
Edition. Springer, Berlin, p. 440-441.
Authors
Dipl.-Ing. Andreas Jäger is head <strong>of</strong> <strong>the</strong> department
<strong>of</strong> bulk metal forming at <strong>the</strong> Institute <strong>of</strong> Forming
Technology and Lightweight Construction (IUL).
Dipl.-Ing. Nooman Ben Khalifa is chief engineer for
research at <strong>the</strong> IUL.
Pr<strong>of</strong>. Dr.-Ing. A. Erman Tekkaya is head <strong>of</strong> <strong>the</strong> IUL.
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