Study on Metal Flow in Extruded Billet
Hideo Sano, Sumitomo Light Metal Industries, Ltd. and
Takashi Ishikawa and Yoshinori Yoshida, Nagoya University
Track: EXTRUSION PROCESS - Metal Flow
ABSTRACT --- Study on metal flow in extrusion billet is fundamental and useful to
understand extrusion technology. In particular, knowing extrusion billet skin behavior is
indispensable to maintain extrusion qualities. In order to investigate its behavior,
extrusion experiments of clad billet and the FE analysis by DEFORM-2DTM were
performed. Deformed shapes of billet skin were traced during extrusion by experiments
and FE analysis. The calculated behavior of billet skin was similar to that in
experiments. It was considered that the FE analysis results were acceptable to
estimate the actual metal flow behavior in extrusion. The billet skin penetrated the core
in indirect extrusion, and was piled up at the back end of billet in direct extrusion. A
dead metal zone appeared on the outer side of the die face in indirect extrusion, and
shear zone appeared between the dead metal zone and flow zone in direct extrusion.
Moreover, friction between back end of billet and stem affected the behavior of billet
skin. The penetration of skin in low friction coefficient was faster than that in high
friction coefficient in direct extrusion.
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