Abstract :
This paper reports on the application of numerical techniques to predict the initiation and
propagation of central burst defects in the wire drawing process. The development and implementation
of a suitable failure model into a commercial finite element code, via a user written subroutine,
has enabled the occurrence of ductile fracture by central bursting in 2011 Aluminium alloy wire to be
successfully analysed. In validating the numerical model, the drawing force, die pressure and occurrence
of central burst defects has been compared with previously published experimental data. Results
from the numerical model suggest that a ‘nose shape’ curve divides the safe and unsafe zones for the
successful drawing of the wire. It follows that no central bursts are expected to occur, regardless of
the die angle used, when the reduction ratio is less than a critical value. When central bursts did
occur, the effective strain was found to vary periodically along the surface of the wire. These oscillations
corresponded with the occurrence of central burst defects and resulted in variations in the final
diameter of the wire. These variations in the final diameter of the wire are thought to be representative
of an external defect known as ‘bamboo markings’, which are often an external indication of
central burst defects within the wire
