Prediction of Position and Extent of Charge Welds in Hollow Profile
Antonio Segatori, Barbara Reggiani, Lorenzo Donati, and Luca Tomesani,
University of Bologna, Bologna, Italy
Track: EXTRUSION/DIE THEORETICAL - Weld and Finite-Element Method
ABSTRACT—In billet-to-billet direct aluminum extrusion, the high hydrostatic pressure field
produces joining of the two consequent billets; however, the mechanical properties of the
transition zone are lower, thus requiring the scrapping of the charge-welded segment. The
localization of the segment to be discarded is a complex matter. This work aims to investigate the
interaction between the different welding phenomena inside an industrial multi-profile die, in
order to determine the exact position and the minimal profile length to be discarded. Experimental
investigations were performed on an industrial extrusion of four hollow profiles in EN AW-6060
alloy through a multi-hole die. Location and dimension of the charge weld was retrieved and
compared with finite element (FE) simulations of the process, thus evaluating the possibility of
using the code as a reliable tool for the localization and determination of the scrap, particularly if
new die design strategies must also be evaluated in terms of reduction of the zone extension.
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