Abstract
The cold-rolling process is a complex dynamic strain-hardening mechanism that is known
for its strength improvement, excellent surface finish and dimensional tolerance. Cold
rolling, a metal deformation process, is characterized by forming temperatures below the
recrystallization temperature of the rolled workpiece, usually metals. Cold rolling of
aluminium 8015-alloy involves deformation of the alloy metal by the use of rolls achieved
in cold rolling mills to produce metal sheets of a certain thickness specified by the end users
for packaging, automotive, and construction/structural applications.
Previous studies have reported large amount of research achieved on aluminium and its
alloys; however, extensive work has not been accomplished on the 8-series family, especially
on aluminium 8015-alloy that is processed by rolling. Likewise, scholars have not
comprehensively exploited the cold rolling process, particularly the thermal analysis
involved in cold rolling. This has been due to the widespread assumption of its insignificant
impact during the cold rolling process. In addition, the material model utilized in the finite
element simulation of the metal forming processes, are often a variety of constitutive
equations that are either phenomenological, or to a varying degree physically based – due to
the complex behaviour of the material.
This study is industrially based, with the objective of investigating the structural integrity of
the rolled aluminium 8015-alloy. The research is centred on two aspects intending to provide
increased knowledge to hands-on engineers and researchers in the rolling industry. On the
one hand, experimental studies on the mechanical, metallography, and electrochemical
corrosion testing of hot- and cold-rolled aluminium 8015-alloy were examined by using the
Instron Universal Testing machine, the Vickers micro-hardness tester, optical and scanning
electron microscopes, and the Ivium potentiostat, in order to determine the effect of strain
hardening on the cold-rolled aluminium 8015-alloy in comparison to the hot-rolled alloy.
On the other hand, modelling and simulation of the cold rolling process further accounts for
the strong coupling of aluminium 8015-alloy strip plastic and the roll thermo-elastic
deformation in the industrial cold rolling process of aluminium 8015-alloy. Two-dimensional
and three-dimensional finite element models and its simulation were accomplished using
MSC Marc Mentat. The thermo-mechanical behaviour of aluminium 8015-alloy during the
industrial cold-rolling process was examined with a two-contact algorithm finite element
simulation. The finite element simulation contributed to the deformation and thermal...
D.Phil. (Mechanical Engineering)