Electrical
Conductors
Transport
Packaging
Building and
Architecture
Miscellaneous
Applications
High Pressure Gas
Cylinders
Machined Components
Ladders and Access
Equipment
Sporting Equipment
Road Barriers and Signs
Domestic and Office
Furniture
Lithographic
Plates
Wrought Aluminium Alloy Composition Limits
How to select a proper aluminum alloy
Electrical Conductors
Conductors in either the 1000 or 6000 series
alloys are sensible technical alternatives
to copper for all electrical conductors,
even in domestic wiring.
A very large proportion of overhead, high
voltage, power lines utilise aluminium
rather than copper as the conductor on
weight grounds. The relatively low strength
of these grades requires that they be
reinforced by including a galvanised or
aluminium coated high tensile steel wire in
each strand.
Aluminium alloys have a conductivity
averaging 62% of the International Annealed
Copper Standard (IACS) but, because of its
density, it can carry more than twice as
much electricity as an equivalent weight of
copper.
Transport
Aluminium and its alloys have been the prime
material of construction for the aircraft
industry throughout most of its history.
Even today, when titanium and composites are
growing in use, 70% of commercial civil
aircraft airframes are made from aluminium
alloys, and without aluminium civil aviation
would not be economically viable.
The combination of acceptable cost, low
component mass (derived from its low
density), appropriate mechanical properties,
structural integrity and ease of fabrication
are also attractive in other areas of
transport. There are now very many examples
of its use in commercial vehicles, rail cars
both passenger and freight, marine hulls and
superstructures and military vehicles.
Volume car production now includes aluminium
as engine castings, wheels, radiators and
increasingly as body parts. For general
production the 5000 and 6000 series alloys
provide adequate strength combined with good
corrosion resistance, high toughness and
ease of welding. In aircraft the very strong
2000, 7000 and 8000 series alloys are
preferred, and in military vehicles the
weldable 7000 series alloys can provide
ballistic properties to match steel armour.
Packaging
The successful use of the 1000 series alloys
as foil for food wrapping and for containers
utilises their good corrosion resistance and
barrier properties against UV light,
moisture and odour. Foil can be readily
formed, attractively decorated and can be
usefully combined with paper and plastic if
required.
The most significant use of aluminium in
packaging has been in the production of
beverage cans which incorporate the `easy
open ring pull' in the lid. This has rapidly
grown to some 15% of all aluminium
consumption, one hundred thousand million
cans a year!
Cans for some food products, particularly
fish, which also employ the easy opening
facilities of aluminium, have been used for
over sixty years. From a technical point of
view there is no reason why more use should
not be made of aluminium as a can material,
to date costs seem to be the restraining
factor. This may become less important in
the future, see the section on recycling.
Building and Architecture
Aluminium is used in buildings for a wide
spectrum of applications. These include
roofing for factories which incorporate foil
vapour barriers, windows and pre formed
sheet cladding features, doors, canopies and
fronts for shops and prestigious buildings,
architectural hardware and fittings,
rainwater goods and replacement windows.
Aluminium structures and cladding are also
used to refurbish many of the concrete
structures built in the 1950-60's which are
now showing signs of deterioration and
spoiling.
In building applications the durability of
aluminium is of paramount importance. There
are a number of good examples of the
durability of aluminium which may be
familiar to the reader including the statue
of Eros in Picadilly Circus, London erected
in 1893 and the clad dome of the church of
San Gioacchino in Rome installed in 1887.
More recently the oil and gas industry has
employed aluminium widely in offshore
structures.
The 1000, 3000, 5000 and 6000 wrought series
alloys will perform, with no reduction of
strength, without protection even in
industrial and marine environments. They may
however suffer some deterioration in their
appearance and protection by painting or
anodising can be advisable.
Anodised films may be clear, to preserve the
`aluminium' finish or in a limited range of
colours. Painting offers a wider range of
colours and an appearance similar to other
painted metals.
These finishing operations may also, of
course, be used for purely decorative
effects.
Miscellaneous Applications
The applications outlined above account for
some 85% of consumption. The remaining 15%
are consist mainly of the following
applications.
High
Pressure Gas Cylinders
Compressed gas cylinders with capacities up
to fifty litre capacity for storage and
transportation of CO2, air, oxygen and
special gases. The 6000 series alloys
combine light weight, good corrosion
resistance, compatibility with the product
to be contained and mechanical toughness.
Machined Components
High tolerance components can be machined
from the 2000 and 6000 series alloys. These
alloys have additions of lead and bismuth
which gives them machineability that
approaches that of the free machining
brasses.
Ladders and Access Equipment
Aluminium alloys are highly suited to
ladders and access equipment due to their
lightweight, corrosion resistance and
toughness. The 6000 series extrusions in
particular are used both industrially and
domestically.
Sporting Goods
The 2000 and 7000 series alloys are used for
golf clubs and trolleys, racquets for many
sports, snooker and pool cues, ski poles,
often employing spin off from aerospace
technology.
Road
Barriers and Signs
Extrusions and roll formed sheet in the 6000
and 5000 series alloys provide good
corrosion resistance and decorative ability.
Domestic and Office Furniture
The complexity and surface finish of
extrusions in the 6000 series alloys coupled
with the range of shapes from castings and
the use of superplastically formed sheet
allows designers almost unlimited scope.
Lithographic Plates
This is a high purity 1000 series sheet
product which has its surface
electrochemically grained then anodised to
generate the base to receive the coatings
used by printers
Wrought Aluminium Alloy Composition Limits
1000 series are essenitally pure aluminium
with a minimum 99% aluminium content by
weight and can be work hardened
2000 series are alloyed with copper, can be
precipitation hardened to strengths
comparable to steel. Formerly referred to as
duralumin, they were once the most common
aerospace alloys, but were susceptible to
stress corrosion cracking and are
increasingly replaced by 7000 series in new
designs.
3000 series are alloyed with manganese, and
can be work hardened
4000 series are alloyed with silicon. They
are also known as silumin
5000 series are alloyed with magnesium,
derive most of their strength from solution
hardening, and can also be work hardened to
strengths comparable to steel
6000 series are alloyed with magnesium and
silicon, are easy to machine, and can be
precipitation hardened, but not to the high
strengths that 2000, 5000 and 7000 can
reach.
7000 series are alloyed with zinc, and can
be precipitation hardened to the highest
strengths of any aluminium alloy.
8000 series are a miscellaneous category