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 Aluminum and its alloys are today considered one of the most
practical of metals for a variety
of reasons. Its low cost, light-weight, and modern appearance
are among the primary reasons
for its widespread use. It is non-sparking, electrically
conductive, thermally conductive, non-magnetic, reflective,
and chemically resistant. It is popular in the construction,
marine and aircraft industries because of its ease of
fabrication, non-toxicity, strength (pound-for
pound), and resistance to the corrosive atmospheres of
industry and marine environments.
Anodizing increases this corrosion resistance and also permits
iridescent finishes in different
colors. Some alloys are slightly corrosive and so are cladded
with a thin layer of aluminum
for added protection.
Apart from anodizing for the different iridescent finishes,
the surface of aluminum may
be changed by mechanical finishing and embossing, etching, and
electroplating. Machining
of aluminum is possible with great ease and speed. It can be
easily joined by riveting, welding,
brazing, or soldering.
The pound-for-pound strength aluminum possesses at least
equals, if not exceeds,
that of other metals. Greater strength can be gained by cold
working. Further strengthening
and hardening can be achieved by heat treatments-these
combinations being known as
tempers. Aluminum and its alloys may lose some strength at
elevated-temperatures,
but its
strength increases at low temperatures.
Major Alloying Element and Its Effect on Aluminum
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1000's - Aluminum 99% min. - excellent corrosion resistance,
high thermal and electrical conductivity, low mechanical
properties |
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2000's - Copper - high mechanical properties, increased
yield strength, best known and most widely used aircraft
alloy |
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3000's - Manganese - good workability and weldability, high
corrosion resistance, moderate strength |
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4000's - Silicon - low melting point, widely used in welding
wire and as a brazing alloy 5000's - Magnesium - moderate to
high strength, good welding characteristics, good resistance
to corrosion, especially in marine environments |
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6000's - Magnesium/Silicon - good formability and corrosion
resistance, moderate strength |
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7000's - Zinc - highest strength alloy available, used in
air-frame structures and for
highly stressed parts
8000's - Other element |
Aluminum Association
Alloy Designation System
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1st digit - Identifies alloy types. |
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2nd digit - Identifies alloy modifications. Digit replaces
letters formerly used. |
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3rd and 4th digits - Identifies the aluminum purity of the
specific aluminum alloy. |
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The digits are the same as the numbers in the old
designations for
alloys in use prior to the adoption of the four-digit
system. |
Temper Designations
H-Tempers: Strain-Hardened
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H1 - strain-hardened only. |
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H2 - strain-hardened and partially annealed. |
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H3 - strain-hardened and stabilized by low-temperature
thermal treatment. |
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The digit following H1, H2, or H3 indicates the
temper: |
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2 –1/4Hard |
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4 – 1/2 Hard |
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6 – 3/4 Hard |
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8 – Full Hard |
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9 – Extra Hard |
T-Tempers: Heat-Treated
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T1 - cooled from an elevated temperature shaping process
and naturally aged to a substantially stable condition |
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T2 - annealed (cast products only) |
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T3 - solution heat-treated and then cold worked |
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T4 - solution heat-treated and naturally aged to a
substantially stable condition |
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T5 - cooled from an elevated temperature shaping process
and then artificially aged |
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T6 - solution heat-treated and then artificially aged |
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T7 - solution heat-treated and then stabilized |
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T8 - solution heat-treated, cold worked, and then
artificially aged |
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T9 - solution heat-treated, artificially aged, and then
cold worked |
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T10 - cooled from an elevated temperature shaping process,
artificially aged and then cold worked |
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Additional digits for T tempers include the following: |
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T51-
stress relieved by stretching |
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T510-
receives no further straightening after stretching |
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T511-
receives minor straightening after stretching to comply
with standard tolerances |
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T52 – stress relieved by compressing |
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T54
– stress relieved by combined stretching and compressing |
1110
Being commercially pure aluminum, 1100 has excellent forming
qualities and work-hardens more slowly than other alloys. As
it is soft and ductile, 1100 is most often employed where
structural strength is not a primary requirement. It is
extremely resistant to corrosion, and therefore
finds excellent utilization in the chemical, cookware, and
food processing industries. It is
a non-heat treatable alloy.
Of all aluminum alloys, its thermal and electrical
conductivity is the highest. Its weldability is second to none
and it is commonly employed in the architectural field and
building trades.
Applications
Reflectors, cooking utensils and kitchenware, decorative
parts, giftware, dials, name-plates, tank cars, storage
tanks, chemical equipment, sheet metal work, heat
exchangers, and etc.
3003
3003 possesses the same basic characteristics and composition
of 1100, with the exception of
a greater percentage of manganese added to 3003. This addition
increases the strength of
this alloy by some 20% over that of commercially pure aluminum
(1100), It has excellent
workability, weld ability and resistance to corrosion. It may
be deep drawn or spun, brazed or
welded. This non-heat treatable alloy is among the most
commonly used alloys in industry today.
Applications
Drawn and spun parts,
ductwork, general sheet metal work, cooking utensils,
awnings and
sidings, decorative trim, garage doors, chemical equipment,
pressure vessels, heat exchangers,
and etc.
5052
5052 is extremely resistant to corrosion, particularly that of
a marine environment. It also possesses a high magnesium
content, making it the highest strength non-heat treatable
alloy available. It has good finishing characteristics, and
excellent workability. It is easily drawn or
welded, and may be formed into intricate shapes.
Applications
Sheet metal parts, aircraft components and tubes, small
boats, tankage, bus and truck bodies,
kitchen cabinets, cookware, appliances, fencing, fan blades,
food-processing equipment, and etc.
2024
2024, possessing both high strength and great fatigue
resistance, finds excellent usage in
parts and structures where a high strength-to-weight ratio is
desirable. It is a heat treatable
alloy, and use in this condition is recommended. Its
workability is good, and it may easily be
machined to high finishes. Its weldability is low, though it
may be flash, spot, or seam welded
if necessary. In the "Alclad" condition, its corrosion
resistance is excellent. If anodized, discoloration of this
alloy is possible because the high copper content "bleeds
through". This "bleeding through" is not harmful to the metal,
and does not alter its chemical or physical properties.
Applications
Bare
Aircraft parts, caul plates, scientific instruments, truck
wheels, fastening devices, and etc.
Alclad
Aircraft frames, fittings, and structural components, truck
bodies and parts, railroad car roofs and sides, caul plates,
and etc.
6061
6061 combines most of the good qualities of aluminum. It
possesses high strength, high resistance to corrosion, good
workability, and a wide range of mechanical properties. It is
the least expensive and most versatile of the heat treatable
alloys. 6061 in the annealed condition offers excellent
weldability and formability, and is readily disposed to
furnace brazing. It can be clad to offer higher corrosion
resistance. 6061-T6 plate is ASME Unfired Pressure Vessel Code
approved.
Applications
Marine equipment, boats, truck and bus bodies, tankage
and-tank fittings, structural components, screw machine
parts, high pressure applications, mine skips, transmission
towers, moldings, pipes, and etc.
  1075
The addition of a higher percentage of zinc to this alloy
makes 7075 one of the highest strength and hardest alloys
available. It finds its most common use in the aircraft
industry, especially where highly stressed parts are used. If
annealed, this alloy is highly formable and may be flash or
spot-welded. Heat-treating increases its strength
considerably. In the "Alclad" condition, 7075 is highly
resistant to corrosion.
Applications
7075 finds greatest utilization where extreme high strength
is required, especially in the aircraft industry.
Aluminum Tube
Aluminum tubing combines many diversified characteristics
suitable for industry. Qualities
such as corrosion resistance, electrical and thermal
conductivity, light weight, strength, ease
of fabrication, appearance and low cost predispose these
alloys for a wide range of applications.
Aluminum has capabilities for a wide range of finishes, and
anodizing offers finishes in
a variety-of iridescent colors. Because of its extremely high
ratio of strength-to-weight,
aluminum is a logical choice for construction and any product
that must be lifted, moved, or
flown. It is extremely popular in the aircraft and missile
industries.
Applications
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2024
- The most common heat treatable aluminum is 2024. It is
utilized where high strength and no welding is involved.
Aircraft fittings, structures, and hardware are some of
the major applications. |
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5052
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One of the strongest non-heat treatable aluminum alloys is
5052. Possessing excellent resistance to corrosion, good
workability and high fatigue strength, it is used
primarily for oxygen, fuel and oil lines. |
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6061
- The most common and least expensive of the heat
treatable aluminum alloys is 6061. Used where good
corrosion resistance and strength are needed, it can be
found applied in areas for welded assemblies, heat
exchangers and aircraft components. |
6061-T6
Aluminum Hydraulic Tubing
This grade is used primarily for hydraulic and pneumatic
systems that must operate under pressures of up to 3000 psi.
It is ideal for these applications as it is easily fabricated
and both surfaces are free from all foreign matter. It is a
sound and dense alloy possessing a wide range of mechanical
properties.
Aluminum Extruded Pipe
6061 and 6063 are heat treatable alloys possessing good
corrosion resistance. 6061 has as its major alloying elements
magnesium and silicon, making it versatile and weldable. 6063
contains additions of manganese and silicon, which increases
its corrosion resistance and workability, but lowers its
strength to slightly less than 6061.
Applications
Both 6061 -arid 6063 are used where the major requirements
are good corrosion resistance, a high strength-to-weight
ratio, and fairly good workability. 6063, because of its
excellent finishing properties, finds popular use in
architectural, furniture, and decorative applications.
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