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Aluminum Information
Common Grades
Wrought Alloys
Cast Alloys
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Wrought
Aluminum and Aluminum Alloy Designation System
A system for designating wrought aluminum and wrought
aluminum alloys was established by the Aluminum Association. The system
consists of four-digit numerical designations is used to identify wrought
aluminum and wrought aluminum alloys.
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The first digit
indicates the alloy group as follows: |
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1XXX |
Aluminum, 99.00% minimum and greater |
|
2XXX |
Copper (Cu). |
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3XXX |
Manganese (Mn) |
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4XXX |
Silicon (Si) |
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5XXX |
Magnesium (Mg) |
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6XXX |
Magnesium and Silicon (Mg and Si) |
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7XXX |
Zinc (Zn) |
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8XXX |
Other elements |
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9XXX |
Unused series |
In the 1XXX group for minimum aluminum purities of 99.00
percent and greater, the last two of the four digits in the designation
indicate the minimum aluminum percentage. These digits are the same as the
last two digits to the right of the decimal point in the minimum aluminum
percentage when it is expressed to the nearest 0.01 percent. The second
digit in the designation indicates modifications in impurity limits. If the
second digit is zero, it indicates unalloyed aluminum having natural
impurity limits; integers 1 through 9, which are assigned consecutively as
needed, indicate special control of the of more individual impurities or
alloying elements.
In
the 2XXX through 8XXX alloy groups the last two of the four digits in the
designation have no special significance but serve only to identify the
different aluminum alloys in group. The second digit in the alloy
designation indicates alloy modifications. If the second digit is zero, it
indicates the original alloy; integers 1 through 9, which are assigned
consecutively, indicate alloy modifications.
Temper
Designation System
The temper designation system is used for all forms of
wrought and cast aluminum and aluminum alloys except ingot. It is based on
the sequence of basic treatments used to produce various tempers. The temper
designation follows the alloy designation with the two separated by a
hyphen. Basic designations consist of a letter while subdivisions of those
basic tempers, where required, are indicated by one or more digits following
those letters. The system is designed to set down specific sequences of
fabrication processes, but only those operations that are recognized as
significantly influencing the characteristics of the product involved.
Should some other variation of the same sequence of basic operations be
applied to the same alloy, resulting in different characteristics, the
additional digits will be added to the numerical designation.
Temper
Designations Non-Heat Treatable Alloys
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F |
As fabricated. Denotes metal
that has been fabricated to ordered dimensions without any attempt on
the part of the producer to control the results of either
strain-hardening operations or thermal treatments. There are no
mechanical property limits, and the strength levels may vary form lot to
lot and from shipment to shipment. |
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O |
Annealed. Applies to wrought
products that have undergone a thermal treatment to reduce their
mechanical property levels to their minimums. Often described as "dead
soft" metal. |
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H |
Strain-hardened. Applies to
those wrought products which have had an increase in strength by
reduction through strain-hardening or cold working operations. The "H"
is always followed by two or more digits. |
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Subdivisions of "H" Temper-Non-Heat-Treatable Alloys |
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H1 |
Strain-hardened only. Applies to products which are strain-hardened or
cold worked to obtain the desired strength level without supplementary
thermal treatments. The number following this designation indicates the
degree of strain-hardening. |
| H2 |
Strain-hardened partially annealed. Applies to products strain-hardened
or cold worked more than the desired level by partial annealing. The
number following this designation indicates the degree of strain
hardening remaining after the partial annealing process. |
| H3 |
Strain-hardened and stabilized. Applies to products in the
magnesium-aluminum class which will age-soften at room temperature after
strain-hardening. These products are strain-hardened to the desired
amount and then subjected to a low temperature thermal operation which
results in a improved ductility. The number following this designation
indicates the degree of strain-hardening remaining after the
stabilization treatment. |
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The digit following the
designation H1, H2 or H3 indicates the degree of strain-hardening as
follows: |
| H_1 |
1/8 hard |
| H_2 |
1/4 hard |
| H_3 |
3/8 hard |
| H_4 |
1/2 hard |
| H_5 |
5/8 hard |
| H_6 |
3/4 hard |
| H_7 |
7/8 hard |
| H_8 |
full hard
(approximately 75% reduction after a full anneal). |
| H_9 |
extra hard
(limited to certain alloys and/or product forms). |
Temper
Designations Heat Treatable Alloys
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T |
Thermally
treated to produce tempers other than F, O or H. Applies to those
products which have had an increase in strength due to thermal
treatments, with or without supplementary strain-hardening operations.
The "T" is always followed by one or more digits. |
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W |
Solution
heat-treated. An unstable temper applying to certain of the (7XXX)
heat-treatable alloys that, after heat treatment, spontaneously age
harden at room temperature. Only when the period of natural aging is
indicated (W 1hr. for example) is this a specific and complete
designation. |
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Subdivisions of "T" Temper-Heat-Treatable Alloys |
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T1 |
cooled from
an elevated temperature shaping process and naturally aged to a
substantially stable condition. Usually associated with extruded
products and limited to the 6XXX series alloys. |
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T2 |
cooled from
an elevated temperature shaping process, cold worked, and naturally aged
to a substantially stable condition. Usually associated with cast
products. |
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T3 |
solution
heat-treated, cold worked, and naturally aged to a substantially stable
condition. (T4+cold work) |
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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 artificially aged. Usually
associated with extruded products in the 6XXX series alloys.
(T1+artificial age) |
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T6 |
solution
heat-treated, and artificially aged. (T4+artificial age) |
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T7 |
solution
heat-treated, and overaged/stabilized. Applies to alloy products which
are thermally overaged after solution heat-treatment to carry them
beyond the point of maximum strength to provide control of some special
characteristic. |
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T8 |
solution
heat-treated, cold worked, and artificially aged. (T3+artificial age) |
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T9 |
solution
heat-treated, artificially aged and cold worked. (T6+artificial age) |
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T10 |
cooled from
an elevated temperature shaping process, cold worked, and artificially
aged. Usually associated with cast products.(T2+artificial age) |
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The
following specific digits have been assigned for stress-relieved tempers
of wrought products: |
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T_51 |
Applies to
cold finished rod or bar when stress-relieved by stretching 1 to 3 %
permanent set. Stretching is performed after solution heat treatment or
after cooling from an elevated temperature shaping process. No
straightening takes place after stretching. |
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T_510 |
Applies to
extruded products and to drawn tube when stress-relieved by stretching 1
to 3 % permanent set. Stretching is performed after solution heat
treatment or after cooling from an elevated temperature shaping process.
No straightening takes place after stretching 1 to 3 % permanent set. |
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T_511 |
Applies to
extruded products and to drawn tube when stress-relieved by stretching 1
to 3 % permanent set. Stretching is performed after solution heat
treatment or after cooling from an elevated temperature shaping process.
These products may receive minor straightening after stretching to
comply with standard tolerances. |
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