A.
Wrought Aluminum and Aluminum Alloy Designation System
A four-digit numerical designation system is used to identify wrought aluminum and aluminum alloys. As shown below, the first digit of the four-digit designation indicates the group:
Aluminum, 99.00% 1xxx
Aluminum alloys grouped by major alloying element(s):
Copper 2xxx
Manganese 3xxx
Silicon 4xxx
Magnesium 5xxx
Magnesium and silicon 6xxx
Zinc 7xxx
Other elements 8xxx
Unused series 9xxx
For the 2xxx through 7xxx series, the alloy group is determined by the alloying element present in the greatest mean percentage. An exception is the 6xxx series alloys in which the proportions of magnesium and silicon available to form magnesium silicide (Mg2Si) are predominant. Another exception is made in those cases in which the alloy qualifies as a modification of a previously registered alloy. If the greatest mean percentage is the same for more than one element, the choice of group is in order of group sequence: copper, manganese, silicon, magnesium, magnesium silicide, zinc, or others.
Aluminum. In the 1xxx group, the series 10xx is used to designate unalloyed compositions that have natural impurity limits. The last two of the four digits in the designation indicate the minimum aluminum percentage. These digits are the same as the two digits to the right of the decimal point in the minimum aluminum percentage when expressed to the nearest 0.01%. Designations having second digits other than zero (integers 1 through 9, assigned consecutively as needed) indicate special control of one or more individual impurities.
Aluminum Alloys. In the 2xxx through 8xxx alloy groups, the second digit in the designation indicates alloy modification. If the second digit is zero, it indicates the original alloy; integers 1 through 9, assigned consecutively, indicate modifications of the original alloy. Explicit rules have been established for determining whether a proposed composition is merely a modification of a previously registered alloy or if it is an entirely new alloy. The last two of the four digits in the 2xxx through 8xxx groups have no special significance, but serve only to identify the different aluminum alloys in the group.
B.
Cast Aluminum and Aluminum Alloy Designation System
A system of four-digit numerical designations incorporating a decimal point is used to identify aluminum and aluminum alloys in the form of castings and foundry ingot. The first digit indicates the alloy group:
Aluminum, 99.00% 1xx.x
Aluminum alloys grouped by major alloying element(s):
Copper 2xx.x
Silicon, with added copper and/or magnesium 3xx.x
Silicon 4xx.x
Magnesium 5xx.x
Zinc 7xx.x
Tin 8xx.x
Other elements 9xx.x
Unused series 6xx.x
For 2xx.x though 8xx.x alloys, the alloy group is determined by the alloying element present in the greatest mean percentage, except in cases in which the composition being registered qualifies as a modification of a previously registered alloy. If the greatest mean percentage is common to more than one alloying element, the alloy group is determined by the element that comes first in the sequence.
The second two digits identify the specific aluminum alloy or, for the aluminum (1xx.x) series, indicate purity. The last digit, which is separated from the others by a decimal point, indicates the product form, whether casting or ingot. A modification of an original alloy, or of the impurity limits for unalloyed aluminum, is indicated by a serial letter preceding the numerical designation. The serial letters are assigned in alphabetical sequence starting with A but omitting I, O, Q, and X, the X being reserved for experimental alloys. Explicit rules have been established for determining whether a proposed composition is a modification of an existing alloy or if it is a new alloy.
Aluminum Castings and Ingot. For the 1xx.x group, the second two of the four digits in the designation indicate the minimum aluminum percentage. These digits are the same as the two digits to the right of the decimal point in the minimum aluminum percentage when expressed to the nearest 0.01%. The last digit indicates the product form: 1xx.0 indicates castings, and 1xx.1 indicates ingot.
Aluminum Alloy Castings and Ingot. For the 2xx.x through 9xx.x alloy groups, the second two of the four digits in the designation have no special significance but serve only to identify the different alloys in the group. The last digit, which is to the right of the decimal point, indicates the product form: xxx.0 indicates castings, and xxx.1 indicates ingot having limits for alloying elements the same as those for the alloy in the form of castings, except for those listed in Table 1.
Table 1 Alloying element and impurity specifications for ingots that will be remelted into sand, permanent mold, and die castings
Alloying element Composition, wt%
Casting Ingot
Sand and permanent mold Die All
Iron 0.15 . . . . . . Casting -0.03
>0.15-0.25 . . . . . . Casting -0.05
>0.25-0.6 . . . . . . Casting -0.10
>0.6-1.0 . . . . . . Casting -0.2
>1.0 . . . . . . Casting -0.3
. . . 1.3 . . . Casting -0.3
. . . >1.3 . . . 1.1
Magnesium . . . . . . <0.50 Casting +0.05(a)
. . . . . . 0.50 Casting +0.1(a)
Zinc . . . >0.25 to 0.60 . . . Casting -0.10
. . . >0.60 . . . Casting -0.1
C.
Composition of wrought unalloyed aluminum and wrought aluminum alloys
Grade designation Composition, wt%
Aluminum
Association UNS No. ISO No.
R209 Si Fe Cu Mn Mg Cr Ni Zn Ga V Specified
other
elements Ti Unspecified
other
elements Al,
6061 A96061 AlMg1SiCu 0.40-0.8 0.7 0.15-0.40 0.15 0.8-1.2 0.04-0.35 . . . 0.25 . . . . . . . . . 0.15 0.05 0.15 rem
A97005 . . . 0.35 0.40 0.10 0.20-0.7 1.0-1.8 0.06-0.20 . . . 4.0-5.0 . . . . . . 0.08-0.20 Zr 0.01-0.06 0.05 0.15 rem
D.
AAI ISO Designation name
6061 Al Mg1SiCu
7005 Al Zn4.5Mg1.5Mn
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