ASM Handbook, Volume 2: Properties and Selection: Nonferrous Alloys and Special-Purpose Materials Copyright © 1990 ASM International® ASM Handbook Committee, p 15-28 All rights reserved. DOI: 10.1361/asmhba0001058 www.asminternational.org Alloy and Temper Designation Systems for Aluminum and Aluminum Alloys R.B.C. Cayless, Alcan Rolled Products Company SYSTEMS FOR DESIGNATING alumi- est mean percentage is the same for more Aluminum, ->99.00%............................. lxx.x num and aluminum alloys that incorporate than one element, the choice of group is in Aluminum alloys grouped by major alloying the product form (wrought, casting, or order of group sequence: copper, manga- element(s): foundry ingot), and its respective temper nese, silicon, magnesium, magnesium sili- Copper ......................................... 2xx.x Silicon, with added copper and/or (with the exception of foundry ingots, cide, zinc, or others. magnesium .................................. 3xx.x which have no temper classification) are Aluminum. In the lxxx group, the series Silicon ......................................... 4xx.x covered by American National Standards lOxx is used to designate unalloyed com- Magnesium .................................... 5xx.x Institute (ANSI) standard H35.1. The Alu- positions that have natural impurity limits. Zinc ............................................ 7xx.x Tin ............................................. 8xx.x minum Association is the registrar under The last two of the four digits in the Other elements ................................ 9xx.x ANSI H35.1 with respect to the designation designation indicate the minimum alumi- Unused series .................................... 6xx.x and composition of aluminum alloys and num percentage. These digits are the same tempers registered in the United States. as the two digits to the right of the decimal point in the minimum aluminum percent- For 2xx.x through 8xx.x alloys, the alloy age when expressed to the nearest 0.01%. group is determined by the alloying element Wrought Aluminum Designations having second digits other present in the greatest mean percentage, and Aluminum Alloy than zero (integers 1 through 9, assigned except in cases in which the composition Designation System consecutively as needed) indicate special being registered qualifies as a modification A four-digit numerical designation system control of one or more individual impuri- of a previously registered alloy. If the great- is used to identify wrought aluminum and ties. est mean percentage is common to more aluminum alloys. As shown below, the first Aluminum Alloys. In the 2xxx through than one alloying element, the alloy group is digit of the four-digit designation indicates 8xxx alloy groups, the second digit in the determined by the element that comes first the group: designation indicates alloy modification. If in the sequence. the second digit is zero, it indicates the The second two digits identify the specif- original alloy; integers 1 through 9, assigned ic aluminum alloy or, for the aluminum Aluminum, ->99.00%.............................. lxxx consecutively, indicate modifications of the (lxx.x) series, indicate purity. The last digit, Aluminum alloys grouped by major alloying element(s): original alloy. Explicit rules have been es- which is separated from the others by a Copper.......................................... 2xxx tablished for determining whether a pro- decimal point, indicates the product form, Manganese ...................................... 3xxx posed composition is merely a modification whether casting or ingot. A modification of Silicon .......................................... 4xxx of a previously registered alloy or if it is an an original alloy, or of the impurity limits Magnesium ..................................... 5xxx Magnesium and silicon ......................... 6xxx entirely new alloy. The last two of the four for unalloyed aluminum, is indicated by a Zinc ............................................. 7xxx digits in the 2xxx through 8xxx groups have serial letter preceding the numerical desig- Other elements ................................. 8xxx no special significance, but serve only to nation. The serial letters are assigned in Unused series ..................................... 9xxx identify the different aluminum alloys in the alphabetical sequence starting with A but group. omitting I, O, Q, and X, the X being re- served for experimental alloys. Explicit For the 2xxx through 7xxx series, the rules have been established for determining alloy group is determined by the alloying whether a proposed composition is a modi- element present in the greatest mean per- Cast Aluminum and Aluminum fication of an existing alloy or if it is a new centage. An exception is the 6xxx series Alloy Designation System alloy. alloys in which the proportions of magne- A system of four-digit numerical desig- Aluminum Castings and Ingot. For the sium and silicon available to form magne- nations incorporating a decimal point is lxx.x group, the second two of the four sium silicide (MgzSi) are predominant. An- used to identify aluminum and aluminum digits in the designation indicate the mini- other exception is made in those cases in alloys in the form of castings and foundry mum aluminum percentage. These digits are which the alloy qualifies as a modification ingot. The first digit indicates the alloy the same as the two digits to the right of the of a previously registered alloy. If the great- group: decimal point in the minimum aluminum 16 / Specific Metals and Alloys Table 1 Alloyingelement and impurity specifications for ingots that will be remelted 6181=A1 SilMg0.8 into sand, permanent mold, and die castings The chemical symbols for addition ele- [ Composition, wt% ments should be limited to four: I Casting l Alloying element ~Sand and permanent mold Die All Ingot 7050=A1 Zn6CuMgZr Iron ........................ -<0.15 Casting -0.03 >0.15-0.25 Casting -0.05 If an alloy cannot otherwise be distin- >0.25-0.6 Casting -0.10 guished, a suffix in brackets is used: >0.6-1.0 Casting -0.2 >1.0 Casting -0.3 6063=A1 Mg0.7Si <-1.3 Casting -0.3 >1.3 -<l.1 6463 =A1 Mg0.7Si(B) Magnesium.................. • • <0.50 Casting +0.05(a) ->0.50 Casting +0.1(a) and international alloy registration Zinc ........................ • • >0.25 to 0.60 Casting -0.10 >0.60 Casting -0.1 6063A=A1 Mg0.7Si(A) (a) Applicable only when the specified range for castings is >0.15% Mg. Source: Ref I Note that suffixes (A), (B), and so on, should not be confused with suffixes of the percentage when expressed to the nearest organizations are signatories of a Declara- Aluminum Association. 0.01%. The last digit indicates the product tion of Accord on the Recommendation for The proposed ISO chemical composition form: lxx.O indicates castings, and lxx.1 an International Designation System for standard for aluminum and its alloys refer- indicates ingot. Wrought Aluminum and Wrought Alumi- ences Aluminum Association equivalents as Aluminum Alloy Castings and Ingot. For num Alloys. In addition to the United well as its own identification system. A the 2xx.x through 9xx.x alloy groups, the States, the countries represented by signa- listing of these is given in Table 4. second two of the four digits in the designa- tories are Argentina, Australia, Austria, European Committee for Standardization. tion have no special significance but serve Belgium, Brazil, Denmark, Finland, This committee (Comit6 Europren de Nor- only to identify the different alloys in the France, Germany, Italy, Japan, Nether- malisation, CEN) of European Common group. The last digit, which is to the right of lands, Norway, Spain, Sweden, Switzer- Market members has developed a composi- the decimal point, indicates the product land, South Africa, and the United King- tion standard based on the ISO standard, but form: xxx.O indicates castings, and xxx.1 dom. The European Aluminum Association is proposing new designations not included in indicates ingot having limits for alloying is also a signatory. that standard. Some of these new designa- elements the same as those for the alloy in Under ANSI standard H35.1, wrought tions are already registered as German (Deut- the form of castings, except for those listed aluminum or aluminum alloys will be regis- sche Industrial-Normen, DIN) standards. in Table 1. tered in decreasing priority as national vari- The proposed standard also references Alu- ations, as modifications, or as a new four- minum Association equivalents. Designations for digit number. A national variation that has composition limits very close but not iden- Temper Designation System for Experimental Alloys tical to those registered by another country Experimental alloys also are designated is identified by a serial letter following the Aluminum and Aluminum Alloys in accordance with the systems for wrought numerical designation. The temper designation system used in and cast alloys, but they are indicated by Castings and Foundry Alloys. There is no the United States for aluminum and alumi- the prefix X. The prefix is dropped when similar international accord for these alumi- num alloys is used for all product forms the alloy is no longer experimental. During num or aluminum alloy products. (both wrought and cast), with the exception development and before they are designated Foreign Alloy Designations. Historically, of ingot. The system is based on the se- as experimental, new alloys may be identi- all major industrialized countries developed