Aluminium Design and Construction John Dwight

CHAPTER 4
Aluminium alloys and their
properties
4.1 NUMBERING SYSTEM FOR WROUGHT ALLOYS
4.1.1 Basic system
The American system for designating wrought aluminium materials,
administered by the Aluminum Association (AA) in Washington, is by
now virtually standard worldwide [12]. For any given material, it employs
a two-part reference number, e.g. 3103–H14, 6082–T6 or 5083–0. The
four-figure number before the hyphen defines the alloy, and the symbols
after it the condition (or temper) in which that alloy is supplied.
Aluminium alloys can be either non-heat-treatable or heat-treatable.
The former are available in a range of work-hardened conditions, defined
by an H-number (as in the first example above), while the latter are
supplied in various conditions of heat treatment, specified in terms of
a T-number (second example).
4.1.2 Standardization of alloys
The four-figure number before the hyphen relates to a chemical
composition, i.e. an alloy. The AA supply a document (Registration Record
of International Alloy Designations) which lists the reference numbers of
all the alloys registered with them, together with their compositions.
The list runs to several hundred and is regularly updated. The new
European (EN) standards have adopted the same alloy numbers, but
prefixed by the letters AW (Aluminium Wrought). Thus, in the European
system, 6082 alloy is officially referred to as AW-6082, although in common
speech it is normal to omit the AW.
The following illustrates the way in which a composition is specified,
using the alloy 6082 as an example:
Si Mn Mg Fe Cu Cr Zn
0.7–1.3 0.4–1.0 0.6–1.2 0.5 0.1 0.25 0.2 %
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