ssc-452 aluminum structure design and fabrication guide ship

Aluminum Marine Structure Guide
Table 2-1 Chemical Composition of Aluminum Alloys (Percentage by weight)
Alloy Si Fe Cu Mn Mg Cr Zn Ti Zr
5052 0.25 0.40 0.10 0.10 2.2-2.8 0.15-0.35 0.10 - xx
5059 0.45 0.50 0.25 0.60-1.2 5.0-6.0 0.25 0.40-0.90 0.20 xx
5083 0.40 0.40 0.10 0.40-1.0 4.0-4.9 0.05-0.25 0.25 0.15 xx
5086 0.40 0.50 0.10 0.20-0.70 3.5-4.5 0.05-0.25 0.25 0.15 xx
5383 0.25 0.25 0.20 0.7-1.0 4.0-5.2 0.25 0.40 0.15 xx
5454 0.25 0.40 0.10 0.50-1.00 2.4-3.0 0.05-0.20 0.25 0.20 xx
5456 0.25 0.40 0.10 0.50-1.00 4.7-5.5 0.05-0.20 0.25 0.20 xx
6005A .50-.90 0.35 0.3 0.5 .40-.70 0.3 0.2 0.1 xx
6061 .40-.80 0.7 .15-.40 0.15 .80-1.20 0.04-0.35 0.25 0.15 xx
6063 0.20-0.60 0.35 0.10 0.10 0.45-0.90 0.10 0.10 0.10 xx
6082 0.7-1.3 0.50 0.1 0.40-1.0 0.6-1.2 0.25 0.20 0.10 xx
2.1.2 Alloy and Temper Designations
The Aluminum Association has a numbering system for aluminum wrought products that
consists of 4-digit number followed by a letter and then additional numbers. The first four
numbers refer to the chemical composition of the alloy, and the letter and following number
indicates the temper. Properties are defined by the alloy and its temper. An alloy can be
processed to a variety of tempers, which can have varied properties. This designation system is
now internationally accepted and has largely replaced the former numbering schemes that varied
from country to country (Aluminum Association, 2005A).
The alloys that have 5 as the first digit of their alloy designation, (i.e. the 5xxx-series)
have magnesium as the principal alloying agent, and many also may have a significant amount of
manganese. The 5xxx-series are not heat-treatable, but obtain additional strengthening by work
hardening. The alloys with a 6 as the first digit, the 6xxx series, have magnesium and silicon as
principal alloying agents. These form magnesium silicide, which makes the alloys heattreatable.
The remaining three digits represent the specific alloy composition.
In an aluminum alloy, the 4-digit alloy designation is followed by a letter and several
numbers to indicate the temper of the alloy. The letter H indicates strain hardening, and T
indicates heat treatment. For strain-hardened alloys, such as those in the 5xxx series, a 1
following the H indicates that the alloy is only strain hardened. If the digit is 2, the alloy is strain
hardened and then slightly annealed, and if the first digit is a 3, the alloy is strain hardened and
then has the properties stabilized by either low-temperature treatment, or by heat introduced
during fabrication.
The second digit in the H-tempers relates to the degree of strain hardening above the
annealed temper, with 8 typically indicating the greatest hardening normally produced. The third
digit indicates a variant of the 2-digit temper. A formal system for indicating the degree of
hardening by which the ultimate strength of an alloy can be estimated was introduced by the
Aluminum Association in 1992. However, alloys developed before 1992 do not have to comply
with that system.
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