Cladding which is a sacrificial aluminum coating applied to an aluminum alloy core for the purpose of
increasing corrosion resistance is designated as alclad 2024, alclad 2014, alclad 7075, etc.
3-7. Aluminum alloys for military use are identified by military and federal specifications which are comparable to commercial
specifications and designations.
The following table is a general list of the commonly used military and federal specifications according to the commercial designation
and forms of material.
3-8. MECHANICAL PROPERTIES. Prior to presenting factual data on mechanical properties the tempers (hardness) and methods
of designation should be explained. For nominal mechanical properties see Table 3-4.
3-9. The tempers of aluminum alloys are produced essentially by three methods. These methods are cold working (strain
hardening), heat treatment and a combination of the two. The various alloys of aluminum are either classed as heat-treatable or non-
heat-treatable. Alloys 1100, 3003, alclad 3003, 3004, alclad 3004, 5050 and 5052 are classed as nonheat-treatable.
The tempers of these alloys are designated by symbols H1, H2, H3, H4, F & 0.
3-10. A second number added to the above indicates the degree of strain hardening-actual temper.
2=¼ hard (2/8) H12, H22, H32
4=½ hard (4/8) H14, H24, H34
6=¾ hard (6/8) H16, H26, H36
8=Full Hard (8/8) H18, H28, H38
As previously pointed out the above tempers designation symbols are hyphen (-dash) suffixed to the 4 digit alloy designation.
Example: 1000-H12, 5052-H24, 3004-H34 etc. The general symbols used for the non-heat-treatable alloys are as follows:
-F As fabricated
-H21 Strain hardened only
-H2 Strain hardened then partial annealed
-H3 Strain hardened then stabilized
Attempt should not be made to alter the temper characteristics of the "H" series of aluminum alloys
other than in emergencies. This shall be limited to annealing operation only.
3-11. Alloys alclad 2014, 2024, alclad 2024, 8061, 7075, alclad 7075 and 7178 are classed as heat treatable. The mechanical
properties of these alloys is improved by heat treatment or by a combination of heat treatment and strain hardening. The tempers for
these alloys is designated by symbols, W, T, T2, T3, T4, T5, TO, T7, T8, T9, T10, F & O. Following is a summery of these symbols.
-F As fabricated
-W Solution heat treated unstable temper
-T Treated to produce stable tempers other than -F or -O
-T2 Annealed (cast products only)
-T3 Solution heat treated and then cold worked
-T4 Solution heat treated -T5 Artificially aged only
-T6 Solution beat treated and then artificially aged
-T7 Solution heat treated and stabilized
-T8 Solution heat treated, cold worked and then artificially aged
-T9 Solution heat treated, artificially aged, and then cold worked
-T10 Artificially aged and then cold worked
Added numbers to the above denotes a modification of standard tempers. Example: The numeral "6" following "T3" indicates a
different amount of cold work than used in "T3" such as 2024-T36. The numbers added to indicate modification or significant
alternation of the standard temper are arbitrarily assigned and specification for the alloy should be utilized to determine specific data.
3-12. The following standard modification digits have been assigned for wrought products in all alloys: TX-51 Stress-Relieved by
Stretching: Applies to products which are stress-relieved by stretching the following amounts after solution heat treatment:
1 ½ to 3% permanent set
Rod, Bar and Shapes
1 to 3% permanent set
Applies directly to plate and rolled or cold finishes rod and bar. These products receive no further straightening after stretching.
Applies to extruded rod, bar and shapes which receive minor straightening after stretching to comply with standard tolerances.
-TX510 Applies to extruded rod, bar and shapes which receive no further straightening after stretching.
-TX511 Applies to extruded rod, bar and shapes which receive minor straightening after stretching to comply with standard