The numbers used to describe aluminum wrought alloys conform to a code developed by the ALUMINUM ASSOCIATION. The first four figures in the grouping describe the alloys used. Other code figures or letters indicate the form of the product and the type of heat-treatment given.<\/p>\n
Four Digit Numerical Designations<\/p>\n
1st Digit \u2013 Indicates alloy group.<\/p>\n
2nd Digit \u2013 Indicates modifications in impurity limits.<\/p>\n
3rd & 4th Digits \u2013 Identify the different alloys in a group.<\/p>\n
Alloy Groups<\/p>\n
Alloy Number Major Alloying Elements<\/p>\n
1 XXX \u2013 Aluminum \u2013 99.00% minimum and greater<\/p>\n
2 XXX \u2013 Copper<\/p>\n
3 XXX \u2013 Manganese<\/p>\n
4 XXX \u2013 Silicon<\/p>\n
5 XXX \u2013 Magnesium<\/p>\n
6 XXX \u2013 Magnesium & Silicon<\/p>\n
7 XXX \u2013 Zinc<\/p>\n
8 XXX \u2013 Other elements<\/p>\n
9 XXX \u2013 Unused series<\/p>\n
The letter \u201cX\u201d preceding a 4 digit series indicates experimental \u2013 Example \u2013 X7004.<\/p>\n
Tempers<\/p>\n
These designations follow the above alloy numbers.<\/p>\n
F \u2013 as fabricated \u2013 Products which have no special control over final temper.<\/p>\n
O \u2013 Annealed<\/p>\n
H\u2013 Strain-hardened \u2013 where increased strength is obtained by cold work.<\/p>\n
T \u2013 Thermally treated to produce stable tempers other than \u201cF\u201d, “O\u201d or “H\u201d.<\/p>\n
W \u2013 Solution heat treated resulting in an unstable temper.<\/p>\n
Subdivision of H. Temper<\/p>\n
The first digit following an H indicates the specific combination of basic operations:<\/p>\n
H1 \u2013 Strain-hardened only.<\/p>\n
H2 \u2013 Strain-hardened and partially annealed.<\/p>\n
H3 \u2013 Strain-hardened and stabilized.<\/p>\n
H4 \u2013 Strain-hardened and lacquered or painted.<\/p>\n
The second digit following an H indicates the degree of strain-hardening:<\/p>\n
H x 1 \u2013 Eighth hard<\/p>\n
H x 2 \u2013 Quarter hard<\/p>\n
H x 4 \u2013 Half hard<\/p>\n
H x 6 \u2013 Three-quarter hard<\/p>\n
H x 8 \u2013 Hard<\/p>\n
H x 9 \u2013 Extra hard<\/p>\n
A third digit is sometimes used when the degree of control of temper or mechanical properties are different from but close to those for the two-digit H temper designation.<\/p>\n
H111 \u2013 Applies to products, which are strain hardened less than the amount required for a controlled H11 temper.<\/p>\n
H112 \u2013 Applies to products, which acquire some temper from shaping processes not having special control over the amount of strain hardening or thermal treatment, but for which there are mechanical property limits.<\/p>\n
H311 \u2013 Applies to products, which are strain-hardened less than the amount required for a controlled H31 temper.<\/p>\n
H321 \u2013 Applies to products, which are strain-hardened less than the amount required for a controlled H32 temper.<\/p>\n
H323-H343 \u2013 Applies to products, which are specially fabricated to have acceptable resistance to stress corrosion cracking.<\/p>\n
Subdivisions of T Temper<\/p>\n
T1 \u2013 Cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition.<\/p>\n
T2 \u2013 Annealed (cast products only).<\/p>\n
T3\u2013 Solution heat-treated and then cold worked.<\/p>\n
T4 \u2013 Solution heat-treated and naturally aged to a substantially stable condition.<\/p>\n
T5 \u2013 Cooled from an elevated temperature shaping process and then artificially aged.<\/p>\n
T6 \u2013 Solution heat-treated and then artificially aged.<\/p>\n
T7 \u2013 Solution heat-treated and then over aged\/stabilized.<\/p>\n
T8 \u2013 Solution heat-treated, cold worked, and then artificially aged.<\/p>\n
T9 \u2013 Solution heat-treated, artificially aged, and then cold worked.<\/p>\n
T10\u2013 Cooled from an elevated temperature shaping process, cold worked and then artificially aged. Additional digits may be added to indicate a variation in treatment, which significantly alters the characteristics of the product.<\/p>\n
T x 51 \u2013 Stress-relieved by stretching.<\/p>\n
T x 510 \u2013 Products that receive no further straightening after stretching.<\/p>\n
T x 511\u2013 Products that may receive minor straightening after stretching to comply with standard tolerances.<\/p>\n
T x 52 \u2013 Stress-relieved by compressing<\/p>","protected":false},"excerpt":{"rendered":"
The numbers used to describe aluminum wrought alloys conform to a code developed by the ALUMINUM ASSOCIATION. The first four figures in the grouping describe the alloys used. Other code figures or letters indicate the form of the product and the type of heat-treatment given. Four Digit Numerical Designations 1st Digit \u2013 Indicates alloy group. 2nd Digit \u2013 Indicates modifications<\/p>\n