Machinery's Handbook, 31st Edition
ALUMINUM AND Aluminum Alloys 529 The third digit, when used, indicates a variation of a two-digit -H temper, and is used when the degree of control of temper or the mechanical properties are different from but close to those for the two-digit -H temper designation to which it is added. ( Note: The minimum ultimate strength of a three-digit -H temper is at least as close to that of the corresponding two-digit -H temper as it is to the adjacent two-digit -H tempers.) Numerals 1 through 9 may be arbitrarily assigned and registered with the Aluminum Association for an alloy and product to indicate a specific degree of control of temper or specific mechanical property limits. Zero has been assigned to indicate degrees of control of temper or mechanical property limits negotiated between the manufacturer and purchaser that are not used widely enough to justify registration with the Aluminum Association. The following three-digit -H temper designations have been assigned for wrought prod ucts in all alloys: -H111: Applies to products that are strain-hardened less than the amount required for a controlled H11 temper. -H112: Applies to products that 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, or require mechanical property testing. The following three-digit H temper designations have been assigned for wrought prod ucts in alloys containing more than a normal 4 percent magnesium. -H311: Applies to products that are strain-hardened less than the amount required for a controlled H31 temper. -H321: Applies to products that are strain-hardened less than the amount required for a controlled H32 temper. -H323: Applies to products that are specially fabricated to have acceptable resistance to stress-corrosion cracking. -H343: Applies to products that are specially fabricated to have acceptable resistance to stress-corrosion cracking. The following three-digit -H temper designations have been assigned for Patterned or Embossed Sheet Fabricated Form -H114 -O temper -H124, -H224, -H324 -H11, -H21, -H31 temper, respectively -H134, -H234, -H334 -H12, -H22, -H32 temper, respectively -H144, -H244, -H344 -H13, -H23, -H33 temper, respectively -H154, -H254, -H354 -H14, -H24, -H34 temper, respectively -H164, -H264, -H364 -H15, -H25, -H35 temper, respectively -H174, -H274, -H374 -H16, -H26, -H36 temper, respectively -H184, -H284, -H384 -H17, -H27, -H37 temper, respectively -H194, -H294, -H394 -H18, -H28, -H38 temper, respectively -H195, -H395 -H19, -H39 temper, respectively -W, solution heat treated: An unstable temper applicable only to alloys that sponta neously age at room temperature after solution heat treatment. This designation is specific only when the period of natural aging is indicated. -T, thermally treated to produce stable tempers other than -F, -O, or -H: Applies to products that are thermally treated, with or without supplementary strain-hardening, to produce stable tempers.The -T is always followed by one or more digits. Numerals 2 through 10 have been assigned to indicate specific sequences of basic treatments, as follows: -T1, naturally aged to a substantially stable condition: Applies to products for which the rate of cooling from an elevated temperature-shaping process, such as casting or extrusion, is such that their strength is increased by room-temperature aging.
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