H1strain-hardened only. Applies to products which are strain-hardened or cold worked to obtain the desired strength level without supplementary thermal treatments. The number following this designation indicates the degree of strain-hardening.
H2strain-hardened and partially annealed. Applies to products strain-hardened or cold worked more than the desired final amount and then reduced in strength to that desired level by partial annealing. The number following this designation indicates the degree of strain-hardening remaining after the partial annealing operation.
H3 strain-hardened and stabilized. Applies to products in the magnesium-aluminum class which will age-soften at room temperature after strain-hardening. These products are strain-hardened to the desired amount and then subjected to a low temperature thermal operation which results in a stable but slightly lower tensile strength and improved ductility. The number following this designation indicates the degree of strain-hardening remaining after the stabilization treatment.
The digit following the designation H1, H2 or H3 indicates the degree of strain-hardening as follows:
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H-1 1/8 hard |
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H-2 1/4 hard |
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H-3 3/8 hard |
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H-4 1/2 hard |
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H-5 5/8 hard |
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H-6 3/4 hard |
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H-7 7/8 hard |
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H-8 full hard (approximately 75% reduction after
a full anneal) |
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H-9 extra hard (limited to certain alloys and/or
product forms) |
The third digit, when used, indicates a variation of the two digit temper. It is used when the degree of control of temper or the mechanical properties are different from but close to the two-digit designation to which it is added, or when some other characteristic is significantly affected.
The following three-digit H temper designations have been assigned for wrought products in all alloys:
H-11 Applies to products which incur sufficient strain- hardening after the final anneal that they fail to qualify as annealed but not enough to qualify as H-1.
H112 Applies to products which may acquire some temper from working at an elevated temperature and for which there are mechanical property limits.
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