Tempers for Non-Heat Treatable Alloys

This guide breaks down the tempering processes for non-heat-treatable aluminum alloys, highlighting the significance of the "H" series tempers and how they enhance the mechanical properties of these materials.

The initial strength of alloys in this group depends upon the hardening effects of elements such as manganese, silicon, iron, and magnesium, singly or in various combinations. Therefore, the non-heat-treatable alloys are usually designated in the 1000, 3000, 4000, or 5000 series. Since these alloys are work-hardenable, further strengthening is made possible by various degrees of cold working, denoted by the "H" series of tempers.

H1 - strain-hardened only. This applies to products that are cold-worked to obtain the desired strength without supplementary thermal treatment. The number following this designation indicates the degree of strain-hardening.

H2 - strain-hardened and partially annealed. This applies to products that are strain-hardened more than the desired final amount and then reduced in strength to the desired level by partial annealing.

H3 - strain-hardened and stabilized. This applies to products that are strain-hardened and whose mechanical properties are stabilized by a low-temperature thermal treatment, which results in slightly lower tensile strength and improved ductibility.