Aluminum Temper Guide

The supplier's listings publish temper codes across the O, H and T families, plus F as fabricated. A temper tells you how the metal got its mechanical properties: by annealing (O), by cold work (H), by heat treatment (T), or as fabricated with no special control (F). Two coils of identical alloy and thickness in different tempers are different products, and a quotation that does not state the temper is not yet a specification.

O — annealed

O is the softest, fully annealed condition: maximum formability, minimum strength. The coil-strip grade listings write it as 'HO' alongside the H ranges (for example 'Temper: HO, H12–H26'), and the electrical 1350 listing specifies temper O for transformer strip — the application explains the choice, since winding strip must form tightly without cracking. Order O when the part will be deep drawn, spun, or wound, and when a later heat treatment or the forming itself supplies the working properties.

H — strain hardened (1xxx, 3xxx, 5xxx, 8xxx)

H tempers apply to non-heat-treatable alloys, whose strength comes from rolling work. The first digit after H describes the route: H1 is strain hardened only, H2 is strain hardened then partially annealed back, H3 is strain hardened and stabilised (the route used for magnesium-bearing 5xxx alloys, hence 5052's H32/H34/H38). The second digit is the hardness level on a scale where 2 is quarter-hard, 4 is half-hard, 6 is three-quarter hard and 8 is full hard. Reading the catalogue with that key: the grade coil listings' H12–H26 ranges are the 1xxx/3xxx ladder from soft H12 to hard H26; 5052's H32/H34/H38 are the stabilised equivalents; the 8011 strip listing's H0, H14, H16, H18 and H24 set spans annealed to full hard for foil-family strip.

H111, H112, H114 — the special cases in the 5052 listing

Three H codes in the 5052 listing deserve their own lines. H111 is strain hardened a small, incidental amount during processes such as levelling — near-O softness with a defined temper. H112 is the condition acquired from shaping at elevated temperature or a limited amount of cold work, used for plate products. H114 is a defined strain-hardened temper for specific sheet products. In practice: for formable 5052 sheet, buyers specify from the H111/H32 end; for plate, H112 and the O condition are the common quotation bases. That is the set the 5052 listing itself publishes; the exact temper for an order is confirmed in the quotation.

T — heat treated (2xxx, 6xxx, 7xxx families)

T tempers belong to heat-treatable alloys. T4 is solution heat treated and naturally aged — formable for a T temper, and the condition in which some plate is supplied for later ageing. T6 is solution heat treated and artificially aged to near-maximum strength — the standard condition for 6061 machined and structural parts in this catalogue. T451 and T651 add stress relief by stretching to the T4 and T6 routes respectively (the '51' suffix): the stretched versions — T651 above all — are the plate conditions specified when machining must not release internal stress and move the part. Where this catalogue's listings publish T tempers, they are quoted with the product; where a listing is silent, the temper is a quotation item — name the code you need when you enquire.

F — as fabricated

F means no special control over thermal or strain-hardened condition — the properties are whatever the fabrication route produced. It appears in plate and profile contexts where the buyer machines the metal heavily or re-processes it, and it should never be read as a property promise. If a drawing states F, the enquiry conversation confirms what condition will actually be delivered; if a drawing states nothing, that gap — not the alloy — is the first thing to close.

The working rule across this catalogue: alloy chooses the family, temper chooses the behaviour. When you send an enquiry, the temper is not a detail to add later — state it with the alloy and thickness, and where you are unsure which temper your process needs, describe the process (bending radius, draw depth, machining, welding) and let the quotation propose from the published temper sets on the grade pages.