Aluminium temper designations

Basic designations

F identifies an as-fabricated condition. O identifies annealed material. H identifies strain-hardened conditions. W is an unstable solution-treated condition. T identifies thermally treated conditions that produce a stable temper.

Strain-hardening families

H1 means strain hardening only; H2 adds partial annealing; H3 adds stabilization. Subsequent digits refine the condition. Do not assign an H temper to an alloy merely because the designation exists.

Thermal histories

T4 indicates solution treatment followed by natural aging. T5 indicates cooling from an elevated-temperature shaping operation followed by artificial aging. T6 indicates solution treatment and artificial aging. Detailed subdivisions require alloy and form review.

Registered and producer-specific conditions

The Aluminum Association sells a separate registered temper publication. Hydro also identifies special producer tempers that are not standard registered conditions. Preserve that distinction and confirm the intended specification.

Sources and verification

Selected facts checked 14 October 2026. Source data is reference information, not certification of supplied material.

• ESAB • Alloy and temper designation — Public article · checked 2026-10-14
• Aluminum Association • Yellow Sheets — Catalogue only; paid publication not accessed · checked 2026-10-14
• Hydro • 6061 extrusions — 2019/01 (February 2019) · checked 2026-10-14

Connect temper notation with the processing history

Speira describes cold rolling as a strengthening step and annealing as a way to obtain a forming condition. Temper designations communicate that final treatment history, but do not erase product-specific gauge or property requirements. Record the actual final condition after any forming, joining or heat treatment, because the original stock label may not describe the finished component.

Source: www.aluminum.org, www.speira.com