Filter —
| Designation (EN AW) | Series | Temper | Rm (MPa) | Rp0.2 (MPa) | A5 (%) | HB | Machinability | Weldability | Typical applications |
|---|
Notes & design guidelines
Temper designation system
| O | Annealed — lowest strength, highest ductility |
| H1x | Strain hardened only (H12 = ¼ hard, H14 = ½ hard, H18 = full hard) |
| H3x | Strain hardened + stabilised (5xxx series) |
| T4 | Solution treated + naturally aged (room temp.) |
| T6 | Solution treated + artificially aged (peak strength) |
| T651 | T6 + stress relieved by stretching |
| T73 | Over-aged — lower strength, better SCC resistance (7xxx) |
| T3 | Solution treated + cold worked + naturally aged (2xxx) |
1xxx — Commercially pure aluminium
≥ 99 % Al. Excellent corrosion resistance and electrical conductivity. Very low strength — not suitable for structural loads. Excellent formability and weldability. Used in foil, capacitors, chemical vessels and electrical conductors.
2xxx — Al-Cu (heat treatable)
High strength after heat treatment (T3/T4/T6). Poor weldability — susceptible to hot cracking and intergranular corrosion in the heat-affected zone. Typically protected by anodising or cladding. Workhorse of aerospace structures (2024, 2017A).
5xxx — Al-Mg (non-heat-treatable)
Strengthened by cold working (H-tempers). Excellent corrosion resistance in marine environments. Good weldability — the preferred series for welded structures, shipbuilding and cryogenic tanks. Prone to work hardening during machining.
6xxx — Al-Mg-Si (heat treatable)
The engineering workhorse. Good strength, excellent extrudability, anodising response and machinability. 6082-T6 is the most common structural aluminium in Europe; 6061-T6 dominates in North America. Both are CNC machining standards.
7xxx — Al-Zn (heat treatable)
Highest strength of all aluminium alloys. Susceptible to stress corrosion cracking (SCC) — T73/T7351 tempers trade some strength for better SCC resistance. Practically not weldable by conventional methods. Used in aerospace primary structures, high-performance sports equipment and tooling plates.