Aluminum 7076-O (Annealed)
Temper
AA 7076 · UNS A97076
Choose for severe cold forming or straightening before solution treating and ageing to T6/T61.
Values for the O condition
Other 7076 tempers and conditions
7076 is listed in 4 conditions; see the grade overview at 7076.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Choose for severe cold forming or straightening before solution treating and ageing to T6/T61. | 105 | 230 | 17 | 60 HB | 40 % IACS |
As fabricated | Mill/forge delivery condition for stock that will be solution treated and aged by the customer. | 180 | 300 | 12 | 85 HB | 40 % IACS |
Solution heat treated and artificially aged | Standard peak-strength condition for extrusions and machined parts where SCC exposure is limited. | 435 | 500 | 11 | 140 HB | 32 % IACS |
T61Default T6 variant, underaged | The historically standard supply condition for 7076 forgings and propeller blades — full strength with slightly improved toughness/consistency over plain T6. | 448 | 510 | 12 | 142 HB | 33 % IACS |
What is 7076-O?
7076-O is 7076 in the O temper — choose for severe cold forming or straightening before solution treating and ageing to T6/T61. 7076-O has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 230 MPa (33.4 ksi) — weaker than 84% of aluminum grades. Elongation at break is 17% and the elastic modulus is 71 GPa (10.3 Msi). 7076-O has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 475°C (887 °F). T61 is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 17%, better than 85% of aluminum grades
- Conducts heat well — 175 W/m·K (101.1 BTU/hr·ft·°F), better than 85% of aluminum grades
- Forms and bends easily — 70/100, better than 83% of aluminum grades
Limitations
- Difficult to weld — 20/100, worse than 89% of aluminum grades
- Low strength — 105 MPa (15.2 ksi), worse than 84% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
7076-O properties
Typical room-temperature values for 7076-O; 11 are specific to this condition. Other listed values are 7076 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
7076-O has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 475°C (887 °F).
Mechanical12
7076-O has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 230 MPa (33.4 ksi) — weaker than 84% of aluminum grades. Elongation at break is 17% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
7076-O is rated for continuous service to 120°C (248 °F). It conducts heat at 175 W/m·K (101.1 BTU/hr·ft·°F), better than 85% of aluminum grades. Thermal expansion is 23.6 µm/m·K (13.1 µin/in·°F).
Electrical3
7076-O conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 7076-O takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 20%.
Manufacturability7
7076-O's machinability is fair (45/100, worse than 72% of aluminum grades); weldability poor (20/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 7076-O
Is 7076 easy to machine?
Machines freely in T6/T61 with sharp carbide tooling, high speeds and generous coolant; produces clean chips but leaves high residual stress that can distort thin parts.
Can 7076 be welded?
Not recommended for arc welding (hot cracking and severe HAZ SCC due to Zn+Cu); join by riveting, bolting or friction-stir/adhesive methods.
Can 7076 be formed, bent or molded?
Hot forge/extrude at roughly 380–440 °C; do cold forming in the O or freshly quenched W temper, then age — T61 material has little cold formability.
What surface finishes work on 7076?
Takes clear and hard anodizing well (slightly grey tone), chromate/trivalent conversion coating and primer-paint systems; shot peening plus a protective coating is advisable where stress-corrosion exposure is possible.
7076 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Siimpurity limit | ≤ 0.4 | — |
| Feimpurity limit | ≤ 0.6 | — |
| Cu | 0.3 – 1 | 0.6 |
| Mngrain-structure control in place of Cr | 0.3 – 0.8 | 0.55 |
| Mg | 1.2 – 2 | 1.6 |
| Znprincipal strengthening addition | 7 – 8 | 7.5 |
| Tigrain refiner | ≤ 0.2 | — |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
7076-O — frequently asked
What is 7076-O used for?
7076-O is typically used for structural extrusions, legacy aerospace components, replacement forgings for older airframes, machined structural fittings, bolted frame and beam sections and repair and MRO spares. In short: legacy 7075 substitute; high-strength extrusion alloy; limited current availability.
What is the yield strength of 7076-O?
7076-O has a typical yield strength of 105 MPa (15.2 ksi) and a tensile strength of 230 MPa (33.4 ksi) — weaker than 84% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is 7076-O easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 72% of aluminum grades). Machines freely in T6/T61 with sharp carbide tooling, high speeds and generous coolant; produces clean chips but leaves high residual stress that can distort thin parts.
Can 7076-O be welded?
Not readily — weldability is rated poor (20/100). Not recommended for arc welding (hot cracking and severe HAZ SCC due to Zn+Cu); join by riveting, bolting or friction-stir/adhesive methods.
What surface finishes work on 7076-O?
Takes clear and hard anodizing well (slightly grey tone), chromate/trivalent conversion coating and primer-paint systems; shot peening plus a protective coating is advisable where stress-corrosion exposure is possible.
Can 7076-O be formed, bent or molded?
Hot forge/extrude at roughly 380–440 °C; do cold forming in the O or freshly quenched W temper, then age — T61 material has little cold formability.
What is the maximum service temperature of 7076-O?
7076-O is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 7076-T61 and 7076-O?
T61 is the default condition — the historically standard supply condition for 7076 forgings and propeller blades — full strength with slightly improved toughness/consistency over plain T6. O: choose for severe cold forming or straightening before solution treating and ageing to T6/T61. Yield strength is 448 MPa in T61 versus 105 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol.5 — Surface Engineering; Vol.6 — Welding, Brazing and Soldering; Vol.13 — Corrosion — ASM International (1994)
- MMPDS-style typical property tables for 7000-series wrought alloys — Battelle/FAA (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.