Aluminum 7049A-O (Annealed)
Temper
AA 7049A · EN AlZn8MgCu, AW-7049A
Interim condition only — used for severe forming or straightening before re-solution treating and ageing to a T6/T7 temper.
Values for the O condition
Other 7049A tempers and conditions
7049A is listed in 7 conditions; see the grade overview at 7049A.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Interim condition only — used for severe forming or straightening before re-solution treating and ageing to a T6/T7 temper. | 115 | 250 | 16 | 65 HB | 45 % IACS |
T73, stress relieved by stretching | Choose for plate and stretched bar that will be heavily machined and must combine SCC resistance with low distortion. | 460 | 530 | 9 | 133 HB | 40 % IACS |
Solution heat treated and overaged for stress-corrosion resistance | Use for thick forgings and fittings loaded in the short-transverse direction or exposed to salt spray, accepting ~15 % strength loss versus T6. | 465 | 535 | 9 | 135 HB | 40 % IACS |
Solution treated, mechanically stress-relieved (cold compression),… | Specified for large die forgings/hand forgings needing T73-level SCC resistance with residual stresses removed by cold compression rather than stretching. | 470 | 540 | 8 | 136 HB | 40 % IACS |
T6Default Solution heat treated and artificially aged | Pick for maximum static strength in forgings and extrusions where short-transverse sustained tensile stress and chloride exposure are controlled. | 570 | 640 | 7 | 150 HB | 37 % IACS |
Solution treated, stress-relieved by stretching, then artificially aged | Choose for straight, low-residual-stress extruded sections and rod that must hold tight machined tolerances without post-stretch straightening. | 570 | 635 | 7 | 150 HB | 37 % IACS |
T6, stress relieved by stretching, minor straightening | Standard commercial supply condition for long 7049A extrusions and drawn rod where slight straightening after stretching is allowed. | 570 | 635 | 7 | 150 HB | 37 % IACS |
What is 7049A-O?
7049A-O is 7049A in the O temper — interim condition only — used for severe forming or straightening before re-solution treating and ageing to a T6/T7 temper. 7049A-O has a yield strength of 115 MPa (16.7 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 79% of aluminum grades. Elongation at break is 16% and the elastic modulus is 71 GPa (10.3 Msi). 7049A-O has a density of 2.84 g/cm³ (0.103 lb/in³), heavier than 93% of aluminum grades. It melts at 477°C (891 °F). T6 is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- High electrical conductivity — 45 % IACS, better than 86% of aluminum grades
- Conducts heat well — 175 W/m·K (101.1 BTU/hr·ft·°F), better than 85% of aluminum grades
- Ductile — tolerates forming and impact — 16%, better than 84% of aluminum grades
- Forms and bends easily — 60/100, better than 77% of aluminum grades
Limitations
- Difficult to weld — 12/100, worse than 98% of aluminum grades
- Low strength — 115 MPa (16.7 ksi), worse than 79% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
- Needs corrosion protection — 40/100, worse than 75% of aluminum grades
7049A-O properties
Typical room-temperature values for 7049A-O; 10 are specific to this condition. Other listed values are 7049A reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
7049A-O has a density of 2.84 g/cm³ (0.103 lb/in³), heavier than 93% of aluminum grades. It melts at 477°C (891 °F).
Mechanical14
7049A-O has a yield strength of 115 MPa (16.7 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 79% of aluminum grades. Elongation at break is 16% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
7049A-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 23.4 µm/m·K (13 µin/in·°F).
Electrical3
7049A-O conducts electricity at 45 % IACS, better than 86% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 75% of aluminum grades.
Sustainability4
Producing a kilogram of 7049A-O takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 8%.
Manufacturability8
7049A-O's machinability is fair (45/100, worse than 72% of aluminum grades); weldability not recommended (12/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 7049A-O
Is 7049A easy to machine?
Machines well in T6/T73 with sharp carbide (polished flutes, high rake), 300–900 m/min and copious lubrication; deep pockets in T6 can distort, so prefer stress-relieved T6511/T7351/T7452 stock and rough-then-finish sequencing.
Can 7049A be welded?
Not arc weldable — Cu-bearing 7000-series cracks and loses SCC resistance in the HAZ; join by fasteners, adhesive bonding, or friction-stir/electron-beam with qualified procedures only.
Can 7049A be formed, bent or molded?
Hot forge/extrude at roughly 350–440 °C then solution treat (~470 °C) and quench; cold forming in T6 is impractical, so form in O temper or as-quenched W condition and age afterwards.
What surface finishes work on 7049A?
Standard finishes are chromic/sulfuric or hard anodize plus primer; chemical conversion coating (Alodine) for electrical bonding, and shot peening of machined fillets is common to offset SCC and fatigue sensitivity.
7049A 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 |
|---|---|---|
| Si | ≤ 0.4 | — |
| Fe | ≤ 0.5 | — |
| Cu | 1.2 – 1.9 | 1.5 |
| Mn | ≤ 0.5 | — |
| Mg | 2.1 – 3.1 | 2.6 |
| Cr | 0.05 – 0.25 | 0.15 |
| Zn | 7.2 – 8.4 | 7.8 |
| TiTi + Zr combined limit 0.25 max | ≤ 0.25 | — |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
7049A-O — frequently asked
What is 7049A-O used for?
7049A-O is typically used for aircraft landing gear, high-strength structural forgings and military aerospace components. In short: highest-strength 7000-series forging alloy; T73 for SCC resistance; aerospace forging grade.
What is the yield strength of 7049A-O?
7049A-O has a typical yield strength of 115 MPa (16.7 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 79% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 7049A-O easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 72% of aluminum grades). Machines well in T6/T73 with sharp carbide (polished flutes, high rake), 300–900 m/min and copious lubrication; deep pockets in T6 can distort, so prefer stress-relieved T6511/T7351/T7452 stock and rough-then-finish sequencing.
Can 7049A-O be welded?
Not readily — weldability is rated not recommended (12/100). Not arc weldable — Cu-bearing 7000-series cracks and loses SCC resistance in the HAZ; join by fasteners, adhesive bonding, or friction-stir/electron-beam with qualified procedures only.
What surface finishes work on 7049A-O?
Standard finishes are chromic/sulfuric or hard anodize plus primer; chemical conversion coating (Alodine) for electrical bonding, and shot peening of machined fillets is common to offset SCC and fatigue sensitivity.
Can 7049A-O be formed, bent or molded?
Hot forge/extrude at roughly 350–440 °C then solution treat (~470 °C) and quench; cold forming in T6 is impractical, so form in O temper or as-quenched W condition and age afterwards.
What is the maximum service temperature of 7049A-O?
7049A-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 7049A-T6 and 7049A-O?
T6 is the default condition — pick for maximum static strength in forgings and extrusions where short-transverse sustained tensile stress and chloride exposure are controlled. O: interim condition only — used for severe forming or straightening before re-solution treating and ageing to a T6/T7 temper. Yield strength is 570 MPa in T6 versus 115 MPa in O.
Sources
- EN 573-3 Aluminium and aluminium alloys — Chemical composition of wrought products — CEN (2019)
- EN 755-2 Aluminium alloy extruded rod/bar, tube and profiles — Mechanical properties — CEN (2016)
- EN 586-2 Aluminium and aluminium alloys — Forgings, mechanical properties — CEN (1994)
- 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 — ASM International (1990)
- ASM Handbook Vol. 19 — Fatigue and Fracture — ASM International (1996)
- MMPDS-17 typical property tables for 7000-series forging and extrusion alloys — Battelle/FAA (2022)
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.