Aluminum 7136-O (Annealed)
Temper
AA 7136 · UNS A97136
Softest condition, supplied only for further forming or re-heat-treatment; not a structural condition.
Values for the O condition
Other 7136 tempers and conditions
7136 is listed in 6 conditions; see the grade overview at 7136.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Softest condition, supplied only for further forming or re-heat-treatment; not a structural condition. | 110 | 235 | 16 | 62 HB | 45 % IACS |
Solution heat treated, stress relieved by stretching | Transient as-quenched condition used for forming or straightening before artificial ageing; properties change with time. | 250 | 400 | 16 | 92 HB | 30 % IACS |
Solution treated, stretched, fully over-aged | Choose when maximum stress-corrosion-cracking immunity and toughness are needed, accepting ~8 % lower strength. | 585 | 620 | 12 | 165 HB | 40 % IACS |
Solution treated, stretched, over-aged between T73 and T76 | Balanced temper for thick extrusions and forged-like sections needing good short-transverse SCC performance with near-T76 strength. | 605 | 640 | 11 | 170 HB | 38 % IACS |
T76511Default Solution treated, stretched, over-aged for exfoliation resistance | Standard aerospace supply condition for 7136 extrusions — near-peak strength with EXCO-rated exfoliation resistance and improved toughness. | 620 | 655 | 11 | 175 HB | 36 % IACS |
T6, stress relieved by stretching, minor straightening | Highest strength condition of 7136 extrusions; use only where SCC exposure and thick-section toughness are not critical. | 670 | 700 | 9 | 190 HB | 31 % IACS |
What is 7136-O?
7136-O is 7136 in the O temper — softest condition, supplied only for further forming or re-heat-treatment; not a structural condition. 7136-O has a yield strength of 110 MPa (16 ksi) and a tensile strength of 235 MPa (34.1 ksi) — weaker than 81% of aluminum grades. Elongation at break is 16% and the elastic modulus is 71 GPa (10.3 Msi). 7136-O has a density of 2.85 g/cm³ (0.103 lb/in³), heavier than 96% of aluminum grades. It melts at 477°C (891 °F). T76511 is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 60 MPa·√m (54.6 ksi·√in), better than 100% of aluminum grades
- 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 — 65/100, better than 80% of aluminum grades
Limitations
- Difficult to weld — 16/100, worse than 95% of aluminum grades
- Low strength — 110 MPa (16 ksi), worse than 81% of aluminum grades
7136-O properties
Typical room-temperature values for 7136-O; 22 are specific to this condition. Other listed values are 7136 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
7136-O has a density of 2.85 g/cm³ (0.103 lb/in³), heavier than 96% of aluminum grades. It melts at 477°C (891 °F).
Mechanical14
7136-O has a yield strength of 110 MPa (16 ksi) and a tensile strength of 235 MPa (34.1 ksi) — weaker than 81% of aluminum grades. Elongation at break is 16% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
7136-O is rated for continuous service to 150°C (302 °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
7136-O conducts electricity at 45 % IACS, better than 86% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 55% of aluminum grades.
Sustainability4
Producing a kilogram of 7136-O takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 10%.
Manufacturability7
7136-O's machinability is fair (45/100, worse than 72% of aluminum grades); weldability poor (16/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 7136-O
Is 7136 easy to machine?
Machines very well in T7x tempers with sharp polished carbide tools, high speed and flood/MQL coolant; produces short chips but requires care with residual-stress distortion on thin machined pockets.
Can 7136 be welded?
Not suitable for fusion welding (Cu-bearing 7000-series hot-cracks and loses HAZ strength) — join by fasteners, adhesive bonding or friction stir welding with post-weld ageing evaluation.
Can 7136 be formed, bent or molded?
Extruded to shape at 380–440 °C; cold forming in T7x is limited to large-radius bends, do severe forming in W or O temper and re-age.
What surface finishes work on 7136?
Chromic or sulfuric anodize, hard anodize, chromate/trivalent conversion coat and epoxy primer are standard; avoid alkaline etch overexposure and use cadmium-free coated fasteners to limit galvanic attack.
7136 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 |
|---|---|---|
| Znprincipal strengthening element | 8.4 – 9.4 | 8.9 |
| Mg | 1.8 – 2.5 | 2.2 |
| Cu | 1.9 – 2.5 | 2.2 |
| ZrAl3Zr dispersoids control recrystallisation | 0.1 – 0.2 | 0.15 |
| Feimpurity limit | ≤ 0.15 | — |
| Siimpurity limit | ≤ 0.12 | — |
| Mn | ≤ 0.05 | — |
| Cr | ≤ 0.05 | — |
| Ti | ≤ 0.1 | — |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
7136-O — frequently asked
What is 7136-O used for?
7136-O is typically used for aircraft fuselage skins, lower wing skins and structural aerospace sheet. In short: improved strength/toughness 7000 series; aerospace extrusion alloy; fasteners or FSW only.
What is the yield strength of 7136-O?
7136-O has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 235 MPa (34.1 ksi) — weaker than 81% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is 7136-O easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 72% of aluminum grades). Machines very well in T7x tempers with sharp polished carbide tools, high speed and flood/MQL coolant; produces short chips but requires care with residual-stress distortion on thin machined pockets.
Can 7136-O be welded?
Not readily — weldability is rated poor (16/100). Not suitable for fusion welding (Cu-bearing 7000-series hot-cracks and loses HAZ strength) — join by fasteners, adhesive bonding or friction stir welding with post-weld ageing evaluation.
What surface finishes work on 7136-O?
Chromic or sulfuric anodize, hard anodize, chromate/trivalent conversion coat and epoxy primer are standard; avoid alkaline etch overexposure and use cadmium-free coated fasteners to limit galvanic attack.
Can 7136-O be formed, bent or molded?
Extruded to shape at 380–440 °C; cold forming in T7x is limited to large-radius bends, do severe forming in W or O temper and re-age.
What is the maximum service temperature of 7136-O?
7136-O is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 7136 T76511 and 7136-O?
T76511 is the default condition — standard aerospace supply condition for 7136 extrusions — near-peak strength with EXCO-rated exfoliation resistance and improved toughness. O: softest condition, supplied only for further forming or re-heat-treatment; not a structural condition. Yield strength is 620 MPa in T76511 versus 110 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)
- MMPDS-17 Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
- High-strength 7000-series aerospace extrusion alloy data (7136/7055/7150 class) — Universal Alloy Corporation / Alcoa (2015)
- ASTM B221 — Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes — ASTM International (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.