Aluminum 2027-O (Annealed)
Temper
AA 2027 · UNS A92027
Softest condition for deep forming or heavy machining before solution heat treatment.
Values for the O condition
Other 2027 tempers and conditions
2027 is listed in 7 conditions; see the grade overview at 2027.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Softest condition for deep forming or heavy machining before solution heat treatment. | 100 | 220 | 20 | 50 HB | 47 % IACS |
As fabricated | Mill stock intended for further heat treatment; no mechanical property guarantees. | 160 | 280 | 16 | 75 HB | 40 % IACS |
Solution heat treated and naturally aged | Used when parts are formed after solution treatment and no stretch relief is applied. | 300 | 450 | 18 | 122 HB | 30 % IACS |
Solution heat treated, cold worked and naturally aged | Sheet/thin-plate damage-tolerant condition where the cold work is not a controlled stretch. | 335 | 470 | 16 | 130 HB | 30 % IACS |
T351Default T3, stress relieved by stretching | Standard damage-tolerant plate temper for fuselage panels and lower wing skins — best toughness/FCG combination. | 340 | 475 | 15 | 132 HB | 30 % IACS |
Solution heat treated, stretched, minor straightening, naturally aged | Extruded stringer/frame condition where residual stress must be low and shape tolerance tight. | 365 | 490 | 13 | 138 HB | 30 % IACS |
T8, stress relieved by stretching | Pick when higher yield strength, better thermal stability and improved intergranular corrosion resistance are needed at some cost in toughness. | 425 | 490 | 8 | 142 HB | 38 % IACS |
What is 2027-O?
2027-O is 2027 in the O temper — softest condition for deep forming or heavy machining before solution heat treatment. 2027-O has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 84% of aluminum grades. Elongation at break is 20% and the elastic modulus is 73 GPa (10.6 Msi). 2027-O has a density of 2.77 g/cm³ (0.1 lb/in³), heavier than 71% of aluminum grades. It melts at 502°C (936 °F). T351 is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 40 MPa·√m (36.4 ksi·√in), better than 98% of aluminum grades
- Ductile — tolerates forming and impact — 20%, better than 89% of aluminum grades
- Conducts heat well — 190 W/m·K (109.8 BTU/hr·ft·°F), better than 89% of aluminum grades
- Forms and bends easily — 80/100, better than 89% of aluminum grades
- High electrical conductivity — 47 % IACS, better than 88% of aluminum grades
Limitations
- Needs corrosion protection — 33/100, worse than 91% of aluminum grades
- Difficult to weld — 20/100, worse than 89% of aluminum grades
- Low strength — 100 MPa (14.5 ksi), worse than 84% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
2027-O properties
Typical room-temperature values for 2027-O; 10 are specific to this condition. Other listed values are 2027 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
2027-O has a density of 2.77 g/cm³ (0.1 lb/in³), heavier than 71% of aluminum grades. It melts at 502°C (936 °F).
Mechanical13
2027-O has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 84% of aluminum grades. Elongation at break is 20% and the elastic modulus is 73 GPa (10.6 Msi).
Thermal6
2027-O is rated for continuous service to 120°C (248 °F). It conducts heat at 190 W/m·K (109.8 BTU/hr·ft·°F), better than 89% of aluminum grades. Thermal expansion is 22.9 µm/m·K (12.7 µin/in·°F).
Electrical3
2027-O conducts electricity at 47 % IACS, better than 88% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (33/100), worse than 91% of aluminum grades.
Sustainability4
Producing a kilogram of 2027-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%.
Manufacturability7
2027-O's machinability is fair (45/100, worse than 72% of aluminum grades); weldability poor (20/100); formability very good (80/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 2027-O
Is 2027 easy to machine?
Machines well in T351/T851 with sharp carbide tooling, high speed and flood coolant; long chips need chipbreakers, and residual-stress-driven distortion is minimized by using stretched (T3x1/T8x1) plate.
Can 2027 be welded?
Not recommended for fusion (arc) welding due to hot cracking; join by riveting, bolting, adhesive bonding or friction stir welding with post-weld corrosion protection.
Can 2027 be formed, bent or molded?
Form in O or freshly solution-treated (T4/W) condition, ideally within a few hours or after refrigeration; T351 plate tolerates only mild bending with generous radii.
What surface finishes work on 2027?
Alkaline clean + chromate/chromate-free conversion coating or chromic/sulfuric anodize plus primer for service; avoid bare exposure in marine or chloride environments.
2027 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 |
|---|---|---|
| Silow-impurity, damage-tolerant chemistry | ≤ 0.12 | 0.05 |
| Ferestricted to limit coarse constituent particles | ≤ 0.15 | 0.07 |
| Cu | 3.9 – 4.6 | 4.2 |
| Mn | 0.5 – 1 | 0.7 |
| Mg | 1 – 1.5 | 1.25 |
| Cr | ≤ 0.05 | — |
| Zn | ≤ 0.25 | — |
| Zrdispersoid former for grain-structure control | 0.05 – 0.15 | 0.1 |
| Ti | ≤ 0.08 | 0.03 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
2027-O — frequently asked
What is 2027-O used for?
2027-O is typically used for aircraft fuselage plate, wing structural members and ribs, machined bulkheads and frames, fatigue-critical fittings from thick plate, wing skin and stringer stock and floor beams and seat-track supports. In short: fatigue-tuned 2024 alternative; damage-tolerant fuselage plate; good-machining aerospace 2000 series.
What is the yield strength of 2027-O?
2027-O has a typical yield strength of 100 MPa (14.5 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 84% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 2027-O easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 72% of aluminum grades). Machines well in T351/T851 with sharp carbide tooling, high speed and flood coolant; long chips need chipbreakers, and residual-stress-driven distortion is minimized by using stretched (T3x1/T8x1) plate.
Can 2027-O be welded?
Not readily — weldability is rated poor (20/100). Not recommended for fusion (arc) welding due to hot cracking; join by riveting, bolting, adhesive bonding or friction stir welding with post-weld corrosion protection.
What surface finishes work on 2027-O?
Alkaline clean + chromate/chromate-free conversion coating or chromic/sulfuric anodize plus primer for service; avoid bare exposure in marine or chloride environments.
Can 2027-O be formed, bent or molded?
Form in O or freshly solution-treated (T4/W) condition, ideally within a few hours or after refrigeration; T351 plate tolerates only mild bending with generous radii.
What is the maximum service temperature of 2027-O?
2027-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 2027-T351 and 2027-O?
T351 is the default condition — standard damage-tolerant plate temper for fuselage panels and lower wing skins — best toughness/FCG combination. O: softest condition for deep forming or heavy machining before solution heat treatment. Yield strength is 340 MPa in T351 versus 100 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 — ASM International (1990)
- MMPDS-17 Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
- Damage-tolerant 2000-series aerospace plate and extrusion product data — Alcoa/Arconic; Constellium (2020)
- ASM Handbook Vol. 13B: Corrosion — Materials — ASM International (2005)
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.