Aluminum 2199-O (Annealed)
Temper
AA 2199 · UNS A92199
Softest condition for deep forming or intermediate processing before re-solution treatment.
Values for the O condition
Other 2199 tempers and conditions
2199 is listed in 6 conditions; see the grade overview at 2199.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Softest condition for deep forming or intermediate processing before re-solution treatment. | 135 | 250 | 20 | 65 HB | 33 % IACS |
T3, stress relieved by stretching | Plate condition with low residual stress for stable heavy machining before final ageing. | 265 | 395 | 17 | 108 HB | 21 % IACS |
Solution heat treated, cold worked and naturally aged | Naturally aged sheet used when parts must be formed or stretch-formed before final artificial ageing. | 270 | 400 | 18 | 110 HB | 21 % IACS |
T8E74Default Solution treated, cold worked and artificially aged | Standard supplied condition for 2199 fuselage sheet — best balance of strength, toughness and damage tolerance. | 385 | 450 | 11 | 130 HB | 24 % IACS |
T8, stress relieved by stretching | Low-residual-stress plate temper for machined lower-wing panels and frames. | 420 | 470 | 9 | 136 HB | 24 % IACS |
Solution treated, cold worked ~6 % and artificially aged | Highest-strength condition for extrusions and stringers where toughness demand is lower. | 455 | 490 | 8 | 142 HB | 25 % IACS |
What is 2199-O?
2199-O is 2199 in the O temper — softest condition for deep forming or intermediate processing before re-solution treatment. 2199-O has a yield strength of 135 MPa (19.6 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 72% of aluminum grades. Elongation at break is 20% and the elastic modulus is 78 GPa (11.3 Msi). 2199-O has a density of 2.63 g/cm³ (0.095 lb/in³), lighter than 95% of aluminum grades. It melts at 545°C (1,013 °F). T8E74 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
- Forms and bends easily — 75/100, better than 86% of aluminum grades
Limitations
- High embodied carbon — 14 kg CO₂/kg, worse than 95% of aluminum grades
- Difficult to machine — 40/100, worse than 81% of aluminum grades
- Poor heat conductor — 120 W/m·K (69.3 BTU/hr·ft·°F), worse than 80% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
2199-O properties
Typical room-temperature values for 2199-O; 19 are specific to this condition. Other listed values are 2199 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
2199-O has a density of 2.63 g/cm³ (0.095 lb/in³), lighter than 95% of aluminum grades. It melts at 545°C (1,013 °F).
Mechanical12
2199-O has a yield strength of 135 MPa (19.6 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 72% of aluminum grades. Elongation at break is 20% and the elastic modulus is 78 GPa (11.3 Msi).
Thermal6
2199-O is rated for continuous service to 120°C (248 °F). It conducts heat at 120 W/m·K (69.3 BTU/hr·ft·°F), worse than 80% of aluminum grades. Thermal expansion is 22.3 µm/m·K (12.4 µin/in·°F).
Electrical3
2199-O conducts electricity at 33 % IACS, worse than 57% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 2199-O takes about 230 MJ of energy and emits 14 kg of CO₂ — more than 96% of aluminum grades. Typical recycled content is 5%.
Manufacturability8
2199-O's machinability is fair (40/100, worse than 81% of aluminum grades); weldability fair (35/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 2199-O
Is 2199 easy to machine?
Machines like 2024-T8 with sharp PCD/carbide tooling and flood coolant; fine Al-Li chips and dust are reactive, so keep swarf dry, segregated and away from water or acid.
Can 2199 be welded?
Fusion welding is hot-crack and porosity prone; friction stir welding, laser-beam welding with dedicated Al-Li filler, or riveting/bonding are the accepted joining routes.
Can 2199 be formed, bent or molded?
Form in O or T3 temper then age to T8; the T8 condition has limited stretch and pronounced planar anisotropy, so bend radii and blank orientation must be controlled.
What surface finishes work on 2199?
Chromic or thin-film sulfuric anodize plus chromate-free primer is standard; alkaline etch times must be shortened because Li-bearing surfaces attack faster than 2024.
2199 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 |
|---|---|---|
| Liprimary density-reducing, modulus-raising addition | 1.4 – 1.8 | 1.6 |
| Cu | 2.3 – 2.9 | 2.6 |
| Znimproves corrosion behaviour | 0.2 – 0.9 | 0.6 |
| Mn | 0.1 – 0.5 | 0.3 |
| Mg | 0.05 – 0.4 | 0.2 |
| Zrgrain-structure control (Al3Zr dispersoids) | 0.05 – 0.12 | 0.09 |
| Ti | ≤ 0.1 | — |
| Feimpurity limit for toughness | ≤ 0.07 | — |
| Siimpurity limit for toughness | ≤ 0.05 | — |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
2199-O — frequently asked
What is 2199-O used for?
2199-O is typically used for fuselage sheet, aerospace skins, lower wing skin panels, damage-tolerant plate for frames, bonded and riveted skin assemblies and pressure cabin structure. In short: tougher companion to 2198; lithium-based weight reduction; damage-tolerant skin alloy.
What is the yield strength of 2199-O?
2199-O has a typical yield strength of 135 MPa (19.6 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 72% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is 2199-O easy to machine?
Not especially — machinability is rated fair (40/100, worse than 81% of aluminum grades). Machines like 2024-T8 with sharp PCD/carbide tooling and flood coolant; fine Al-Li chips and dust are reactive, so keep swarf dry, segregated and away from water or acid.
Can 2199-O be welded?
With care — weldability is rated fair (35/100). Fusion welding is hot-crack and porosity prone; friction stir welding, laser-beam welding with dedicated Al-Li filler, or riveting/bonding are the accepted joining routes.
What surface finishes work on 2199-O?
Chromic or thin-film sulfuric anodize plus chromate-free primer is standard; alkaline etch times must be shortened because Li-bearing surfaces attack faster than 2024.
Can 2199-O be formed, bent or molded?
Form in O or T3 temper then age to T8; the T8 condition has limited stretch and pronounced planar anisotropy, so bend radii and blank orientation must be controlled.
What is the maximum service temperature of 2199-O?
2199-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 2199 T8E74 and 2199-O?
T8E74 is the default condition — standard supplied condition for 2199 fuselage sheet — best balance of strength, toughness and damage tolerance. O: softest condition for deep forming or intermediate processing before re-solution treatment. Yield strength is 385 MPa in T8E74 versus 135 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- Alcoa third-generation Al-Li alloy product information (2199/2099/2060 family) — Alcoa / Arconic (2016)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Aluminum-Lithium Alloys: Processing, Properties and Applications — Elsevier / Butterworth-Heinemann (2014)
- MMPDS-style typical property compilations for aerospace aluminium — Battelle (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.