Aluminum 2199 T8E74
Temper · default condition
AA 2199 · UNS A92199
T8E74 = solution treated, cold worked and artificially aged
Standard supplied condition for 2199 fuselage sheet — best balance of strength, toughness and damage tolerance.
Values for the T8E74 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 |
|---|---|---|---|---|---|---|
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 |
T8E74DefaultThis page 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 T8E74?
2199 T8E74 is 2199 in the T8E74 temper — standard supplied condition for 2199 fuselage sheet — best balance of strength, toughness and damage tolerance. 2199 T8E74 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 87% of aluminum grades. Elongation at break is 11% and the elastic modulus is 78 GPa (11.3 Msi). 2199 T8E74 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).
Advantages
- Tough — resists crack growth — 40 MPa·√m (36.4 ksi·√in), better than 98% of aluminum grades
- High strength — 385 MPa (55.8 ksi), better than 87% of aluminum grades
Limitations
- Poor heat conductor — 90 W/m·K (52 BTU/hr·ft·°F), worse than 99% of aluminum grades
- Low electrical conductivity — 24 % IACS, worse than 95% of aluminum grades
- High embodied carbon — 14 kg CO₂/kg, worse than 95% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
2199 T8E74 properties
Typical room-temperature values for 2199 T8E74; 14 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 T8E74 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 T8E74 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 87% of aluminum grades. Elongation at break is 11% and the elastic modulus is 78 GPa (11.3 Msi).
Thermal6
2199 T8E74 is rated for continuous service to 120°C (248 °F). It conducts heat at 90 W/m·K (52 BTU/hr·ft·°F), worse than 99% of aluminum grades. Thermal expansion is 22.3 µm/m·K (12.4 µin/in·°F).
Electrical3
2199 T8E74 conducts electricity at 24 % IACS, worse than 95% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 69% of aluminum grades.
Sustainability4
Producing a kilogram of 2199 T8E74 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 T8E74's machinability is good (55/100, worse than 59% of aluminum grades); weldability poor (30/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 2199 T8E74
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 T8E74 — frequently asked
What is 2199 T8E74 used for?
2199 T8E74 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 T8E74?
2199 T8E74 has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 87% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is 2199 T8E74 easy to machine?
Reasonably — machinability is rated good (55/100, worse than 59% 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 T8E74 be welded?
Not readily — weldability is rated poor (30/100). 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 T8E74?
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 T8E74 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 T8E74?
2199 T8E74 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.