T3
Solution treated, cold worked, naturally aged. Standard for sheet; best fatigue and crack-growth behaviour.
Aircraft sheet & plate · 2xxx series
2024 (2A12) Aircraft Aluminium Sheet & Plate
2024-T3 sheet is the classic fuselage-skin material: high strength, excellent fatigue performance and slow crack growth, usually supplied as Alclad for corrosion protection. 2024-T351 plate is machined into frames, spars and fittings. Metline supplies bare and Alclad 2024 sheet and plate, and the close equivalent 2A12, in O, T3, T4, T351, T81 and T851, certified to AMS, ASTM and EN standards, to customers worldwide.
- Alloy
- 2024 / 2A12
- Tempers
- O, T3, T4, T351, T81, T851
- Thickness
- 0.3 – 150 mm
- Standards
- AMS 4037 · QQ-A-250/4 · ASTM B209
Why 2024 sheet and plate is used on aircraft
Pressurised fuselages and lower wing skins are loaded in tension and cycled on every flight. The governing properties are fatigue strength, fracture toughness and resistance to fatigue crack growth, and 2024-T3 has been the reference material for those properties since the 1930s.
Sheet (up to about 6 mm) is normally supplied in T3: solution treated, cold worked by flattening and stretching, and naturally aged. Much of it is Alclad 2024, which carries a thin layer of high-purity 1230 aluminium on each face, typically about 5 % of thickness per side for sheet under 1.6 mm and 2.5 % per side for thicker material. The cladding corrodes sacrificially, so scratches and rivet holes do not expose the core to attack.
Plate (over about 6 mm) is supplied in T351, stretched to relieve quench stresses so it stays flat when machined into frames, spars, ribs and bulkheads. Where higher yield strength or better stress-corrosion resistance is needed, T851 plate (artificially aged) is used, and for the most demanding damage-tolerant applications the higher-purity derivatives 2124-T851 and 2524-T3 are specified.
2024 and 2A12 composition (wt %)
| Element | 2024 (AA / ASTM, EN AW-2024) | 2A12 (GB, close equivalent) | Role |
|---|---|---|---|
| Copper (Cu) | 3.8 – 4.9 | 3.8 – 4.9 | Main strengthening element |
| Magnesium (Mg) | 1.2 – 1.8 | 1.2 – 1.8 | With Cu forms the Al2CuMg (S-phase) precipitates |
| Manganese (Mn) | 0.30 – 0.9 | 0.30 – 0.9 | Grain control, toughness |
| Silicon (Si) | 0.50 max | 0.50 max | Impurity |
| Iron (Fe) | 0.50 max | 0.50 max | Impurity; low Fe improves toughness |
| Chromium (Cr) | 0.10 max | — | Impurity |
| Nickel (Ni) | — | 0.10 max | Impurity |
| Zinc (Zn) | 0.25 max | 0.30 max | Impurity |
| Titanium (Ti) | 0.15 max | 0.15 max | Grain refiner |
| Others, each / total | 0.05 / 0.15 | 0.05 / 0.10 | |
| Aluminium (Al) | Remainder | Remainder | About 90.7 – 94.7 % |
Alclad 2024 has a 2024 core with 1230 cladding (99.30 % Al minimum). The certificate reports core chemistry and, on request, cladding thickness.
Mechanical properties by temper
Typical values first, then specified minimums from EN 485-2 for bare material. ASTM B209 minimums are very similar (for example 2024-T3 sheet 1.6 – 3.2 mm: 434 MPa tensile, 290 MPa yield). Alclad minimums are a few per cent lower because the soft cladding carries little load.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation | Brinell hardness | Shear strength |
|---|---|---|---|---|---|
| O | 186 MPa / 27 ksi | 76 MPa / 11 ksi | 20 % | 47 HB | 125 MPa |
| T3 | 483 MPa / 70 ksi | 345 MPa / 50 ksi | 18 % | 120 HB | 283 MPa |
| T4, T351 | 469 MPa / 68 ksi | 324 MPa / 47 ksi | 19 – 20 % | 120 HB | 283 MPa |
| T6 | 476 MPa / 69 ksi | 393 MPa / 57 ksi | 10 % | 125 HB | 283 MPa |
| T81, T851 | 483 MPa / 70 ksi | 448 MPa / 65 ksi | 6 % | 128 HB | 296 MPa |
| EN 485-2 minimums, bare | Thickness (mm) | Tensile Rm (MPa) | Yield Rp0.2 (MPa) | Elongation |
|---|---|---|---|---|
| O | 0.4 – 12.5 | ≤ 220 | ≤ 140 | 12 – 13 % (A50) |
| T3 | 0.4 – 1.5 | 435 | 290 | 12 % (A50) |
| T3 | 1.5 – 6.0 | 435 – 440 | 290 | 14 % (A50) |
| T351 | 6.0 – 12.5 | 440 | 290 | 13 % (A50) |
| T351 | 12.5 – 40 | 430 | 290 | 11 % (A) |
| T351 | 40 – 80 | 420 | 290 | 8 % (A) |
| T351 | 80 – 100 | 400 | 285 | 7 % (A) |
| T351 | 100 – 150 | 360 – 380 | 250 – 270 | 5 % (A) |
| T4 / T42 | 0.4 – 6.0 | 425 | 260 – 275 | 12 – 15 % (A50) |
| T8 / T851 | 0.4 – 12.5 | 460 | 400 | 5 – 6 % (A50) |
| T851 | 12.5 – 40 | 455 | 395 – 400 | 4 % (A) |
Summarised from EN 485-2; check the exact thickness band and the governing specification on the mill certificate.
Physical properties of 2024
- Density
- 2.78 g/cm³ (0.100 lb/in³)
- Modulus of elasticity
- about 73 GPa (10.6 Msi)
- Poisson's ratio
- 0.33
- Fatigue strength (5×10⁸ cycles, T3/T4)
- about 138 MPa
- Melting range
- about 502 – 638 °C
- Thermal conductivity
- about 121 W/m·K (T3/T4); about 151 W/m·K (T8)
- Electrical conductivity
- about 30 % IACS (T3/T4); about 38 % IACS (T8)
- Coefficient of thermal expansion
- about 23.2 µm/m·°C (20 – 100 °C)
2024 sheet and plate tempers
T351
Solution treated, stretched 1.5 – 3 %, naturally aged. Standard plate temper for machining.
T4 / T42
Solution treated and naturally aged without controlled cold work. T42 is the user-heat-treated equivalent, e.g. after forming from O.
T81 / T851
T3 sheet or T351 plate artificially aged. Higher yield strength, better stress-corrosion resistance and better elevated-temperature stability; lower toughness.
O
Annealed for stretch forming, drawing and tight bends before heat treatment.
T361 / T861
Higher cold-work variants offered for specific programmes; specify only when the drawing calls for them.
Specifications and equivalents
Bare sheet and plate
- AMS 4037
- 2024-T3 sheet and T351 plate
- AMS 4035
- 2024-O sheet and plate
- AMS-QQ-A-250/4
- 2024 sheet and plate, all common tempers (former QQ-A-250/4)
- ASTM B209 / ASME SB-209
- Sheet and plate, bare and Alclad
- EN 485-1/-2/-4, EN 573-3
- EN AW-2024 sheet, strip and plate
Alclad sheet and plate
- AMS 4041
- Alclad 2024-T3 sheet and T351 plate
- AMS-QQ-A-250/5
- Alclad 2024 sheet and plate (former QQ-A-250/5)
- ASTM B209
- Alclad 2024 in O, T3, T351, T4, T361, T81, T851
| System | Designation |
|---|---|
| Aluminum Association / UNS | 2024 / A92024 |
| European (EN) | EN AW-2024 / AlCu4Mg1 |
| German Werkstoff / DIN | 3.1355 / AlCuMg2 |
| ISO | AlCu4Mg1 |
| France (old NF) | AU4G1 |
| Japan (JIS) | A2024 |
| China (GB) | 2A12 (close equivalent) |
Sizes, weights and supply range
Supply range
- Thickness
- Sheet about 0.3 – 6 mm; plate 6 – about 150 mm
- Width
- 1000, 1220, 1250, 1500, 2000 mm; wider plate to about 2500 mm on request
- Length
- 2000 – 4000 mm standard; long sheets to about 12 m to order
- Imperial
- 48 × 144 in and 60 × 144 in sheet; thickness from 0.016 in
- Surface
- Mill finish, PVC-film protected; Alclad with bright clad faces
- Processing
- Cut-to-size blanks, waterjet profiling
2024 weighs 2.78 kg per m² for each millimetre of thickness. The plate weight calculator handles any size.
| Thickness (mm) | kg per m² | 1220 × 2440 mm (kg) | 1500 × 3000 mm (kg) |
|---|---|---|---|
| 0.5 | 1.39 | 4.1 | 6.3 |
| 0.8 | 2.22 | 6.6 | 10.0 |
| 1 | 2.78 | 8.3 | 12.5 |
| 1.27 | 3.53 | 10.5 | 15.9 |
| 1.6 | 4.45 | 13.2 | 20.0 |
| 2 | 5.56 | 16.6 | 25.0 |
| 2.5 | 6.95 | 20.7 | 31.3 |
| 3 | 8.34 | 24.8 | 37.5 |
| 4 | 11.12 | 33.1 | 50.0 |
| 5 | 13.90 | 41.4 | 62.5 |
| 6 | 16.68 | 49.7 | 75.1 |
| 10 | 27.80 | 82.8 | 125.1 |
| 12 | 33.36 | 99.3 | 150.1 |
| 20 | 55.60 | 165.5 | 250.2 |
| 25 | 69.50 | 206.9 | 312.8 |
| 40 | 111.20 | 331.0 | 500.4 |
| 50 | 139.00 | 413.8 | 625.5 |
| 80 | 222.40 | 662.0 | 1000.8 |
| 100 | 278.00 | 827.6 | 1251.0 |
Tolerances, testing and documentation
Thickness, width, length and flatness tolerances follow ANSI H35.2 for ASTM and AMS orders and EN 485-3/-4 for EN orders. Aerospace plate is commonly ultrasonically inspected to AMS-STD-2154 or ASTM B594, with the class stated on the order.
- Tensile tests per lot in the directions the specification requires
- Electrical conductivity and hardness checks of heat treatment
- Cladding thickness verification for Alclad material
- Surface inspection for scratches, roll marks and corrosion
- EN 10204 3.1 certificate with chemistry, properties and lot traceability
Forming, machining, joining and protection
Forming
T3 sheet forms moderately; minimum bend radii are typically about 2.5 – 4 × thickness depending on gauge. Severe forming is done in O or freshly quenched (W) condition.
Machining
T351 plate machines well; balance material removal on both faces to keep parts flat.
Joining
Riveting and bolting are standard; adhesive bonding is used for panels. 2024 is not fusion-welded in structure.
Corrosion protection
Use Alclad sheet where possible; anodise or conversion-coat and prime bare parts; seal faying surfaces.
Heat exposure
Naturally aged tempers change if held above about 120 °C; T81/T851 are better for warm service.
Handling
Protect Alclad surfaces: scratches through the cladding reduce corrosion protection.
Applications
- Fuselage skins and lower wing skins (Alclad 2024-T3)
- Frames, bulkheads, ribs and spars machined from T351 plate
- Stringers and stiffeners formed from sheet
- Repair doublers and patches on 2024 airframes
- Missile and space structures
- Truck wheels, tooling and high-strength sporting parts
2024 compared with 2524, 7075 and 6061
| Property | 2024-T3 | 2524-T3 | 7075-T6 | 6061-T6 |
|---|---|---|---|---|
| Typical tensile strength | ~483 MPa | ~460 – 480 MPa | ~572 MPa | ~310 MPa |
| Typical yield strength | ~345 MPa | ~340 MPa | ~503 MPa | ~276 MPa |
| Fatigue crack-growth resistance | Very good | Excellent | Fair | Good |
| Fracture toughness | Good | Very good | Moderate | Good |
| Corrosion (bare) | Low | Low | Low–moderate | Good |
| Typical use | Fuselage skin | Modern fuselage skin | Upper wing, fittings | Secondary structure |
How to order 2024 sheet and plate
- SpecifyAlloy (2024 or 2A12), bare or Alclad, temper, thickness, width, length or cut size, and quantity.
- Name the standardAMS 4037, AMS 4041, AMS-QQ-A-250/4 or /5, ASTM B209, EN 485 or your customer specification, plus ultrasonic class.
- QuoteWe confirm availability, tolerance, test scope, certification and delivery terms (EXW, FOB, CIF or DAP) for your port or site.
- Process and inspectSheets and plates are cut, film-protected and inspected for dimensions, flatness and surface.
- Document and shipEach lot ships with an EN 10204 3.1 mill test certificate traceable to the heat and lot, plus a packing list. Material is packed in seaworthy wooden cases with moisture protection; third-party inspection can be arranged on request.
References and standards
- ASTM B209 – Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- SAE AMS 4037 – Aluminum Alloy Sheet and Plate, 2024-T3 / T351
- EN 485-2 – Aluminium and aluminium alloys: sheet, strip and plate, mechanical properties
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM Handbook, Vol. 2 – Properties of Wrought Aluminum Alloys: 2024
2024 aircraft aluminium (aluminum) sheet: FAQ
What is Alclad 2024-T3?
2024-T3 sheet with a thin layer of 1230 high-purity aluminium bonded to each face. The cladding protects the core from corrosion and slightly lowers strength.
What is the difference between 2024-T3 and T351?
T3 applies to sheet that is cold worked by flattening; T351 applies to plate that is stretched to relieve stresses. Strength levels are similar.
Is 2A12 equivalent to 2024?
2A12 has essentially the same composition and is a close equivalent, but aerospace orders must state the designation and standard the drawing requires.
Why is 2024 used for fuselage skins instead of 7075?
2024-T3 resists fatigue crack growth and has higher toughness, which matters for pressurised skins loaded in tension. 7075 is stronger but less damage tolerant.
Can 2024 sheet be welded?
Not by conventional fusion welding for structure; riveting, bolting and bonding are used.
What sheet sizes are common?
1220 × 2440 mm, 1250 × 2500 mm, 1500 × 3000 mm and 48 × 144 in, with cut-to-size blanks on request.
Need 2024 sheet or plate?
Send bare or Alclad, temper, size, specification and quantity. We will reply with availability, certification and a delivered price.
