Sheet and plate
Bare or Alclad sheet from about 0.3 mm; plate in T351 up to heavy thicknesses for machined parts.
Alloy guide
2024 Aluminium Alloy: Tempers, Properties and Product Forms
2024 is the classic high-strength aluminium-copper-magnesium alloy of aircraft structures, valued for its fatigue resistance and damage tolerance. In the common T3 and T351 tempers it reaches about 470 – 485 MPa tensile strength, roughly 50 % more than 6061-T6, but it corrodes more easily and is not fusion welded. This guide covers its composition, tempers, standards, forms and how to work with it.
- System
- Al-Cu-Mg (2xxx)
- Main tempers
- T3 · T351 · T4 · T851
- Tensile (T3)
- ≈ 483 MPa typical
- Density
- 2.78 g/cm³
What is 2024 aluminium?
2024 was introduced in the early 1930s as a stronger successor to 2017 duralumin, with more magnesium. It became the standard material for aircraft fuselage skins, wing lower surfaces and other tension-loaded structure, and it is still one of the most widely specified aerospace aluminium alloys.
Its strength comes from copper and magnesium, which form fine precipitates during natural or artificial ageing. In the naturally aged T3 and T4 tempers the alloy combines high strength with excellent resistance to fatigue crack growth, which is why it is preferred for parts that see repeated loading, such as pressurised fuselage skins.
The copper that gives 2024 its strength also lowers its corrosion resistance. Sheet is therefore often supplied as Alclad, with a thin layer of pure aluminium bonded to each face, and bare parts are anodised, conversion coated and painted. Fusion welding causes hot cracking, so 2024 structures are riveted, bolted, bonded or friction stir welded.
2024 chemical composition (wt %)
| Element | Limit | Role |
|---|---|---|
| Copper (Cu) | 3.8 – 4.9 | Main strengthening element |
| Magnesium (Mg) | 1.2 – 1.8 | Adds strength with Cu (Al2CuMg phase) |
| Manganese (Mn) | 0.30 – 0.9 | Grain control, toughness |
| Silicon (Si) | ≤ 0.50 | Impurity |
| Iron (Fe) | ≤ 0.50 | Impurity; low Fe improves toughness |
| Chromium (Cr) | ≤ 0.10 | |
| Zinc (Zn) | ≤ 0.25 | |
| Titanium (Ti) | ≤ 0.15 | Grain refiner |
| Others each / total | ≤ 0.05 / 0.15 | |
| Aluminium | Remainder | About 90.7 – 94.7 % |
Aluminum Association limits, matched by EN AW-2024 (AlCu4Mg1). Higher-purity variants such as 2124 and 2524 lower Fe and Si for better fracture toughness.
2024 tempers explained
| Temper | Processing | Typical use |
|---|---|---|
| O | Annealed | Severe forming before heat treatment |
| T3 | Solution treated, cold worked, naturally aged | Sheet: fuselage skins, structural panels |
| T351 | Solution treated, stretched 1.5 – 3 %, naturally aged | Plate and bar for machined parts |
| T3510 / T3511 | Stretched extrusions (T3511 allows minor straightening) | Extruded bar, angles and profiles |
| T4 | Solution treated, naturally aged | Bar, wire, rivets; parts to be formed |
| T42 | Solution treated and naturally aged by the user | Parts heat treated from O temper |
| T62 | Solution treated and artificially aged by the user | Better stress-corrosion resistance, lower ductility |
| T81 / T851 | T3 / T351 then artificially aged | Higher yield, better stress-corrosion and exfoliation resistance |
| T8511 | Stretched extrusion, artificially aged | Profiles for elevated-temperature service |
Typical properties of 2024 by temper
| Temper | Tensile | Yield (0.2 %) | Elongation | Shear | Hardness |
|---|---|---|---|---|---|
| O | 186 MPa (27 ksi) | 76 MPa (11 ksi) | 20 % | 125 MPa | 47 HB |
| T3 (bare sheet) | 483 MPa (70 ksi) | 345 MPa (50 ksi) | 18 % | 283 MPa | 120 HB |
| T4 / T351 | 469 MPa (68 ksi) | 324 MPa (47 ksi) | 19 – 20 % | 283 MPa | 120 HB |
| T851 | 483 MPa (70 ksi) | 448 MPa (65 ksi) | 6 % | 296 MPa | 128 HB |
These are typical values (ASM data). Specified minimums are lower and vary with product form and thickness; Alclad sheet is a few percent weaker because the cladding carries little load. Fatigue strength is about 138 MPa (20 ksi) at 5 × 108 cycles in T3/T4.
Physical properties
- Density
- 2.78 g/cm³ (0.100 lb/in³)
- Modulus of elasticity
- 73.1 GPa (10,600 ksi)
- Melting range
- about 502 – 638 °C
- Thermal conductivity
- 121 W/m·K (T3); about 190 W/m·K (O)
- Electrical conductivity
- about 30 % IACS (T3); about 50 % IACS (O)
- Thermal expansion
- 23.2 µm/m·°C (20 – 100 °C)
2024 standards and equivalents
| Product | Common specifications |
|---|---|
| Sheet and plate | ASTM B209, AMS-QQ-A-250/4 (bare), AMS-QQ-A-250/5 (Alclad), AMS 4037, EN 485 |
| Bar and rod | ASTM B211 (cold finished), ASTM B221 (extruded), AMS-QQ-A-225/6, EN 754 / EN 755 |
| Extruded profiles | ASTM B221, AMS-QQ-A-200/3, EN 755 |
| Tube | ASTM B210 (drawn), ASTM B241 (seamless extruded), AMS-WW-T-700/3 |
| Rivet and cold-heading wire | ASTM B316 |
| Forgings | ASTM B247 |
| System | Designation |
|---|---|
| UNS | A92024 |
| EN | EN AW-2024 / AlCu4Mg1 |
| Werkstoff | 3.1355 |
| ISO | AlCu4Mg1 |
| JIS | A2024 |
| Russia (GOST) | Д16 (1160) |
| China (GB) | 2024; 2A12 is a close national grade |
2024 product forms Metline supplies
Bar and rod
Round, square, hexagon and flat bar, extruded (T3511) or cold finished (T351, T4) for precision machining.
Tube
Seamless extruded and drawn tube for aircraft structure, hydraulic and actuator parts.
Extruded profiles
Angles, T-sections, channels, Z-sections and custom stringers in T3511 or T8511.
Forgings
Hand and die forgings, rings and discs to drawing.
Wire
Cold-heading and rivet wire in O, H13 and T4 for DD rivets and high-strength screws.
Machining, forming, joining and corrosion protection
Machining
Machines very well in T3, T351 and T4: short chips and a good finish. Use sharp carbide tools and coolant. The O temper is gummy.
Forming
Form in O or freshly quenched (W) condition, then age. T3 allows only moderate bends; check minimum bend radii for thickness.
Welding
Fusion welding causes hot cracking and weak joints. Use riveting, bolting, adhesive bonding or friction stir welding.
Corrosion
Use Alclad sheet, anodising (often sulphuric or boric-sulphuric), conversion coatings and primer. Avoid contact with carbon fibre or copper without isolation.
Stress corrosion
T3/T351 is susceptible in the short-transverse direction of thick sections; T8 tempers are much more resistant.
Temperature
Loses strength progressively above about 120 °C; T8x tempers hold up better than T3.
2024 compared with 7075, 6061 and 2017
| Property | 2024-T351 | 7075-T651 | 6061-T651 | 2017-T4 |
|---|---|---|---|---|
| Typical tensile | 469 MPa | 572 MPa | 310 MPa | 427 MPa |
| Typical yield | 324 MPa | 503 MPa | 276 MPa | 276 MPa |
| Fatigue / damage tolerance | Excellent | Good | Good | Good |
| Corrosion resistance | Fair | Fair | Good | Fair |
| Weldability | Poor | Poor | Good | Poor |
| Typical role | Tension skins, fittings | Compression structure, high-stress parts | General engineering | Rivets, machined parts |
A common airframe rule of thumb uses 2024 for tension-dominated structure, such as lower wing skins and fuselage skins, and 7075 for compression-dominated structure, such as upper wing skins and stringers. 6061 is the economical, weldable option where 2024 strength is not needed.
Applications of 2024 aluminium
- Aerospace: fuselage skins, wing tension members, bulkheads, fittings and rivets
- Defence: airframe parts, missile structures and military vehicle components
- Transport: truck wheels, high-performance vehicle parts and rail interiors
- Machinery: gears, shafts, fixtures and machined parts from bar and plate
- Fasteners: DD rivets, screws and bolts from cold-heading wire
- Sports equipment: components where high strength-to-weight is needed
How to order 2024 from Metline
- SpecifyForm, temper (e.g. 2024-T351), dimensions, quantity and standard (ASTM, AMS, EN).
- InspectionState ultrasonic inspection class, test direction or third-party inspection if needed.
- QuoteWe confirm availability, certification and EXW, FOB, CIF or DAP terms.
- ShipMaterial is packed in seaworthy cases with an EN 10204 3.1 mill certificate.
References and standards
- ASTM B209 – Aluminum and Aluminum-Alloy Sheet and Plate
- SAE AMS-QQ-A-250/4 – Aluminum Alloy 2024, Plate and Sheet
- EN 573-3 – Chemical composition and form of wrought products
- ASM International – Properties of Wrought Aluminum and Aluminum Alloys: 2024
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
2024 aluminium (aluminum): frequently asked questions
What is 2024 aluminium used for?
Mainly aircraft structure (fuselage skins, wing tension members, fittings and rivets), plus defence hardware, truck wheels, fasteners and highly stressed machined parts.
Is 2024 stronger than 6061?
Yes. 2024-T3 has about 483 MPa typical tensile strength versus about 310 MPa for 6061-T6, and much better fatigue resistance. 6061 is easier to weld and more corrosion resistant.
Can 2024 aluminium be welded?
Not by conventional fusion welding, which causes cracking. Friction stir welding works; otherwise use riveting, bolting or bonding.
What is the difference between 2024-T3 and T351?
Both are solution treated and naturally aged. T3 (mostly sheet) includes cold work for flatness; T351 (plate and bar) is stretched to relieve residual stress so it stays stable when machined.
What is Alclad 2024?
2024 sheet with a thin layer of high-purity aluminium on each face. The cladding protects the core from corrosion sacrificially, at the cost of slightly lower strength.
What is the Russian equivalent of 2024?
Д16 (1160). China's 2A12 is a close national grade with a similar composition.
Sourcing 2024 aluminium?
Send form, temper, size and quantity. Metline will reply with availability, certification and a delivered price worldwide.
