2024-T4
Solution heat-treated and naturally aged. Standard for cold-finished rod and wire, including rivet and screw stock.
Aerospace-grade high-strength bar
2024 Aluminium Bar & Rod
2024 aluminium bar is the high-strength aluminium-copper-magnesium alloy best known from aircraft structures. In T4 and T351 it reaches about 470 MPa tensile strength with excellent fatigue resistance, and it machines well. Metline supplies 2024 round, square, hexagonal and flat bar in naturally aged, stress-relieved and artificially aged tempers, certified to ASTM, AMS or EN, to customers worldwide.
- Alloy
- 2024 (Al-Cu-Mg)
- Tempers
- T4, T351, T3511, T851, O
- Strength
- ≈ 469 MPa UTS (T351)
- Standards
- ASTM B211 · AMS 4120 · EN 754
What is 2024 aluminium bar?
2024 was introduced in the early 1930s as a stronger successor to 2017, by raising the magnesium content to about 1.5 %. It quickly became the standard aircraft alloy and is still specified wherever high strength must be combined with good fatigue performance.
The alloy gets its strength from natural ageing: after solution heat treatment and quenching, copper and magnesium form fine clusters and precipitates at room temperature. Bar is normally supplied in T4 (naturally aged) or T351 (also stretched to relieve stress). In these tempers 2024 offers a yield strength of around 325 MPa and a tensile strength around 470 MPa, plus a combination of fatigue resistance and fracture toughness that 7075 does not match.
Bar is the starting stock for many machined parts: aircraft fittings, shafts, gears, fasteners, hydraulic pistons and high-stress components in motorsport and defence. Because 2024 has limited corrosion resistance and is not suited to fusion welding, parts are protected by anodising or conversion coating and joined mechanically.
2024 chemical composition (wt %)
Registered Aluminum Association limits, used by ASTM B211, ASTM B221, AMS 4120 and EN 573-3 (EN AW-2024, AlCu4Mg1). The actual analysis of your lot is reported on its mill test certificate.
| Element | Minimum | Maximum | Role |
|---|---|---|---|
| Silicon (Si) | — | 0.50 | Impurity |
| Iron (Fe) | — | 0.50 | Impurity; kept low for toughness |
| Copper (Cu) | 3.8 | 4.9 | Main strengthening element |
| Manganese (Mn) | 0.30 | 0.9 | Strength and grain control |
| Magnesium (Mg) | 1.2 | 1.8 | Combines with Cu for natural age hardening |
| Chromium (Cr) | — | 0.10 | |
| Zinc (Zn) | — | 0.25 | Impurity |
| Titanium (Ti) | — | 0.15 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 90.7 – 94.7 % |
Mechanical properties of 2024 bar by temper
Typical values from Aluminum Association / ASM data. Specified minimums vary with temper, diameter or thickness and product route (rolled, drawn or extruded), and are the values to design to.
| Temper | Tensile strength (typical) | Yield strength (typical) | Elongation | Brinell hardness |
|---|---|---|---|---|
| O (annealed) | 186 MPa / 27 ksi | 76 MPa / 11 ksi | 20 % | 47 HB |
| T3 | 483 MPa / 70 ksi | 345 MPa / 50 ksi | 18 % | 120 HB |
| T4 / T351 | 469 MPa / 68 ksi | 324 MPa / 47 ksi | 19 – 20 % | 120 HB |
| T851 | 483 MPa / 70 ksi | 448 MPa / 65 ksi | 6 % | 128 HB |
Physical properties (T4 / T351)
- Density
- 2.78 g/cm³ (0.100 lb/in³)
- Melting range
- about 502 – 638 °C
- Modulus of elasticity
- about 73 GPa (10,600 ksi)
- Shear strength
- about 283 MPa (41 ksi)
- Fatigue strength (5×10⁸ cycles)
- about 138 MPa (20 ksi)
- Thermal conductivity
- about 121 W/m·K
- Electrical conductivity
- about 30 % IACS
- Coefficient of thermal expansion
- about 23.2 µm/m·°C (20 – 100 °C)
Which 2024 bar temper should you order?
2024-T351
Solution treated, stretched to relieve stress and naturally aged. The usual temper for rolled bar and the best choice for heavily machined parts.
2024-T3511 / T3510
Stress-relieved tempers for extruded bar and shapes. T3511 permits minor straightening after stretching.
2024-T851 / T8511
Stretched and artificially aged. Higher yield strength, lower elongation and better resistance to stress-corrosion cracking; suited to service at moderately elevated temperature.
2024-T6 / T62
Artificially aged without stretching, or heat treated by the user from O temper.
2024-O
Annealed for cold forming and heading before heat treatment.
2024 bar shapes and how they are made
| Form | Production route | Usual tempers | Typical use |
|---|---|---|---|
| Round bar & rod | Cold-drawn, rolled or extruded | T4, T351, T3511, T851 | Shafts, pins, fasteners, turned parts |
| Square bar | Extruded or rolled | T351, T3511 | Milled blocks, fittings, linkages |
| Hexagonal bar | Drawn or extruded | T4, T351 | Nuts, fittings, screw-machine parts |
| Flat / rectangular bar | Extruded or rolled | T3511, T351 | Brackets, rails, spar caps, machined strips |
| Ground and polished bar | Centreless ground from drawn or extruded bar | T4, T351 | Precision shafts and bushes |
Weight of solid round 2024 bar at 2.78 g/cm³:
| Diameter (mm) | kg per metre | 3 m bar (kg) | 6 m bar (kg) |
|---|---|---|---|
| 6 | 0.079 | 0.24 | 0.47 |
| 10 | 0.218 | 0.66 | 1.31 |
| 12 | 0.314 | 0.94 | 1.89 |
| 16 | 0.559 | 1.68 | 3.35 |
| 20 | 0.873 | 2.62 | 5.24 |
| 25 | 1.36 | 4.09 | 8.19 |
| 30 | 1.97 | 5.90 | 11.79 |
| 40 | 3.49 | 10.48 | 20.96 |
| 50 | 5.46 | 16.38 | 32.75 |
| 60 | 7.86 | 23.58 | 47.16 |
| 80 | 13.97 | 41.92 | 83.84 |
| 100 | 21.83 | 65.50 | 131.00 |
| 150 | 49.13 | 147.38 | 294.76 |
| 200 | 87.34 | 262.01 | 524.02 |
2024 bar standards and international equivalents
| System | Designation | Bar and rod standard |
|---|---|---|
| Aluminum Association / ASTM | 2024 | ASTM B211 (rolled / cold-finished), ASTM B221 (extruded) |
| Aerospace (SAE) | 2024-T4 / T351 | AMS 4120 (bar, rod, wire); AMS-QQ-A-225/6 (bar); AMS-QQ-A-200/3 (extrusions) |
| UNS | A92024 | — |
| European (EN) | EN AW-2024 / AlCu4Mg1 | EN 754-2, EN 755-2, EN 573-3 |
| German Werkstoff | 3.1355 | DIN EN 754 / 755 |
| ISO | AlCu4Mg1 | ISO 209 |
| Japan (JIS) | A2024 | JIS H4040 |
| China (GB) | 2024; close to 2A12 | GB/T 3190, GB/T 3191 |
Tolerances follow the product standard: ASTM B211 / ANSI H35.2 for drawn and rolled bar, ASTM B221 for extrusions, and EN 754-3, EN 755-3 to -9 for European orders. Aerospace orders often add ultrasonic inspection to AMS-STD-2154 for larger bar.
Machining, joining, forming and corrosion protection
Machining
Machines well in T4, T351 and T851, producing manageable chips and a good finish. Use carbide tools, positive rake and flood coolant; T351 holds dimensions on asymmetric parts.
Welding
Not suitable for conventional arc welding because of hot cracking and loss of strength. Friction-stir welding and mechanical fastening are used instead.
Forming
Form in O or freshly quenched W condition, then age. T4 can take moderate bends with generous radii.
Corrosion
Lower resistance than 5xxx and 6xxx alloys. Anodise (sulphuric or boric-sulphuric), conversion-coat or prime and paint. T8 tempers resist stress-corrosion cracking better than T3 / T4.
Heat treatment
Solution treat at about 495 °C, quench, then age naturally (T4) or artificially at around 190 °C (T8). Follow AMS 2770 for aerospace parts.
Temperature
Keeps useful strength up to about 120 – 150 °C in T4; T8 tempers are preferred for longer exposure at elevated temperature.
Where 2024 bar is used
- Aircraft: fittings, hinges, actuator parts, bolts, rivets and machined structural components
- Defence: missile parts, ordnance components and military vehicle fittings
- Motorsport and automotive: suspension and drivetrain parts, wheel hubs and high-load brackets
- Hydraulics: pistons, valve parts and high-pressure fittings
- Fasteners: screws, bolts, nuts and rivets made from T4 rod and wire
- Machinery: gears, shafts, couplings and orthopaedic or instrument components
2024 compared with 2014, 6061 and 7075 bar
| Property | 2024-T351 | 2014-T6 | 6061-T6 | 7075-T6 |
|---|---|---|---|---|
| Typical tensile strength | 469 MPa | 483 MPa | 310 MPa | 572 MPa |
| Typical yield strength | 324 MPa | 414 MPa | 276 MPa | 503 MPa |
| Fatigue strength (5×10⁸) | 138 MPa | 124 MPa | 96 MPa | 159 MPa |
| Fracture toughness | Very good | Good | Very good | Moderate |
| Weldability (arc) | Poor | Poor | Good | Poor |
| Corrosion resistance | Fair | Fair | Good | Fair |
7075 is stronger in static strength, but 2024 tolerates cracks and cyclic loads better, which is why it remains the alloy of choice for fatigue-critical parts. See our article on the differences between 2024 and 7075.
How to order 2024 bar from Metline
- SpecifyAlloy and temper (e.g. 2024-T351), shape, size, length and quantity, plus the drawing for cut blanks.
- Confirm the standardASTM B211 / B221, AMS 4120 or AMS-QQ-A-225/6, or EN 754 / EN 755; add any ultrasonic class or grain-direction requirements.
- QuoteWe confirm availability, tolerance class, certification and delivery terms (EXW, FOB, CIF or DAP) for your destination port or site.
- Process and inspectBars are saw-cut, checked for size, straightness and surface, and ultrasonically tested when the order requires it.
- Document and shipEach lot ships with an EN 10204 3.1 mill test certificate and packing list. Bars are bundled or cased in seaworthy wooden boxes with moisture protection; third-party inspection can be arranged on request.
References and standards
- ASTM B211/B211M – Aluminum and Aluminum-Alloy Rolled or Cold-Finished Bar, Rod, and Wire
- SAE AMS 4120 – Aluminum Alloy Bars, Rods, and Wire, 2024-T4 / T351
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- EN 573-3 – Chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
2024 aluminium (aluminum) bar: frequently asked questions
What is the difference between 2024-T4 and 2024-T351 bar?
Both are solution treated and naturally aged with similar strength. T351 bar is also stretched about 1 – 3 % to relieve quench stresses, so it moves less during machining.
Is 2024 stronger than 6061?
Yes. 2024-T351 has about 469 MPa tensile and 324 MPa yield strength, against about 310 and 276 MPa for 6061-T6, and a much higher fatigue strength. 6061 is easier to weld and more corrosion resistant.
Can 2024 aluminium bar be welded?
Not by conventional MIG or TIG welding; the alloy is prone to hot cracking and loses strength. Friction-stir welding and mechanical fastening are the usual joining methods.
Does 2024 bar need corrosion protection?
Generally yes. Its copper content lowers corrosion resistance, so parts are anodised, conversion-coated or painted, particularly in marine or humid conditions.
What is the European equivalent of 2024?
EN AW-2024 (AlCu4Mg1, Werkstoff 3.1355). The Chinese grade 2A12 is similar but not identical.
Do you supply 2024 bar with aerospace certification?
Yes, 2024 bar can be supplied certified to AMS 4120 or AMS-QQ-A-225/6 with an EN 10204 3.1 certificate; ultrasonic test reports can be added for aerospace orders.
Need 2024 bar or rod?
Send shape, size, temper, specification, quantity and destination. Our team will reply with availability and a delivered quotation.
