Turning
Use sharp carbide inserts with a positive rake and chip breaker. 2024 gives longer chips than 2011, so chip control matters on automatic lathes.
High-strength round bar
2024 Aluminium Round Bar
2024 aluminium round bar is a high-strength, fatigue-resistant rod used for shafts, fasteners, fittings and machined aerospace parts. It is supplied cold-finished in small diameters, extruded or rolled in larger ones, most often in the stress-relieved T351 temper. Metline supplies 2024 round bar in metric and inch diameters, cut to length and certified to ASTM, AMS or EN, to buyers worldwide.
- Alloy
- 2024 (Al-Cu-Mg)
- Tempers
- T4, T351, T3511, T851
- Diameters
- Small drawn rod to large rolled bar
- Standards
- ASTM B211 · AMS 4120 · EN 754
2024 round bar at a glance
Round bar is the most common way 2024 is bought for machining. Turned shafts, pins, bolts, bushings, hydraulic pistons and aircraft fittings all start as 2024 rod, because the alloy combines high strength with the best fatigue resistance of the common high-strength aluminium grades.
Unlike 6061 round bar, which is almost always extruded and artificially aged, 2024 rod is used mostly in the naturally aged T4 or T351 condition. Its strength comes from copper and magnesium precipitating at room temperature after quenching. For round bar that will be turned, the stress-relieved T351 temper (rolled bar) or T3511 (extruded bar) is preferred because stretching removes most of the quench stress that would otherwise make long parts bow during machining.
This page focuses on round bar: production routes, diameters, weights and tolerances. For a general overview of the alloy in all bar shapes, see our 2024 bar and rod page.
Cold-finished, extruded and rolled 2024 round bar
| Route | Typical diameter range | Tempers | Main standard | Best for |
|---|---|---|---|---|
| Cold-finished (drawn) | Small to medium diameters | T4, T351, T851 | ASTM B211, AMS 4120 | Screw-machine parts, fasteners, close-tolerance rod for bar feeders |
| Extruded | Medium to large diameters | T3511, T8511, T4 | ASTM B221, AMS-QQ-A-200/3 | General machining stock, longer lengths |
| Rolled / forged bar | Large diameters | T351, T851 | ASTM B211, AMS 4120, ASTM B247 (forgings) | Large turned and bored parts, forging stock |
| Centreless ground | Small to medium diameters | T4, T351 | Ground from drawn or extruded bar | Precision shafts and pins with fine finish |
The route matters because tolerances and surface quality differ. Cold-finished rod has the tightest diameter tolerance and a bright surface; extruded bar has wider tolerances and may need a skim cut; rolled bar can show a slightly coarser surface layer. Tell us how the bar will be processed so we can recommend the most economical route.
2024 chemical composition (wt %)
Registered Aluminum Association limits for 2024, used by ASTM, AMS and EN 573-3 (EN AW-2024):
| 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 round bar
Typical values below come from Aluminum Association / ASM data. Specified minimums depend on diameter and route and are lower; large-diameter bar has slightly lower minimums because the centre cools more slowly when quenched. The mill certificate reports values for your lot.
| Temper | Tensile (typical) | Yield (typical) | Elongation | Hardness | Shear strength |
|---|---|---|---|---|---|
| O | 186 MPa | 76 MPa | 20 % | 47 HB | 125 MPa |
| T4 / T351 | 469 MPa | 324 MPa | 19 – 20 % | 120 HB | 283 MPa |
| T851 | 483 MPa | 448 MPa | 6 % | 128 HB | 296 MPa |
Physical properties
- Density
- 2.78 g/cm³ (0.100 lb/in³)
- Modulus of elasticity
- about 73 GPa
- Fatigue strength (5×10⁸ cycles, T4)
- about 138 MPa
- Thermal conductivity
- about 121 W/m·K (T4), higher in T8
- Electrical conductivity
- about 30 % IACS (T4)
- Coefficient of thermal expansion
- about 23.2 µm/m·°C
2024 round bar diameters and weights
2024 round bar is available in both metric and imperial diameters. The tables give theoretical weights for solid bar; actual weights vary slightly with tolerance.
| Diameter (mm) | kg per metre | 3 m bar (kg) | 6 m bar (kg) |
|---|---|---|---|
| 5 | 0.055 | 0.16 | 0.33 |
| 8 | 0.140 | 0.42 | 0.84 |
| 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 |
| 35 | 2.67 | 8.02 | 16.05 |
| 40 | 3.49 | 10.48 | 20.96 |
| 50 | 5.46 | 16.38 | 32.75 |
| 60 | 7.86 | 23.58 | 47.16 |
| 70 | 10.70 | 32.10 | 64.19 |
| 80 | 13.97 | 41.92 | 83.84 |
| 100 | 21.83 | 65.50 | 131.00 |
| 120 | 31.44 | 94.32 | 188.65 |
| 150 | 49.13 | 147.38 | 294.76 |
| 200 | 87.34 | 262.01 | 524.02 |
| 250 | 136.46 | 409.39 | 818.78 |
Imperial sizes, based on 0.100 lb/in³:
| Diameter | lb per ft | kg per m | 12 ft bar (lb) |
|---|---|---|---|
| 0.25 in (6.3 mm) | 0.059 | 0.088 | 0.7 |
| 0.375 in (9.5 mm) | 0.133 | 0.198 | 1.6 |
| 0.5 in (12.7 mm) | 0.236 | 0.352 | 2.8 |
| 0.625 in (15.9 mm) | 0.368 | 0.550 | 4.4 |
| 0.75 in (19.0 mm) | 0.530 | 0.792 | 6.4 |
| 1 in (25.4 mm) | 0.942 | 1.409 | 11.3 |
| 1.25 in (31.8 mm) | 1.473 | 2.201 | 17.7 |
| 1.5 in (38.1 mm) | 2.121 | 3.169 | 25.4 |
| 2 in (50.8 mm) | 3.770 | 5.635 | 45.2 |
| 2.5 in (63.5 mm) | 5.890 | 8.804 | 70.7 |
| 3 in (76.2 mm) | 8.482 | 12.678 | 101.8 |
| 4 in (101.6 mm) | 15.080 | 22.538 | 181.0 |
| 5 in (127.0 mm) | 23.562 | 35.216 | 282.7 |
| 6 in (152.4 mm) | 33.929 | 50.711 | 407.2 |
| 8 in (203.2 mm) | 60.319 | 90.153 | 723.8 |
Diameter tolerance, straightness and inspection
Tolerance references
- Cold-finished rod
- ASTM B211 / ANSI H35.2 standard tolerances; EN 754-3 for drawn round bar
- Extruded rod
- ASTM B221 / ANSI H35.2; EN 755-3 for extruded round bar
- Straightness
- Per the same standards; T351 / T3511 stress relief improves straightness after machining
- Ground bar
- Precision tolerances (for example h9 or tighter) on request
- Ultrasonic testing
- AMS-STD-2154 or ASTM B594 classes for aerospace and critical parts on request
- Certification
- EN 10204 3.1 mill test certificate with chemistry, tensile results and heat number
For bar-feeder work, specify the tolerance class and the end condition (saw-cut, chamfered). For large-diameter bar, ask for the ultrasonic class at the enquiry stage, because it affects which mill lots are suitable.
Turning and finishing 2024 round bar
Drilling and threading
Drills and taps well; use cutting fluid to avoid built-up edge. Roll threading works well in T4.
Distortion control
Use T351 or T3511 and take balanced cuts on long slender parts; leave a finishing allowance for straightening if needed.
Surface protection
Anodise or apply conversion coating after machining. Hard anodising increases wear resistance on shafts and pistons.
Joining
Not suited to arc welding. Use threads, pins, interference fits or adhesive bonding.
Shot peening
Commonly used on fatigue-critical 2024 parts to add compressive surface stress.
Typical uses of 2024 round bar
- Aerospace: bolts, pins, actuator rods, hinge fittings and turned structural parts
- Fasteners: screws, rivets and studs from T4 rod
- Hydraulics: pistons, rods and valve components
- Automotive and motorsport: drive shafts, suspension and steering components
- Machinery: gears, spindles, couplings and rollers
- Medical and instruments: orthopaedic fixture parts and precision instrument components
How to order 2024 round bar
- SpecifyDiameter (metric or inch), temper (T4, T351, T3511 or T851), length and quantity.
- Confirm the standardASTM B211 or B221, AMS 4120 or AMS-QQ-A-225/6, or EN 754-2 / EN 755-2, with any tolerance class and ultrasonic requirement.
- QuoteWe confirm availability, tolerance class, certification and delivery terms (EXW, FOB, CIF or DAP) for your destination port or site.
- Process and inspectBars are cut to length, checked for diameter and straightness, end-marked with alloy, temper and heat number, and protected for transit.
- 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
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products (The Aluminum Association)
- EN 754-3 – Cold drawn rod/bar: round bars, tolerances on dimensions and form
- ASM Handbook, Vol. 2 – Properties of Wrought Aluminum and Aluminum Alloys: 2024
2024 aluminium (aluminum) round bar: frequently asked questions
Which temper of 2024 round bar is best for machining?
T351 for rolled bar or T3511 for extruded bar. Both are stretched to relieve quench stress, so long turned parts stay straighter. T4 is fine for small cold-finished rod.
How much does 2024 round bar weigh?
At 2.78 g/cm³, a 25 mm bar weighs about 1.36 kg/m and a 50 mm bar about 5.46 kg/m. In inch sizes, 1 in rod weighs about 0.94 lb/ft.
What diameters of 2024 round bar are available?
From small cold-drawn rod of a few millimetres up to large rolled or forged bar of several hundred millimetres. Common inch sizes run from 1/4 in to 8 in; confirm availability for your exact diameter and temper.
Is 2024 round bar suitable for shafts?
Yes. Its high fatigue strength makes it a good shaft material where weight matters; anodise or hard-anodise bearing surfaces to improve wear and corrosion resistance.
Can you cut 2024 round bar to length?
Yes. We supply random or fixed lengths and saw-cut pieces to your dimensions, with end marking for traceability.
What is the difference between 2024 and 2024A?
Not much in practice. In Europe, aerospace specifications sometimes use variants with tighter iron and silicon limits for better toughness. Follow the designation and specification on your drawing.
Need 2024 round bar?
Send the diameter, temper, length, quantity and destination, and we will reply with availability and a delivered price.
