Round bar and rod
Cold-finished or extruded, about 3 – 100 mm diameter, for turned fittings, spacers and pins.
Aerospace bar
3003 Aerospace Aluminium Bar & Rod
3003 bar and rod is the formable, corrosion-resistant aluminium used in aircraft for lightly loaded parts that are bent, flared, headed or welded: fluid-system fittings, spacers, rivets, brackets and ducting hardware. Metline supplies 3003 round, square, hex and flat bar in O and H-tempers to ASTM B211 and B221, cut to length and shipped worldwide.
- Alloy
- 3003 (Al-Mn)
- Tempers
- O, H12, H14, H16, H18
- Standards
- ASTM B211 · ASTM B221
- Density
- 2.73 g/cm³
Where 3003 bar fits in aerospace
3003 is aluminium with about 1.2 % manganese. It cannot be heat-treated; it gains strength only by cold work, which is what the H12 to H18 tempers describe. It is around 20 % stronger than commercially pure 1100 while keeping almost the same formability, weldability and corrosion resistance.
In an aircraft, 3003 bar is never a primary structural material; 2024, 7075 and 6061 do that job. It is chosen for secondary parts where formability, weldability or corrosion resistance matter more than strength: fittings and adapters for low-pressure fluid lines, spacers and bushings in non-structural assemblies, cold-headed rivets and pins, brackets for ducting and wiring, and welded parts for fuel, oil and heat-exchanger systems.
Federal specification QQ-A-225/2, which once covered 3003 bar, rod and wire, has been cancelled; ASTM B211 (cold-finished) and ASTM B221 (extruded) now govern, and we certify to them when older drawings still cite QQ-A-225/2.
3003 chemical composition (wt %)
Registered Aluminum Association limits, applied by ASTM B211, B221 and EN 573-3 (EN AW-3003, AlMn1Cu).
| Element | Limit | Comment |
|---|---|---|
| Manganese (Mn) | 1.0 – 1.5 | Main alloying element; raises strength about 20 % over 1100 |
| Copper (Cu) | 0.05 – 0.20 | Small addition for strength |
| Silicon (Si) | 0.60 max | Impurity |
| Iron (Fe) | 0.70 max | Impurity |
| Zinc (Zn) | 0.10 max | Impurity |
| Others each / total | 0.05 / 0.15 | |
| Aluminium | Remainder | About 96.8 – 98.9 % |
Mechanical and physical properties by temper
Each step from O to H18 roughly doubles yield strength while reducing elongation. H12 is quarter-hard, H14 half-hard, H16 three-quarter-hard and H18 full-hard.
| Temper | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| O | 110 MPa / 16 ksi | 40 MPa / 6 ksi | 30 – 40 % | 28 HB |
| H12 | 130 MPa / 19 ksi | 125 MPa / 18 ksi | 10 – 20 % | 35 HB |
| H14 | 150 MPa / 22 ksi | 145 MPa / 21 ksi | 8 – 16 % | 40 HB |
| H16 | 180 MPa / 26 ksi | 170 MPa / 25 ksi | 5 – 14 % | 47 HB |
| H18 | 200 MPa / 29 ksi | 185 MPa / 27 ksi | 4 – 10 % | 55 HB |
Typical values (Aluminum Association / ASM). Elongation depends on product form and thickness. Specified minimums are those of the ordered standard.
Physical properties
- Density
- 2.73 g/cm³ (0.0986 lb/in³)
- Melting range
- about 643 – 654 °C
- Modulus of elasticity
- about 69 GPa (10,000 ksi)
- Thermal conductivity
- about 190 W/m·K (O) to 155 W/m·K (H18)
- Electrical conductivity
- about 50 % IACS (O) to 40 % IACS (H18)
- Coefficient of thermal expansion
- about 23.2 µm/m·°C (20 – 100 °C)
3003 bar forms and sizes
Square bar
Sharp or radiused corners for machined blocks and brackets.
Hexagon bar
For nuts, adapters and fluid fittings.
Flat bar
For straps, clips and formed brackets.
Precision-drawn bar
Close tolerance, bright surface, suited to automatic lathes.
Wire and rivet rod
Smaller diameters for cold heading.
Typical supply
- Lengths
- 3 m and 6 m, or cut to length
- Standards
- ASTM B211, ASTM B221, EN 754, EN 755
- Certification
- EN 10204 3.1 mill test certificate
A 3003 round bar weighs about 0.002144 × d² kg per metre (d in mm): 25 mm is about 1.34 kg/m and 50 mm about 5.4 kg/m.
Forming, welding and machining
- Forming: excellent in O and H12; tight bends and heading are easy. H16 and H18 need larger radii.
- Welding and brazing: readily welded by TIG and MIG with 1100 or 4043 filler, and well suited to brazing.
- Machining: soft and gummy in O; harder tempers machine better. Use sharp, high-rake tools and lubricant.
- Corrosion: very good in atmosphere and many fluids; anodising adds protection and appearance.
- Annealing: about 415 °C restores full softness after cold work.
3003 compared with 1100, 5052 and 6061 bar
| Factor | 3003-H14 | 1100-H14 | 5052-H32 | 6061-T6 |
|---|---|---|---|---|
| Typical tensile strength | 150 MPa | 125 MPa | 230 MPa | 310 MPa |
| Formability | Excellent | Excellent | Very good | Fair |
| Weldability | Excellent | Excellent | Excellent | Good |
| Heat-treatable | No | No | No | Yes |
If 3003 is not strong enough, 5052 is the next step without heat treatment; 6061-T6 doubles strength again at the cost of formability.
References and standards
- ASTM B211 – Aluminum and Aluminum-Alloy Rolled or Cold-Finished Bar, Rod, and Wire
- 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
3003 aerospace aluminium (aluminum) bar: FAQ
Is 3003 used for aircraft structure?
Not for primary structure. It is used for secondary parts such as fittings, spacers, rivets and brackets where formability, weldability and corrosion resistance matter more than strength.
What replaced QQ-A-225/2 for 3003 bar?
The federal specification is cancelled; ASTM B211 covers cold-finished 3003 bar, rod and wire, and ASTM B221 covers extruded bar.
Can 3003 be heat-treated?
No. It is strengthened only by cold work (H-tempers) and can be softened by annealing.
Which temper should I choose?
O or H12 for heavy forming and heading, H14 as a general-purpose balance, and H16 or H18 where more strength is needed and forming is limited.
What is the density of 3003?
About 2.73 g/cm³, roughly a third of the density of steel.
Need 3003 bar for aircraft fittings?
Send the shape, size, temper and quantity. We will reply with availability and a delivered price.
