T6
Solution treated and aged, not stretched. Fine for sections used as extruded or lightly machined.
Extruded shapes to aerospace specifications
6061 Aerospace Aluminium Extrusion Profiles
6061 aerospace profiles are extruded angles, channels, tees, I-sections, Z-sections and custom shapes in 6061, certified to specifications such as AMS 4150 (T6), AMS 4161 (T4), AMS 4160 (O) and AMS 4173 (T6510/T6511). They give designers a weldable, corrosion-resistant structural section that comes close to the final shape and saves heavy machining. Metline supplies standard and custom 6061 extrusions to drawing, worldwide.
- Alloy
- 6061 (Al-Mg-Si-Cu)
- Tempers
- O, T4, T4511, T6, T6511
- Shapes
- Standard and custom sections
- Specs
- AMS 4150 · AMS 4173 · ASTM B221
Why use 6061 extrusions in aerospace?
Extrusion pushes a heated billet through a shaped die, producing long lengths of a constant cross-section. For a stiffener, rail, frame member or seat-structure part, starting from an extrusion rather than plate can cut machining time and material waste dramatically, because most of the shape is already there.
6061 extrudes well, though more slowly than 6063, and gives more than 30 % higher strength than 6063-T6 once aged. It welds easily, anodises evenly and resists corrosion without cladding. That is why it is widely used for secondary structure, interiors, cargo systems, ground equipment and spacecraft frames, while primary wing and fuselage stringers usually use 2024, 7075, 7150 or aluminium-lithium extrusions.
Aerospace 6061 extrusions are made and certified to aerospace specifications with full lot traceability. The chemistry and basic strength levels are those of standard 6061; the specification adds control of tests, tolerances, marking and documentation.
Specifications for 6061 extrusions
| Specification | Scope | Temper |
|---|---|---|
| SAE AMS 4160 | Extruded bar, rod, profiles and tube, annealed | O |
| SAE AMS 4161 | Extruded bar, rod, profiles and tube, solution treated and naturally aged | T4 |
| SAE AMS 4150 | Extruded bar, rod, wire, profiles, tube and flash-welded rings | T6 |
| SAE AMS 4173 | Extruded profiles, stress-relieved by stretching (and straightened) | T6510, T6511 |
| AMS-QQ-A-200/8 | Former federal specification for 6061 extruded bar, rod and shapes | O, T4, T6, T6510, T6511 |
| ASTM B221 / B221M | Commercial extruded bar, rod, wire, profiles and tube | All standard tempers |
| EN 755-2 / EN 755-9 | European extruded profiles: properties and shape tolerances | T4, T6 |
6061 chemical composition (wt %)
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | 0.40 | 0.80 | Forms the strengthening Mg2Si phase with magnesium |
| Iron (Fe) | — | 0.70 | Impurity; held low for toughness and surface quality |
| Copper (Cu) | 0.15 | 0.40 | Adds strength; a small penalty in corrosion resistance |
| Manganese (Mn) | — | 0.15 | Grain structure control |
| Magnesium (Mg) | 0.80 | 1.20 | Main strengthening element with silicon |
| Chromium (Cr) | 0.04 | 0.35 | Limits recrystallisation, improves stress-corrosion resistance |
| Zinc (Zn) | — | 0.25 | Impurity |
| Titanium (Ti) | — | 0.15 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 95.8 – 98.6 % |
Mechanical properties of 6061 extrusions
Minimum values below summarise ASTM B221 and the AMS extrusion specifications. Typical values are for comparison; design to the minimums for your section thickness.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation (min) |
|---|---|---|---|
| O (max) | ≤ 150 MPa / 22 ksi | ≤ 110 MPa / 16 ksi | 16 % |
| T4 / T4511 (min) | 180 MPa / 26 ksi | 110 MPa / 16 ksi | 16 % |
| T6 / T6510 / T6511 (min) | 260 MPa / 38 ksi | 240 MPa / 35 ksi | 8 – 10 % (by thickness) |
| T6, typical | 310 MPa / 45 ksi | 276 MPa / 40 ksi | 12 % |
The density of 6061 is 2.70 g/cm³. Figures of 2.77 g/cm³ sometimes quoted for 6061 profiles are too high and would overstate weight by about 2.5 %.
Physical properties of 6061 (T6)
- Density
- 2.70 g/cm³ (0.0975 lb/in³)
- Modulus of elasticity
- 68.9 GPa (10,000 ksi)
- Thermal conductivity
- 167 W/m·K
- Electrical conductivity
- About 43 % IACS
- Coefficient of thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- 582 – 652 °C
Which extrusion temper to order
T6511
Stretched 1 – 3 % after quenching and minor straightening allowed. The usual choice for sections that will be machined, because they move less.
T6510
Stretched but not straightened afterwards. Specified where straightening marks or residual stress from straightening are unwanted.
T4 / T4511
Naturally aged for forming: stretch-forming, bending into frames, then ageing to T6.
O
Annealed, for severe forming followed by full heat treatment.
6061 profile shapes and sizes
Standard shapes cover most structural needs; custom dies are made for sections that save weight or machining. Typical families:
| Shape | Typical aerospace use | Notes |
|---|---|---|
| Equal and unequal angles | Stiffeners, brackets, frame members | Sharp or radiused corners |
| Channels and U-sections | Floor beams in light aircraft, rails, edge members | American standard and custom proportions |
| Tees and I-sections | Beams, stiffeners, seat and cargo structure | Symmetric sections straighten well |
| Z-sections and hat sections | Stringers and stiffeners in light structures | Often formed in T4 then aged |
| J, F and G sections | Panel edges, trim and closure members | Usually custom dies |
| Hollow and multi-void profiles | Frames, rails, drone booms, heat sinks | Porthole dies; seamless where specified |
| Flat, square and hex bar | Machining stock | Extruded T6511 |
Supply range
- Section size
- Small sections from a few millimetres; larger sections by enquiry with the drawing
- Wall thickness
- From about 1 mm, depending on section size and shape
- Lengths
- Typically 3 – 6 m; cut lengths and machined parts to order
- Finish
- Mill finish, anodised (Type II or III), conversion coated or primed
Tolerances, testing and design tips
Cross-section, straightness, twist and flatness tolerances for AMS and ASTM orders follow ANSI H35.2; EN orders follow EN 755-9. Tighter tolerances can be agreed for critical dimensions, usually with machining allowance on the drawing.
- Keep wall thickness as uniform as possible; sharp changes in thickness cause uneven flow and distortion
- Use generous internal radii (0.5 mm or more) to help metal flow and reduce stress concentration
- Mark critical dimensions and datum faces so the die maker and inspector work to the same features
- Order T6511 for sections that will be machined; T6 sections can bow when one side is cut away
- State whether hollow sections must be seamless; porthole extrusions contain solid-state weld lines
Each lot is tested for tensile properties and dimensions, and supplied with an EN 10204 3.1 certificate. Ultrasonic inspection, hardness and conductivity checks can be added when the drawing requires them.
Where 6061 extrusions are used
- Cabin interiors: seat frames, galley and lavatory structures, overhead bin supports
- Cargo systems: rails, roller trays, restraint structure and container frames
- Light aircraft and UAV structure: stiffeners, frames, longerons and booms
- Spacecraft: frames, rails, brackets and thermal-control hardware
- Ground-support equipment: maintenance platforms, stairs, stands and tooling frames
- Avionics: rack rails, enclosures and extruded heat sinks
How to order 6061 aerospace profiles
- SpecifyAlloy and temper, section drawing or standard shape, length, quantity and the governing specification with its revision (for example AMS 4150, AMS 4173 or ASTM B221).
- ConfirmWe confirm the specification can be met, the tolerance class, any extra tests and the delivery terms (EXW, FOB, CIF or DAP).
- InspectMaterial is checked for dimensions, surface condition and identification; tests named on the order are carried out or arranged with a third party.
- DocumentEach lot ships with a mill test certificate to EN 10204 3.1 showing chemistry and mechanical results, traceable to the cast or lot number.
- Pack and shipExport packing in sealed, moisture-protected wooden cases or on pallets, shipped by sea or air to your port or door.
References and standards
- SAE AMS 4150 – Aluminum Alloy Extrusions, 6061-T6
- SAE AMS 4173 – Aluminum Alloy Extrusions, 6061-T6510 / T6511
- ASTM B221 – Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products (The Aluminum Association)
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
6061 aerospace aluminium (aluminum) extrusions: frequently asked questions
Which AMS specification covers 6061-T6 extrusions?
AMS 4150 covers 6061-T6 extruded bar, rod, wire, profiles and tube. AMS 4173 covers the stretched T6510 and T6511 tempers, AMS 4161 covers T4 and AMS 4160 covers O.
What is the difference between 6061-T6 and T6511 extrusions?
Strength is the same. T6511 is stretched after quenching to relieve stress and may be lightly straightened, so it stays straighter and moves less when machined.
Is 6061 or 6063 better for aerospace profiles?
6061 is stronger and is preferred for structural and machined parts. 6063 extrudes more easily with a better surface and suits trim and lightly loaded sections.
Can you make custom 6061 profiles?
Yes. Send a section drawing; a die is made for the shape and first articles are inspected against the drawing before production.
How strong are 6061-T6 extrusions?
Specified minimums are about 260 MPa tensile and 240 MPa yield; typical values are about 310 MPa and 276 MPa.
Do you supply anodised 6061 profiles?
Yes. Profiles can be supplied mill finish, anodised, conversion coated or primed, cut to length, with certificates, to customers worldwide.
Need 6061 extrusions to an aerospace specification?
Send the section, temper, length, quantity and specification. Our team will reply with tooling, testing and a delivered price.
