T6
Solution treated (at the press or in a furnace), quenched and artificially aged. The standard structural temper for profiles and tube.
Structural extrusion alloy
6061 Aluminium Extrusions & Custom Profiles
6061 is the structural choice among extrusion alloys: about 25 % stronger than 6063 in the T6 temper, weldable, machinable and corrosion resistant. Metline supplies 6061 extruded profiles, structural shapes, bar and tube in T4, T6 and the stretched T6511 temper, to standard dies or your own drawing, certified to ASTM, AMS and EN and shipped worldwide.
- Alloy
- 6061 (Al-Mg-Si-Cu)
- Tempers
- T4, T6, T6511
- Min. strength T6
- 260 MPa tensile
- Standards
- ASTM B221 · EN 755
Why choose 6061 for extrusions?
Extrusion forces a heated billet through a steel die to make a long product with a constant cross-section. 6061 is one of the stronger alloys that can still be extruded economically into hollow and complex shapes, which is why it is specified for load-bearing profiles in machinery, transport and structures.
The alloy gets its strength from magnesium silicide precipitates formed during ageing, helped by a small copper addition. Chromium controls grain structure and improves resistance to stress corrosion. In return for this richer chemistry, 6061 extrudes more slowly than 6063, needs a faster quench at the press to reach full T6 strength, and produces a slightly less bright surface. For thin decorative sections 6063 is the better option; for parts that carry load, 6061 is the safer one.
In North America 6061 is the default structural extrusion grade, and the Aluminum Association standard I-beams, channels and angles are usually supplied in 6061-T6. In Europe the role is more often filled by 6082 or 6005A, which give similar strength; Metline supplies all three so a design can follow the standard used in the destination market.
6061 chemical composition (wt %)
| Element | Min | Max |
|---|---|---|
| Silicon (Si) | 0.40 | 0.80 |
| Iron (Fe) | — | 0.70 |
| Copper (Cu) | 0.15 | 0.40 |
| Manganese (Mn) | — | 0.15 |
| Magnesium (Mg) | 0.80 | 1.20 |
| Chromium (Cr) | 0.04 | 0.35 |
| Zinc (Zn) | — | 0.25 |
| Titanium (Ti) | — | 0.15 |
| Others, each / total | — | 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
Registered Aluminum Association limits, identical to EN 573-3 for EN AW-6061. The actual cast analysis is reported on the mill certificate.
Mechanical properties of 6061 extrusions by temper
Designers should use specified minimums. Typical values are given for comparison and are what the material usually achieves.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation | Basis |
|---|---|---|---|---|
| O | ≤ 150 MPa | ≤ 110 MPa | 16 % min | Specified (annealed, maximum values) |
| T4 / T4511 | 180 MPa min | 110 MPa min | 14 – 16 % min | Specified, ASTM B221 / EN 755-2 |
| T6 / T6511 | 260 MPa min (38 ksi) | 240 MPa min (35 ksi) | 8 – 10 % min (by thickness) | Specified, ASTM B221 / EN 755-2 |
| T6, typical | about 310 MPa (45 ksi) | about 275 MPa (40 ksi) | about 12 % | Typical |
| T6 welded (heat-affected zone) | about 165 MPa (24 ksi) | about 105 MPa (15 ksi) | — | Design value, Aluminum Design Manual |
Physical properties (T6)
- Density
- 2.70 g/cm³
- Elastic modulus
- 68.9 GPa (10,000 ksi)
- Thermal conductivity
- 167 W/m·K
- Electrical conductivity
- about 43 % IACS
- Thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- 582 – 652 °C
Which 6061 extrusion temper to order
T6511
T6 plus a controlled stretch of about 1 – 3 % to relieve quench stress, with minor straightening allowed. Preferred for bar and profiles that will be machined, because parts stay straight.
T6510
Stretched like T6511 but with no straightening after stretching. Used where the specification asks for it.
T4 / T4511
Naturally aged and softer. Bend or form the profile in T4, then age it to T6.
O
Annealed for maximum ductility, for severe forming or bending, followed by full heat treatment.
T5 / T1
Cooled from the press and aged without a separate solution treatment. Lower and less consistent strength than T6; use only where the drawing permits.
Standards and international equivalents
| System | Designation | Extrusion standards |
|---|---|---|
| ASTM / Aluminum Association | 6061 | ASTM B221 (profiles, bar, tube), B241 (seamless pipe and tube), B308 (standard structural shapes), B429 (structural pipe and tube) |
| Aerospace and defence | 6061-T6 / T6511 | AMS 4150 and related AMS specifications; AMS-QQ-A-200/8 |
| UNS | A96061 | — |
| European | EN AW-6061 (AlMg1SiCu) | EN 755-1/-2 (properties), EN 755-9 (profile tolerances), EN 12020 (precision profiles) |
| ISO | AlMg1SiCu | ISO 6362 |
| Japan | A6061S (extruded shapes) | JIS H4100 |
| India | 65032 (formerly HE20) | IS 733, IS 1285 |
The Indian grade is a commonly cross-referenced close equivalent rather than an identical chemistry; confirm the governing standard on your drawing.
Designing a profile in 6061
6061 can be extruded into solid, semi-hollow and hollow shapes, including porthole-die hollows, but it is less forgiving than 6063. Following a few rules keeps die cost down and quality up.
- Wall thickness: keep walls uniform where possible and allow for thicker minimum walls than in 6063, typically from about 1.5 – 2 mm upward depending on profile size
- Circumscribing circle: the smallest circle enclosing the section sets press size and price; compact profiles are cheaper
- Tongue ratio: deep, narrow channels stress the die; keep depth-to-gap ratios moderate or open the gap
- Radii: generous internal corner radii (0.5 mm or more) improve metal flow and fatigue life
- Quench: thick and thin walls in one section cool at different rates; very mixed sections may need a furnace solution treatment for full T6
- Tolerances: standard tolerances follow ASTM B221 / ANSI H35.2 or EN 755-9; call out tighter limits only where function needs them
Our team reviews each drawing for extrudability and suggests changes before a die is made. For a step-by-step design guide see extrusion design and production.
Machining, welding, bending and finishing
Machining
Machines well in T6 and T6511 with sharp carbide tools, high speeds and coolant. T6511 keeps long bars straight as material is removed.
Welding
MIG or TIG with ER4043 or ER5356 filler. The heat-affected zone drops to near T4 strength, so welded frames are designed to reduced stresses or re-heat-treated.
Bending
Limited in T6. For tight bends, bend in T4 or O and then age. Stretch forming and rotary draw bending suit long curved profiles.
Anodising
Takes clear, coloured and hard anodising, though the finish is slightly less bright than 6063. Specify visible faces on the drawing.
Powder coating
Coats well after chromate-free pretreatment; standard for architectural and outdoor equipment.
Corrosion
Good in atmospheric and fresh-water service. In seawater, anodise or coat, or use 5xxx or 6082 for immersed parts.
Where 6061 extrusions are used
- Structures: I-beams, channels, angles and tubes for platforms, walkways, bridges and scaffolding
- Transport: truck bodies, trailer rails, bus frames, rail interior structures and EV battery frames
- Machinery: linear-motion bases, frames, rails and housings that will be machined
- Marine: boat towers, rails and fittings above the waterline
- Sports and leisure: bicycle frames and parts, climbing equipment, outdoor furniture
- Aerospace ground equipment and defence: maintenance stands, shelters and racks
6061 compared with 6063, 6082 and 7075 extrusions
| Property | 6063-T6 | 6061-T6 | 6082-T6 | 7075-T6 |
|---|---|---|---|---|
| Min. tensile (thin walls) | 205 – 215 MPa | 260 MPa | 290 – 310 MPa | about 540 MPa |
| Min. yield (thin walls) | 170 MPa | 240 MPa | 250 – 260 MPa | about 480 MPa |
| Extrudability | Excellent | Good | Good | Poor (simple shapes only) |
| Surface finish | Excellent | Good | Good | Fair |
| Weldability | Good | Good | Good | Not recommended |
| Typical use | Architecture, trims, heat sinks | Structural profiles, machined parts | European structural profiles | Aerospace, highly stressed parts |
Read more in 6061 vs 6063 and 6061 vs 6082.
How to order 6061 extrusions
- SpecifyProfile drawing or standard shape, temper (T6, T6511, T4), length, quantity and governing standard (ASTM B221, EN 755, AMS).
- ReviewWe check extrudability, tolerances and finish, and confirm whether an existing die fits or a new one is needed.
- SampleFor new dies, first-article samples and a dimensional report are supplied for approval.
- Produce and certifyExtruded, heat treated, cut and inspected; EN 10204 3.1 certificate with chemistry and tensile results.
- ShipInterleaved and film-wrapped bundles in export cases, on EXW, FOB, CIF or DAP terms.
References and standards
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- EN 573-3 – Chemical composition and form of wrought products
- The Aluminum Association – Aluminum Design Manual
- ASM International – Properties of Wrought Aluminum and Aluminum Alloys: 6061
6061 aluminium (aluminum) extrusion: frequently asked questions
What is the difference between 6061-T6 and 6061-T6511 extrusions?
Both have the same minimum strength. T6511 has been stretched after quenching to relieve residual stress and may have minor straightening, so it stays straighter when machined. Order T6511 for bar and profiles that will be machined.
Is 6061 or 6063 better for extrusion?
6063 extrudes faster, into thinner walls, with a brighter surface, so it suits architectural and decorative profiles. 6061 is about 25 % stronger and is chosen for load-bearing parts. If the profile carries significant load, use 6061 (or 6082 in Europe).
Can 6061 extrusions be welded?
Yes, with ER4043 or ER5356 filler by MIG or TIG. Expect the heat-affected zone to fall to about 165 MPa tensile, and design welded joints for that reduced strength.
What is the minimum wall thickness for a 6061 extrusion?
It depends on profile size and shape, but 6061 generally needs thicker walls than 6063, often from about 1.5 – 2 mm for small and medium profiles. Send the drawing and we will confirm what can be extruded reliably.
Do you make custom 6061 profiles?
Yes. Metline supplies 6061 profiles from existing dies or from new dies made to your drawing, with samples for approval before production.
Need 6061 extrusions?
Send the drawing, temper, lengths and quantity. We will reply with die details, certification and a delivered price.
