T6
Solution heat-treated (on the press by controlled quenching, or separately) and artificially aged. The standard delivery condition for structural members and housings.
Automotive extrusion alloy
6106 T6 Automotive Aluminium Profiles and Extrusions
6106 is a medium-strength Al-Mg-Si-Mn extrusion alloy (EN AW-6106, AlMgSiMn) that sits between 6063 and 6005A: it extrudes into thin, complex hollow sections almost as easily as 6063 but reaches a guaranteed 250 MPa tensile strength in T6. Vehicle makers use it for frames, rails, seat structures and housings where shape complexity and weight matter more than maximum strength. Metline supplies 6106-T6 profiles to drawing, with finishing and machining, to customers worldwide.
- Alloy
- EN AW-6106 (AlMgSiMn)
- Temper
- T6, also T5 and T4
- Min. strength (T6)
- Rm 250 / Rp0.2 200 MPa
- Standards
- EN 755-2 · EN 573-3 · ASTM B221
What is 6106 aluminium and why is it used in vehicles?
6106 is a 6xxx-series alloy designed for extrusion. Its magnesium and silicon form Mg2Si precipitates during ageing, which gives the strength, while a small manganese addition refines the grain structure and lifts strength above that of 6063 without destroying the alloy's flow through the die. The result is a material that can be pushed through porthole dies into multi-cavity hollows with walls around 1 – 2 mm, yet still meets structural property minimums.
In automotive work that combination is valuable. A single 6106 extrusion can integrate screw ports, clip channels, ribs and closed cells that would otherwise need several stamped steel parts and spot welds. Because the profile cross-section is fixed, part designers move complexity into the die and keep downstream operations to cutting, bending, machining and joining.
6106 is most common in Europe, where it is listed in EN 573-3 and EN 755-2 alongside 6060, 6063 and 6005A. It is less familiar in North America, where engineers usually reach for 6063 or 6061 instead; for export projects we can advise on the closest ASTM-registered substitute.
6106 chemical composition (wt %)
Limits are those registered for EN AW-6106 in EN 573-3. Compared with 6063, the manganese window (0.05 – 0.20 %) and the slightly wider copper allowance are the distinguishing features. Each lot certificate reports the actual cast analysis.
| Element | Minimum | Maximum | Role |
|---|---|---|---|
| Silicon (Si) | 0.30 | 0.60 | Forms Mg2Si with magnesium |
| Iron (Fe) | — | 0.35 | Impurity; kept low for surface quality and ductility |
| Copper (Cu) | — | 0.25 | Adds a little strength |
| Manganese (Mn) | 0.05 | 0.20 | Grain control and modest strengthening |
| Magnesium (Mg) | 0.40 | 0.80 | Main strengthening element with Si |
| Chromium (Cr) | — | 0.20 | Grain structure control |
| Zinc (Zn) | — | 0.10 | Impurity |
| Others, each / total | — | 0.05 / 0.10 | |
| Aluminium (Al) | Remainder |
Mechanical and physical properties of 6106
EN 755-2 specifies 6106 in the T6 temper for profiles up to 10 mm wall. Values below are specified minimums unless marked typical; design to the minimums. T5 and T4 can be produced for parts that will be formed before final ageing, with properties agreed on the order.
| Temper / condition | Tensile strength Rm | Proof strength Rp0.2 | Elongation A / A50 | Hardness |
|---|---|---|---|---|
| T6, wall ≤ 10 mm (EN 755-2 minimum) | 250 MPa | 200 MPa | 8 % / 6 % | about 75 HB |
| T6, typical as delivered | 260 – 290 MPa | 220 – 250 MPa | 10 – 12 % | 80 – 85 HB |
| Heat-affected zone after MIG welding (indicative) | about 50 – 60 % of parent T6 | — | — | — |
Physical properties (T6, typical)
- Density
- 2.70 g/cm³
- Modulus of elasticity
- about 69.5 GPa
- Thermal conductivity
- about 190 W/m·K
- Electrical resistivity
- about 0.035 µΩ·m (around 49 % IACS)
- Coefficient of thermal expansion
- 23.4 µm/m·°C (20 – 100 °C)
- Melting range
- roughly 615 – 655 °C
6106 tempers for automotive parts
T5
Cooled from the press and artificially aged. Suits thin sections where press quenching achieves near-T6 properties at lower cost.
T4
Naturally aged. Softer and more ductile for stretch-bending roof rails and window frames, then aged after forming, often in the paint-bake oven or a separate furnace.
T64 / T66 variants
Under-aged or enhanced tempers can be agreed where a design needs extra bendability or slightly higher strength; specify target values on the drawing.
6106 profile shapes and sizes
Typical supply range
- Profile types
- Open sections, semi-hollows and multi-cavity hollows to customer drawing; standard angles, channels, T, U, round, square and rectangular tubes
- Circumscribing circle
- From about 10 mm up to roughly 500 mm, depending on shape and press size
- Wall thickness
- From about 1 mm for small hollows; structural members commonly 1.5 – 4 mm
- Weight per metre
- From a few tens of grams to well over 10 kg/m
- Length
- Standard 6 m mill lengths, or cut lengths to drawing
- Finish
- Mill, anodised, anodised plus e-coat, powder coated or wet painted
Every custom profile needs a die. Send the cross-section drawing with critical dimensions and we will review extrudability before quoting.
| Standard shape | Typical size range | Typical wall range |
|---|---|---|
| Round tube | 25 – 250 mm OD | 1.5 – 19 mm |
| Square tube | 25 – 200 mm | 1.5 – 12 mm |
| Rectangular tube | 25 × 50 – 200 × 300 mm | 1.5 – 12 mm |
| Angle | 25 × 25 – 200 × 200 mm | 2 – 12 mm |
| T and U (channel) | 25 – 150 mm legs | 2 – 12 mm |
Tolerances, testing and documentation
Automotive profiles are almost always made to a part drawing, and the drawing tolerances override the general tables. Where the drawing is silent, the general tolerance standard of the order applies. Critical dimensions, such as mating faces, screw bosses and crash-relevant wall thicknesses, should be marked so they can be measured on every lot.
Tolerance and inspection framework
- General dimensional tolerances
- EN 755-9 for EN orders; ASTM B221 with ANSI H35.2 tables for ASTM orders; GB/T 14846 where a GB drawing applies
- Straightness and twist
- Per the same standards, or tighter values agreed for long members and parts that go straight into robotic welding
- Wall thickness
- Measured at drawing-defined points; closed hollow sections are checked for eccentricity and die-line quality
- Mechanical testing
- Tensile test per lot to EN ISO 6892-1 or ASTM B557, with hardness (Webster or Brinell) for in-process checks
- Microstructure
- Grain size and recrystallised surface layer checked on request, which matters for crash and bending performance
- Documentation
- EN 10204 3.1 certificate; PPAP-style first-article dimensional report on request for series parts
Joining, forming and finishing 6106
6106 behaves much like 6063 in the workshop. MIG and TIG welding work well with ER4043 (lower crack sensitivity) or ER5356 (higher fillet strength); expect the heat-affected zone to lose a large part of its T6 strength, so place welds in low-stress areas or allow for the reduction in design. Self-piercing rivets, flow-drill screws, adhesive bonding and friction stir welding are all used in mixed-material bodies.
For bending, T4 material or local heating gives tighter radii than T6; stretch-bending is common for roof rails and window frames. Machining is straightforward in T6, producing short chips with sharp carbide tools.
Mill finish
Supplied as extruded and aged, for parts that are welded, bonded or painted later in the body shop or e-coat line.
Anodising
Clear or coloured anodic films for trim, roof rails and visible parts. Film class is specified in micrometres, for example AA15 or AA20 for exterior exposure.
E-coat (electrophoretic paint)
Thin, uniform paint that penetrates hollow sections; often used after anodising for a smooth, durable finish on trim.
Powder coating
Thicker polyester or epoxy layers for chassis brackets, racks and accessories that see stone chipping.
Conversion coating
Chromium-free titanium or zirconium pre-treatment before adhesive bonding or painting, improving bond durability.
Machining and fabrication
Cut-to-length, CNC machining, punching, bending and drilling on request, so profiles arrive ready for assembly.
Where 6106 profiles are used in vehicles
- Seat structures and rails: thin-wall hollow tracks and cross-members
- Roof rails, window and door frames: stretch-bent profiles with a good anodised or painted finish
- Sub-frames for ancillaries: brackets and carriers for batteries, cooling modules and electronics
- Electric drive and electronics housings: finned extrusions for inverters and on-board chargers
- Commercial vehicles and buses: body frames, side-wall profiles, floor and luggage-rack sections
- Rail and trailers: interior structures and side-wall profiles where similar section complexity is needed
6106 is not a primary crash-management alloy. Bumper beams and crash boxes usually use higher-strength or specially processed 6xxx and 7xxx grades; 6106 is chosen where moderate strength and a complex section are the priorities.
6106 compared with 6063, 6005A and 6082
| Property (T6, EN 755-2 minimum, thin wall) | 6063 | 6106 | 6005A | 6082 |
|---|---|---|---|---|
| Tensile strength Rm | 215 MPa | 250 MPa | 270 MPa | 290 MPa |
| Proof strength Rp0.2 | 170 MPa | 200 MPa | 225 MPa | 250 MPa |
| Extrudability (thin, complex hollows) | Excellent | Very good | Good | Fair |
| Anodised appearance | Excellent | Very good | Good | Fair |
| Typical automotive use | Trim, frames | Frames, rails, housings | Structural members | Highly loaded members |
Choose 6106 when 6063 is not quite strong enough but a 6005A or 6082 die would be hard to fill or would leave poor surfaces. Minimum values change with wall thickness band; the certificate shows the band that applies to your section.
How to order 6106 profiles from Metline
- SpecifyAlloy and temper (6106-T6), section drawing with critical dimensions, length, finish, quantity per call-off and annual volume.
- Confirm the standardEN 755-2 / EN 755-9 or your OEM material specification; ASTM B221 or GB/T 33910 references can be added for global programmes.
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your plant or port.
- Process and inspectProfiles are cut, finished as ordered, checked against the drawing and packed with interleaving to protect visible faces.
- Document and shipEach lot ships with an EN 10204 3.1 mill test certificate, lot traceability and a packing list, in seaworthy export packing. Third-party inspection can be arranged on request.
References and standards
- EN 573-3 – Aluminium and aluminium alloys: chemical composition and form of wrought products
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- EN 755-9 – Extruded profiles: tolerances on dimensions and form
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- IATF 16949 – Quality management system requirements for automotive production and relevant service parts organisations
6106 automotive aluminium (aluminum) profiles: frequently asked questions
What is the difference between 6106 and 6063?
6106 adds 0.05 – 0.20 % manganese and allows a little more copper, which raises the T6 minimums from about 215 / 170 MPa (6063) to 250 / 200 MPa while keeping similar extrudability and finish quality.
Is there an ASTM equivalent for 6106?
6106 is registered with the Aluminum Association, but it is rarely called up in ASTM-based North American drawings. 6063 or 6061 are the usual substitutes there, depending on whether finish or strength matters more.
Can 6106-T6 be welded?
Yes. Arc weldability is very good with ER4043 or ER5356 filler. The heat-affected zone loses a significant part of its T6 strength, so welded parts are designed to reduced allowable stresses or re-aged.
Can 6106 be anodised for visible trim?
Yes. Its low iron and moderate alloy content give a clean, even anodised film, close to 6063. For mirror-bright trim, a bright-trim alloy such as 6463 is better.
What wall thickness can 6106 hollows achieve?
Small multi-cavity hollows can be extruded with walls of around 1 – 1.5 mm, depending on section size and shape. We review every drawing for extrudability before quoting.
Do you supply 6106 profiles outside Europe?
Yes. Metline supplies 6106 profiles worldwide from Mumbai with EN 10204 3.1 certificates, export packing and EXW, FOB, CIF or DAP terms.
Need 6106 profiles for a vehicle programme?
Send the section drawing, temper, finish and volume. Our team will reply with feasibility, certification and delivered pricing.
