Bending
Bumper beams are often sweep-bent in T4 or the as-quenched state and then aged. Stretch-bending gives consistent radii with minimal springback.
Crash-management extrusions
6008 Aluminium Profiles for Automotive Structures
6008 is a 6xxx extrusion alloy with a small vanadium addition, developed for automotive structural and crash-relevant profiles. It extrudes like 6005A, reaches similar or slightly higher strength, and folds progressively under axial crush instead of cracking. Metline supplies 6008 profiles in T4, T6 and agreed overaged tempers to drawing, for bumper systems, crash boxes and body structures worldwide.
- Alloy
- EN AW-6008 (AlSiMgV)
- Tempers
- T4, T6, T7x (overaged)
- Key addition
- Vanadium 0.05 – 0.20 %
- Standards
- EN 755 · EN 573-3
What 6008 is designed to do
A crash box or bumper beam has to absorb a defined amount of energy by folding in a controlled concertina pattern. If the alloy cracks at the fold lines, energy absorption drops sharply and the load on the rest of the structure rises. Standard high-strength 6xxx alloys can crack in this test, especially in thick walls or after full T6 ageing.
6008 addresses this with a vanadium addition of 0.05 – 0.20 %. Vanadium forms fine dispersoid particles that help keep a fibrous, unrecrystallised grain structure through the extrusion and heat treatment. That structure resists the grain-boundary cracking that limits crush performance. The rest of the chemistry is close to 6005A, so 6008 extrudes well in thin-walled, multi-cavity hollows.
Vehicle makers typically specify 6008 for crash-relevant profiles, often in an overaged T7 condition that trades a little yield strength for more ductile folding. Non-crash structural parts may use the same alloy in T6 to keep one alloy across the body structure, which simplifies scrap recycling.
6008 chemical composition (wt %)
Limits per EN 573-3 (EN AW-6008, AlSiMgV), also registered with the Aluminum Association (UNS A96008). Vehicle makers frequently narrow these ranges in their own material standards.
| Element | Minimum | Maximum | Role |
|---|---|---|---|
| Silicon (Si) | 0.50 | 0.9 | Forms Mg2Si with magnesium |
| Magnesium (Mg) | 0.40 | 0.7 | Main strengthening element |
| Vanadium (V) | 0.05 | 0.20 | Dispersoids that control grain structure and crush behaviour |
| Iron (Fe) | — | 0.35 | Impurity |
| Copper (Cu) | — | 0.30 | Adds strength |
| Manganese (Mn) | — | 0.30 | Grain control |
| Chromium (Cr) | — | 0.30 | Grain control |
| Zinc (Zn) | — | 0.20 | |
| Titanium (Ti) | — | 0.10 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder |
The old copper-free chemistry sometimes quoted for 6008 is not the registered alloy; copper is permitted up to 0.30 %.
Mechanical properties of 6008 profiles
Published data vary with wall thickness, section type and the ageing practice chosen by the vehicle maker. The figures below are typical ranges to guide design; the order specification sets the guaranteed minimums.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation | Typical use |
|---|---|---|---|---|
| T4 | about 180 – 210 MPa | about 100 – 130 MPa | 15 % or more | Bending and forming before ageing |
| T6 | about 270 – 290 MPa | about 220 – 250 MPa | about 8 – 10 % | Structural members and sills |
| T7x (overaged) | slightly below T6 | agreed per crash spec | about 10 % or more | Crash boxes and bumper beams |
Physical properties
- Density
- 2.70 g/cm³
- Modulus of elasticity
- about 69 GPa
- Thermal conductivity
- about 190 W/m·K (T6)
- Coefficient of thermal expansion
- about 23.5 µm/m·°C
- Melting range
- about 600 – 650 °C
Crash performance is usually verified by an axial crush test on a short profile length or by a three-point bending test, with acceptance based on fold pattern and crack rating rather than tensile values alone. Ask for these tests on the purchase order if the part is crash-relevant.
6008 profile supply range
6008 profile supply range
- Sections
- Custom open, semi-hollow and hollow (multi-cavity) profiles to drawing
- Standard shapes
- Round, square and rectangular tube, angle, channel, T and flat bar
- Size
- Circumscribing circle from small trim sections up to large structural profiles; wall typically 1.5 mm and up
- Length
- Usually cut 3 – 6 m, or precision cut to part length
- Tempers
- T4, T6, and overaged T7x tempers to your specification
- Surface
- Mill finish, anodised, e-coated or powder coated on request
- Processing
- Precision sawing, CNC machining, punching, bending and stretch-bending on request
- Testing
- Tensile tests per lot; axial crush or bending tests on request
The achievable section depends on the die and the alloy's extrudability; send a drawing so we can confirm wall, tolerance and length.
| Typical section | Size guide | Wall guide |
|---|---|---|
| Round tube | about 25 – 250 mm OD | about 1.5 – 10 mm |
| Square and rectangular tube | about 25 × 25 to 200 × 300 mm | about 1.5 – 8 mm |
| Multi-cavity bumper and crash-box sections | to drawing | about 2 – 4 mm typical |
| Angle, channel and T sections | about 25 – 150 mm legs | about 2 – 10 mm |
Forming, joining and finishing 6008
Heat treatment
Ageing time and temperature decide the balance between strength and crush ductility. Keep the agreed cycle constant from lot to lot.
Welding
MIG and laser welding with 4xxx or 5xxx filler. Crash boxes are commonly welded or bolted to the bumper beam and base plate.
Machining
Cut-outs, slots and holes for towing eyes and sensors are machined or punched after ageing.
Corrosion protection
Good corrosion resistance; parts inside the body are e-coated with the body-in-white.
Mixed-material joints
Use self-piercing rivets, flow-drill screws or bonded joints with insulation where 6008 meets steel.
Where 6008 profiles are used
- Front and rear bumper beams: multi-cavity sections that bend and absorb low-speed impacts
- Crash boxes: axially loaded tubes that fold progressively between beam and longitudinal
- Longitudinal members and sills: energy-absorbing body-structure profiles
- Battery-tray side impact members: profiles protecting EV battery packs
- A- and B-pillar reinforcements: where profiles replace stamped parts
- Subframe members: welded hollow profiles combining stiffness and ductility
A typical front crash-management system uses a stretch-bent 6008 bumper beam joined to two square 6008 crash boxes. In a low-speed impact the crash boxes fold first and can be replaced, protecting the longitudinal members behind them.
6008 compared with 6005A, 6082 and 7003
| Property | 6008 | 6005A | 6082 | 7003 |
|---|---|---|---|---|
| Typical T6 yield | about 220 – 250 MPa | about 240 MPa | about 280 – 300 MPa | about 290 – 320 MPa |
| Crush behaviour | Very good | Good | Fair (thicker walls can crack) | Good with proper ageing |
| Extrudability | Very good | Very good | Fair | Good |
| Stress-corrosion sensitivity | Low | Low | Low | Needs control |
| Typical role | Crash boxes, beams | General structure | Thick structural parts | High-strength beams |
Choose 6008 when crash folding behaviour is the deciding factor and wall thickness is moderate. For higher strength bumper beams, 7xxx alloys such as 7003 are used, with ageing controlled for stress-corrosion resistance.
How to order 6008 profiles
- SpecifyAlloy 6008, temper or ageing practice, section drawing, length, tolerances, crash or bending test requirement and annual volume.
- Confirm the standardEN 755-2 and EN 755-9, EN 573-3, or the vehicle maker's crash-alloy specification.
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your plant or port.
- Process and inspectProfiles are aged to the agreed cycle, cut, checked for dimensions, straightness and twist, and packed with separators.
- 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
- 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
- ASM Handbook, Vol. 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
6008 automotive aluminium profiles: frequently asked questions
Why does 6008 contain vanadium?
Vanadium forms fine dispersoids that help keep a fibrous grain structure after extrusion and heat treatment. That improves the alloy's ability to fold under crush loads without cracking.
Is 6008 stronger than 6005A?
They are similar. Typical T6 yield strengths are close, and both extrude thin-walled hollows well. 6008 is chosen mainly for its crash behaviour rather than for higher strength.
What temper is used for crash boxes?
Often an overaged T7 condition agreed with the vehicle maker. It gives slightly lower yield than T6 but more ductile, crack-free folding.
Can 6008 aluminum profiles be welded?
Yes. MIG and laser welding with 4xxx or 5xxx filler are common. As with other 6xxx alloys, the heat-affected zone loses some strength.
How is crash performance tested?
By axial crush tests on short profile lengths or by three-point bending, rated on fold pattern and cracking. These tests are added to the order when the part is crash-relevant.
Do you ship 6008 profiles internationally?
Yes. Metline supplies 6008 profiles worldwide with EN 10204 3.1 certificates and export packing.
Developing a crash-management system?
Send the profile drawing, ageing practice and test requirement. Our team will reply with feasibility and a delivered price.
