Form in T4
Do the bending, flaring or stamping in T4. The alloy naturally ages slowly at room temperature, so form within the agreed shelf life.
Automotive Al-Mg-Si-Cu alloy
6009 Aluminium for Automotive Profiles and Body Parts
6009 is a heat-treatable Al-Mg-Si-Cu alloy introduced for car bodies: formable in the T4 temper, then strengthened by artificial ageing or the paint-bake cycle. It is best known as body sheet, but the same chemistry is extruded into profiles where a part must match 6009 panels or be formed before ageing. Metline supplies 6009 profiles, sheet and blanks in T4 and T6 to drawing, worldwide.
- Alloy
- 6009 (Al-Si-Mg-Cu-Mn)
- Tempers
- T4, T6 and paint-baked
- Forms
- Profiles, sheet, blanks
- T4 typical
- Rm about 230 MPa
What 6009 aluminium is
6009 and its sister alloy 6010 were introduced in the mid-1970s as the first purpose-designed 6xxx automotive body alloys. The idea was simple: deliver the metal soft (T4) so it can be stamped or bent like a 5xxx alloy, and let the heat of the paint oven raise its strength so that the finished part resists denting.
6009 balances its silicon and magnesium with a small copper and manganese addition. Copper speeds up the ageing response, so the alloy gains useful strength in a short bake. Manganese controls grain size and helps formability. Its formability in T4 was compared with 5182 at the time, but without the stretcher-strain marks that make 5xxx sheet unsuitable for visible surfaces.
Today most new outer panels use copper-free 6016 or 6014, or 6022 and 6111 in North America. 6009 remains in use on existing designs, for replacement parts and in profiles and formed brackets that must match the alloy of surrounding parts so that they can be welded together and recycled as one scrap stream. Because 6009 and 6010 are so close in chemistry, scrap from the two does not need to be segregated.
6009 chemical composition (wt %)
Registered limits per the Aluminum Association (Teal Sheets). The mill certificate reports the actual analysis of each lot.
| Element | Minimum | Maximum | Role |
|---|---|---|---|
| Silicon (Si) | 0.6 | 1.0 | Excess silicon above Mg2Si boosts ageing response |
| Magnesium (Mg) | 0.40 | 0.8 | Forms Mg2Si precipitates |
| Copper (Cu) | 0.15 | 0.6 | Accelerates and increases ageing |
| Manganese (Mn) | 0.20 | 0.8 | Grain control and formability |
| Iron (Fe) | — | 0.50 | Impurity |
| Chromium (Cr) | — | 0.10 | |
| Zinc (Zn) | — | 0.25 | |
| Titanium (Ti) | — | 0.10 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 95.7 – 98.7 % |
Some suppliers publish 6009 with manganese up to 1.2 % and chromium capped at 0.05 %. Those figures do not match the registered alloy; order to the limits above or to your OEM specification.
Mechanical and physical properties
Values are typical, not guaranteed minimums. T4 is the delivered condition for forming; strength after the paint bake depends on the bake temperature and time and on any pre-strain from forming.
| Condition | Tensile strength | Yield strength (0.2 %) | Elongation |
|---|---|---|---|
| T4 (as delivered) | about 230 MPa | about 125 MPa | about 25 % |
| After paint bake | higher than T4 | rises noticeably; depends on cycle | slightly lower |
| T6 (full artificial ageing) | highest of the three | highest of the three | about 10 – 12 % |
Physical properties
- Density
- 2.71 g/cm³
- Modulus of elasticity
- about 69 GPa
- Thermal conductivity
- about 170 W/m·K
- Coefficient of thermal expansion
- about 23 µm/m·°C
- Melting range
- about 588 – 650 °C
Older supplier data giving 6009-T4 a yield of 180 MPa or more overstate the alloy; it is designed to be soft in T4. If your part needs high as-delivered yield, specify T6 or choose a stronger extrusion alloy such as 6005A or 6082.
6009 profiles, sheet and blanks
6009 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 for forming, T6 for finished parts, or a customer-specified ageing practice
- Surface
- Mill finish, anodised, e-coated or powder coated on request
- Processing
- Precision sawing, CNC machining, punching, bending and stretch-bending on request
- Sheet
- About 0.8 – 3 mm sheet and blanks in T4 for matching panels
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 (mm) |
|---|---|
| Square tube | about 10 × 10 to 150 × 150 |
| Round tube and bar | about 10 – 150 diameter |
| Rectangular and oval tube | about 10 × 20 to 150 × 200 |
| U, C and T sections | about 10 × 20 to 100 × 200 |
Forming, ageing and joining 6009
Age after forming
A paint-bake cycle gives part of the strength gain. A dedicated ageing cycle gives full T6 strength for structural parts.
Welding
Spot, MIG and laser welding all work. The low iron and controlled copper give good spot weldability compared with 2xxx body alloys.
Hemming
T4 hems well for closure panels; hem before ageing to avoid cracking.
Corrosion
Copper reduces corrosion resistance compared with copper-free 6016, so painted or e-coated finishes are normal.
Machining
Machines well in T6; T4 is softer and can be gummy, so use sharp tools.
Typical 6009 automotive parts
- Body panels and inner panels on programs validated in 6009
- Formed brackets and reinforcements bent in T4 and paint-baked
- Bumper face bars and reinforcements on older designs
- Seat frames and trim structures made from bent tube
- Service and replacement parts matching the original alloy
- Truck cab and trailer parts where formability and moderate strength are needed
6009 compared with 6010, 6016 and 6061
| Property | 6009 | 6010 | 6016 | 6061 |
|---|---|---|---|---|
| Copper | 0.15 – 0.6 % | 0.15 – 0.6 % | 0.20 % max | 0.15 – 0.40 % |
| Typical T4 yield | about 125 MPa | about 170 MPa | about 110 – 120 MPa | about 145 MPa |
| T4 formability | Very good | Good | Very good | Fair |
| Paint-bake response | Good | Good, stronger | Good | Slow |
| Corrosion under paint | Good | Good | Very good | Good |
| Typical role | Panels, formed parts | Stronger panels | Outer skins | Structural extrusions |
Use 6009 where formability matters more than strength; choose 6010 for the same family with higher strength. For new outer-panel work, 6016 is the more usual choice today.
How to order 6009
- SpecifyAlloy 6009, temper (T4 or T6), section drawing or sheet size, length, tolerances and annual volume.
- Confirm the standardASTM B221 (extrusions) or ASTM B209 (sheet), the matching EN product standard, or the vehicle maker's specification.
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your plant or port.
- Process and inspectMaterial is cut, inspected for dimensions and surface, and packed to protect T4 parts from damage before forming.
- 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
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- ASM Handbook, Vol. 2B – 6009 and 6010: Sheet Alloys
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- ASTM B209 – Aluminum and Aluminum-Alloy Sheet and Plate
- SAE Technical Paper 770307 – New 6XXX-Series Alloys for Auto Body Sheet
6009 automotive aluminium: frequently asked questions
Is 6009 a sheet alloy or an extrusion alloy?
It was developed mainly as auto body sheet, but the chemistry can be extruded. Profiles in 6009 are used where parts must match 6009 panels or be formed in T4 before ageing.
How strong is 6009-T4?
Typical T4 values are about 230 MPa tensile strength, 125 MPa yield and 25 % elongation. Strength rises after paint baking or full T6 ageing.
What is the difference between 6009 and 6010?
6010 has more silicon and magnesium, so it is stronger but slightly less formable. Their chemistries are close enough that scrap need not be separated.
Why do some data sheets show different 6009 chemistry?
Several published tables are wrong, for example showing manganese up to 1.2 %. The registered limits are Si 0.6 – 1.0, Mg 0.40 – 0.8, Cu 0.15 – 0.6 and Mn 0.20 – 0.8 %.
Can 6009 aluminum parts be welded?
Yes. Resistance spot, MIG and laser welding are all used. Heat input locally reduces the aged strength, as with other 6xxx alloys.
Need 6009 profiles or panels?
Send the drawing, temper and volume. Our team will reply with availability, certification and a delivered price.
