T4
Naturally aged and soft. Use it for profiles that will be stretch-bent or roll-formed into tight curves, then artificially aged to T5/T6 strength after forming.
Bright-trim extrusion alloy
6463 T4 / T5 / T6 Automotive Aluminium Profiles
6463 is the bright-trim version of 6063: the same magnesium-silicon strengthening, but with iron held to 0.15 % or less so that chemically or electrolytically brightened and anodised surfaces look almost mirror-like. Vehicle makers use it for window surrounds, roof rails, grille bars, badges and interior trim. Metline supplies 6463 profiles in T4, T5 and T6, mill finish or bright-anodised, to customers worldwide.
- Alloy
- 6463 (EN AW-6463, UNS A96463)
- Tempers
- T4, T5, T6
- Key feature
- Fe ≤ 0.15 % for bright finish
- Standards
- ASTM B221 · EN 755 · EN 573-3
Why 6463 is the trim alloy
The brightness of an anodised aluminium surface depends on how many intermetallic particles sit in the metal. Iron-rich particles scatter light and leave a grey, cloudy film after anodising. 6463 limits iron to 0.15 % (6063 allows 0.35 %) and keeps copper and manganese low, so after mechanical polishing, chemical or electrolytic brightening and a thin clear anodic film the surface reflects light with high specular gloss.
Mechanically, 6463 behaves almost exactly like 6063. It extrudes easily into thin, intricate open and hollow shapes, can be stretch-bent around roof and window curves, and reaches about 240 MPa tensile strength in T6. That is ample for trim that carries little load but must stay straight and dent-free.
Because the bright finish depends on chemistry, surface handling and anodising practice together, 6463 is usually ordered with a finishing specification: gloss level, film thickness, colour and the faces that are visible on the vehicle.
6463 chemical composition (wt %)
| Element | 6463 | 6063 (for comparison) |
|---|---|---|
| Silicon (Si) | 0.20 – 0.6 | 0.20 – 0.6 |
| Iron (Fe) | 0.15 max | 0.35 max |
| Copper (Cu) | 0.20 max | 0.10 max |
| Manganese (Mn) | 0.05 max | 0.10 max |
| Magnesium (Mg) | 0.45 – 0.9 | 0.45 – 0.9 |
| Chromium (Cr) | — | 0.10 max |
| Zinc (Zn) | 0.05 max | 0.10 max |
| Others, each / total | 0.05 / 0.15 | 0.05 / 0.15 |
| Aluminium (Al) | Remainder | Remainder |
Values per the Aluminum Association registration and EN 573-3. A related European variant, 6463A, has slightly different impurity limits; confirm which one your drawing specifies.
Mechanical properties by temper
Typical values describe usual production; specified minimums are what the order standard guarantees. Minimums below are the ASTM B221 values for thin sections; EN 755-2 values are similar.
| Temper | Typical tensile | Typical yield | Typical elongation | Specified minimum (Rm / Rp0.2) |
|---|---|---|---|---|
| T4 | about 150 MPa | about 90 MPa | 20 %+ | about 130 / 70 MPa |
| T5 | about 185 MPa | about 145 MPa | 12 % | 150 / 110 MPa |
| T6 | about 240 MPa | about 215 MPa | 12 % | 205 / 170 MPa |
Physical properties (T6, typical)
- Density
- 2.69 – 2.70 g/cm³
- Modulus of elasticity
- about 69 GPa
- Thermal conductivity
- about 200 W/m·K
- Electrical conductivity
- about 53 – 55 % IACS
- Melting range
- about 615 – 655 °C
Choosing T4, T5 or T6
T5
Press-quenched and aged. The most economical choice for straight or gently curved trim; strength is ample for decorative parts.
T6
Fully solution-treated and aged for maximum strength and dent resistance, for roof rails, bars and parts carrying some load.
How bright automotive trim is finished
- Extrude with surface careClean dies, controlled exit temperature and soft handling avoid die lines and pick-up that would show through the bright finish.
- PolishVisible faces are mechanically polished or buffed where the design calls for a mirror look.
- BrightenChemical brightening (phosphoric-nitric baths) or electropolishing levels the surface on a microscopic scale.
- AnodiseA thin clear anodic film, often 5 – 10 µm for maximum brightness, or thicker films where exterior durability matters more than gloss.
- Seal and protectHot-water or cold seal, then protective film or interleaving for transport.
Satin (etched), brushed and black or bronze anodised finishes are also common on 6463, and many vehicles now use painted or e-coated profiles for a dark trim look.
Supply range and quality checks
Typical supply range
- Shapes
- Custom trim sections, bars, channels, small hollows, plus standard tube, angle, T and U profiles
- Wall thickness
- From about 1 mm for small trim sections
- Length
- Mill lengths or cut and bent parts to drawing
- Finish
- Mill, bright anodised, satin anodised, coloured anodised, e-coat, painted
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. For trim, cosmetic acceptance criteria such as gloss, colour and allowable marks per visible face should be agreed with boundary samples.
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
Where 6463 is used in vehicles
- Window and belt-line trim: bright or black-anodised mouldings around side glass
- Roof rails and cross bars: T6 profiles with anodised or painted finishes
- Grilles and badges: bright bars and frames
- Interior trim: door, dashboard and console inlays, sill plates
- Lighting: reflector and lamp bezel sections where brightness matters
6463 is not used for wheels, suspension arms or engine parts; those need cast or forged alloys with far higher strength.
How to order 6463 profiles
- SpecifyAlloy and temper (e.g. 6463-T5), section drawing marking visible faces, finish, gloss and film thickness, lengths and volume.
- Confirm the standardASTM B221 or EN 755-2 / EN 755-9 for the extrusion, plus your finishing specification.
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your plant or port.
- Process and inspectProfiles are finished, checked against boundary samples, protected with film or interleaving and packed in rigid cases.
- 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)
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- 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
- ISO 7599 – Anodizing of aluminium and its alloys: method for specifying decorative and protective anodic oxidation coatings
6463 automotive aluminium (aluminum) profiles: frequently asked questions
What is the difference between 6463 and 6063?
The main difference is iron: 6463 allows 0.15 % maximum against 0.35 % for 6063. Lower iron means fewer particles to cloud the anodic film, so 6463 can be brightened to a near-mirror finish. Strength is essentially the same.
Which temper should I order for curved trim?
T4 for tight stretch-bends, followed by artificial ageing; T5 for straight or gently curved parts.
How thick should the anodic film be on exterior trim?
Thin films (about 5 – 10 µm) give the brightest look; thicker films (15 – 20 µm or more) last longer outdoors. Many programmes balance the two with a medium film and a high-quality seal.
Is 6463 strong enough for roof rails?
In T6 (about 240 MPa typical tensile) it is used for roof rails and bars with appropriate section design. Highly loaded carrier systems may need 6061 or 6082.
Do you supply finished 6463 trim worldwide?
Yes. Metline supplies mill-finish or finished 6463 profiles worldwide with certificates and protective export packing.
Need bright trim profiles?
Send the section drawing, temper and finish requirements. We will reply with feasibility, certification and delivered pricing.
