Brightening
Chemical brightening (phosphoric-nitric acid baths) or electrobrightening dissolves surface peaks to produce a mirror-like finish. Low iron and silicon keep the surface free of intermetallic pits.
Bright-trim automotive extrusions
5457 H112 Automotive Aluminium Extrusion Profile
5457 is a high-purity aluminium alloy with about 1 % magnesium and a small manganese addition, designed to be chemically brightened and clear-anodised to a bright, durable finish. As H112 extrusions it is used for vehicle mouldings, window and door frames, bezels and interior accents where appearance comes first and loads are light. Metline supplies 5457 profiles to drawing, worldwide.
- Alloy
- 5457 (high-purity Al-1Mg)
- Temper
- H112 (as extruded)
- Finish
- Bright dip + clear anodise
- Standards
- GB/T 33910 · customer drawing
What is 5457 aluminium?
5457 is one of the classic automotive bright-trim alloys. It combines 0.8 – 1.2 % magnesium and 0.15 – 0.45 % manganese with a very pure aluminium base: iron no more than 0.10 % and silicon no more than 0.08 %. The low impurity level keeps the surface free of light-scattering particles, so the metal brightens to a high reflectivity and holds it under a thin clear anodic film.
Compared with the leaner 5657, the manganese and slightly higher magnesium of 5457 add a little strength and help control grain size, which reduces orange-peel and streaking on formed trim. Compared with 5252, it is softer but brightens to a higher brilliance. It is non-heat-treatable; strength comes from the alloy content and, in rolled tempers, from cold work.
Historically 5457 was used for bright bumper face bars and large trim pieces; today it is found mostly in mouldings, frames and bezels. Extrusions in H112 are used for trim with a profiled cross-section, then cut, bent and finished.
5457 chemical composition (wt %)
Limits follow the Aluminum Association registration for 5457. The certificate for each lot reports the measured analysis.
| Element | Minimum | Maximum | Why it matters |
|---|---|---|---|
| Silicon (Si) | — | 0.08 | Very low for bright finishing |
| Iron (Fe) | — | 0.10 | Very low to avoid haze |
| Copper (Cu) | — | 0.20 | |
| Manganese (Mn) | 0.15 | 0.45 | Grain control, slight strength gain |
| Magnesium (Mg) | 0.8 | 1.2 | Solid-solution strength |
| Zinc (Zn) | — | 0.05 | |
| Vanadium (V) | — | 0.05 | |
| Others, each / total | — | 0.03 / 0.10 | |
| Aluminium (Al) | Remainder | About 97.8 – 99.0 % |
Some product sheets print the manganese range as "0.15 – 0.15" or allow zinc up to 0.25 %; the registered limits are 0.15 – 0.45 % Mn and a much lower zinc maximum.
Mechanical properties
H112 extrusions are used as extruded; their properties are close to the annealed condition and are confirmed per lot. Rolled tempers are shown for comparison.
| Condition | Tensile strength (typical) | Yield strength 0.2 % (typical) | Elongation (typical) |
|---|---|---|---|
| O / H112 extrusion | about 130 MPa | about 50 MPa | about 20 % or more |
| H25 sheet | about 180 MPa | about 160 MPa | about 12 % |
| H28 sheet | about 205 MPa | about 185 MPa | about 6 % |
Higher figures sometimes quoted for 5457 H112 (for example 200 MPa tensile) are above what this alloy normally achieves without cold work; design to the tested minimum on the certificate.
Physical properties (approximate)
- Density
- 2.69 g/cm³
- Melting range
- about 630 – 655 °C
- Thermal conductivity
- about 180 W/m·K
- Electrical conductivity
- about 46 % IACS
- Coefficient of thermal expansion
- about 23.8 µm/m·°C
5457 profile shapes and sizes
Typical supply range for 5457 profiles
- Temper
- H112 (as extruded); O on request
- Section types
- Round, square and rectangular tube; angle, channel, T and I sections; flat bar; hollow and multi-cavity custom profiles to drawing
- Size envelope
- Small trim and tube sections up to large structural profiles; the feasible circumscribing circle and wall depend on the die and press, and are confirmed at quotation
- Wall thickness
- From about 1 mm on small sections; thicker walls on structural shapes
- Length
- Standard 6 m mill lengths; cut-to-length parts and longer lengths on request
- Finish
- Mill finish, anodised, anodised and electrophoretic lacquer, powder coated or wet painted
- Processing
- Precision sawing, punching, CNC machining, bending and deburring to drawing
Bright-trim profiles are drawing-specific. Mark visible faces on the drawing so die design and handling protect them.
Brightening and anodising 5457
Clear anodising
A thin, clear anodic film, typically about 3 – 10 µm for bright trim, protects the brightened surface while preserving reflectivity. Thicker films improve durability but reduce brilliance.
Sealing
Hot-water or nickel-acetate sealing closes the pores of the film for weather and car-wash resistance.
Handling
Bright trim stock is packed with interleaving and protected from scratches, fingerprints and moisture; one handling mark can scrap a visible part.
Tolerances and inspection
Unless the drawing states tighter values, profile dimensions follow the general tolerance tables of the order standard. Automotive programmes often add their own limits on critical features such as mounting faces, wall thickness at crush zones and twist over the part length. For bright trim, agree a limit sample and inspection lighting for surface defects before series supply.
Tolerance and inspection references
- Cross-section tolerances
- EN 755-9 (profiles), ASTM B221 with ANSI H35.2, or GB/T 14846 for orders to Chinese standards
- Straightness and twist
- Per the same tables, or as agreed for long automotive parts
- Surface quality
- Visible faces free of die lines, pick-up and blisters beyond the agreed limit sample
- Mechanical testing
- Tensile test per lot to ISO 6892-1 or ASTM B557; hardness checks on request
- Certification
- EN 10204 3.1 mill test certificate with chemistry and mechanical results
Where 5457 profiles are used
- Exterior mouldings: belt-line, window and side mouldings
- Door and window frames: bright surrounds and channel covers
- Roof racks and rails: bright covers and end caps on light-duty rails
- Interior accents: door-handle surrounds, gear-lever and dashboard trim
- Lamp bezels and reflector frames
5457 is not a structural alloy. Bumper beams, body structure and engine parts use 6xxx, 7xxx or cast alloys; listings that put 5457 in those roles describe historic bright bumper covers at most.
5457 compared with 5657, 5252 and 6463
| Property | 5657 | 5457 | 5252 | 6463 |
|---|---|---|---|---|
| Magnesium (%) | 0.6 – 1.0 | 0.8 – 1.2 | 2.2 – 2.8 | 0.45 – 0.9 |
| Manganese (%) | ≤ 0.03 | 0.15 – 0.45 | ≤ 0.10 | ≤ 0.05 |
| Relative strength | Lowest | Low | Highest (5xxx) | High after T5/T6 |
| Brightness | Highest | Very high | High | Very high |
| Heat-treatable | No | No | No | Yes |
How to order 5457 profiles
- SpecifyAlloy and temper (5457-H112), section drawing with visible faces marked, length, finish specification and annual volume.
- Confirm the standardYour drawing and finish specification, with GB/T 33910 or ASTM B221 / EN 755 as the general reference for dimensions.
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your plant or port.
- Process and inspectProfiles are cut, inspected for dimensions and surface, interleaved and packed to prevent marking.
- 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)
- GB/T 33910-2017 – Aluminium and aluminium alloy extruded profiles for automobiles
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- ISO 7599 – Anodizing of aluminium and its alloys: decorative and protective anodic oxidation coatings
- ASM Handbook Vol. 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
5457 automotive aluminium (aluminum) extrusions: frequently asked questions
What is 5457 aluminium used for?
Bright-anodised vehicle trim: mouldings, frames, bezels and interior accents.
How does 5457 differ from 5657?
5457 adds 0.15 – 0.45 % manganese and slightly more magnesium, giving a little more strength and better grain control; 5657 brightens to a marginally higher brilliance.
Is 5457 strong enough for structural parts?
No. With about 130 MPa typical tensile strength as extruded, it is a trim alloy. Use 6xxx alloys for structural profiles.
Can 5457 be heat treated?
No. It is non-heat-treatable; strength comes from magnesium, manganese and cold work.
What finish is applied to 5457 trim?
Chemical or electrolytic brightening, followed by a thin clear anodic film and sealing.
Do you supply 5457 internationally?
Yes. Metline ships 5457 profiles worldwide from Mumbai with 3.1 certificates and protective export packing.
Need bright-trim profiles in 5457?
Send the drawing, finish and volume. We will reply with feasibility, certification and a delivered price.
