6063-T5
Cooled from the extrusion temperature and artificially aged. The standard temper for architectural and decorative flat bar: good finish, consistent dimensions and the lowest cost.
Architectural extrusion grade
6063 Aluminium Flat Bar
6063 aluminium flat bar is an extruded rectangular bar in the alloy known as "architectural aluminium": moderate strength, very smooth surface, excellent anodising response and high thermal and electrical conductivity. It is the right choice for visible trims, frames, heat sinks and electrical flats, and the wrong choice for heavily loaded structural parts. Metline supplies 6063 flat bar in T5 and T6 tempers, cut to length and certified, to customers worldwide.
- Alloy
- 6063 (Al-Mg-Si)
- Tempers
- T5, T6, T4, T52, O
- Process
- Hot extruded
- Standards
- ASTM B221 · EN 755
What is 6063 aluminium flat bar?
6063 is a lean Al-Mg-Si alloy with less magnesium and silicon than 6061 and almost no copper. That chemistry makes it the easiest of all structural alloys to extrude: it flows through a die at high speed, fills sharp corners and leaves a surface so smooth that it can be anodised without polishing.
A flat bar is the simplest extruded shape, a solid rectangle with square or slightly radiused edges. In 6063 it is produced by pushing a preheated billet through a flat die, cooling it at the press exit (air or water) and then ageing it. Because the alloy can be quenched on the press, it reaches the T5 condition without a separate solution heat-treatment furnace, which keeps cost low and dimensional consistency high.
The trade-off is strength. A 6063-T6 flat bar is roughly 25 % weaker than 6061-T6 in tensile strength and about 20 % weaker in yield. For trims, decorative strips, door and window components, ladder treads, heat-spreading plates, electrical earthing and busbar flats, and light frames, that strength is ample, and the better finish and conductivity are worth more than extra megapascals.
6063 chemical composition (wt %)
These are the registered Aluminum Association limits, which ASTM B221 and EN 573-3 (EN AW-6063) share. The mill test certificate supplied with each lot reports the actual cast analysis.
| Element | Minimum | Maximum | What it does |
|---|---|---|---|
| Silicon (Si) | 0.20 | 0.60 | Forms Mg2Si with magnesium; lower than 6061, which helps extrusion speed |
| Iron (Fe) | — | 0.35 | Impurity; kept low for a bright anodised finish |
| Copper (Cu) | — | 0.10 | Kept low for corrosion resistance and anodising colour |
| Manganese (Mn) | — | 0.10 | Impurity |
| Magnesium (Mg) | 0.45 | 0.90 | Main strengthening element with silicon |
| Chromium (Cr) | — | 0.10 | Impurity |
| Zinc (Zn) | — | 0.10 | Impurity |
| Titanium (Ti) | — | 0.10 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 97.5 – 99.4 % |
6063A (EN AW-6063A) is a European variant with slightly higher Fe and Mg limits, giving a little more strength. Specify which one your drawing calls for; they are not automatically interchangeable on certified orders.
Mechanical properties of 6063 flat bar by temper
The first rows are typical values from published handbook data (ASM / Aluminum Association). They show how the material normally behaves but are not guaranteed. The last rows are specified minimums, which vary with thickness and are what designers should use.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation | Brinell hardness |
|---|---|---|---|---|
| O, typical | 90 MPa / 13 ksi | 48 MPa / 7 ksi | — | 25 HB |
| T1, typical | 152 MPa / 22 ksi | 90 MPa / 13 ksi | 20 % | 42 HB |
| T4, typical | 172 MPa / 25 ksi | 90 MPa / 13 ksi | 22 % | — |
| T5, typical | 186 MPa / 27 ksi | 145 MPa / 21 ksi | 12 % | 60 HB |
| T6, typical | 241 MPa / 35 ksi | 214 MPa / 31 ksi | 12 % | 73 HB |
| T5, minimum (ASTM B221, ≤ 12.5 mm) | 152 MPa / 22 ksi | 110 MPa / 16 ksi | 8 % | — |
| T6, minimum (ASTM B221) | 207 MPa / 30 ksi | 172 MPa / 25 ksi | 8 – 10 % | — |
| T6, minimum (EN 755-2 bar) | 215 MPa | 170 MPa | 10 % | — |
Thicker T5 sections cool more slowly at the press and their minimums drop. Always check the band that matches your bar thickness on the certificate.
Physical properties
- Density
- 2.70 g/cm³ (0.097 lb/in³)
- Modulus of elasticity
- 68.9 GPa (10,000 ksi)
- Thermal conductivity
- About 209 W/m·K (T5), 200 W/m·K (T6)
- Electrical conductivity
- About 55 % IACS (T5), 53 % IACS (T6)
- Coefficient of thermal expansion
- 23.4 µm/m·°C (20 – 100 °C)
- Melting range
- About 615 – 655 °C
Which 6063 temper should you order?
6063-T6
Solution heat-treated (or press-quenched with enough cooling to count as solution treatment) and aged. About 30 % stronger than T5; ordered where the bar carries load, such as ladder rungs, handrails and frame members.
6063-T52
Stress-relieved by compression after quenching, then aged. Used where the bar will be machined or cut into short pieces and must stay straight.
6063-T4
Quenched and naturally aged. Soft enough for bending and forming; can be aged to T6 after fabrication.
6063-O
Annealed for maximum ductility: tight bends, coiling and forming operations.
6063-T66 / T64
European and automotive variants with modified strength or formability. Specify the exact standard if your drawing calls for them.
6063 standards and international equivalents
6063 flat bar is normally an extruded product, so it is ordered to an extrusion standard rather than a plate standard. Quote the edition and temper on your purchase order and we certify to it.
| System | Designation | Flat bar standard |
|---|---|---|
| Aluminum Association / ASTM | 6063 | ASTM B221 (extruded bar), ASTM B221M (metric) |
| UNS | A96063 | — |
| European (EN) | EN AW-6063 / EN AW-AlMg0.7Si | EN 755-2 (properties), EN 755-5 (flat bar tolerances), EN 573-3 |
| German Werkstoff | 3.3206 | DIN EN 755 |
| ISO | AlMg0.7Si | ISO 6362 |
| Japan (JIS) | A6063 | JIS H4040 (bar), JIS H4100 (shapes) |
| China (GB) | 6063 | GB/T 3191, GB/T 3190 |
| India (IS) | 63400 (formerly HE9) | IS 733 |
6063 flat bar sizes and weights
Supply range
- Width
- About 10 – 250 mm (wider flats extruded on request or cut from plate)
- Thickness
- About 2 – 50 mm
- Edges
- Square or lightly radiused; full-radius edges on request
- Length
- Mill lengths of 3 – 6 m, or cut to length
- Imperial sizes
- 1/2 – 8 in wide, 1/8 – 2 in thick
- Finish
- Mill finish, anodised (clear or colour), powder coated, brushed
Standard die sizes ship fastest. Non-standard sections may need a new flat die; see our flat bar die size guide.
Weight in kilograms per metre = width (mm) × thickness (mm) × 0.0027. The table covers common sizes; the flat bar weight calculator handles any size.
| Width × thickness (mm) | kg per metre | kg per 6 m length |
|---|---|---|
| 20 × 3 | 0.162 | 0.97 |
| 25 × 5 | 0.338 | 2.02 |
| 30 × 6 | 0.486 | 2.92 |
| 40 × 5 | 0.540 | 3.24 |
| 40 × 10 | 1.080 | 6.48 |
| 50 × 6 | 0.810 | 4.86 |
| 50 × 10 | 1.350 | 8.10 |
| 60 × 8 | 1.296 | 7.78 |
| 75 × 10 | 2.025 | 12.15 |
| 80 × 12 | 2.592 | 15.55 |
| 100 × 10 | 2.700 | 16.20 |
| 100 × 20 | 5.400 | 32.40 |
| 120 × 15 | 4.860 | 29.16 |
| 150 × 20 | 8.100 | 48.60 |
| 200 × 25 | 13.500 | 81.00 |
Tolerances, straightness and surface inspection
Extruded flat bar tolerances depend on width and thickness. For ASTM orders they follow ANSI H35.2 (the tolerance tables referenced in ASTM B221); for EN orders they follow EN 755-5 for rectangular bar. Straightness, twist and flatness are covered in the same tables.
Quality checks
- Dimensions
- Width and thickness measured at both ends of sampled bars; edge radius checked against drawing
- Straightness and twist
- Checked on a surface table to the order standard
- Surface
- Visible faces inspected for die lines, pick-up and scratches; important for anodised work
- Mechanical
- Tensile and hardness results per lot on the mill certificate
- Certification
- EN 10204 3.1 mill test certificate with chemistry and mechanical results
If the bar will be anodised, tell us which faces are visible. Extrusion die lines run lengthwise and are normally acceptable on non-visible faces, but critical decorative faces may need to be specified as "architectural" or "anodising quality" so the extrusion and handling are controlled accordingly.
Machining, welding, bending and finishing
Anodising
The best anodising alloy among the structural grades. Clear anodising gives a uniform silver; colour and bronze finishes match well from lot to lot. Low copper and iron are the reason.
Welding
Welds easily by MIG and TIG with ER4043 or ER5356 filler. The heat-affected zone drops close to the O or T4 level, so welded frames are designed to reduced allowable stresses.
Bending
T5 and T6 bars bend cold around moderate radii, easiest the "easy way" (about the thickness axis). For tight bends, order T4 or O and age afterwards.
Machining
Fair. 6063 is softer and gummier than 6061, so use sharp, polished carbide tools with high rake and good coolant. For heavily machined parts choose 6061 or 6082.
Powder coating
Accepts powder and liquid paints well after chromate or chrome-free conversion pretreatment.
Corrosion
Very good in atmospheric and mildly corrosive conditions, including coastal air when anodised.
Where 6063 flat bar is used
- Architecture: window and door components, glazing beads, cladding trims, balustrade flats, shopfitting
- Thermal management: heat spreaders and simple heat sink bases where conductivity matters more than strength
- Electrical: earthing flats, light busbar and connectors (for main busbar, 6101 is the purpose-made grade)
- Furniture and interiors: frames, edge trims, handles and display systems
- Transport interiors: rails, luggage racks, trim strips in buses and rail coaches
- Access equipment: ladder components, steps, light platforms
- Signage and lighting: LED mounting strips and frames
6063 flat bar compared with 6061, 6082 and 6101
| Property | 6063-T6 | 6061-T6 | 6082-T6 | 6101-T6 |
|---|---|---|---|---|
| Typical tensile strength | 241 MPa | 310 MPa | 310 – 340 MPa | 221 MPa |
| Typical yield strength | 214 MPa | 276 MPa | 260 – 300 MPa | 193 MPa |
| Electrical conductivity | 53 % IACS | 43 % IACS | About 40 – 45 % IACS | 57 % IACS (min.) |
| Anodised appearance | Excellent | Good | Fair–good | Good |
| Machinability | Fair | Very good | Very good | Fair |
| Typical use | Trim, frames, heat sinks | Structural, machined parts | Structural (Europe) | Busbar |
Pick 6061 or 6082 when the flat bar carries significant load or will be heavily machined. Pick 6101 when the bar is a current-carrying conductor and conductivity is specified. Pick 6063 when appearance, conductivity and cost lead. Our 6061 vs 6063 article goes into more detail.
How to order 6063 flat bar
- SpecifyAlloy and temper (6063-T5 or T6), width × thickness, edge form, length, quantity, finish and the governing standard (ASTM B221 or EN 755).
- QuoteWe confirm availability, tolerance class, certification and delivery terms (EXW, FOB, CIF or DAP).
- ProcessBars are cut to length, deburred if required, and interleaved or film-wrapped to protect visible faces.
- DocumentMill test certificate to EN 10204 3.1 and packing list with every shipment; third-party inspection on request.
- ShipBundled in wooden crates or on pallets with export packing, by sea or air.
References and standards
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- EN 755-5 – Extruded rectangular bars: tolerances on dimensions and form
- EN 573-3 – Chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM International – Properties of Wrought Aluminum and Aluminum Alloys: 6063
6063 aluminium (aluminum) flat bar: frequently asked questions
What is the difference between 6063-T5 and 6063-T6 flat bar?
T5 is cooled straight from the extrusion press and then aged; T6 is fully solution treated and aged. T6 is roughly 30 % stronger (typical yield about 214 MPa against 145 MPa), while T5 is cheaper and perfectly adequate for trims and frames.
Is 6063 flat bar strong enough for structural use?
For light structures such as frames, handrails and ladder parts, yes, in T6. For heavily loaded or bolted structural members, 6061-T6 or 6082-T6 give about 25 – 40 % more strength for similar cost.
Can 6063 flat bar be used as a busbar?
It conducts well (about 53 – 55 % IACS) and is often used for earthing flats and light busbar. For main power distribution busbar with a specified conductivity, 6101 is the dedicated grade.
How much does 6063 flat bar weigh?
Multiply width × thickness in millimetres by 0.0027 to get kg per metre. A 50 × 6 mm bar weighs 0.81 kg/m and a 100 × 10 mm bar 2.70 kg/m.
Does 6063 flat bar anodise well?
Yes; it is the reference alloy for decorative anodising because its low copper and iron give a clear, even colour. Tell us which faces are visible so they are protected in handling.
Do you supply 6063 flat bar outside India?
Yes. Metline ships 6063 flat bar worldwide from Mumbai with mill certificates and export packing, on EXW, FOB, CIF or DAP terms.
Need 6063 flat bar?
Send the size, temper, finish, length and quantity. We will reply with availability, certification and a delivered price.
