6063-T5
Cooled from the press and artificially aged. The most common architectural temper: adequate strength with the best surface and lowest cost.
Architectural square hollow section
6063 Aluminium Square Tube
6063 square tube is the economical, good-looking square hollow section used for furniture, partitions, display systems, railings and light frames. It extrudes in thin walls with crisp corners and a smooth surface that anodises or powder coats beautifully. Metline supplies 6063 square tubing in T5 and T6, in metric and imperial sizes, cut to length and finished to order, for buyers worldwide.
- Alloy
- 6063 (Al-Mg-Si)
- Tempers
- T5, T6, T52
- Sizes
- 10 × 10 to 200 × 200 mm
- Finishes
- Mill, anodised, powder coated
What is 6063 square tube?
6063 square tube is a four-sided hollow extrusion in the 6063 alloy, usually aged to T5 or T6. It is chosen when the tube will be seen: its surface is smoother and more uniform than 6061, and it costs less to extrude.
Square tube resists bending equally about both axes and twisting better than an open channel or angle of the same weight. That makes it the natural choice for legs, posts and grid frames where loads come from several directions. In 6063, the trade-off is modest strength: a T5 tube has roughly half the yield strength of 6061-T6, so it suits furniture, partitions, shelving and light frames rather than heavy machine bases.
Because 6063 flows so easily through a die, square tube can be produced with very small sizes (12 – 15 mm across), thin walls of around 1 mm, sharp outside corners for a crisp architectural look, or fully rounded corners for furniture and handrails. Many systems also add a slot or T-groove to one face so panels and connectors can be fixed without drilling.
6063 chemical composition (wt %)
| Element | Min | Max | Effect |
|---|---|---|---|
| Silicon (Si) | 0.20 | 0.60 | Combines with Mg to form Mg2Si |
| Iron (Fe) | — | 0.35 | Kept low for a bright, even anodised finish |
| Copper (Cu) | — | 0.10 | Kept low for corrosion resistance |
| Manganese (Mn) | — | 0.10 | |
| Magnesium (Mg) | 0.45 | 0.90 | Strengthening element with Si |
| Chromium (Cr) | — | 0.10 | |
| Zinc (Zn) | — | 0.10 | |
| Titanium (Ti) | — | 0.10 | Grain refiner |
| Others each / total | — | 0.05 / 0.15 | |
| Aluminium | Remainder |
Mechanical properties of 6063 square tube
Typical values show expected test results; minimums are the guaranteed values of the standard. Most square tube for furniture and display work is supplied in T5.
| Temper / basis | Tensile strength | Yield strength (0.2 %) | Elongation | Hardness |
|---|---|---|---|---|
| O, typical | 90 MPa / 13 ksi | 48 MPa / 7 ksi | 25 % | 25 HB |
| T4, typical | 172 MPa / 25 ksi | 90 MPa / 13 ksi | 22 % | 46 HB |
| 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, ASTM B221 minimum (≤ 12.5 mm) | 150 MPa / 22 ksi | 110 MPa / 16 ksi | 8 % | — |
| T6, ASTM B221 minimum | 205 MPa / 30 ksi | 170 MPa / 25 ksi | 8 % | — |
| T6, EN 755-2 minimum (wall ≤ 10 mm) | 215 MPa | 170 MPa | 8 % | — |
| T66, EN 755-2 minimum (wall ≤ 10 mm) | 245 MPa | 200 MPa | 8 % | — |
Physical properties
- Density
- 2.69 g/cm³
- Elastic modulus
- 68.9 GPa
- Thermal conductivity
- about 200 – 209 W/m·K (T6 / T5)
- Electrical conductivity
- about 53 – 55 % IACS (T6 / T5)
- Thermal expansion
- 23.4 µm/m·°C (20 – 100 °C)
- Melting range
- 615 – 655 °C
6063 tempers for square tube
6063-T6
Fully solution treated and aged, about 30 % stronger than T5. Chosen when the section carries load, such as handrails or wide-span mullions.
6063-T52
Aged to a slightly lower strength than T5 for better bendability and stability; often used for thermal-break and bent sections.
6063-T66
A European higher-strength variant of T6 obtained by tighter process control, listed in EN 755-2.
6063-T4
Naturally aged; easier to bend and stretch-form, then age to T5 or T6.
6063-O
Annealed for maximum formability before final shaping.
Standards and equivalents
| System | Designation | Typical tube standard |
|---|---|---|
| ASTM / Aluminum Association | 6063 | ASTM B221 (extruded), B210 (drawn seamless), B241 (seamless pipe), B429 (structural) |
| UNS | A96063 | — |
| Europe | EN AW-6063 (AlMg0.7Si) | EN 755-2 properties; EN 755-8 / EN 755-9 tolerances; EN 12020 precision profiles |
| Germany | 3.3206 | DIN EN 755 |
| Old British | HE9 | BS 1474 (superseded by EN 755) |
| Japan | A6063 | JIS H4100 (shapes), JIS H4080 (tubes) |
| India | 63400 | IS 733 / IS 1285 |
6063 square tube sizes and weights
Supply range
- Metric sizes
- 10 × 10 mm to about 200 × 200 mm
- Imperial sizes
- 1/2 × 1/2 in to 8 × 8 in, walls 0.050 – 0.250 in
- Wall thickness
- 0.8 – 8 mm
- Length
- 3 m, 5.8 m, 6 m, 12 ft, 20 ft or cut to length
- Finish
- Mill, clear or colour anodised, powder coated, brushed, polished, wood-grain
Weights below assume sharp corners and 2.70 g/cm³. Inch sizes are shown in millimetres (for example 25.4 = 1 in, 50.8 = 2 in).
| Size (mm) | Wall (mm) | kg/m | I (cm⁴) | Z (cm³) |
|---|---|---|---|---|
| 12.7 × 12.7 | 1.2 | 0.149 | 0.12 | 0.19 |
| 15 × 15 | 1.2 | 0.179 | 0.21 | 0.28 |
| 19.05 × 19.05 | 1.6 | 0.302 | 0.57 | 0.60 |
| 20 × 20 | 1.5 | 0.300 | 0.64 | 0.64 |
| 25 × 25 | 1.5 | 0.381 | 1.30 | 1.04 |
| 25.4 × 25.4 | 1.6 | 0.411 | 1.44 | 1.14 |
| 30 × 30 | 2 | 0.605 | 2.94 | 1.96 |
| 38.1 × 38.1 | 1.6 | 0.631 | 5.20 | 2.73 |
| 40 × 40 | 2 | 0.821 | 7.34 | 3.67 |
| 50 × 50 | 2 | 1.037 | 14.77 | 5.91 |
| 50.8 × 50.8 | 3.2 | 1.645 | 23.11 | 9.10 |
| 60 × 60 | 3 | 1.847 | 37.14 | 12.38 |
| 75 × 75 | 3 | 2.333 | 74.78 | 19.94 |
| 100 × 100 | 3 | 3.143 | 182.71 | 36.54 |
| 100 × 100 | 5 | 5.130 | 286.58 | 57.32 |
Tolerances and quality control
Square tube to EN orders follows EN 755-9 or the tighter EN 12020-2 for precision architectural sections; ASTM orders follow ANSI H35.2. For furniture and display systems where tubes slot into cast or plastic connectors, the outside size and corner radius matter more than usual, so we recommend stating them as critical dimensions.
Checks on each lot
- Dimensions
- Outside size, wall thickness, corner radius and squareness
- Form
- Straightness, twist and face flatness
- Surface
- Visible-face inspection; protective film or paper interleaving on request
- Finish tests
- Anodic film or powder-coat thickness, adhesion and colour for finished tube
- Certificate
- EN 10204 3.1 mill test certificate with chemistry and tensile or hardness results
Finishing and fabrication
Anodising
6063 is the reference alloy for decorative anodising: low iron and copper give a clear, uniform film in natural, bronze, black and champagne colours.
Powder coating
Accepts polyester and PVDF coatings to Qualicoat or AAMA 2603/2604/2605 specifications after chromate or chrome-free pre-treatment.
Welding
TIG and MIG with ER4043 or ER5356. Strength near the weld falls towards O-temper values, so weld at low-stress points.
Bending
Bends more readily than 6061. T5 or T52 tube suits stretch bending and roll bending for curved façades and furniture.
Machining
Softer than 6061 and can be gummy in T5; sharp, polished tools and lubricant give the best finish.
Corrosion
Very good resistance in urban and rural atmospheres, and good in coastal locations when anodised or coated.
Applications of 6063 square tube
- Furniture: chair and table legs, bed frames, outdoor furniture and modular shelving
- Architecture: balustrade posts, fence pickets, pergolas, screens and louvres
- Interiors: partition frames, ceiling suspension, shop and office fit-out
- Exhibition and retail: display stands, poster frames and modular booths
- Light engineering: machine guards, enclosures, solar frames and light trolleys
- Lighting and electronics: LED housings and equipment racks where conductivity and finish both matter
6063 square tube vs 6061 and 6060
| 6063-T5 | 6063-T6 | 6061-T6 | 6060-T5 | |
|---|---|---|---|---|
| Typical yield | 145 MPa | 214 MPa | 276 MPa | about 150 MPa |
| Finish quality | Excellent | Excellent | Good | Excellent |
| Smallest practical sizes | Very small | Very small | Small | Very small |
| Typical use | Furniture, trim | Posts, light frames | Structural frames | European architectural |
For heavier loads see 6061 square tube, which costs a little more but carries about 30 % more load in T6.
How to order 6063 square tube
- SpecifyAlloy and temper (for example 6063-T5, 25 × 25 × 1.5 mm, black anodised), section size and wall thickness, length, quantity and the governing standard (ASTM B221 or EN 755-2). A drawing helps for cut parts.
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- ProcessMaterial is cut to length, de-burred and, if you ask, bent, machined or finished before packing.
- DocumentEach shipment carries a mill test certificate to EN 10204 3.1 with chemistry and tensile results, plus the packing list. Third-party inspection can be arranged.
- ShipBundled with end caps and interleaving or packed in seaworthy wooden cases, then shipped 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, tubes and profiles: mechanical properties (with EN 755-7 / -8 / -9 dimensional tolerances)
- EN 573-3 – Aluminium and aluminium alloys: chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- EN 12020-2 – Extruded precision profiles in EN AW-6060 and EN AW-6063: tolerances
6063 square tube: frequently asked questions
What is 6063 square tube used for?
Mostly furniture, partitions, display systems, railings, pergolas and light frames: anywhere the tube is visible and loads are moderate.
How much does a 25 × 25 × 1.5 mm aluminium square tube weigh?
About 0.38 kg per metre with sharp corners (2 × (50 − 3) × 1.5 × 2.70 / 1000).
Is 6063 aluminum square tubing weldable?
Yes, by TIG or MIG with ER4043 or ER5356. The area around the weld softens, so weld at low-stress points or allow for reduced strength.
6063 or 6061 square tube: which should I buy?
Buy 6063 for appearance, finishing and cost; buy 6061-T6 when the tube carries significant structural load.
Can you supply square tube with rounded corners?
Yes. Square tube can be extruded with sharp, small-radius or fully rounded corners; tell us the radius you need.
Need 6063 square tube?
Send size, wall, temper, finish, length and destination, and we will reply with availability and a delivered price.
