T6
Solution heat-treated and aged; standard for 6xxx and 7xxx bar.
Long products
Aluminium Square Bar
Aluminium square bar is a solid bar of square cross-section, extruded or cold drawn, used for machined blocks, keys, spacers, frames and fabricated structures. Its useful properties depend on the grade, temper, corner form and tolerance class as much as on the size. Metline supplies square bar in all common grades, sharp or radiused corners, cut to length and certified, to customers worldwide.
- Sizes
- about 5 – 200 mm square
- Routes
- Extruded or cold drawn
- Main grades
- 6061, 6082, 6063, 2011
- Standards
- ASTM B211 · B221 · EN 754-4 · EN 755-4
What is aluminium square bar?
Square bar is specified by the width across flats, the corner condition and the length. Compared with round bar it saves machining time whenever the finished part has flat faces, because two or four sides may need no cutting at all. Compared with plate, it gives a long, straight section without saw-cutting strips from a sheet.
Most square bar is extruded and then heat-treated and stretched. Cold-drawn square bar, made by drawing an extruded section through a square die, offers tighter tolerances, sharper corners and a brighter surface, and is the usual choice for keys, gauge blocks and parts that keep the as-supplied faces. Large squares above about 150 mm may also be sawn from plate or forged.
Corners matter more than most buyers expect. Extruded square bar has small radii at the corners; drawn bar can be supplied with near-sharp corners; and decorative or handling applications sometimes call for full radius corners. Specify the corner if it will show on the finished part or must fit a mating slot.
Square bar grades and typical properties
| Grade and temper | Typical tensile | Typical yield | Strengths | Typical uses |
|---|---|---|---|---|
| 6063-T6 | 241 MPa | 214 MPa | Smooth surface, anodises well | Decorative frames, trim, furniture |
| 6061-T6 / T6511 | 310 MPa | 276 MPa | Balanced strength, machinability, weldability | Machined parts, fixtures, structures |
| 6082-T6 | about 310 MPa (EN 755-2 min.) | about 260 MPa (min.) | European structural standard | Frames, brackets, machined parts |
| 2011-T3 | 379 MPa | 296 MPa | Free-machining | High-volume machined components |
| 2024-T351 | 469 MPa | 324 MPa | High strength, fatigue resistance | Aerospace fittings, high-load parts |
| 7075-T6 / T651 | 572 MPa | 503 MPa | Highest strength | Tooling, aerospace and sports parts |
| 5083-H112 | about 270 MPa (min.) | about 110 MPa (min.) | Seawater resistant, weldable | Marine fittings and structures |
Typical values from Aluminum Association and ASM data; minimums from EN 755-2. Large sections may have lower minimum properties; the mill certificate gives the tested values for your lot.
Square bar tempers
T6511 / T651
Stretched after quenching to reduce residual stress and keep machined parts straight.
T3 / T351
Solution treated, cold worked and naturally aged; used for 2011 and 2024.
T5
Cooled from the extrusion press and aged; economical for 6063 decorative bar.
H112
As-extruded with property minimums; usual for 5083 and other non-heat-treatable bar.
O
Annealed for forming or for subsequent full heat treatment.
Square bar sizes and weight per metre
Supply range
- Extruded
- about 6 – 200 mm across flats
- Cold drawn
- about 5 – 75 mm across flats, tighter tolerance
- Imperial sizes
- 1/4 in to 6 in square
- Corners
- Standard extruded radius, sharp (drawn) or full radius on request
- Lengths
- 3 m, 4 m, 6 m, 12 ft random or fixed; cut pieces
- Processing
- Saw cutting, squaring of ends, milling to finished size
Weight in kg/m = side² × 0.0027, with the side in millimetres (density 2.70 g/cm³). A square bar weighs 27 % more than a round bar of the same width. The bar weight calculator covers every size and grade.
| Side (mm) | kg per metre | kg per 3 m | kg per 6 m |
|---|---|---|---|
| 6 | 0.10 | 0.29 | 0.58 |
| 8 | 0.17 | 0.52 | 1.04 |
| 10 | 0.27 | 0.81 | 1.62 |
| 12 | 0.39 | 1.17 | 2.33 |
| 15 | 0.61 | 1.82 | 3.65 |
| 20 | 1.08 | 3.24 | 6.48 |
| 25 | 1.69 | 5.06 | 10.12 |
| 30 | 2.43 | 7.29 | 14.58 |
| 40 | 4.32 | 12.96 | 25.92 |
| 50 | 6.75 | 20.25 | 40.50 |
| 60 | 9.72 | 29.16 | 58.32 |
| 75 | 15.19 | 45.56 | 91.12 |
| 80 | 17.28 | 51.84 | 103.68 |
| 100 | 27.00 | 81.00 | 162.00 |
| 120 | 38.88 | 116.64 | 233.28 |
| 150 | 60.75 | 182.25 | 364.50 |
| 200 | 108.00 | 324.00 | 648.00 |
Standards, tolerances and inspection
| Standard | Covers |
|---|---|
| ASTM B221 / B221M | Extruded bar, including square, with tolerances per ANSI H35.2 |
| ASTM B211 / B211M | Cold-finished bar, including square |
| EN 755-2 / EN 755-4 | Extruded bar: mechanical properties / square bar tolerances |
| EN 754-2 / EN 754-4 | Cold-drawn bar: mechanical properties / square bar tolerances |
| SAE AMS-QQ-A-200 and AMS 4150 series | Aerospace extruded bar and shapes |
| JIS H4040, GB/T 3191 | Japanese and Chinese bar standards |
Tolerances cover width across flats, twist, straightness, corner radius and squareness of the cross-section. Drawn bar is markedly tighter than extruded. Each lot is checked for size, straightness and surface and supplied with an EN 10204 3.1 certificate; ultrasonic inspection is available for aerospace and critical parts.
Machining, welding and finishing
Machining
Stretched tempers (T651, T6511, T351) stay straight when one face is milled heavily. Leave a skim allowance if the finished faces must be flat and parallel to tighter limits than the bar tolerance.
Welding
6061, 6082, 6063 and 5083 weld well by TIG or MIG. 2011, 2024 and 7075 are not recommended for fusion welding.
Anodising
6063 and 6061 anodise to an even finish; sharp corners anodise more thinly, so a small edge break improves coating durability.
Bending
Square bar bends best in O or T4 temper. Expect corner cracking in T6 at tight radii.
Corrosion
5xxx and 6xxx bar suit outdoor and marine use; protect 2xxx and 7xxx in corrosive environments.
Cutting
Carbide-tipped saws with lubricant give burr-free square cuts; specify end squareness if pieces go straight into fixtures.
Where aluminium square bar is used
- Machined components: manifolds, valve blocks, clamps, brackets, sensor housings
- Machinery: keys, guides, wear strips, spacers, frame members and jig bases
- Transport: vehicle brackets, trailer and body hardware, battery-pack parts
- Architecture and furniture: balusters, frames, trims and decorative elements
- Electrical: earthing bars, terminal blocks and heat spreaders
- Marine: fittings and fabricated structures in 5083 and 6082
How to order square bar from Metline
- SpecifyGrade and temper, size across flats, extruded or drawn, corner style, length, quantity and the governing standard.
- QuoteWe confirm alloy, temper, tolerances, certification, packing and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- ProcessBars are cut to length where ordered, checked for size, twist and straightness, and marked with grade, temper and lot.
- DocumentEach delivery carries a mill test certificate to EN 10204 3.1 with the cast analysis and mechanical results; third-party inspection can be arranged on request.
- ShipBundled, interleaved or crated for export and shipped by sea or air on EXW, FOB, CIF or DAP terms.
References and standards
- ASTM B221 – Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- ASTM B211 – Standard Specification for Aluminum and Aluminum-Alloy Rolled or Cold-Finished Bar, Rod, and Wire
- EN 755-4 / EN 754-4 – Extruded and cold-drawn square bar: tolerances on dimensions and form
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets)
- ASM Handbook, Volume 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
Aluminium (aluminum) square bar: frequently asked questions
How much does aluminium square bar weigh?
Multiply the side in millimetres squared by 0.0027 to get kg per metre. A 25 mm square bar weighs about 1.69 kg/m and a 50 mm square bar about 6.75 kg/m.
Can I get aluminium square bar with sharp corners?
Yes. Cold-drawn square bar can be supplied with near-sharp corners; extruded bar has small standard radii. Full-radius corners are also available. State the corner requirement on the order.
Which grade of square bar is best for machining?
2011-T3 machines fastest; 7075-T651 and 6061-T6511 also machine very well and offer more strength or better weldability. Choose a stretched temper for heavy one-sided machining.
Is 6063 square bar strong enough for structures?
6063-T6 has about 214 MPa typical yield strength, enough for frames, furniture and light structures. For load-bearing structures, 6061-T6 or 6082-T6 is usually specified.
What standards cover aluminium square bar tolerances?
EN 755-4 for extruded and EN 754-4 for cold-drawn square bar, and ASTM B221 and B211 (with ANSI H35.2 tolerances) in North America.
Need aluminium square bar?
Send grade, temper, size, corner style, length and quantity. We will reply with availability, certification and a delivered price.
