Cutting and machining
Saw with carbide-tipped blades and a lubricant; 6061-T6 and 6082-T6 machine cleanly, 6063 is softer and can burr. Support thin flanges close to the cut to avoid chatter.
Extruded structural sections
Aluminium Channel (C, U and Structural Channel)
Aluminium channel is an extruded section with a flat web and two flanges on the same side, sold as structural (Aluminum Association) channel, square-cornered U channel and custom C sections. The usual grades are 6061-T6 for load-bearing work, 6063-T5/T6 for trim and frames, and 6082-T6 in Europe and India. Metline supplies all three in standard and custom sizes, cut to length and certified, to customers worldwide.
- Grades
- 6061, 6063, 6082, 6005A
- Tempers
- T5, T6, T6511, H112
- Standards
- ASTM B221 · B308 · EN 755
- Lengths
- Mill lengths or cut to size
What is aluminium channel?
A channel is the extruded equivalent of a folded sheet edge: one web and two flanges forming a "C" or "U". Because the shape is pushed through a steel die rather than bent, the corners can be thickened, the flanges tapered and the root radii controlled, which gives far better stiffness per kilogram than a press-braked strip of the same weight.
Buyers usually mean one of three things when they ask for channel. Structural channel (often called AA or Aluminum Association channel) has slightly tapered or thickened flanges and filleted roots, and its section properties are published in the Aluminum Association design manual (ADM) so engineers can use it directly in calculations. U channel (also called square-corner or architectural channel) has parallel flanges of uniform thickness and sharp or small-radius inside corners; it is used for edge trims, glazing, sliding tracks and light frames. Custom C sections add lips, ribs, screw ports or T-slots to suit one design.
Aluminium channel weighs roughly one third of a steel channel of the same dimensions, does not rust, needs no painting in most atmospheres and can be anodised or powder coated. Its lower elastic modulus (about 69 GPa against 200 GPa for steel) means an aluminium channel deflects about three times as much under the same load, so structural sections are normally deeper or thicker than the steel parts they replace.
Alloys and tempers used for aluminium channel
Almost all channel is extruded from 6xxx alloys, because magnesium-silicon alloys extrude fast, quench at the press and reach full strength after a short ageing treatment. The values below are specified minimums from ASTM B221 and EN 755-2 for the wall-thickness bands noted; thicker walls can have lower minimums. Your mill certificate shows the actual tested values for the lot.
| Alloy and temper | Tensile strength, min. | Yield strength (0.2 %), min. | Typical use |
|---|---|---|---|
| 6063-T5 (wall ≤ 12.5 mm) | 150 MPa / 22 ksi | 110 MPa / 16 ksi | Architectural and trim sections, anodised profiles |
| 6063-T6 (wall ≤ 3.2 mm) | 205 MPa / 30 ksi | 170 MPa / 25 ksi | Frames and lightly loaded sections that still need a fine finish |
| 6060-T66 (EN, wall ≤ 3 mm) | 215 MPa | 160 MPa | European window, door and façade systems |
| 6005A-T6 (wall ≤ 5 mm) | 270 MPa | 225 MPa | Thin-walled structural and transport profiles |
| 6061-T6 / T6511 | 260 MPa / 38 ksi | 240 MPa / 35 ksi | General structural channels, beams, frames |
| 6082-T6 (wall 5 – 25 mm) | 310 MPa | 260 MPa | Heavier structural sections, Europe and India |
| 7075-T6 / T6511 | 540 MPa / 78 ksi | 483 MPa / 70 ksi | High-stress sections where weldability is not needed |
Typical (not minimum) values for 6061-T6 extrusions are about 310 MPa tensile and 276 MPa yield. Design to the specified minimum, not the typical value.
Physical properties (6061-T6, for comparison)
- Density
- 2.70 g/cm³; 6063 is 2.69 g/cm³
- Modulus of elasticity
- About 69 GPa (10,000 ksi)
- Thermal expansion
- 23.4 – 23.6 µm/m·°C (20 – 100 °C)
- Thermal conductivity
- 167 W/m·K (6061-T6); about 200 W/m·K (6063-T5)
- Electrical conductivity
- 43 % IACS (6061-T6); 53 – 55 % IACS (6063-T5/T6)
Standard aluminium channel sizes and weights
The table lists common Aluminum Association structural channels in 6061-T6. Sizes are depth × flange width × web thickness; flange thickness is greater than web thickness on these sections. Metric weights are converted from the published lb/ft values.
| Size (in) | Size (mm) | Weight (lb/ft) | Weight (kg/m) |
|---|---|---|---|
| 3 × 1.50 × 0.13 | 76.2 × 38.1 × 3.3 | 1.135 | 1.69 |
| 3 × 1.75 × 0.17 | 76.2 × 44.5 × 4.3 | 1.597 | 2.38 |
| 4 × 2.00 × 0.15 | 101.6 × 50.8 × 3.8 | 1.738 | 2.59 |
| 4 × 2.25 × 0.19 | 101.6 × 57.2 × 4.8 | 2.331 | 3.47 |
| 5 × 2.25 × 0.15 | 127.0 × 57.2 × 3.8 | 2.212 | 3.29 |
| 6 × 2.50 × 0.17 | 152.4 × 63.5 × 4.3 | 2.834 | 4.22 |
| 6 × 3.25 × 0.21 | 152.4 × 82.6 × 5.3 | 4.030 | 6.00 |
| 8 × 3.00 × 0.19 | 203.2 × 76.2 × 4.8 | 4.147 | 6.17 |
| 10 × 3.50 × 0.25 | 254.0 × 88.9 × 6.4 | 6.136 | 9.13 |
| 12 × 4.00 × 0.29 | 304.8 × 101.6 × 7.4 | 8.274 | 12.31 |
Typical supply range
- U channel (equal flange)
- From about 10 × 10 × 1.5 mm up to 150 × 75 mm sections; unequal flanges on request
- Structural channel
- 2 in to 12 in (50 – 305 mm) depth in the AA series; metric and IS sections on request
- Lengths
- Standard mill lengths (commonly 3 m, 6 m, or 20 ft / 25 ft), or cut to length
- Finish
- Mill finish, anodised (clear, bronze, black), powder coated, brushed
- Processing
- Saw cutting, punching, drilling and CNC machining to drawing
Exact availability depends on alloy, temper and die; we confirm the section and length with each quotation.
To estimate the weight of a channel that is not listed, multiply its cross-sectional area by the density: one square centimetre of 6061 section weighs 0.27 kg per metre. For U channel with uniform thickness, the area is roughly (web height + 2 × flange width − 2 × thickness) × thickness.
Standards, tolerances and inspection
Channel is ordered to a product standard that fixes chemistry and properties, plus a tolerance standard that fixes dimensions, straightness and twist. Quote both on your purchase order.
| Purpose | North America | Europe / international |
|---|---|---|
| Extruded bar, rod, profiles | ASTM B221 (ASME SB-221) | EN 755-1, EN 755-2 |
| Structural profiles in 6061-T6 | ASTM B308/B308M | EN 755-2 with EN 1999 (Eurocode 9) design |
| Dimensional tolerances | ANSI H35.2 | EN 755-9 (profiles); EN 12020-2 (precision 6060/6063) |
| Chemical composition | Aluminum Association registration | EN 573-3 |
| Structural design | Aluminum Association design manual (ADM) | EN 1999-1-1 |
| Inspection certificate | Mill test report | EN 10204 type 3.1 |
Tolerances for channels depend on the circumscribing circle of the section and on the wall thickness. Precision 6060/6063 profiles for windows and fittings are commonly ordered to EN 12020-2, which is tighter than EN 755-9. For channels that must slide or nest into other parts, mark the critical dimensions on the drawing and agree measuring points with the extruder, because flange tips can spread or close slightly after ageing.
Cutting, welding, bending and finishing
Welding
MIG or TIG with ER4043 or ER5356 filler. The heat-affected zone of 6xxx tempers drops to well below T6 strength, so welded frames are designed to reduced allowables in the ADM or Eurocode 9.
Bending
Channel can be roll-bent the easy way or the hard way, but flanges tend to buckle or flare. Allow larger radii in T6, or bend in T4 and age afterwards.
Anodising
6063 gives the most uniform anodised colour and is preferred for visible trims. 6061 and 6082 anodise well but can look slightly grey or show streaks.
Fastening
Use stainless or aluminium fasteners with isolating washers in wet areas to avoid galvanic corrosion against carbon steel or copper.
Joining to steel
Separate aluminium channel from steel with gaskets, tape or paint when the joint will be wet or salty.
Where aluminium channel is used
- Transport: trailer cross members, truck body frames, bus and rail interiors, ramp edges
- Building and façades: glazing channels, curtain-wall subframes, sunshade supports, cladding rails
- Marine: dock and gangway framing, boat seating and deck structures
- Electrical and solar: cable trays, panel mounting rails, enclosure frames, busbar supports
- Machinery: guards, conveyors, linear guide carriers, equipment skids
- Interiors and furniture: shelving, display systems, shower screens, cabinet and drawer tracks
6061 vs 6063 vs 6082 channel
| Property | 6061-T6 | 6063-T5/T6 | 6082-T6 |
|---|---|---|---|
| Strength | High | Medium | Highest of the three in thick sections |
| Surface finish and anodising | Good | Excellent | Good |
| Section complexity | Moderate | Thin walls, fine detail | Moderate |
| Weldability | Good | Good | Good |
| Typical use | Structural channel (AA series) | U channel, trims, glazing | European and Indian structural sections |
If a channel will be seen and touched, 6063 usually gives the best result. If it carries load, specify 6061-T6 or 6082-T6 and check deflection as well as stress, because stiffness rather than strength often governs aluminium design.
How to order aluminium channel
- SpecifySection (AA designation, dimensions or drawing), alloy and temper, length, quantity, finish and governing standard.
- QuoteWe confirm the die or nearest standard section, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP).
- ProcessCut to length, deburred and finished as ordered; machining or punching on request.
- DocumentMill test certificate to EN 10204 3.1 with chemistry and mechanical results; inspection report on request.
- ShipBundled with interleaving and protective film, packed in export cases or on pallets for sea or air freight.
References and standards
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- ASTM B308/B308M – Aluminum-Alloy 6061-T6 Standard Structural Profiles
- EN 755-2 and EN 755-9 – Extruded rod/bar, tube and profiles: mechanical properties and profile tolerances
- The Aluminum Association – Aluminum Design Manual and Aluminum Standards and Data
- EN 1999-1-1 (Eurocode 9) – Design of aluminium structures
Aluminium (aluminum) channel: frequently asked questions
What is the difference between C channel and U channel?
In everyday use the terms overlap. Structural "C" channel usually has thicker, slightly tapered flanges and filleted inside corners, with published section properties. "U" channel normally has parallel, uniform-thickness flanges and square or small-radius corners, and is used for trims, tracks and light frames.
Which aluminium grade is strongest for channel?
Among common weldable grades, 6082-T6 and 6061-T6 are the strongest, with minimum yield strengths around 240 – 260 MPa. 7075-T6 channel is much stronger but is not suitable for fusion welding and costs more.
How much does aluminium channel weigh?
A 4 × 2 × 0.15 in Aluminum Association channel weighs 1.738 lb/ft (about 2.59 kg/m), and a 6 × 2.5 × 0.17 in channel 2.834 lb/ft (about 4.22 kg/m). For other sections, multiply the cross-sectional area in cm² by 0.27 to get kg per metre.
Can aluminum channel replace steel channel?
Often, but not size for size. Aluminium is about one third the weight of steel and has about one third the stiffness, so a replacement channel is usually deeper or thicker to keep deflection within limits. The weight saving is still typically 40 – 50 %.
Is 6063 channel strong enough for structural use?
6063-T6 is used for light structures such as frames and handrail parts, but its minimum yield is only about 170 MPa. For load-bearing members, specify 6061-T6 or 6082-T6.
Can you supply channel cut to length and anodised?
Yes. Metline supplies channel cut to length, with anodising, powder coating or machining on request, and ships worldwide with a mill test certificate.
Need aluminium channel?
Send the section, grade, length, finish and quantity. We will reply with availability, certification and a delivered price to your port or site.
