Aluminium Angle Bar: Sizes, Alloys and How to Specify It

What is aluminium angle bar?

An aluminium angle is a long section shaped like the letter L. It is described by three numbers: leg A, leg B and thickness, for example 50 × 50 × 5 mm or 2 × 2 × 1/4 in. When both legs are the same length it is an equal angle; when they differ it is an unequal angle.

Almost all aluminium angle is made by hot extrusion: a heated billet is pushed through a steel die with an L-shaped opening, cooled, stretched straight and then aged to its final temper. Thin, light angles can also be roll-formed or press-braked from sheet, but those have a large inside radius and lower strength than extruded sections, and are rarely used for structural work.

Angle is popular because it is the simplest open section that resists bending in two directions. Bolted or welded into a frame it stiffens panels, carries shelves, supports equipment and protects edges, while weighing about a third as much as a steel angle of the same size. Aluminium also needs no galvanising or painting for most indoor and many outdoor uses, because its natural oxide film protects it.

Equal, unequal and special angle profiles

As a rule of thumb, choose equal angle unless a fixing detail forces unequal legs, because equal sizes are stocked in more alloys and lengths and usually cost less per kilogram.

Which alloy should your aluminium angle be?

The alloy decides strength, surface quality, corrosion behaviour and price. Values below are minimum specified properties for extruded sections in the stated temper and thickness band; typical values are usually 10 – 20 % higher. Always design to the minimums on the mill certificate.

EN 755-2 minimums depend on wall thickness band; the 6082 range covers walls up to 5 mm and 5 – 25 mm. 7075 limits vary strongly with temper and section size, so they are taken from the governing specification and the mill certificate.

6061-T6 vs 6063-T52: 6061-T6 has about twice the yield strength of 6063-T52, so it is the choice whenever the angle carries real load. 6063 extrudes at higher speeds into sharper, thinner shapes with a smoother surface, anodises more evenly and costs less, so it wins for trim, cladding edges, shopfitting and anything where appearance matters more than strength. If you need more strength in 6063, ask for T6 rather than T52.

For other grades see the alloy-specific guides for 6061 angle, 6063 angle, 2024 angle and 7075 angle.

Aluminium angle sizes and weights (metric and inch)

Metric angle is quoted as A × B × t in millimetres, inch angle as A × B × t in inches (with fractional thickness). Common mill lengths are 3 m, 5 m and 6 m, or 12 ft, 20 ft and 24 ft. The weights below are calculated from the nominal cross-section (A + B − t) × t with aluminium density of 2.70 g/cm³. Real sections with root fillets weigh a few per cent more, so use these figures for estimates and freight planning, and the mill certificate for invoicing.

Typical supply runs from very small 10 × 10 × 1 mm trim angles to 200 × 200 × 16 mm heavy sections, and from 1/2 × 1/2 × 1/16 in architectural angle to 8 × 8 × 1/2 in structural angle. Sizes outside that range, or with unusual leg-to-thickness ratios, need a new die. Our angle die size guide lists the standard metric dimensions in detail.

How strong is an aluminium angle?

There is no single "load rating" for an angle, because capacity depends on how it is loaded, how long the span is and how the ends are fixed. Three checks normally govern:

1. TensionCapacity is roughly section area × allowable stress. A 2 × 2 × 1/4 in 6061-T6 angle has about 0.94 in² of area, so it would yield in pure tension at around 33,000 lb before any safety factor. Bolt holes reduce the net area and must be deducted.
2. BendingAngles are weak in bending compared with channels or tubes of the same weight, and they twist under load because the shear centre sits at the corner. For a short cantilever, the load at first yield is the yield stress times the elastic section modulus divided by the lever arm. For a 1 × 1 × 1/8 in angle this is in the order of 80 lb at a 12 in arm; for 2 × 2 × 1/4 in it is in the order of 700 lb. Apply your code's safety factors to these figures.
3. Compression and bucklingLong angles in compression fail by flexural-torsional buckling well below the yield stress. Thin legs (high leg-to-thickness ratio) can also buckle locally. This is why the Aluminum Design Manual and Eurocode 9 (EN 1999-1-1) treat angles with specific slenderness rules.

Two practical consequences follow. First, aluminium's elastic modulus is about one third of steel's (69 GPa vs 200 GPa), so an aluminium angle of the same size deflects about three times as much; stiffness, not strength, often controls the size you need. Second, welding 6061-T6 or 6063-T6 softens the metal near the weld, so welded joints are designed to reduced strength. For critical structures, size the angle with a qualified engineer using the Aluminum Design Manual or EN 1999.

Cut, drilled, slotted, bent and perforated angle

Surface finishes for aluminium angle

Anodising quality depends heavily on alloy: 6063 gives the most uniform colour, 6061 is good, and 7075 and 2024 tend to look darker or patchy. If several profiles in a project must match in colour, specify the same alloy and, ideally, the same anodising batch.

Where aluminium angle is used

• Construction and framing: secondary frames, lintel supports, brackets, partition framing and cladding sub-structures (6061 or 6063)
• Architectural trim: wall corners, stair nosings, tile trims, edge protection and shopfitting details (6063, anodised or powder coated)
• Industrial equipment: machine guards, racks, conveyor side frames and equipment bases (6061-T6, 6082-T6)
• Solar and outdoor structures: panel mounting rails, cross-bracing and enclosure frames, where corrosion resistance and light weight cut installation time
• Transport: truck bodies, trailer floors and side rails, caravan and bus frames, where weight saving pays back in fuel or payload
• Marine: deck fittings, hatch frames and stiffeners (5083 or 6061, often anodised)
• Aerospace: stringers, clips and stiffeners in 2024 and 7075 to AMS specifications

How to specify and order aluminium angle

1. Define the profileEqual or unequal, A × B × t, and corner type (structural radius or sharp corner). Attach a drawing for anything non-standard.
2. Choose alloy and standardFor example 6061-T6 to ASTM B308, 6063-T52 to ASTM B221, or EN AW-6082-T6 to EN 755-2 with tolerances to EN 755-9.
3. Set length and processingMill lengths or cut lengths, plus drilling, slotting, bending or machining.
4. Select finish and packingMill, anodised or coated; interleaved paper or film for finished surfaces; bundles, crates or wooden cases.
5. Confirm documents and deliveryMill test certificate to EN 10204 3.1, packing list, and terms such as EXW, FOB, CIF or DAP to your port or site.

Metline supplies angle in all common alloys and sizes from its base in Mumbai to buyers worldwide, with cutting and processing on request. For full product data on our standard range, see the aluminium angle product page.

Related profiles, alloys and guides

Aluminium (aluminum) angle bar: frequently asked questions