Aluminium tube applications: where round and box section are used

Aluminium tube is used wherever a structure needs to be strong, light and corrosion resistant: vehicle frames, railings and balustrades, furniture, marine fittings, machine guards and solar mounting. Its appeal is a high strength-to-weight ratio, a self-protecting oxide layer that survives outdoors uncoated, and a clean surface that takes any finish. Both round tube and square or rectangular box section are used, with the alloy chosen for the job. This guide runs through the main applications and how to match tube to each one.

Round tube and box section

Aluminium tube comes in two broad forms. Round tube gives even strength in every direction and is the natural choice for handrails, frames and anything rolled or bent to a curve. Square and rectangular box section gives flat faces that are easy to bolt, weld and butt together, so it dominates framing, furniture and structural bays. Both are hollow extrusions, which puts the metal where it does most work and gives a stiff section for very little weight. For sizes, wall thicknesses and standards see our guide to aluminium tube and box section.

Why aluminium tube is chosen

Three properties explain the range of uses. Aluminium weighs about a third of what steel does, so a tube frame is far lighter for the same size, which matters in transport and in anything that is lifted or moved. It resists corrosion through its self-healing oxide layer, so it lasts outdoors without the coating steel needs, as our guide to whether aluminium corrodes explains. And it has a smooth surface that anodises or powder coats cleanly, so tube can be both structural and decorative. Light, durable and good looking is a rare combination in one material.

Automotive and transport

Weight is everything in transport, and aluminium tube is used throughout it. Box section forms chassis rails, subframes and space frames in vehicles and trailers, where cutting weight improves payload, range and handling. Round tube goes into roll cages, roof racks, seat frames and crash structures. Trailer and horsebox bodies, motorhome frames and light commercial fit-outs lean on aluminium box section for the same reason: every kilogram saved in the structure is a kilogram of extra load or a lower fuel bill. The corrosion resistance is a bonus on vehicles exposed to road salt.

Construction and architecture

In building work aluminium tube appears wherever a light, durable, finished section is wanted. Round tube forms handrails, balustrades, canopy frames and shopfront framing, while box section builds curtain walling mullions, door and window frames, partition systems and infill structures. Because the tube arrives with a clean surface and can be anodised or powder coated to any colour, it serves as the visible architectural element as well as the structure behind it. Its light weight also speeds installation and reduces the load on the building.

Furniture and interiors

Aluminium tube is a staple of furniture and interior fit-out. Square and round tube frame tables, chairs, shelving, display stands and exhibition systems, giving a slim, modern look that is easy to move and will not rust. Anodised tube in particular offers a hard, integral, metallic finish that resists scuffing on furniture that gets handled, which is one reason designers favour it. Lightweight also means flat-pack and modular furniture that ships cheaply and assembles by hand.

Marine and coastal

Saltwater is punishing, and aluminium tube earns its place on and near the water. Round tube forms guard rails, stanchions, biminis, radar arches and boarding ladders, while box section frames pontoons, gangways and deck structures. The right marine alloy resists chloride corrosion so well that uncoated aluminium can outlast even stainless steel in seawater, at a fraction of the weight, which is decisive on a boat. For most marine tube the structural choice is 6082, which extrudes cleanly and resists saltwater well, while the magnesium bearing 5xxx marine grades such as 5083 and 5754 are the choice for plate and hull work and are supplied as tube to order where constant immersion demands them.

Industrial framing and machinery

On the factory floor aluminium box section builds machine guards, workstation frames, jigs, conveyors and safety enclosures, usually from modular T-slot profiles that bolt together without welding. Round tube serves as rollers, guides, pneumatic cylinder bodies and light shafting. The demountable, reconfigurable nature of bolted aluminium framing suits production lines that change often, and the light weight makes guards and fixtures easy to reposition. It is a clean, non-sparking, easily modified alternative to welded steel framing.

Access, staging and structures

Anywhere a structure has to be carried, raised or rigged, aluminium tube wins on weight. It forms ladders, access towers, scaffolding, staging decks, lighting truss and marquee frames, all of which have to be moved and assembled by hand. The strength-to-weight ratio lets a light section carry a working load, and the corrosion resistance means outdoor event and access gear survives the weather. Round tube dominates here because it couples neatly and bends to curves for truss and frame work.

Solar and outdoor structures

Outdoor structures that must last decades without maintenance are a natural fit for aluminium tube and profile. Solar mounting rails, carports, pergolas and canopy frames all use aluminium sections for their weather resistance and light weight, often paired with stainless fasteners against galvanic corrosion. Our guide to PV mounting systems covers the solar application in detail. Fencing, gates and garden structures use the same logic: a section that goes up once and needs no repainting.

Choosing the alloy for the application

The application sets the alloy, and the 6xxx family covers most tube work.

6060 and 6063 give the cleanest surface for visible, finished tube, 6082 adds strength for load-bearing frames, and the 5xxx marine alloys suit constant saltwater exposure. The full mechanical detail is in our guide to EN AW aluminium alloys. Where the load or environment is demanding, the alloy is named on the specification rather than left to chance.

Finishing tube for its environment

Tube is supplied mill finish for hidden structure, or finished where it is seen or exposed. Powder coating adds a thick coloured barrier in the full RAL range and is the usual choice for architectural and outdoor tube. Aluminium also anodises well, building its oxide into a hard integral finish, with 6063 giving an especially bright anodised result, which is why so much visible tube is anodised. Our guide to anodising versus powder coating sets out when each suits the job.

Aluminium tube from ULAMEX

ULAMEX has supplied aluminium tube and box section since 1988, in the alloys and finishes each application needs.

Specifying aluminium tube for a project? Tell ULAMEX the application, the load and the environment and the desk will advise on alloy, section and finish and return a non-binding quotation. See our guides to aluminium tube and aluminium profiles, and our supply capabilities, or contact the export desk at [email protected] or +48 504 424 761.

Frequently asked questions