Aluminum Square Tube - Hollow Extruded Square Profile for Frames and Equipment Racks

Aluminum Square Tube — Hollow Extruded Profile for Frames and Fabrication

An aluminum square tube is a hollow extruded profile with four equal, flat sides and a uniform wall. Because the faces are flat and the corners meet at a right angle, it can be butted against another section, bolted through a face, or clamped in a jig. That is why square tube carries most of the bolted framework in light structures and suits frames built from cut lengths on site.

How the hollow square section is produced

Sections are made by pushing heated aluminium through a steel die, then cooling, stretching and cutting to length. A hollow square is formed either over a mandrel through a porthole die, or as a seamed tube welded along one edge and then sized. The wall runs around all four faces, so the section resists bending in both directions and takes screws on any side. Straightness, twist and corner radius decide whether a finished frame sits square.

Why square rather than round

The flat faces do three useful things. They give a full contact surface for brackets, plates and rivets; they let a saw cut sit flush so two lengths meet cleanly at a corner; and they hold their position without rotating when a bolt is tightened. Round tube is stronger per unit weight in torsion, but a frame loaded mainly in bending rarely needs that.

Typical applications

• Framework and racking for tents, stands and display structures
• Machine guards, enclosures and equipment frames
• Handrails, balustrades and safety barriers
• Workbench legs, trolley frames and shelving uprights
• Windows, doors and light partition profiles

Customization options

Because extrusion is a die-based process, the section is specified before the material is run: outer size, wall thickness, corner radius and alloy temper are fixed by the die and the billet, while cut length is free. Secondary work follows the extrusion — cutting to length, drilling and tapping, milling slots, deburring, bending or welding into a sub-assembly. Surface finish is chosen for the working environment.

Points to confirm before ordering

The order should state the outer size and wall, the alloy and temper if a specific grade is required, the cut length and its tolerance, the quantity, and the surface finish. Where holes or slots are needed, a drawing with the position and diameter of every feature avoids a second operation later. Tolerances on straightness, twist and squareness should be agreed up front.

Summary

The aluminum square tube is a hollow extruded profile combining a light section with four flat faces for fastening. It is produced to a fixed die geometry, then cut and machined to size, and finished as the environment requires.