Aluminium Extrusion
The process, and resulting product, of forcing heated aluminium billet through a shaped die to create long profiles used in window frames, structural framing and vehicle components.
Covered in 1 MetalsCost.com News Intelligence article, most recently on August 24, 2026.
Overview
Aluminium extrusion is both a manufacturing process and the resulting product: a heated aluminium billet is pushed through a shaped steel die, so the metal emerges as a continuous length carrying the die's exact cross-section. Unlike rolled sheet, which comes out flat, extrusion can produce complex shapes — hollow tubes, ribbed panels, interlocking channels — in a single pass, which is why it's the default method whenever a part needs a custom profile rather than a flat or simple round form.
How It's Manufactured
A cylindrical billet, usually cast from a 6000-series alloy, is heated until it's plastic but still solid, then loaded into a hydraulic press. A ram forces it through a hardened die machined with the target cross-section, and the metal flows out the other side as a continuous profile. That profile is stretched to remove twist, cut to length, and typically heat-treated, or aged, to reach its rated strength. Hollow profiles need a more complex mandrel-and-die setup than solid shapes, since the die has to form an internal cavity as well as the outer surface.
Byproducts
The main waste stream is the discard butt — the small remnant of billet that can't be pushed through the die — along with trim scrap from cutting profiles to length and material lost during die changeovers. Nearly all of this is aluminium of known alloy composition, so it's readily recycled rather than discarded, and many extrusion plants remelt their own scrap on site in a closed loop. Oxide skin removed during anodizing or other surface finishing is a smaller secondary waste stream, generally handled separately from metallic scrap.
Who Consumes It
Construction is the largest buyer, using extruded aluminium for window and door frames, curtain wall systems and structural framing, valued for its strength-to-weight ratio and corrosion resistance. Transportation manufacturers — automotive, rail and aerospace — are another major consumer, using extrusions for chassis components and crash-management structures as vehicles get lighter to meet efficiency targets. Industrial equipment builders, and companies assembling modular framing for conveyors, enclosures and solar mounting systems, round out the buyer base.
Everyday Uses
Most people encounter aluminium extrusions without noticing: window and door frames, the internal framing inside laptops and appliances, ladder rails, and the mounting rails on rooftop solar panels are all typically extruded aluminium. Curtain rods, furniture legs, and the frames of some bicycles and strollers are common consumer-facing examples, chosen because they're light, rigid and resistant to rust.
Industrial Uses
In construction, extrusions form structural framing, curtain wall mullions and thermal-break window systems. In transportation, extruded aluminium shows up in chassis rails, crash boxes, and increasingly in EV battery enclosures, where its light weight helps offset battery mass. Manufacturers also rely on standardized T-slot aluminium extrusion — familiar from factory automation — to build machine frames, conveyors and workstations quickly without custom welding or fabrication.
