Aluminium 6063-T5 vs T6: the difference you can't see but will definitely feel
The right heat treatment extends the life of your system, reduces maintenance and ensures long-term structural safety.
Two glazing systems can look identical. Same profile, same alloy, same 6063 designation. But their structural performance can be worlds apart. The key is a single letter: T.
The 6063 alloy is a blend of aluminium, magnesium and silicon — the most widely used alloy in architectural and structural aluminium profiles. It's heat-treatable, easy to work with, and well-suited for welding.
But within that alloy, the treatment applied after extrusion changes everything.
What's the difference between T5 and T6?
Both go through an ageing process to increase hardness. The key difference is in how they're cooled: T5 is cooled with air over several days, while T6 is quenched with water over just a few hours.
That single difference has a real impact on performance:
T6 has a higher yield strength, meaning it can withstand greater stress before deforming. It also offers excellent corrosion resistance and is ideal for anodising — the surface treatment that protects aluminium against oxidation, abrasion and corrosion.
The cost? T6 is slightly more expensive than T5 — but the quality gains are well worth it: longer-lasting structures and safer, more reliable systems.
At Glaxior, every profile we use is 6063-T6 aluminium. Because quality isn't just something you see — it's something you design for.