---
title: "Aluminium 6063-T5 vs T6: the difference you can't see but will definitely feel"
description: What's the difference between 6063-T5 and T6 aluminium? It's not the alloy — it's the heat treatment. Find out why T6 delivers superior strength, durability and corrosion resistance in glazing systems.
---
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# 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.
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