Strength Data for 6063-T5
6063-T5 aluminum has a typical tensile strength of about 145 to 186 MPa (21,000 to 27,000 psi) and a yield strength of about 110 to 145 MPa (16,000 to 21,000 psi). Yield strength is the critical value for engineers because it marks the stress at which the material begins to deform permanently, while tensile strength marks the ultimate breaking point. Elongation at break is 8 to 12 percent, so the alloy retains useful ductility for basic bending and forming, and Brinell hardness is around 60 HB, which keeps machining, cutting and drilling straightforward with standard industrial tools. Density is 2.70 g per cubic centimeter and thermal conductivity is about 200 W per meter-kelvin.
What the T5 Temper Means
The T5 temper means the aluminum is cooled from an elevated-temperature forming process, such as extrusion, and then artificially aged without additional cold working. In practice, the 6063 billet is heated to roughly 450 to 500 C and pushed through a steel die to create the profile shape. As the hot profile leaves the press it is rapidly cooled by air fans, a step called air quenching, and after cooling to room temperature it is aged in an oven at about 175 to 185 C for several hours. This aging precipitates the magnesium and silicon in the metal lattice, stabilizing the material and locking in its final mechanical strength.
Comparison with Other Alloys
For procurement decisions, 6063-T5 should be compared against the grades it competes with. Typical yield strengths are about 120 MPa for 6063-T5, 160 MPa for 6063-T6, 240 MPa for 6061-T6 and 215 MPa for 5083-H116. The pattern is clear: 6063-T5 is weaker than 6061-T6 and cannot match the seawater corrosion resistance of 5083-H116, but it is much easier to push through complex extrusion dies, which gives smoother walls and more intricate shapes. Where surface quality and extrusion complexity matter more than raw strength, 6063-T5 is the right material.
Why Choose 6063-T5 Profiles
The value of 6063-T5 lies in the balance of moderate strength, aesthetic potential and manufacturing efficiency. In architecture, it is the standard material for commercial window frames, door systems, curtain wall framing, roofing structures and partitions because it can be extruded into complex shapes with tight tolerances and withstands standard wind loads. For decorative profiles and consumer goods, its fine grain structure and low copper content give a perfect response to chemical anodizing, with bright, consistent colors and no dull spots, making it the choice for LED strip housings, furniture frames, shower enclosures and retail shelving. For heat dissipation, the thermal conductivity of about 200 W per meter-kelvin suits industrial motor housings, computer heat sinks and inverter casings.
6063-T5 vs 6063-T6
T5 and T6 start from the same alloy, but the cooling differs. T5 is air-quenched out of the press, while T6 is typically water-quenched, so the faster cooling traps more alloying elements in solid solution before aging and produces higher strength. In practice, T6 reaches a yield strength of about 160 MPa versus about 120 MPa for T5, but T6 is more brittle and prone to cracking if bent, and its surface can show slight distortion. T5 is preferred for appearance and formability, T6 for rigidity and strength. If a profile must be bent or rolled into an arc after extrusion, such as an arched window frame, T5 is the practical choice because T6 will likely crack during bending.
Limitations and Selection Guidance
Engineering limits must be respected. Do not use 6063-T5 for heavy-duty structural applications such as bridge decking, crane booms or truck chassis, where 6061-T6 or 7075-T6 is required, and avoid it for parts under continuous high-frequency vibration because its fatigue resistance is limited. Its softness can also produce stringy chips during high-speed CNC milling. The selection matrix is simple: choose 6063-T5 when the product needs complex shapes, thin walls and flawless anodized surfaces; step up to 6061-T6 when the part is load-bearing or heavily machined; and move to 5083-H116 for submerged seawater and offshore service, where the 6000 series is not appropriate.
FAQ
Is 6063-T5 strong enough for structural use?
It is strong enough for light structural use such as architectural framing, window mullions and furniture supports. For heavy-duty load-bearing applications such as vehicle frames or heavy machinery, 6061-T6 or 7075-T6 must be used.
What is the difference between 6063-T5 and 6063-T6?
The difference is in the cooling process. T5 is air-cooled after extrusion and artificially aged, giving moderate strength and excellent formability. T6 is rapidly water-quenched and aged, giving higher tensile and yield strength but lower ductility, so it is prone to cracking if bent.
Can 6063-T5 be anodized?
Yes. 6063-T5 is one of the best aluminum alloys for anodizing. Its low copper content and fine grain structure produce a smooth, uniform anodic layer with bright, consistent colors, which makes it the top choice for decorative finishes.
Is 6063-T5 easy to weld?
Yes. 6063-T5 welds well with TIG or MIG processes using 4043 or 5356 filler wire. Note that welding heat reduces the strength of the metal in the heat-affected zone, so the weld design should account for the local strength loss.
Can 6063-T5 profiles be bent after extrusion?
Yes. The ductility of the T5 temper allows profiles to be bent or rolled into arcs after extrusion, which is why arched window frames and curved sections are normally produced in T5 rather than T6.
Q: What are the exact strength numbers for 6063-T5?
6063-T5 typically delivers a tensile strength of 145-186 MPa, a yield strength of 110-145 MPa and elongation of 8-12%, with a Brinell hardness around 60 HB; it is a medium-strength alloy suited to light structural and architectural duty.
Q: Where is 6063-T5 commonly used?
6063-T5 is the standard for window and door frames, curtain wall sections, handrails, display frames, solar panel frames and general extrusions, because its moderate strength is paired with excellent extrusion speed, smooth surface and uniform anodizing response.
Q: Can 6063-T5 be machined for fittings?
Yes, 6063-T5 machines easily with standard carbide tooling and produces fine chips and good surface finish; for high-volume turned parts the alloy can be supplied as drawn or extruded bar, and the softness of the alloy keeps tool wear low.
Q: How does 6063-T5 behave outdoors?
The alloy's natural oxide film gives good atmospheric corrosion resistance, and the T5 temper is stable over decades in exterior service; for coastal or industrial environments, anodizing or powder coating adds a further protective layer and improves colour stability.
Q: Can 6063-T5 be re-heat-treated to T6 later?
Technically the section can be re-solution-treated and aged to reach T6 strength, but distortion and surface blistering usually make this impractical on finished profiles; it is better to order the T6 temper directly from the extruder if higher strength is needed.