When it comes to selecting the right aluminum alloy for structural or architectural applications, 6061 and 6063 are two of the most popular choices. Both belong to the 6xxx series of aluminum alloys, which are known for their strength, corrosion resistance, and excellent workability. However, 6061 and 6063 offer different advantages depending on the project’s specific requirements.
Whether you’re building structural frames, extrusion profiles, automotive parts, or architectural trim, making the right choice between 6061 vs 6063 can impact the performance, cost, and finish of your product.
In this guide, we’ll break down the differences, similarities, and best-use cases for 6061 and 6063 aluminum to help you choose the perfect material for your next application.
Overview of the 6xxx Series Alloys
Both 6061 and 6063 aluminum alloys are heat-treatable and magnesium-silicon-based. This gives them a great balance of moderate-to-high strength, corrosion resistance, and machinability.
They are widely used in:
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Construction
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Transportation
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Aerospace
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Marine
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Architectural industries
The primary difference lies in their mechanical strength, surface finish, and suitability for extrusion and fabrication.
Chemical Composition
Here’s a quick comparison of the chemical makeup of 6061 and 6063:
| Element | 6061 (%) | 6063 (%) |
|---|---|---|
| Magnesium (Mg) | 0.8–1.2 | 0.45–0.9 |
| Silicon (Si) | 0.4–0.8 | 0.2–0.6 |
| Iron (Fe) | ≤ 0.7 | ≤ 0.35 |
| Copper (Cu) | 0.15–0.4 | ≤ 0.1 |
| Chromium (Cr) | 0.04–0.35 | ≤ 0.1 |
| Zinc (Zn) | ≤ 0.25 | ≤ 0.1 |
| Manganese (Mn) | ≤ 0.15 | ≤ 0.1 |
| Titanium (Ti) | ≤ 0.15 | ≤ 0.1 |
The slightly higher magnesium and silicon levels in 6061 contribute to its greater strength, while 6063’s lower copper content improves its corrosion resistance and surface quality.
Mechanical Properties
| Property | 6061-T6 | 6063-T6 |
|---|---|---|
| Tensile Strength (MPa) | ~290 | ~190 |
| Yield Strength (MPa) | ~240 | ~160 |
| Elongation (%) | ~10 | ~12–15 |
| Brinell Hardness | ~95 | ~73 |
| Modulus of Elasticity (GPa) | 69 | 69 |
| Density (g/cm³) | 2.70 | 2.70 |
From the above, it’s clear that 6061 offers significantly higher strength, making it suitable for load-bearing applications. On the other hand, 6063 is more formable and better for aesthetic-focused projects.
Surface Finish
One of the standout features of 6063 is its superior surface finish.
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6063 produces smoother, shinier surfaces after extrusion
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Often used in anodized or powder-coated applications
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6061 has a rougher finish and is more prone to minor surface imperfections
For visible or architectural uses, 6063 is the preferred option, especially if appearance matters.
Workability and Machinability
Both 6061 and 6063 are easy to work with, but their performance varies depending on the application:
6061:
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Excellent machinability
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Handles welding and heat treatment well
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Can be forged, rolled, and extruded
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Slightly harder, which can lead to tool wear in long machining runs
6063:
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Superior extrudability
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Commonly used for complex hollow profiles
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Less prone to cracking during bending
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Ideal for thin-walled structures or decorative trims
If you’re designing complex extrusions or decorative parts, 6063 is easier to form and finish.
Corrosion Resistance
Both alloys provide good corrosion resistance, but:
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6063 offers slightly better corrosion resistance, especially in marine or humid environments
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6061 may require surface treatments in highly corrosive settings due to its higher copper content
Applications near saltwater or chemicals will benefit more from 6063 unless 6061 is properly coated or anodized.
Weldability
Both 6061 and 6063 can be welded, but:
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6061 is stronger after welding when properly heat-treated
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6063 is easier to weld and less likely to crack during the process
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Post-weld heat treatment may be required to restore strength in 6061
For structural welding applications, 6061 is typically the go-to. For aesthetic or light-load welds, 6063 is more forgiving.
Cost and Availability
In general:
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6063 is less expensive due to easier extrusion and processing
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6061 is more widely available in various tempers, bars, plates, and tubes
If budget is a major constraint and structural strength is not the top priority, 6063 offers a better cost-performance ratio.
Typical Applications
| Application Area | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| Structural Framing | Bridges, trusses, towers | Decorative frames, light structures |
| Transportation | Truck bodies, aerospace fittings | Bus frames, bicycle parts |
| Marine | Boat hulls, gangways | Handrails, dock trim |
| Construction | Walkways, roofing structures | Window frames, curtain walls |
| Electronics | Heat sinks, enclosures | Light-duty housings, trim parts |
| Architectural | None or painted applications | Anodized rails, doors, windows |
sasaaluminum supplies both 6061 and 6063 in custom sizes, finishes, and tempers to meet a broad range of project needs.
Choosing the Right Alloy: 6061 vs 6063
Here’s a quick decision guide:
Choose 6061 if you need:
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High strength and load-bearing capability
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Precision machining
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Heat treatment options for strength enhancement
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Structural components with rigorous performance demands
Choose 6063 if you need:
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Excellent surface finish and appearance
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Ease of extrusion and forming
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Good corrosion resistance for outdoor use
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Lightweight profiles with complex shapes
Summary Table
| Feature | 6061 | 6063 |
|---|---|---|
| Strength | Higher | Moderate |
| Surface Finish | Rougher | Smoother |
| Corrosion Resistance | Good | Very Good |
| Machinability | Excellent | Good |
| Weldability | Strong post-weld (with T6) | Easier to weld |
| Extrusion Complexity | Moderate | Excellent |
| Cost | Higher | Lower |
| Typical Use | Structural applications | Architectural profiles |
Conclusion
Both 6061 and 6063 aluminum alloys are excellent materials, each offering unique advantages for different types of applications. The choice depends on what your project demands—strength, appearance, corrosion resistance, machinability, or cost.
At sasaaluminum, we help customers across construction, industrial, and decorative sectors source the right aluminum grade with full technical support and quality assurance. Whether you’re designing a high-load structure or an architectural masterpiece, we have the aluminum solutions to make your project successful.
Post time: Aug-06-2025