Compare 6061 and 7075 aluminum for structural CNC parts. Learn about strength, machinability, corrosion resistance, cost, and when to use each alloy.
Choosing the right aluminum alloy isn’t just about picking a number from a chart — it’s about understanding how your part behaves under stress, how it's fabricated, and how it’s expected to perform over time. Two of the most common choices for structural components in aerospace, robotics, and industrial systems are 6061 and 7075. But they are not interchangeable.
If you’re asking yourself this question, it means you're already thinking like an engineer. Let’s go deeper.
Both 6061 and 7075 are high-strength aluminum alloys, but their core characteristics differ fundamentally.
6061 Aluminum
A versatile, general-purpose alloy known for good corrosion resistance, excellent weldability, and decent strength. It’s been used in everything from aircraft fittings to bike frames and marine parts.
7075 Aluminum
A high-strength, aerospace-grade alloy famous for its exceptional strength-to-weight ratio, but at the cost of poorer weldability and lower corrosion resistance unless treated.
In plain terms: 7075 is stronger; 6061 is more forgiving.
Structural parts are subject to more than just static loads. They may flex, twist, vibrate, or face environmental challenges like moisture, UV exposure, or chemicals. That’s why strength alone isn’t the only factor.
Using 7075 where 6061 would suffice may unnecessarily increase your material cost and complicate your manufacturing process — especially if welding or forming is required. On the other hand, using 6061 in a high-stress load-bearing part could lead to early fatigue failure.
| Property | 6061-T6 | 7075-T6 |
|----------------------------|------------------------|------------------------|
| Ultimate Tensile Strength (MPa) | ~290 | ~570 |
| Yield Strength (MPa) | ~240 | ~500 |
| Elongation at Break (%) | ~12 | ~10 |
| Hardness (Brinell) | ~95 | ~150 |
| Density (g/cm³) | 2.70 | 2.81 |
| Thermal Conductivity (W/m·K) | 167 | 130 |
| Corrosion Resistance | Excellent | Fair (requires coating)|
| Weldability | Excellent | Poor |
| Cost Index (vs. 6061 = 1.0) | 1.0 | 1.8–2.2 |
> Note: All values represent typical properties and may vary by supplier or heat treatment.
Use 7075 aluminum when your part:
Requires maximum tensile strength
Will undergo cyclic or impact loading
Has tight weight constraints (e.g., aerospace or drones)
Doesn’t require welding or post-forming
Will be anodized or coated to improve corrosion resistance
Use 6061 aluminum when your part:
Requires welding or complex machining
Needs good corrosion resistance without coating
Is part of a marine or outdoor assembly
Doesn’t require extreme strength
Needs to be cost-effective in prototyping or small runs
In short: 7075 is like carbon fiber — powerful but touchy; 6061 is like a dependable steel — not as flashy but gets the job done.
From a machinist’s point of view:
7075 machines beautifully, producing clean chips and fine finishes. But it's more expensive, and any secondary forming (like bending or welding) is more difficult.
6061 is easier to work with in prototyping and mixed processes. It welds cleanly, takes to anodizing well, and costs significantly less.
If you're CNC machining your structural part, both alloys are excellent. But complex shapes, multi-pass toolpaths, or welding will lean the advantage toward 6061.
Also, note: 7075 anodizes darker and unevenly compared to 6061. If aesthetics or branding matter, this is worth considering.
The truth is, neither alloy is objectively better. They're just better for different purposes.
Think of 7075 as a performance athlete — specialized, expensive, and high maintenance.
6061 is the everyday all-rounder — reliable, economical, and easier to train.
If your structural part must bear high loads at minimal weight, choose 7075.
If your part will be exposed to the environment, welded, or iterated often, go with 6061.
Need help choosing between 6061, 7075, and other alloys?
- Use our [Material Selection Tool](https://www.ekinsun.ltd/tools/material-selection-tool) to compare strength, machinability, and cost across dozens of materials.
- Check out our [CNC Materials Comparison Guide](https://www.ekinsun.ltd/engineering-blog/cnc-materials-comparison-guide) for an in-depth breakdown of common alloys used in precision machining.
- Explore our [Aluminum Machining Services](https://www.ekinsun.ltd/cnc-machining/aluminum) to see how 6061 and 7075 are used in real-world applications.
This article is written by the team at EKINSUN Precision Manufacturing, with over 10 years of experience machining both 6061 and 7075 aluminum for applications ranging from robotics and consumer electronics to aerospace brackets and structural jigs.
We’ve seen the results when people choose the wrong alloy — and it’s always more expensive to fix than to ask early.
Still not sure?
If you have a drawing or model in hand, send it to our team — we’ll help you match the right alloy to your budget and performance needs, before the chips start flying.
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