6061 and 7075 are the two aluminum alloys we machine most often. Both cut beautifully on a CNC mill or lathe, but they’re built for different jobs. Picking the right one can save money, or save a part from failing in the field.
The short version
- Choose 6061-T6 for most general-purpose parts: brackets, plates, enclosures, fixtures. It’s affordable, corrosion resistant, weldable and anodizes well.
- Choose 7075-T6 / T651 when strength or stiffness-to-weight really matters: highly stressed components, aerospace and performance parts.
Side-by-side comparison
| Property (typical) | 6061-T6 vs. 7075-T6 |
|---|---|
| Ultimate tensile strength | ~45 ksi vs. ~83 ksi |
| Yield strength | ~40 ksi vs. ~73 ksi |
| Density | ~0.098 lb/in³ vs. ~0.101 lb/in³ |
| Corrosion resistance | Very good vs. Fair (often anodized or coated) |
| Weldability | Good vs. Generally not recommended |
| Anodizing | Excellent, consistent color vs. Good, can be less uniform |
| Machinability | Very good vs. Very good, excellent finish |
| Relative material cost | Lower vs. Higher |
Values are typical published figures for reference. Always design to the specification for your application.
When 6061 is the right call
6061 is the workhorse. It’s widely available in plate, bar and tube, costs less, resists corrosion well on its own, and can be welded. For fixtures, enclosures, mounting plates and most industrial components, its strength is more than enough. If a part will be welded into an assembly, 6061 is usually the choice.
When 7075 earns its price
7075 is roughly 75–85% stronger than 6061 in the T6 condition, close to some steels, at about a third of the weight. That makes it the go-to for highly loaded parts where weight matters: aerospace brackets, firearm components, performance automotive and robotics parts, and tooling that sees repeated impact.
The trade-offs: higher cost, lower corrosion resistance (plan on anodizing or another finish in harsh environments), and poor weldability.
Machining notes
Both alloys machine quickly and hold tight tolerances well. 7075 tends to produce a slightly better surface finish and crisper features. Very thin walls and large plates in either alloy can move as internal stress is released; stress-relieved plate (T651) helps keep large parts flat.
Still deciding?
Tell us what the part does, what it’s attached to and what environment it lives in. We’ll recommend the alloy that meets the requirement at the lowest cost. Send us your drawing or read how to prepare it for a faster quote.