6061 vs 7075 is the most common aluminum alloy decision on machined parts. 6061-T6 is the general-purpose workhorse: good strength, good corrosion resistance, weldable and economical. 7075-T6 is a high-strength zinc alloy with roughly 70 to 80 percent more tensile strength, but it costs more, resists corrosion less, and is not practical to weld. The right choice depends on load, environment, whether the part will be welded, and budget.
6061 vs 7075: Comparison Table
Property values are typical published minimums or averages for T6 and T651 bar and plate. Cost is a relative per-part index including material, where one 6061 part at quantity 1 equals 100.
| Factor | 6061-T6 / T651 | 7075-T6 / T651 |
|---|---|---|
| Relative cost, qty 1 | 100 | 115 to 135 |
| Relative cost, qty 10 | 40 | 48 to 58 |
| Relative cost, qty 100 | 18 | 23 to 30 |
| Relative cost, qty 1,000 | 10 | 14 to 20 |
| Tensile strength | About 45 ksi | About 83 ksi |
| Yield strength | About 40 ksi | About 73 ksi |
| Hardness | About 95 Brinell | About 150 Brinell |
| Typical machined tolerance | ±0.001 to ±0.005 in | ±0.001 to ±0.005 in; holds thin features well |
| Surface finish | Ra 32 to 63 µin readily | Ra 32 to 63 µin readily, often slightly better |
| Corrosion resistance | Good | Fair; susceptible to stress corrosion in some tempers |
| Weldability | Good | Poor; not recommended for fusion welding |
| Anodizing | Excellent, clear and colors | Good; clear coat can look slightly darker |
| Lead time for stock | Widely stocked | Widely stocked, fewer sizes in some forms |
| Typical use case | Fixtures, housings, brackets, general parts | Aerospace fittings, high-stress parts, tooling, sporting goods |
When 6061 Wins
- General-purpose parts. Housings, plates, fixtures and brackets with moderate loads.
- Welded assemblies. 6061 welds well, though strength drops in the heat affected zone.
- Outdoor and wet environments. Better general corrosion resistance than 7075.
- Cost-sensitive production. Lower material cost and wide availability.
When 7075 Wins
- High strength-to-weight. When a part must carry high loads at low weight, 7075 approaches the strength of many mild steels at about one third the density.
- Thin walls and fine features. The harder alloy resists deflection and burrs, and holds sharp detail.
- Fatigue-loaded fittings. Common in aerospace brackets and structural fittings.
Common Mistakes
- Specifying 7075 by default when 6061 carries the load. It adds material cost with no functional gain.
- Designing a 7075 part that will be welded. Fusion welding 7075 is prone to cracking.
- Using 7075-T6 in corrosive or sustained-stress service without considering T73 or T7351, which improve stress corrosion resistance at some loss of strength.
- Forgetting that anodizing adds thickness. Type III hard coat builds about half its thickness on each surface, which affects tight bores.
- Leaving the temper off the drawing. "6061" alone is not a complete callout; specify T6 or T651 and the material specification.
Machining Notes
Both alloys machine well. 7075 tends to produce smaller chips and a slightly better finish, while 6061 can be gummier in some operations. Plate in the T651 condition is stress relieved by stretching, which reduces distortion on parts with heavy material removal. For thin or long parts, roughing, then releasing and finishing, helps control movement.
How This Applies at Wexmar
Wexmar machines both alloys routinely on our lathes, horizontal machining centers and Swiss-type machines, with material certs and heat-lot traceability available. Anodizing is handled through qualified outside processors that we manage, so plan any finish allowances on the drawing. See materials, CNC milling, and the guide on anodize vs powder coat.
Getting a Quote
If you are unsure which alloy fits, note the load and environment on the RFQ and our estimator will flag it. You can upload a drawing for an instant estimate or call (315) 400-2654.