Alloy series
7xxx Series — Aluminum–Zinc
The highest-strength commercial series. Requires full traceability.
Properties
7xxx — Traits and Typical Uses
| Common grades | 7005 · 7050 · 7075 · 7A09 |
|---|---|
| Key traits | Highest strength · Heat-treatable · Lower corrosion resistance (stress corrosion risk) · Requires EN 10204 3.1 |
| Typical uses | Aircraft structure · Aerospace tooling · Bicycle frame · High-stress mold |
| Heat treatable | Yes — T4 / T5 / T6 / T651 tempers available |
Every grade
All 4 Grades in the 7xxx Series
The series tells you the alloying element. The grade tells you how much of it, and that is what decides strength, corrosion behaviour and price. Grades with a detail page carry composition limits and temper-by-temper mechanicals.
| Grade | What it is for | Detail |
|---|---|---|
| 7005 | Weldable 7xxx for bicycle frames and structural tube, where 7075 cannot be welded. | On request |
| 7050 | Thick-section aerospace alloy with better toughness and corrosion resistance than 7075. | On request |
| 7075 | Highest strength in normal supply; aerospace fittings and tooling, never welded. | Specs → |
| 7A09 | Chinese-registry high-strength Al-Zn-Mg-Cu grade comparable to 7075. | On request |
A grade without a detail page is still quotable — the range, temper and certificate are confirmed on the offer rather than published as a table.
Specifying
How a 7xxx Order Is Written
Four things decide whether the material that arrives is the material you meant. None of them is the alloy number, which is usually the only thing on the enquiry.
1 — Temper, not just grade
The suffix sets the mechanical condition and changes strength more than the alloy does. This series is heat treatable, so state T4, T5, T6 or T651 explicitly — and specify T651 for thick plate that will be machined, because stress relief happens at that step.
2 — The product standard
ASTM, EN and GB do not have identical tolerance tables. Name the standard on the purchase order — 7xxx material supplied to a different edition can be perfectly good metal and still fail your incoming inspection.
3 — Thickness and its tolerance band
Nominal thickness is not the delivered thickness. State the band you can accept, especially near the sheet-plate boundary at 6.35 mm, where the product changes from cold-rolled sheet to hot-rolled plate.
4 — Certificate type
EN 10204 2.2 is a statement against general production; 3.1 carries the actual test values for your heat and is signed by an inspection representative independent of production. Say which one your file needs before the order is placed.
Choose
How 7xxx Compares
Choose 7xxx when
Aircraft structure · Aerospace tooling · Bicycle frame · High-stress mold
Think again if
The part is welded or sits in a corrosive environment — 7xxx has stress-corrosion risk and needs proper temper selection (T73/T74).
Other series
- 1xxx — Commercial Pure AluminumExcellent formability · Excellent corrosion resistance · High thermal/electrical conductivity · Non-heat-treatable
- 2xxx — Aluminum–CopperHigh strength after heat treatment · Good machinability · Poor corrosion resistance bare · Weldability varies
- 3xxx — Aluminum–ManganeseGood formability & weldability · Better strength than 1xxx · Excellent corrosion resistance · Non-heat-treatable
- 5xxx — Aluminum–MagnesiumExcellent marine corrosion resistance · Good weldability · Work-hardenable · Higher strength than 3xxx
- 6xxx — Aluminum–Magnesium–SiliconHeat-treatable (T5/T6) · Excellent extrudability · Good weldability · Excellent anodizing response
- 8xxx — Aluminum–Other (Foil & Special)High elongation · Low pinhole count · Clean surface · Non-heat-treatable
What goes wrong
Failure Modes That Show Up in 7xxx
These are the defects we get called about on this series, what causes them, and what to put on the order so they do not happen. Each page covers cause, measurement and specification.
- Camber and Wavy Edge in Sheet & CoilWhy aluminum sheet and coil show camber or wavy edge, how it is measured under EN 485 and ASTM B209, and what to specify to keep it off your automatic line.
- Weld Cracking & Sensitization in 5xxx PlateWhy 5083 aluminum plate cracks or corrodes in service: Sensitization above 65°C, H116 vs H32 temper, filler wire choice, and the ASTM G67 test to specify.
- Anodizing Color VariationWhy anodized aluminum varies in color between batches: alloy drift, extrusion parameters and bath control. How film thickness and color are specified.
- All eight failure modes →Symptom, cause, measurement, and the line to add to the order
Not Sure Between Two Grades?
Send the end use and the environment, and we will say which one we would run — including when the answer is "neither".
Ask for a Grade Recommendation