The chemical composition of an aluminum alloy is the first thing a mill certificate states, and the one place a buyer can check a claim against a public number. This page is the chemical composition limits for the common aluminum grades, in the form the three main standards — ASTM (North America), EN (Europe) and GB (China) — all refer back to.
The key point: the Aluminum Association registered limits are the common source. ASTM B209, EN 573-3 and GB/T 3190 all define the same alloys with the same ranges, because they all trace back to the AA Teal Sheets. There are small notation differences, but the numbers are the same metal.
Composition limits, common grades
Values are weight percent. "Remainder" means aluminum is the balance.
| Grade | Si | Fe | Cu | Mn | Mg | Zn | Al |
|---|---|---|---|---|---|---|---|
| 1050 | 0.25 max | 0.40 max | 0.05 max | 0.05 max | 0.05 max | 0.05 max | 99.50 min |
| 1100 | 0.95 max (Si+Fe) | — | 0.05–0.20 | 0.05 max | — | 0.10 max | 99.00 min |
| 3003 | 0.60 max | 0.70 max | 0.05–0.20 | 1.0–1.5 | — | 0.10 max | Remainder |
| 5052 | 0.25 max | 0.40 max | 0.10 max | 0.10 max | 2.2–2.8 | 0.10 max | Remainder |
| 5083 | 0.40 max | 0.40 max | 0.10 max | 0.40–1.0 | 4.0–4.9 | 0.25 max | Remainder |
| 6061 | 0.40–0.80 | 0.70 max | 0.15–0.40 | 0.15 max | 0.80–1.20 | 0.25 max | Remainder |
| 6082 | 0.70–1.30 | 0.50 max | 0.10 max | 0.40–1.0 | 0.60–1.20 | 0.20 max | Remainder |
| 6063 | 0.20–0.60 | 0.35 max | 0.10 max | 0.10 max | 0.45–0.90 | 0.10 max | Remainder |
| 7075 | 0.40 max | 0.50 max | 1.2–2.0 | 0.30 max | 2.1–2.9 | 5.1–6.1 | Remainder |
For the foil grades, the limits are the tight ones that matter at thin gauge: 8011 is 0.50–0.90% Si and 0.60–1.00% Fe (the iron and silicon that resist pinholes), and 1235 is 99.35% Al minimum with Si+Fe capped at 0.65%.
The full element-by-element table — including chromium, titanium and the "others, each / others, total" rows — is on each grade reference page.
Where the three standards differ
The alloys are the same, but the way the standards express them is not identical, and the differences cause real disputes:
- Notation. EN writes EN AW-5052 (and adds the ISO designation AlMg2.5); GB writes 5052 with Chinese registration; ASTM writes 5052 with a UNS number (A95052). Same metal, three names.
- Scope and exclusions. Not every standard covers every alloy or temper. A grade listed in GB/T 3190 may have no ASTM equivalent for a specific temper, and assuming coverage before checking is a mistake.
- "Others" rounding. The each/total impurity limits are expressed slightly differently, and the rounding conventions differ — small, but they matter when a certificate is being checked to two decimal places.
The practical rule is the same as for dimensions: name one standard on the order. If the drawing cites ASTM and the material is made to GB, the composition almost always matches, but the certificate has to be written against the right designation.
How to read a composition limit
The notation does the heavy lifting, and it is worth reading precisely:
- "0.40 max" means the element may not exceed 0.40%, and any value at or below is conforming.
- "0.05 – 0.20" means the element must fall within the range — not just below a cap. A copper content of 0.02% in 1100 is out of range, not just unusual, and it fails.
- "Remainder" means aluminum is whatever is left after the other elements, and there is no minimum to state.
- "99.50 min" means a minimum aluminum content, used for the pure grades where purity is the definition of the alloy.
The range entries are where certificates get rejected. A buyer who only checks the caps can miss an element that fell below its required range, and that is a non-conforming heat just as surely as one that exceeded a cap.
The checksum on any certificate
When a mill certificate lands, the fastest check is: do the reported figures sit inside the registered limits for that grade? Pull the grade's limits from the table above (or the grade page), and check every reported element against its cap or range. It takes a minute and catches the two classic problems — a wrong grade recorded, or a heat that is out of range on an element the buyer never looked at.
The limits in this table are the Aluminum Association registered ranges, which ASTM B209 and EN 573-3 both refer back to. For the grade-by-grade tables with every element and the temper-specific mechanical values, see the alloy reference pages. If you are checking a certificate and a figure does not square, send it over — the answer is almost always in the ranges.