US buyers specify aluminium by alloy and temper, such as 6063-T5 for window profiles or 6061-T6 for structural parts. US Customs classifies it by HTS code. Getting both right on your invoice is the first step to an accurate DDP quote, because the HTS code decides the base duty and whether Section 232 applies.
Wrought alloy series
The four-digit designation system maintained by the Aluminum Association groups wrought alloys by their main alloying element:
| Series | Main element | Typical products |
|---|---|---|
| 1xxx | ≥99% aluminium | Foil, electrical conductors, chemical equipment |
| 2xxx | Copper | Aerospace and high-strength parts |
| 3xxx | Manganese | Cookware, beverage can bodies, roofing |
| 4xxx | Silicon | Welding wire, brazing sheet |
| 5xxx | Magnesium | Marine parts, truck bodies, can ends |
| 6xxx | Magnesium + silicon | Extrusions: windows, doors, solar rails, frames |
| 7xxx | Zinc | High-strength sporting and aerospace parts |
| 8xxx | Other elements | Foil (e.g. 8011, 8079) |
Cast alloys use a different, three-digit format (for example A356.0 or 380.0). Many Asian die-casters quote the Japanese grade ADC12, which is close to the US 383 alloy. State the alloy as your buyer specifies it.
Temper codes in one line
F as fabricated · O annealed · H strain-hardened (sheet, foil) · T heat-treated, e.g. T5 (aged after extrusion) or T6 (solution-treated and aged).
HTS Chapter 76 headings
| Heading | Goods |
|---|---|
| 7601 | Unwrought aluminium (ingot, billet) |
| 7604 | Bars, rods and profiles (extrusions) |
| 7606 / 7607 | Plates and sheets over 0.2 mm / foil up to 0.2 mm |
| 7608 / 7609 | Tubes and pipes / fittings |
| 7610 | Structures: doors, windows, frames, curtain wall |
| 7612 | Casks, drums and cans up to 300 litres |
| 7615 | Table, kitchen and household articles |
| 7616 | Other articles of aluminium |
Many aluminium-containing products are classified outside Chapter 76, for example machine parts (Chapter 84), electrical housings (Chapter 85), vehicle parts (Chapter 87) or furniture (Chapter 94). Whether they carry Section 232 duty depends on the derivative annexes.
Common classification mistakes
- Profiles cut and drilled to length for a specific window system may be classified as parts of structures (7610), not as plain profiles (7604).
- Foil thickness: 0.2 mm is the line between foil and sheet, measured without backing.
- Kits mixing aluminium with glass, hardware or plastic need a decision on the essential character.
Documents that support your classification
- A mill test certificate showing the alloy, temper and chemical composition.
- Drawings or spec sheets with dimensions and the degree of processing.
- Smelt and cast country information for the metal — see aluminium import licences.
Related: customs valuation · DDP landed cost for aluminium.