Which statement about 2000-8000 series aluminum designations is correct?

Which statement about 2000-8000 series aluminum designations is correct?

• A. The last two digits represent various alloy additions
• B. The last two digits represent density
• C. The last two digits represent color code
• D. The last two digits represent hardness

Answer: (A)

The number system for wrought aluminum alloys uses four digits to identify a specific alloy within a series. The last two digits serve to pick out the exact alloy within that 2xxx–8xxx family, meaning they point to the particular set of alloying additions used to create that variant. In other words, those digits encode the specific composition that defines that alloy variant. Density, hardness, or color aren’t encoded in these last two digits. Those properties depend on the overall composition and processing, not on a digit in the designation. So stating that the last two digits identify the exact alloy additions within the series is the correct way to understand what those digits represent.

The number system for wrought aluminum alloys uses four digits to identify a specific alloy within a series. The last two digits serve to pick out the exact alloy within that 2xxx–8xxx family, meaning they point to the particular set of alloying additions used to create that variant. In other words, those digits encode the specific composition that defines that alloy variant.

Density, hardness, or color aren’t encoded in these last two digits. Those properties depend on the overall composition and processing, not on a digit in the designation. So stating that the last two digits identify the exact alloy additions within the series is the correct way to understand what those digits represent.