Where do the aluminum alloy numbers like 2024 and A356.0 come from?
These combinations of numbers and, in some cases, letters are defined in ANSI 35.1 covering the designation of aluminum alloys. The four digit designations are for wrought alloys while the designations with three digits followed by a fourth after the decimal point are for cast alloys. The first digit in both designation systems indicates the alloy group with others digits and in some cases letters defining specific alloy compositions or variations of a base alloy composition. A detailed listing of aluminum alloys that have been registered internationally can be obtained from the Aluminum Association.
