0 said that the alloying elements and impurities limit content control : 0represent the original alloy, said its impurities content without special control limit, modified 1-9 alloy, to one or more of the individual impurity elements or alloys limit content with special control.

24different alloys: indicates the minimum aluminum alloy after the decimal point two, such as 1050aluminum content of 99.50%, two digit has no special meaning, is only used to identify the same group in different alloys.

T said heat treatment. T back with one or more numbers, such as T3, said the T3 heat treatment. Different figures represent different heat treatment.