N/A

The aluminum industry uses a four-digit index system for the designation of its wrought aluminum alloys.
As outlined below, the first digit indicates the alloy group according to the major alloying elements.

1xxx Series
In this group minimum aluminum content is 99% and there is no major alloying element. The second digit indicates modifications in impurity limits. If the second digit is zero, there is no special control on individual impurities. Digits 1 through 9, which are assigned consecutively as needed, indicate special control of one or more individual impurities. The last two digits indicate specific minimum aluminum content. Although the absolute minimum aluminum content in this group is 99%, the minimum for certain grades is higher than 99%, and the last two digits represent the hundredths of a per cent over 99. Thus, 1030 would indicate 99.30% minimum aluminum. without special control on individual impurities. The designations 1130, 1230, 1330, etc.. indicate the same purity with special control on one or more impurities. Likewise 1100 indicates minimum aluminum content of 99.00% with individual impurity control.

2xxx至9xxx系列
The major alloying elements are indicated by the first digit, as follows:
2xxx Copper
3xxx Manganese
4xxx Silicon
5xxx Magnesium
6xxx Magnesium and silicon
7xxx Zinc
8xxx Other element
9xxx Unused series

第二个数字表示合金修饰。如果第二位数为零。它指示原始合金：数字1至9，连续分配，指示合金修饰。最后两个数字没有特殊的意义，仅用于识别该组中的不同合金。

实验合金
实验合金是根据四位数系统指定的，但是它们的前缀为字母X。当合金成为标准配合时，前缀被删除。在开发过程中，在将它们指定为实验之前，新合金由其发起人分配的序列号确定。分配X号时停用序列号的使用。