1.The international four-digit font can be directly referenced.

2. Deformed aluminum and aluminum alloys that are not named international four-digit system grades shall be named with four-character grades (but experimental aluminum and aluminum alloys shall be named with prefix X plus four-character grades).

3.The first, third, and fourth digits of the four-character system are Arabic numerals, and the second digit is an English uppercase letter (except C, I, L, N, O, P, Q, and Z). The first digit of the grade indicates the aluminium and aluminium alloy groups. In addition to the modified alloy, aluminum alloy groups according to the main alloy elements (6XXX series according to Mg2Si) to determine. Major alloying elements refer to alloying elements whose arithmetic mean limit content is the largest. When the arithmetic mean limit content of more than one alloy element is the maximum, the alloy groups should be determined according to the order of Cu, Mn, Si, Mg2Si, Zn and other elements. The second letter of the grade indicates the modification of the original pure aluminum or aluminum alloy, and the last two digits are used to identify the different aluminum alloys in the same group or to indicate the purity of the aluminum.