This standard stipulates that the thread specifications are M1.6~M64, the performance grades are 6, 8, 10, A2-50, A2-70, A4-50, A4-70, CU2, CU3 and AL4 grades, and the product grades are A and Type B hex nuts, type 1. Grade A is used for D<=16 mm; Grade B is used for nuts with D>16 mm. If other technical requirements are required, they should be selected from current standards (such as GB/T 196, GB/T 3098.2 and GB/T 3103.1).