This part of GB/T 6185 specifies the type dimensions, technical conditions and marks of type 2 all-metal hexagonal lock nuts. This part applies to type 2 all-metal hexagonal lock nuts with thread specifications M5~M36, performance grades 5, 8, 10 and 12, and product grades A and B. Grade A is used for D≤16 mm; Grade B is used for nuts with D>16 mm.