This part of GB/T 6185 specifies the type, size, technical conditions and marks of fine-thread type 2 all-metal hexagonal lock nuts. This part is applicable to Type 2 all-metal hexagonal lock nuts with nominal thread diameters of 8 mm to 36 mm, fine pitch threads, performance classes 8, 10 and 12, and product classes A and B. Grade A is used for D≤16 mm; Grade B is used for nuts with D>16 mm.