This standard specifies the characteristics of prevailing torque type all-metal hexagon nuts with flange and threads from M5 to M20 inclusive, in product Grade A and Grade B, and with property classes 8, 9, 10 and 12. Grade A and Grade B products are respectively used for the nuts with D≤16 mm and D>16 mm.
See Appendix A (Normative) for the gauging of hexagon nuts with flange.
Note: The dimensions of such kind of nuts correspond to those given in GB/T 6177.1 plus prevailing torque feature.
If other technical specifications are required, they should be selected from current standards, for example GB/T 196, GB/T 3098.9 and GB/T 3103.1.
2 Reference Standards
The following documents contain provisions which, through reference into this standard, constitute provisions of this standard. At time of publication, the editions indicated are valid. All the standards will be revised, all parties coming to an agreement according to this standard are encouraged to study whether the latest editions of the following standards are applicable.
GB/T 90-1985 "Acceptance Inspection, Marking and Packaging of Fasteners" (eqv ISO 3269: 1984)
GB/T 196-1981 "General purpose metric screw threads - Basic dimensions" (diameter 1 ~ 600 mm)
GB/T 197-1981 "General purpose screw threads - Tolerances and Fits" (diameter: 1 ~ 355 mm)
GB/T 1237-2000 "Designation System for Fasteners" (eqv ISO 8991: 1986)
GB/T 3098.9-1993 "Mechanical Properties of Fasteners Prevailing Torque Type Steel Hexagon Nuts" (eqv ISO 2320: 1983)
GB/T 6187.1-2000 The following standards are cited：
