1.1 This International Standard specifies the mechanical and performance requirements for prevailing torque type steel hexa-gon nuts
a) with thread sizes M3 to M39 inclusive;
b) with specific strength requirements;
c) with dimensions as specified in product standards;
d) within the following temperature ranges :
1) - 50 to + 300 °C for all-metal non-plated nuts;
2) - 50 to + 230 °C for all-metal plated nuts;
3) - 50 to + 120 °C for non-metallic insert nuts.
It does not apply to nuts requiring special properties which may require special materials or coatings to improve
— weldability;
— corrosion resistance;
— performance outside the above specified temperature ranges.
Unless stated othcrwise, all references to nuts in this International Standard are to both prevailing torque hexagon nuts and prevailing torque hexagon flange nuts.
1.2 Torque tension requirements for nuts of two types, NF (normal friction) and LF (low friction), in sizes M6 to M24 inclusive, and of property classes 8, 9 and 10 will be covered in a future International Standard.
1.3 No recommendations, except those for prevailing torques, are currently available for fine thread nuts.
SIS SS-ISO 2320:1988 history
1988SIS SS-ISO 2320:1988 Prevailing torque type steel hexagon nuts - Mechanicai and performance properties