This International Standard specifies the mechanical and performance properties for prevailing torque type steel hexagon nuts (including those with flange) when tested over an ambient temperature range of 10 °C to 35 °C. Properties will vary at higher and lower temperature.

It applies to prevailing torque type nuts

• with nominal thread diameters up to and including 39 mm;
• of triangular ISO thread according to ISO 68;
• with diameter/pitch combinations according to ISO 261;
• with thread tolerances 6H according to ISO 965-2;
• with specific mechanical requirements;
• with dimensions as specified in product standards provided they make reference to this International Standard;
• within the temperature range −50 °C to +300 °C for all metal type nuts;
• within the temperature range −50 °C to +I20 °C for non-metallic insert type 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.

Prevailing torque performance decreases with increasing re-use. The nut user should consider the implications of decreased performance prior to re-use.