BS EN ISO 2320-2015 pdf download.Fasteners一Prevailing torque steel nuts – Functional properties.
5 Thread
Threads for prevailing torque nuts shall be in accordance with ISO 965-2 except for the prevailing torque feature:
a) for prevailing torque non-metallic insert type nuts, the GO gauge shall be suitable for free installation (by hand) until it Is seated against the prevailing torque feature;
b) for prevailing torque all metal type nuts, the GO gauge shall be suitable for free installation (by hand) to one pitch at least.
6 Lubrication
At the option of the manufacturer, a lubricant may be applied to the manufacturing lot to fulfil the functional requirements.
7 Mechanical properties of prevailing torque nuts
The mechanical properties of prevailing torque nuts shall conform to ISO 898-2.
With regard to proof load, the test method specified in 92 shall apply.
8 Functional requirements for prevailing torque properties
The prevailing-on torque shall not exceed the value specified br the applicable nut in Tables ito 7.
The prevailing-off torque shall exceed the value specified for the applicable nut in Tables ito 7.
For delivery inspection, the first installation/removal test applies, unless otherwise agreed.
For initial type testing and in case of dispute, a 5th removal test shall also be applied unless otherwise agreed.
Prevailing torque performance decreases as a function of the number of reuses; the consumer shall take into consideration the consequences of the decreased performance before any reuse of the nut.
By request of the customer, a temperature influence test for prevailing torque non-metallic insert type nuts as specified in Annex A may be carried out.BS EN ISO 2320 pdf download.