Prevailing torque type all-metal Hex flange nuts
This International Standard specifies the characteristics of prevailing torque type all-metal hexagon flange nuts and threads from M5 to M20 inclusive, in product grade A for threads up to and including M16 and product grade B for threads above M16, and with property classes 8, 9, 10 and 12.
Hex flange nuts hardness test
For routine inspection, hardness tests may be carried out on the bearing surface of the nut and the hardness shall be taken as the mean of three values spaced 120" apart. In case of dispute, the hardness tests shall be carried out on a longitudinal section through the nut axis and with impressions placed as close as possible to the nominal major diameter of the nut thread.
The Vickers hardness test is the reference test and where practicable a load of HV30 shall be applied.
Hex flange nuts figure