BS ISO 9618:2016

1   Scope This International Standard specifies the dimensions of hexagon slotted (castellated) nuts, reduced height, normal across flats, with MJ threads, of classifications: 450 MPa/120 °C, 450 MPa/235 °C, 600 MPa/425 °C, 900 MPa/235 °C, 900 MPa/315 °C, 900 MPa/650 °C, 1 100 MPa/235 °C, 1 100 MPa/730 °C, and 1 250 MPa/600 °C.

    NOTE 1  450 MPa, 600 MPa, 900 MPa, 1 100 MPa and 1 250 MPa corresponds to the minimum tensile
     stress which the nut is able to withstand at ambient temperature without breaking
     or cracking when tested with a bolt of a higher strength class. 


    NOTE 2  120 °C, 235 °C, 425 °C, 315 °C, 650 °C, 730 °C and 600 °C corresponds to the maximum
     temperature that the nut is able to withstand without permanent alteration to its
     original characteristics, after ambient temperature has been restored. The maximum
     temperature is conditioned by the surface treatment. 

These nuts are intended to be used with split pins in conformity with [ISO 1234](/search?q=ISO%C2%A01234). 
This International Standard is applicable for the compilation of aerospace product
  standards.