This standard specifies the characteristics of hexagonal slotted / castellated nuts, reduced height, normal across flats, in heat resisting steel, passivated.
Classification: 900 MPa *) / 650 °C **)
*) 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.
**) 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 dimensions.