ISO 8279:1997
Aerospace - Nuts, hexagonal, plain, normal height, normal across flats, with MJ threads, classifications: 600 MPa (at ambient temperature)/120 degrees C, 600 MPa (at ambient temperature)/235 degrees C, 900 MPa (at ambient temperature)/425 degrees C, 1 100 MPa (at ambient temperature)/235 degrees C,
standard by International Organization for Standardization, 09/01/1997