This standard specifies the characteristics of flat temperature 235 0C, for aerospace applications.steel washers, cadmium plated, for maximum operatin.
EN 2138:1999 history
1999EN 2138:1999 Aerospace series - Washers, flat, in steel, cadmium plated
1998EN 2138:1993/AC:1998 Aerospace Series - Washers, Flat, in Steel, Cadmium Plated Ratified European Text
1993EN 2138:1993 Aerospace series; washers, flat, in steel, cadmium plated