Nuts: a) Material: ASTM A194 2H, ASTM A563, ASTM B150 C63000, Duplex SS31803 b) Specification: ANSI B 18.2.2, DIN 934,DIN985 3) Flat and spring washers: a) Material: carbon steel and stainless steel, ASTM B150 C63000, Duplex SS31803 b) Specification: ANSI B 18.22.1, ANSI B18.21.1 DIN125, DIN127