Bolting
Bolting Bolting material for cast-iron flanges is listed in ASME B16.1. Generally, ASTM A307, grade B material is suitable. For steel flanges, acceptable bolting material is listed in ASME B16.5. Threading. Bolts and nuts normally are threaded in accordance with ASME B1.1 Standard for Unified Screw Threads. In diameters 1 in and smaller, Class 2A fits on the bolt or stud and Class 2B on the nut applies with the coarse thread series. In diameters 1¹⁄₈ in and larger, the eight-