scope:

This part of ISO 6157 establishes limits for various types of surface discontinuities on bolts, screws and studs for special requirements. It applies to bolts, screws and studs with - nominal thread diameters 5 mm and larger; - product grades A and B; - nominal lengths l 10d (or longer specified); - property class 12,9; - property classes 8,8, 9,8 and 10,9 when specified in product standards or agreed between supplier and purchaser. Where the permissible limits for surface discontinuities indicated in clause 3 occur, the minium values for the mechanical and functional properties specified in ISO 898-1 should still be met. When fatique strength requirements are specified, the fatique strength should not be lower than that obtained on bolts without defects taken from the same lot.