1 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 lenghts / < 10d (or longer if specified);
— property dass 12.9;
— property classes 8.8, 9.8 and 10.9 when specified in product standards or agreed between supplier and purchaser.
2 Where the permissible limits for surface discontinuities indicated in clause 3 occur, the minimum values for the mechanical and functional proparties specified in ISO 898-1 should still be met.
When fatigue strength requirements are specified, the fatigue strength should not be lower than that obtained on bolts without defects taken from the same lot.
NOTES
3 The figures in clause 3 are examples only. They apply correspond-
ingly also to other types of bolts, screws and studs.
4 The individual figures show the surface discontinuities exaggerated in some cases for clarity.
SIS SS-ISO 6157-3:1992 history
1992SIS SS-ISO 6157-3:1992 Fasteners — Surface discontinuities — Part 3: Bolts, screws and studs for special requirements