ISO 10684 Specification

Special requirements for bolts, screws and nuts with thread sizes M8 and M10

General

For M8 and M10 ultimate tensile loads and proof loads lower than those specified in ISO 898-1 and ISO 898-2 are specified in this annex taking into account the relatively large fundamental deviations according to 6.2.2 and 6.2.3.

For nuts tapped oversize, the reduced overlap of thread M8 and M10 significantly reduces the proof load values as compared with those given in ISO 898-2.

For bolts and screws with undersized threads, the stress areas for M8 and M10 are significantly smaller than fgthe stress areas given in ISO 898-1.

Minimum proof loads for hexagon nuts tapped oversize to tolerance class 6AZ or 6AX after coating

According to 6.2.2 nuts may be tapped oversize to tolerance class 6AZ or 6AX in accordance with ISO 965-5 and Annex B. For thread sizes M8 and M10 tolerance class 6AZ gives the largest fundamental deviation. Consequently, for thread sizes M8 and M10 the fundamental deviations for tolerance class 6AZ are used to establish the proof loads as given in below Table. Stresses under proof load are given in below Table.
All other mechanical property requirements as given in ISO 898-2 are valid.
For test methods, see ISO 898-2.

Proof loads for nuts with threads of tolerance classes 6AZ and 6AX
Thread Pitch of thread Nominal Property Class
5 6 8 9 10
Marking
(d) p As 5Z/5X 6Z/6X 8Z/8X 9Z/9X 10Z/10X
mm mm2 Proof load
N
M8 1.25 36.6 17 300 20 000 25 500 27 600 30 600
M10 1.5 58.0 28 000 33 000 42 200 45 600 50 400
Stresses under proof load for nuts with threads of tolerance classes 6AZ and 6AX
Thread
(d)		 Property Class
5 6 8 9 10
Marking
5Z/5X 6Z/6X 8Z/8X 9Z/9X 10Z/10X
Stress under Proof load
N/mm2
M8 473 546 698 754 835
M10 493 569 728 786 870
Minimum ultimate tensile loads and proof loads for bolts and screws with threads undersized to tolerance class 6az before coating

According to 6.2.3 bolts, screws and external threads have to be threaded undersize to tolerance class 6az in accordance with ISO 965-4 and Annex B. For thread sizes M8 and M10 tolerance class 6az gives large fundamental deviations and this reduces the stress area. Consequently, for thread sizes M8 and M10, the ultimate tensile loads and proof loads are reduced. For principles of calculation, see Annex C. The reduced values are given in Tables A.3 and A.4.
All other mechanical property requirements as given in ISO 898-1 are valid.
For test methods, see ISO 898-1.

Minimum ultimate tensile loads for bolts and screws with threads of tolerance class 6az
Thread
(d)		 Stress area A saz Property Class
4.6 5.6 8.8 10.9
mm 2 4.6U 5.6U 8.8U 10.9U
Minimum ultimate tensile load(A saz X R m.min)
N
M8 33.2 13 300 16 600 26 600 34 500
M10 53.6 21 400 26 800 42 900 55 700
Proof loads for bolts and screws with threads of tolerance class 6az
Thread
(d)		 Stress area A saz Property Class
4.6 5.6 8.8 10.9
mm 2 4.6U 5.6U 8.8U 10.9U
Minimum ultimate tensile load(A saz X S p)
N
M8 33.2 7 470 9 300 19 300 27 600
M10 53.6 12 100 15 000 31 100 44 500