The tightening torque required for an individual screw connection task can be taken from Table 6 as a reference value depending on nominal diameter and friction coefficient.
|
Friction coefficient µtotal 0.10 |
Pretensioning forces Fvmax. [kN] |
Tightening torque MA [Nm] |
||||
|
50 |
70 |
80 |
50 |
70 |
80 |
|
|
M 3 |
0.9 |
1 |
1.2 |
0.85 |
1 |
1.3 |
|
M 4 |
1.08 |
2.97 |
3.96 |
0.8 |
1.7 |
2.3 |
|
M 5 |
2.26 |
4.85 |
6.47 |
1.6 |
3.4 |
4.6 |
|
M 6 |
3.2 |
6.85 |
9.13 |
2.8 |
5.9 |
8 |
|
M 8 |
5.86 |
12.6 |
16.7 |
6.8 |
14.5 |
19.3 |
|
M 10 |
9.32 |
20 |
26.6 |
13.7 |
30 |
39.4 |
|
M 12 |
13.6 |
29.1 |
38.8 |
23.6 |
50 |
67 |
|
M 14 |
18.7 |
40 |
53.3 |
37.1 |
79 |
106 |
|
M 16 |
25.7 |
55 |
73.3 |
56 |
121 |
161 |
|
M 18 |
32.2 |
69 |
92 |
81 |
174 |
232 |
|
M 20 |
41.3 |
88.6 |
118.1 |
114 |
224 |
325 |
|
M 22 |
50 |
107 |
143 |
148 |
318 |
424 |
|
M 24 |
58 |
142 |
165 |
187 |
400 |
534 |
|
M 27 |
75 |
|
|
275 |
|
|
|
M 30 |
91 |
|
|
374 |
|
|
|
M 33 |
114 |
|
|
506 |
|
|
|
M 36 |
135 |
|
|
651 |
|
|
|
M 39 |
162 |
|
|
842 |
|
|
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|
Friction coefficient µtotal 0.40 |
Pretensioning forces Fvmax. [kN] |
Tightening torque MA [Nm] |
||||
|
50 |
70 |
80 |
50 |
70 |
80 |
|
|
M 4 |
0.74 |
1.60 |
2.13 |
1.6 |
3.3 |
4.4 |
|
M 5 |
1.22 |
2.62 |
3.5 |
3.2 |
6.6 |
8.8 |
|
M 6 |
1.73 |
3.7 |
4.93 |
5.3 |
11.3 |
15.0 |
|
M 8 |
3.17 |
6.80 |
9.10 |
12.9 |
27.6 |
36.8 |
|
M 10 |
5.05 |
10.80 |
14.40 |
26.2 |
56.0 |
75.0 |
|
M 12 |
7.38 |
15.8 |
21.10 |
44.6 |
96.0 |
128.0 |
|
M 14 |
10.1 |
21.70 |
26.0 |
71.0 |
152.0 |
204.0 |
|
M 16 |
20.9 |
44.90 |
59.80 |
110 |
237 |
316 |
|
M 18 |
17.5 |
37.50 |
50.10 |
156 |
334 |
447 |
|
M 20 |
22.6 |
48.4 |
64.6 |
223 |
479 |
639 |
|
M 22 |
28.3 |
|
|
303 |
|
|
|
M 24 |
32.6 |
|
|
385 |
|
|
|
M 27 |
41.5 |
|
|
548 |
|
|
|
M 30 |
50.3 |
|
|
740 |
|
|
|
M 33 |
63.0 |
|
|
1013 |
|
|
|
M 36 |
74.0 |
|
|
1296 |
|
|
|
M 39 |
89.0 |
|
|
1694 |
|
|
Friction coefficients µG and µK according to DIN 267 Part 11
Tab. 15: Friction coefficients µG and µK for screws made from stainless steel and anti-corrosion steel
|
Screw made from |
Nut made from |
µtotal When lubricated |
|
|
No lubrication |
MoS2 paste |
||
|
A 2 or A 4 |
A 2 or A 4 |
0.23 - 0.5 |
0.10 - 0.20 |
|
A 2 or A 4 |
AIMgSi |
0.28 - 0.35 |
0.08 - 0.16 |
Friction coefficients µtotal require the same friction value in the thread and under the head / nut support.
Tab. 16: Friction coefficients µG and µK for screws and nuts made from stainless steel and anti-corrosion steel
|
Screw made from |
Nut made from |
Lubricant |
Resilience of connection |
Friction coefficient |
||
|
in thread |
under head |
in thread µG |
under head µK |
|||
|
A 2 |
A 2 |
none |
none |
very high |
0.26 to 0.50 |
0.35 to 0.50 |
|
Special lubricant (chloroparaffin base) |
0.12 to 0.23 |
0.08 to 0.12 |
||||
|
Anticorrosive grease |
0.26 to 0.45 |
0.25 to 0.35 |
||||
|
none |
none |
low |
0.23 to 0.35 |
0.12 to 0.16 |
||
|
Special lubricant (chloroparaffin base) |
0.10 to 0.16 |
0.08 to 0.12 |
||||
|
AIMgSi |
none |
|
very high |
0.32 to 0.43 |
0.08 to 0.11 |
|
|
Special lubricant (chloroparaffin base) |
0.28 to 0.35 |
0.08 to 0.11 |
||||
Hex nuts with a clamping part made from stainless steels tend to seize because of the high thread flank pressure as the thread moulds into the clamping part. Using a friction-reducing agent can remedy the situation. But this should be taken into account accordingly for friction values.