Tightening Torques for Stainless Steel Bolts
Minimum breaking torque (M b,min) for austenitic stainless steel bolts and screws between M 1.6 and M 16 (course threads) are shown in table 4 of EN ISO 3506-1:1997. This shows torque values in Nm for properties classes 50, 70 and 80 as shown in the table below. This applies to 'grades' A1, A2, A3, A4 and A5. Tightening torque values are not given in this standard.
Minimum breaking torque values
Torque values are not given for martensitic stainless steel (C1, C3, C4) or ferritic stainless steel (F1) grades. The standard states that these values are to be agreed between manufacturer and user.
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Min breaking torque Nm for properties class |
| |
50 |
70 |
80 |
| M1.6 |
0.15 |
0.2 |
0.24 |
| M2 |
0.3 |
0.4 |
0.48 |
| M2.5 |
0.6 |
0.9 |
0.96 |
| M3 |
1.1 |
1.6 |
1.8 |
| M4 |
2.7 |
3.8 |
4.3 |
| M5 |
5.5 |
7.8 |
8.8 |
| M6 |
9.3 |
13 |
15 |
| M8 |
23 |
32 |
37 |
| M10 |
46 |
65 |
74 |
| M12 |
80 |
110 |
130 |
| M16 |
210 |
290 |
330 |
Maximum tightening torque, yield loads and failure loads for austenitic stainless steel fasteners
Tightening torques, yield loads and failure loads are not given in the EN ISO 3506-1:1997 standard
Related References:
ASTM A453 High-Temperature Bolt with Expansion Coefficient
Shear and Tension Capacity of Stainless Steel Bolts
Tightening Torques for Stainless Steel Bolts
Stainless Steel Tensile and Proof Stress Of Metric Bolts Screws
Steel Bolts Strength Specification
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