Torque is a measure of the application of force and is used to create tension in threaded fasteners. For example, when fasteners are tightened, the thread converts the applied torque into tension into the shank of the bolt which in turn creates the clamping force so often desired.
There are a number of other factors that can have an effect on the torque of a fastener too, such as the material, the condition that the fasteners are in, and finishes that the fastener might have and whether the fastener is lubricated or not.
It is only an indirect indication of tension and care should be taken when under or over-tightening the fastener as this can result in equipment failure.
The below information is by no means a recommendation, but can be used as a guide – actual strengths and conditions may vary.
Duplex and Torque
We’ll be covering the torque specifications for some of the exotic materials that we can provide for fasteners, including Duplex and Super Duplex, Hastelloy, Incoloy, Inconel, Molybdenum, Monel and many others such as Tantalum, Titanium, Waspaloy and Zirconium.
Duplex and Super Duplex
Duplex and Super Duplex Stainless Steel provide a number of advantages in fasteners and are popular due to their impressive attributes including high strength and corrosion resistance.
Duplex 2205 Bolt/Screw
The below is calculated from a yield strength of 70ksi
| Nominal Diameter (in) | Threads (in) | Torque ft-lb (Dry) | Torque ft-lb (Lubricated) |
|---|---|---|---|
| 1/4″ | 20 | 6.5 | 4.8 |
| 28 | 7.4 | 5.5 | |
| 5/16″ | 18 | 13.2 | 10.0 |
| 24 | 14.7 | 11.0 | |
| 3/8″ | 16 | 23.5 | 17.7 |
| 24 | 26.6 | 19.9 | |
| 7/16″ | 16 | 37.6 | 28.2 |
| 24 | 42.0 | 31.5 | |
| 1/2″ | 13 | 57.4 | 43.0 |
| 20 | 64.7 | 48.5 | |
| 9/16″ | 12 | 82.7 | 62.1 |
| 18 | 92.3 | 69.2 | |
| 5/8″ | 11 | 114.2 | 85.7 |
| 18 | 129.3 | 97.0 | |
| 3/4″ | 10 | 203 | 152 |
| 16 | 226 | 170 | |
| 7/8″ | 9 | 326 | 245 |
| 14 | 361 | 270 | |
| 1″ | 8 | 490 | 368 |
| 14 | 549 | 412 | |
| 1-1/4″ | 7 | 853 | 639 |
| 12 | 944 | 708 | |
| 1-1/2″ | 6 | 1484 | 639 |
| 12 | 1669 | 1252 |
Super Duplex 2507 Bolt/Screw
The below is calculated from a yield strength of 80ksi
| Nominal Diameter (in) | Threads (in) | Torque ft-lb (Dry) | Torque ft-lb (Lubricated) |
|---|---|---|---|
| 1/4″ | 20 | 7.4 | 5.5 |
| 28 | 8.4 | 6.3 | |
| 5/16″ | 18 | 15.1 | 11.4 |
| 24 | 16.8 | 12.6 | |
| 3/8″ | 16 | 26.9 | 20.2 |
| 24 | 30.4 | 22.8 | |
| 7/16″ | 14 | 43.0 | 32.3 |
| 20 | 48.0 | 36.0 | |
| 1/2″ | 13 | 65.6 | 49.1 |
| 20 | 73.9 | 55.4 | |
| 9/16″ | 12 | 94.5 | 71.0 |
| 18 | 105.5 | 79.1 | |
| 5/8″ | 11 | 130.5 | 97.9 |
| 18 | 147.8 | 110.9 | |
| 3/4″ | 10 | 232 | 174 |
| 16 | 258 | 194 | |
| 7/8″ | 9 | 373 | 280 |
| 14 | 412 | 309 | |
| 1″ | 8 | 560 | 420 |
| 14 | 628 | 471 | |
| 1-1/4″ | 7 | 975 | 730 |
| 12 | 1079 | 809 | |
| 1-1/2″ | 6 | 1696 | 1271 |
| 12 | 1908 | 1430 |
Contact Us For More Information on Duplex and Super Duplex
There’s a reason that Duplex Stainless Steels are being used more and more commonly within the fastener industry.
View our range of High Corrosion Resistant Fasteners, including Duplex, here.
If you require more information about how these fasteners and fixings can work in your application, please get in touch.
