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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.

You can 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, you can view any of our other information about the material, or contact us to further an enquiry.