Axial force on a torqued bolt

[KevinH673]

Say I am tightening a bolt at a specified torque, what is a calculation to find the axial force that bolt is pulling the material?

I've found T=0.2*D*F

where T=torque and D=diameter of bolt.

Is this correct?

 

[desertfox]

The short answer is yes, but how accurate do you want to be as that is only an estimate.
Have a look on this site for some good information:-

http://www.roymech.co.uk/Useful_Tables/Screws/index_screws.htm

 

[Dinosaur]

The problem with using torque to establish the tension in a bolt is that the friction in the torque value is unknown. I think it is better to measure the rotation of the nut to compute the strain in the bolt. There is a spec on high strength bolting using ASTM A325 and ASTM A490 bolts that could give you some more discussion. We use the turn-of-the-nut method in my industry.

 

[MintJulep]

We have discussed torque-tension here many times. Take some time to search the archives.

Take some time to look at the FAQs

faq725-536