Bolt Tightening - Torque versus Tension

[clurt]

Hi guys,

Bringing myself back up to speed with bolt tightening, would really appreciate if anyone has some resources or answers to these questions:

1. The proof load for torque tightening, and proof load for tension tightening
2. Main advantages and disadvantages between the two
3. What is the equivalence between the two. For example... M48 Bolt was tensioned to using 750kN of force, now this is unavailable. What is the torque required to achieve the equivalent tightening, 5000Nm, 6000Nm?
4. Is proof load related to the force that a bolt is tensioned?
5. What are the stresses in bolt tensioning. Is it a percentage of the yield strength?
6. Difference between bolt being stressed and bolt force?
7. Is there an equation that can translate tension and torque tightening, vice versa.

Thanks

 

[jrmichler]

Any undergrad machine design textbook has a chapter on bolted joint design. Here is a good online resource: http://www.hexagon.de/rs/engineering fundamentals.pdf. And another good resource: https://www.machinedesign.com/faste...threaded-fastener-torque-tension-relationship.