The amount of Force due to 120 kNM Torque on a Nut of a Stud Bolt 1

[SIAVASH54]

Dear Sirs

We are working on an offshore sub sea pipe spool piece installation project.
I would like to know the amount of force ( or pressure ) due to 120 KNM torque on 2 3/8" Dia nut of 1 1/2" stud bolt .
This is bolt of a 600# 16" flange.

Please guide me regarding this matter.

Regards
Siavash

 

[ColonelSanders83]

Get a copy of Mark's or Machinerys handbook and go through the torque calculation section. You have not provided enough information to give you an answer showing that little more research on your part is nessacery. One you have read and understood the information in these tomes, you will probably be able to answer your own question.

Additionaly I would find out if there is a governing specification or standard for this calculation as this is for a subsea application.

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[Gorpomon]

Siavash,

If I understand your question correctly, you want to know the force or pressure that the torque is sealing?

There is no one torque for a force. The method you use to calculate torque from required bolt load, the installation tools and method, the bolt, gasket and flange material ALL affect what torque you use. Furthermore at some point torque is a decision, how much variation you will allow in it, and perhaps if it will be to some percentage of your other materials yield or tensile strengths. Perhaps the original engineer wanted to meet a certain tightness, or perhaps just said "I know for these materials with these pressures this torque has served me well" I will add that what Colonel said bears note, I'm not aware if subsea applications have their own set torque methodologies.

If you are asking how much bolt load is put on the bolt by that torque, then you can refer to the calculations used previously (should be documented somewhere) to find the original target bolt load. From there you can factor in assembly methods and service life to see what the actual bolt load would or might be (and adjust installation practices accordingly).

Also going on what Colonel said, much more information is required on your part for anyone on here to be of help, when I help customers with torque, I have about 25 things I go over them with beforehand.

 

[DLite30]

For a start: See API 6A, Annex D.

 

[desertfox]

Hi SIAVASH54

A very rough estimate can be gained from:-

preload force = Torque/(0.2*bolt dia) 0.2= friction factor
for dry threads

From the formula I estimate a tensile preload of 16.4MN.

Really as others have said the joint materials, properties and stiffness of components need to be considered.

Try this site:-

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

desertfox

 

[unclesyd]

Torque values in foot pounds given for a 1-1/2" B7 stud with a 2H nut. The values given are for 100% yield.
The usual caveats apply as these values are for reference only.

BOLT DIAM 1-12"
NUT SIZE 2-3/8
MOLY LUBE 1674
NICKEL LUBE 2850
COPPER LUBE 2614
OIL 2614
DRY 3792