Bolt Tightening Torque 1

[moizpk2001]

I need to tight bolt (ASTM A 193 B8) with nut (ASTM A 194 B8).
Can any body help me to provide the torque table for various sizes of bolts of the above material combination.

Moiz Khan

 

[CoryPad]

It varies with lubrication conditions.

Some references:

faq725-536

MIL-HDBK-60 Threaded fasteners - tightening to proper tension, available for free at ASSIST:

http://assist.daps.dla.mil/quicksearch/

 

[vesselfab]

and coating on stud

 

[rlee629]

The torque for the various sizes can be found @

http://www.fastenal.com/content/feds/pdf/Torque of Stainless Steel, Non ferrous Torque.pdf

 

[Dinosaur]

How long is the grip of the bolt? Based on that, I could recommend a specific number of turns of the nut. How much tension do you want to develop?

 

[gtaw]

Why not use a tensioning device such as a Skidmore-Wilhelm gage to determine the proper torque values by testing a sample?

As long as the bolts are in a similar condition, i.e., lubrication, fit of the nut (thread class), etc. you would have a rational basis of the tension to torque values.

Best regards - Al

 

[stanweld]

The matching alloy nut is not the best idea if you ever want to remove it.

 

[tothepoint]

You also need to make sure that you develop sufficient assembly load for the gasket. The B8 bolt you mention (I assume class 1) is a low strength bolt, which will not deliver the necessary minimum gasket assembly stress in many ASME flanges- especially class 150.