Friction Factor to use in bolt torque formula 1

[MalcolmA]

I am using a Nickel Anti-Seize thread lubricant on the studs of a flanged joint. I am trying to calculate the target torque to achieve the desired bolt stress. I am having trouble determining the proper coefficient of friction to use in the formula. The product data sheet for the particlar lubricant that I am using lists two coefficients of friction:

"K" factor (static) 0.18
ASTM D 2266 (dynamic) 0.12

Can anyone tell me what is the correct friction factor to use?

 

[bernoullies123]

Suggest having a look through the newly revised Guidelines for Pressure Boundary Bolted Flange Joint Assembly published by ASME PCC-1-2010.

Table 1/1M provides Target Torque values for non and coated bolts for a number of bolt sizes. These values are based on K of 0.16 & 0.12 for non & coated surfaces respectively in either units.

The commentary of this is provided in Appendix K Nut Factor Calculation of Target Torque. An interesting note is that the nut factors can be evaluted relatively easily by measuring the obtained bolt load by means of ultrasonics, load cell, or pressure increase with a hydraulic tensioner.

AMSE just published an article on the new revision here:

http://memagazine.asme.org/Articles/2010/July/Assembling_Knowledge.cfm