Torque capacity of bolted flange
Torque capacity of bolted flange
(OP)
I am trying to confirm how to calculate the approximate torque capacity of a bolted flange. First you take the preload (P) that is generated by a bolt that is torqued to a certain amount. You then multiple P times the number of bolts in the bolt pattern to find the total preload. With the total preload you find the force (F) it takes to slide the two steel faces by F = ?*P with ? being the friction coefficient for steel on steel. With F calculated you take the radius of the bolt circle to find the Torque capacity.
Example:
12 3/4-10UNC Grade 8 bolts torqued give a preload of ~28,200 lbs. per bolt. 12 x 28,200 = 338,400 lbs.
Bolt circle is 9.88" diameter, ? for steel on steel is about 0.8, thus the torque capacity is about 1.3 million lb-in.
Is this correct?
Thanks
Example:
12 3/4-10UNC Grade 8 bolts torqued give a preload of ~28,200 lbs. per bolt. 12 x 28,200 = 338,400 lbs.
Bolt circle is 9.88" diameter, ? for steel on steel is about 0.8, thus the torque capacity is about 1.3 million lb-in.
Is this correct?
Thanks





RE: Torque capacity of bolted flange
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Torque capacity of bolted flange
Your concept is correct, but ? should be according to lubricaction condition between 0.15 to 0.25
RE: Torque capacity of bolted flange
RE: Torque capacity of bolted flange
Thread404-68353
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.