Bolt Torque

on . Posted in Fastener

Torque, also called moment of force, is a rotational moment. It is a measure of how much twisting is applied to tighten (turn) the nut on a bolt.  When bolting flanges together or anything else tor that matter, tightening the nut stretches the bolt adding pressure to the gasket.  The bolt are designed to stretch a bit acting like a spring.  Different factors can affect the torque like number of threads, oil, rust, type of material, etc.


Bolt Torque formula

\(\large{ T = \frac {k\;d\;p} {12}  }\)
Symbol English Metric
\(\large{ T }\) = torque \(\large{lbf-ft}\) \(\large{N-m}\)
\(\large{ p }\) = desired clamp load tension \(\large{lbf}\) \(\large{N}\)
\(\large{ d }\) = nominal diameter \(\large{in}\) \(\large{mm}\)
\(\large{ k }\) = torque coefficient \(\large{dimensionless}\)


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Tags: Torque Equations