17/12/2011 · Bolt Torque. Torque is the turning force measured in footpounds (ftlb) or inchpounds (inlb) applied to tighten (turn) the nut on a bolt. Torque can be measured during flange assembly with a properly calibrated torque wrench. In a bolted flange, the applied torque generates the axial load in the bolt. The bolt acts like a spring.