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Well Testing Toolbox

Interactive Tools

Engineering calculators and conversion utilities for field work.

Recommended Flange Bolt Torque

Calculate required torque based on stud diameter, pitch, and desired bolt stress.

Stud Diameter (D) (in)

Threads per inch (N)

Bolt Stress (σ) (psi)

Friction Coeff. (f)

Torque Equation

$$A_s = \frac{\pi}{4} [D - (0.9743 \times P)]^2$$ $$T = \frac{F \cdot E \left( P + \pi f E S \right)}{2 \left( \pi E - P f S \right)} + F f \left( \frac{H + D + K}{4} \right)$$

Tension Force (F) (lbf)

Required Torque (T) (ft-lbf)

API Flange Torque Master Chart

Stud Dia (in)	Threads (N)	40 ksi (ft-lb)	52.5 ksi (ft-lb)	47.5 ksi (ft-lb)