Bolt make-up — torque calculator
Torque-vs-preload (Shigley short-form)
T = K · F · d. Compute required torque for a target preload + verify it's enough to seat the gasket against the hydrostatic end-load. Standard for ANSI B16.5 flanges with 8-12 bolt patterns.
Inputs
%
ASME PCC-1: target 70-75 % yield · machine-designs 65-90 %
bar
mm
Roughly the mean of inner + outer gasket diameter
ASTM A193 / SA-193 B7 — workhorse · typical industrial
Results
Bolt 3/4-10 tensile area A_t216mm²
Preload F_p117178N
Preload F_p26342lbf
Torque T (T = K·F·d)402N·m
Torque T296lbf·ft
Hydrostatic end-load70686N
Required preload per bolt8836N
Preload margin1226 %
VerdictCONSERVATIVE — high preload margin
T = K·F·d is the simplified Shigley short-form. For higher accuracy use the long-form (Friction Coefficient × thread angle × pitch), ASME PCC-1 Annex K calibrated values, or hydraulic-tensioner load cells. Always cross-tighten flange bolts in 4-pass star pattern.
Download all inputs + calculations + outputs as a single PDF.