Bolt torque calculation, lubrication factor, and nut factor to be determined in Appendix K of ASME PCC-1 2019.
__See formula (K-1) or (K-1M).
__Check flange rate and bolt size in Table L-1.
__Bolt stress determination in Appendix O. Normally bolt stress is approximately of 40-60% of yield strength, example ASTM A193 B7 – yield strength is 105ksi --> target bolt stress of 60% YS = 105*0.6 = 63ksi = 63x1000 = 63000 psi. Don’t worry no need to find root areas, bolt size and K factors. See Table O-3.2-1.
__Calculation target bolt torque Tb – see note (b) of Table O-3.2-1 (ft-lb)
____Example, See Table O-3.2-1 for Flange NPS ½”, nut factor K=0.2 (k=0.2), bolt material ASTM A193 B7 (check yield strength in Table 2 of ASME SA-193 2019 --> Bolt stress = 10560/100 = 63ksi) => Tb = 631.05 = 66 ft-lb.
__Next double check determination of bolt stress see example O-4.3 in ASME PCC-1 2019.
SI Unit see Table O-3.2-1M.
Bolt marking Bolt And Nut Identification – Marking Identification.