Home - www.wermac.orgsearch wermac.org
www.wermac.org
Flange Guide

Flange Bolt-Up Bolting Torque Table 1

The torque tables are built on specific assumptions regarding bolt and nut factor. Before using a given torque table, these assumptions should be verified to insure they are appropriate for the specific application.

Even if all assumptions are appropriate, results may vary depending on actual conditions. Many factors induce scatter in the results or increase the inherent variability in the bolting process. These include variations in the nut factor; bolt, flange and nut condition; equipment calibration and condition; perpendicularity of the bolt, nut and flange; etc.

The values in the tables are based on the equation:

Bolting Torque
T = Torque value, (ft-lbs)
F = Bolt pre-load, (lbs)
k = Nut Factor based on lubricant used
d = Nominal bolt diameter, (in.)
Hydraulic Torque Wrench

The nut factor is not the coefficient of friction.
It is an experimentally derived constant that includes the impact of friction.

ft-lbs to nm = 0.737562149277
nm to ft-lbs = 1.3558179

Table 1 / Torque FT-LBS - ASTM A193 and ASTM A320 Grade B8, CL2 Stud Bolts
BOLT
DIA
Torque FT-LBS
30% Initial
Torque
70%
Torque
100% Final
Torque
1/2 16 36 52
9/16 23 53 75
5/8 31 73 104
3/4 55 129 184
7/8 71 166 237
1 107 249 356
1.1/8 127 297 424
1.1/4 179 417 596
1.3/8 186 435 622
1.1/2 246 574 821
1.9/16 168 392 560
1.5/8 191 445 636
1.3/4 240 561 801
1.7/8 298 696 994
2 366 853 1219
2.1/4 529 1234 1762
2.1/2 733 1709 2442
2.3/4 986 2300 3285
3 1289 3008 4297
Table 1 / Torque Nm - ASTM A193 and ASTM A320 Grade B8, CL2 Stud Bolts
BOLT
DIA
Torque Nm
30% Initial
Torque
70%
Torque
100% Final
Torque
1/2 22 49 71
9/16 31 72 102
5/8 42 99 141
3/4 75 175 249
7/8 96 225 321
1 145 338 483
1.1/8 172 403 575
1.1/4 243 565 808
1.3/8 252 590 843
1.1/2 334 778 1113
1.9/16 228 531 759
1.5/8 259 603 862
1.3/4 325 761 1086
1.7/8 404 944 1348
2 496 1157 1653
2.1/4 717 1673 2389
2.1/2 994 2317 3311
2.3/4 1337 3118 4454
3 1748 4078 5826

Notes:

  • Bolting torque to develop 50% Bolt Yield Stress at Nut Factor, K=0.16
  • This Table is applicable to Never-Seize paste and Fel-Pro lubricant, K=0.16.
  • The above Table is applicable only for ASTM A320 Grade B8, Class 2 and A193 Grade B8, Class 2 Stud Bolts. These are 304 SS material.
  • The torque values are approved for spiral wound graphite and PTFE filled gaskets, graphite sheet gaskets GHE and GHR types, ring joint, double jacketed and Camprofile gaskets.
  • The Final Torque Value accounts for 10% bolt relaxation.
  • The yield strength for strain-hardened bolts varies with diameter. Torque values for bolts greater than 1.1/2 in. diameter are based on 30 ksi yield strength.
PP
Close

^