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:
F = Bolt pre-load, (lbs)
k = Nut Factor based on lubricant used
d = Nominal bolt diameter, (in.)
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
- Bolting torque to develop 70% 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 1½ in. diameter are based on 30 ksi yield strength.
OTHER BOLTING TORQUE TABLES
BOLTING TORQUE TABLE 1 - ASTM A193 AND ASTM A320 GRADE B8, CL2 STUD BOLTS
BOLTING TORQUE TABLE 2 - ASTM 193 GRADE B7 AND ASTM 193 GRADE B16 STUD BOLTS
BOLTING TORQUE TABLE 2A - COLD SERVICE ASTM A320 GRADE L7 STUD BOLTS
BOLTING TORQUE TABLE 3 - USE ONLY WITH A193 B8, CL1 BOLTS AT 540°C - 650°C ON UNINSULATED FLANGES
BOLTING TORQUE TABLE 4 - USE ONLY WITH 6061-T6 ALUMINIUM FLANGES
BOLTING TORQUE TABLE 5 - PTFE COATED ASTM A193 B7 & ASTM 193 B16 STUD BOLTS
BOLTING TORQUE TABLE 5A - COLD SERVICE PTFE COATED ASTM A320 GRADE L7 STUD BOLTS