Assembly
20-00-02/70-00-01
C. Guideline - Assembly Torque Values (Nuts, Bolts, Screws, Studs, and Inserts)
NOTE: Table 507, Table 508, and Table 509 list assembly torque values based on service requirements for A286 heat-resisting alloy steel or equivalent fastener material with lubricated threads.
Torque values specified are in addition to frictional torques developed by self-locking devices.
Unless specified otherwise in tables, use nominal values as follow:
.
250 inch-pounds, ±5% (0 - 28.2462 N-m)
.
1200 inch-pounds, ±2.% (28.2462 - 135.58176 N-m)
.
Over 1200 inch-pounds, ±1% (Over 135.58176 N-m)
NOTE: Where two torque values are included, use the smaller one when the nut is torqued and the bolt is held stationary. Use the larger value when the bolt is torqued and the nut is held stationary.
Studs which have a different thread size on opposite ends shall be torqued to the smaller size regardless of which end is fitted into the installation.
When the use of Hylomar is specified, multi-bolted flanges shall be retorqued to original values after a 10-minute waiting period.
Application examples for Table 507, Table 508, and Table 509 torque values follow.
.
Table 507-Highly loaded connections; generally in specialized regions of the turbine such as steel-to-steel environment or joints directly exposed to rotor bearing dynamic forces. Specific applications include.
. Turbine plenum-diffuser flanges
. Turbine plenum-bearing flanges
. Turbine stator flanges
. Turbine bearing carrier-bearing capsule flanges
.
Table 508-Moderately loaded connections; generally aluminum joints, magnesium joints, aluminum or magnesium-to-steel joints in the compressor, gearbox, or accessory region of gas turbines. Some specific applications are.
. Diffuser-gearbox flanges
. Accessory cases-gearbox flanges
. Mounting flanges for accessories gearing
. Compressor, diffuser, and shroud flanges
.
Table 509—Lightly loaded connections; generally for clips and brackets. Torques may be used for nuts and a bolt installed on key- or ring-locked studs or inserts in magnesium for lightly loaded joints.
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