6.Torque
bolts in a minimum of four stages as listed in Steps
7, 8, 9, and 10 below.
7. 7.Torque
the bolts up to a maximum of thirty percent of the
final torque value required following the sequence
recommended. (See charts for bolting sequence.)
Number bolts so that torquing requirements can be
followed. With any gasket material, it is extremely
important to follow a proper bolting sequence. If
this sequence is not followed, the flanges can be
cocked. Then, regardless of the amount of subsequent
torquing, they cannot be brought back parallel. This
problem, of course, is maximized on metallic gaskets
more so than on nonmetallic.
8. 8.Repeat
step 7, increasing the torque to approximately 60
percent of the final torque required.
9. 9.Repeat
step 8, increasing the torque to the final torque
value.
1
10.On
high-pressure, high-temperature applications, it is
suggested that the flanges be retightened to the
required stress after 24 hours at operating
pressures and temperatures to compensate for any
relaxation or creep that may have occurred.
>>The End
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