What is the torque sequence?
Bolt tightening sequence, or torque sequence, is defined in the torque tightening procedure. Flange joints are torqued tight with the help of a torque wrench (manual or hydraulic). Torque bolts and nuts in a “CRISS-CROSS” sequence using a minimum of three torquing passes and the maximum bolt stress as defined.
What is the torque sequence and torque?
Torque sequence refers ro the pattern in which you tighten the bolts. The overall goal is to spread the torque evenly as you are tightening the bolts. Usually, you start at one bolt, and you work your way around in a circular pattern. Doing so ensures that your head won’t be warped during the tightening sequence.
What is the tightening sequence?
Bolt tightening sequences are when an arrange of bolts are tightened in a pattern to the required torque. The sequence the bolts are tightened is a symmetrical pattern to reduce the amount of pre-load lost in a bolt, as a result of elastic interactions. Torque is normally applied to a bolt using a torque wrench.
How is torque pattern calculated?
Begin with the formula T = K x U x D x P, where T is the torque, K is a standard representing 1.33, U is the coefficient of friction, D is the diameter of the fasteners, and P is the necessary preload.
What is star pattern for tightening bolts?
For all 5-bolt parts, you’ll want to tighten them down using a “star” pattern. Starting at top-dead-center, tighten the first bolt until it’s just begun to tighten. Going clockwise or counterclockwise, skip the next bolt, and repeat the process. Keep tightening every-other bolt until all five are slightly tight.
Which is the correct torque sequence for a flange bolt?
Flange Bolt Torque Sequence. PASS 2: Torque to a maximum of 60% of the final torque value. PASS 3: Torque to the final torque value (100%). After the three basic torque passes are completed, repeat torquing the nuts at least once using the final torque in a “CRISS-CROSS” manner until no further rotation of the nut is observed. For easy handling,…
When to use Torquing on a flange bolt?
When the bolt loading requires a torque higher than 678 Nm (500 ft-lbs.) to be applied, hydraulic bolt torquing is recommended.
How many torquing passes in a criss-cross torque sequence?
Torque bolts and nuts in a “CRISS-CROSS” sequence using a minimum of three torquing passes and the maximum bolt stress as defined. PASS 1 Torque Sequence: Torque to a maximum of 30% of the final torque value in accordance with the torque sequence.
What are the ratings of a flange bolt?
The information in this app covers: (1) flanges with rating class designations 150, 300, 400, 600, 900, and 1500 in sizes NPS 1/2 through NPS 24 and flanges with rating class designation 2500 in sizes NPS 1/2 through NPS 12, with requirements given in U.S. Customary units with diameter of bolts and flange bolt holes expressed in inch units;