What is torqueing sequence?

What is torqueing sequence?

Bolt tightening sequence or torque sequence is defined in the torque tightening procedure. The torque value is dependent on the friction between the threads of stud bolt and nut head, this friction can be affected by the application of a lubricant or any plating (e.g. Cadmium or Zinc) applied to the stud threads.

What is a 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.

How do you tighten a 12 flange bolt?

1. First time around just snug the nuts with a hand wrench.
2. Second time around tighten the nuts firmly with the same wrench.
3. Third time around apply approximately 25% recommended torque.
4. Fourth time apply approximately 75% of recommended torque.
5. Fifth time around, apply 100% of recommended torque.

How important is torque sequence?

It’s the order in which you tighten the fasteners for a specific part, such as cylinder head bolts in an engine. It matters because it keeps pressure applied as evenly as possible so as not to warp parts or overstress the fasteners.

How many bolts are in a tightening sequence?

The crew members who do the tightening then simply follow the right numerical sequence (bolts 1,2,3,4 etc). In the case of very large flanges such as on 48-bolt flanges the process can be different. Here, groups of 4 adjacent bolts can be treated as ‘1 bolt’, resulting in 12 groups.

Which is the correct way to tighten a bolt?

Pass 1C – Tighten the rest of the bolts in the pattern to 100% of your final torque. You’ll continue applying torque on the bolt immediately to the right of the previously tightened bolt, following the pattern while working all the way around the flange.

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,…

Which is the correct order to tighten flanges?

The first thing you do is tighten each flange bolt between 20% and 30% of your target ft-lbs in the star pattern. The pattern itself is to apply to bolts #1-4 below (in order): …then move to bolts 5-8, again, applying torque in order: …and to complete this first step, you apply to bolts 9-12: