How do you sequence torque flange bolts?

How do you sequence torque flange bolts?

The first pass, lightly tighten the first bolt then move directly across or 180 degrees for the second bolt, then move1/4 turn around the circle or 90 degrees for the third bolt and directly across for the fourth. Continue this sequence until all bolts are tightened.

What is the torque sequence pattern?

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). The clamp load produced during tightening is higher than 75% of the fastener’s proof load.

How do you torque a flange?

Ensuring proper flange alignment….First to half torque and second to final torque.

1. Put the socket on the head of the wrench.
2. Turn the nut by hand until it catches the screw threading.
3. Turn the handle clockwise to tighten the nut.
4. Stop turning the wrench when it stops clicking or moving.

Why is torque sequencing used on flanges?

Flange joints require proper tightening to avoid the leak of the fluid from the joint. Bolt tightening sequence or torque sequence is defined in the torque tightening procedure. Most company has their Flange bolt torque tightening procedure that used during construction and operation of the plant.

What general sequence should be used when tightening a series of bolts or nuts?

When there is a requirement of tightening of a number of bolts and nuts in a series, to make the part component get set down evenly and avoid distortions, the fasteners must be tightened in a crisscross fashion. This ensures the even distribution of clamping force.

How is torque pattern determined?

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.

Why do we torque in a star pattern?

When tightening lug nuts, use the star pattern. This will assure the wheel is drawn down evenly and all the nuts equally torqued. The manufacturers torque specifications for your vehicle can be found online, in spec guides and even the owner’s manuals in many cases.

What is flange torque?

Bolt Torque is the twisting or turning force applied to tighten the nut on a bolt. Using a calibrated torque wrench (Manual or Hydraulic Torque Wrench), flange bolt torque can be measured during flange assembly. This torque creates an axial force in the bolt.

How tight should flange bolts be?

The toilet bolts should not be overtightened, but they should be tight. If you hear the sound of metal on porcelain, stop tightening. But if you still feel the bolts tightening against the wax ring, keep going.

What is the purpose of a torque sequence?

With such a sequence, each bolt is tightened more than once so as to reduce the preload reduction caused by the tightening of the other bolts in the joint.

Why do we use a sequence of tightening?

A good tightening sequence ensures that an even preload distribution is achieved in the joint (See Dia. A). Since joints containing conventional gaskets have a comparatively low compressive stiffness, bolt preloads in such joints are particularly sensitive to the tightening sequence.

What is the proper way to torque a bolt?

Place the socket and torque wrench on the fastener and tighten the bolt, holding the torque wrench by the handle at the end of the wrench. Rotate the torque wrench slowly and smoothly, continuing through the arc until the wrench clicks. The click indicates that you have reached the desired torque.

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 should be used to tighten flange bolts?

The bolts shall be tightened by torque control, using the Anti-seize lubricant shall be used such as Molykote or equivalent, before installation. The specified method of bolt tightening is equally applicable to coated, galvanized and ungalvanized bolts.