What is the correct order for tightening bolts on a flange?
What is the correct order for tightening bolts on a flange?
Tightening sequence 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.
How do you torque a flange bolt?
Tighten each fastener in two steps. First to half torque and second to final torque. Put the socket on the head of the wrench. Turn the nut by hand until it catches the screw threading.
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 flange bolt torque tightening procedure?
Most company has their Flange bolt torque tightening procedure that used during construction and operation of the plant. Flange joints are torque tight with the help of a torque wrench (Manual or hydronic wrench). The clamp load produced during tightening is higher than 75% of the fastener’s proof load.
What is torque sequence in torque tightening procedure?
Bolt tightening sequence or torque sequence is defined in torque tightening procedure. Most company has their Flange bolt torque tightening procedure that used during construction and operation of the plant. Flange joints are torque tight with the help of a torque wrench (Manual or hydronic wrench).
How do I tighten the flange?
If an air wrench is used make sure the pressure is set to the minimum. When tightening, always use the correct sequential bolt order for the flange. One final time – clockwise or counter clockwise sequentially around the flange.
What is the purpose of bolt tightening?
Proper bolt tightening will ensure uniform load distribution in all bolts without damaging the gaskets. The following procedure describes how to tighten flange bolts. Before actual tightening starts, the flange, gasket, bolts/nuts need to be observed as below:
