# How do you calculate bolt tension?

## How do you calculate bolt tension?

The Torque/Tension Equation is a method used to estimate the torque/tension relationship in an assembly. T = (K D P)/12 can be used to developt a torque value that will achieve a certain tension or clamp load. T = Torque (ft. -lbs.)

What is Hydraulic bolt tensioning?

A hydraulic bolt tensioning tool provides a quick and easy method for tightening large diameter bolts to high and accurate pre-loads. Unlike conventional methods it does not use torque and does not require any forceful turning of the nut or bolt, like impact wrenches, flogging spanners or hydraulic torque wrenches.

What is the difference between torquing and tensioning?

“Torque” is simply a measurement of the twisting force required to spin the nut up along the threads of a bolt, whereas “Tension” is the stretch or elongation of a bolt that provides the clamping force of a joint. Torque wrenches provide this tension by the amount of rotational force they apply to the bolt.

### How do you tension a flange?

Tensioning operation

1. Step 1: The bolt tensioner is fitted over the stud.
2. Step 2: Hydraulic pressure is applied to the tensioner which then stretches the stud.
3. Step 3: The stud’s nut is wound down against the joint face.
4. Step 4: Pressure is released and the tool removed.

How do I know if I need a clamp load?

Clamp load (lb.) is calculated by arbitrarily assuming usable bolt strength is 75% of bolt proof load (psi) times tensile stress area (sq. in.) of threaded section of each bolt size. Higher or lower values of clamp load can be used depending on the application require- ments and the judgement of the designer.

Why bolt tensioning is required?

The objective of tensioning is to stretch the bolt, or stud, to a predetermined load, by using force to elongate the shank. Very little turning force is required. It is necessary to have some extra thread above the nut, which is used to attach the pulling cylinder, which is removed after completion.

## What does torquing a bolt do?

Torque tightening is the accurate application of torque to a nut so that a bolt can hold its load securely without breaking. Too much torque can break the bolt. When you apply the right amount of torque, the bolt is properly stretched so that it can act as a solid spring to clamp the two materials together.

Why is bolt torquing needed?

Torque is used to create tension. Bolts are used to affix two components so that they can resist tensile (pulling apart) and shearing (sliding apart) forces. After the nut has been turned onto the bolt, additional torque causes the nut to turn and stretch the bolt.

How much force can a bolt take?

Steel bolts are graded according to newtons per millimeter squared for bolt tensile strength as compared to yield strength. For example, a steel bolt with a rating of 5.5 will provide roughly 500 newtons/mm2 of bolt tensile strength and approximately 400 newtons/mm2 of yield strength.

### How much force can a bolt exert?

Tensile strength (min psi) of all Grade 7 bolts is 133,000. Proof load is 105,000 psi. 4. Tensile strength (min psi) of all Grade 8 bolts is 150,000 psi.