TORQUE & TENSION

WHAT IS TORQUE & TENSION?
Torque is the amount of force it takes to install and tension is the stretching of a bolt that provides the clamping force (clamp load).

WHY IS IT IMPORTANT?
When installing or assembling mating parts, it is pivotal to assemble the parts to the correct clamp load (or tension). The target clamp load (tension) for bolts is 75% of proof strength/load. The amount of torque necessary for fastener(s) to reach the target clamp load is dependent on the lubricating qualities of the finish on the fasteners. Under tightening can cause the excessive stretching of the fastener joint, causing the fastener to become loose over time and over tightening could increase the clamp load past the strength of the bolt causing it to break.
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The need for post lubricants has been eliminated due to the integrated lubricated built into RIE Coating’s top coats. These integrated friction modifiers ensure consistent assembly allowing the proper clamp load to be achieved.
How lubricious a coating is determined by coefficient, a dimensionless value. The lower this value is, the more lubricious the coating. Depending on the lubricating pigment and the concentration of the lubricant in each coating, RIE Coatings has coating options in a coefficient of friction range of 0.07 to 0.35
The correct amount of load ensures the fastened joint remains properly assembled. The standard deviation in input torque and/or clamp force is extremely low in comparison to zinc electroplating (see torque/tension PDF photos of test results). Inconsistent assembly can lead to under or overtightening.

The use of coatings with integrated lubrication reduces the amount of torque required for installation, allowing for easier assembly and can also prevent thread galling or seizing during installation.

HOW DOES RIE DIFFERENTIATE?
RIE Coatings customizes coatings for applications that have a specific coefficient of friction. Our test lab provides us the ability to measure torque, tension, k-factor and total coefficient of friction to ensure the coating process meets end user requirements.