Torque load diagrams

It has become more and more important to have good control of the torque-clamp load relationship when tightening a joint. To optimize the design of the joint and utilize as much of the capacity of each dimension as possible, you need to know the required tightening torque to obtain the desired clamp load with a minimum of deviation.

In our test laboratory we perform torque load tests that are corresponding to our customers specific design conditions. Due to the fact that the clamp load of the joint depends on the friction between the sliding surfaces, you will receive different clamp loads depending on the surface conditions.

This diagram shows the deviation in clamp load when not using any washer. When applying the same tightening torque you will receive different clamp load values depending on the material you are tightening against (aluminium or steel). Because of the higher friction when tightening against aluminium the clamp load will be much lower.

When using NORD-LOCK washers sliding will always occur between the same surfaces, i.e. between the washer and the head of the bolt, with the same surface conditions. You will receive a clamp load with a minimum of deviation.