Bolt tensioning

In the bolt-tensioning process, the bolts are stretched axially using hydraulic bolt-tensioning tools, and the nut is then applied by hand. This process generates neither torsional forces in the bolts nor frictional forces in the thread or between the nut and the flange surface. Bolt tensioning is a ‘wear-free’ tightening method in which seizing between the nut and the bolt thread is technically impossible! To ensure the quickest possible assembly and uniform seating of the gasket, a tool is fitted to at least every second bolt and tightened simultaneously. The installation bolt torque must be specified by the operator or will be calculated by us (see also Engineering Services – flange calculations)

We work with both single-stage and two-stage pull cylinders.

Our units operate at pressures of up to 2,500 bar and are therefore capable of applying very high preload forces. Following each flange assembly, you will receive the relevant report as proof.