The Challenge

The connection between the slewing ring and the portal requires very high precision during the tightening of the bolted connection. The pre-tensioning of the bolts often reaches a yield strength of 90%. However, when using conventional tightening methods, it is difficult to obtain this value precisely. Furthermore, the bolted connection could already get damaged during installation.

The Solution

Kirow Ardelt meets these high demands by using Superbolt tensioners. The precision of the pre-tension is regularly checked and maintains at ±2 %. Under extreme circumstances and with very little effort very high precision can be obtained during pre-tensioning.


According to type – 128–244 pcs. CY-M36…M42


A further advantage is that during periodic maintenance works the pre-load can be checked simply with the use of a torque wrench and therefore with very little effort. If necessary, the bolts can be retensioned at the same time.