In-Service Phased Array Inspection of Slew Bearing Rings

ITS has gained quite some experience when it comes to examining the raceways of slew bearing rings while in-service, so without the need for disassembling anything or causing lengthy delays.

Slewing bearing rings are essential components of conventional cranes, but being critical parts of major weightlifting, flaws can emerge. Slew bearings can suffer from fatigue stress, leading to cracking in critical, high stress areas. Our inspection capabilities allow us to reach predetermined areas of interest and detect defects efficiently.

PAUT inspection process and application

To detect and size critical fatigue cracks early ITS uses specific phased array probes. The complex geometry and expected orientation of defects require a specialized inspection procedure. Prior to testing, ITS will review the OEM drawings to assess the inspectability.

To do so, firstly a cross section of the slew bearing ring raceway(s) is drawn using known details or construction drawings. Then all the areas of interest are defined as per client specification. When the geometry is outlined and the areas under test are known we use special simulation software to generate the most ideal phased array scan plan. Keeping in mind the scanning restrictions, such as; gear teeth, studs, sensors, lubrication channels, walkways, accessibility, etc, etc.

Such an inspection, excluding the preparation time, is usually carried out in a single day. Thus, minimizing any downtime.

Advantages of performing the inspection

  • Disassembly of components is not required
  • In-service inspection
  • Permanent recording of inspection results
  • Monitoring of defects

Required preparation

  • (Construction) drawings of the slew bearing ring to assess the inspectablity
  • Safe access to the inner and outer bearing ring components
  • Examination surface must be free of coating
  • Fresh water supply in the vicinity
  • Customer safety requirements on the vessel
  • Any legal/regulatory safety requirements

Reporting of findings

After the field data is collected, the data will be analyzed. The inspection report will contain the key results and findings. Accompanied by, if applicable, screenshots of the detected defects with estimations of depth and length so its severity can be assessed.

For more information, feel free to contact us.