Munich/Mannheim - Innovative component shapes and modern materials are challenging the owners and designers of industrial equipment and facilities as non-destructive testing must be performed on increasingly complex components. To master these complex tasks, TÜV SÜD has developed a method based on high-tech ultrasound tomography. The results obtained with this method enable false positive results to be identified with greater reliability than in the past.
"Some of the valves and components that are replaced because of the results of conventional test methods are later found to be in perfect order", says Hans Christian Schröder, Manager Power Station and Energy Services at TÜV SÜD Industrie Service GmbH. "The NDT methods based on radiographic and ultrasonic testing that have been used in the past are increasingly coming up against their limits when applied to thick-walled components or nickel-based alloys." The problems occur when the paths of the probes or the scattering of the ultrasound signal are restricted by the design of a part or by components in its material such as nickel.
Parts and components such as industry valves, pressurised pipes or steam boilers must be inspected before they are placed into service and at regular intervals thereafter. "Our test system supports innovative component design and savings in materials, as test-friendly designs now need less space for the application of the test device", explains TÜV SÜD designer and developer Jörg Schenkel. "An additional advantage is that the test system now permits plant owners to clarify unclear results without having to shut down the system or plant as in the past." The system also provides more reliable determination of the remaining service life of a component.
The innovative test system was developed by a cooperation between TÜV SÜD, Fraunhofer IZFP and I-Deal-Technologies, Saarbrücken. It comprises a manipulator, the ultrasonic unit (sampling phased array) and a PC with visualisation software. The system provides for real-time image reconstruction in 3D even at high test speeds. The method can be used for quality assurance or as an alternative to radiographic testing – in particular if correct assessment of imperfections is of the essence.