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On-site evaluation of large components using SAFT and TOFD ultrasonic imaging

Vor-Ort Bewertung großer Bauteile mittels SAFT und TOFD Ultraschall-Bildgebung
: Spies, M.; Rieder, H.; Dillhöfer, A.

Thompson, D.O. ; American Institute of Physics -AIP-, New York:
Review of progress in quantitative nondestructive evaluation : San Diego, California, 18-23 July 2010, Volume 30A, Volume 30B
New York, N.Y.: AIP Press, 2011 (AIP Conference Proceedings 1335)
ISBN: 978-0-7354-0888-3
ISSN: 0094-243X
Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) <37, 2010, San Diego/Calif.>
Fraunhofer ITWM ()
imaging; ultrasonic; defect; simulation; validation; weld; pipe

The safe operation of transportation vehicles such as ships and ferries requires inspection of the highly stressed parts and components. The same holds for other safety relevant constructions such as pipelines where emphasis is on quality assurance prior to the final installation. Failure of such components can lead to serious environmental as well as economic damage. In this contribution we concentrate on ultrasonic inspection and evaluation of welds in such large components. The most endangered part of ships is the propeller. Therefore a solution has been developed in order to enhance the reliability of welded propellers and to extend the scope of repairable blade damages in order to avoid long term restrictions until a spare propeller is available. The Synthetic Aperture Focusing Techni que (SAFT) has been modified to cope with the curved surfaces and the sound attenuation of cast Ni-Al bronzes. Using mechanized scanning ultrasonic evaluation has been optimized in view of the least detectable defect sizes. For weld inspection in steels the Time-of-Flight Diffraction technique (TOFD) can provide additional information for specific defect orientations. We have therefore combined both techniques in view of the determination of defect sizes and shapes in longitudinal welds of pipes with diameters of up to 48 inches. We present details on the inspection and evaluation concepts as well as experimental results obtained on test specimens during the validation process. For on-site inspection in dry-dock or at the manufacturing sites, mobile equipment has been design and build-up; respective inspection actions and results will be presented as well.