Applicable methods for NDT of tubes

Jorma Pitkänen, Aarne Lipponen, Pentti Kauppinen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


For inside inspection of tubes, eddy current testing (ET) and internal rotating ultrasonic inspection (IRIS) are mainly used at the moment. Special eddy current method, remote field technique (RFEC) is being used to some extent, but normally only for ferritic tubes. This paper presents a review of techniques that can be used for internal inspections of tubes in boilers, heat exchangers and steam generators. Material affects the choice of the method, considering given defect type and detectability with the selected technique. In general ET methods are used for inspection of non-ferromagnetic tubes and IRIS and RFEC methods for inspection of ferromagnetic tubes. New techniques have been introduced, to determine the tube condition accurately. One of the developed techniques is for instance inspection of the internal surface by combination of dye penetrant and optical laser inspection. New applications of ultrasonic techniques include defect detection and characterisation by tip diffraction echoes, defect analysis by echo dynamics and the TOFD-technique for defect sizing. Ultrasonic guided waves have a great potential to increase inspection speed for defect detection, although sizing is still under development. For inspection of ferromagnetic tubes, a method based on magnetic flux leakage has been used. In addition to the basic techniques visualisation of the measured data is one of the key factors for improved exploitation of the inspection results.
Original languageEnglish
Title of host publicationBALTICA VI - Life management and maintenance for power plants. Vol. 2
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
ISBN (Electronic)951-38-6294-1
ISBN (Print)951-38-6293-3
Publication statusPublished - 2004
MoE publication typeB3 Non-refereed article in conference proceedings
EventBALTICA VI - Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
Duration: 8 Jun 200410 Jun 2004

Publication series

SeriesVTT Symposium


ConferenceBALTICA VI - Life Management and Maintenance for Power Plants


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