2004•Insight - Non-Destructive Testing and Condition MonitoringRequires access
A radiographic calibration method for eddy current testing of heat exchanger tubes
Amir Movafeghi, Mohammad H. Kargarnovin, Hamid Soltanian‐Zadeh, Kaveh Edalati, B. Rokrok, A. Kermani, Masoud Seidi
Open publisher page 5 citations
Abstract
The most technically available NDT method for in-service inspection of heat exchanger tubes is eddy current testing. Using a differential ID bobbin probe, tubes can be tested with high speed, but for accurate estimation of tube condition, precisely machined calibration blocks from the same material are necessary. The purpose of this work was to calibrate the eddy current system by radiography without the use of expensive calibration blocks. Wall thickness measurement and deterioration determination due to corrosion/erosion/pitting was evaluated in this study by using radiograph ie film density measurements. It was found that this method can determine the remaining wall thickness as well as pitting corrosion in the tubes using differential and absolute film density measurements. Results show that good precision can be obtained with this method of eddy current system calibration.