An in-line inspection tool for the detection of stress corrosion cracking (SCC) and coating disbondment based on electro-magnetic acoustic transducers was developed, following a high-resolution approach. After having successfully tested this 16 inch EMAT Crack Detection (ECD) tool thoroughly in sample pipes containing real SCCs and various types of artificial defects, first runs were performed that proved the performance of the approach under operational conditions. The use of the EMAT technology was commissioned for the inspection of two 16 inch liquid and gas pipelines (arab light oil and sour gas) for detecting the occurrence of SCC and external coating disbondment. These two pipelines were specifically selected due the experienced presence of SCC and coating damage in them. The echo channels are sensitive to both defects in the axial and in the circumferential direction. Increased transmission signal amplitudes indicate areas of a weaker or even loose coating like at the beginning and the end of the welding joint. Both, pipeline and coating related features were found. The high-resolution approach revealed accurate results and still offers further potential for continuous improvements. The promising results of the first inspection survey are being further validated. The data evaluation can rely on multi-dimensional data-sets, which allows continuous improvement, on the basis of the scheduled validation program.
In-line inspection with high resolution EMAT technology crack detection and coating disbondment
Hochauflösende Ultraschallprüfung zur Feststellung von Spannungsrißkorrosion und Schichtablösung in verlegten Gas- und Ölpipelines
2007
7 Seiten, 6 Bilder, 1 Tabelle, 1 Quelle
Conference paper
Storage medium
English
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