Investigations of magnetic flux leakage and magnetic Barkhausen noise signals from pipeline steel

• Published in: Journal of physics. D, Applied physics Vol. 30; no. 6; pp. 962 - 973
• Main Authors: Mandal, K, Dufour, D, Krause, T W, Atherton, D L
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 21.03.1997; Institute of Physics
• Subjects: Applied sciences; Crude oil, natural gas and petroleum products; Energy; Exact sciences and technology; Fuels; Gas industry; Gas transmission and distribution. Ships. Pipelines. Distribution networks. Compressors stations; Transportation and distribution of crude oils and liquid petroleum products. Ships. Pipelines. Terminals. Service stations; Gas pipeline; Magnetic leakage flux; Underground pipeline; Oil pipeline; Barkhausen effect; Transport; Leak detection; Natural gas; Petroleum; Defect detection
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/30/6/009

Magnetic flux leakage (MFL) is used for in-line inspection of underground oil and gas pipelines. MFL signals are sensitive to the line pressure which should be taken into account when estimating the sizes of defects. MFL signals have been studied from electrochemically milled pits with 50% penetration in pipeline steel under the influence of different axial or circumferential stresses and a range of magnetic flux densities. Magnetic Barkhausen noise (MBN) measurements have been used to study the changes in the direction of the magnetic easy axis of the pipe wall. These help one to understand the stress-dependent MFL results. MBN measurements have also been used to estimate the directional magnetic anisotropies of the steels.