Remote field eddy current testing for detection of stress corrosion cracks in gas transmission pipelines

Magnetic flux leakage (MFL) pigs are traditionally used for the detection of gross corrosion on steel pipelines used for the transmission of natural gas. Alternative nondestructive evaluation (NDE) modalities are required for the detection of stress corrosion cracking (SCC), which tends to exist in colonies oriented axially along the length of the pipeline. This paper describes the use of multi-phase rotating magnetic fields in the remote region of the probe as a possible SCC detection mechanism. Details of a prototype pig and test rig are given and the challenges associated with the finite element modeling of the device are discussed. Initial experimental results show that this novel NDE modality is sensitive to axially oriented tight cracks. [Copyright &y& Elsevier]