Anomalous Models of Defect Interactions in Electromagnetic Testing

Stress corrosion cracking (SCC) is a major concern in oil and gas transmission lines. Small external, axially aligned cracks are difficult to detect and size using present boreside inspection techniques. Remote field eddy current (RFEC) testing is an inspection technique for tubes currently in use for the inspection from well casings to small diameter heat exchange tubes. An advantage of this technique over conventional eddy current testing is its ability to detect both external and internal defects in ferromagnetic materials with approximately equal sensitivity. Because of RFEC’s proven sensitivity to external defects and the fact that eddy currents are induced in the circumferential direction, there is currently great interest in the technique for the inspection of pipelines