New Techniques for the Quantification of Defects Through Pulsed Magnetic Flux Leakage

Although the probability of defect detection using magnetic flux leakage (MFL) inspection is sufficient for most applications for which it is used; inspection of ferromagnetic pipeline, wire rope, etc., accurate defect characterisation is problematic. The use of pulsed excitation in conjunction with MFL provides an opportunity for the extraction of depth information from the MFL signal using analysis of the transient section of the induced signal. This paper explores the use of pulsed magnetic flux leakage (PMFL) for the detection and quantification of defects in rolled steel water pipeline. For the newly developed PMFL system described in this paper, the time-frequency analysis employed in previous work is extended to look at shape features such as skewness. The paper concludes that PMFL can provide enhanced defect characterisation capabilities for flux leakage based inspection systems and could form the foundation of a fully automated defect characterisation system for pipeline inspection.