Quantitative study of pipe stripe defects using rotating magnetic field MFL

Addressing the challenges of difficult detection and low identification accuracy for stripe defects (including axial and circumferential defects) on the outer wall of oil pipes, this paper proposes a novel nondestructive testing method based on a rotating magnetic field. This method employs rotating magnetic field excitation for dynamic magnetization of the pipe. By utilizing simulation calculations and analyzing the magnetic flux leakage signal’s features at defect locations with Empirical Mode Decomposition–Fast Fourier Transform (EMD-FFT), identification rules for the circumferential width and radial depth of stripe defects are summarized, achieving precise characterization of these defects. This provides a new approach for the accurate quantification of stripe defects on the exterior of pipelines and offers a novel methodology for the further development of measurement instruments capable of accurately identifying pipeline stripe defects.