A 3-D Imaging Method for Local Shallow Defects on the Surface of Ferromagnetic Materials

Wang, Wenzhi; Huang, Songling; Zhao, Wei

doi:10.1109/tim.2021.3058992

Cited by 4 publications

(1 citation statement)

References 17 publications

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“…The slope of the fitted curve for the radial component change is greater than the slope of the fitted curve for the axial component at the time of the change in the lift-off value, and the radial component change is more pronounced. The experimental results of magnetic signal acquisition with different lift-off values show a consistent trend with the experimental results in [38,39], which verifies the correctness of the theoretical model.…”

Section: Spatial Distribution Of the Leakage Signal For Different Val...supporting

confidence: 83%

Study of MFL signal identification in pipelines based on non-uniform magnetic charge distribution patterns

Liu¹,

Lian²,

Liu³

et al. 2023

Meas. Sci. Technol.

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Magnetic flux leakage (MFL), a pipeline internal detection, is the mainstream technology for international oil and gas pipeline safety maintenance. To address the problem of large errors in the assessment of defects in pipeline inspection by existing theoretical analysis models, this paper introduces the charge density parameter to establish a mathematical model of non-uniform magnetic charge for pipeline leakage detection and calculates the non-uniform distribution pattern of magnetic charge on the defect side wall. The contour plot method is proposed to visually analyze the size of defects. To compare the error between uniform and non-uniform models, and verify the correctness of the theoretical model, experiments were systematically conducted on the X70 pipeline with internal MFL technology. The results show that: the magnetic charge distribution curve is symmetrically shaped at the center of the defect, with a valley at the center and two peaks at the defect edge. As the defect depth and width increase, the magnetic charge density increases sharply near the surface and edge. The peak-to-valley spacing and peak-to-valley values in the contour map of the magnetic flux leakage signal can directly reflect the location and size of defects. The signal characteristic values follow the trend of a first-order decreasing exponential function as the value of the lift-off increases. The first-order derivative of the signal characteristic value tends to decrease and then increase as the mesh size decreases, and the extreme point of the derivative curve is the best mesh size.

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Section: Spatial Distribution Of the Leakage Signal For Different Val...supporting

confidence: 83%