Method for characterizing defect width through magnetic flux leakage detection

Abstract

The invention discloses a method for characterizing defect width through magnetic flux leakage detection. According to the method, the defect width is represented by utilizing the axial distance between the extreme points of the axial magnetic flux leakage change rate, the influence degree of the lift-off distance on the axial magnetic flux leakage relative to the other two components is low fromthe perspective of the change rate of the signal, and the obtained defect width is relatively small in difference and relatively high in precision under different lift-off distances. The method is notinfluenced by the size of the defect depth and the fluctuation of the lift-off distance of the device in the signal acquisition process, and stably represents the defect width greater than max (x1, x2); as max (x1, x2) is small, the defect width below max (x1, x2) is qualitatively analyzed and calibrated as the small defect width, so that the method can calibrate the defect width more accuratelyunder the conditions that the defect width is unknown, the lift-off distance fluctuates within a certain range and the specific lift-off distance is unknown, the anti-interference capability is higher, and the implementation method is simpler.

Description

technical field [0001] The invention belongs to the field of magnetic flux leakage detection, in particular to a magnetic flux leakage detection method for characterizing the width of a defect in a ferromagnetic pipeline. Background technique [0002] Ferromagnetic material pipelines are widely used in industry, and most of the ferromagnetic metal pipelines are damaged rapidly due to their harsh service environment, which will cause leakage and explosion accidents in severe cases. [0003] Magnetic flux leakage detection has the advantages of simple automatic operation, high efficiency, and large detection depth. It occupies an important position in the existing ferromagnetic material defect detection. Magnetic flux leakage detection is to pick up the magnetic flux leakage signal caused by the change of magnetic permeability at the defect in the magnetically saturated tested part. At present, accurate identification of defect edges has always been the focus and difficulty ...

AI Technical Summary

Problems solved by technology

Existing studies have shown that the radial component of the pipeline is greatly affected by the lift-off distance, and the surface of the pipeline in service will be uneven, and the lift-off distance of the detection device will fluctuate during the detection process

Therefore, the above characterization method cannot accurately calibrate the defect width under different lift-off distances

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