A Classification and Identification Method for Metal Conductor Surface and Subsurface Defects

Abstract

The invention belongs to the technical field of nondestructive testing, and relates to a method for classifying and identifying defects on the surface and subsurface of metal conductors. The detection probe used in the method includes an excitation coil, a giant magnetoresistance sensor and a permanent magnet, and the giant magnetoresistance sensor is fixed on the part of the excitation coil. At the bottom, the permanent magnet is fixed on the outside of the excitation coil. The method is: place the detection probe on the surface of the test piece, apply a sinusoidal signal to the excitation coil, move the detection probe to scan the test piece; Filtering and amplification processing; demodulate the output signal of the giant magnetoresistance sensor after filtering and amplification processing, obtain the real part and imaginary part, and obtain the amplitude and phase angle information; check whether the scanning position exists according to the amplitude and phase angle information Defects and defect types are judged. The invention can directly and quickly classify and identify defects, with obvious feature quantity and accurate identification.

Description

Technical field [0001] The invention belongs to the technical field of non-destructive testing, in particular to a method for classifying and identifying surface and subsurface defects. Background technique [0002] Non-destructive testing technology has a wide range of applications and is widely used in various fields of industrial production, such as electric power, oil and gas transmission, shipbuilding, aerospace, nuclear energy, and railway industries. It is of great significance to improve product stability, reliability, and safe operation. Eddy current testing is a widely used testing method because of its advantages of no couplant, non-contact, automatic testing, and high-temperature use. It has an important position and value in the field of non-destructive testing. [0003] At present, the classification and recognition of defects in eddy current testing is mainly to obtain the characteristics of defects through feature extraction methods, and on this basis, accord...

AI Technical Summary

Problems solved by technology

However, the above methods usually require a certain amount of calculation, the classification of defects is not intuitive, it is not easy to interpret and analyze the results, and there is a certain false detection rate, which does not fundamentally solve the problem of classification and identification of surface and sub-surface defects.

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