Differential high-speed track defect detection method of compounding magnetic flux leakage with eddy current
A high-speed orbital, differential technology, applied in the fields of material magnetic variables, material analysis by electromagnetic means, instruments, etc., can solve the problems of limited eddy current detection, difficulty in detecting near-surface buried defects, inability to distinguish, etc. The probe structure is simplified, easy to implement, and there is no time delay effect
Active Publication Date: 2019-10-08
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology
Among them, magnetic flux leakage testing can detect surface opening defects and near-surface buried defects at the same time, but cannot distinguish between them
However, eddy current testing is limited by the skin effect, and it is difficult to detect buried defects near the surface after the frequency is increased.
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[0035] Embodiments of the invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.
[0036] Such as figure 1 Shown is a schematic diagram of the structure of the detection probe used in the method of the present invention. The probe includes a yoke 1, a yoke coil 2, and a differential detection coil 3. DC excitation is applied to the yoke coil 2, so that the measured area of the test piece 4 Magnetized to a saturated state, AC excitation is applied to the differential detection coil 3, and the differential detection coil 3 simultaneously detects the magnetic flux leakage signal and the eddy current signal at the defect.
[0037] Such as figure 2 As shown, it is a block diagram of the detection signal processing flow of the method of the present inve...
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The invention discloses a differential high-speed track defect detection method of compounding magnetic flux leakage with eddy current. A detection probe used in the method comprises a magnetic yoke,a magnetic yoke coil and a differential detection coil; DC is firstly introduced into the magnetic yoke coil to form a static magnetic field to make a detected object in magnetic saturation; single-frequency AC excitation is applied to the differential detection coil when the detected object is in the magnetic saturation state; and a bridge circuit detects a magnetic flux leakage signal and an eddy current signal. According to the method disclosed by the invention, a differential magnetic flux leakage signal and a differential eddy current signal are obtained through signal processing on the basis of fusion of a magnetic flux leakage detection method and an eddy current detection method, and the difference between the two signals is compared and analyzed, thereby achieving distinguishing of surface defects and buried defects. The method disclosed by the invention has the advantages of being non-contact, easy to implement, easy to operate and high in detection efficiency and is applicable to defect classification in online real-time detection of high-speed tracks.
Description
technical field [0001] The invention relates to a differential magnetic flux leakage and eddy current composite high-speed rail flaw detection method, which belongs to the technical field of nondestructive testing. Background technique [0002] Non-destructive testing is a detection technology that detects whether there are defects or material inhomogeneities in the structure of the measured object without damaging the function of the measured object. With the development of science and technology, non-destructive testing technology is widely used in the quality control of products, in-service testing of equipment fatigue cracks, and structural integrity assessment. Among them, magnetic flux leakage testing and eddy current testing are two commonly used electromagnetic nondestructive testing methods, which have the advantages of high reliability and no pollution, and play an important role in the detection of defects in key parts of equipment. [0003] The current detection...
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Login to View More IPC IPC(8): G01N27/83G01N27/90G01N27/904
CPCG01N27/83G01N27/9046
Inventor 许鹏朱晨露王平曾泓茗
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS