Metal layer pulsed eddy current thickness measurement method

A pulsed eddy current and metal layer technology, applied in measuring devices, electromagnetic measuring devices, electromagnetic/magnetic thickness measurements, etc., can solve the problem of indistinguishable useful signals, and achieve the effect of improving anti-interference ability and accuracy

Active Publication Date: 2016-07-06
PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE
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Problems solved by technology

It completes the detection based on the phase feature quantity of the signal in the time-frequency domain, which can not only solve the problem that the interference signal caused by lift-off in the time domain is difficult to distinguish from the useful signal generated by the change of the metal layer thickness, but also realize the detection of single-layer or multi-layer metal specimens, and the thickness measurement of the metal layer in non-metallic coating specimens, to improve the accuracy of the test results

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  • Metal layer pulsed eddy current thickness measurement method
  • Metal layer pulsed eddy current thickness measurement method
  • Metal layer pulsed eddy current thickness measurement method

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Embodiment Construction

[0030] Combine below Figure 1 to Figure 6 Further describe the technical solution of the present invention in detail, but the protection scope of the present invention is not limited to the following description.

[0031] Such as figure 1 As shown, a pulsed eddy current detector includes an excitation signal generator, a power amplifier circuit, a detection probe (including an excitation coil and a detection sensor), a signal conditioning circuit, a data acquisition card and a computer. Among them, the excitation signal generator generates an electrical signal with a pulse waveform, which is amplified by the power amplifier circuit, and then loaded into the excitation coil. When the detection probe is close to the measured object of conductive material, an electromagnetic field is generated between the detected object and the measured object. In order to realize the coupling effect, the detection sensor is used to convert the induced magnetic field into an electrical signal,...

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Abstract

The invention discloses a metal layer pulsed eddy current thickness measurement method. The phase jump point of a signal in a time-frequency domain acts as thickness measurement characteristic quantity, a pulsed eddy current detection experiment is performed on multiple standard test pieces of which the thickness is known, and a relation curve between the metal layer thickness and the phase jump point is established and acts as a thickness calibration curve to assist completion of thickness measurement of workpieces to be measured in actual detection. According to the method, extraction of the thickness measurement characteristic quantity is extended to the time-frequency domain from a time domain, and resolution of the signal for parameters to be measured is fully utilized so as to be particularly suitable for thickness measurement of a nonmetal coating layer or a multilayer metal structure. Besides, thickness measurement is realized by utilizing the phase so that probe lift-off interference and metal layer thickness change can be effectively distinguished, anti-interference capacity of detection can be enhanced and accuracy of the measurement result can be guaranteed in comparison with the existing device method of directly adopting the time-domain characteristic quantity.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing, in particular to a method for measuring the thickness of a metal layer by using pulsed eddy current testing technology. Background technique [0002] In many important industrial applications, it is often necessary to measure the thickness of metal layers as a basis for evaluating the quality, safety and reliability of key components in mechanical structures. Pulsed eddy current testing technology is based on the principle of electromagnetic induction to measure the thickness of metal layers. When the excitation coil loaded with pulse voltage (current) is close to the metal specimen to be tested, a transient electromagnetic field will be induced inside the specimen. When the thickness of the specimen is different, the diffusion time and attenuation degree of the induced electromagnetic field inside the specimen will change. , thus causing the signal change of the detection probe,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B7/06
CPCG01B7/10
Inventor 张玉华孙慧贤王建斌李建增左宪章谢志刚李伟
Owner PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE
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