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Pulsed eddy current detection method and detection device for conductivity of ferromagnetic metal material

A technology of pulsed eddy current and ferromagnetic metals, which is applied in the direction of measuring devices, material analysis and material analysis through electromagnetic means, can solve the problems of large error and poor repeatability of test results, etc., to weaken the influence, improve the process level, and realize the solution Coupling effect

Active Publication Date: 2019-04-05
BEIHANG UNIV
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Problems solved by technology

In addition, ferromagnetic metal materials are good conductors, which require a large current excitation to generate a large enough voltage signal. Due to the thermal effect of the excitation current and the measurement error of the weak voltage signal, the four-probe method will cause errors in the detection of the conductivity of ferromagnetic metal materials. Larger, poor repeatability of test results

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  • Pulsed eddy current detection method and detection device for conductivity of ferromagnetic metal material
  • Pulsed eddy current detection method and detection device for conductivity of ferromagnetic metal material
  • Pulsed eddy current detection method and detection device for conductivity of ferromagnetic metal material

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Embodiment 1

[0080] The following is an example of using the method of the present invention to detect the conductivity of a ferromagnetic component.

[0081] The ferromagnetic components to be inspected are three cylindrical steel test blocks with a diameter of 100mm and a thickness of 6mm. The materials are 20# steel, 45# steel and Q235 steel respectively.

[0082] Place the coil probes above the centers of the three tested steel test blocks in turn, keep the lift-off distance of the coil probes at 5 mm, and keep the pulse excitation current amplitude I 0 Take 0.2A as the step, gradually increase from 0.2A to 3.0A, first obtain the pulsed eddy current detection signal according to the SAP step in the present invention, and then use the detection signal to establish the least squares problem according to the PIP step to obtain different amplitude pulse current excitation The inversion results of the conductivity and relative permeability of the tested ferromagnetic component are drawn, as...

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Abstract

The invention discloses a pulsed eddy current detection method and a detection device for conductivity of a ferromagnetic metal material, and belongs to the technical field of electromagnetic nondestructive testing. The method comprises the following steps of: using an inductive voltage measurement curve to establish the least squares problem between a measured value of an induced voltage time domain signal and a theoretical calculated value to invert the conductivity and magnetic permeability of a ferromagnetic member to be tested, based on a time-domain analytical solution of an induced voltage of a pulsed eddy current detection model of a ferromagnetic plate; obtaining a change curve of conductivity inversion results under different amplitude pulse current excitations by gradually increasing the amplitude of a pulse excitation current; and finding an intersection point of the change curve of the conductivity inversion results and an ordinate axis by a curve fitting method, that is,the conductivity of the ferromagnetic member to be tested. The method and device provided by the invention can provide non-contact and nondestructive detection for the conductivity of the ferromagnetic metal material in the industry, weaken the influence of the nonlinear change of the magnetic permeability on the conductivity detection result, and improve the accuracy and reliability.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic nondestructive testing, and in particular relates to a pulsed eddy current testing method and a testing device for the conductivity of ferromagnetic metal materials. Background technique [0002] Electrical conductivity is an important parameter to characterize the electrical conductivity of metal materials, and it is closely related to the material, microstructure, and heat treatment state of the material. By detecting the conductivity of ferromagnetic metal materials, it is possible to sort and identify raw materials, judge the heat treatment status such as annealing and quenching, evaluate the hardness and mechanical properties of ferromagnetic components, and detect the residual stress and metallographic changes in ferromagnetic components, etc. . Therefore, the nondestructive testing of the conductivity of ferromagnetic metal materials has important application value. [0003] For n...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/02G01R27/02
CPCG01N27/025G01R27/02
Inventor 陈兴乐王兆晖厉静雯
Owner BEIHANG UNIV
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