Interlink-type vortex probe and method for detecting deep cracks of opening fatigue and stress corrosion

A technology of stress corrosion and eddy current probes, applied in measuring devices, instruments, and material analysis through electromagnetic means, can solve the problems of low sensitivity, low resolution, and small eddy current penetration depth of Hall elements, etc., to avoid crack leakage The detection situation, the detection depth is large, and the effect of improving sensitivity

Active Publication Date: 2019-03-01
BEIFANG UNIV OF NATITIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although measures such as optimizing the excitation frequency can improve the detection effect of deep cracks to a certain extent, there are other problems at the same time: for example, the use of low-frequency excitation and far-field eddy current can increase the penetration depth of eddy current and improve the ability of the probe to detect deep defects. , but at the same time it will lead to low probe resolution, low signal-to-noise ratio, low detection speed, and cause problems such as the speed effect of the probe and the difficulty in distinguishing detection signals; using pulsed eddy current to detect defects with multi-frequency signals has advantages compared with traditional eddy current testing. Certain advantages, but the pulsed eddy current signal will be polluted by noise during the process of generation, transmission and reception, the Hall element used is not sensitive, and the resolution is easily affected by offset and noise
[0004] Although the conventional uniform eddy current probe solves the problems of low resolution and low signal-to-noise ratio, it still cannot get rid of the limitation of skin effect. The eddy current induced by the rectangular excitation coil in the material is directional, and it is easy to miss detection of cracks parallel to the flow direction of the eddy current
[0005] In summary, the main problems existing in the prior art are: (1) The eddy current penetration depth generated by the traditional eddy current probe is too small, making it difficult to detect deep cracks; (2) The deep crack detection signal is interfered by the excitation magnetic field noise; (3) The uniform eddy current probe is sensitive to the crack direction

Method used

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  • Interlink-type vortex probe and method for detecting deep cracks of opening fatigue and stress corrosion
  • Interlink-type vortex probe and method for detecting deep cracks of opening fatigue and stress corrosion
  • Interlink-type vortex probe and method for detecting deep cracks of opening fatigue and stress corrosion

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] Such as figure 1 As shown, the serial eddy current probe for detecting opening fatigue and stress corrosion deep cracks includes an excitation element, a detection element and a fixing frame 9; it is characterized in that: the fixing frame 9 includes a scanning frame connecting portion 91 and an element mounting portion 92, The element installation part 92 is provided with an element installation surface 921 ; the excitation element and the detection element are both installed on the element installation surface 921 .

[0059] The excitation element includes a large excitation coil 1, a large excitation coil winding column 6, a small excitation coil 2, and a small excitation coil winding column 7; the large excitation coil winding column 6 and the small excitation coil winding column 7 are vertically fixed Installed on the component mounting surface 921 of the fixing frame 9 ; the large excitation coil 1 is wound on the large excitation coil winding post 6 , and the sma...

Embodiment 2

[0072] Such as figure 2 As shown, on the basis of Embodiment 1, a method for detecting thick-walled deep crack defects using the above-mentioned serial eddy current probe is characterized in that it includes the following steps:

[0073] S1. Probe assembly: operate as follows:

[0074] First, install the actuator. First fix one end of the large excitation coil winding column 6 and the small excitation coil winding column 7 vertically on the component mounting surface 921 of the component mounting part 92 of the fixing frame 9, and then install the large excitation coil 1 and the small excitation coil 2 respectively Wound on the large excitation coil winding post 6 and the small excitation coil winding post 7, keep the top surfaces of the large excitation coil 1 and the small excitation coil 2 and the tops of the large excitation coil winding post 6 and the small excitation coil winding post 7 face flush.

[0075] Next, install the detection element. First, one end of the ...

Embodiment 3

[0083] In order to verify that the penetration depth of the chain-type eddy current probe is better than that of the traditional circular eddy-current probe when detecting thick-walled deep crack defects, on the basis of Examples 1 and 2, a 304 austenitic stainless steel test piece is used to adopt the chain-type eddy current probe of the present invention. The eddy current probe and the traditional self-generating and self-retracting circular eddy current probe obtained when the small excitation coil 2 and the detection coil 3 are not installed, and only the large excitation coil 1 is installed and used for excitation and defect detection, are configured and tested according to the following parameters , with 10kHz excitation frequency, for comparative experiments.

[0084] 1. The detection experiment of the traditional self-generating and self-retracting circular eddy current probe.

[0085] a. On the basis of Examples 1 and 2, only the large excitation coil 1 is used for ex...

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Abstract

The invention belongs to the technical field of electromagnetic non-destructive testing, and relates to an interlink-type vortex probe and a method for detecting deep cracks of opening fatigue and stress corrosion. The probe comprises an excitation component, a detection component and a fixing frame (9). The fixing frame (9) comprises a scanning frame connecting portion (91) and an component mounting portion (92), and the component mounting portion (92) is provided with a component mounting surface (921); the excitation component comprises a large exciting coil (1), a large exciting coil winding column (6), a small exciting coil (2) and a small exciting coil winding column (7); the detection component comprises a detection coil (3), a detection coil winding column (8), a magnetic field shielding plate (4) and a magnetic field shielding cylinder (5); the large exciting coil winding column (6), the small exciting coil winding column (7) and the detection coil winding column (8) are linearly arranged in sequence, and the bottom ends are vertically and fixedly mounted on the component mounting surface (921). The probe has a large detection depth that can be up to 25mm.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic nondestructive testing, and relates to an eddy current probe used for defect detection in nuclear power and other important industrial fields, in particular to a serial eddy current probe and a method for detecting deep cracks in opening fatigue and stress corrosion. Background technique [0002] Eddy current testing is one of the conventional non-destructive testing technologies. It is based on the principle of electromagnetic induction and is an electromagnetic testing method for defect detection and performance testing of materials and components based on changes in the electromagnetic properties of materials. The eddy current testing method uses an excitation coil to generate a vortex-shaped induced alternating current in the test piece, and judges the position and size of the defect through the change of the voltage signal of the coil. This method has the characteristics of non-contac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/90
CPCG01N27/9006Y02E30/30
Inventor 张东利武美先
Owner BEIFANG UNIV OF NATITIES
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