Method and circular tangent vortex probe for detection of deep cracks

A technology of eddy current probes and deep cracks, applied in the direction of material magnetic variables, etc., can solve the problems of unobtainable, small eddy current penetration depth, low resolution, etc., and achieve the effect of avoiding missed detection of cracks, small eddy current penetration depth, and improving sensitivity

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

AI Technical Summary

Problems solved by technology

Although the detection effect of deep cracks can be improved to a certain extent by optimizing the excitation frequency and other measures, there are other problems at the same time. It can, 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, compared with traditional eddy current detection It has 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 crack depth that can be detected is limited, and ideal results cannot be obtained for deep cracks. The eddy current induced in the material by the rectangular excitation coil is directional, and it is easy to miss detection of cracks parallel to the flow direction of the eddy current
[0005] To sum up, the main problems existing in the existing technology are: (1) The eddy current penetration depth generated by conventional eddy current probes is too small to obtain the detection signal of deep cracks; (2) The detection signal of deep defects in materials is small and susceptible to The problem of excitation magnetic field noise interference; (3) The coil size of the conventional deep crack detection probe is too large; (4) The uniform eddy current probe is sensitive to the crack direction

Method used

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  • Method and circular tangent vortex probe for detection of deep cracks
  • Method and circular tangent vortex probe for detection of deep cracks
  • Method and circular tangent vortex probe for detection of deep cracks

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] Such as figure 1 As shown, the circular tangential eddy current probe used to detect deep cracks includes an excitation element, a detection element and a fixing frame 9; the fixing frame 9 includes a scanning frame connecting portion 91 and an element mounting portion 92, and the element mounting portion 92 A component mounting surface 921 is arranged on it; it is characterized in that: the excitation element includes a large excitation coil 1, a large excitation coil winding disk 6, a small excitation coil 2 and a small excitation coil winding post 7; the large excitation coil is wound The disk 6 is fixedly mounted on the component mounting surface 921 of the component mounting part 92; the small excitation coil winding column 7 is fixedly mounted on the top surface of the large excitation coil winding disk 6, and the outer edges of the two are inscribed; the large excitation coil 1 Set on the large excitation coil winding disk 6, the small excitation coil 2 is sleeve...

Embodiment 2

[0073] Such as figure 2 As shown, on the basis of Embodiment 1, a method for detecting deep crack defects using the above-mentioned circular tangential eddy current probe for detecting deep cracks is characterized in that it includes the following steps:

[0074] S1. Probe assembly: operate as follows:

[0075] First, install the actuator. First, the large excitation coil winding reel 6 is fixedly installed on the component mounting surface 921 of the fixed frame 9, and then the small excitation coil winding post 7 is fixedly installed on the top surface of the large excitation coil winding reel 6, so that the outer edges of the two Inner cutting; then the large excitation coil 1 is set on the large excitation coil winding disk 6, and the small excitation coil 2 is placed on the small excitation coil winding column 7, so that the outer edge of the small excitation coil 2 is in contact with the outer edge of the large excitation coil 1 Inscribed edge.

[0076]Next, install ...

Embodiment 3

[0084] In order to verify that the penetration depth of the circular tangential eddy current probe used to detect deep cracks in the present invention 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, 304 Austrian For the test piece of stainless steel, the circular tangential eddy current probe for detecting deep cracks of the present invention is adopted and 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. The obtained traditional circular eddy current probe is tested according to the following parameter configuration and method, and a comparative experiment is carried out with an excitation frequency of 1kHz.

[0085] 1. The detection experiment of the traditional self-generating and self-retracting circular eddy current probe.

[0086] a. On the basis of Examp...

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Abstract

The invention belongs to the technical field of electromagnetic nondestructive testing and relates to a method and a circular tangent vortex probe for detection of deep cracks. The vortex probe comprises an exciting element, a detecting element and a holder (9); the exciting element comprises a big exciting coil (1), a big exciting coil reel (6), a small exciting coil (2) and a small exciting coilwinding post (7); the big exciting coil (1) is tangent to the small exciting coil (2); the detecting element comprises a detecting coil support (11), a detecting coil winding post (8), a magnetic field shield board (5), a detecting coil (3) and a magnetic field shield cylinder (4), the magnetic field shield board (5), the detecting coil (3) and the magnetic field shield cylinder (4) sleeve the detecting coil winding post (8) sequentially, and the detecting coil (3) is arranged in a shield shell formed by the magnetic field shield board (5) and the magnetic field shield cylinder (4). The probehas great detection depth and high efficiency.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic non-destructive testing, and relates to an eddy current probe used for defect detection in nuclear power and other important industrial fields, in particular to a circular tangential eddy current probe and a method for detecting deep cracks. 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-contact, fast detection speed an...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): G01N27/90
CPCG01N27/9006
Inventor武美先张东利
OwnerBEIFANG UNIV OF NATITIES