Method and device for detecting corrosion of component with permeability magnetic material protective layer

A corrosion detection and protective layer technology, applied in the field of non-destructive testing based on pulsed eddy current, can solve the problem of low sensitivity and achieve the effect of increasing penetration depth, improving detection sensitivity and reducing magnetic permeability

Inactive Publication Date: 2009-09-02
HUAZHONG UNIV OF SCI & TECH
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Problems solved by technology

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for detecting corrosion of components with a protective layer of magnetically permeable

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  • Method and device for detecting corrosion of component with permeability magnetic material protective layer
  • Method and device for detecting corrosion of component with permeability magnetic material protective layer
  • Method and device for detecting corrosion of component with permeability magnetic material protective layer

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[0029] The principle diagram of the detection method of the present invention is as follows figure 1 As shown, the measured component 1 is covered with a coating layer 2 with a thickness of H, and the coating layer 2 is wrapped with a magnetically conductive protective layer 3 with a thickness of h. The upper end of the permanent magnet 4 is adsorbed on the left and right ends of the yoke 7, and the polarities of the magnets at both ends are perpendicular to the measured component 1 and opposite. The lower end of the permanent magnet 4 is adsorbed (or lifted a certain distance) on the magnetic protective layer 3. The permanent magnet 4 , The yoke 7 and the magnetic protective layer 3 form a closed magnetic path, magnetize the magnetic protective layer 3 to deep saturation or deep saturation, reduce the permeability of the magnetic protective layer material, and increase the penetration depth of the eddy current. The attenuation of the eddy current on the magnetic conductive prote...

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Abstract

The invention provides a method for detecting the corrosion of a component with a permeability magnetic material protective layer. The method comprises the following steps: the permeability magnetic material protective layer is magnetized to be saturated or deeply saturated, a reference area and a area to be detected are selected on the surface of a detected component, pulsed eddy current sensors are arranged on the protective layers of the two areas, the square-wave exciting is applied to exciting coils of the pulsed eddy current sensors, the attenuation curve of the induced voltage in the detecting coils of pulsed eddy current sensors is measured after the level of square waves is reduced to the low level, and the difference between the attenuation curves of the induced voltage in the two areas is compared, thus the corrosion condition of the area to be detected relative to the reference area can be further distinguished. The invention also provides a device for realizing the method, which comprises a pulsed eddy current sensor, a square-wave signal exciting circuit, a signal processing circuit, an A/D conversion circuit and a computer which are connected in sequence, wherein the pulsed eddy current sensor is provided with a magnetization unit. The invention improves the sensitivity of corrosion detection of the component with the permeability magnetic material protective layer and is suitable for detecting the corrosion of the component on-line without dismounting the protective layer and the cladding layer.

Description

technical field [0001] The invention relates to the field of non-destructive testing, in particular to a non-destructive testing method and device based on pulsed eddy current, and is especially suitable for non-stop testing of components with a protective layer of magnetic-permeable material without dismantling the protective layer and cladding layer. Background technique [0002] Ferromagnetic components with a protective layer of magnetic conductive materials, such as steam pipes and pressure vessels, are widely used in oil and gas, chemical industry, water supply and heating and other industries. The insulating material is coated on the outside of the component, and the outside of the coating is usually protected by a metal The protective layer is used to prevent rain, and the commonly used protective layer materials are aluminum, stainless steel or tinplate. At present, the corrosion detection of ferromagnetic components with cladding layers is usually carried out by re...

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Application Information

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IPC IPC(8): G01N27/90G01N27/904
Inventor 武新军徐志远黄琛丁旭康宜华徐江
Owner HUAZHONG UNIV OF SCI & TECH
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