Pulsed eddy current detection method with variable pulse width excitation

A pulsed eddy current and detection method technology, applied in the direction of measuring devices, material magnetic variables, instruments, etc., can solve the problems of susceptibility to noise, amplitude detection defects, limited information, etc. The effect of the operation

Inactive Publication Date: 2016-08-31
HUAZHONG UNIV OF SCI & TECH
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Problems solved by technology

The above method has the following disadvantages: (1) the defect is detected by the amplitude of a certain point of the detection signal or the differential signal, which is easily affected by noise; (2) the excitation coil of the sensor is loaded with a pulse excitation of a preset frequency, and its pulse width Invariant, limited information obtained from detection signal

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  • Pulsed eddy current detection method with variable pulse width excitation
  • Pulsed eddy current detection method with variable pulse width excitation
  • Pulsed eddy current detection method with variable pulse width excitation

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Embodiment Construction

[0031] In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not constitute a conflict with each other.

[0032] Such as figure 1 As shown, the pulsed eddy current detection method with variable pulse width excitation in the embodiment of the present invention includes the following steps:

[0033] (1) Place the pulsed eddy current sensor on the test piece.

[0034] (2) Set the current excitation pulse width PW cur = t 0 , t 0 The value range of is [1ms, 100ms].

[0035] (3) The detection s...

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Abstract

The invention discloses a pulse eddy current detection method excited by variable pulse width. The method includes the following steps: (1) placing the pulsed eddy current sensor on the tested object; (2) setting the current excitation pulse width PWcur=t0; (3) acquiring the detection signal, and the measurement time interval is [0,t]; ( 4) Calculate the integral INcur of the detection signal on the time interval [t1,t2]; (5) Set the next excitation pulse width PWnext=PWcur+PWadd; (6) Obtain the detection signal, and the measurement time interval is [0,t]; (7) Calculate the integral INnext of the detection signal on the time interval [t1,t2]; (8) Calculate RIcur=(INnext‑INcur) / INcurPWadd, compare RIcur with the preset threshold value RIT, if RIcur

Description

technical field [0001] The invention belongs to the technical field of electromagnetic nondestructive testing, and more specifically relates to a pulsed eddy current testing method with variable pulse width excitation. Background technique [0002] During the use of pressure vessels and pipelines, the wall thickness is often thinned due to corrosion and erosion, which seriously threatens the safety of industrial production. Since the pulsed eddy current testing technology adopts the excitation in the form of pulses, it is not necessary to remove the covering layer outside the pressure vessel and the pipeline during the testing, and it can detect deep-seated defects. It has the advantages of fast speed, good safety, and low cost. One of the preferred techniques for detecting pressure vessel and pipe wall thickness reduction. [0003] In the pulsed eddy current testing technology, the excitation in the form of a pulse is applied to the excitation coil close to the test piece....

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N27/90G01N27/904
Inventor 武新军李建张卿
Owner HUAZHONG UNIV OF SCI & TECH
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