A Method Study of Recognizing the Defect Type for the Continuous Casting Slab by Pulsed Eddy Current

Defect of continue casting slab is closely related with technology and working conditions, one productive condition usually leads to the same type of defect. So it has a great practical significance to evaluate the operative process by effective recognition of defect types. In this paper, a damped oscillating signal is acquired by differential method. The defect type of continues casting slab is preliminary qualitative detected via three eigenvalue, the wave peak value(called WPV below), the lagging time of peak(called LTP below) and the peak value difference between the rising and failing edge(called PVD below) which extracting from the differential signal.

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Real-time pre-processing of the pulsed eddy current signal from continuous casting slabs

Insight - Non-Destructive Testing and Condition Monitoring ◽

10.1784/insi.2012.55.3.136 ◽

2013 ◽

Vol 55 (3) ◽

pp. 136-141 ◽

Cited By ~ 5

Author(s):

Xuanbing Qiu ◽

Chao Wei ◽

Xiaochao Cui ◽

Jilin Wei

Keyword(s):

Continuous Casting ◽

Real Time ◽

Eddy Current ◽

Current Signal ◽

Pulsed Eddy Current

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DEVELOPMENT OF SHIELDED REFLECTION TYPE PULSED EDDY CURRENT TESTING PROBES FOR THICKNESS EVALUATION

Modern Physics Letters B ◽

10.1142/s0217984908015619 ◽

2008 ◽

Vol 22 (11) ◽

pp. 923-928

Author(s):

YOUNG-KIL SHIN ◽

DONG-MYUNG CHOI ◽

KWAN-SEOB JANG

Keyword(s):

Eddy Current ◽

Pulse Width ◽

Thickness Variation ◽

Signal Pulse ◽

Test Plate ◽

Zero Crossing ◽

Time To Peak ◽

Pulsed Eddy Current ◽

Crossing Time ◽

Peak Value

Reflection and send-receive type probe shielded by ferrite is designed to evaluate the thickness of test plate by a pulsed eddy current (PEC) method and effects of pulse width to PEC signal are investigated when a 10.5 mm thick, nonmagnetic plate is inspected. Results show that the best sensitivity to thickness variation can be achieved by the peak value of a PEC signal. Pulse width variation study suggests that the shorter pulse width is desired if the peak value or the zero crossing time is used to evaluate the thickness, while the longer pulse width is needed if the time to peak value is used to evaluate it.

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An Improved Feature Parameter Extraction Algorithm of Composite Detection Method Based on the Fusion Theory

Journal of Sensors ◽

10.1155/2021/8898991 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Zhou Ying ◽

Jin Heli ◽

Liu Banteng ◽

Chen Yourong

Keyword(s):

Eddy Current ◽

Dispersion Model ◽

Parameter Extraction ◽

Quantitative Detection ◽

Differential Signal ◽

Feature Parameters ◽

Pulsed Eddy Current ◽

Extraction Algorithm ◽

Feature Parameter ◽

Subsurface Defects

An improved feature parameter extraction algorithm is proposed in this study to solve the problem of quantitative detection of subsurface defects. Firstly, the common feature parameters from the differential signal of pulsed eddy current and ultrasonic are extracted in time domain and frequency domain. Then, the dispersion model and ReliefF model are established to determine the weights of each parameter. Finally, the weights from the two different algorithms are fused by the D-S evidence theory to determine feature parameters. Compared with the PCA feature parameter algorithm from the pulsed eddy current or ultrasonic, the experiment results show the feature parameters extracted by the algorithm proposed in this paper are more effective in quantitative detection of subsurface defects. It will lead to high accuracy in the subsurface defections.

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Defect Classification Using Postpeak Value for Pulsed Eddy-Current Technique

Sensors ◽

10.3390/s20123390 ◽

2020 ◽

Vol 20 (12) ◽

pp. 3390 ◽

Cited By ~ 2

Author(s):

Jiuhao Ge ◽

Chenkai Yang ◽

Ping Wang ◽

Yongsheng Shi

Keyword(s):

Defect Detection ◽

Eddy Current ◽

Surface Defect ◽

Detection Experiment ◽

Pulsed Eddy Current ◽

Current Technique ◽

Calculation Process ◽

Surface Defect Detection ◽

Better Than ◽

Peak Value

In this paper, a feature termed as the postpeak value is proposed for the pulsed eddy current technique (PECT). Moreover, a method using the postpeak value is proposed to classify surface and reverse defects. A PECT system is built for verification purposes. Experiment results prove that the postpeak feature value has better performance than that of the traditional peak value in the case of reverse defect detection. In contrast, the peak value is better than the postpeak value in the case of surface defect detection. Experiment results also validate that the proposed classification algorithm has advantages: classification can be achieved in real time, the calculation process and results are easy to understand, and supervised training is unnecessary.

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Analysis of field uniformity and quantitative evaluation of subsurface pitting corrosion in conductors via GPEC

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209303 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 19-29

Author(s):

Shuting Ren ◽

Yong Li ◽

Bei Yan ◽

Jinhua Hu ◽

Ilham Mukriz Zainal Abidin ◽

...

Keyword(s):

Quantitative Evaluation ◽

Eddy Current ◽

Pitting Corrosion ◽

Gradient Field ◽

Uniform Field ◽

Eddy Current Method ◽

Optimal Position ◽

Pulsed Eddy Current ◽

Field Uniformity ◽

Processing Algorithms

Structures of nonmagnetic materials are broadly used in engineering fields such as aerospace, energy, etc. Due to corrosive and hostile environments, they are vulnerable to the Subsurface Pitting Corrosion (SPC) leading to structural failure. Therefore, it is imperative to conduct periodical inspection and comprehensive evaluation of SPC using reliable nondestructive evaluation techniques. Extended from the conventional Pulsed eddy current method (PEC), Gradient-field Pulsed Eddy Current technique (GPEC) has been proposed and found to be advantageous over PEC in terms of enhanced inspection sensitivity and accuracy in evaluation and imaging of subsurface defects in nonmagnetic conductors. In this paper two GPEC probes for uniform field excitation are intensively analyzed and compared. Their capabilities in SPC evaluation and imaging are explored through simulations and experiments. The optimal position for deployment of the magnetic field sensor is determined by scrutinizing the field uniformity and inspection sensitivity to SPC based on finite element simulations. After the optimal probe structure is chosen, quantitative evaluation and imaging of SPC are investigated. Signal/image processing algorithms for SPC evaluation are proposed. Through simulations and experiments, it has been found that the T-shaped probe together with the proposed processing algorithms is advantageous and preferable for profile recognition and depth evaluation of SPC.

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