scholarly journals Pipe Crack Recognition Based on Eddy Current NDT and 2D Impedance Characteristics

2019 ◽  
Vol 9 (4) ◽  
pp. 689
Author(s):  
Lianshuang Dai ◽  
Hao Feng ◽  
Ting Wang ◽  
Wenbo Xuan ◽  
Ziqian Liang ◽  
...  
Keyword(s):  
Eddy Current ◽  
Ultrasonic Testing ◽  
Magnetic Flux Leakage ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Electromagnetic Acoustic Transducers ◽  
Acoustic Transducers ◽  
Non Destructive ◽  
Flux Leakage

Girth weld cracking of long-distance oil and gas pipelines yields substantial harm to pipeline safety and may cause serious accidents. As of today, non-destructive testing has been one of the most common methods for predicting potential faults and ensuring safe operation. Classical pipeline non-destructive testing methods include magnetic flux leakage testing and the use of ultrasonic testing by electromagnetic acoustic transducers. However, they are incapable of identifying the defects in complex surfaces like girth welds. Magnetic flux leakage testing exhibits poor anti-interference abilities and low space resolution. Ultrasonic testing by electromagnetic acoustic transducers suffer from low conversion efficiency and poor signal quality. In order to overcome the disadvantages of conventional pipeline non-destructive testing methods, we propose an embedded eddy current testing system by leveraging image processing and neural networks. Hough transform and the contour extraction technique are employed to extract the characteristic features from the two-dimensional (2D) eddy current impedance image. Experiment results show that the system can effectively identify the girth weld defects, featuring an accuracy of up to 92%. The low power consumption and compactness of the proposed system makes it a great candidate for pipeline inner inspection.

Comparison of Non-Destructive Testing Techniques

2021 ◽  
Vol 410 ◽  
pp. 862-866
Author(s):  
Oleg B. Bavykin ◽  
Rodion N. Loginov
Keyword(s):  
Welded Joints ◽  
Ultrasonic Testing ◽  
Ultrasonic Method ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Advantages And Disadvantages ◽  
Comparison Results ◽  
Testing Techniques ◽  
Non Destructive

The article discusses the types of dangerous defects in welded joints. The main methods of non-destructive testing are described, their advantages and disadvantages are briefly reflected. The comparison of the automated ultrasonic testing methods with radiographic ones is given on the example of testing the welded joints of ASME DN350 Py250 pipe fittings with a thickness of the welded edges of 53.9 ÷ 61.3 mm. The comparison results of the methods by the criterion of the accuracy of determining the coordinates of defects are presented, which show the expediency of replacing the automated ultrasonic method with the radiographic one, provided that the thickness of the welded edges is shallow.

scholarly journals Magnetic Flux Leakage Course of Inner Defects and Its Detectable Depth

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jianbo Wu ◽  
Wenqiang Wu ◽  
Erlong Li ◽  
Yihua Kang
Keyword(s):  
Magnetic Flux ◽  
Steel Structure ◽  
High Sensitivity ◽  
Magnetic Flux Leakage ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Near Surface ◽  
Testing Method ◽  
Non Destructive ◽  
Flux Leakage

AbstractAs a promising non-destructive testing (NDT) method, magnetic flux leakage (MFL) testing has been widely used for steel structure inspection. However, MFL testing still faces a great challenge to detect inner defects. Existing MFL course researches mainly focus on surface-breaking defects while that of inner defects is overlooked. In the paper, MFL course of inner defects is investigated by building magnetic circuit models, performing numerical simulations, and conducting MFL experiments. It is found that the near-surface wall has an enhancing effect on the MFL course due to higher permeability of steel than that of air. Further, a high-sensitivity MFL testing method consisting of Helmholtz coil magnetization and induction coil with a high permeability core is proposed to increase the detectable depth of inner defects. Experimental results show that inner defects with buried depth up to 80.0 mm can be detected, suggesting that the proposed MFL method has the potential to detect deeply-buried defects and has a promising future in the field of NDT.

Magnetic Flux Leakage Method of Railway Rails Defects diagnostics and its Place Among Mobile Means of Non-destructive Testing

2018 ◽  
pp. 105-119
Author(s):  
Nichoha, Vitalij ◽  
Shkliarskyi, Volodymyr ◽  
Storozh, Volodymyr ◽  
Matiieshyn, Yurij ◽  
Vashchyshyn, Liubomyr
Keyword(s):  
Magnetic Flux ◽  
Magnetic Flux Leakage ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive ◽  
Flux Leakage

Reduced False Calls in Eddy Current Images Using Signal Processing

2021 ◽  
Author(s):  
S. B. Mahalakshmi ◽  
Ganesh Seshadri ◽  
Aparna Sheila-Vadde ◽  
Manoj Kumar KM
Keyword(s):  
Eddy Current ◽  
Flaw Detection ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Noise Measurements ◽  
Component Manufacturing ◽  
Lift Off ◽  
The Time Domain ◽  
Non Destructive

Abstract Non-destructive testing methods are used largely in component manufacturing industries like Aerospace, Renewables and Power to evaluate the properties of a material or the quality of a component by inspecting for cracks and discontinuities without causing damage to the part. Among the many non-destructive testing methods, Eddy current imaging enables efficient flaw detection for surface and sub-surface cracks. However, in typical eddy current inspection, there can be significant number of false calls arising from variation in lift-off and surface anomalies. Discriminating defect signals from false calls can be very challenging. This paper describes a method to reduce false calls by using a wavelet based denoising algorithm and combining it with statistical-based features extracted inside a sliding window in the time domain to efficiently identify the cracks. The results are verified on specimens with cracks of different sizes that are oriented randomly along with locations available for baseline noise measurements.

scholarly journals Non-Destructive Testing of Steel Corrosion Fluctuation Parameters Based on Spontaneous Magnetic Flux Leakage and Its Relationship with Steel Bar Diameter

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4116 ◽  
Author(s):  
Qingyuan Zhao ◽  
Jianting Zhou ◽  
Qianwen Xia ◽  
Senhua Zhang ◽  
Hong Zhang
Keyword(s):  
Magnetic Flux ◽  
Steel Corrosion ◽  
Magnetic Flux Leakage ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Detection Technology ◽  
Steel Bar ◽  
Steel Bars ◽  
Non Destructive ◽  
Flux Leakage

In an actual structure, the arrangement of steel bars is complicated, there are many factors affecting the corrosion of steel bars, and these factors affect each other. However, accurately reflecting the corrosion of steel bars in actual engineering through theoretical calculations is difficult. Besides, it is impossible to detect and evaluate steel bars rust completely and accurately. This article is based on spontaneous magnetic leakage detection technology and adopts the method of stage corrosion and scanning along the reinforcing bar. Based on spontaneous magnetic flux leakage detection technology, the linear change rate of the tangential component curve of the magnetic flux leakage signal generated after the corrosion of a steel bar is studied, and a comparison is made between the steel bar coated concrete samples with different steel bar diameters. In this paper, the “origin of magnetic flux leakage signal” is defined as a reference point, which is convenient for effectively comparing the magnetic signal curves under all operating conditions. Besides, the “rust-magnetic fluctuation parameter” is proposed to accurately reflect the sudden change of leakage magnetic field caused by disconnection due to the corrosion of a steel bar. A new data processing method is provided for the non-destructive testing of steel corrosion using the spontaneous magnetic flux leakage effect, which can effectively reduce the influence of steel bar diameter on magnetic flux leakage signal and improve the precision of non-destructive testing technology of steel bar corrosion using the metal magnetic memory effect.

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