scholarly journals Natural Rail Surface Defect Inspection and Analysis Using 16-Channel Eddy Current System

2021 ◽  
Vol 11 (17) ◽  
pp. 8107
Author(s):  
Se-Gon Kwon ◽  
Taek-Gyu Lee ◽  
Sang-Jun Park ◽  
Jeong-Won Park ◽  
Jong-Min Seo
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Safety Management ◽  
Current System ◽  
Detection Sensitivity ◽  
Defect Inspection ◽  
Artificial Defect ◽  
Eddy Current Inspection ◽  
Train Operation ◽  
Inspection Systems

Trains are used as the fastest mode of transportation for both people and cargo. The train moves along a special path called 'rail,' where fatigue can be accumulated due to wheel-rail contact load as a result of continuous train operation. Consistent and regularly scheduled safety management is required since corrosion rate of the rails located on outside environment is very high. Researchers have actively investigated and developed rail defect inspection systems employing non-destructive techniques to address these problems. In particular, the eddy current inspection technique does not involve contact with the surface of the test specimen and offers the advantage of excellent rail defect detection sensitivity. Therefore, a 16 Ch array eddy current inspection device was developed to inspect the surface defects of the rail. An equation was derived to predict the correlation between the depth and phase of an artificial defect using the eddy current inspection device, and the derived equation was applied to the natural defect specimen.

Limitations of eddy current inspection in railway rail evaluation

2016 ◽  
Vol 232 (1) ◽  
pp. 121-129 ◽  
Author(s):  
Juho Rajamäki ◽  
Minnamari Vippola ◽  
Antti Nurmikolu ◽  
Tuomo Viitala
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Great Sensitivity ◽  
Rolling Contact ◽  
Electromagnetic Properties ◽  
Depth Of Penetration ◽  
Railway Network ◽  
Near Surface ◽  
Eddy Current Inspection ◽  
Deep Inspection

At the moment, one of the most cost-effective ways to inspect a whole railway network for rolling-contact fatigue is to carry out an eddy current inspection. It has a great sensitivity to even the smallest near surface defects, but this can also be a downside as it can lead to indications of deep damage from an array of tiny cracks. This can lead to overestimation of damage severity. Moreover, sizing of cracks in rails is unreliable due to the large number of parameters that affect the eddy current inspection response. The depth of penetration is of major importance in eddy current inspection, since cracks that are over this limit cannot be sized reliably. Deep inspection is desirable, but it is unattainable in practice, since signal-to-noise ratio decreases while penetration increases. Also, deep inspection is more affected by variations in steel’s electromagnetic properties. Furthermore, increasing inspection velocity will lead to decreased inspection depth. Most of the problems with eddy current inspection are related to the surface microstructure of the rail, and thus could be mitigated with a preliminary rail grinding. Therefore, eddy current inspection is best suited for maintenance quality control. However, eddy current inspection carried out with conventional equipment and without support from other methods gives only coarse estimate of the rails condition.

Development of Eddy Current Inspection System for Detection of Surface Defects on Hot Steel Slabs

1987 ◽  
Vol 20 (8) ◽  
pp. 401-405
Author(s):  
T. Sugimoto ◽  
K. Kaya ◽  
H. Okumura ◽  
M. Wakoh ◽  
T. Kawaguchi
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Inspection System ◽  
Eddy Current Inspection ◽  
Steel Slabs

Design of the Eddy Current Sensor of Steel Ball Nondestructive Detection

2012 ◽  
Vol 271-272 ◽  
pp. 842-846 ◽  
Author(s):  
Feng Qin Xie ◽  
Lin Jing Xiao ◽  
Ya Peng Lu ◽  
Hua Yu Zhang
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Current System ◽  
Nondestructive Method ◽  
Current Sensor ◽  
Nondestructive Detection ◽  
The Core ◽  
Ball Surface ◽  
Steel Balls ◽  
Core Part

The ball surface and sub-surface defects can be test by the eddy current nondestructive method. The core part of the eddy current system is the sensor’s design, including the coil and the process of induction signals. At the end, through experiment of detecting a set of defect ball, with a better result. It’s shows that the amplitude of the detection signal is proportional to the depth of the steel balls crack.

Limitations of eddy current inspection for the characterization of near-surface cracks in railheads

2021 ◽  
pp. 095440972110295
Author(s):  
Rayendra Anandika ◽  
Jan Lundberg
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Crack Depth ◽  
Surface Cracks ◽  
Important Conclusion ◽  
Near Surface ◽  
Eddy Current Inspection ◽  
Signal Response ◽  
Crack Profile

Eddy current (EC) testing is the most commonly used method to inspect near-surface cracks in railheads. Monitoring surface defects periodically is important to assess the track quality for serving daily operations. Nevertheless, despite being used in many countries, this method has limitations when characterizing cracks under the rail surface. Theoretically, EC testing is unreliable for the inspection of many cracks situated too close to each other in a concentrated location. This study has aimed to prove these limitations. EC signals from inspected cracks were compared with real crack profile parameters, i.e. depth and area, which were delivered by slicing the inspected cracked spots into 0.65 mm-thick pieces. The results show that the EC signal responses to the parameters of area and depth may lead to misleading measurements of the near-surface crack depth in the railhead. For instance, a shallower crack with a larger area can generate a higher EC signal response than a deeper crack with a smaller area. Another important conclusion is that the EC testing in this experiment could not be used to measure densely located cracks, which are those near-surface cracks which are typically found in a rail track.

scholarly journals Rail Surface Defect Detection and Analysis Using Multi-Channel Eddy Current Method Based Algorithm for Defect Evaluation

2021 ◽  
Vol 40 (3) ◽  
Author(s):  
Jeong Won Park ◽  
Taek Gyu Lee ◽  
In Chul Back ◽  
Sang Jun Park ◽  
Jong Min Seo ◽  
...  
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Current Method ◽  
Fatigue Loading ◽  
Electrical Signal ◽  
Detection Sensitivity ◽  
Eddy Current Method ◽  
Tension And Compression ◽  
Surface Defect Detection ◽  
Evaluation Algorithm

AbstractThe railroad rail support trains and contributes to their operation. Internal and surface defects occur on the rail due to various combinations of causes including fatigue loading and cyclic tension and compression among others from the deterioration of the rail along with the temperature differences of seasonal changes. Surface defects such as head check, shelling, and squats start out in the rail head and become internal defects due to poor maintenance, ultimately resulting in rail failure. In order to prevent rail failure, it is important that defects are identified through nondestructive evaluation (NDE) in advance and to carry out maintenance techniques including grinding. NDE methods include MFL, EMAT, and ECT, and among these, the ECT method is a representative method with excellent detection sensitivity that nondestructively inspects metal surfaces such as rails and pipes using an electromagnetic field. Also, since the defect signal is obtained as an electrical signal, the depth, length, and width of defects can be assessed using a defect evaluation algorithm. This study investigated the field applicability and future practical use of the 16 channel eddy current testing equipment and defect evaluation algorithm developed in this study. Therefore, the field applicability of the equipment and defect evaluation algorithm was investigated through the detection of artificial defects with varying size and depth. Afterwards, future practical use was evaluated by inspection of areas of rail that are in use and with naturally occurring surface defects and analysis of their size (length, width), depth, and phenomena.

scholarly journals Research on Detection Mechanism of Weld Defects of Carbon Steel Plate Based on Orthogonal Axial Eddy Current Probe

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5515
Author(s):  
Linnan Huang ◽  
Chunhui Liao ◽  
Xiaochun Song ◽  
Tao Chen ◽  
Xu Zhang ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Eddy Current ◽  
Steel Plate ◽  
Difficult Problem ◽  
Eddy Current Testing ◽  
Detection Sensitivity ◽  
Detection Mechanism ◽  
Current Testing ◽  
Weld Defects ◽  
Lift Off

The uneven surface of the weld seam makes eddy current testing more susceptible to the lift-off effect of the probe. Therefore, the defect of carbon steel plate welds has always been a difficult problem in eddy current testing. This study aimed to design a new type of eddy current orthogonal axial probe and establish the finite element simulation model of the probe. The effect of the probe structure, coil turns, and coil size on the detection sensitivity was simulated. Further, a designed orthogonal axial probe was used to conduct a systematic experiment on the weld of carbon steel specimens, and the 0.2 mm width and 1 mm depth of weld defects of carbon steel plates were effectively detected. The experimental results showed that the new orthogonal axial eddy current probe effectively suppressed the unevenness effect of the weld surface on the lift-off effect during the detection process.

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