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.

Design of orthogonal eddy-current probe for weld crack detection of carbon-steel plate

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1347-1355
Author(s):  
Tao Chen ◽  
Xiaoqi Xiao ◽  
Lihong Zhang ◽  
Cheng Lv ◽  
Zhiyang Deng ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Eddy Current ◽  
Crack Detection ◽  
Steel Plate ◽  
Signal To Noise Ratio ◽  
Detection Sensitivity ◽  
Scanning Angle ◽  
Length Width ◽  
Lift Off ◽  
Detection Effect

Due to uneven surface and lift-off effect, it is difficult to detect weld crack by eddy-current testing. A new orthogonal eddy-current probe for weld crack detection of carbon-steel plate was designed in this paper. Based on COMSOL Multiphysics, the influence of scanning angle on detection sensitivity of the probe was compared firstly. Then, the effects of coil width, coil side length, detection coil height, and lift-off distance on detection sensitivity of the probe were studied, respectively. Finally, the test piece of carbon-steel plate weld with crack, and the physical probe used to verify the crack detection effect were made. The experimental results show that the weld crack of carbon-steel plate with length × width × depth of 20.0 mm × 0.3 mm × 1 mm can be effectively identified, and the lift-off noise can be effectively suppressed by the method presented in this paper. At the same time, the signal-to-noise ratio of the probe keeps constant in the lift-off distance range of 0.3 mm–3.0 mm.

scholarly journals Evaluation of Coating Thickness Using Lift-Off Insensitivity of Eddy Current Sensor

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 419
Author(s):  
Xiaobai Meng ◽  
Mingyang Lu ◽  
Wuliang Yin ◽  
Abdeldjalil Bennecer ◽  
Katherine J. Kirk
Keyword(s):  
Eddy Current ◽  
Coating Thickness ◽  
Thickness Measurement ◽  
Eddy Current Testing ◽  
Thickness Variation ◽  
Testing Technique ◽  
Current Testing ◽  
Thin Skin ◽  
Embedded Algorithms ◽  
Lift Off

Defect detection in ferromagnetic substrates is often hampered by nonmagnetic coating thickness variation when using conventional eddy current testing technique. The lift-off distance between the sample and the sensor is one of the main obstacles for the thickness measurement of nonmagnetic coatings on ferromagnetic substrates when using the eddy current testing technique. Based on the eddy current thin-skin effect and the lift-off insensitive inductance (LII), a simplified iterative algorithm is proposed for reducing the lift-off variation effect using a multifrequency sensor. Compared to the previous techniques on compensating the lift-off error (e.g., the lift-off point of intersection) while retrieving the thickness, the simplified inductance algorithms avoid the computation burden of integration, which are used as embedded algorithms for the online retrieval of lift-offs via each frequency channel. The LII is determined by the dimension and geometry of the sensor, thus eliminating the need for empirical calibration. The method is validated by means of experimental measurements of the inductance of coatings with different materials and thicknesses on ferrous substrates (dual-phase alloy). The error of the calculated coating thickness has been controlled to within 3% for an extended lift-off range of up to 10 mm.

Differential coupling double-layer coil for eddy current testing with high lift-off

2021 ◽  
pp. 1-1
Author(s):  
Kefan Chen ◽  
Bin Gao ◽  
G.Y. Tian ◽  
Yupei Yang ◽  
Changrong Yang ◽  
...  
Keyword(s):  
Double Layer ◽  
Eddy Current ◽  
Eddy Current Testing ◽  
High Lift ◽  
Current Testing ◽  
Lift Off ◽  
Differential Coupling

Inversion of lift-off distance and thickness for non-magnetic metal using eddy current testing

2020 ◽  
pp. 1-1
Author(s):  
Xiaobai Meng ◽  
Mingyang Lu ◽  
Wuliang Yin ◽  
Abdeldjalil Bennecer ◽  
Katherine J Kirk
Keyword(s):  
Eddy Current ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Magnetic Metal ◽  
Lift Off

scholarly journals The Effects of Lift-Off from Wall Thinning Signal in Pulsed Eddy Current Testing

2012 ◽  
Vol 17 (4) ◽  
pp. 298-301 ◽  
Author(s):  
Duck-Gun Park ◽  
C.S. Angani ◽  
M.B. Kishore ◽  
C.G. Kim ◽  
D.H. Lee
Keyword(s):  
Eddy Current ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Pulsed Eddy Current ◽  
Wall Thinning ◽  
Lift Off

scholarly journals Evaluation of Coating Thickness Using Lift-Off Insensitivity of Eddy Current Sensor

2021 ◽  
Author(s):  
Xiaobai Meng ◽  
Mingyang Lu ◽  
Wuliang Yin ◽  
Abdeldjalil Bennecer ◽  
Katherine Kirk
Keyword(s):  
Eddy Current ◽  
Coating Thickness ◽  
Thickness Measurement ◽  
Eddy Current Testing ◽  
Thickness Variation ◽  
Testing Technique ◽  
Current Testing ◽  
Thin Skin ◽  
Embedded Algorithms ◽  
Lift Off

Defect detection in ferromagnetic substrates is often hampered by non-magnetic coating thickness variation when using conventional eddy current testing technique. The lift-off distance between the sample and the sensor is one of the main obstacles for the thickness measurement of non-magnetic coatings on ferromagnetic substrates when using the eddy current testing technique. Based on the eddy current thin-skin effect and the lift-off insensitive inductance (LII), a simplified iterative algorithm is proposed for reducing the lift-off variation effect using a multi-frequency sensor. Compared to the previous techniques on compensating the lift-off error (e.g., the lift-off point of intersection) while retrieving the thickness, the simplified inductance algorithms avoid the computation burden of integration, which are used as embedded algorithms for the online retrieval of lift-offs via each frequency channel. The LII is determined by the dimension and geometry of the sensor, thus eliminating the need for empirical calibration. The method is validated by means of experimental measurements of the inductance of coatings with different materials and thicknesses on ferrous substrates (dual-phase alloy). The error of the calculated coating thickness has been controlled to within 3 % for an extended lift-off range of up to 10 mm.

scholarly journals Study on the Optimization of Eddy Current Testing Coil and the Defect Detection Sensitivity

2015 ◽  
Vol 130 ◽  
pp. 1649-1657 ◽  
Author(s):  
H.T. Zhou ◽  
K. Hou ◽  
H.L. Pan ◽  
J.J. Chen ◽  
Q.M. Wang
Keyword(s):  
Defect Detection ◽  
Eddy Current ◽  
Eddy Current Testing ◽  
Detection Sensitivity ◽  
Current Testing

scholarly journals Lift-off Invariant Inductance of Steels in Multi-Frequency Eddy-Current Testing

2021 ◽  
Author(s):  
Mingyang Lu ◽  
Xiaobai Meng ◽  
Ruochen Huang ◽  
Liming Chen ◽  
Anthony Peyton ◽  
...  
Keyword(s):  
Eddy Current ◽  
High Accuracy ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Pulsed Eddy Current ◽  
Working Frequency ◽  
Lift Off ◽  
Ferromagnetic Steels ◽  
Point Of Intersection ◽  
Steel Properties

Eddy current testing can be used to interrogate steels but it is hampered by the lift-off distance of the sensor. Previously, the lift-off point of intersection (LOI) feature has been found for the pulsed eddy current (PEC) testing. In this paper, a lift-off invariant inductance (LII) feature is proposed for the multi-frequency eddy current (MEC) testing, which merely targets the ferromagnetic steels. That is, at a certain working frequency, the measured inductance signal is found nearly immune to the lift-off distance of the sensor. Such working frequency and inductance are termed as the lift-off invariant frequency (LIF) and LII. Through simulations and experimental measurements of different steels under the multi-frequency manner, the LII has been verified to be merely related to the sensor parameters and independent of different steels. By referring to the LIF of the test piece and using an iterative inverse solver, one of the steel properties (either the electrical conductivity or magnetic permeability) can be reconstructed with a high accuracy.

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