Journal of Nondestructive Evaluation

, Volume 29, Issue 4, pp 248–252 | Cite as

The Pulsed Eddy Current Differential Probe to Detect a Thickness Variation in an Insulated Stainless Steel

  • C. S. Angani
  • D. G. Park
  • C. G. Kim
  • P. Leela
  • P. Kollu
  • Y. M. Cheong


Non-destructive testing (NDT) plays an important role in the safety and integrity of the large industrial structures such as pipelines in nuclear power plants (NPPs). The pulsed eddy current (PEC) is an electromagnetic NDT approach which is principally developed for the detection of surface and sub surface flaws. In this study a differential probe for the PEC system has been fabricated to detect the wall thinning in insulated steel pipelines. The differential probe contains an excitation coil with two hall-sensors. A stainless steel test sample was prepared with a thickness that varied from 1 mm to 5 mm and was laminated by plastic insulation with uniform thickness to represent the insulated pipelines in the NPPs. Excitation coil in the probe is driven by a rectangular current pulse, the resultant PEC response which is the difference of the two hall sensors is detected. The discriminating features of the detected pulse, peak value and the time to zero were used to describe the wall thinning in the tested sample. A signal processing technique such as power spectrum density (PSD) is devised to infer the PEC response. The results shows that the differential PEC probe has the potential to detect the wall thinning in an insulated pipeline of the nuclear power plants (NPPs).


Differential probe Insulation Time to zero PSD 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Basravi, M.F.: Nondestructive technologies for local industries. In: Proc. of 2nd Middle East Nondestructive Testing Conference (MENDT 2003), vol. 9, No. 4 (2004) Google Scholar
  2. 2.
    Hwang, K.M., Jin, T.E., Lee, S.H., Jeon, S.C.: Wall thinning trend analysis for secondary side piping of Korean NPPs. In: Transactions of 17th Int. Conf. on Structural Mechanics in Reactor Technology (SMiRT 17), August 2003, Czech Republic (2003) Google Scholar
  3. 3.
    Robers, M.A., Scottini, R.S.: Pulsed eddy current in corrosion detection. In: Proc. of 8th ECNDT Conf,, vol. 7, No. 10, June 2002, Barcelona (2002) Google Scholar
  4. 4.
    Yin, W., Peyton, A.J.: Thickness measurement of non magnetic plates using multi frequency eddy current sensors. NDT&E Int. 40, 43–48 (2007) CrossRefGoogle Scholar
  5. 5.
    Moulder, J.C., Uzal, E., Rose, J.H.: Thickness and conductivity of metallic layers from eddy current measurements. Rev. Sci. Instrum. 63, 3455–3465 (1992) CrossRefGoogle Scholar
  6. 6.
    Seturaman, A., Rose, J.H.: Rapid inversion of eddy current data for conductivity and thickness of metal coatings. J. Nondestruct. Eval. 14, 39–46 (1995) CrossRefGoogle Scholar
  7. 7.
    Xiaojun, W., Keqin, D., Hongzhu, W., Zao, N.: Analysis of pulsed magnetic flux leakage signal based on wavelet denoising. In: Proc. of Int. Workshop on Information Security and Application (IWISA 2009), 21 November 2009, China (2009) Google Scholar
  8. 8.
    Yoseph, B.C.: Emerging NDE technologies and challenges at the beginning of the 3rd millennium—part I. Mater. Eval. 58, 17–30 (2000) Google Scholar
  9. 9.
    Waidelich, D.L.: Measurement of coating thickness by use of pulsed eddy currents. Nondestr. Test. 14, 14–16 (1956) Google Scholar
  10. 10.
    Ward, W.W., Moulder, J.C.: Low frequency pulsed eddy currents for deep penetration. Rev. Progress. QNDE 17(A), 291–298 (1998) Google Scholar
  11. 11.
    Nair, N., Melapudi, V., Hector, J., Liu, X., Deng, Y., Zang, Z., Udpa, L., Thomas, J.M., Udpa, S.: A GMR based eddy current system for NDE of aircraft structures. IEEE Trans. Magn. 42, 3312–3314 (2006) CrossRefGoogle Scholar
  12. 12.
    Griberg, R., Udpa, L., Savin, A., Steigmann, R., Palihovic, V., Udpa, S.S.: 2D eddy current sensor array. NDT&E Int. 39, 264 (2006) CrossRefGoogle Scholar
  13. 13.
    Sophian, A., Tian, G.Y., Taylor, D., Rudlin, J.: A feature extraction technique based on the principal component analysis for pulsed eddy current NDT. NDT&E Int. 36, 37–41 (2003) CrossRefGoogle Scholar
  14. 14.
    Zhang, G., Zhao, L.: Research on thickness of metallic layers from pulsed eddy current nondestructive measurements. Transducer Microsyst. Technol. 25(4), 35–37 (2006) Google Scholar
  15. 15.
    Renken, C.J.: The use of personal computer to extract information from Pulsed eddy currents. Mater. Eval. 59(3), 356–360 (2001) Google Scholar
  16. 16.
    Blitz, J.: Electrical and Magnetic Methods of Nondestructive Testing. Chapman & Hall, London (1997) Google Scholar
  17. 17.
    Smith, R.A., Hugo, G.R.: Transient Eddy-current NDE for aging aircraft capabilities and limitations. Insight 43(1), 14–25 (2001) Google Scholar
  18. 18.
    Tian, G.Y., Sophian, A.: Reduction of lift off effects for pulsed eddy current NDT. NDT&E Int. 38(4), 319–324 (2005) CrossRefGoogle Scholar
  19. 19.
    Lepine, B.A., Wallace, B.P., Forsyth, D.S., Wyglinski, A.: Pulsed eddy current method developments for hidden corrosion detection in aircraft structures. In: Proc. of Pan-American Conference for NDT, vol. 3, No. 10, October 1998, Toronto (1998) Google Scholar
  20. 20.
    Shin, Y.K., Choi, D.M.: Signal Characteristics of a differential pulsed eddy current sensor in the evaluation of the plate thickness. NDT&E Int. 42, 215–221 (2009) CrossRefGoogle Scholar
  21. 21.
    Shu, Li, Songling, Huang, Wei, Zhao: Development of differential probes in pulsed eddy current testing for noise suppression. Sens. Actuators A 135, 675–679 (2007) CrossRefGoogle Scholar
  22. 22.
    Bowler, J., Johnson, M.: Pulsed eddy current response to a conducting half space. IEEE Trans. Magn. 33, 2258–2264 (1997) CrossRefGoogle Scholar
  23. 23.
    Krause, T.W., Mandache, C., Lefebvre, J.H.V.: Diffusion of pulsed eddy currents in thin conducting plates. Rev. Quant. Nondestruct. Eval. 27, 368–375 (2008) Google Scholar
  24. 24.
    Youhua, W., Junhua, W., Jiangui, L., Haohua, L.: Analysis of induction heating eddy current distribution based on 3D FEM. In: IEEE Region 8 Int. Conf. on Computational Technologies Electrical and Electronics Engineering, SIBRICON 2008, pp. 238–241 (2008) CrossRefGoogle Scholar
  25. 25.
    Park, D.G., Angani, C.S., Kim, G.D., Kim, C.G.: Evaluation of pulsed eddy current response and detection of the thickness variation in the stainless steel. IEEE Trans. Magn. 45, 3893–3896 (2009) CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • C. S. Angani
    • 1
    • 2
  • D. G. Park
    • 2
  • C. G. Kim
    • 1
  • P. Leela
    • 1
  • P. Kollu
    • 1
  • Y. M. Cheong
    • 2
  1. 1.Department of Material Science and EngineeringChungnam National UniversityDaejeonSouth Korea
  2. 2.Nuclear Materials Research DivisionKorea Atomic Energy Research InstituteDaejeonSouth Korea

Personalised recommendations