Evaluation of back-side flaws of the bottom plates of an oil-storage tank by the RFECT

In the present study, the remote field eddy current testing (RFECT) was used to detect back-side local corrosion in the bottom plates of an oil storage tank constructed of a ferromagnetic material. A phenomenon similar to a remote field for a tube-type test piece was confirmed in this measurement system with/without the U-type component. The appropriate distance between the excitation coil and the pick-up coil and the excitation frequency were experimentally examined to detect the back-side flaws of ferromagnetic plates. In addition, using the proposed method, back-side flaws of ferromagnetic plates were evaluated with the phase change of the measured signals of the pick-up coil.

[1]  Hiroshi Hoshikawa,et al.  Characteristics of remote-field eddy current technique , 1988 .

[2]  Gui Yun Tian,et al.  Pulsed magnetic flux leakage techniques for crack detection and characterisation , 2006 .

[3]  N. Kasai,et al.  The Residual Magnetic Flux Leakage Technique for Surface Flaws with the Magneto-Impedance Sensor and Wavelet Analysis , 2006 .

[4]  H. Fukutomi,et al.  Remote field eddy current technique applied to non-magnetic steam generator tubes , 2001 .

[5]  Shinsuke Watanabe,et al.  Magnetic leakage field due to sub-surface defects in ferromagnetic specimens , 1995 .

[6]  Naoya Kasai,et al.  Non-destructive evaluation method for far-side corrosion type flaws in oil storage tank bottom floors using the magnetic flux leakage technique , 2003 .

[7]  Derek P. Atherton.  The application of finite-element calculations to the remote-field inspection technique , 1987 .

[8]  Satish Udpa,et al.  Remote field eddy current testing for detection of stress corrosion cracks in gas transmission pipelines , 2004 .

[9]  D. M. Amos.  Magnetic flux leakage as applied to aboveground storage tank flat bottom tank floor inspections , 1996 .

[10]  D. L. Atherton,et al.  The remote-field through-wall electromagnetic inspection technique for pressure tubes , 1986 .

[11]  David L. Atherton,et al.  A remote-field eddy current tool for inspecting nuclear reactor pressure tubes , 1988 .

[12]  Calculation of magnetostatic field around far side defects for nondestructive testing , 1995 .

[13]  S B Palmer,et al.  The magnetic leakage field of surface-breaking cracks , 1986 .

[14]  T. R. Schmidt.  The remote field eddy current inspection technique , 1984 .