A new MFL principle and method based on near-zero background magnetic field

Abstract On the basis of the analysis of the MCE (magnetic compression effect) in present MFL (magnetic flux leakage) applications, a new MFL principle and technique based on the establishment of a near-zero background magnetic field is proposed for the first time, resulting in an increase of MFL allowing a non-contact MFL signal pick-up at larger probe lift-off. Afterwards, the feasibility of the proposed principle is justified by simulations and experiments. Finally, their advantages are presented. By applying the proposed MFL principle, the severe wear of contact probes can be avoided and inspection at high-temperature heat pipes can be performed. The contributions of the technique to reduce magnetic noise, distortion and the saturation of hall sensors are also discussed.

[1]  Gui Yun Tian,et al.  3D magnetic field sensing for magnetic flux leakage defect characterisation , 2006 .

[2]  Numerical Modeling of a Magnetic Flux Compression Experiment , 2007 .

[3]  Yong Zhang,et al.  An adaptive method for channel equalization in MFL inspection , 2007 .

[4]  David L. Atherton,et al.  A study of magnetic flux-leakage signals , 1998 .

[5]  Kang Yihua,et al.  Tubing thread inspection by magnetic flux leakage , 2006 .

[6]  Anthony John Moses,et al.  FEM modelling techniques of magnetic flux leakage-type NDT for ferromagnetic plate inspections , 2006 .

[7]  Gui Yun Tian,et al.  Numerical simulation on magnetic flux leakage evaluation at high speed , 2006 .

[8]  R. K. Stanley,et al.  Dipole Modeling of Magnetic Flux Leakage , 2009, IEEE Transactions on Magnetics.

[9]  A. Wilmot-Smith,et al.  Magnetic diffusion and the motion of field lines , 2005 .

[10]  M. P. Janawadkar,et al.  Defect localization by orthogonally projected multiple signal classification approach for magnetic flux leakage fields , 2008 .

[11]  E. Parker.  Compression of magnetic field in a viscous boundary layer , 1982 .

[12]  Ruan Jiangjun,et al.  3-D FEM Simulation of Velocity Effects on Magnetic Flux Leakage Testing Signals , 2008, IEEE Transactions on Magnetics.

[13]  G. Park,et al.  Improvement of the sensor system in magnetic flux leakage-type nondestructive testing (NDT) , 2002 .

[14]  Asa Prateepasen,et al.  Design of modified electromagnetic main-flux for steel wire rope inspection , 2009 .

[15]  E. Maréchal,et al.  Magnetic compression of a falling cold atom cloud , 1999 .

[16]  Changlong Wang,et al.  LS-SVMs-based reconstruction of 3-D defect profile from magnetic flux leakage signals , 2007 .

[17]  Shau-Wei Hsu.  Analysis of errors in obtaining magnetic dipoles based on magnetic field distribution , 2006 .

[18]  F. Förster.  New findings in the field of non-destructive magnetic leakage field inspection , 1986 .

[19]  G. P. Srivastava,et al.  Characterisation of metal loss defects from magnetic flux leakage signals with discrete wavelet transform , 2000 .

[20]  David L. Atherton,et al.  Finite element calculation of magnetic flux leakage detector signals , 1987 .

[21]  Lynann Clapham,et al.  Mechanical damage detection using magnetic flux leakage tools: modeling the effect of dent geometry and stresses , 2005 .

[22]  Kazumasa Nishio,et al.  The influence of modeled B–H curve on the density of the magnetic leakage flux due to a flaw using yoke-magnetization , 2004 .