3-dimensional magnetic leakage field sensor in nondestructive testing

The magnetic leakage flux method is one of the commonest non-destructive methods used for finding defects or inhomogeneities in steel products, e.g. the welding line in ferromagnetic steel. The quality of welded tubes has improved in recent years so that the signal detected by the one dimensional magnetic leakage flux sensor generated by the welding line has similar amplitude to the signal generated by the inhomogeneities in the materials of the tube wall. The paper shows that the use of a three-dimensional magnetic leakage flux sensor in conjunction with a rule-based fuzzy classificator significantly improves welded-seam inspection.