Method and apparatus for leakage flux testing

Abstract

In a method for leakage flux testing of ferromagnetic material to be tested, in particular ferromagnetic pipes, for detecting defects, a testing volume of the material to be tested is magnetized by a constant magnetic field. A surface of the material to be tested is scanned by a probe arrangement for capturing magnetic leakage fields caused by defects. The probe arrangement has a probe array with a multiplicity of magnetic-field-sensitive probes arranged next to one another in a first direction and held at a finite testing distance from the surface of the material to be tested during the testing. Electrical probe signals are evaluated for qualifying the defects. Use is made of a probe arrangement in which the probes each have a probe width in the first direction which lies in the range from 20% of the testing distance up to 10 mm. An evaluation of the probe signals includes a mapping operation, in which signal information representing the probe signal is linked to spatial information representing the creation location of a probe signal for each probe signal in order to form spatially dependent signal data, a matrix-forming operation, in which the spatially dependent signal data, or signal data derived therefrom, are stored in fields, assigned with the correct location, of a basis matrix, and at least one evaluating operation, in which spatially dependent signal data from at least two fields of the basis matrix, directly or indirectly adjacent to one another in an evaluating direction, are linked to one another using at least one evaluating algorithm.

Dependencies are inferred from the claim text.