Method and device for the nondestructive testing of ferromagnetic bodies by magnetisation

摘要

In a method and a device for the nondestructive testing of ferromagnetic bodies by magnetising the body concerned, microstructure defects produce alterations in the pattern of the magnetic field in the body. The alterations are detected by magnetic gradient probes (24) situated at or near the surface of the body concerned. At least two electromagnets (10, 12) having a common limb or adjacently situated limbs (20, 22) are situated so as to be offset with respect to one another at an angle which is different from 180@. The gradient probes (24) are situated in the centre between the limbs (20, 22) of the electromagnets. The coils (18) of the electromagnets are connected to a switching device which alternately connects the coils to a power source. <IMAGE>