Method and apparatus for detecting defects in workpieces using a core-type magnet with magneto-sensitive detectors

摘要

A method is proposed by which defects in workpieces are detected magnetically, which method comprises the following steps being performed concurrently: scanning the test surface of a workpiece utilizing magneto-sensitive elements; magnetizing the workpiece perpendicularly to its test surface in the test zone; exciting magneto-sensitive elements; and measuring the tangential component of the magnetic field strength in the test zone. An apparatus for magnetically detecting defects in workpieces according to the proposed method comprises an electrical signal excitation/measuring unit and a detector. The latter has a housing which accommodates a core-type magnet rigidly fixed to it and adapted to be magnetized prependicularly to its working surface which mounts magneto-sensitive elements separated from each other and oriented in a prescribed manner. The elements connect each other and the electrical signal excitation/measuring unit as well.