Method and apparatus for testing ferromagnetic work pieces by ultrasonic waves

Abstract

Abstract The invention relates to a method and test apparatus incorporating a magnet system for testing ferromagnetic workpieces by ultrasonic waves, in which an alternating magnetic field (B &tilde& ) aligned parallel to the surface in the test body is produced by means of a magnet system (10, 11) applied to the surface (15) of a ferromagnetic workpiece and excited with alternating current and high-frequency transmission pulses are triggered in the region of the maximum amplitude of the magnetic field strength by a transducer coil (14) mounted in the vicinity of the surface of the workpiece. In order to test ferromagnetic workpieces for faults on the one hand at various predetermined angles and, on the other hand, as an alternative, to be able also to determine the thickness of the workpiece in addition, the invention proposes that a magnetic field (B ORTHOGONAL ) of quasi-static polarity aligned vertically with respect to the surface of the workpiece and produced with the magnet system (13) is generated and superimposed in the alternating magnetic field and that, regardless of a desired acoustic radiation direction, high-frequency transmission pulses are triggered either only in the region of the upper half wave or only in the region of the lower half wave of the alternating current. <IMAGE>

Inventors

• 👤 Alfred Dipl.-Phys. Graff
• 👤 Michael Dr.rer.nat. Wächter

Bibliographic Details