A Magnetic Head for Detecting Barkhausen Noise

Abstract

A Magnetic Head with high S/N ratio, for detecting Barkhausen Noise (BHN) of ferromagnetic steels, has been developed. This magnetic head has two characteristics. Namely, the BHN signals can be detected under conditions of (a) the induction search coil being lifted off from the surface of the steel at a distance of as large as 4mm, and (b) without using a frequency filtering device which is required in a conventional method. We analyzed the performance of the magnetic head on the basis of the magnetic flux density distribution around the search coil.
This magnetic head can be applied for evaluating microstructures, stress and mechanical properties of the steels nondestructively not only in a steel manufacturing process but also in a paint coating and/or rusty conditions.