EFFECTS OF MAGNETIC FLUX DENSITY AND TENSILE STRESS ON THE MAGNETIC BARKHAUSEN NOISE IN PIPELINE STEEL

Abstract Magnetic Barkhausen noise ( MBN) measurements were made on a sample of pipeline steel to study the effect of magnetic flux density on the tensile stress dependence of MBN. The results suggest that MBN activity generally increases with flux density but begins to decrease slightly at higher flux densities. Similar behaviour is found at all tensile stress levels both when the stress is parallel and perpendicular to the applied field. The stress dependence of the MBN also shows a strong dependence on the flux density. However, at high flux density when the magnetic field is perpendicular to the stress, the MBN rms voltage saturates with increasing stress. These results are explained in terms of domain wall dynamics by considering the effect of the relative orientations of the magnetic flux density and applied tensile stress with respect to the easy axis of magnetization of the sample. KEY WORDS: Barkhausen noisemagneticpipeline steelstresstensionflux density