Asymmetrical Barkhausen Noise of a Hard Milled Surface

Abstract

This study is focused on the asymmetrical Barkhausen noise emission of a hard milled surface during cyclic magnetisation. The Barkhausen noise is studied as a function of the magnetising voltage and the hard milled surface is compared with a surface after heat treatment. The asymmetry in the Barkhausen noise emission after hard milling occurs due to the typical “sandwich” structure and the different magnetic hardnesses of the different layers beneath the free surface. Furthermore, this asymmetry is also due to the preferential orientation of the matrix in the direction of the cutting speed and magnetostatic fields, which hinder or favour the premagnetising process.

Investigation of Magnetic Anisotropy and Barkhausen Noise Asymmetry Resulting from Uniaxial Plastic Deformation of Steel S235

“…The authors separated the individual contributions of each layer into the global magnetic behaviour and analysed the magneto-coupling between them. The findings of this study match well with the magnetic behaviour of the hard-milled surface when the magnetic coupling can be found between the surface hard white layer and the subsurface soft heat-affected region [18]. The marked MBN asymmetry was also reported during uniaxial plastic straining [12].…”

“…This hinders the positive saturation and favours the negative one. A graphical illustration further explaining the aforementioned effect can be found in [18,22]. The sample history with respect to its magnetic anisotropy in the RD plays a significant role since the aforementioned effect occurs in the RD only, and vanishes towards the TD.…”

“…Sensitivity of MBN against dislocation density and phase transformations has been investigated and explained in a satisfactory manner. On the other hand, such aspects as the alteration of magnetic anisotropy or/and the asymmetry in MBN bursts have been reported [12,18], but their origin has not been satisfactorily discussed and explained yet. It is considered that the alterations of magnetic anisotropy are due to realignment of DWs due to the preferential crystallographic orientation [18][19][20][21].…”

“…On the other hand, such aspects as the alteration of magnetic anisotropy or/and the asymmetry in MBN bursts have been reported [12,18], but their origin has not been satisfactorily discussed and explained yet. It is considered that the alterations of magnetic anisotropy are due to realignment of DWs due to the preferential crystallographic orientation [18][19][20][21]. On the other hand, remarkable asymmetry in the consecutive MBN bursts in many cases is due to residual magnetism.…”

Examining Ferromagnetic Materials Subjected to a Static Stress Load Using the Magnetic Method

“…I the Barkhausen noise method relies on observing the magnetization process, which causes the dipoles to rotate [14][15][16]. If the material contains inhomogeneities, the process of domain wall shifting will be disrupted.…”