Theoretical analysis of Barkhausen noise in carbon steels

Abstract

This paper describes the theoretical analysis of Barkhausen noises initiated in two different microstructures of carbon steels, being consisted of ferrite grains with or without dispersed cementites. The Barkhausen noise is generally evaluated by its RMS value, which is the sum of induced voltage pulses caused by the magnetic flux change in each microregion. In this paper an induced voltage pulse is approximated by a gaussian pulse. The theoretical relationships between RMS values of Barkhausen noises and the microstructures of carbon steels are as follows, (RMS)=Cg.dg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> in ferrite grains and (RMS)=Cp.dp <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in cementite-dispersed ferrite grains, where dg and dp are ferrite grain size and cementite particle diameter, respectively. Cg and Cp are constant.