ANISOTROPY OF STEEL SHEETS AND CONSEQUENCE FOR EPSTEIN TEST: I THEORY

Marcos Flavio de Campos

Abstract

ODF – Orientation Distribution Function – Theory allow the prediction of the average magnetic properties of electrical steels when crystalline symmetry of cubic bcc iron and the orthorhombic sheet symmetry are taken into account. The crystallographic texture can be related to the magnetocrystalline anisotropy by means of a very simple expression. The dependence of the variables: Magnetic Induction, coercivity, permeability and iron losses with texture is discussed. Magnetic Induction at high fields - B₂₅ and B₅₀ - can be directly scaled to magnetocrystalline anisotropy. Effects of demagnetizing field on the Magnetic Induction are commented. Permeability and power losses are not directly related to magnetocrystalline anisotropy, mainly due the existence of domain wall displacement phenomena. The domain wall structure is function of the crystalline orientation and also contributes for the anisotropy of iron losses. As consequence of the theoretical analysis, it is suggested that the traditional Epstein arrangement (50% RD-Rolling Direction plus 50% TD–Transverse Direction), be changed for 3 separate measurements in the RD, TD (i.e., 90o) and 45° directions.

Keywords

electrical steels, anisotropy, magnetic induction, permeability, energy losses

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PWC-2006-TC4-037u.pdf

DOI

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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