Magnetic losses reduction in grain oriented silicon steel by pulse and continuous fiber laser processing

Ivan Petryshynets,Ján Füzer,Peter Kollár,Viktor Puchý,Martin Šebek,František Kováč

doi:10.1063/1.4994191

Abstract

The present paper shows the impact of different laser scribing conditions on possible reduction of magnetic losses in grain oriented electrical steel sheets. The experimental Fe-3%Si steel was taken from industrial line after final box annealing. The surface of investigated steel was subjected to fiber laser processing using both pulse and continuous scribing regimes in order to generate residual thermal stresses inducing the magnetic domains structure refinement. The magnetic losses of experimental samples before and after individual laser scribing regimes were tested in AC magnetic field with 50Hz frequency and induction of 1.5T. The most significant magnetic losses reduction of 38% was obtained at optimized conditions of continuous laser scribing regime. A semi quantitative relationship has been found between the domain patterns and the used fiber laser processing.

Highlights

As an aspect of the worldwide trend towards energy consumption and preservation of the natural environment, the reduction of electricity consumption has become an extremely crucial matter in recent years
The common microstructure and texture of the experimental GO steel which was taken from industrial line after final treatment is presented by Inverse Pole Figure (IPF) map as well as Orientation Distribution Function (ODF), see figure 2(a) and 2(b), respectively
The IPF map as well as the ODF section taken at φ2=0◦ show that the presented grain matrix is formed by the grains with preferable {110} Goss crystallographic orientation

Summary

Introduction

As an aspect of the worldwide trend towards energy consumption and preservation of the natural environment, the reduction of electricity consumption has become an extremely crucial matter in recent years. Grain-oriented (GO) silicon steel represents conventional soft magnetic material having high permeability and low core losses along the rolling direction and is commonly used for cores of electric transformers. The procedure has been continuously improved and developed in order to achieve the best final properties of the material. In the last few years, these aspects have become the mainspring for most of the industrial research and development activities.[4] Improvements in the magnetic properties of electrical steels over the past 80 years have resulted from the control of impurities, thinner strips, improved coatings, improved texture and optimization of grain size.[5] It is likely that trend will continue and will lead to further incremental improvements. Magnetic domain structures of secondary recrystallized grains and especially their movement have a strong effect on the core losses of GO silicon steel. Pinning of domain walls movement and surface closure domains must be considered in order to reduce the magnetic losses of GO steel.[5]

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Conclusion