The magnetovision method as a tool to investigate the quality of electrical steel

Abstract

This paper presents a new method for testing electrical steel sheet, based on measurements of the magnetic field distribution over the sheet surface. The tangential field value is measured with the aid of a permalloy magnetoresistive sensor. The field distribution is displayed in the form of a colour map, hence the method is called `magnetovision'. The repeatability of the maps is excellent. The most interesting new results of electrical steel investigations are presented. The system provides a versatile tool for non-destructive quality control and for the determination of the structural uniformity of electrical steel. Magnetovision, compared with other methods, seems to be especially useful for detecting the causes of steel quality deterioration.