GRAIN-ORIENTED ELECTRICAL STEEL SHEET, GRAIN-ORIENTED ELECTRICAL STEEL SHEET PRODUCTION METHOD, GRAIN-ORIENTED ELECTRICAL STEEL SHEET EVALUATION METHOD AND IRON CORE

摘要

A grain oriented electrical steel sheet has a forsterite film on a steel sheet, and the forsterite film as viewed from above the surface has a total area percentage of defective parts scattered on the film of less than 1.5% relative to the surface area of the forsterite layer. In the invention, it is preferable that at least part of the defective parts be streaky.;A method is provided for evaluating a grain oriented electrical steel sheet having a forsterite film on a steel sheet to estimate the adhesion between the forsterite film and the surface of the steel sheet, the method including irradiating an electron beam to the surface of the grain oriented electrical steel sheet, dispersing the consequent emission into a spectrum, and evaluating the adhesion between the forsterite film and the surface of the steel sheet using at least one of the intensity of emission peak A and/or emission peak B observed at 380 to 600 nm wavelengths, and the intensity ratio of these peaks.