GRAIN ORIENTED SILICON STEEL SHEET EXCELLENT IN FILM CHARACTERISTIC AND PRODUCING METHOD THEREFOR

摘要

PURPOSE: A grain oriented silicon steel sheet is provided to realize a tension applying effect higher than that by the conventional method and to exhibit excellent adhesion and magnetic properties and moreover excellent corrosion resistance which allows the same to withstand the practical use with a high occupying volume ratio. CONSTITUTION: A grain oriented silicon steel sheet has an insulating film composed of a layer essentially consisting of the hydrogen phosphate of a bivalent or trivalent metal and silica as a first layer and a layer essentially consisting of aluminum borate whose surface roughness is controlled to 0.1 to 0.50 microns by Ra (center line average roughness) as a second layer on the surface.