METHOD OF FORMING INSULATING FILM OF GRAIN-ORIENTED SILICON STEEL SHEET HAVING EXCELLENT MAGNETIC PROPERTY AND EXCELLENT ADHESION OF COATING

摘要

PROBLEM TO BE SOLVED: To provide a method of producing a grain-oriented silicon steel sheet having good adhesion of a coating and a low iron loss, which is applied to an annealed grain-oriented silicon steel coil coated with no inorganic mineral film on its surface. SOLUTION: The method of producing the grain-oriented silicon steel sheet is characterized in that before forming an insulating film capable of imparting a tensile force, the finish annealed grain-oriented silicon steel sheet is subjected to a heat treatment such that the temperature of the steel sheet is >=800 and >=1,150 deg.C and the tensile force applied to the steel plate is <=9.8 MPa so as to form an oxide film on the surface of the steel sheet.