LOW IRON LOSS GRAIN ORIENTED SILICON STEEL SHEET FREE FROM DETERIORATION IN CHARACTERISTIC BY STRESS RELIEF ANNEALING AND ITS PRODUCTION

摘要

PURPOSE:To delineate and form a heterogeneous region in a film and to decrease the deterioration in the characteristics after stress relief annealing by forming locally a liquid-repellent insulating film on the surface of a grain oriented silicon steel sheet subjected to finish annealing then forming an insulation coating thereon. CONSTITUTION:The insulating film consisting of a borosiloxane resin, etc. which has liquid repellency to a coating treatment liquid repellency to a coating treatment liquid and is of a non-tension applying type is locally formed on the surface of the grain oriented silicon steel sheet which has the uniform forsterite film and is subjected to the finish annealing. The insulation coating liquid of a tension applying type is then coated thereon and is baked. the heterogeneous region which does not contribute to the tension application to the base iron is delineated and formed in the tension applying type insulation coating film by such baking. A different tension region is generated on the steel sheet surface by such heterogeneous region but an elastic strain is incorporated into the steel sheet surface by such different tension, by which the magnetic domains are eventually segmented. The grain oriented silicon steel sheet having the improved iron loss characteristic is thus obtd.