METHOD FOR PRODUCING LOW CORE LOSS GRAIN-ORIENTED MAGNETIC STEEL SHEET AND METHOD FOR FINISH-ANNEALING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a grain-oriented magnetic steel sheet and a method for finish-annealing the same, with which a core loss is reduced by flattening the surface of the steel sheet.;SOLUTION: In the method for producing the grain-oriented magnetic steel sheet, prescribed annealing and rolling are applied, annealing parting agent is coated, and the finish-annealing is applied to a steel slab containing 2.0-7.0 mass% Si, the annealing parting agent has a composition containing metallic oxide etc. in which total of magnesia has presence ratio of ≥20 mass%, and the metallic chloride etc., at the ratio in which the total of chlorine, bromine, and iodine is 0.1-10 parts by mass to the 100 parts by mass of the metallic oxide etc. The finish-annealing is performed in an atmosphere having 0-25 vol.% low hydrogen ratio in a first temperature range raising the temperature to a specific temperature and is performed under atmosphere having 25 vol.% high hydrogen ratio in a second temperature range raising the temperature to not lower than the specific temperature, and soaking and holding the temperature.;COPYRIGHT: (C)2004,JPO&NCIPI