METHOD FOR MANUFACTURING GRAIN-ORIENTED ELECTRICAL STEEL SHEET

• Main Authors: TAKAHASHI, Masaru, USHIGAMI, Yoshiyuki, ZAIZEN, Yoichi, YASUDA, Masato, NAGANO, Shohji
• Format: Patent
• Language: English
• Published: 31.03.2022
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CHEMISTRY; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; INDUCTANCES; MAGNETS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

A method for manufacturing a grain-oriented electrical steel sheet includes: heating a steel slab having a prescribed chemical composition to lower than 1250° C. and subjecting the steel slab to hot rolling to obtain a hot-rolled steel sheet; performing hot-band annealing on the hot-rolled steel sheet; pickling the hot-rolled steel sheet which has been subjected to the hot-band annealing; subjecting the hot-rolled steel sheet which has been subjected to the pickling to cold rolling to obtain a cold-rolled steel sheet having a final sheet thickness d of 0.15 to 0.23 mm; performing a decarburization nitriding treatment including decarburization annealing and nitriding on the cold-rolled steel sheet; performing final annealing on the cold-rolled steel sheet which has been subjected to the decarburization nitriding treatment; and then applying a coating liquid for insulation coating formation to the cold-rolled steel sheet which has been subjected to the final annealing and baking the cold-rolled steel sheet. Sol. Al/N which is a mass ratio between Sol. Al and N in the steel slab and the final sheet thickness d satisfy a prescribed relational expression, the N content of the cold-rolled steel sheet which has been subjected to the decarburization nitriding treatment is 40 to 1000 ppm, and a decarburization annealing temperature in the decarburization annealing is lower than 1000° C.