Abstract: Nitriding process of a steel strip is performed. Next, annealing is performed to form a forsterite based glass coating film at a surface of the steel strip. Heating is performed up to 1000° C. or more in a mixed gas atmosphere containing H2 gas and N2 gas, and a rate of N2 gas is 20 volume % or more, next, the atmosphere is switched into H2 gas atmosphere at the temperature of 1000° C. or more and 1100° C. or less, when the annealing is performed. An oxygen potential P (H2O)/P (H2) is set to be 0.05 to 0.3 when the temperature is 850° C. or less during the heating in the mixed gas atmosphere.

Abstract: This oriented electrical steel sheet is a non-oriented electrical steel sheet consisting of, in mass %: C: not less than 0.0001% and not more than 0.0040%, Si: more than 3.0% and not more than 3.7%, sol.Al: not less than 0.3% and not more than 1.0%, Mn: not less than 0.5% and not more than 1.5%, Sn: not less than 0.005% and not more than 0.1%, Ti: not less than 0.0001% and not more than 0.0030%, S: not less than 0.0001% and not more than 0.0020%, N: not less than 0.0001% and not more than 0.003%, Ni: not less than 0.001% and not more than 0.2%, P: not less than 0.005% and not more than 0.05%, with a balance consisting of Fe and impurities, in which a resistivity ? at room temperature ?60 ??cm, and saturation magnetic flux density Bs at room temperature ?1.945 T are established, and the components contained satisfy 3.5?Si+(?)×sol.Al+(?)×Mn?4.25.

Abstract: A grain-oriented electrical steel sheet has a tension film that does not include chromium. In the present invention, the tension film, including a phosphate and silica as constituents, includes a manganese compound and a potassium compound. The mole ratio K/Mn of potassium to manganese in the film is set to a certain range. The film can be produced by preparing a coating solution by adding a compound, which includes the phosphate and the silica and also includes the potassium and the manganese, and applying the coating solution on a grain-oriented electrical steel sheet after final annealing is completed, followed by drying and baking.

Abstract: Nitriding process of a steel strip is performed. Next, annealing is performed to form a forsterite based glass coating film at a surface of the steel strip. Heating is performed up to 1000° C. or more in a mixed gas atmosphere containing H2 gas and N2 gas, and a rate of N2 gas is 20 volume % or more, next, the atmosphere is switched into H2 gas atmosphere at the temperature of 1000° C. or more and 1100° C. or less, when the annealing is performed. An oxygen potential P (H2O)/P (H2) is set to be 0.05 to 0.3 when the temperature is 850° C. or less during the heating in the mixed gas atmosphere.

Abstract: A grain-oriented electrical steel sheet has a tension film that does not include chromium. In the present invention, the tension film, including a phosphate and silica as constituents, includes a manganese compound and a potassium compound. The mole ratio K/Mn of potassium to manganese in the film is set to a certain range. However, the manganese described herein does not refer to manganese derived from a manganese phosphate included in raw materials of the film. The film can be produced by preparing a coating solution by adding a compound, which includes the phosphate and the silica and also includes the potassium and the manganese, and applying the coating solution on a grain-oriented electrical steel sheet after final annealing is completed, followed by drying and baking.