Grain oriented electrical steel sheet, forming method for insulation coating of grain oriented electrical steel sheet, and producing method for grain oriented electrical steel sheet

A forming method for an insulation coating of a grain oriented electrical steel sheet without a forsterite film characterized in that

• the forming method for the insulation coating includes an insulation coating forming process of forming a tension-insulation coating on a steel substrate,
• wherein, in the insulation coating forming process,
• a solution for forming the tension-insulation coating is applied to an oxide layer of the steel substrate and the solution is baked,
• wherein the steel substrate includes a base steel sheet and the oxide layer arranged in contact with the base steel sheet,
• the base steel sheet includes, as a chemical composition, by mass %,
• 2.5 to 4.0% of Si,
• 0.05 to 1.00% of Mn,
• 0 to 0.01% of C,
• 0 to 0.005% of S+Se,
• 0 to 0.01% of sol. Al,
• 0 to 0.005% of N,
• 0 to 0.03% of Bi,
• 0 to 0.03% of Te,
• 0 to 0.03% of Pb,
• 0 to 0.50% of Sb,
• 0 to 0.50% of Sn,
• 0 to 0.50% of Cr,
• 0 to 1.0% of Cu, and
• a balance consisting of Fe and impurities,
• the oxide layer is an iron oxide layer, and
• when the iron oxide layer is analyzed by a fourier transform infrared spectroscopy, when A650 is an absorbance of an absorption peak detected at 650 cm−1 in an infrared absorption spectrum, and when A1250 is an absorbance of an absorption peak detected at 1250 cm−1 in the infrared absorption spectrum, the A650 and the A1250 satisfy 0.2≤A650/A1250≤5.0.

A grain oriented electrical steel sheet without a forsterite film characterized in that

• the grain oriented electrical steel sheet comprises:
• a base steel sheet;
• an oxide layer arranged in contact with the base steel sheet;
• and
• a tension-insulation coating arranged in contact with the oxide layer,
• wherein the base steel sheet includes, as a chemical composition, by mass %,
• 2.5 to 4.0% of Si,
• 0.05 to 1.00% of Mn,
• 0 to 0.01% of C,
• 0 to 0.005% of S+Se,
• 0 to 0.01% of sol.Al,
• 0 to 0.005% of N,
• 0 to 0.03% of Bi,
• 0 to 0.03% of Te,
• 0 to 0.03% of Pb,
• 0 to 0.50% of Sb,
• 0 to 0.50% of Sn,
• 0 to 0.50% of Cr,
• 0 to 1.0% of Cu, and
• a balance comprising Fe and impurities,
• the oxide layer is an iron oxide layer,
• when the iron oxide layer is analyzed by a fourier transform infrared spectroscopy, when A650 is an absorbance of an absorption peak detected at 650 cm−1 in an infrared absorption spectrum, and when A1250 is an absorbance of an absorption peak detected at 1250 cm−1 in the infrared absorption spectrum, the A650 and the A1250 satisfy 0.2≤A650/A1250≤5.0, and a magnetic flux density B8 in a rolling direction of the grain oriented electrical steel sheet is 1.90 T or more.

A forming method for an insulation coating of a grain oriented electrical steel sheet without a forsterite film characterized in that

• the forming method for the insulation coating includes an insulation coating forming process of forming a tension-insulation coating on a steel substrate,
• wherein, in the insulation coating forming process,
• a solution for forming the tension-insulation coating is applied to an oxide layer of the steel substrate and the solution is baked,
• wherein the steel substrate includes a base steel sheet and the oxide layer arranged in contact with the base steel sheet,
• the base steel sheet includes, as a chemical composition, by mass %,
• 2.5 to 4.0% of Si,
• 0.05 to 1.00% of Mn,
• 0 to 0.01% of C,
• 0 to 0.005% of S+Se,
• 0 to 0.01% of sol.Al,
• 0 to 0.005% of N,
• 0 to 0.03% of Bi,
• 0 to 0.03% of Te,
• 0 to 0.03% of Pb,
• 0 to 0.50% of Sb,
• 0 to 0.50% of Sn,
• 0 to 0.50% of Cr,
• 0 to 1.0% of Cu, and
• a balance comprising Fe and impurities,
• the oxide layer is an iron oxide layer, and
• when the iron oxide layer is analyzed by a fourier transform infrared spectroscopy, when A650 is an absorbance of an absorption peak detected at 650 cm−1 in an infrared absorption spectrum, and when A1250 is an absorbance of an absorption peak detected at 1250 cm−1 in the infrared absorption spectrum, the A650 and the A1250 satisfy 0.2≤A650/A1250≤5.0.