Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO.sub.2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO.sub.2; and H.sub.3PO.sub.4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy:
0.20([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]0.45(1).

Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO.sub.2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO.sub.2; and H.sub.3PO.sub.4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy:
0.20([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]0.45(1).

A grain oriented electrical steel sheet comprising a grain oriented electrical steel sheet having a surface and a forsterite film formed on the surface of the steel sheet, wherein a total area percentage of defective parts scattered on the forsterite film is less than 1.5% relative to a surface area of the forsterite film when viewed from above the surface, and methods for evaluating a grain oriented electrical steel sheet comprising a grain oriented electrical steel sheet having a surface and a forsterite film formed on the surface of the steel sheet.

To provide a grain-oriented electrical steel sheet that has better magnetic property than conventional ones without requiring high-temperature slab heating, in the case of not performing intermediate annealing, the hot rolled steel sheet obtained by a predetermined step is subjected to hot band annealing, and, in a heating process in the hot band annealing, heating is performed at a heating rate of 10? C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700? C. or more and 950? C. or less, and in the case of performing the intermediate annealing, in a heating process in final intermediate annealing, heating is performed at a heating rate of 10? C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700? C. or more and 950? C. or less.

There is provided a grain-oriented electrical steel sheet stably having excellent magnetic characteristics and coating adhesion even when a rapid heating is conducted in a primary recrystallization annealing (decarburization annealing). Concretely, it is a grain-oriented electrical steel sheet provided on its sheet surface with a tension-applying type insulation coating constituted with a coating layer A formed on a steel sheet side and mainly composed of an oxide and a coating layer B formed on a surface side and mainly composed of glass, characterized in that a ratio R (.sub.B/.sub.A) of a tension .sub.B of the coating layer B on the surface side applied to the steel sheet to a tension .sub.A of the coating layer on the steel sheet side A applied to the steel sheet is within a range of 1.20-4.0.

Provided are: an oriented electromagnetic steel sheet with outstanding coating adhesion and magnetic properties after stress relief annealing; and a method for manufacturing the oriented electromagnetic steel sheet. The oriented electromagnetic steel sheet comprises: a steel sheet; a non-oxide ceramic coating disposed on the steel sheet and containing a non-oxide; and an insulating tensile coating disposed on the non-oxide ceramic coating and containing an oxide. The thickness of the non-oxide ceramic coating is 0.020-0.400 m. The thickness of the insulating tensile coating is at least 1.0 m. The chromium content on the steel plate side of the non-oxide ceramic coating is less than 25 atomic %, and the chromium content on the insulating tensile coating side of the non-oxide ceramic coating is at least 25 atomic %.

This grain-oriented electrical steel sheet includes: a base steel sheet; and an insulating coating formed on a surface of the base steel sheet, in which the base steel sheet includes an iron-based oxide layer containing an iron-based oxide on an insulating coating side, the insulating coating includes an intermediate layer formed on a base steel sheet side and containing a crystalline metal phosphate, and a tension coating layer formed on a surface side of the insulating coating, an average thickness of the iron-based oxide layer is 0.10 to 1.50 ?m, an average thickness of the intermediate layer is 0.3 to 10.0 ?m, an average thickness of the insulating coating is 2.0 to 10.0 ?m, the crystalline metal phosphate of the intermediate layer is one or two or more of zinc phosphate, manganese phosphate, iron phosphate, and zinc calcium phosphate, the tension coating layer contains a metal phosphate and silica, and an amount of the silica in the tension coating layer is 20 to 60 mass %.

This grain-oriented electrical steel sheet includes a base steel sheet, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, in the base steel sheet, a plurality of linear strains that extend continuously or intermittently in a direction intersecting with a rolling direction are present, and intervals in the rolling direction of the plurality of linear strains adjacent to each other are 10 mm or less, in a region where the strains are present, a closure domain is present, a length d of the closure domain in a sheet thickness direction from a surface of the base steel sheet is 30 to 60 ?m, a length w in the rolling direction is 200 ?m or less, and a ratio mid of a depth m from the surface of the base steel sheet where a compressive strain in the rolling direction present in the closure domain exhibits a maximum value to the length d is in a range of more than 0.30 and less than 0.90.

This grain-oriented electrical steel sheet includes a base steel sheet, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, in which, in the base steel sheet, a plurality of linear strain regions that extend continuously or intermittently in a direction intersecting with a rolling direction are present, the plurality of linear strain regions are each 210 ?m or less in width in the rolling direction, the plurality of linear strain regions are parallel to each other, intervals of linear strain regions adjacent to each other in the rolling direction are 10 mm or less, and magnetostriction ?.sub.0-pb in a unit of ?m/m when the grain-oriented electrical steel sheet is excited up to 1.7 T and magnetostriction ?.sub.0-pa in a unit of ?m/m when the grain-oriented electrical steel sheet is heat-treated at 800? C. for 4 hours and then excited up to 1.7 T satisfy 0.02??.sub.0-pb??.sub.0-pa?0.20.

This grain-oriented electrical steel sheet includes a base steel sheet having a predetermined chemical composition, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, on a front surface of the base steel sheet, a plurality of linear strains that extend continuously or intermittently in a direction intersecting with a rolling direction are present, intervals p in the rolling direction of the plurality of linear strains adjacent to each other are 3.0 to 9.0 mm, widths of the linear strains are 10 to 250 ?m, and, in an X-ray topographic spectrum in a range of 1.50 mm in the rolling direction that is obtained from an X-ray topographic image of the front surface and includes the linear strain at a center, a full width at half maximum of a peak of the X-ray topographic spectrum including a maximum value of a spectral intensity is 0.02 mm or more and 0.10 mm or less.