Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.

Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.

A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1): M.sup.II.sub.3M.sup.III.sub.4(X.sup.VO.sub.4).sub.6 . . . (1). A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900° C. in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0° C.

An electrical steel sheet having an insulating coating is provided. The electrical steel sheet is capable of reducing dielectric loss in a transformer in a case where the electrical steel sheet is used in a transformer core.

An electrical steel sheet having an insulating coating, the insulating coating being disposed on at least one of surfaces of the electrical steel sheet, the insulating coating having a relative dielectric constant at 1000 Hz of less than or equal to 15.0 and a dielectric loss tangent at 1000 Hz of less than or equal to 20.0.

An electrical steel sheet having an insulating coating is provided. The electrical steel sheet is capable of reducing dielectric loss in a transformer in a case where the electrical steel sheet is used in a transformer core.

An electrical steel sheet having an insulating coating, the insulating coating being disposed on at least one of surfaces of the electrical steel sheet, the insulating coating having a relative dielectric constant at 1000 Hz of less than or equal to 15.0 and a dielectric loss tangent at 1000 Hz of less than or equal to 20.0.

An object of the present invention is to provide a treatment liquid and a treatment method that are capable of enhancing the corrosion resistance of a net material. This object is achieved by, after forming a chemical conversion treatment film on the surface of a metal material, forming a film using a film-forming treatment liquid, the treatment liquid comprising: a silicon compound containing at least one member selected from the group consisting of alkoxysilyl, alkoxysilylene, and a siloxane bond; an organometallic compound; and water.

Provided is a surface treated steel sheet for a fuel tank, the surface treated steel sheet including: a Zn plated layer or a ZnNi alloy plated layer which is formed on at least a surface of the steel sheet to be an inner surface of the fuel tank; and a chromate-free chemical conversion coating layer containing a water-and-oil repellent, the chromate-free chemical conversion coating layer being placed over the Zn plated layer or the ZnNi alloy plated layer on the surface to be the inner surface of the fuel tank. A water contact angle on a surface of the chromate-free chemical conversion coating layer is more than or equal to 70 degrees and an n-hexadecane contact angle on the surface of the chromate-free chemical conversion coating layer is more than or equal to 30 degrees and less than or equal to 70 degrees.

Provided is a surface treated steel sheet for a fuel tank, the surface treated steel sheet including: a Zn plated layer or a ZnNi alloy plated layer which is formed on at least a surface of the steel sheet to be an inner surface of the fuel tank; and a chromate-free chemical conversion coating layer containing a water-and-oil repellent, the chromate-free chemical conversion coating layer being placed over the Zn plated layer or the ZnNi alloy plated layer on the surface to be the inner surface of the fuel tank. A water contact angle on a surface of the chromate-free chemical conversion coating layer is more than or equal to 70 degrees and an n-hexadecane contact angle on the surface of the chromate-free chemical conversion coating layer is more than or equal to 30 degrees and less than or equal to 70 degrees.

A coating solution for forming an insulating film for a grain-oriented electrical steel sheet which contains one or more types of hydrous silicate powders having an average particle size of 2 m or less, and one or more types of phosphoric acids and phosphates satisfying a relation of n.sub.iM.sub.i/P.sub.i0.5, and satisfies (Formula 1). 1.5(n.sub.iM.sub.i+n.sub.jM.sub.j)/P.sub.i15 . . . (Formula 1) (P represents the number of moles of phosphorus, M represents the number of moles of metal ions derived from the phosphate, n represents the valence of the metal ions derived from the phosphate, i represents the number of types of phosphates, M represents the number of moles of metal elements in the hydrous silicate, n represents the valence of the metal elements in the hydrous silicate, and j represents the number of types of hydrous silicates).

Aqueous compositions useful as a passivation treatment prior to painting to reduce corrosion. The compositions includes water, a trivalent chromium salt with the formula Cr(H.sub.xPO.sub.4).sub.3, where x is 1.5 or 2, a polymer system having a plurality of carboxylic functional groups, an organo-functional silane, and an organopolyphosphonic acid. A process for treating a metal surface includes contacting the surface with such aqueous compositions. The compositions and the processes provide benefits in comparison to the zinc phosphate metal pretreatment thought to be the standard in the industry.