An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2), the insulating film (3) containing a polyvalent metal phosphate and Fe. A maximum value of a parameter Q expressed by Q=C.sub.FeO/C.sub.P is equal to or less than 1.3 times and equal to or more than 1.09 times an average value of the parameter Q in a region from a first depth from a surface of the insulating film to a second depth, C.sub.FeO denoting a proportion (atom %) of Fe bonded to O relative to all elements, and C.sub.P denoting a proportion (atom %) of P relative to all elements. The first depth is 20 nm from the surface, and the second depth is a depth where the proportion of P is equal to a proportion of metal Fe.

An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2), the insulating film (3) containing a polyvalent metal phosphate and Fe. A maximum value of a parameter Q expressed by Q=C.sub.FeO/C.sub.P is equal to or less than 1.3 times and equal to or more than 1.09 times an average value of the parameter Q in a region from a first depth from a surface of the insulating film to a second depth, C.sub.FeO denoting a proportion (atom %) of Fe bonded to O relative to all elements, and C.sub.P denoting a proportion (atom %) of P relative to all elements. The first depth is 20 nm from the surface, and the second depth is a depth where the proportion of P is equal to a proportion of metal Fe.

A steel sheet mainly suitable for strength members of automobiles or building materials, which has a tensile strength of 1,180 MPa or more, and which is excellent in delayed fracture resistance and primary rust prevention performance. The steel sheet includes a coating, placed on a surface of a cold-rolled steel sheet with a tensile strength of 1,180 MPa or more, containing one or more metalates selected from molybdates and tungstates and a P compound. The sum of the coating weights of the metalates in terms of Mo and W is 10 mg/m.sup.2 to 1,000 mg/m.sup.2 and is preferably 50 mg/m.sup.2 to 1,000 mg/m.sup.2. The coating weight of the P compound in terms of P is 10 mg/m.sup.2 to 1,000 mg/m.sup.2.

A steel sheet mainly suitable for strength members of automobiles or building materials, which has a tensile strength of 1,180 MPa or more, and which is excellent in delayed fracture resistance and primary rust prevention performance. The steel sheet includes a coating, placed on a surface of a cold-rolled steel sheet with a tensile strength of 1,180 MPa or more, containing one or more metalates selected from molybdates and tungstates and a P compound. The sum of the coating weights of the metalates in terms of Mo and W is 10 mg/m.sup.2 to 1,000 mg/m.sup.2 and is preferably 50 mg/m.sup.2 to 1,000 mg/m.sup.2. The coating weight of the P compound in terms of P is 10 mg/m.sup.2 to 1,000 mg/m.sup.2.

An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2). The insulating film (3) contains a phosphates of one or more selected from the group consisting of Al, Zn, Mg and Ca. The phosphate exhibits a specific peak having a top within a range of 26 ppm to 16 ppm in a solid .sup.31P-NMR spectrum, and a proportion of an integrated intensity of the specific peak relative to an integrated intensity of all peaks in the solid .sup.31P-NMR spectrum is 30% or more.

An electrical steel sheet (1) includes a base material (2) of electrical steel, and an insulating film (3) formed on a surface of the base material (2). The insulating film (3) contains a phosphates of one or more selected from the group consisting of Al, Zn, Mg and Ca. The phosphate exhibits a specific peak having a top within a range of 26 ppm to 16 ppm in a solid .sup.31P-NMR spectrum, and a proportion of an integrated intensity of the specific peak relative to an integrated intensity of all peaks in the solid .sup.31P-NMR spectrum is 30% or more.

A coating, a method for coating surfaces, and the coated surfaces. The method includes providing a substrate with a cleaned metal surface; contacting and coating the metal surface with an aqueous composition having a ph of from 0.5 to 7.0 and in the form of a dispersion and/or a suspension; optionally rinsing the organic coating; and drying and/or baking the organic coating, or optionally drying the organic coating and coating same with a similar or another coating composition thereto. The composition contains a complex fluoride in a quantity of 1.1 10.sup.6 mol/l to 0.30 mol/l based on the cations. An anionic polyelectrolyte in a quantity of 0.01 to 5.0 wt % based on the total mass of the resulting mixture is added to an anionically stabilized dispersion made of film-forming polymers and/or a suspension made of film-forming inorganic particles.

A coating, a method for coating surfaces, and the coated surfaces. The method includes providing a substrate with a cleaned metal surface; contacting and coating the metal surface with an aqueous composition having a ph of from 0.5 to 7.0 and in the form of a dispersion and/or a suspension; optionally rinsing the organic coating; and drying and/or baking the organic coating, or optionally drying the organic coating and coating same with a similar or another coating composition thereto. The composition contains a complex fluoride in a quantity of 1.1 10.sup.6 mol/l to 0.30 mol/l based on the cations. An anionic polyelectrolyte in a quantity of 0.01 to 5.0 wt % based on the total mass of the resulting mixture is added to an anionically stabilized dispersion made of film-forming polymers and/or a suspension made of film-forming inorganic particles.

An electrical steel sheet with an insulating film, the steel sheet having an insulating film containing a crystalline fibrous material on a surface of the steel sheet, in which a ratio (L.sub.RD/L.sub.TD) of a length in a rolling direction (L.sub.RD) of the crystalline fibrous material in a cross section in the rolling direction of the insulating film to a length in a direction perpendicular to the rolling direction (L.sub.TD) of the crystalline fibrous material in a cross section in the direction perpendicular to the rolling direction of the insulating film is 1.5 or more and 50.0 or less.

The invention relates to a steel substrate coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a conversion layer comprising: zincsulphate hydrate, aluminium in an amount up to 14 mg.Math.m.sup.?2, wherein the conversion layer comprises neither zinc hydroxysulphate, nor free water molecules nor any compounds having free hydroxyl groups, the surface density of sulphur in the conversion layer being greater than or equal to 5.0 mg/m.sup.2. The invention also relates to the corresponding treatment method.