A grain-oriented electrical steel sheet according to one embodiment of the present invention includes a steel sheet and an insulation coating, in which the insulation coating contains a first metal phosphate, which is a metal phosphate of one or two more metals selected from Al, Fe, Mg, Mn, Ni, and Zn; a second metal phosphate, which is a metal phosphate of one or two more metals selected from Co, Mo, V, W, and Zr; and colloidal silica, the insulation coating does not contain chromate, and an elution amount of phosphoric acid of the insulation coating as determined by boiling the grain-oriented electrical steel sheet in a boiled pure water for 10 minutes, then measuring an elution amount of phosphoric acid into the pure water, and dividing the amount of phosphoric acid by the area of the insulation coating of the boiled grain-oriented electrical steel sheet is 30 mg/m.sup.2 or less.

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 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, the surface of the base steel sheet has an etch pit structure, an average thickness of the intermediate layer is 0.2 to 10.0 ?m, an average thickness of the insulating coating is 2.0 to 10.0 ?m, 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; and an insulating coating formed on a surface of the base steel sheet, in which 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 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 %.

A grain-oriented electrical steel sheet has magnetic properties improved over conventional grain-oriented electrical steel sheets. A method of producing a grain-oriented electrical steel sheet comprises: heating a steel slab at 1300? C. or less, the steel slab having a chemical composition containing C, Si, Mn, acid-soluble Al, S and/or Se, Sn and/or Sb, N, and a balance being Fe and inevitable impurities; subjecting the steel slab to hot rolling to obtain a hot rolled steel sheet; subjecting the hot rolled steel sheet to cold rolling once, or twice or more with intermediate annealing performed therebetween, to obtain a cold rolled steel sheet with a final sheet thickness; subjecting the cold rolled steel sheet to primary recrystallization annealing; applying an annealing separator to a surface of the cold rolled steel sheet after the primary recrystallization annealing; and then subjecting the cold rolled steel sheet to secondary recrystallization annealing.

The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380? C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?.sub.t of 0.50 or more and to finish rolling with a rolling finish temperature of 900? C. or higher to obtain a hot-rolled sheet, cooling the hot-rolled sheet for 1 second or longer at a cooling rate of 70? C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600? C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.

Provided is a grain-oriented electrical steel sheet that achieves both low iron loss and low magnetostriction and has excellent transformer properties. The grain-oriented electrical steel sheet has a thermal strain-imparted region extending linearly in a direction crossing the rolling direction, and in the strain distribution in the rolling direction of the thermal strain-imparted region, the strain at both ends of the thermal strain-imparted region is tensile strain larger than the strain at the center of the thermal strain-imparted region.

This grain-oriented electrical steel sheet includes a base steel sheet, a forsterite-based primary film disposed on a surface of the base steel sheet, and a phosphate-based tension-imparting film containing no chromium, which is disposed on a surface of the primary film. In a case where a Ti content and a S content are respectively expressed as XTi and XS, by mass %, the forsterite-based primary film satisfies Expression (1) and Expression (2). A strain-introduced magnetic domain control is performed on the grain-oriented electrical steel sheet
0.10?XTi/XS?10.00Expression (1)
XTi+XS?0.10 mass %.Expression (2)

The present invention relates to an annealing separator for an oriented electrical steel sheet, an oriented electrical steel sheet, and a manufacturing method of an oriented electrical steel sheet.

An annealing separator for an oriented electrical steel sheet including: a first component including a Mg oxide or a Mg hydroxide; and a second component including one kind among oxides and hydroxides of a metal selected from Al, Ti, Cu, Cr, Ni, Ca, Zn, Na, K, Mo, In, Sb, Ba, Bi, and Mn, or two or more kinds thereof, and of which Equation 1 below is satisfied, an oriented electrical steel sheet manufactured by using the same, and a manufacture method of an oriented electrical steel sheet, are provided.

0.05<[A]/[B]<10.5[Equation 1]

(In Equation 1, [A] is a content of the second component with respect to a total amount (100 wt %) of the annealing separator, and [B] is a content of the first component with respect to a total amount (100 wt %) of the annealing separator).

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).