A non-oriented electrical steel sheet including a base metal that has a chemical composition including, in mass%, C: 0.0010 to 0.0040%, Si: 4.0 to 5.0%, Mn: 0.20% or less Al: 0.010% or more and less than 0.050%, P: 0.030% or less, S: 0.0030% or less, N: 0.0005 to 0.0030%, O: 0.0100 to 0.0400%, Ca: less than 0.0010%, Ti: less than 0.0050%, Nb: less than 0.0050%, Zr: less than 0.0050%, V: less than 0.0050%, Cu: less than 0.20%, Ni: less than 0.50%, Sn: 0 to 0.05%, Sb: 0 to 0.05%, and a balance: Fe and impurities, in which the base metal has an O content of less than 0.0050% in a region excluding a portion from a surface of the base metal to a position of 10 .Math.m in a depth direction of the base metal.

A reactor 1 of the present invention includes a coil 2 and a magnetic core 3 disposed inside and outside the coil 2 to form a closed magnetic path. At least part of the magnetic core 3 is made of a composite material containing a magnetic substance powder made of an identical material and a resin containing the powder being dispersed therein. In the particle size distribution of the magnetic substance powder, a plurality of peaks are present. That is, the magnetic substance powder contains both a fine powder and a coarse powder at high frequencies. Since the composite material contains the fine powder, it can reduce the eddy current loss, and hence achieves to be a low-loss material. Thanks to the mixed powder including the fine powder and the coarse powder, the packing density of the magnetic substance powder is increased. Thus, the composite material exhibits a high saturation magnetic flux density. By employing such a mixed powder, the raw material powder can be handled with ease, and excellent manufacturability of the composite material is obtained.

The present invention is directed at a method of production gain oriented Fe—Si steel sheet presenting an induction value at 800 A/m above 1.870 Tesla and a core power loss lower than 1.3 W/kg at a specific magnetic induction of 1.7 Tesla (T). The steel chemical composition comprises, in weight percentage: 2.8≦Si≦4, 0.20≦Cu≦0.6, 0.05≦Mn≦0.4, 0.001≦Al≦0.04, 0.025≦C≦0.05, 0.005≦N≦0.02, 0.005≦Sn≦0.03, S≦0.015 and optionally Ti, Nb, V or B in a cumulated amount below 0.02, the following relationships being respected: Mn/Sn≦40, 2.0≦C/N≦5.0, Al/N≦1.20, and the balance being Fe and other inevitable impurities.

A method for manufacturing a grain-oriented electrical steel sheet includes: a silicon steel material production process of producing a silicon steel material; a hot rolling process of obtaining a hot rolled sheet by subjecting the silicon steel material to hot rolling; a cold rolling process of obtaining a steel sheet having a final sheet thickness by subjecting the hot rolled sheet to a single cold rolling process or to multiple cold rolling processes having intermediate annealing performed between cold rolling processes; a decarburization annealing process of subjecting the steel sheet to decarburization annealing using a decarburization annealing furnace including a heating area and a soaking area; and a final annealing process of applying an annealing separator having alumina as a main component to the steel sheet and subjecting the steel sheet to final annealing, wherein, in the decarburization annealing process, when X represents the Cr content of the silicon steel material in terms of mass %, an oxidation degree P1 of an atmosphere gas in the heating area satisfies the following Expression 1 and an oxidation degree P2 of an atmosphere gas in the soaking area satisfies the following Expression 2:

0.18X−0.008≤P1≤0.25X+0.15≤0.20  (Expression 1); and

0.01≤P2≤0.15  (Expression 2).

[Problem] To provide: a coating liquid for forming an insulation coating for grain-oriented electrical steel sheets, which enables the achievement of excellent coating properties including high coating tension and excellent corrosion resistance even without using a chromium compound; a grain-oriented electrical steel sheet; and a method for producing a grain-oriented electrical steel sheet. [Solution] A coating liquid for forming an insulation coating for grain-oriented electrical steel sheets, which contains boric acid and hydrated silicate particles containing aluminum.

Provided are coated metal, the metal having improved properties due to a novel coating, a coating-forming treatment solution for forming the novel coating, and a method for producing the coated metal that has the novel coating. The coated metal includes metal and a coating formed on the metal. The coating includes Si, P, and O, and at least one selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, and Mn. The coating includes a compound having a NASICON-type crystal structure represented by the general formula M.sup.IM.sup.IV.sub.2(M.sup.VO.sub.4).sub.3.

A method for producing a grain oriented electrical steel sheet includes a decarburization annealing process where an oxidation degree PH.sub.2O/PH.sub.2 is controlled, an annealing separator applying process where a mass ratio of MgO and Al.sub.2O.sub.3 in an annealing separator is controlled, a final annealing process where an oxidation degree is controlled when atmosphere includes hydrogen or a dew point is controlled when atmosphere consists of inert gas, and an insulation coating forming process where a baking temperature and a heat treatment temperature are controlled.

Sheet or strip of cold-rolled and annealed ferrous alloy (1), characterized in that its composition is, in weight percentages: traces≤Co≤40%; if Co≥35%, traces≤Si≤1.0%; if traces≤Co<35%, traces≤Si≤3.5%; if traces≤Co<35%, Si+0.6% Al≤4.5−0.1% Co; traces≤Cr<10%; traces≤V+W+Mo+Ni≤4%; traces≤Mn≤4%; traces Al≤3%; traces≤S≤0.005%; traces≤P≤0.007%; traces≤Ni≤3%; traces≤Cu≤0.5%; traces≤Nb≤0.1%; traces≤Zr≤0.1%; traces≤Ti≤0.2%; traces≤N≤0.01%; traces≤Ca≤0.01%; traces≤Mg≤0.01%; traces≤Ta≤0.01%; traces≤B≤0.005%; traces≤O≤0.01%; the remainder being iron and impurities resulting from the preparation, in that, for an induction of 1.8 T, the maximum difference (Max Δλ) between the magnetostriction deformation amplitudes λ, measured parallel to the magnetic field (Ha) applied (λ/H) and perpendicular to the magnetic field (Ha) applied (λ.sup.⊥H) on three rectangular samples (2, 3, 4) of the said sheet or strip whose long sides are respectively parallel to the direction of rolling (DL) of the said sheet or strip, parallel to the transverse direction (DT) of the said sheet or strip, and parallel to the direction forming an angle of 45° with the said rolling direction (DL) and the said transverse direction (DT), being at most 25 ppm, and in that its recrystallization rate is 80 to 100%. Method of manufacturing such a sheet or strip, transformer magnetic core made from it and a transformer comprising it.

A manufacturing method of an electrical steel sheet according to an embodiment of the present invention includes: hot-rolling a slab to manufacture a hot-rolled sheet; removing some of scales formed on the hot-rolled sheet and leaving a scale layer having a thickness of 10 nm or more; controlling roughness of the hot-rolled sheet in which the scale layer remains; cold-rolling it to manufacture a cold-rolled sheet; and annealing the cold-rolled sheet.

A grain-oriented electrical steel sheet includes: a steel sheet; and an amorphous oxide layer that is formed on the steel sheet, in which a glossiness of a surface is 150% or higher.