Provided is a method of manufacturing a grain-oriented electrical steel sheet that has a uniform texture all along the longitudinal direction and has small fluctuations in magnetic properties. The method includes subjecting a predetermined hot-rolled and annealed sheet to cold rolling, where at least one time of cold rolling has a total rolling reduction of 80 % or more and is performed by a tandem mill, rolling performed in at least one stand of the tandem mill is performed under conditions of a rolling reduction of 30 % or more and a biting temperature To °C of a work roll of the stand, and a temperature at which either or both of a leading end and a tail end of the hot-rolled and annealed sheet are bitten by the work roll is 70° C. or higher and at least 10° C. higher than the temperature To °C.

Provided is a method of manufacturing a grain-oriented electrical steel sheet with which a grain-oriented electrical steel sheet with excellent magnetic properties and little variation in iron loss in the longitudinal direction of a coil can be stably manufactured. The method includes subjecting a steel slab to hot-rolling and optionally to annealing, then performing cold rolling once or twice or more to obtain a cold-rolled sheet with a final sheet thickness, and then subjecting the cold-rolled sheet to decarburization annealing and then secondary recrystallization annealing, where immediately before final cold rolling, a steel sheet is heated at a heating rate of 100° C./s or more to a heating temperature of 100° C. or higher and 350° C. or lower, and a time from when the steel sheet reaches the heating temperature to when it is bitten in a first pass of final cold rolling is set to within 5 seconds.

Provided is a production method for a grain-oriented electrical steel sheet with which stable magnetic properties are obtained in the same coil. The method comprises: hot rolling a steel slab having a predetermined chemical composition, followed by annealing to obtain a hot-rolled and annealed sheet; cold rolling the hot-rolled and annealed sheet one time, or two times or more with intermediate annealing being performed therebetween, to obtain a cold-rolled sheet, followed by subjecting to primary and secondary recrystallization annealing, wherein in the cold rolling, a rolling reduction ratio is 80% or more at least one time out of the one time or two times or more, and a steel sheet temperature T.sub.0 (° C.) while a rolling rate is a set value R.sub.0 (mpm) and a steel sheet temperature T.sub.1 (° C.) while the rolling rate is less than or equal to 0.5×R.sub.0 (mpm) satisfy a formula (1).

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.

In the production of a grain-oriented electrical steel sheet by hot rolling a slab containing Si: 2.0-8.0 mass % and no inhibitor-forming ingredients, cold rolling, subjecting to a decarburization annealing, applying an annealing separator composed mainly of MgO and containing a Ti compound(s) and subjecting to a finish annealing, an atmosphere in the heating process of the decarburization annealing is rendered into a dry atmosphere having a dew point of not higher than 0° C. and a Ti amount (Ti(a)) and a N amount (N(a)) contained in an iron matrix after the removal of a forsterite coating and a Ti amount (Ti(b)) and a N amount (N(b)) contained in the steel sheet having a forsterite coating are made to satisfy relationships as N(b)≤0.0050 mass %, N(b)/N(a)≥4, and Ti(b)/Ti(a)≥4.

A grain-oriented electrical steel sheet includes: a base steel sheet; an intermediate layer arranged in contact with the base steel sheet; and an insulation coating arranged in contact with the intermediate layer to be an outermost surface, in which a Cr content of the insulation coating is 0.1 at % or more on average, and when viewing a cross section whose cutting direction is parallel to a thickness direction, the insulation coating has a compound layer containing a crystalline phosphide in an area in contact with the intermediate layer.

Embodiments of the present invention comprise; annealing steel sheets (e.g., hot rolled steel sheets or thin cast strip steel); cold rolling the sheets in one or more cold rolling steps (e.g., with annealing steps between multiple cold rolling steps); and performing one or more of tension leveling, a rough rolling, or a coating process on the sheets after cold rolling, without an intermediate annealing step between the final cold rolling step and the tension leveling, the rough rolling, or the coating process, or the customer stamping or final customer annealing. In order to achieve the desired properties for the steel sheet, stamping and final annealing is performed by the customer. The new process provides an electrical steel with the similar, same, or better magnetic properties than an electrical steel manufactured using the traditional processing that utilizes an intermediate annealing step after cold rolling and before the stamping and final annealing.

Embodiments of the present invention comprise; annealing steel sheets (e.g., hot rolled steel sheets or thin cast strip steel); cold rolling the sheets in one or more cold rolling steps (e.g., with annealing steps between multiple cold rolling steps); and performing one or more of tension leveling, a rough rolling, or a coating process on the sheets after cold rolling, without an intermediate annealing step between the final cold rolling step and the tension leveling, the rough rolling, or the coating process, or the customer stamping or final customer annealing. In order to achieve the desired properties for the steel sheet, stamping and final annealing is performed by the customer. The new process provides an electrical steel with the similar, same, or better magnetic properties than an electrical steel manufactured using the traditional processing that utilizes an intermediate annealing step after cold rolling and before the stamping and final annealing.

To improve and stabilize magnetic properties, a steel sheet is soaked in a temperature range of 1000° C. or more and 1120° C. or less for 200 sec or less and then soaked in a temperature range of 650° C. or more and 1000° C. or less for 200 sec or less in annealing before final cold rolling, and the amount of Al in precipitates after the annealing before the final cold rolling is limited to 50% or more of the total amount of Al contained in the steel slab.

A grain-oriented electrical steel sheet according to an embodiment of the present invention includes: Si at 2.0 to 6.0 wt%, Mn at 0.12 to 1.0 wt%, Sb at 0.01 to 0.05 wt%, Sn at 0.03 to 0.08 wt%, Cr at 0.01 to 0.2 wt%, and the balance of Fe and inevitable impurities, and satisfies Formula 1 below.

4×[Cr]−0.1×[Mn]≥0.5×([Sn]+[Sb])   [Formula 1]

(In Formula 1, [Cr], [Mn], [Sn], and [Sb] represent contents (wt%) of Cr, Mn, Sn, and Sb, respectively.)