The purpose of the present invention is to provide a method for manufacturing a grain-oriented electrical steel sheet, whereby it becomes possible to manufacture a grain-oriented electrical steel sheet having further improved iron loss properties stably. (Solution) According to one aspect of the present invention, a method for manufacturing a grain-oriented electrical steel sheet is provided, the method being characterized by comprising a re-heating step, a hot rolling step, a hot-rolled sheet annealing step, a cold rolling step, a decarburization annealing step and a final annealing step, wherein the decarburization annealing step includes a heating step of heating a cold-rolled sheet from an inlet side temperature T0° C. to a soaking temperature T2° C. and a soaking step of keeping the temperature of the cold-rolled sheet at the soaking temperature T2° C., and the heating rate HR1 from the time point when the temperature of the cold-rolled sheet is an inlet side temperature T0° C. to the time point when the temperature of the cold-rolled sheet reaches a attained temperature T1° C. is 40° C./sec or more and the heating rate HR2 from the time point when the temperature of the cold-rolled sheet is the desired temperature T1° C. to the time point when the temperature of the cold-rolled sheet reaches the soaking temperature T2° C. is more than 15° C./sec to 30° C./sec in the heating in the decarburization annealing step.

A grain oriented electrical steel sheet includes a base steel sheet, a glass film, and a tension-insulation coating. When a glow discharge emission spectroscopy is conducted from a surface of the glass film toward a depth direction, an analysis starting time Ts, a time T.sup.Al.sub.p at which Al shows a maximum emission intensity, an Al emission intensity F(T.sup.Al.sub.p) at the T.sup.Al.sub.p, a time T.sup.Si.sub.p at which Si shows a maximum emission intensity, and an Al emission intensity F(T.sup.Si.sub.p) at the T.sup.Si.sub.p satisfy 0.05≤F(T.sup.Si.sub.p)/F(T.sup.Al.sub.p)≤0.50 and 2.0≤(T.sup.Al.sub.p−Ts)/(T.sup.Si.sub.p−Ts)≤5.0.

[Problem] To provide a grain-oriented electrical steel sheet which is further improved in terms of iron loss before magnetic domain control, while achieving a sufficient iron loss improvement effect even in the control of a heat-resistant magnetic domain where a sufficient iron loss improvement effect has not been achieved. [Solution] A grain-oriented electrical steel sheet according to one aspect of the present invention comprises abase steel sheet and a glass coating that is formed on the surface of the base steel sheet, and is characterized in that: the base steel sheet contains as chemical components, in mass %, 0.010% or less of C, from 2.00% to 4.00% of Si, from 0.05% to 1.00% of Mn, from 0.010% to 0.065% of Al, 0.004% or less of N and 0.010% or less of S, with the balance being made up of Fe and impurities; the oxygen concentration in the glass coating and the base steel sheet is 2,500 ppm or less; and if I.sub.Al_1 is the first peak intensity of Al and I.sub.Al_2 is the second peak intensity of Al in the concentration profile of Al, the relationship of mathematical formula (1) is satisfied.

I.sub.Al_1<I.sub.Al_2   Formula (1):

Disclosed is a manufacturing method for a high silicon grain oriented electrical steel sheet, the silicon content of the high silicon grain oriented electrical steel is greater than 4 wt %, comprising the steps of: (1) performing decarburization annealing of a cold-rolled steel plate; (2) allowing high silicon alloy particles in a completely solid state to collide at a high speed with the surface of the decarburization annealed steel plate to be sprayed, thus forming a high silicon alloy coating on the surface of the steel plate to be sprayed; (3) coating a release agent and drying; and (4) annealing. The manufacturing method for the high silicon grain oriented electrical steel sheet of the present invention is inexpensive, and, the high silicon grain oriented electrical steel sheet produced is of stable quality and is provided with great magnetic performance.

A grain-oriented electrical steel sheet includes: a silicon steel sheet including Si and Mn; a glass film arranged on a surface of the silicon steel sheet; and an insulation coating arranged on a surface of the glass film, wherein the glass film includes a Mn-containing oxide.

A method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention comprises: a step for hot-rolling a slab to produce a hot-rolled sheet; a step for cold-rolling the hot-rolled sheet to produce a cold-rolled sheet; a step for subjecting the cold-rolled sheet to primary recrystallization annealing; and a step for subjecting the primary recrystallization annealing-completed cold-rolled sheet to secondary recrystallization annealing, wherein the primary recrystallization annealing step includes a preceding step and a subsequent step, and the amount (A) of nitriding gas introduced in the preceding step with respect to the total amount (B) of nitriding gas introduced in the primary recrystallization annealing step satisfies expression 1 below.
0.05≤[A]/[B]≤[t]  [Expression 1] (In expression 1, the amount of nitriding gas introduced is in units of Nm.sup.3/hr, and [t] represents the thickness (mm) of a cold-rolled sheet.)

An oriented silicon steel product with a low iron loss for a low-noise transformer, and manufacturing method thereof are provided. The oriented silicon steel product comprises: a silicon steel substrate, a magnesium silicate bottom layer formed on a surface of the silicon steel substrate, and an insulation coating applied on the magnesium silicate bottom layer. The magnesium silicate bottom layer has a visible light normal reflectivity (R) of 40-60% for. By strictly controlling the visible light normal reflectivity of the magnesium silicate bottom layer of the silicon steel substrate and the evenness of the gloss of magnesium silicate bottom layer, lower iron loss, and reduced magnetostriction can be achieved, and thus a silicon steel product with low noise and particularly suitable for transformers can be obtained.

A non-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes, by weight, Si: 2.0 to 3.5%, Al: 0.3 to 2.5%, Mn: 0.3 to 3.5%, Sn: 0.0030 to 0.2%, Sb: 0.0030 to 0.15%, P: 0.0040 to 0.18%, individually or in a total amount of 0.0005 to 0.03% of at least one of Ga and Ge, and a remainder including Fe and unavoidable impurities, and satisfies Equation 1 below.
0.05≤([Sn]+[Sb])/[P]≤25  [Equation 1] ([Sn], [Sb], and [P] respectively represent the content (% by weight) of Sn, Sb, and P.)

A heat-resistant magnetic domain refined grain-oriented silicon steel, a single-sided surface or a double-sided surface of which has several parallel grooves which are formed in a grooving manner, each groove extends in the width direction of the heat-resistant magnetic domain refined grain-oriented silicon steel, and the several parallel grooves are uniformly distributed along the rolling direction of the heat-resistant magnetic domain refined grain-oriented silicon steel. Each groove which extends in the width direction of the heat-resistant magnetic domain refined grain-oriented silicon steel is formed by splicing several sub-grooves which extend in the width direction of the heat-resistant magnetic domain refined grain-oriented silicon steel. The manufacturing method for a heat-resistant magnetic domain refined grain-oriented silicon steel comprises the step of: forming grooves on a single-sided surface or a double-sided surface of a heat-resistant magnetic domain refined grain-oriented silicon steel in a laser grooving manner, a laser beam of the laser grooving is divided into several sub-beams by a beam splitter, and the several sub-beams form the several sub-grooves which are spliced into the same groove.

A non-oriented electrical steel sheet with an average magnetostriction λ.sub.p-p at 400 Hz and 1.0 T of not more than 4.5×10.sup.−6, and area ratio of recrystallized grains at a section in rolling direction of steel sheet of 40 to 95% and an average grain size of 10 to 40 μm is obtained by subjecting a steel slab containing, in mass %, C: not more than 0.005%, Si: 2.8 to 6.5%, Mn: 0.05 to 2.0%, Al: not more than 3.0%, P: not more than 0.20%, S: not more than 0.005%, N: not more than 0.005%, Ti: not more than 0.003%, V: not more than 0.005% and Nb: not more than 0.005% and satisfying Si-2Al-Mn≥0 to hot rolling, hot-band annealing, cold rolling and finish annealing under adequate cold rolling and finish annealing conditions, and a motor core is manufactured by such a steel sheet.