Provided is a multilayer electrical steel sheet having low high-frequency iron loss and high magnetic flux density. The multilayer electrical steel sheet has an inner layer and surface layers provided on both sides of the inner layer, in which the surface layers and inner layer have predetermined chemical compositions, the multilayer electrical steel sheet having: ΔSi of 0.5 mass % or more, ΔSi being defined as a difference between a Si content in the surface layer [Si].sub.1 and a Si content in the inner layer [Si].sub.0 represented by [Si].sub.1−[Si].sub.0; Δλ.sub.1.0/400 of 1.0×10.sup.−6 or less, Δλ.sub.1.0/400 being defined as an absolute value of the difference between a magnetostriction of the surface layer λ.sub.1.0/400,1 and a magnetostriction of the inner layer λ.sub.1.0/400,0; a sheet thickness t of 0.03 mm to 0.3 mm, and a ratio of a total thickness of the surface layers t.sub.1 to t of from 0.10 to 0.70.

Provided are: a novel magnetic material having high magnetic stability, in particular, having an extremely high saturation magnetization; and a method for producing the same, wherein the magnetic material, due to having a higher saturation magnetization than ferrite magnetic materials and a higher electrical resistivity than existing metallic magnetic materials, resolves problems such as eddy current loss. According to the present invention, Co-ferrite nanoparticles obtained by wet synthesis are reduced in hydrogen and subjected to grain growth, and bcc- or fcc-(Fe, Co) phases and Co-enriched phases are nano-dispersed using phase separation via a disproportionation reaction to prepare a magnetic material powder. In addition, the magnetic material powder is sintered into a solid magnetic material.

A non oriented electrical steel sheet consists of a silicon steel sheet and an insulation coating. The silicon steel sheet contains Si, Al, and Mn as chemical composition, and an alignment degree to {5 5 7}<7 14 5> orientation in a central area along a thickness direction of the silicon steel sheet is 12 to 35.

Provided is a method of easily producing a non-oriented electrical steel sheet that contains substantially no Al and contains large amounts of Si and Mn and has low iron loss, comprising hot rolling a slab having a specified chemical composition to obtain a hot-rolled sheet; coiling the hot-rolled sheet; cold rolling the hot-rolled sheet once or twice with intermediate annealing being performed therebetween, to obtain a cold-rolled sheet; and subjecting the cold-rolled sheet to final annealing, wherein the hot-rolled sheet after the hot rolling is cooled at an average cooling rate from 800° C. to 650° C. of 30° C./s or more, and thereafter the coiling is performed at 650° C. or less.

According to an exemplary embodiment of the present invention, a manufacturing method of a grain-oriented electrical steel sheet, includes: preparing a slab; heating the slab; forming a hot-rolled sheet by hot-rolling the slab; performing hot-rolled sheet annealing on the hot-rolled sheet; forming a cold-rolled sheet by cold-rolling the hot-rolled sheet that has been completely subjected to the hot-rolled sheet annealing; performing first recrystallization annealing on the cold-rolled sheet; and performing second recrystallization annealing on the cold-rolled sheet that has been completely subjected to the first recrystallization annealing, wherein the hot-rolled sheet undergoes a first heating step, a second heating step, and a soaking step, and a temperature rise rate t.sub.1 of the first heating step and a temperature rise rate t.sub.2 of the second heating step satisfy Formula 1.
5×t.sub.2≤t.sub.1  [Formula 1]

A new and improved method for producing electrical steel sheet enabling production of electrical steel sheet excellent in magnetic characteristics and coating film adhesion, the method for producing electrical steel sheet containing a process of bringing an electrical steel sheet containing, by mass %, C: more than 0% and 0.10% or less, Si: 2.5% or more and 4.5% or less, Mn: 0.01% or more and 5.0% or less, a total of one or more of S, Se, and Te: more than 0% and 0.050% or less, acid soluble Al: more than 0% and 5.0% or less, N: more than 0% and 0.015% or less, and P: more than 0% and 1.0% or less and having a balance of Fe and impurities into contact with a solution, the solution containing one or more elements from among Cu, Hg, Ag, Pb, Cd, Co, Zn, and Ni, a total of concentrations of the elements being 0.00001% or more and 1.0000% or less.

Provided is a production method for a grain-oriented electrical steel sheet that is thin and has excellent magnetic characteristics. An embodiment of the present invention provides a production method that is for a grain-oriented electrical steel sheet and that comprises: a hot rolling step; an optional hot-rolled sheet-annealing step; an acid-washing step; a cold rolling step; a primary recrystallization-annealing step; a finishing-annealing step; and a planarization-annealing step. In the acid-washing step, an acid-washing solution containing 0.0001-5.00 g/L of Cu is used. The thickness of a cold-rolled steel sheet is 0.15-0.23 mm. The average temperature increase rate in the temperature range of 30-400° C. in a temperature increase process in the primary recrystallization step is more than 50° C./sec but not more than 1000° C./sec.

A new and improved method for producing grain-oriented electrical steel sheet enabling production of grain-oriented electrical steel sheet realizing high magnetic flux density and excellent in magnetic characteristics, that is, as one aspect, a method for producing grain-oriented electrical steel sheet comprising a hot rolling process, cold rolling process, primary recrystallization annealing process, finish annealing process, and flattening annealing process, wherein shot blasting treatment and/or leveling treatment and treatment for contact with a solution are performed, the solution contains Cu etc. in a predetermined amount, the pH is −1.5 or more and less than 7, a solution temperature is 15° C. or more and 100° C. or less, and the time during which the steel sheet is dipped in the solution is 5 seconds or more and 200 seconds or less.

Grain-oriented electrical steel sheet excellent in magnetic properties and excellent in adhesion of the primary coating to the steel sheet is provided. The grain-oriented electrical steel sheet according to the present invention is provided with a base metal steel sheet containing a chemical composition containing, by mass %, C: 0.005% or less, Si: 0.5 to 7.0%, Mn: 0.05 to 1.00%, a total of S and Se: 0.005% or less, sol. Al: 0.005% or less, and N: 0.005% or less and having a balance comprised of Fe and impurities and with a primary coating formed on a surface of the base metal steel sheet and containing Mg.sub.2SiO.sub.4as a main constituent, wherein a peak position of Al emission intensity obtained when performing elemental analysis by glow discharge optical emission spectrometry from a surface of the primary coating in a thickness direction of the grain-oriented electrical steel sheet is arranged within a range of 2.0 to 12.0 μm from the surface of the primary coating in the thickness direction, and a number density of Al oxides of a size of 0.1 μm or more in terms of a circle equivalent diameter based on the area at the peak position of Al emission intensity is 0.03 to 0.2/μm.sup.2.

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.