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 the insulation coating has a crystalline phosphide-containing layer containing a crystalline phosphide in an area in contact with the intermediate layer when viewing a cross section whose cutting direction is parallel to a thickness direction.

Proposed is a non-oriented electrical steel sheet being low in iron loss and excellent in tensile strength and fatigue strength, which has a chemical composition comprising C: not more than 0.005 mass %, Si: 3 to 5 mass %, Mn: not more than 5 mass %, P: not more than 0.1 mass %, S: not more than 0.01 mass %, Al: not more than 3 mass %, N: not more than 0.005 mass %, Zn: 0.0005 mass % to 0.003 mass %, and the remainder being Fe and inevitable impurities, an average crystal grain size being not more than 40 μm, the number of the inclusions having a diameter of not less than 5 μm being not more than 5/mm.sup.2, a tensile strength being not less than 600 MPa, and the fatigue strength being not less than 450 MPa.

A non-oriented electrical steel sheet according to one embodiment of the present invention comprises: 1.5 to 4.0 wt % of Si; 0.1 to 1.5 wt % of Mn, 0.7 to 1.5 wt % of Al; 0.0001-0.003 wt % of Bi; and 0.0001 to 0.003 wt % of Ga, with the balance comprising Fe and inevitable impurities, and satisfies the following Formula 1.

[Al]+[Mn]≥0.87  [Formula 1]

(here, [Al] and [Mn] represent the contents (wt %) of Al and Mn, respectively.)

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.

A non-oriented electrical steel sheet according to one embodiment of the present invention comprises, by weight %, 1.5 to 4.0% of Si, 0.7 to 2.5% of Al, 1 to 2% of Mn, 0.003 to 0.02% of Cu, at most 0.005% of S (not 0%), and the remainder comprising Fe and unavoidable impurities, and satisfies formulas 1 and 2 below.

150≤[Mn]/[Cu]≤250  [Formula 1]

3≤[Cu]/[S]≤7  [Formula 2]

(here, [Mn], [Cu], and [S] represent Mn, Cu, and S contents (weight %), respectively.)

A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when (α.sub.1 β.sub.1 γ.sub.1) and (α.sub.2 β.sub.2 γ.sub.2) represent deviation angles of crystal orientations measured at two measurement points which are adjacent on the sheet surface and which have an interval of 1 mm, the boundary condition BA is defined as [(α.sub.2−α.sub.1).sup.2+(β.sub.2−β.sub.1).sup.2+(γ.sub.2−γ.sub.1).sup.2].sup.1/2≥0.5°, and the boundary condition BB is defined as [(α.sub.2−α.sub.2).sup.2+(β.sub.2−β.sub.1).sup.2+(γ.sub.2−γ.sub.1).sup.2].sup.1/2≥2.0°, the boundary which satisfies the boundary condition BA and which does not satisfy the boundary condition BB is included.

A grain-oriented electrical steel sheet according to an embodiment of the present invention includes: in wt %, Si at 1.0 to 7.0%, Mn at 0.5% or less (excluding 0%), Al at 0.005% or less (excluding 0%), S at 0.0055% or less (excluding 0%), one or more of Ba and Y at 0.005 to 0.5%, one or more of Sn at 0.02 to 0.15%, Sb at 0.01 to 0.08%, and Ni at 0.02 to 0.5%, and the balance of Fe and inevitable impurities.

A non-oriented electrical steel sheet is provided which has a chemical composition that contains, in mass%, C: 0.0050% or less, Si: 0.10 to 1.50%, Mn: 0.10 to 1.50%, sol. Al: 0.0050% or less, N: 0.0030% or less, S: 0.0040% or less, and O: 0.0050 to 0.0200%, and contains one or more elements selected from a group of La, Ce, Zr, Mg and Ca in a total amount of 0.0005 to 0.0200%, with the balance being Fe and impurities. A number density N of suitable oxide particles is 3.0×10.sup.3 to 10×10.sup.3 particles/cm.sup.2, and a number density n of oxide particles containing La and the like satisfies the expression n/N≥0.01.

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.

Disclosed is a high-magnetic-induction oriented silicon steel, wherein the chemical elements thereof are, in mass percentage: Si: 2.0-4.0%; C: 0.03-0.07%; Al: 0.015-0.035%; N: 0.003-0.010%; Nb: 0.0010-0.0500%, the balance being Fe and inevitable impurities. The manufacturing method for the high-magnetic-induction oriented silicon steel includes the steps of: (1) smelting and casting; (2) heating a slab; (3) hot rolling; (4) cold rolling; (5) decarbonizing and annealing; (6) nitriding treatment; (7) applying an MgO coating; (8) high temperature annealing; and (9) applying an insulating coating; wherein a high-magnetic-induction oriented silicon steel is obtained by the manufacturing method, having an average primary grain size of 14-22 μm and a primary grain size variation coefficient of higher than 1.8; and wherein

[00001]$\mathrm{the}\mathrm{primary}\mathrm{grain}\mathrm{size}\mathrm{variation}\mathrm{coefficient}=\frac{\begin{array}{c}\mathrm{the}\mathrm{average}\mathrm{primary}\\ \mathrm{grain}\mathrm{size}\end{array}}{\begin{array}{c}\mathrm{standard}\mathrm{deviation}\mathrm{of}a\\ \mathrm{primary}\mathrm{grain}\mathrm{size}\end{array}}.$