Disclosed is a non-oriented electrical steel sheet with low magnetic anisotropy, which comprises the following chemical elements in mass percentage: 0<C≤0.005%; Si: 2.0-3.5%; Mn: 0.1-2.0%; at least one of Sn and Sb: 0.003-0.2%; Al: 0.2-1.8%; the balance being Fe and inevitable impurities. Further disclosed is a manufacturing method for the above non-oriented electrical steel sheet with low magnetic anisotropy, which includes the following steps: (1) smelting and casting; (2) hot rolling; (3) normalizing; (4) cold rolling; (5) continuous annealing: rapidly heating a cold-rolled steel sheet from an initial temperature of 350° C.-750° C. to a soaking temperature at a heating rate of 50-800° C./s, and performing soaking and heat preservation; and (6) applying an insulating coating to obtain a finished non-oriented electrical steel sheet. The non-oriented electrical steel sheet is characterized by low iron loss and low magnetic anisotropy at high frequency.

Disclosed is a grain-oriented electrical steel sheet capable of obtaining excellent magnetic properties stably over the entire coil length. A grain-oriented electrical steel sheet includes: a chemical composition containing, in mass %, C: 0.005% or less, Si: 2.0% to 4.5%, and Mn: 0.01% to 0.5%, and, in mass ppm, N: 20 ppm or less, each of Se, Te, and O: less than 50 ppm, S: less than 30 ppm, and acid-soluble Al: less than 40 ppm, and Ti: less than 30 ppm, of which 5 ppm or more and 25 ppm or less is acid-soluble Ti, with the balance being Fe and inevitable impurities; and precipitates containing Ti and N with a grain size of 200 nm or more at a frequency of 0.05 grains/mm.sup.2 or more.

The present disclosure relates to a method for manufacturing a non-oriented electrical steel sheet and the manufactured non-oriented electrical steel sheet, the method including: heating a slab containing, by wt %, 0.005% or less of C, 2.5 to 4.0% or less of Si, 0.1% or less of P, 0.1 to 2.0% of Al, 0.2 to 2.5% of Mn, 0.003% or less of N, 0.005% or less of Ti and Nb, 0.003% or less of S, 0.005 to 0.025% of V, 0.1% or less of Cu, and a balance of Fe and inevitably mixed impurities, and satisfying the following Expression 1; hot-rolling the slab to manufacture a hot-rolled sheet; cold-rolling the hot-rolled sheet to manufacture a cold-rolled sheet; and performing final annealing on the cold-rolled sheet, wherein [Expression 1] is represented by (51*[C])/12−0.002≤[V]≤(51*[C])/12+0.004 (in Expression 1, [C] and [V] represent contents (wt %) of C and V, respectively).

A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when a grain size RAα.sub.L, a grain size RAβ.sub.L, and a grain size RAγ.sub.L are defined in a rolling direction L, the grain sizes satisfy RAβ.sub.L<RAα.sub.L and RAγ.sub.L<RAα.sub.L.

A grain-oriented electrical steel sheet has a base film composed mainly of forsterite on a surface of the grain-oriented electrical steel sheet and an insulating film containing mainly silicate-phosphate glass which is formed on a surface of the base film, in which, by controlling concentrations of Sr, Ca, and Ba in the base film and the insulating film to have specified gradients, the adhesion property and film tension of the insulating film are improved.

A chemical composition of a base metal of a non-oriented electrical steel sheet contains, by mass %, C: 0.0050% or less, Si: 3.8% to 5.0%, Mn: exceeding 0.2% and less than 2.0%, P: 0.030% or less, S: 0.0030% or less, Al: 0.005% or more and less than 0.050%, N: 0.0005% to 0.0030%, 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 0.10%, Sb: 0% to 0.10%, a remainder: Fe and impurities. [Si+0.5×Mn≥4.3] is satisfied and the average grain size of the base metal is in a range of 10 to 80 μm.

A non-oriented electrical steel sheet has a predetermined chemical composition. The chemical composition satisfies (2×[Mn]+2.5×[Ni]+[Cu])−([Si]+2×[sol.Al]+4×[P])≥1.50%. In a case where Ahkl-uvw represents the area ratio of crystal grains in an {hkl}<uvw> orientation to the entire visual field when a plane at a depth of ½ of a sheet thickness from a surface parallel to a rolled surface is measured by SEM-EBSD, A411-011 is 15.0% or more, and the average grain size is 50 μm to 150 μm.

A grain-oriented electrical steel sheet according to the present invention has a steel sheet surface provided with grooves and includes two or more broken lines including the grooves having a length of 5 to 10 mm on a straight line intersecting a rolling direction on the steel sheet surface. In each of the broken lines including the grooves, the grooves are arranged at equal intervals, and a ratio of the length of the groove to a length of a non-groove is in a range of 1:1 to 1.5:1.

Provided is 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 a chemical composition containing C: 0.0050% or less, Si: 2.0% or more and 6.0% or less, Mn: 1.0% or more and 3.0% or less, P: 0.20% or less, S: 0.0050% or less, N: 0.0050% or less, Al: 0.0050% or less, and one or more selected from B: 0.0001% or more and 0.0050% or less, Nb: 0.0001% or more and 0.0050% or less, and V: 0.0005% or more and 0.0500% or less, with a balance consisting of Fe and inevitable impurities, wherein a number density of Si—Mn nitrides with an average diameter of 50 nm or more and 500 nm or less is 1 or less per μm.sup.3.

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.