JPH07150310A - Non-oriented electrical steel sheet for high frequency - Google Patents

Abstract

PURPOSE:To develop an electrical steel sheet having small iron loss and high magnetic flux density in a high-frequency magnetized region by adjusting the composition, thickness of a non-oriented electrical steel sheet for high frequency and texture in the surface part of steel sheet. CONSTITUTION:A steel having a composition contg. by wt.%, <0.005% C, 1.0<Si<=2.0%, <0.004% or 0.1-0.5% Al, <0.005% N, or further 0.2-1.0% Mn, <0.2% P, <0.01% S is hot rolled, pickled and cold rolled and, after making it into a cold rolled sheet of 0.10-0.25mm thick, the final annealing is executed. The X-ray diffraction pattern of this cold rolled steel sheet is measured with an X-ray diffraction device, P value which is defined by the equation 1 is determined from X-ray integrated deflection strength l on each face of (211), (222), (321), (332), (200), (110) and (310) in the surface of sheet, further TP value is determined from this P value by the equation II and a structure contg. the texture whose TP value is <=1.5 of >=30% of the thickness in the thickness direction from each surface is made into. The electrical steel sheet having small iron loss and high magnetic flux density in the time of using in the high- frequency region of <=2000Hz is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency non-oriented electrical steel sheet, and more particularly to a high frequency non-oriented electrical steel sheet having a low iron loss and a high magnetic flux density.

[0002]

2. Description of the Related Art In recent years, there has been a demand for higher efficiency of electric equipment from the viewpoint of energy saving, and the electric equipment is often used in a high frequency range. Therefore, electromagnetic steel sheets used for iron cores of motors and the like are required to have excellent high-frequency magnetic characteristics.

However, when the electromagnetic steel sheet is magnetized in a high frequency range, iron loss rapidly increases due to an increase in eddy current loss. Therefore, attempts have been made to reduce the eddy current loss by reducing the thickness of the steel sheet and increasing the specific resistance of the steel sheet. That is, conventionally, for high-frequency applications, from the viewpoint of increasing the specific resistance, an electromagnetic steel sheet in which Si + Al is added in an amount of 1.7 to 6.5% by weight and a sheet thickness is 0.1 to 0.25 mm is used. ing.

For example, in JP-A-3-223445, the amount of Si + Al is set to 2.0 to 4.0% and the plate thickness is set to 0.1.
A high-frequency non-oriented electrical steel sheet having a size of ˜0.25 mm is disclosed.

[0005]

By the way, although the motors used in automobiles for NC machine tools and grinders are driven at high frequencies, the frequencies are 700 to 2000H.
It is about z. For magnetic steel sheets used for such applications, it is important not only to improve efficiency by reducing iron loss, but also to have high magnetic flux density from the viewpoint of high torque. For such applications, the above Si + Al is 1.7-6.
Although iron loss can be reduced by using a steel sheet containing about 5%, a decrease in magnetic flux density due to a decrease in saturation magnetic flux density is unavoidable, and the demand for higher torque due to higher magnetic flux density cannot be satisfied. There is no situation.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a high frequency non-oriented electrical steel sheet having a low iron loss and a high magnetic flux density in a high frequency magnetization region.

[0007]

[Means and Actions for Solving the Problems] In order not to reduce the magnetic flux density of the steel sheet, it is necessary to reduce the amounts of Si and Al in the steel sheet. However, the reduction of the amounts of Si and Al is naturally eddy current. This leads to an increase in total iron loss due to an increase in loss.
As a result of repeated studies by the inventors of the present application in order to achieve such conflicting characteristics, the following findings have been obtained.

When an electromagnetic steel sheet having a plate thickness of about 0.1 to 0.25 mm is magnetized at about 100 to 2000 Hz, the proportion of hysteresis loss in the total iron loss is about 30 to 70%. Therefore, in order to reduce the high frequency iron loss in a thin electromagnetic steel sheet having a plate thickness of about 0.1 to 0.25 mm, it is considered effective to reduce the hysteresis loss in addition to reducing the eddy current loss.

In order to reduce this hysteresis loss, attention was paid to the magnetic flux distribution in the plate thickness direction during high frequency magnetization. That is, when the steel sheet is magnetized at a high frequency, the distribution of the magnetic flux is not uniform in the thickness direction of the steel sheet but is concentrated on the surface layer portion due to the skin effect of the magnetic flux. Therefore, by controlling the texture of the steel sheet surface layer portion, not only the magnetic flux density can be improved, but also the hysteresis loss can be reduced. Due to such a hysteresis loss reduction effect,
In the thin electromagnetic steel sheet having a plate thickness of about 0.1 to 0.25 mm, it is possible to obtain an electromagnetic steel sheet having a low iron loss in a high frequency range even in an electromagnetic steel sheet having a lower Si and a lower Al than those of conventional components, and having a low Si, Improvement of saturation magnetic flux density due to low Al,
Not only the iron loss is low due to the formation of a specific texture,
It was found that the magnetic flux density was high. The present invention was made based on such findings of the inventors of the present application.

That is, in the present invention, in% by weight, C: 0.
005% or less, Si: more than 1.0% and 2.0% or less, A
1: 0.004% or less, or 0.1 to 0.5%, N: 0.
Including 005% or less, the plate thickness t is 0.10 to 0.25 mm
And (211), (222), (3
21), (332), (200), (110) and (3
10) Texture where the TP value represented by the following formula is 1.5 or less, where P (hkl) is the value of the ratio of the X-ray integrated reflection intensity to the theoretical intensity for each surface. And a non-oriented electrical steel sheet for high frequencies, which comprises 30% or more of the plate thickness from each surface in the plate thickness direction.

TP = [P (211) + P (222) + P (321) + P (332)] / [P (200) + P (110) + P (310)] Also, in% by weight, C: 0.005% Below, Si: 1.0
% To 2.0% or less, Mn: 0.2 to 1.0%, P:
0.2% or less, S: 0.01% or less, Al: 0.004
% Or less or 0.1 to 0.5%, N: 0.005% or less, the plate thickness t is 0.10 to 0.25 mm, and (211), (222) in the plate surface. (321), (33
2), (200), (110) and (310) planes, the value of the ratio of the X-ray integrated reflection intensity to the theoretical intensity is P (hkl), the TP value represented by the above formula The present invention provides a non-oriented electrical steel sheet for high frequencies, characterized in that it contains 30% or more of the sheet thickness from the surface in the sheet thickness direction from the surface so as to be 1.5 or less.

Furthermore, in any of the above-mentioned high frequency non-oriented electrical steel sheets, the average crystal grain size D in the steel sheet cross section is
It is intended to provide a non-oriented electrical steel sheet for high frequencies, characterized by satisfying 0.1t ≦ D ≦ 0.7t.

Furthermore, in any of the above-mentioned high frequency non-oriented electrical steel sheets, B ₁₀ ≧ 1.54T and W 15/400 ≦ 35 W / kg at a frequency of 100 to 2000 Hz. The present invention provides a magnetic electrical steel sheet.

The present invention will be described in detail below.
(1) Component The reasons for limiting each component are as follows. In the following, all percentages are by weight.

Si: Si is an element effective for increasing the specific resistance of the steel sheet, and in order to fully exhibit this effect in the frequency range assumed by the present invention, Si should be contained in excess of 1.0%. is necessary. On the other hand, the saturation magnetic flux density decreases with the addition of Si, and when it exceeds 2.0%, its value becomes lower than the allowable range. Therefore, the Si amount is 1.0
% To 2.0% or less.

Al: Al forms fine AlN when added in a trace amount and impairs magnetic properties. Therefore, the content of Al is limited to 0.004% or less. On the other hand, 0.1
When added in excess of%, AlN becomes coarse and does not deteriorate the magnetic properties and contributes to an increase in specific resistance.
If it is 0.5% or more, the magnetic flux density is lowered like Si. Therefore, the Al content is 0.004% or less or 0.1
To 0.5%.

C: Since C has a problem of magnetic aging, it is specified to 0.005% or less so that such a problem does not occur. N: N is 0.005% or more, the magnetic properties are deteriorated, so the content is defined as 0.005% or less.

The above are the important components in the present invention, but by defining Mn, S, and P shown below as follows, it is possible to obtain better characteristics. Mn: Mn is required to be 0.2% or more in order to prevent red hot embrittlement during hot rolling, but if it exceeds 1.0%, magnetic properties deteriorate. Therefore, the Mn amount is 0.2 to 1.0.
Specify in the range of%.

S: S forms MnS or the like that deteriorates the magnetic characteristics, so 0.01% is the upper limit at which S does not occur. P: P is an element necessary for improving the punchability of the steel sheet, but if it is added in an amount exceeding 0.2%, the magnetic flux density will decrease. Therefore, the P amount is set to 0.2% or less.

It should be noted that Sb, Sn, B, Cu and Zr may be added to improve the magnetic characteristics.
In addition, the amount of unavoidable impurity elements other than these elements is acceptable as long as it is contained in ordinary steel.

(2) Plate Thickness Next, the reason for limiting the plate thickness will be described. Reducing the plate thickness is very effective in reducing eddy current loss in the high frequency range. However, if the plate thickness is less than 0.10 mm, not only cold rolling becomes difficult, but also the number of laminated steel plates at the time of assembling the rotor and the stator of the motor increases, resulting in a decrease in production efficiency. Further, if it exceeds 0.25 mm, eddy current loss increases, which leads to increase in iron loss. Therefore, the plate thickness is set to 0.10 to 0.25 mm.

(3) Texture As for the texture of the steel plate surface, the X-ray diffraction pattern is measured based on the reflection method using an X-ray diffractometer after reducing the thickness of the steel plate to a target plate thickness, 211), (222), (32
1), (332), (200), (110) and (31
The P value defined by the following equation (1) is obtained from the X-ray integrated reflection intensity I of the (0) surface, and the TP value shown by the equation (2) is obtained from this P value, and the TP value is evaluated according to the magnitude. To do.

P (hkl) = 7 × [I / I ₀ (hkl)] / [ΣI / I ₀ (hkl)] I (hkl): X-ray integrated intensity in the (hkl) plane I ₀ (hkl): ( Theoretical strength in hkl plane ... (1) TP = [P (211) + P (222) + P (321) + P (332)] / [P (200) + P (110) + P (310)] .... (2) That is, (211), (222), (321), and (332) that do not include the <100> direction that is the easy axis of magnetization.
Including the sum of the P values of the faces and the <100> direction (200),
The lower the TP value, which is the ratio to the sum of the P values of the (110) and (310) planes, is, the better the texture formed in the magnetic properties of the steel sheet.

By the way, when the steel sheet is magnetized at a high frequency,
Due to the skin effect of the magnetic flux, the distribution of the magnetic flux is not uniform in the plate thickness direction of the steel sheet but is concentrated on the surface layer portion. For example, at 100 Hz, about 70% of the magnetic flux concentrates on the portion within 30% of the plate thickness from each surface. This tendency becomes remarkable as the frequency becomes higher. At 1000 Hz, 80 to 90% of the magnetic flux concentrates on the portion within 30% of the plate thickness from the surface. From this, it is understood that the magnetic flux density can be improved and the hysteresis loss can be efficiently reduced by forming a preferable texture in the surface layer portion of the steel sheet.

Here, the method for forming a desired texture is not particularly limited, but in the present invention, it is important to control the texture of the surface layer of the steel sheet. Therefore, after applying pressure to the hot rolled sheet, It is preferable to apply a method of performing hot-rolled sheet annealing. In this method, the depth of the desired texture of the steel sheet surface layer portion can be arbitrarily adjusted by adjusting the pressure regulation rate or the annealing temperature.

In the present invention, based on the above, it is a requirement that the texture having the TP value of 1.5 or less is contained in the plate thickness direction from each surface in an amount of 30% or more of the plate thickness. The reason will be described below.

FIG. 1 shows steel type A (C: 0.040%, S
i: 1.05%, Mn: 0.22%, P: 0.10%,
S: 0.004%, Al: tr, N: 0.0031
%), Steel type B (C: 0.031%, Si: 1.90%,
Mn: 0.60%, P: 0.03%, S: 0.004
%, Al: 0.40%, N: 0.0030%),
For hot rolled sheet pressure controlled-magnetic steel sheet produced using a normal process without annealing, and for hot rolled sheet pressure controlled-annealing conditions to control the texture of the electromagnetic steel sheet, the sheet thickness from the steel sheet surface it is a diagram showing the relation between TP value and the magnetic flux density B ₁₀ of definitive to 30% of the depth. In addition, the steel plate produced by the normal process using the steel type A and not performing hot rolling plate pressure control-annealing has a plate thickness t.
= 0.20 mm, average crystal grain size D = 50 μm, and the thickness of the hot-rolled plate under pressure-annealing was t = 0.20 m.
m, and the average crystal grain size D was 48 μm. The steel plate manufactured by the normal process using the steel type B has a plate thickness t = 0.20.
mm, the crystal grain size D = 60 μm, the thickness of the hot-rolled plate under pressure-annealing was t = 0.20 mm, and the crystal grain size D =
It was 56 μm. Here, the evaluation of the texture by the TP value at the depth of 30% of the plate thickness from the surface of the steel plate is
This is because at a frequency of 100 to 2000 Hz, 70 to 90% of the magnetic flux concentrates in a region within 30% of the plate thickness from the steel plate surface. In addition, the magnetic flux density was evaluated at B ₁₀ at frequency 1
This is because the exciting magnetic flux density of the equipment used at 00 to 2000 Hz is often a relatively high magnetic flux density of about 1.5 T even though it is a high frequency, and B ₁₀ is almost equivalent to that.

From FIG. 1, it is confirmed that when TP ≦ 1.5, the magnetic flux density is higher than that of the conventional material by 0.03 T or more, clearly improving the magnetic flux density. Next, the effect of frequency on the iron loss reduction effect by controlling the texture is shown. Here, the steel type C (C: 0.037
%, Si: 1.10%, Mn: 0.18%, P: 0.1
1%, S: 0.005%, Al: 0.30%, N: 0.
0035%), steel type D (C: 0.045%, Si: 1.
50%, Mn: 0.25%, P: 0.09%, S: 0.
004%, Al: 0.20%, N: 0.0030%), and an electrical steel sheet produced by a normal process in which hot rolled sheet pressure regulation-annealing is not performed, and hot rolled sheet pressure regulation-annealing conditions Value of the iron loss W15 at each frequency for the electrical steel sheet of the present invention in which a texture having a TP value of 1.5 or less is adjusted to include 30% or more of the sheet thickness in the sheet thickness direction from the surface layer. I asked. As for the material of the present invention, for steel type C, t =
0.2 mm, average crystal grain size D = 31 μm, TP ≦ 1.5
Area depth 0.082mm (x / t = 41%), Steel type D
For t = 0.1 mm, average crystal grain size D = 23 μ
m, TP ≦ 1.5 area depth 0.035 mm (x / t =
35%) was used. Further, as a conventional material, for steel type C, t = 0.2 mm, average crystal grain size D = 30 μ
TP = 2.m at a depth of 30% of the plate thickness from the steel plate surface.
7. For steel type D, t = 0.1 mm, average crystal grain size D
= 21 μm, T at a depth of 30% of the plate thickness from the steel plate surface
The one with P = 2.6 was used. FIG. 2 is a plot of the ratio of W15 of the present invention material to W15 of the conventional material versus frequency.

From this FIG. 2, frequencies 100-2000H
It can be seen that the effect of improving iron loss is large in the z range, but the effect of improving iron loss is relatively small below 100 Hz and above 2000 Hz. This is because the skin effect of the magnetic flux is small at less than 100 Hz, so the thickness of the surface layer is 3
Adjusting the texture of about 50% is less effective,
This is because when it exceeds 0 Hz, the proportion of the hysteresis loss in the total iron loss becomes small, and even if the hysteresis loss is reduced by adjusting the texture, the effect on the total iron loss is small. As can be seen from FIG. 2, in the frequency range of 100 to 2000 Hz, the value of the ratio of W15 of the present invention material to W15 of the conventional material is substantially constant, and the iron loss improving effect by adjusting the texture is It can be seen that the range does not depend on the frequency. From the above, it can be seen that the electromagnetic steel sheet of the present invention is preferably used at 100 to 2000 Hz.

FIG. 3 shows the above-mentioned steel type A (plate thickness t = 0.20).
mm, average crystal grain size D = 60 μm) and steel type E (C:
0.036%, Si: 1.40%, Mn: 0.17%,
P: 0.13%, S: 0.003%, Al: 0.40
%, N: 0.0040%, plate thickness t = 0.20 mm, average crystal grain size D = 41 μm), the depth from the steel plate surface in the region of TP ≦ 1.5, magnetic flux density B ₁₀ and iron loss W 15 / 100
It is a figure which shows the relationship with. Here, the depth of the region of TP ≦ 1.5 is obtained by measuring the texture of the plate surface by X-ray diffraction while decreasing the thickness from the steel plate surface in the plate thickness direction, and TP = 1.5.
Was used. Here, the frequency is 100H
Understanding the iron loss at z is based on the results shown in FIG.

From this FIG. 3, magnetic flux density B ₁₀ and iron loss W 15
It was confirmed that in all cases of / 100, the area of TP ≦ 1.5 rapidly increased up to 30% as it entered the surface of the steel sheet, and the area of TP ≦ 1.5 became deeper than that and did not change significantly. To be done. As mentioned above, this is 100Hz
The reason is that about 70% of the magnetic flux concentrates from the surface of the steel plate to the plate thickness portion. The skin effect of this magnetic flux density becomes more remarkable as the frequency becomes higher, and the magnetic flux concentrates on the surface layer more.
A value of 1.5 is sufficient.

From the above results, the present invention requires that a texture having a TP value of 1.5 or less is included in the plate thickness direction from each surface in an amount of 30% or more of the plate thickness. (4) Crystal grain size FIG. 4 is a diagram showing the influence on the iron loss W15 / 400 of the ratio D / t between the crystal grain size and the sheet thickness of the electromagnetic steel sheets produced by using the steel types B and C described above. is there. Here, the steel plate manufactured using the steel type B has a depth of 0.05 mm or more from the steel plate surface in the region of t = 0.15 mm, TP ≦ 1.5, and the steel plate manufactured using the steel type C has t = 0. The depth from the steel plate surface in the region of 2 mm and TP ≦ 1.5 was 0.07 mm or more.

As shown in FIG. 4, D / t is 0.1 to 0.1.
0.7 range, that is, the crystal grain size D is 0.1 t to 0.7
The iron loss is further reduced in the range of t. This is because when the crystal grain size D is in the range of 0.1t to 0.7t, a desired texture is moderately developed in the steel sheet surface layer portion, but it is desirable that the crystal grain size D is less than 0.1t. Even if the texture of is obtained, the hysteresis loss increases because the grain boundaries hinder the domain wall movement, and conversely, when the crystal grain size D exceeds 0.7 t, the hysteresis loss decreases but the eddy current loss increases. This is because iron loss increases.

From the above, the crystal grain size D is 0.1 t ≦
The range of D ≦ 0.7t is preferable. Next, a method for manufacturing the non-oriented electrical steel sheet of the present invention will be described. In the present invention, it is important to control the texture of the steel sheet surface layer portion, it is necessary to adjust the texture of the steel sheet surface layer portion by using an appropriate method, but there is no restriction on the method, Any method other than the above hot rolling pressure-annealing process can be used.

The other processes may be the same as those usually used. That is, regarding steelmaking, molten steel blown in a converter may be degassed to adjust it to a predetermined composition. Also, hot rolling may be performed under normal conditions. The cold rolling may be carried out once or may be carried out twice or more with intervening intermediate annealing, as long as the desired sheet thickness is finally obtained. Regarding the final annealing, normal annealing may be used, and by controlling the final annealing conditions, it becomes possible to obtain a desired crystal grain size.

For example, in the case of 1.4% Si-0.4% Al steel, the hot rolled sheet pressure control rate is 7.0%, the hot rolled sheet annealing condition is 850 ° C. × 3 hours, and the sheet is cold rolled. 0.2m thick
After setting m, the final texture can be obtained by performing the final annealing at 850 ° C. for 2 minutes. In the present invention, there is no problem in obtaining the texture of the present invention by adding Sb, Sn, B, Cu, Zr or the like.

[0037]

[Examples] Steel materials having compositions of steel types 1 to 13 shown in Table 1 were hot-rolled to a plate thickness of 2.0 mm, then pickled, and hot-rolled sheet pressure control conditions and hot-rolled sheet annealing shown in Table 2 were performed. Conditioning of hot-rolled sheet-
It was annealed. These steel plates are successively made into plate thicknesses of 0.1 to 0.
After cold rolling to 25 mm, final annealing was performed under the conditions shown in Table 2. The hot-rolled sheet annealing was performed in a 100% H ₂ atmosphere, and the final annealing was performed in a 25% H ₂ -75% N ₂ atmosphere.

Regarding the magnetic characteristics, ring test pieces having an outer diameter of 45 mm and an inner diameter of 33 mm were sampled from each steel sheet, the test pieces were measured at a frequency of 400 Hz, and further the crystal grain size was measured.

Steel plate thickness, average crystal grain size, TP ≦ 1.5
Table 3 shows the depth from the surface of the steel sheet and the magnetic characteristics in the region of. In Table 1, steel types 1 to 10 have compositions within the scope of the present invention, and steel types 11 to 13 have compositions outside the scope of the present invention. Further, the numbers 1 to 29 in Tables 2 and 3 indicate the numbers of the steel sheets produced by subjecting these steel types to hot rolling sheet pressure control-annealing under various conditions.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

Nos. 1, 2, 4, 7 to 9, 11, 13 satisfying the present invention are all steel compositions, plate thicknesses, and depths of regions having a texture such that the TP value is 1.5 or less. , 15
It was confirmed that each of No. 20 to No. 23 to No. 25 has low iron loss and high magnetic flux density in the high frequency region, and is excellent as a high frequency non-oriented electrical steel sheet.

On the other hand, the numbers 3, 5 in which at least one of the composition, the region depth of TP ≦ 1.5, and the plate thickness deviates,
It was confirmed that 10, 12, 14, 21, and 27 to 29 had high iron loss or low magnetic flux density.

[0045]

According to the present invention, by adjusting the composition, the plate thickness and the texture of the steel sheet surface layer portion, a high frequency non-oriented electrical steel having a low iron loss and a high magnetic flux density in the high frequency magnetized region is provided. To be done.

[Brief description of drawings]

FIG. 1 shows a steel sheet surface of an electromagnetic steel sheet manufactured by a normal process without hot-rolled sheet pressure control-annealing and a magnetic steel sheet with hot-rolled sheet pressure control-annealing condition adjusted to control texture. To TP value and magnetic flux density B ₁₀ at a depth of 30% of the plate thickness
FIG.

FIG. 2 is a diagram in which the ratio of W15 of the material of the present invention to W15 of the conventional material is plotted against frequency.

FIG. 3 is a diagram showing the relationship between the depth from the steel plate surface in the region of TP ≦ 1.5, the magnetic flux density B ₁₀ and the iron loss W 15/100.

[Fig. 4] Iron loss W15 of the ratio D / t of the crystal grain size of the steel plate to the plate thickness
Diagram showing the effect on / 400.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyoshi Okita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (4)

[Claims] 1. C, 0.005% or less by weight, S
i: 1.0% to 2.0% or less, Al: 0.004% or less, or 0.1 to 0.5%, N: 0.005% or less, and a plate thickness t of 0.10 to 0. 25 mm, and (211), (222), (321), (33) within the plate surface.
2), (200), (110), and (310) planes, the value of the ratio of the X-ray integrated reflection intensity to the theoretical intensity is P (hkl), TP represented by the following equation
A non-oriented electrical steel sheet for high frequencies, comprising a texture having a value of 1.5 or less in the sheet thickness direction from each surface in an amount of 30% or more of the sheet thickness. TP = [P (211) + P (222) + P (321) + P (332)] / [P (200) + P (110) + P (310)] 2. C: 0.005% or less by weight%, S
i: more than 1.0% and 2.0% or less, Mn: 0.2 to 1.0
%, P: 0.2% or less, S: 0.01% or less, Al:
0.004% or less or 0.1 to 0.5%, N: 0.00
5% or less, the plate thickness t is 0.10 to 0.25 mm, and (211), (222), (32) in the plate surface.
1), (332), (200), (110) and (31
When the value of the ratio of the X-ray integrated reflection intensity to the theoretical intensity of each of the 0) planes is P (hkl), the texture is such that the TP value represented by the following formula is 1.5 or less. A non-oriented electrical steel sheet for high frequencies, characterized by including from each surface in the sheet thickness direction 30% or more of the sheet thickness. TP = [P (211) + P (222) + P (321) + P (332)] / [P (200) + P (110) + P (310)] 3. The average crystal grain size D in the steel plate cross section is 0.1.
2. The condition t ≦ D ≦ 0.7t is satisfied.
Alternatively, the high-frequency non-oriented electrical steel sheet according to item 2. 4. At a frequency of 100 to 2000 Hz,
The non-oriented electrical steel sheet for high frequencies according to claim 1, wherein B ₁₀ ≧ 1.54T and W 15/400 ≦ 35 W / kg.