JP2004277760A - Non-oriented electromagnetic steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-oriented electromagnetic steel sheet which has adequate recyclability and has magnetic properties improved. <P>SOLUTION: The non-oriented electromagnetic steel sheet comprises, by mass%, 0.004% or less C, 0.7 to 1.5% Si, 0.1 to 0.3% Mn, less than 0.0005% sol. Al, 0.2% or less P, 0.005% or less S, 0.003% or less N, 0.1% or less Cr, 0.005% or less V, 0.001% or less Ti, 0.016 to 0.05% Cu and the balance Fe with unavoidable impurities. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００５３】
（実施例２）
鋼組成が本発明の範囲内にある鋼１スラブを用いて、熱間圧延や仕上げ焼鈍を種々の条件として厚さ０．５ｍｍの無方向性電磁鋼板を製造した。具体的には、スラブ加熱温度を１１００〜１２５０℃、熱延仕上げ温度を８００〜８８０℃、熱延鋼板の厚さを２．３ｍｍ、そして冷間圧延後の仕上げ焼鈍温度を７００〜９００℃とした。その製造された鋼板に分散する硫化物を抽出レプリカによりＴＥＭ観察し、１０個の微細硫化物（長径０．０５〜０．１μｍ）の組成をＥＤＳ分析し、平均のＣｕモル分率を求めた。また、磁性焼鈍後の磁気特性をエプスタイン法により測定した。表２に製造条件、Ｃｕモル分率、及び磁気特性を示す。図３に鉄損Ｗ_{１５ ／ ５０}と製造条件、Ｃｕモル分率の関係を示す。個々の製造条件と鉄損の間には明確な相関が認められないが、適正な製造条件の組み合わせで製造されたＮｏ．１、８、９の鋼板はＣｕモル分率が３０％以上となり、磁性焼鈍後の鉄損も３．７０Ｗ／ｋｇ以下で良好である。
【００５４】
【表２】

【００５５】
【発明の効果】
本発明の電磁鋼板は、このようにＡｌの含有量が極めて低いことから、リサイクル性にすぐれており、かつＳｉを０．７％以上含有させた場合でも、ＭｎおよびＣｕの含有量を所定の範囲とし、かつ窒化物生成元素であるＶ、Ｃｒ、Ａｌ、Ｔｉの含有量も十分に低減したものであるので、磁気特性に悪影響を与える窒化物を大幅に低減させることが可能となり、良好な磁気特性を有する電磁鋼板とすることができる。
【図面の簡単な説明】
【図１】鋼中におけるＣｕおよびＭｎの含有量と鉄損Ｗ_{１５ ／ ５０}との関係を示すグラフである。
【図２】鋼中に分散する介在物としての硫化物中のＣｕモル濃度と鉄損Ｗ_{１５ ／ ５０}との関係を示すグラフである。
【図３】（ａ）〜（ｃ）は鉄損Ｗ_{１５ ／ ５０}と各種製造条件との関係を示すグラフであり、（ｄ）は鋼中に分散する介在物としての硫化物中のＣｕモル分率と鉄損Ｗ_{１５ ／ ５０}との関係を示すグラフである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-oriented electrical steel sheet suitable for recycling. In particular, the present invention relates to a non-oriented electrical steel sheet suitable for use in magnetic annealing requiring grain growth in a relatively low temperature range.
[0002]
[Prior art]
In recent years, energy saving has become an important issue, and electric devices with higher efficiency than ever have been demanded. Therefore, there is a need for an electromagnetic steel sheet having higher magnetic properties than ever before. Furthermore, recently, due to environmental considerations, there is an urgent need to respond to recycling of iron core materials in electrical equipment.
[0003]
In order to increase the efficiency of electric equipment and reduce the size of the iron core material, it is effective to improve the magnetic properties of the magnetic steel sheet used as the material of the iron core. In the field of conventional non-oriented electrical steel sheets, the content of Si, Al, Mn, etc., in order to increase the specific resistance and reduce the eddy current loss, as a means of reducing iron loss among the magnetic properties, is particularly important. Enhancement techniques have been commonly used. Among them, Al is effective in improving the punching property of a steel sheet (suppressing die wear) because it hardly increases hardness in spite of a large effect of increasing specific resistance.
[0004]
However, Al-added steel leaves a problem in recyclability. That is, if Al contains a certain amount or more in steel, there is a problem that the electrode of the electric furnace is damaged when the iron core material is recycled or scrapped by a customer. Furthermore, when casting a motor shaft or the like using a recycled iron core, if 0.1% by mass or more of Al is contained, the surface oxidation of molten steel proceeds during casting, the viscosity increases, and There was also a problem that casting was hindered.
[0005]
Thus, when considering the recyclability, it is advantageous to reduce the Al. Accordingly, there is a demand for an electromagnetic steel sheet having a low Al content and high magnetic properties and a method for producing the same, and many have been proposed so far.
[0006]
For example, in Patent Document 1, Si: 0.1 to 1.0%, Mn ≦ 1.5%, sol. Al: An electromagnetic steel sheet with a low iron loss of 0.001 to 0.005% and an MnO concentration of 15% or less in inclusions has been proposed.
[0007]
In Patent Document 2, Si: 0.1 to 1.0%, Mn ≦ 1.5%, sol. Al: at 0.0005 to 0.001%, inclusions MnO concentration of 15% or less, low iron loss electrical steel sheet has been proposed is inclusions SiO ₂ concentration of 75% or more.
[0008]
Further, in Patent Document 3, Si: 0.05 to 1.0%, Mn: 0.25 to 0.5%, sol. An electrical steel sheet having Al ≦ 0.004% and a weight ratio of MnO to SiO ₂ in inclusions of MnO / SiO ₂ ≦ 0.3 has been proposed, and it is said that an electrical steel sheet having few scale defects and excellent surface properties can be obtained. .
[0009]
These techniques improve the magnetic properties by appropriately controlling the composition of the inclusions in addition to the steel material components, and indicate the appropriate ranges of the SiO ₂ concentration and the MnO concentration in the inclusions.
[0010]
However, in order to further improve the magnetic properties, the Si content is increased (for example, 0.7% by mass or more) to increase the specific resistance. Is deposited, which causes a problem that the magnetic characteristics are deteriorated. Therefore, the conventional technology has not been able to sufficiently respond to such a demand.
[0011]
[Patent Document 1]
JP-A-63-195217 [Patent Document 2]
JP-A-1-152239 [Patent Document 3]
JP-A-10-147849
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and proposes a non-oriented electrical steel sheet having good recyclability and improved magnetic properties.
[0013]
[Means for Solving the Problems]
Hereinafter, “%” indicating the content of each element in steel means “% by mass” unless otherwise specified.
[0014]
Generally, in order to simply improve the recyclability of the non-oriented electrical steel sheet, the Al content may be reduced to less than 0.1% to reduce the Al content. However, when the Al content is 0.005 to 0.1%, there is a problem that fine AlN precipitates to suppress crystal grain growth, so that magnetic properties are significantly deteriorated. From this point, the Al content is preferably less than 0.005%, whereby AlN precipitation is relatively suppressed.
[0015]
On the other hand, from the viewpoint of reducing the iron loss by increasing the specific resistance, it is preferable to increase the Si content. Deteriorates. Among the nitrides, SiMn-based nitrides, carbonitrides containing V and Cr, and Al nitrides are observed.
[0016]
Therefore, the inventors have conducted intensive studies to improve this point, and as a result, the C, N, and S contents are low, and the contents of V, Cr, Al, and Ti, which are nitride-forming elements, are sufficiently reduced. In addition, when the Mn content and the Cu content are combined and added in an appropriate range, and the composition of fine sulfides existing as inclusions is controlled as necessary, 0.7 to 1.5% of Si is contained. The knowledge that good iron loss characteristics can be obtained with a low Al material was obtained, and the present invention was completed based on this knowledge.
[0017]
That is, in the present invention, C: 0.004% or less, Si: 0.7 to 1.5%, Mn: 0.1 to 0.3%, sol. Al: less than 0.0005%, P: 0.2% or less, S: 0.005% or less, N: 0.003%, Cr: 0.1% or less, V: 0.005% or less, Ti: 0 The present invention provides a non-oriented electrical steel sheet containing 0.001% or less and Cu: 0.016 to 0.05%, with the balance being Fe and unavoidable impurities.
[0018]
Since the electrical steel sheet of the present invention has such an extremely low Al content, it is excellent in recyclability, and even when the Si content is in the above range, the contents of Mn and Cu are set in a predetermined range. In addition, since the contents of V, Cr, Al, and Ti, which are nitride-forming elements, are also sufficiently reduced, they have good magnetic properties.
[0019]
In the present invention, the Cu mole fraction (=% Cu / (% Cu +% Mn +% S) × 100) in the sulfide having a major axis of 0.05 to 0.1 μm existing as inclusions in the steel is 30%. It is preferable that it is above. This is because an electrical steel sheet having a sulfide having such a composition as an inclusion exhibits better magnetic properties.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
The inventors first conducted the following experiments to examine the effect of steel composition on magnetic properties.
[0021]
In mass%, C: 0.002%, Si: 0.8%, Mn: 0.08 to 0.5%, P: 0.05%, S: 0.0025 to 0.0032%, Cr: 0. 05%, V: 0.002%, Ti: 0.0003% or less, sol. A steel containing Al <0.0003%, N: 0.002% and the total amount of Cu changed in the range of 0.003 to 0.13% was melted in a laboratory to form an ingot and forged. And made it a slab.
[0022]
A slab having a thickness of 15 mm was cut out from the slab, heat-treated at 1100 ° C. for 1 hour, rolled in three passes, hot finish rolling was completed at 850 ° C., and -20 ° C./h from 500 ° C. To obtain a hot-rolled steel sheet having a thickness of 3 mm. This was ground to a thickness of 2.3 mm and cold-rolled to obtain a cold-rolled steel sheet having a thickness of 0.5 mm. This cold-rolled steel sheet was annealed by rapidly heating to 750 ° C. and holding for 20 seconds to obtain a non-oriented electrical steel sheet. A test piece of 3 cm × 10 cm was punched from the steel sheet so that the longitudinal direction was the rolling direction and the sheet width direction, and magnetic annealing was performed at 750 ° C. for 2 hours. Thus iron loss _{W 15/50} as the magnetic properties of the samples obtained was measured (1.5T, iron loss at 50 Hz). The results are shown in FIG. Incidentally, the iron loss _{W 15/50} was measured using a single-plate magnetic testing device (manufactured by Yokogawa Electric Corporation (Ltd.)). Also, the iron loss _{W 15/50} was an average value of the rolling direction and the sheet width direction.
[0023]
From the results shown in FIG. 1, it was found that a specific composite addition effect was obtained by setting Mn and Cu to the predetermined contents, and there was a region showing extremely good magnetic properties.
[0024]
Next, the following experiment was conducted to investigate the effect of inclusions on magnetic properties. In the above-described experiments, the Mn and Cu contents were in the above-described regions, and a steel having good iron loss after magnetic annealing was used to prepare a non-oriented electrical steel sheet in which the hot rolling conditions and the finish annealing conditions were variously changed. The relationship between inclusions made and dispersed in the finish-annealed steel sheet and iron loss after magnetic annealing was examined. The steel components of the steel used are, by mass%, C: 0.002%, Si: 0.82%, Mn: 0.21%, P: 0.050%, S: 0.0028%, Cr: : 0.05%, V: 0.002%, Ti: 0.0003%, sol. Al: 0.0002%, N: 0.0022%, Cu: 0.021%.
[0025]
Mn-Cu-based sulfide was mainly observed in the inclusions dispersed in the steel sheet. Among them, 10 fine sulfides which adversely affect the grain growth during magnetic annealing are subjected to composition analysis by EDS (energy dispersive X-ray spectroscopy), and the Cu mole fraction (=% The average value of Cu / (% Cu +% Mn +% S) × 100)) was determined. The target fine sulfide had a major axis of 0.05 to 0.1 μm when the extracted replica was observed with a TEM (transmission electron microscope). Although sulfides having a major axis of less than 0.05 μm were also present, they were excluded from the analysis because sufficient quantitative analysis accuracy could not be obtained.
[0026]
FIG. 2 shows the relationship between the molar concentration of Cu in the Mn-Cu-based sulfide as inclusions obtained by the analysis and the iron loss after magnetic annealing. As shown in FIG. 2, the iron loss _{W 15/50} as well as increasing Cu molar concentration in the sulfide decreases, the Cu molar concentration of 30% or more, a good value as the iron loss _{W 15/50} It has been found. This is presumed to be because the Cu-containing sulfide has a smaller interaction with the crystal grain boundary than the MnS single sulfide, and the grain boundary pinning effect is smaller.
[0027]
Further, in a region less than Cu mole fraction of 30%, but sharply the iron loss _{W 15/50} is decreased with increasing Cu mole fraction, in Cu mole fraction of 30% or more regions, Cu molar reduction rate of the iron loss W _15/50 due to the increase of the fraction was found to be not be a very big thing.
[0028]
As described above, Mn and Cu are set to the predetermined contents, and more preferably, the Cu mole fraction in the Mn-Cu-based sulfide, which is an inclusion dispersed in the steel sheet, is set to a predetermined value or more. Although it is a feature of the present invention, it is necessary to limit the components as described below in order to effectively bring out its effects and satisfy other characteristics required as an electromagnetic steel sheet.
[0029]
(Steel composition)
C: Since C precipitates as carbides and degrades magnetic properties, the lower the content, the better. In particular, when the C content exceeds 0.004%, magnetic aging occurs, so the content is set to 0.004% or less. Note that, in order to suppress the growth of (111) crystal grains which are not preferable for magnetic properties, the lower limit of the content is desirably 0.0003%.
[0030]
Since Si: Si increases the specific resistance of steel, the higher its content, the smaller the iron loss. In order to obtain the effect sufficiently, the Si content needs to be 0.7% or more. However, when the Si content is 0.7% or more, the N activity increases and various nitrides are formed, thereby deteriorating the magnetic characteristics. The present invention is characterized in that in order to prevent such deterioration of magnetic properties, the content of the nitride-forming element is sufficiently reduced, and then Mn and Cu are combined and added in an appropriate range. On the other hand, if the Si content exceeds 1.5%, the hardness of the steel sheet increases, and as a result, the abrasion of the punching die increases, and the cost of manufacturing the motor core increases. Therefore, the Si content is set to 0.7 to 1.5%.
[0031]
Mn: Since Mn also has the effect of increasing the specific resistance of steel, the higher the Mn content, the better. When the Mn content is less than 0.1%, MnS is finely dispersed and magnetic properties are deteriorated. On the other hand, if the Mn content is higher than 0.3%, SiMn-based nitrides precipitate and the magnetic properties deteriorate. Therefore, the Mn content is set to 0.1 to 0.3%. Furthermore, in order to manufacture with stable magnetic properties, the Mn content is desirably 0.15 to 0.25%.
[0032]
sol. Al: sol. Al (acid-soluble Al) is an element effective for deoxidation. However, in a steel containing 0.7% or more of Si, a nitride is easily formed, so that the lower the content, the better. Further, since it causes variation in magnetic characteristics, the content is set to less than 0.0005%.
[0033]
P: P, like Si, increases the specific resistance of steel and is effective in reducing iron loss. However, when P exceeds 0.2%, the hardness of the steel plate increases, so that the wear of the punching die becomes faster, and the motor core is increased. Manufacturing costs increase. Therefore, the P content is set to 0.2% or less.
[0034]
S: If S is higher than 0.005%, SiMn nitride is likely to precipitate with MnS as a nucleus, and magnetic properties are significantly deteriorated. Therefore, the S content is set to 0.005% or less. Desirably, the S content is 0.004% or less, and more preferably 0.003% or less in order to suppress the deterioration of magnetic properties and the variation in properties due to MnS.
[0035]
Cr: Cr is an unavoidable impurity. If the content exceeds 0.1%, Cr-based nitrides precipitate and the magnetic properties deteriorate. Therefore, the Cr content is set to 0.1% or less. Furthermore, in order to suppress composite precipitates with V and Nb and improve magnetic properties, it is preferable that the Cr content be 0.05% or less.
[0036]
V: V is an unavoidable impurity. When the content exceeds 0.005%, V carbonitride precipitates and magnetic properties are remarkably deteriorated. Therefore, the V content is set to 0.005% or less. Further, in order to suppress composite precipitates with Cr and Nb and improve magnetic properties, the V content is preferably set to 0.003% or less.
[0037]
Ti: Ti is an unavoidable impurity. When the content exceeds 0.001%, fine Ti carbonitride precipitates and magnetic properties are remarkably deteriorated. Therefore, the Ti content is set to 0.001% or less.
[0038]
N: N forms a nitride with Si, Mn, V, Cr, Al, etc., and prevents grain growth during magnetic annealing. A more preferable N content is 0.002% or less.
[0039]
Cu: Cu affects the precipitation of sulfides and nitrides, and improves magnetic properties by improving grain growth and texture after magnetic annealing. To obtain the effect, it is necessary to control the amount of Mn to an appropriate range and simultaneously add 0.016% or more.
[0040]
Although the cause of such a combined effect of Mn and Cu is not clear, the inventors speculate as follows. That is, although the role of Mn is as described above, by adding Cu in a complex manner, MnS partially changes into (Mn, Cu) S and the dispersion density of sulfide decreases. Further, the Cu-containing sulfide has a smaller interaction with the crystal grain boundary than the MnS single sulfide, and the grain boundary pinning effect is smaller. By controlling such sulfide, grain growth and texture during magnetic annealing are improved. As a result, the magnetic properties are improved.
[0041]
On the other hand, when the content exceeds 0.05%, the effect of improving iron loss after magnetic annealing is saturated. Further, the addition of a large amount of Cu exceeding 0.05% induces surface defects of the hot-rolled steel sheet, and the product yield is reduced. Therefore, the Cu content is set to 0.016 to 0.05%. Japanese Patent Application Laid-Open No. 9-263909 states that the magnetic properties during magnetic annealing are improved by controlling Cu sulfide. However, in this technology, it is necessary to increase the cooling spray capacity in order to increase the cooling rate at the time of solidification of the casting, or to adopt a method of reducing the thickness of the slab, and the cost is higher than the normal manufacturing method There is.
[0042]
Other components: Zr, B, and Nb, which have a strong tendency to form nitrides, are preferably reduced as much as possible. However, there is no particular problem unless each component exceeds the amount inevitably mixed. The unavoidable amounts to be mixed here are Zr of 0.002% or less, B of 0.001% or less, and Nb of 0.003% or less.
[0043]
(Inclusion)
Sulfides as inclusions dispersed in steel suppress grain growth during magnetic annealing and degrade magnetic properties, so their composition must be controlled. Specifically, when the Cu mole fraction contained in the fine sulfide of 0.05 to 0.1 μm is 30% or more, the iron loss during magnetic annealing becomes better.
[0044]
Such control of the Cu mole fraction in the sulfide can be performed as follows.
[0045]
Since Cu has a lower solid solubility in the ferrite phase than in the austenite phase, it is considered that the increase in the Cu concentration in the sulfide proceeds in the ferrite phase region. Therefore, in order to control the sulfide composition, the slab heating temperature is set to a low temperature in the austenite phase region to precipitate coarse MnS, the hot rolling finish temperature is set to the high temperature ferrite phase region, and the finish annealing temperature after cold rolling is further reduced. It is advantageous to work in the high temperature ferrite phase region.
[0046]
Specifically, the slab casting condition may be a normal production method, but the slab heating temperature is 1130 ° C. or less, the hot rolling finish temperature is 850 ° C. or more in the ferrite phase region, and the finish annealing after cold rolling is performed. It is effective to set it to 750 to 900 ° C. However, if the slab heating temperature is less than 1000 ° C., the slab temperature becomes more non-uniform due to a decrease in temperature at the skid portion, and the thickness accuracy deteriorates. Therefore, the lower limit of the slab heating temperature is preferably 1000 ° C. Annealing of the hot-rolled steel sheet may or may not be performed. In the case of carrying out, it is effective to anneal in a ferrite phase region of 700 to 900 ° C. for 1 hour or more, and then perform box annealing in which the cooling rate is 100 ° C./h or less. Note that hot rolling and annealing are not limited to the above conditions.
[0047]
Note that the present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention, and any device having the same operation and effect can be realized by the present invention. It is included in the technical scope of the invention.
[0048]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[0049]
(Example 1)
230 t of molten steel decarburized and desulfurized in a converter was tapped into a ladle, and the ladle was moved to an RH-type vacuum degasser. After decompressing under reduced pressure with an RH-type vacuum degassing apparatus to reduce the C concentration in steel to 0.004% or less, the components of Si, Mn, P, Cu, and Al were adjusted. As the additive material, a material having a small impurity content such as Cr, Ti, V, and Nb was used. When the temperature of the molten steel was low, an oxygen gas was applied to perform a temperature raising process. After the component adjustment and the temperature adjustment, the RH treatment was completed, and the slab was formed using a continuous casting machine.
[0050]
The slab was heated to 1100 ° C in a heating furnace, and hot-rolled at a finishing temperature of 850 to 880 ° C and a winding temperature of 500 ° C to a thickness of 2.3 mm. Then, after descaling, cold rolling was performed to 0.5 mm without performing hot-rolled sheet annealing, and final annealing was performed at 780 ° C. After the finish annealing, an insulating film was applied to the steel sheet surface. A 28 cm Epstein test piece was collected from this steel sheet and subjected to magnetic annealing (held at 750 ° C. for 2 hours in a nitrogen atmosphere). Magnetic properties were measured by the Epstein method (a method specified in JIS-C-2550).
[0051]
Table 1 shows the steel component analysis values and the iron loss after magnetic annealing. Steel 1 to 10 which is an embodiment of the present invention is excellent both iron loss _{W 15/50} after the magnetic annealing 3.90W / kg or less. On the other hand, the iron losses of the steels 11 to 22 of the comparative examples are all inferior to 4.06 to 5.38 W / kg.
[0052]
[Table 1]

[0053]
(Example 2)
Using a steel 1 slab having a steel composition within the range of the present invention, a non-oriented electrical steel sheet having a thickness of 0.5 mm was manufactured under various conditions of hot rolling and finish annealing. Specifically, the slab heating temperature is 1100 to 1250 ° C, the hot rolling finish temperature is 800 to 880 ° C, the thickness of the hot rolled steel sheet is 2.3 mm, and the finish annealing temperature after cold rolling is 700 to 900 ° C. did. The sulfide dispersed in the manufactured steel sheet was observed by TEM using an extraction replica, and the composition of ten fine sulfides (major axis: 0.05 to 0.1 μm) was analyzed by EDS to find the average Cu mole fraction. . The magnetic properties after the magnetic annealing were measured by the Epstein method. Table 2 shows the manufacturing conditions, Cu mole fraction, and magnetic properties. Production conditions and iron loss _{W 15/50} in FIG. 3 shows the relationship between the Cu mole fraction. Although there is no clear correlation between the individual manufacturing conditions and the iron loss, No. 1 manufactured under appropriate combinations of manufacturing conditions. The steel sheets of Nos. 1, 8, and 9 have a Cu mole fraction of 30% or more, and the iron loss after magnetic annealing is good at 3.70 W / kg or less.
[0054]
[Table 2]

[0055]
【The invention's effect】
Since the electrical steel sheet of the present invention has such an extremely low Al content, it is excellent in recyclability, and even when containing 0.7% or more of Si, the content of Mn and Cu is kept at a predetermined value. Range, and the contents of V, Cr, Al, and Ti, which are nitride-generating elements, are also sufficiently reduced, so that nitrides that adversely affect magnetic properties can be significantly reduced. An electromagnetic steel sheet having magnetic properties can be obtained.
[Brief description of the drawings]
1 is a graph showing the relationship between the content and the iron loss _{W 15/50} of Cu and Mn in the steel.
2 is a graph showing the relationship between the Cu molar concentration and the iron loss W _15/50 in the sulfide as inclusions dispersed in the steel.
[3] (a) ~ (c) is a graph showing the relationship between the various production conditions and the iron loss W _15/50, (d) the Cu molar in sulfides as inclusions dispersed in the steel is a graph showing the relationship between a fraction and the iron loss _{W 15/50.}

Claims (2)

% By mass, C: 0.004% or less, Si: 0.7 to 1.5%, Mn: 0.1 to 0.3%, sol. Al: less than 0.0005%, P: 0.2% or less, S: 0.005% or less, N: 0.003% or less, Cr: 0.1% or less, V: 0.005% or less, Ti: A non-oriented electrical steel sheet comprising 0.001% or less and Cu: 0.016 to 0.05%, with the balance being Fe and unavoidable impurities. The Cu mole fraction (=% Cu / (% Cu +% Mn +% S) × 100) in the sulfide having a major axis of 0.05 to 0.1 μm existing as an inclusion in steel is not less than 30%. The non-oriented electrical steel sheet according to claim 1.

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