Non-oriented electrical steel sheet and method for producing same

Abstract

The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same, the method comprising: a step for heating a slab which contains, in wt%, 0.005% or less of C, 2.5-4.0% or less of Si, 0.1% or less of P, 0.1-2.0% of Al, 0.2-2.5% of Mn, 0.003% or less of N, 0.005% or less of Ti and Nb, 0.003% or less of S, 0.005-0.025% of V, and 0.1% or less of Cu, with the balance being Fe and other unavoidable impurities, and which satisfies formula 1; a step in which the slab is hot-rolled to produce a hot-rolled sheet; a step for manufacturing a cold-rolled sheet by cold-rolling the hot-rolled sheet; [Formula 1] (51 * [C]) / 12-0.002 < = [V] < = (51 * [C]) / 12 + 0.004, in Formula 1, [C] and [V] represent the content (wt%) of C and V, respectively.

Description

[0001] This application is a divisional application of a Chinese patent application filed on December 14, 2020, with Chinese patent application number 202080096012.2 and invention name “Non-oriented electrical steel sheet and method for manufacturing the same”, and this application claims priority to Korean application number 10-2019-0169954. Technical Field

[0002] The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same. Specifically, the present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same, which has good high-frequency iron loss by controlling the content of alloy elements constituting the electrical steel sheet to control the size of precipitates. Background Art

[0003] Recently, with the increasing focus on efficient use of energy, efforts are being made to improve the efficiency of motors used in electrical equipment such as large generators or environmentally friendly vehicles such as hybrid electric vehicles (HEV) or electric vehicles (EV). As part of this, efforts are being made to achieve faster rotation speeds than ordinary motors through frequency modulation, just like BLDC motors.

[0004] In particular, for motors used in drive units of hybrid vehicles or electric vehicles, high power needs to be obtained with limited size, and a rotation speed of more than 10,000 rpm is also required. In this case, the iron loss in the operating frequency domain above 400 Hz is important, and the loss at a frequency above 1,000 Hz is also important because of the presence of harmonic components in the current of inverters, etc. and the generation of harmonic components at the rotor / stator ends. In order to reduce losses in this area, it is necessary to reduce eddy current losses caused by high frequencies. In order to reduce high-frequency losses, the most effective way is to reduce the thickness, but due to the cost and manufacturability of steel sheets, it is necessary to study how to minimize the thickness and reduce the iron loss. As one of the links, efforts have been made to improve the iron loss of high-alloy non-oriented electrical steel sheets containing a large amount of Si / Al / Mn, etc. by improving cleanliness or texture at the same thickness using segregation elements or elements with high oxygen affinity.

[0005] To this end, research has been conducted in the past to actively use Mo, Y, Bi, P, etc., and technologies such as improving texture by segregation and improving iron loss by coarsening precipitates have been proposed.

[0006] However, the segregation elements such as Bi and P segregate at the grain boundaries, resulting in deterioration of cold rolling properties. When applied to high-alloy non-oriented electrical steel sheets with a high Si content, there is a problem of reduced yield. For Y, the formation of additional oxides will lead to deterioration of magnetic properties. For Mo, the effect is not obvious. When Mo is added, the improvement in magnetic properties is less than the iron loss deviation, so the economic efficiency is low. Summary of the invention

[0007] Technical issues

[0008] An object of the present invention is to suppress magnetic degradation caused by carbon after final annealing and to improve iron loss characteristics by controlling the content of alloy elements contained in a non-oriented electrical steel sheet.

[0009] Technical Solution

[0010] A nonoriented electrical steel sheet according to an embodiment of the present invention may contain, by weight%, C: 0.005% or less, Si: 2.5-4.0% or less, P: 0.1% or less, Al: 0.1-2.0%, Mn: 0.2-2.5%, N: 0.003% or less, Ti or Nb: 0.005% or less, S: 0.003% or less, V: 0.005-0.025%, Cu: 0.1% or less, the balance of Fe and other inevitably mixed impurities, and may satisfy the following formula 1.

[0011] [Formula 1]

[0012] (51*[C]) / 12-0.002≤[V]≤(51*[C]) / 12+0.004

[0013] In Formula 1, [C] and [V] represent the contents of C and V, respectively (wt %).

[0014] The non-oriented electrical steel sheet may have an average particle size of VC precipitates of 1 to 10 nm.

[0015] The non-oriented electrical steel sheet has a VC precipitate density of 4*10 15 Up to 1*10 19 pcs / m 3 .

[0016] The non-oriented electrical steel sheet has an average particle size of AlN precipitates of less than 40 nm and a density of 10×10 14 pcs / m 3 the following.

[0017] The non-oriented electrical steel sheet is a precipitate of any one of NbC and TiC, the average particle size of which can be less than 15 nm, and the density of which can be 15×10 15 pcs / m3 the following.

[0018] The non-oriented electrical steel sheet has an average particle size of CuS precipitates of less than 10 nm and a density of 10×10 15 pcs / m 3 the following.

[0019] The non-oriented electrical steel sheet may have an average crystal grain size of 50 to 150 μm.

[0020] The non-oriented electrical steel sheet is iron loss (W 10 / 400 ) can be below 12W / kg.

[0021] A method for manufacturing a nonoriented electrical steel sheet according to an embodiment of the present invention may include: a step of heating a slab, wherein the slab contains, by weight%, C: 0.005% or less, Si: 2.5-4.0% or less, P: 0.1% or less, Al: 0.1-2.0%, Mn: 0.2-2.5%, N: 0.003% or less, Ti, Nb: 0.005% or less, S: 0.003% or less, V: 0.005-0.025%, Cu: 0.1% or less, and the balance of Fe and other unavoidably mixed impurities, and satisfies the following formula 1; a step of hot rolling the slab to manufacture a hot rolled sheet; a step of cold rolling the hot rolled sheet to manufacture a cold rolled sheet; and a step of final annealing the cold rolled sheet.

[0022] [Formula 1]

[0023] (51*[C]) / 12-0.002≤[V]≤(51*[C]) / 12+0.004

[0024] In Formula 1, [C] and [V] represent the contents of C and V, respectively (wt %).

[0025] In the step of heating the slab, the heating temperature of the slab may be 1100 to 1250°C.

[0026] After the step of hot rolling the slab to produce a hot rolled plate, the step of annealing the hot rolled plate may be included, and the annealing temperature of the hot rolled plate may be 850 to 1200°C.

[0027] In the step of cold-rolling the hot-rolled sheet to produce a cold-rolled sheet, the cold rolling may be performed once or twice or more including intermediate annealing.

[0028] In the step of performing final annealing on the cold rolled sheet, the final annealing temperature may be 900 to 1050°C.

[0029] After the step of performing final annealing on the cold-rolled sheet, a step of coating an insulating film on the steel sheet after the final annealing may be included.

[0030] The average grain size of the steel sheet after the final annealing may be 50 to 150 μm.

[0031] Effects of the Invention

[0032] According to one embodiment of the present invention, by adding V (vanadium) in proportion to the C (carbon) content, the VC precipitates can be controlled to a size that does not affect the magnetic properties.

[0033] Furthermore, according to one embodiment of the present invention, by effectively suppressing magnetic degradation caused by C after final annealing, it is possible to improve iron loss characteristics and stably ensure iron loss characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A graph of carbon content and vanadium content according to an embodiment of the present invention is used to show the relationship with iron loss. DETAILED DESCRIPTION

[0035] The words first, second, third, etc. are used to describe various parts, components, regions, layers and / or segments, but these parts, components, regions, layers and / or segments should not be limited by these words. These words are only used to distinguish a certain part, component, region, layer and / or segment from another part, component, region, layer and / or segment. Therefore, without departing from the scope of the present invention, the first part, component, region, layer and / or segment described below can also be described as the second part, component, region, layer and / or segment.

[0036] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. Unless the context otherwise clearly indicates the opposite, the singular form used herein is also intended to include the plural form. "Including" used in the specification may specifically refer to a certain characteristic, field, integer, step, action, element and / or component, but does not exclude the existence or addition of other characteristics, fields, integers, steps, actions, elements, components and / or groups.

[0037] If a part is described as being on another part, it may be directly on the other part or there may be other parts therebetween. When a part is described as being directly on another part, there may be no other parts therebetween.

[0038] In addition, unless otherwise specified, % means weight %, and 1 ppm means 0.0001 weight %.

[0039] Although not otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. Terms defined in dictionaries should be interpreted as having the same meaning as that disclosed in the relevant technical literature and this article, and should not be interpreted in an idealized or overly formal sense.

[0040] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in various ways and is not limited to the embodiments described herein.

[0041] The present invention aims to provide a method for manufacturing a non-oriented electrical steel sheet, and in the manufacturing of a non-oriented electrical steel sheet in which high-frequency iron loss is important for driving motors of environmentally friendly vehicles, it is found that the high-frequency iron loss can be reduced by appropriately controlling C precipitates using V, taking into account the influence of various alloy elements and the recrystallization behavior or structure change characteristics caused by adjusting various process factors of hot rolling, cold rolling and final annealing.

[0042] In addition, the present invention studied the high-frequency iron loss characteristics of high-silicon non-oriented electrical steel sheets with a Si content of more than 2.5% by weight and found that the C-based precipitates present in the steel sheet are an important factor affecting the iron loss, so it is intended to control the C-based precipitates. Generally, it is known that C-based precipitates with a high redissolution temperature will weaken the (001) texture that is beneficial to magnetism, thereby hindering the movement of magnetic domains, thereby causing the iron loss to deteriorate. However, precipitates with a low redissolution temperature not only improve the texture when the annealing temperature of the hot-rolled sheet is high, but also play a positive role in magnetism due to the small size of the precipitates.

[0043] Based on this, the present invention has found that VC precipitates formed by the combination of V and C can play the above-mentioned role due to the low redissolution temperature, so the present invention intends to use VC precipitates in non-oriented electrical steel sheets and their manufacturing methods. For VC precipitates, when the V content is properly controlled, the redissolution temperature is as low as about 700°C, which not only has the effect of improving the texture during recrystallization, but also can improve the magnetic properties due to the size of 10nm or less.

[0044] Hereinafter, each step will be described in detail.

[0045] The method for manufacturing a non-oriented electrical steel sheet according to the present invention may include: a step of heating a slab, wherein the slab contains, by weight%, C: less than 0.005%, Si: less than 2.5-4.0%, P: less than 0.1%, Al: 0.1-2.0%, Mn: 0.2-2.5%, N: less than 0.003%, Ti, Nb: less than 0.005%, S: less than 0.003%, V: 0.005-0.025%, Cu: less than 0.1%, the balance of Fe and other unavoidable impurities, and satisfies the following formula 1; a step of hot rolling the slab to manufacture a hot-rolled sheet; a step of cold rolling the hot-rolled sheet to manufacture a cold-rolled sheet; and a step of finally annealing the cold-rolled sheet.

[0046] [Formula 1]

[0047] (51*[C]) / 12-0.002≤[V]≤(51*[C]) / 12+0.004

[0048] In Formula 1, [C] and [V] represent the contents of C and V, respectively (wt %).

[0049] Through the manufacturing process, carbon (C) present in the steel material combines with vanadium (V) to form VC precipitates, and the average particle size of the formed VC precipitates may be less than 10 nm. Specifically, the average particle size of the VC precipitates may be 1 to 10 nm, or 2 nm to 8 nm. In addition, the density of the VC precipitates may be 4*10 15 Up to 1*10 19 pcs / m 3 .

[0050] In addition, for the non-oriented electrical steel sheet of the present invention, Al in the steel can combine with N to form AlN precipitates. The formed AlN precipitates will inhibit crystal growth or hinder the movement of magnetic domains, thereby causing magnetic attenuation. Therefore, in the non-oriented electrical steel sheet of the present invention, the average particle size of the AlN precipitates is as small as possible, and can be less than 40nm. The average particle size can be specifically 1 to 40nm, further specifically 1 to 35nm, and more specifically 1 to 32nm. In addition, the density of the AlN precipitates in the non-oriented electrical steel sheet of the present invention can be 10*10 14 pcs / m 3 Below, specifically 4 to 8*10 14 pcs / m 3 , more specifically 5 to 7*10 14 pcs / m 3 .

[0051] In addition, for the non-oriented electrical steel sheet of the present invention, Nb and Ti in the steel can combine with C to form NbC and TiC precipitates. Since the formed NbC and TiC precipitates are finely precipitated at a temperature of about 900°C, it may have a fatal effect on the magnetism, so it is necessary to control the size and density. Therefore, in the non-oriented electrical steel sheet of the present invention, the smaller the average particle size of any one or more of the precipitates of NbC and TiC, the better, for example, it can be 15nm or less. The average particle size can be specifically 1 to 15nm, more specifically 1 to 13nm, and more specifically 1 to 11nm. In addition, the density of any one or more of the precipitates of NbC and TiC in the non-oriented electrical steel sheet of the present invention can be 15*10 15 pcs / m 3 Below, specifically 9 to 11*10 15 pcs / m 3 , more specifically 9 to 10*10 15 pcs / m 3 .

[0052] In addition, for the non-oriented electrical steel sheet of the present invention, Cu in the steel can combine with S to form CuS precipitates. The formed CuS precipitates are precipitated in the form of sulfides smaller than the generally coarse MnS, which may cause magnetic attenuation, so it is necessary to control the size and density. Therefore, in the non-oriented electrical steel sheet of the present invention, the average particle size of the CuS precipitates can be less than 10nm. The average particle size can be specifically 5 to 9nm, and more specifically 5 to 7nm. In addition, the density of the CuS precipitates of the non-oriented electrical steel sheet of the present invention can be 10*10 15 pcs / m 3 The density can be 4 to 8*10 15 pcs / m 3 , more specifically 4 to 6*10 15 pcs / m 3 .

[0053] First, the reasons for limiting the composition of the nonoriented electrical steel sheet of the present invention are described. Unless otherwise specified, the content hereinafter means weight %.

[0054] [C: 0.005 wt% or less]

[0055] C causes magnetic aging in the final product and reduces the magnetic properties during use, so the C content should be 0.005 wt% or less. The lower the C content, the more favorable the magnetic properties are, so it is more preferably limited to 0.004 wt% or less in the final product.

[0056] [Si: 2.5 to 4.0 wt % or less]

[0057] Si is added as a component to increase resistivity and reduce eddy current loss in iron loss. In the present invention, in order to fully improve high-frequency low iron loss, it is necessary to add 2.5 wt% or more. However, when the Si content is greater than 4.0 wt%, even if the structure before cold rolling is improved, the cold rolling property will be reduced, resulting in steel sheet fracture, so it is preferred to limit the Si content to less than 4.0 wt%.

[0058] [P: 0.1 wt% or less]

[0059] P is added to improve magnetic properties by increasing resistivity and improving texture. However, when added in excessive amounts, cold rolling properties deteriorate, so the P content is preferably limited to 0.1 wt % or less.

[0060] [S: 0.003 wt% or less]

[0061] S forms fine precipitates of MnS and CuS, which inhibit crystal growth and deteriorate magnetic properties, so it is preferably controlled to a low level. In the present invention, the S content is limited to 0.003 wt% or less.

[0062] [Al: 0.3 to 2.0 wt%]

[0063] Al is an effective component for increasing resistivity and reducing eddy current loss. Its effect is lower than that of Si, but it has the effect of improving strength when added. When the amount of Al added is less than 0.3 wt%, AlN is finely precipitated and causes magnetic attenuation. On the contrary, when the amount of Al added is greater than 2.0 wt%, the processability deteriorates, so it is preferred to limit the Al content to 0.3 to 2.0 wt%.

[0064] [Mn: 0.2 to 2.5 wt%]

[0065] If the amount of Mn added is less than 0.2 wt%, fine MnS precipitates will be formed, thereby inhibiting crystal growth, resulting in deterioration of magnetic properties. Therefore, it is preferred to add more than 0.2 wt% to make the MnS precipitate coarse. In addition, if the amount of Mn added is more than 0.2 wt%, the S component will be prevented from precipitating into a finer precipitate CuS, thereby preventing magnetic decay. However, when Mn is added in excess, the magnetic properties will be reduced, so it is preferred to limit the Mn content to 0.2 to 2.5 wt%.

[0066] [N: 0.003 wt% or less]

[0067] It is preferable to contain as little N as possible because N forms elongated AlN precipitates inside the base material to inhibit grain growth, thereby causing deterioration of iron loss. In the present invention, the N content is limited to 0.003 wt % or less.

[0068] [Ti, Nb: 0.005 wt% or less]

[0069] Ti and Nb form fine Ti(Nb)CN precipitates to inhibit grain growth. When the content of Ti and Nb is greater than 0.005 wt%, many fine precipitates will be produced, resulting in poor texture and further deterioration of magnetic properties, which inhibits crystal growth during customer heat treatment processes. Therefore, the Ti content is limited to less than 0.005 wt%.

[0070] [Cu: 0.1 wt% or less]

[0071] In the present invention, when Cu is added excessively, magnetic properties may be deteriorated due to the precipitation of fine precipitates CuS. Therefore, Cu can be added in an amount of 0.1 wt % or less. Specifically, Cu can be added in an amount greater than 0 and less than 0.1 wt %, and more specifically, greater than 0 and less than 0.02 wt %.

[0072] [V: 0.005 to 0.25 wt%]

[0073] In the present invention, V is an essential element for improving the texture and iron loss by combining with C to form VC with a low redissolution temperature. By generating VC precipitates, it plays a role in binding C, thereby suppressing the formation of Fe carbides that cause the iron loss to deteriorate. Finally, by forming VC precipitates, the formation of Fe carbides is suppressed, thereby improving the iron loss. In order to play such a role, V should be added in the range of 0.005 to 0.25 wt% and in the range satisfying the following formula 1. At this time, the size of the VC precipitates is controlled to be less than 10 nm, and the density is controlled to be 4*10 15 Up to 1*10 19 pcs / m 3 range to reduce the impact on iron loss.

[0074] [Formula 1]

[0075] (51*[C]) / 12-0.002≤[V]≤(51*[C]) / 12+0.004

[0076] In Formula 1, [C] and [V] represent the contents of C and V, respectively (wt %).

[0077] Hereinafter, a method for manufacturing a non-oriented electrical steel sheet according to the present invention will be described.

[0078] The method for manufacturing the non-oriented electrical steel sheet of the present invention firstly loads the slab having the above composition into a heating furnace for heating. The heating temperature of the slab is preferably 1100 to 1250° C. When the slab is heated to a temperature higher than 1250° C., the precipitates which are not conducive to magnetism are redissolved and may be finely precipitated after hot rolling.

[0079] After the slab is heated, hot rolling is performed, and the hot-rolled plate after hot rolling is coiled. If necessary, the hot-rolled plate is annealed after coiling. For hot-rolled plate annealing, when manufacturing high-grade electrical steel plates without phase change, it is preferred to perform hot-rolled plate annealing, which is very effective in improving the texture of the final annealed plate and increasing the magnetic flux density. When hot-rolled plate annealing is performed, it is preferably performed at a temperature of 850 to 1200°C. If the hot-rolled plate annealing temperature is lower than 850°C, the structure will not grow or will grow finely, and it is difficult to expect an increase in magnetic flux density. If the hot-rolled plate annealing temperature is higher than 1200°C, the magnetic properties will decay instead, and the rolling operability may deteriorate due to plate-shaped deformation.

[0080] After the hot rolled sheet is annealed as described above, the hot rolled sheet is pickled and cold rolled to produce a cold rolled sheet having a desired thickness. The cold rolling may be performed once, or may be performed twice or more including intermediate annealing as required.

[0081] Final annealing is performed on the cold-rolled sheet after cold rolling. Final annealing is performed at a temperature of 900 to 1050°C to make the grain size in the cross section of the steel sheet reach 50 to 150μm. If heat treatment is performed at a temperature below 900°C, the iron loss will deteriorate due to small grains, and if heat treatment is performed at a temperature above 1050°C, the grain size becomes coarse, the abnormal eddy current loss becomes large, and the overall iron loss becomes high.

[0082] After the final annealing, the steel sheet can be treated with an insulating film by conventional methods and then shipped to customers. When applying the insulating film, conventional coating materials can be used, and any of chromium type (Cr-type) and chromium-free type (Cr-freetype) can be used without restriction.

[0083] Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited to the following examples.

[0084] Example

[0085] The slab is reheated to 1130°C, and the slab contains alloy components and impurities as shown in Tables 1 and 2 below in weight%, and then hot rolled to a thickness of 2.0 mm to produce a hot-rolled plate. Each hot-rolled plate produced is coiled at 620°C, cooled in air, and hot-rolled plate annealing is performed at 1020°C for 2 minutes. Next, the hot-rolled plate is pickled and then cold rolled to a thickness of 0.25 mm. Next, the cold-rolled plate is finally annealed under an ambient condition of 20% hydrogen and 80% nitrogen at a temperature of 1000°C, and then the magnetism and precipitates are analyzed. For iron loss, a 60*60mm 2The single plate measuring device was used to measure in the rolling direction and the direction perpendicular to the rolling direction, and the average value was calculated. The size of the VC precipitates was measured by the replication method of the transmission electron microscope. The results are shown in Table 2.

[0086]

Table 1

[0087]

[0088]

Table 2

[0089]

[0090]

[0091] Figure 1 The comparative materials 1 to 21 and the inventive materials 1 to 10 in Table 2 are shown in a graph of the V content [V] according to the C content [C]. Figure 1 As shown, in the case of the invention materials 1 to 10, in which the V content is greater than (51*[C]) / 12-0.002 and less than (51*[C]) / 12+0.004, the iron loss shows a low iron loss value of 12.0 W / kg or less, and it can be confirmed that it is included in this region. In the case of comparative materials 10 and 19, although the V content satisfies the range, since the C content is higher than 0.005% and the size of VC is 10 nm or more, the iron loss deteriorates and exceeds 12.0 W / kg.

[0092] Therefore, in order to achieve high-frequency iron loss (W) suitable for environmentally friendly vehicle drive motors, 10 / 400 ) has good properties as low as 12 W / kg or less. Like the inventive materials 1 to 10 in Table 2, V needs to be added in proportion to the amount of C, but the C content shall not be greater than 0.005%.

[0093] The present invention can be implemented in various ways and is not limited to the above-mentioned embodiments. A person skilled in the art of the present invention can understand that the present invention can be implemented in other specific ways without changing the technical concept or essential features of the present invention. Therefore, it should be understood that the above-mentioned embodiments are exemplary in all aspects and are not restrictive.

Claims

1. A non-oriented electrical steel sheet, wherein: The steel plate comprises, in weight%, C: 0.005% or less, Si: 2.5-4.0% or less, P: 0.1% or less, Al: 0.1-2.0%, Mn: 0.6-2.5%, N: 0.003% or less, Ti or Nb: 0.005% or less, S: 0.003% or less, V: 0.005-0.025%, Cu: 0.02% or less, excluding 0%, the balance of Fe and other unavoidably mixed impurities, and satisfies the following formula 1, wherein: In the non-oriented electrical steel sheet, the density of VC precipitates is 4*10 15 Up to 1*10 19 pcs / m 3 , Wherein, in the non-oriented electrical steel sheet, the average particle size of VC precipitates is 1 to 10 nm, [Formula 1] (51*[C]) / 12-0.002≤[V]≤(51*[C]) / 12+0.004 In Formula 1, [C] and [V] represent the weight % contents of C and V, respectively.

2. The non-oriented electrical steel sheet according to claim 1, wherein: In the non-oriented electrical steel sheet, the average particle size of AlN precipitates is less than 40 nm and the density is 10×10 14 pcs / m 3 the following.

3. The non-oriented electrical steel sheet according to claim 1, wherein: In the non-oriented electrical steel sheet, the average particle size of one or more precipitates of NbC and TiC is less than 15 nm, and the density is 15×10 15 pcs / m 3 the following.

4. The non-oriented electrical steel sheet according to claim 1, wherein: In the non-oriented electrical steel sheet, the average particle size of CuS precipitates is less than 10 nm and the density is 10×10 15 pcs / m 3 the following.

5. The non-oriented electrical steel sheet according to claim 1, wherein: The non-oriented electrical steel sheet has an average grain size of 50 to 150 μm.

6. The non-oriented electrical steel sheet according to claim 1, wherein: The iron loss W of the non-oriented electrical steel sheet 10 / 400 It is below 12W / kg.

7. A method for manufacturing a non-oriented electrical steel sheet, comprising: The step of heating a slab, wherein the slab comprises, in weight %, C: 0.005% or less, Si: 2.5-4.0% or less, P: 0.1% or less, Al: 0.1-2.0%, Mn: 0.6-2.5%, N: 0.003% or less, Ti, Nb: 0.005% or less, S: 0.003% or less, V: 0.005-0.025%, Cu: 0.02% or less, excluding 0%, the balance of Fe and other unavoidable impurities, and satisfies the following formula 1; hot rolling the slab to produce a hot-rolled plate; The step of cold rolling the hot rolled sheet to produce a cold rolled sheet; The step of performing final annealing on the cold rolled sheet, The density of VC precipitates in the steel plate after the final annealing is 4*10 15 Up to 1*10 19 pcs / m 3 , in, In the non-oriented electrical steel sheet, the average particle size of VC precipitates is 1 to 10 nm. [Formula 1] (51*[C]) / 12-0.002≤[V]≤(51*[C]) / 12+0.004 In Formula 1, [C] and [V] represent the weight % contents of C and V, respectively.

8. The method for manufacturing a non-oriented electrical steel sheet according to claim 7, wherein: In the step of heating the slab, The heating temperature of the slab is 1100 to 1250°C.

9. The method for manufacturing a non-oriented electrical steel sheet according to claim 7, wherein: After the step of hot rolling the slab to produce a hot-rolled plate, the step of annealing the hot-rolled plate is included, and the annealing temperature of the hot-rolled plate is 850 to 1200°C.

10. The method for manufacturing a non-oriented electrical steel sheet according to claim 7, wherein: In the step of cold rolling the hot rolled sheet to produce a cold rolled sheet, The cold rolling is performed once, or twice or more with intermediate annealing performed in between.

11. The method for manufacturing a non-oriented electrical steel sheet according to claim 7, wherein: In the step of performing final annealing on the cold rolled sheet, the final annealing temperature is 900 to 1050°C.

12. The method for manufacturing a non-oriented electrical steel sheet according to claim 7, wherein: After the step of performing final annealing on the cold-rolled sheet, the method further includes the step of coating an insulating film on the final annealed steel sheet.

13. The method for manufacturing a non-oriented electrical steel sheet according to claim 7, wherein: The average grain size of the steel sheet after the final annealing is 50 to 150 μm.

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