Non-oriented electrical steel sheet and its manufacturing method

Abstract

The present invention provides a non-oriented electrical steel sheet and a method for producing the same, in which Si, Al, Mn, Cu, and Cr components for increasing resistivity and In, Sn, Sb, P, and Mg components for improving texture are added to the steel sheet, and the process conditions are also controlled to improve both strength and core loss of the steel sheet. [Solution] A method for producing a non-oriented electrical steel sheet of the present invention includes a step of producing a slab in a steelmaking process by adding, by weight, 2.8-3.8% Si, 0.5-1.5% Al, 0.3-2.0% Mn, 0.01-0.2% Cu, and 0.01-0.5% Cr, and adding 0.0005-0.015% In, 0.0050-0.08% Sn, 0.0050-0.05% Sb, and 0.0050-0.06% P to the basic components, and controlling Mg to a range of 0.002-0.05%, a slab heating step of heating the slab, a hot rolling step of final finish rolling the slab, a hot rolled sheet annealing step of annealing the hot rolled sheet, a cold rolling step of rolling the hot rolled sheet, and a final annealing step of annealing the cold rolled sheet.

Description

[Technical field]

[0001] The present invention relates to a non-oriented electrical steel sheet and a manufacturing method thereof, and more particularly to a non-oriented electrical steel sheet in which components that increase resistivity and components that improve texture are added to a steel sheet, and the process conditions are also controlled to provide a steel sheet with excellent strength and core loss at the same time, and a manufacturing method thereof. [Background technology]

[0002] Recently, there has been increasing global interest and efforts towards carbon neutrality in order to protect the global environment due to climate change. In relation to carbon neutrality, efficient use of electrical energy has become a major issue for improving the global environment, including energy conservation, reduction of fine particulate matter emissions, and reduction of greenhouse gas emissions. Currently, more than 50% of the total electric energy generated is consumed by electric motors, and therefore, in order to use electricity efficiently, it is essential to improve the efficiency of electric motors. Recently, interest in high-efficiency drive motors has increased dramatically as the field of environmentally friendly vehicles (hybrids, plug-in hybrids, electric vehicles, and fuel cell vehicles) has rapidly developed. The electrification of automobiles, which is progressing rapidly centered on electric vehicles, is drawing attention to ways to improve the characteristics of drive motors.

[0003] The characteristics required for electric vehicle traction motors are to increase the driving distance and the top speed at the same time. These goals are directly related to the low core loss and high strength properties of the electrical steel sheets used in the traction motors. If the yield strength of electrical steel sheets is high, the rotation speed of the traction motor can be increased, and the core loss is low, which improves efficiency and increases the driving distance. Therefore, it is essential that electrical steel sheets have high strength and low iron loss at high frequencies. To this end, electrical steel sheets are being made to contain a higher amount of Si than usual, and large amounts of Al, Mn, and Cr are also being added to ensure low iron loss at high frequencies and high strength at the same time. However, there is a limit to how much the strength of electrical steel sheets can be increased by reducing the grain size through the addition of large amounts of resistivity elements such as Si, Al, Mn, and Cr, and this limit is also in meeting the ever-increasing maximum speed and long-distance driving requirements of drive motors, and therefore there is a limit to how much the physical properties of electrical steel sheets can be improved.Therefore, there is an increasing need to improve the properties of the material itself by changing the internal structure of non-oriented electrical steel sheets for electric vehicle drive motors. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a non-oriented electrical steel sheet and a method for manufacturing the same. Specifically, the present invention provides a non-oriented electrical steel sheet and a method for manufacturing the same, in which Si, Al, Mn, Cu, and Cr components that increase resistivity and In, Sn, Sb, P, and Mg components that improve texture are added to the steel sheet, and the process conditions are also controlled to provide a non-oriented electrical steel sheet and a method for manufacturing the same, in which both the strength and core loss of the steel sheet are excellent. [Means for solving the problem]

[0005] The non-oriented electrical steel sheet of the present invention contains, by weight, 2.8-3.8% Si, 0.5-1.5% Al, 0.3-2.0% Mn, 0.01-0.2% Cu, 0.01-0.5% Cr, 0.0005-0.015% In, 0.0050-0.08% Sn, 0.0050-0.05% Sb, 0.0050-0.06% P, and 0.002-0.05% Mg, with the remainder being Fe and other unavoidable impurities. In the non-oriented electrical steel sheet of the present invention, the contents of In, Sn, Sb, P, and Mg and the sizes of crystal grains satisfy the relationship of the following [Formula 1]. [Formula 1] [Mg]≦([In]*[Sn]) / ([Sb]*[P])≦Crystal grain size (mm)*20

[0006] The non-oriented electrical steel sheet of the present invention further contains one or more of C: 0.0040 or less (0% excluded), S: 0.0040 or less (0% excluded), N: 0.0040 or less (0% excluded), and Ti: 0.0040 or less (0% excluded). The resistivity is 50μΩ·cm or more. Also, ND / / <114> The texture fraction is 5% or more, The following crystal direction-specific yield strength relationship [Equation 2] is satisfied. [Formula 2] Ys(RD*10.3)≦Ys(45゜)≦Ys(TD)

[0007] The method for producing the non-oriented electrical steel sheet of the present invention includes, in the steelmaking process, adding, by weight, 2.8-3.8% Si, 0.5-1.5% Al, 0.3-2.0% Mn, 0.01-0.2% Cu, 0.01-0.5% Cr, and, to the basic components, 0.0005-0.015% In, 0.0050-0.08% Sn, 0.0050-0.05% Sb, and 0.0050-0.06% P. The method includes a step of manufacturing a slab by controlling Mg in the range of 0.002 to 0.05%; a slab heating step of heating the slab; a hot rolling step of final finish rolling the slab at 800°C or more; a hot rolled sheet annealing step of annealing the hot rolled sheet; a cold rolling step of rolling the hot rolled sheet at a rolling reduction of 70 to 95%; and a final annealing step of annealing the cold rolled sheet at 800 to 1,000°C. The following [Formula 1] is satisfied. [Formula 1] [Mg]≦([In]*[Sn]) / ([Sb]*[P])≦Crystal grain size (mm)*20

[0008] The method for producing a non-oriented electrical steel sheet of the present invention further includes one or more of C: 0.0040 or less (0% excluded), S: 0.0040 or less (0% excluded), N: 0.0040 or less (0% excluded), and Ti: 0.0040 or less (0% excluded), The resistivity of the magnetic steel sheet is 50μΩ·cm or more or ND / / <114> The texture fraction is 5% or more, or one or more of the following yield strength-related conditions [Formula 2] are satisfied. [Formula 2] Ys(RD*1.03)≦Ys(45゜)≦Ys(TD) The slab is heated to 1,100 to 1,250°C. The hot-rolled sheet is annealed at 850 to 1,150°C. Effect of the Invention

[0009] According to the non-oriented electrical steel sheet of the present invention, it is possible to provide an excellent non-oriented electrical steel sheet for electric vehicle drive motors in which the basic components are Si, Al, Mn, Cu, and Cr which increase resistivity, to which In, Sn, Sb, and P which promote segregation are added while at the same time Mg which inhibits segregation is added, and the manufacturing process conditions are controlled in a state in which an optimal component ratio based on the crystal grain size is derived, thereby simultaneously increasing yield strength and iron loss. In addition, the yield strength is further increased as the rolling direction is changed to the direction perpendicular to the rolling direction, which improves suitability for high speed rotation, and at the same time, the core loss is improved to provide excellent properties. In addition, when used as a drive motor, it is possible to operate the motor with a small current even at high speeds, resulting in excellent motor efficiency. Ultimately, this will contribute to the production of environmentally friendly motors for automobiles, highly efficient motors for home appliances, and super-premium electric motors. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Thus, a first part, component, region, layer, or section described below can be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention. The terminology used herein is merely for the purpose of referring to particular embodiments and is not intended to limit the present invention. As used herein, the singular form includes the plural form unless the phrase clearly indicates otherwise. As used in the specification, the term "comprising" refers to the specification of particular features, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components. When an element is referred to as being "on" or "on" another element, it means that it is immediately on or above the other element, or there may be other elements between them. In contrast, when an element is referred to as being "directly on" another element, there are no other elements between them.

[0011] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted to have a meaning consistent with the relevant technical literature and the currently disclosed content, and are not interpreted in an ideal or very formal sense unless otherwise defined. Moreover, unless otherwise specified, % means % by weight, and 1 ppm is 0.0001% by weight. In the present invention, the term "additionally contain an additional element" means that the additional amount of the additional element is substituted for the remaining iron (Fe). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to exemplary embodiments thereof, so that those skilled in the art will be able to easily practice the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In the present invention, the Si, Al, Mn, Cu, and Cr components that increase the resistivity of non-oriented steel sheet are efficiently controlled, while the In, Sn, Sb, and P components that promote segregation and the Mg component that hinders segregation are also controlled to change the texture, thereby improving both yield strength and core loss.

[0012] The non-oriented electrical steel sheet of the present invention contains, by weight, 2.8-3.8% Si, 0.5-1.5% Al, 0.3-2.0% Mn, 0.01-0.2% Cu, 0.01-0.5% Cr, 0.0005-0.015% In, 0.0050-0.08% Sn, 0.0050-0.05% Sb, 0.0050-0.06% P, and 0.002-0.05% Mg, with the remainder being Fe and unavoidable impurities. First, the reasons for limiting the components of the non-oriented electrical steel sheet will be explained.

[0013] [Si:2.8~3.8wt%] Silicon (Si) must be added in large quantities because it plays a role in increasing the resistivity of the material, lowering iron loss, and ensuring high strength. If too little Si is added, the effect of improving high frequency iron loss cannot be expected, and it is insufficient to ensure strength, and if too much is added, the hardness of the material increases, resulting in inferior productivity and punchability, which is undesirable. Therefore, the Si content can be 2.8 to 3.8% by weight.

[0014] [Al:0.5~1.5wt%] Aluminum (Al) plays a role in increasing the resistivity of the material, lowering iron loss, while at the same time ensuring high strength. If too little Al is added, it is ineffective in reducing high frequency iron loss and ensuring high strength, and fine nitrides may be formed, reducing magnetic properties. Conversely, if too much is added, it may cause problems in changing the physical properties of the mold flux during processes such as steelmaking and continuous casting, significantly reducing productivity. Therefore, Al can be added within the above-mentioned range. More specifically, Al can be included at 0.3 to 2.0 wt%.

[0015] [Mn:0.3~2.0wt%] Manganese (Mn) plays a role in increasing the resistivity of the material, improving core loss, and forming sulfides. If too little Mn is added, fine MnS may precipitate, reducing magnetic properties. Conversely, if too much is added, it may promote the formation of {111} texture, which is detrimental to magnetic properties, reducing magnetic flux density. Therefore, it is preferable to include 0.3 to 2.0 wt% Mn.

[0016] [Cu:0.01~0.2wt%] Copper (Cu) plays a role in forming sulfides together with manganese (Mn). If too little Cu is added, fine CuMnS may precipitate, deteriorating the magnetic properties. Conversely, if too much Cu is added, high temperature brittleness may occur, which may cause cracks to form in the steel sheet during the continuous casting or hot rolling process. Therefore, it is preferable to include 0.01 to 0.2 wt% of Cu.

[0017] [Cr:0.01~0.50wt%] Chromium (Cr) plays a role in increasing the resistivity of the material and reducing iron loss. If the Cr content is too low, there is no effect of increasing the resistivity, and if too much Cr is added, the magnetic flux density decreases, degrading the magnetic properties. Therefore, it is preferable to include 0.01 to 0.50 wt% of Cr.

[0018] [Addition amount of In, Sn, Sb, and P] Indium (In), tin (Sn), antimony (Sb), and phosphorus (P) can be segregated to the grain boundaries by appropriately controlling the annealing conditions. In order to obtain the effect of grain boundary segregation by adding In, Sn, Sb, and P, the concentrations of these components are preferably In: 0.0005-0.015%, Sn: 0.0050-0.08%, Sb: 0.0050-0.05%, and P: 0.0050-0.06%. Below the addition amount range, each of the elements In, Sn, Sb, and P has no grain boundary segregation effect, and above that, it increases the brittleness of the material. Therefore, it is preferable to limit the addition amount within the proposed range.

[0019] [Mg:0.002~0.1wt%] Magnesium (Mg) plays a role in improving iron loss by forming coarse sulfides. If too little Mg is added, it cannot fully fulfill its role and forms fine sulfides, degrading magnetic properties. Conversely, if too much Mg is added, sulfides cannot be formed and residual Mg remains, degrading iron loss. Even if the amount of Mg added is within the range, it may form a compound with the segregated elements and deteriorate the magnetic properties. Therefore, even if the amount of Mg added is within the range of addition, it is preferable to control it so that it is added less than the value of ([In]*[Sn]) / ([Sb]*[P]) as shown in the following [Formula 1]. [Formula 1] [Mg]≦([In]*[Sn]) / ([Sb]*[P])≦Crystal grain size (mm)*20 The meaning of formula 1 is that the amount of segregation elements added is controlled to maximize the segregation effect by appropriately adjusting the amount of elements that promote segregation and the amount of elements that hinder segregation. Therefore, in the case of Mg, since it has the ability to combine with segregation elements to form intermetallic compounds, it is preferable to limit the amount of Mg to the range of [Mg]≦([In]*[Sn]) / ([Sb]*[P]).

[0020] If the amount of Mg added exceeds the range of [Formula 1], the segregation effect is lost and it is difficult to achieve the desired effect of improving magnetic properties and strength. In addition, when grain boundary segregation is formed by the addition of segregation elements, it is affected by the grain size of the steel sheet, i.e., grain size. That is, if the grain size of the steel sheet becomes coarse, the amount of segregation decreases and there is no segregation effect, so it is preferable to control the content of the segregation elements within the range related to the grain size [Equation 1]. In this way, if the grain size grows larger than the relational equation of the amount of segregation elements added according to [Equation 1], it is not easy to expect a segregation effect.

[0021] The non-oriented electrical steel sheet of the present invention may further include one or more of C: 0.0040 or less (0% excluded), S: 0.0040 or less (0% excluded), N: 0.0040 or less (0% excluded), and Ti: 0.0040 or less (0% excluded). When an additional element is further included, it may be included to replace the remaining Fe. Here, C, N, and Ti form carbonitrides and play a role in hindering magnetic domain movement, so it is preferable to limit them within the above ranges, and S forms sulfides and deteriorates grain growth, so for these reasons it is preferable to limit them within the above ranges.

[0022] The non-oriented electrical steel sheet of the present invention may further contain other elements that are unavoidably contained, in addition to the above-mentioned components. The term "unavoidable impurities" refers to impurities that are intentionally added or unavoidably mixed in during the steelmaking and manufacturing process of the non-oriented electrical steel sheet. As inevitable impurities are widely known, a detailed description thereof will be omitted. In addition, the present invention does not exclude the addition of elements other than the above-mentioned alloy components, and various elements may be included within a range that does not harm the technical idea of ​​the present invention. When an additional element is further included, the remaining Fe is replaced with an additional element.

[0023] [Specific resistance: 50 μΩ cm or more] The resistivity of steel sheet is calculated as 13.25 + 11.3 x ([Si] + [Al] + [Mn] / 2 + [Cu] / 2 + [Cr] / 2), where [Si], [Al], [Mn], [Cu], and [Cr] indicate the content (weight %) of Si, Al, Mn, Cu, and Cr, respectively. The higher the resistivity, the lower the iron loss. If the resistivity is too low, the iron loss will be poor and it will be difficult to use it as a high-efficiency motor, and if it is too high, the magnetic flux density may be poor. For use in high-speed motors, the resistivity must be controlled to 50 μΩ·cm or higher.

[0024] [ND / / <114> Percentage: 5% or more The steel sheet of the present invention has a thickness direction (ND) perpendicular to the rolling direction. <114> Fraction of texture in the direction (ND / / <114> The percentage may be 5% or more. The ND / / <114> fraction of the steel sheet is investigated within an allowable error angle of 5° using SEM-EBSD. Since the Young's modulus in this orientation is large in the rolling direction (RD) and the direction perpendicular to the rolling plane (TD), as the proportion of this orientation increases, the yield strength value of Ys(TD±α) becomes larger compared to the yield strength Ys(RD) in the rolling direction. If segregation occurs frequently, the ND / / <114> fraction becomes 5% or more, ensuring the Ys(RD) < Ys(TD±α) characteristic. At this time, the α value ranges from 5 to 90°. [Yield strength: Ys] In the present invention, the yield strength according to each crystal direction of the steel sheet satisfies the following [Equation 2]. [Equation 2] Ys(RD*1.03) ≦ Ys(45°) ≦ Ys(TD) The yield strength of the steel sheet was measured by a tensile test, and the 2% off-set strength was used to eliminate the influence of the strain rate. In [Equation 2], Ys(RD) is the yield strength in the rolling direction, and the value multiplied by the exponent 1.03 here is used as the comparison target, and Ys(TD) is the yield strength in the direction perpendicular to the rolling plane direction. Also, the yield strength inclined 45 degrees from the rolling direction is expressed as Ys(45°). In one embodiment of the present invention, when the yield strength of the steel sheet satisfies the conditions of [Equation 2], the iron loss is also improved.

[0025] Hereinafter, a method for manufacturing a non-oriented electrical steel sheet of the present invention will be described. The method for manufacturing a non-oriented electrical steel sheet of the present invention includes, in the steelmaking process, adding Si: 2.8 to 3.8%, Al: 0.5 to 1.5%, Mn: 0.3 to 2.0%, Cu: 0.01 to 0.2%, Cr: 0.01 to 0.5% by weight to the basic components, and adding In: 0.0005 to 0.015%, Sn: 0.0050 to 0.08%, Sb: 0.0050 to 0.05%, P: 0.0050 to 0.06%, and controlling in the range of Mg: 0.002 to 0.05% to produce a slab, heating the slab, hot rolling the slab to produce a hot-rolled sheet, cold rolling the hot-rolled sheet to produce a cold-rolled sheet, and finally annealing the cold-rolled sheet. The non-oriented electrical steel sheet manufactured by this method satisfies the following [Formula 1]. [Formula 1] [Mg]≦([In]*[Sn]) / ([Sb]*[P])≦Crystal grain size (mm)*20

[0026] Each step will be described in detail below. First, the step of manufacturing the slab will be described. The reasons for limiting the component elements in the slab are the same as those for limiting the composition of the non-oriented electrical steel sheet described above, so repeated explanations will be omitted. The composition of the slab does not substantially change during manufacturing processes such as hot rolling, hot-rolled sheet annealing, cold rolling, and final annealing, which will be described later, so the composition of the slab and the composition of the non-oriented electrical steel sheet are substantially the same. The slab can be heated before manufacturing the hot-rolled sheet. Specifically, the slab is placed in a heating furnace and heated at 1,100 to 1,250°C. When heated to a temperature exceeding 1,250°C, precipitates may be remelted and precipitate finely after hot rolling.

[0027] The heated slab is hot-rolled to 2 to 2.3 mm to produce a hot-rolled sheet. In the stage of producing the hot-rolled sheet, the final finish rolling temperature may be 800° C. or higher. After the step of producing the hot-rolled sheet, the method may further include a step of annealing the hot-rolled sheet. At this time, the annealing temperature of the hot-rolled sheet may be 850 to 1,150°C. If the annealing temperature of the hot-rolled sheet is less than 850°C, the structure does not grow or grows finely, resulting in little increase in magnetic flux density, and if the annealing temperature exceeds 1,150°C, the magnetic properties may rather decrease and the rolling workability may become poor due to deformation of the sheet shape. More specifically, the temperature range may be 950 to 1,125°C. The hot-rolled sheet annealing is performed to increase the orientation favorable to magnetism as necessary, and may be omitted.

[0028] Next, the hot-rolled sheet is pickled and cold-rolled to the desired sheet thickness. Depending on the thickness of the hot-rolled sheet, cold rolling can be performed to a final thickness of 0.2 to 0.65 mm by applying a reduction of 70 to 95%. To match the reduction, cold rolling can be performed once or two or more times with intermediate annealing in between. In the step of producing the cold-rolled sheet, the maximum rolling speed may be 10 m / s or more. The cold-rolled sheet that has been subjected to the final cold rolling undergoes final annealing. During the final annealing stage, the sheet can be soaked at 800~1,000℃. To optimize grain boundary segregation, the lower the annealing temperature, the better, but as the sheet becomes thinner, the annealing temperature must be increased. If the soaking temperature is less than 800℃, recrystallization does not occur sufficiently, and if the final annealing temperature exceeds 1,000℃, the segregation effect is lost. When cooling after soaking, the material may be cooled from the soaking temperature to 700°C at a cooling rate of 10~40°C / s. The cooling rate is controlled within a range in which the grain size does not grow excessively and high frequency core loss does not become inferior. More specifically, the material may be cooled at a rate of 15~35°C / s. Thereafter, the method may further include forming an insulating layer. A method of forming an insulating layer is widely known in the technical field of non-oriented electrical steel sheets, and therefore a detailed description thereof will be omitted.

[0029] Hereinafter, preferred examples and comparative examples of the present invention will be described. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to the following examples. EXAMPLES

[0030] Example 1 A slab with the composition shown in Table 1 below was manufactured. The components were controlled to those shown in Table 1, with the remainder being Fe. The slab was heated to 1,150°C and finish hot rolled at 850°C to produce a hot-rolled sheet with a thickness of 2.0 mm. The hot-rolled sheet was annealed at 1,100°C for 4 minutes and then pickled. Next, the sheet was cold-rolled at a rolling reduction of 87.5% to a thickness of 0.25 mm, and then final annealing was performed at 950°C for 3 minutes. For the non-oriented electrical steel sheets manufactured in this way, the resistivity calculated from the composition of the steel sheets, the grain size measured by the area method, and ND / / <114> The fraction, yield strength in each direction of the texture were measured and are shown in Table 2 below. The texture was measured using SEM-EBSD. The texture tolerance was within 5°, and the yield strength was calculated from the 2% off-set strength.

[0031] [Table 1]

[0032] [Table 2]

[0033] As shown in Tables 1 and 2, the examples that satisfy the alloy components and manufacturing process conditions are ND / / <114> It can be seen that as the fraction of 5% or more deviates from the rolling direction, the yield strength increase rate increases by 3% or more and the core loss is also excellent. On the other hand, steels 4, 10, and 13, which contained more Mg than the calculated value of ([In]*[Sn]) / ([Sb]*[P]), were ND / / <114> It can be seen that the fraction of is 4% or less, the segregation effect is negligible, and therefore the strength improvement effect in each direction is also negligible.

[0034] Steel types 1, 3, 5, and 7 satisfy the condition of [Formula 1] defined in the embodiment of the present invention, and also satisfy the condition of [Formula 2] related to the yield strength in each direction, and the iron loss is sufficiently secured. In addition, the resistivity of steel types 1, 3, 5, and 7 is all 50 μΩ·cm or more, and ND / / <114> The fraction was also found to be more than 5%. However, steel types 2, 4, 6, and 8 to 13, which deviate from the composition range of the present invention or do not satisfy the condition of [Formula 1] even if they are within the composition range, are ND / / <114> It can be confirmed that the fraction is 5% or less, or the yield strength value in each direction of the texture does not satisfy [Equation 2]. The present invention is not limited to the above-mentioned embodiments, and can be manufactured in various different forms, and those skilled in the art will understand that the present invention can be embodied in other specific forms without changing the technical concept or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative and not limiting in all respects.

Claims

1. A non-oriented electrical steel sheet comprising, by weight percent, 2.8-3.8% Si, 0.5-1.5% Al, 0.3-2.0% Mn, 0.01-0.2% Cu, 0.01-0.5% Cr, 0.0005-0.015% In, 0.0050-0.08% Sn, 0.0050-0.05% Sb, 0.0050-0.06% P, and 0.002-0.05% Mg, with the balance being Fe and other unavoidable impurities.

2. 2. The non-oriented electrical steel sheet according to claim 1, wherein the contents of In, Sn, Sb, P, and Mg and the sizes of crystal grains satisfy the relationship of the following [Formula 1]. [Formula 1] [Mg]≦([In]*[Sn]) / ([Sb]*[P])≦crystal grain size (mm)*20

3. C: 0.0040 or less (0% excluded), S: 0.0040 or less (0% excluded), N: 0.0040 or less (0% excluded), and The non-oriented electrical steel sheet according to claim 1, further comprising at least one of the following: Ti: 0.0040 or less (0% excluded).

4. 2. The non-oriented electrical steel sheet according to claim 1, wherein the resistivity of the non-oriented electrical steel sheet is 50 μΩ·cm or more.

5. 2. The non-oriented electrical steel sheet according to claim 1, wherein the non-oriented electrical steel sheet has a ND / / <114> texture fraction of 5% or more.

6. The non-oriented electrical steel sheet according to claim 1, wherein the non-oriented electrical steel sheet satisfies the following crystal direction-specific yield strength relationship [Equation 2]. [Formula 2] Ys(RD*10.3)≦Ys(45°)≦Ys(TD)

7. a step of producing a slab by adding, in weight percent, Si: 2.8-3.8%, Al: 0.5-1.5%, Mn: 0.3-2.0%, Cu: 0.01-0.2%, Cr: 0.01-0.5%, and to the basic components In: 0.0005-0.015%, Sn: 0.0050-0.08%, Sb: 0.0050-0.05%, P: 0.0050-0.06%, and controlling Mg to a range of 0.002-0.05%, a slab heating step of heating the slab; a hot rolling step of subjecting the slab to final finish rolling at a temperature of 800° C. or higher; a hot-rolled sheet annealing step of annealing the hot-rolled sheet; a cold rolling step of rolling the hot rolled sheet at a rolling reduction of 70 to 95%; and and a final annealing step of annealing the cold-rolled sheet at 800 to 1,000°C.

8. 8. The method for producing a non-oriented electrical steel sheet according to claim 7, wherein the contents of In, Sn, Sb, P, and Mg and the size of crystal grains of the non-oriented electrical steel sheet satisfy the following [Formula 1]. [Formula 1] [Mg]≦([In]*[Sn]) / ([Sb]*[P])≦crystal grain size (mm)*20

9. C: 0.0040 or less (0% excluded), S: 0.0040 or less (0% excluded), N: 0.0040 or less (0% excluded), and The method for producing a non-oriented electrical steel sheet according to claim 7, further comprising one or more of the following: Ti: 0.0040 or less (0% excluded).

10. 8. The method for producing a non-oriented electrical steel sheet according to claim 7, wherein the non-oriented electrical steel sheet satisfies at least one of the following conditions related to yield strength [Formula 2]: a resistivity of 50 μΩ cm or more, a fraction of ND / / <114> texture of 5% or more, or [Formula 2] Ys(RD*1.03)≦Ys(45°)≦Ys(TD)

11. The method of claim 7, wherein the slab is heated at a temperature of 1,100 to 1,250°C.

12. The method for manufacturing a non-oriented electrical steel sheet according to claim 7, wherein the hot-rolled sheet annealing step comprises annealing at a temperature of 850 to 1,150°C.

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