Non-oriented electrical steel sheet, motor including same, and method for manufacturing non-oriented electrical steel sheet

Abstract

The present invention provides a non-oriented electrical steel sheet which comprises, in wt%, 2.0 to 3.8% of silicon (Si), 0.8 to 1.5% of aluminum (Al), 0.2 to 0.4% of manganese (Mn), 0 (exclusive) to 0.0080% of carbon (C), 0 (exclusive) to 0.0050% of sulfur (S), 0 (exclusive) to 0.0030% of nitrogen (N), 0 (exclusive) to 0.0050% of titanium (Ti), 0 (exclusive) to 0.015% of phosphorus (P), and a balance of iron (Fe) and other unavoidable impurities, wherein the volume fraction of the texture satisfies Formula 1, below. [Formula 1] (wherein, f{001}<130> is a fraction of {001}<130> in the texture, f{113}<251> is a fraction of {113}<251> in the texture, and f{111}<110> is a fraction of {111}<110> in the texture.

Description

Non-oriented electrical steel sheet, motor including the same, and method for manufacturing non-oriented electrical steel sheet

[0001] The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same.

[0002] Due to policies aimed at reducing carbon dioxide (CO2) emissions to prevent global warming, existing internal combustion engine vehicles are being rapidly replaced by eco-friendly vehicles (hybrid vehicles (HEV), electric vehicles (EV), etc.), particularly electric vehicles (EV).

[0003] Since electric vehicles (EVs) must generate high torque at low speeds or during acceleration, and rotate at high speeds (e.g., 200 Hz or higher) during constant speed and high-speed driving, the non-oriented electrical steel sheets used as the core material for the motor must simultaneously satisfy high magnetic flux density and low iron loss.

[0004] Factors affecting the magnetic properties of these non-oriented electrical steel sheets include chemical composition, sheet thickness, microstructure, insulating coating layer, and texture. Furthermore, these various factors are influenced by the manufacturing process conditions of the non-oriented electrical steel sheets.

[0005] Non-oriented electrical steel sheets are manufactured through the processes of steelmaking / continuous casting, hot rolling, heat treatment after hot rolling, cold rolling, heat treatment after cold rolling, and coating, and non-oriented electrical steel sheets with excellent magnetic properties can be manufactured by optimizing the conditions of each process.

[0006] To reduce iron loss in non-oriented electrical steel sheets, methods such as 1) reducing sheet thickness, 2) increasing resistivity, and 3) improving texture can be used. Among these, improving texture is one of the important factors for improving iron loss and magnetic flux density. For example, the texture of non-oriented electrical steel sheets has a significant impact on magnetic properties.

[0007] The present invention aims to solve various problems, including the problems mentioned above, and provides a non-oriented electrical steel sheet having excellent magnetic properties by having an improved texture, a motor including the same, and a method for manufacturing the non-oriented electrical steel sheet.

[0008] However, these tasks are exemplary and do not limit the scope of the invention.

[0009] According to one aspect of the present invention, a non-oriented electrical steel sheet is provided, comprising, in weight% (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P) 0 to 0.015%, and the remainder being iron (Fe) and other unavoidable impurities, wherein the volume fraction of the texture satisfies Formula 1 below.

[0010] [Equation 1]

[0011]

[0012] (here, f{001} <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.)

[0013] In this embodiment, the texture f{001} of the non-oriented electrical steel sheet <130> The defense ratio can be 23% or more.

[0014] In this embodiment, the texture f{113} of the non-oriented electrical steel sheet <251> The defense ratio can be 20% or more.

[0015] In this embodiment, the texture f{111} of the non-oriented electrical steel sheet <110> The defense share may be less than 23%.

[0016] In this embodiment, the average size of the crystal grains of the non-oriented electrical steel sheet may be 90㎛ to 160㎛.

[0017] In this embodiment, the iron loss (W of the non-oriented electrical steel sheet) 10 / 400 ) may be 12.0W / kg or less.

[0018] In this embodiment, the magnetic flux density (B) of the non-oriented electrical steel sheet 50 ) can be 1.65T or more.

[0019] According to one aspect of the present invention, a method for manufacturing a non-oriented electrical steel sheet comprises: a hot rolling step of hot rolling a slab comprising, in weight% (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P): 0 to 0.015%, and the remainder being iron (Fe) and other unavoidable impurities to produce a hot rolled sheet; and a hot rolling annealing step of hot rolling annealing the hot rolled sheet to produce a hot rolled annealed sheet. A method for manufacturing a non-oriented electrical steel sheet is provided, comprising: a cold rolling step of manufacturing a cold rolled sheet by cold rolling the hot-rolled annealed sheet; and a cold rolling annealing step of manufacturing a cold-rolled annealed sheet by annealing the cold rolled sheet, wherein the speed ratio of the upper roll and the lower roll in the cold rolling step is 1.5 or more and less than 3.0.

[0020] In this embodiment, the friction coefficient between the upper roll and the lower roll in the cold rolling step may be 0.2 or higher.

[0021] In this embodiment, the reduction rate per pass in the cold rolling step may be 25% or more and 50% or less.

[0022] In this embodiment, the iron loss (W of the non-oriented electrical steel sheet)10 / 400 ) may be 12.0W / kg or less.

[0023] In this embodiment, the magnetic flux density (B) of the non-oriented electrical steel sheet 50 ) can be 1.65T or more.

[0024] In this embodiment, the volume fraction of the texture within the non-oriented electrical steel sheet can satisfy the following Equation 1.

[0025] [Equation 1]

[0026]

[0027] (here, f{001} <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.)

[0028] According to one aspect of the present invention, a motor comprising a motor core, wherein the motor core comprises, in weight % (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P): 0 to 0.015%, the remainder being iron (Fe) and unavoidable impurities, and the volume fraction of the texture within the non-oriented electrical steel sheet satisfies the following formula 1.

[0029] [Equation 1]

[0030]

[0031] (here, f{001} <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.)

[0032] In this embodiment, the texture f{001} of the non-oriented electrical steel sheet <130> The defense ratio can be 23% or more.

[0033] In this embodiment, the texture f{113} of the non-oriented electrical steel sheet <251> The defense ratio can be 20% or more.

[0034] In this embodiment, the texture f{111} of the non-oriented electrical steel sheet <110> The defense share may be less than 23%.

[0035] In this embodiment, the average size of the crystal grains of the non-oriented electrical steel sheet may be 90㎛ to 160㎛.

[0036] In this embodiment, the iron loss (W of the non-oriented electrical steel sheet) 10 / 400 ) may be 12.0W / kg or less.

[0037] In this embodiment, the magnetic flux density (B) of the non-oriented electrical steel sheet 50 ) can be 1.65T or more.

[0038] Other aspects, features, and advantages other than those described above will become clear from the following specific details, claims, and drawings for implementing the invention.

[0039] According to one embodiment of the present invention as described above, a non-oriented electrical steel sheet having low surface roughness and a thin coating film to ensure insulation, while simultaneously having low iron loss and high magnetic flux density to produce a motor with a high packing factor, a motor including the same, and a method for manufacturing the same can be provided. Of course, the scope of the present invention is not limited by these effects.

[0040] FIG. 1 is a flowchart schematically illustrating a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention.

[0041] The present invention will be described in detail below. However, in describing the present invention, if it is determined that a detailed description of related known technologies or configurations may unnecessarily obscure the essence of the present invention, such detailed description will be omitted.

[0042] In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component.

[0043] In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0044] In the following embodiments, when various components such as layers, films, regions, and plates are described as being "on" another component, this includes not only cases where they are "directly on" another component, but also cases where another component is interposed between them.

[0045] In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and therefore the present invention is not necessarily limited to what is illustrated.

[0046] In the following embodiments, terms such as "include" or "have" mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added.

[0047] In this specification, "A and / or B" indicates the case where it is A, B, or both A and B. Additionally, in this specification, "at least one of A and B" indicates the case where it is A, B, or both A and B.

[0048] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0049] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0050] FIG. 1 is a flowchart schematically illustrating a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention.

[0051] Referring to FIG. 1, a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention may include a hot rolling step (S100), a pre-annealing step (S200), a cold rolling step (S300), a cold rolling annealing step (S400), and a coating step (S500).

[0052] In a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention, the semi-finished product subject to hot rolling may be a slab. The slab in the semi-finished product state can be obtained through a continuous casting process after obtaining molten steel of a predetermined composition through a steelmaking process.

[0053] First, the slab can be manufactured through a continuous casting process. The slab may contain silicon (Si), manganese (Mn), aluminum (Al), the remainder being iron (Fe), and unavoidable impurities. Additionally, the slab may further contain carbon (C), sulfur (S), nitrogen (N), titanium (Ti), and phosphorus (P). In this case, carbon (C), sulfur (S), nitrogen (N), titanium (Ti), and phosphorus (P) may correspond to impurity elements.

[0054] In one embodiment, the slab may comprise, in weight% (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P): 0 to 0.015%, and the remainder being iron (Fe) and other unavoidable impurities.

[0055] The following explains the reason why the numerical range of components included in non-oriented electrical steel sheets is limited.

[0056] Carbon (C)

[0057] Since carbon can increase iron loss by forming carbides such as TiC and NbC, it must be contained in the slab in an appropriate amount. The carbon content in the slab may be 0 (greater than) to 0.0080 weight%. If the carbon content in the slab exceeds 0.0080 weight%, magnetic aging may occur, which may degrade magnetic properties.

[0058] Silicon (Si)

[0059] Silicon is a major additive element that can lower iron loss by increasing resistivity. The silicon content in the slab may be 2.0 wt% to 3.8 wt%. If the silicon content in the slab is less than 2.0 wt%, it may be difficult to obtain a sufficient iron loss improvement effect. If the silicon content in the slab exceeds 3.8 wt%, the brittleness of the material increases, which may cause plate breakage during coiling and cold rolling, leading to a sharp decrease in rolling productivity and a decline in punchability, which may increase the difficulty of the production process. In addition, permeability and magnetic flux density may decrease.

[0060] Manganese (Mn)

[0061] Manganese, together with silicon, can increase resistivity, thereby lowering iron loss and improving texture. The manganese content in the slab may be 0.2 wt% to 0.4 wt%. If the manganese content in the slab is less than 0.2 wt%, fine MnS precipitates may form, inhibiting grain growth and potentially degrading magnetic properties such as reduced magnetic flux density. If the manganese content in the slab exceeds 0.4 wt%, excessive precipitation of MnS may occur, promoting the formation of a texture unfavorable to magnetism, which may lead to a rapid decrease in magnetic flux density and a decrease in cold rolling performance.

[0062] Aluminum (Al)

[0063] Aluminum can increase resistivity together with silicon to lower iron loss. Aluminum can combine with nitrogen to form AlN precipitates. The aluminum content in the slab may be 0.8 wt% to 1.5 wt%. If the aluminum content in the slab is less than 0.8 wt%, a sufficient effect of increasing resistivity cannot be obtained, and iron loss may increase. If the aluminum content in the slab exceeds 1.5 wt%, a decrease in cold rolling performance may occur, and AlN may form on the surface during cold rolling annealing, increasing iron loss and decreasing magnetic flux density, which may lead to deterioration of magnetic properties.

[0064] Yellow (S)

[0065] Sulfur forms precipitates such as MnS and CuS, which inhibit grain growth and increase iron loss, so it is desirable to add it in low amounts. The sulfur content in the slab may be 0 (greater than) to 0.0050 weight%. If the sulfur content in the slab exceeds 0.0050 weight%, magnetic properties may deteriorate due to increased sulfide formation.

[0066] Nitrogen (N)

[0067] Nitrogen combines with Al, Ti, Nb, etc. to form precipitates such as AiN, TiN, and NbN, which inhibit grain growth and increase iron loss; therefore, it is desirable to add it in low amounts. The nitrogen content in the slab may be 0 (greater) weight% to 0.0030 weight%. If the nitrogen content in the slab exceeds 0.0030 weight%, magnetic properties may deteriorate due to increased nitride formation.

[0068] Titanium (Ti)

[0069] Titanium is an element with a very strong tendency to form precipitates in steel. It combines with C and N to form fine precipitates such as TiC and TiN, which inhibit grain growth and increase iron loss; therefore, it is desirable to add it in low amounts. The titanium content in the slab may be 0 (greater than) to 0.0050 weight%. If the titanium content in the slab exceeds 0.0050 weight%, magnetic properties may deteriorate due to increased formation of carbides and nitrides.

[0070] Ph(P)

[0071] Phosphorus is a grain boundary segregation element that develops texture. The phosphorus content in the slab may be 0 (greater than) to 0.015 weight%. If the phosphorus content in the slab exceeds 0.015 weight%, the segregation effect may inhibit grain growth, degrade magnetic properties, and reduce cold rolling performance.

[0072] It will be understood by anyone with ordinary knowledge in the technical field to which this invention pertains that, in addition to the components described above, various components included in non-oriented electrical steel sheets may be included as components of the non-oriented electrical steel sheet of this invention. Combinations of commonly known components and their applications naturally fall within the scope of the rights of this invention.

[0073] Hot rolling step (S100)

[0074] In the hot rolling step (S100), the above-mentioned slab can be hot-rolled to produce a hot-rolled plate.

[0075] The hot rolling step (S100) may include a step of reheating the slab, a step of rolling the reheated slab, and a step of winding the rolled slab.

[0076] First, the slab may be reheated in the hot rolling step (S100). If the slab reheating temperature (SRT) is too high, precipitates such as carbon (C), sulfur (S), and nitrogen (N) (e.g., AlN) within the slab may be redissolved, and fine precipitates may be formed during subsequent rolling and annealing steps, which may inhibit grain growth and degrade magnetic properties. If the slab reheating temperature is too low, the rolling load increases during hot rolling, which may reduce rollability. The slab reheating temperature in the hot rolling step (S100) according to one embodiment may be 1,000°C to 1,200°C.

[0077] After reheating the slab, the heated slab can be rolled at a predetermined finishing delivery temperature (FDT). The finishing delivery temperature of the hot rolling step (S100) may be 800°C to 1,000°C. When rolling at the finishing delivery temperature, material variation of the electrical steel sheet is prevented, and an electrical steel sheet with excellent mechanical and magnetic properties can be manufactured.

[0078] After rolling the slab at a predetermined finishing rolling temperature, it can be cooled to a predetermined coiling temperature (CT) and coiled. According to one embodiment, the coiling temperature may be 550°C to 650°C. If the coiling temperature is less than 550°C, the brittleness of the steel plate increases, and plate breakage may occur during coiling. If the coiling temperature exceeds 650°C, fine AlN may be formed during cooling after coiling, which may increase iron loss.

[0079] In one embodiment of the present invention, the thickness of the hot-rolled plate after hot rolling may be 1.8 mm to 2.6 mm. At this time, if the thickness of the hot-rolled plate exceeds 2.6 mm, the cold rolling reduction rate increases, so the texture of the final product may deteriorate.

[0080] Preliminary annealing step (S200)

[0081] A preliminary annealing step (S200) may be performed after the hot rolling step (S100). However, the present invention is not limited thereto. The preliminary annealing step (S200) may be omitted. In this case, a cold rolling step (S300) may be performed after the hot rolling step (S100).

[0082] In the preliminary annealing step (S200), a pre-annealed plate can be manufactured by hot-rolling and annealing a coiled and cooled hot-rolled plate.

[0083] The preliminary annealing step (S200) may include the steps of raising the temperature of the hot-rolled plate to a predetermined annealing temperature, annealing at a predetermined annealing temperature, cooling the annealed hot-rolled plate, and performing shot blasting and pickling. Through the preliminary annealing step (S200), the uniformity of the microstructure and cold rolling performance of the hot-rolled plate can be ensured.

[0084] In the pre-annealing step (S200), the hot-rolled plate can be heated (or increased) to the pre-annealing temperature at a heating rate of 20℃ / s or more, preferably 20℃ / s to 40℃ / s. At this time, if the heating rate is less than 20℃ / s, productivity may decrease and the manufacturing cost may increase. On the other hand, if the heating rate exceeds 40℃ / s, non-uniform grain growth may occur, which may result in a decrease in the magnetic properties of the final product.

[0085] In the preliminary annealing step (S200), the hot-rolled plate heated at the aforementioned heating rate can be annealed at an annealing temperature of 900°C to 1,050°C for a period of 30 seconds to 120 seconds. At this time, if the annealing temperature of the preliminary annealing step (S200) is too low, the cast structure elongated after hot rolling remains, causing microstructural non-uniformity and forming small grains, which may reduce cold rolling performance. On the other hand, if the annealing temperature of the preliminary annealing step (S200) is too high, the grains grow excessively, the grain size variation increases, and an imbalance in the texture of the final product may occur, and anisotropy may develop.

[0086] In the preliminary annealing step (S200), the hot-rolled plate, which has been heated at the above-mentioned heating rate and then annealed at the above-mentioned annealing temperature, can be cooled at a cooling rate of 30℃ / s or more, preferably 30℃ / s or more and 50℃ / s or less. If the cooling rate is less than 30℃ / s, productivity may decrease and manufacturing costs may increase. On the other hand, if the cooling rate exceeds 50℃ / s, thermal stress may accumulate inside the hot-rolled plate during the cooling process, increasing the likelihood of plate breakage during cold rolling.

[0087] After heating, annealing, and cooling the hot-rolled plate in the preliminary annealing step (S200), the hot-rolled plate may undergo a shot blast process before cold rolling. The shot blast process is a process of removing scale formed on the surface of the hot-rolled plate by applying physical force to the hot-rolled plate; more specifically, metal grit may be sprayed onto the surface of the hot-rolled plate to destroy and remove the scale formed on the surface of the hot-rolled plate after hot rolling.

[0088] A pickling process may be additionally performed after the shot blasting process. In the pickling process, the oxide layer formed on the surface of the hot-rolled plate can be removed using a pickling solution.

[0089] Cold rolling step (S300)

[0090] A cold rolling step (S300) may be performed after a preliminary annealing step (S200). In the cold rolling step (S300), a pre-annealed plate that has been hot-rolled and annealed may be cold-rolled to produce a cold-rolled plate. In the cold rolling step (S300), the pre-annealed plate may be cold-rolled to a thickness of 0.35 mm or less, more preferably 0.15 mm to 0.35 mm. In one embodiment, to impart rollability, the plate temperature (e.g., the temperature of the pre-annealed plate) may be raised and hot rolling may be performed.

[0091] The reduction rate in the cold rolling step (S300) may be 80% to 90%. When cold rolling is performed under the above conditions, the mechanical properties and magnetic properties of the final product may be excellent.

[0092] After cold rolling, the cold-rolled grain size can be about 80㎛ to 160㎛.

[0093] Meanwhile, the inventors of this specification have confirmed that the texture of the steel sheet can be optimized according to the rolling conditions in the cold rolling step (S300). In non-oriented electrical steel sheets (or slabs), the texture can serve as an important factor for improving iron loss and magnetic flux density.

[0094] Specifically, in terms of the texture of a non-oriented electrical steel sheet (or slab) comprising, in weight% (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P): 0 to 0.015%, and the remainder being iron (Fe) and other unavoidable impurities, {001} <130> and {113} <251> is easily magnetized, and {111} <110> ...is disadvantageous to magnetization. Therefore, among the collective organizations {001} <130> and {113} <251> is less, {111} <110> The more of it is present, the higher the magnetic flux density and the lower the iron loss. Due to this crystalline magnetic anisotropy, the magnetic flux density and iron loss in non-oriented electrical steel sheets depend greatly on the texture.

[0095] In one embodiment, the friction coefficient of the upper work roll and the friction coefficient of the lower work roll in the cold rolling step (S300) may each be 0.2 or higher (hereinafter, first rolling condition). When the friction coefficient of the upper work roll and the friction coefficient of the lower work roll in the cold rolling step (S300) are each 0.2 or higher, the fraction of a texture advantageous to magnetism during rolling is increased, thereby enabling the production of a non-oriented electrical steel sheet with excellent magnetic properties. When the friction coefficient of the upper work roll and the friction coefficient of the lower work roll in the cold rolling step (S300) are each less than 0.2, a texture advantageous to magnetism of the steel sheet may not be sufficiently formed.

[0096] Additionally, in the cold rolling step (S300), the friction coefficient of one of the upper work roll and the lower work roll may be 0.2 or higher. That is, the friction coefficient of the upper work roll may be 0.2 or higher, and the friction coefficient of the lower work roll may be less than 0.2. Alternatively, the friction coefficient of the lower work roll may be 0.2 or higher, and the friction coefficient of the upper work roll may be less than 0.2. However, even in this case, the ratio of the friction coefficients of the upper work roll and the lower work roll may be less than 4 times. If the ratio of the friction coefficients of the upper work roll and the lower work roll differs by 4 times or more, slip may occur between the plate and the work roll, and there may be a problem of surface defects occurring during cold rolling.

[0097] At this time, the friction coefficient between the upper work roll and the lower work roll can be measured in various ways known in the industry. For example, the friction coefficient between the upper work roll and the lower work roll may be measured using torque and rolling load, or it may be measured by back-calculating rolling performance data using rolling speed. Alternatively, the friction coefficient may be measured without using rolling load, in which case it may be measured using the torque, rotational speed, and radius of the work roll.

[0098] In one embodiment, the speed ratio of the upper work roll and the lower work roll in the cold rolling step (S300) may be 1.5 or higher and less than 3.0 (hereinafter referred to as the second rolling condition). This means that the speeds of the upper work roll and the lower work roll may differ from each other during cold rolling. For example, the speed of the upper work roll may be faster than the speed of the lower work roll. Alternatively, the speed of the lower work roll may be faster than the speed of the upper work roll. In this case, if the speed ratio of the upper work roll and the lower work roll is less than 1.5, sufficient shear deformation may not occur during rolling, and the texture may deteriorate. Additionally, if the speed ratio of the upper work roll and the lower work roll exceeds 3.0, material feeding is impossible during rolling, so it is preferable that the speed ratio of the upper work roll and the lower work roll be 3.0 or lower.

[0099] In this case, the speed ratio of the upper work roll and the lower work roll can be controlled by adjusting the reduction gear ratio of the cold rolling equipment. However, the method of controlling the speed ratio of the upper work roll and the lower work roll is not limited to this, and various methods of controlling the speeds of the upper work roll and the lower work roll can be utilized.

[0100] In one embodiment, the reduction rate per pass in the cold rolling step (S300) may be 25% or more and 50% or less (hereinafter, third rolling condition). If the reduction rate per pass during cold rolling is less than 25%, a texture favorable to magnetism may not be sufficiently formed, and if the reduction rate per pass during cold rolling exceeds 50%, it may cause plate breakage and cracks in the edge portions, making rolling impossible; therefore, it is preferable that the reduction rate per pass be 50% or less.

[0101] At this time, the reduction rate per pass can be determined by measuring the thickness before cold rolling and the thickness after cold rolling, and comparing them.

[0102] The rolled texture with plane deformation during cold rolling is generally {001} <130> A strong α-fiber texture where maximum strength is obtained and {111} <110> It develops into a weak Y-fiber texture composed of orientations. In a plane-deformed texture, when the plate temperature rises and recrystallization occurs, {111} <110> A texture composed of orientations close to is primarily developed, and the stronger the plane strain, the more {111} recrystallizes <110> The orientation develops strongly. On the other hand, the rolled texture shear-deformed during cold rolling develops α-fiber texture and GOSS texture. As such, when the shear-deformed texture recrystallizes as the plate temperature rises, {001} <130> The direction develops, and as a result, relatively {111} <110> Since a small orientation fraction is formed, a texture favorable to magnetism can be formed.

[0103] Accordingly, in a manufacturing method according to one embodiment of the present invention, by presenting optimal rolling conditions in the cold rolling step (S300), the fraction of a texture having a structure favorable to magnetism in the cold rolling step (S300) can be improved. As described above, first to third rolling conditions are presented in the cold rolling step (S300). In one embodiment, when two or more of the first to third rolling conditions are satisfied, a non-oriented electrical steel sheet having excellent magnetic properties in which iron loss and magnetic flux density satisfy the range of the present invention can be manufactured.

[0104] Cold rolling annealing stage (S400)

[0105] After the cold rolling step (S300), a cold rolling annealing step (S400) may be performed. At this time, the cold rolling annealing step (S400) may be referred to as the final annealing step. In the cold rolling annealing step (S400), a cold rolling annealed plate may be manufactured by cold rolling annealing the cold rolling plate. The cold rolling annealing step (S400) may be omitted depending on the characteristic requirements of the final product and the step conditions.

[0106] The cold rolling annealing step (S400) can be performed at a temperature that derives the optimal grain size by considering the final magnetic and mechanical properties.

[0107] In one embodiment, the cold rolling annealing step (S400) may include the step of heating the cold rolled plate to an annealing temperature of 900°C to 1,100°C at a heating rate of 10°C / s or more, the step of maintaining it for 5 seconds to 70 seconds, and the step of cooling the annealed cold rolled plate at a cooling rate of 20°C / s or more, preferably 20°C / s or more and 50°C / s or less.

[0108] If the cold rolling annealing temperature in the cold rolling annealing step (S400) is less than 900°C, the grain size is fine, which may increase hysteresis loss and increase the area fraction of a texture unfavorable to magnetism in the final product. On the other hand, if the cold rolling annealing temperature exceeds 1,100°C, the grain size becomes coarse, which may increase eddy current loss. Additionally, if the holding time is less than 5 seconds, grain growth does not occur sufficiently, which may increase hysteresis loss. On the other hand, if the holding time exceeds 70 seconds, productivity decreases, which may increase manufacturing costs.

[0109] The cold rolling annealing step (S400) may be performed in an atmosphere containing a mixed gas to prevent excessive oxidation and nitriding of the surface. By performing the cold rolling annealing step (S400) in an atmosphere containing a mixed gas, a cold rolling annealed plate with excellent surface condition can be obtained. In one embodiment, the cold rolling annealing step (S400) may be performed in an atmosphere containing a mixed gas consisting of hydrogen (H2), nitrogen (N2), and residual oxygen (O2). For example, the cold rolling annealing may be performed in an atmosphere of 30% hydrogen (H2) and 70% nitrogen (N2).

[0110] Coating step (S500)

[0111] A coating step (S500) may be performed after the cold-rolled annealing step (S400). In the coating step (S500), a coating layer may be formed on the surface of the cold-rolled annealed plate. The formation of the coating layer may be performed by a method well known to a person skilled in the art. For example, it may be performed by applying or spraying a composition for the coating layer onto one or both sides of the steel plate. By forming a coating layer through the coating step (S500), the stampability of the final product can be improved and insulation properties can be secured.

[0112] As described above, a non-oriented electrical steel sheet can be manufactured by forming a coating layer on the surface of a cold-rolled annealed sheet.

[0113] Non-oriented electrical steel sheets

[0114] A non-oriented electrical steel sheet according to one embodiment of the present invention can be manufactured by the method for manufacturing a non-oriented electrical steel sheet described above.

[0115] The non-oriented electrical steel sheet produced by the above-described manufacturing method may contain silicon (Si), manganese (Mn), aluminum (Al), carbon (C), sulfur (S), nitrogen (N), titanium (Ti), phosphorus (P), the remainder being iron (Fe) and unavoidable impurities.

[0116] Specifically, the non-oriented electrical steel sheet may contain, in weight% (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P): 0 to 0.015%, the remainder being iron (Fe) and unavoidable impurities.

[0117] In one embodiment, the non-oriented electrical steel sheet may have a grain size of 90 μm or more and 160 μm or less.

[0118] In one embodiment, the iron loss (W of a non-oriented electrical steel sheet)10 / 400 ) may be 12.0 W / kg or less. Specifically, the iron loss (W of non-oriented electrical steel) 10 / 400 ) may be 8.0 W / kg or more and 12.0 W / kg or less.

[0119] In one embodiment, magnetic flux density B of a non-oriented electrical steel sheet 50 It can be 1.65T or more.

[0120] A non-oriented electrical steel sheet (or slab) according to one embodiment of the present invention has a texture favorable to magnetism {001} by controlling the rolling conditions during cold rolling. <130> and {113} <251> The fraction of increases, and the texture unfavorable to magnetism {111} <110> It was confirmed that the magnetic properties of non-oriented electrical steel sheets are improved as the fraction of [the component] decreases.

[0121] In addition, in the texture of non-oriented electrical steel sheets, {001} <130> fraction of, {113} <251> fraction of and {111} <110> It was confirmed that when the fraction satisfies [Equation 1] below, the non-oriented electrical steel sheet has low iron loss and high magnetic flux density.

[0122] [Equation 1]

[0123]

[0124] f{001} in [Equation 1] <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.

[0125] A non-oriented electrical steel sheet according to one embodiment of the present invention can satisfy [Equation 1] when two or more of the first to third rolling conditions are satisfied during the cold rolling stage of manufacturing. When two or more of the first to third rolling conditions are satisfied during the cold rolling stage, shear deformation is applied to all thickness layers of the steel sheet, so the effect of improving the texture can be obtained, thereby satisfying [Equation 1]. That is, when two or more of the first to third rolling conditions are satisfied during the cold rolling stage, among the textures of the manufactured non-oriented electrical steel sheet, a texture favorable to magnetism {001} <130> and {113} <251> The fraction of can increase, and the texture is unfavorable to magnetism {111} <110> The fraction of may decrease.

[0126] Specifically, the orientation fraction f{001} of the texture of a non-oriented electrical steel sheet manufactured by satisfying two or more of the first to third rolling conditions in the cold rolling stage. <130> It can be 23% or more. In addition, the orientation fraction f{113} of the texture of non-oriented electrical steel sheets <251> It can be 20% or more. In addition, the orientation fraction f{111} of the texture of the oriented electrical steel sheet <110> It may be less than 23%.

[0127] {001} in the texture of non-oriented electrical steel sheets <130> fraction of, {113} <251> fraction of and {111} <110> When the fraction satisfies [Equation 1], the manufactured non-oriented electrical steel sheet can possess excellent magnetic properties. That is, {001}, a texture favorable for magnetism <130> fraction of and {113} <251> {111}, a collective organization that is unfavorable to magnetism, where the sum of the fractions is <110> When the fraction is greater than, the manufactured non-oriented electrical steel sheet has an iron loss (W) of 12.0 W / kg or less 10 / 100 ) and magnetic flux density of 1.65T or higher (B 50It may have ). When the value of [Equation 1] is 1.9 or less, the magnetic properties of the manufactured non-oriented electrical steel sheet may be inferior because the fraction of the texture favorable to magnetism is small and the fraction of the texture unfavorable to magnetism is large.

[0128] Non-oriented electrical steel sheet and motor including the same

[0129] A motor core manufactured by a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention may comprise, in weight % (wt%), a non-oriented electrical steel sheet comprising silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 (greater) to 0.0080%, sulfur (S): 0 (greater) to 0.0050%, nitrogen (N): 0 (greater) to 0.0030%, titanium (Ti): 0 (greater) to 0.0050%, phosphorus (P): 0 (greater) to 0.015%, and the remainder being iron (Fe) and other unavoidable impurities.

[0130] A motor according to one embodiment of the present invention may include a motor core, and the motor core may be formed by stamping and laminating non-oriented electrical steel sheets into a predetermined shape. That is, a motor according to one embodiment of the present invention may include such non-oriented electrical steel sheets. In other words, a motor core may be manufactured by laminating such non-oriented electrical steel sheets, and a motor may be manufactured using such a motor core.

[0131] In one embodiment, the non-oriented electrical steel sheet may comprise a base material and a coating layer formed on the surface of the base material. The coating layer may be formed on one or both sides of the base material. Here, the base material may be a substrate steel sheet.

[0132] In one embodiment, the non-oriented electrical steel sheet included in the motor may satisfy the following [Equation 1] in terms of texture.

[0133] [Equation 1]

[0134]

[0135] f{001} in [Equation 1] <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.

[0136] Non-oriented electrical steel sheets can provide non-oriented electrical steel sheets with excellent magnetic properties by satisfying [Equation 1] regarding the fraction of the texture. That is, {001}, which is a texture favorable to magnetism <130> fraction of and {113} <251> {111}, a collective organization that is unfavorable to magnetism, where the sum of the fractions is <110> In cases where the fraction is greater than, non-oriented electrical steel sheets have iron loss (W) of 12.0 W / kg or less 10 / 400 ) and magnetic flux density of 1.65 T or greater (B 50 Can have ).

[0137] In one embodiment, the packing density of the motor core may be 96% or higher. A motor including a motor core manufactured in this way may have excellent magnetic properties and high efficiency.

[0138] Methods for measuring physical properties

[0139] Hereinafter, a measurement method for measuring the physical properties of a non-oriented electrical steel sheet according to one embodiment of the present invention is described.

[0140] [Measurement of Collective Tissue Volume Fraction]

[0141] {100} with a deviation angle of 15 degrees or less based on EBSD (Electron Backscattered Diffraction) analysis <130> The orientation fraction was measured. Specifically, after mechanical polishing and / or chemical polishing were performed on each specimen, an area of ​​1 cm x 1 cm on the ND plane at the 1 / 4 thickness position was measured using EBSD under an electron beam step size of 10 µm. At this time, the fraction was calculated after measuring at least 5,000 grains during texture measurement.

[0142] [Grain Size Measurement]

[0143] The grain size was measured by distinguishing the grains based on the point where the deviation angle between neighboring grains was 10 degrees or more through EBSD measurement.

[0144] [Iron loss, magnetic flux density measurement]

[0145] Magnetic properties were determined by measuring iron loss and magnetic flux density values ​​in the L direction (i.e., parallel to the rolling direction) and C direction (i.e., perpendicular to the rolling direction) using a single sheet tester (SST) and calculating the average value. Specifically, for a specimen measuring 60 mm x 60 mm, measurements were taken twice in the L direction and twice in the C direction for a total of four measurements, and the average value was calculated. The specimen was manufactured by punching using a 60 mm x 60 mm punching die. The iron loss was measured at 50 Hz and 1.5 T, and the magnetic flux density is the magnetic flux density at 5000 A / m.

[0146] Experimental Example

[0147] The present invention will be explained in more detail below through experimental examples. However, the following experimental examples are intended to explain the present invention more specifically, and the scope of the present invention is not limited by the following experimental examples. The following experimental examples may be appropriately modified or changed by those skilled in the art within the scope of the present invention.

[0148] Each example and comparative example was prepared by the following method.

[0149] (1) A slab was prepared containing, in weight percent, 3.3% silicon (Si), 0.302% manganese (Mn), 0.903% aluminum (Al), 0.007% carbon (C), 0.0018% sulfur (S), 0.0012% nitrogen (N), 0.0013% titanium (Ti), 0.01% phosphorus (P), and the remainder being iron (Fe) and unavoidable impurities.

[0150] (2) In the hot rolling stage, the slab was reheated to a temperature of 1,130 ℃, finished rolled at a finishing rolling temperature of 900 ℃, and coiled at a temperature of 580 ℃. At this time, the thickness of the hot-rolled plate was 2.0 mm.

[0151] (3) In the pre-annealing step, the hot-rolled plate was pre-annealed at 1000°C for 90 seconds, and then shot blasting and pickling processes were performed sequentially.

[0152] (4) In the cold rolling stage, the pre-annealed plate was cold-rolled to make a cold-rolled plate with a thickness of 0.25 mm.

[0153] At this time, during the cold rolling stage, the friction coefficients of the upper work roll and the lower work roll were set to one of 0.06, 0.1, 0.2, or 0.3 (i.e., the first rolling condition).

[0154] In addition, during the cold rolling stage, the speed ratio of the upper work roll to the lower work roll was set to one of 1.0, 1.5, or 2.0 (i.e., second rolling condition).

[0155] In addition, during the cold rolling stage, the reduction rate per pass was set to one of 15%, 25%, or 35%. (i.e., third rolling condition)

[0156] (5) In the cold rolling annealing stage, the cold-rolled plate was heated to 1000°C at a heating rate of 20°C / s and maintained for 45 seconds. After that, it was cooled.

[0157] The non-oriented electrical steel sheet according to one embodiment of the present invention, manufactured through the above manufacturing method, evaluated whether it satisfied at least two of the first to third rolling conditions during the cold rolling step, and whether it satisfied [Equation 1] with respect to the fraction of the texture.

[0158] [Equation 1]

[0159]

[0160] f{001} in [Equation 1] <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.

[0161] In a cold rolling step, the friction coefficient of the upper work roll and the friction coefficient of the lower work roll are each 0.2 or higher (i.e., first rolling condition), the speed ratio of the upper work roll and the lower work roll is 1.5 or higher and less than 3.0 (i.e., second rolling condition), and the reduction rate per pass per pass may be 25% or higher and 50% or lower (i.e., first rolling condition). When two or more of the first to third rolling conditions are satisfied, the non-oriented electrical steel sheet may satisfy the value of [Equation 1] regarding the fraction of the texture. That is, when two or more of the first to third rolling conditions are satisfied in the cold rolling step, the texture of the non-oriented electrical steel sheet that is favorable to magnetism {001} <130> and {113} <251> The fraction of may increase, and {111} unfavorable to magnetism <110> The fraction of may decrease.

[0162]

[0163] Classification Roll Speed ​​Non-friction Coefficient 1 Reduction Rate per Pass {001} <130> {113} <251> {111} <110> Equation 1 Iron Loss Magnetic Flux Density Example 1 1.00.225 23.220.122.11.96 10.98 1.66 Example 2 1.00.235 23.520.821.62.05 10.89 1.66 Example 3 1.00.325 24.822.422.52.10 10.78 1.67 Example 4 1.00.335 24.621.522.52.05 10.71.66 Example 5 1.50.0625 25.820.820.12.32 10.67 1.67 Example 6 1.50.0635 23.221.815.12.98 10.67 1.66 Example 7 1. 50.12525.721.822.82.0810.581.67 Example 81.50.13528.321.214.33.4610.431.67 Example 91.50.21526.122.915.83.1010.551.66 Example 101.50.22533.430.19.26.9010.081.67 Example 111.50.31524.123.814.23.3710.341.66 Example 122.00.062528.225.311.84.5310.021.68 Example 132.00.063533.8 25.9 11.5 5.1 99.9 91.68 Example 14 2.00.1 25 30.1 28.8 5.1 11.5 59.7 51.68 Example 15 2.00.1 35 32.3 27.3 8.5 7.0 19.1 1.69 Example 16 2.00.2 15 33.7 25.8 10.2 5.8 39.3 51.68 Example 17 2.00.2 25 34.8 30.2 4.5 14.4 48.5 81.69 Example 18 2.00.3 15 35.8 29.3 7.6 8.5 78.8 71.69 Comparative Example 1 1.00.0 6 15 13.3 13.5 37.5 0.7 11 4.49 1.62 Comparative Example 2 1.00.06 25 15.6 14.3 34.20.8 7 14.48 1.59 Comparative Example 3 1.00.06 35 16.7 15.2 30.11.06 13.35 1.64 Comparative Example 4 1.00.1 15 16.2 15.7 35.20.9 113.8 21.64 Comparative Example 5 1.00.1 25 20.5 16.5 31.11.1 9 13.2 11.64 Comparative Example 6 1.00.1 35 19.3 18.5 28.21.34 13.1 11.63 Comparative Example 7 1.00.2 15 25.8 20.7 25.3 1.8 4 13.1 21.64 Comparative Example 8 1.00.31518.22123.21.6913.081.64 Comparative Example 91.50.061521.520.826.31.6113.051.63 Comparative Example 101.50.11522.321.525.31.7312.981.65 Comparative Example 112.00.061524.120.124.31.8212.651.65 Comparative Example 122.00.11525.820.725.31.8412.321.65.

[0164] Referring to Table 1, Comparative Examples 1 to 12 did not satisfy two or more of the first to third rolling conditions during the cold rolling stage. Comparative Examples 1 and 4 did not satisfy all of the first to third rolling conditions during the cold rolling stage, and the other Comparative Examples satisfied only one of the first to third rolling conditions.

[0165] Specifically, Comparative Examples 2, 3, 5, and 6 satisfied the scope of the present invention with respect to the third rolling condition (i.e., reduction rate per pass), but did not satisfy the scope of the present invention with respect to the first rolling condition (i.e., friction coefficient) and the second rolling condition (i.e., roll speed ratio). As a result, Comparative Examples 2, 3, 5, and 6 did not satisfy the scope of the present invention as the value of Equation 1 was 1.9 or less, and iron loss (W 10 / 400 The value of ) exceeds 12.0 W / kg and the magnetic flux density (B 50 It was found that ) was smaller than 1.65T. Therefore, it can be confirmed that Comparative Examples 2, 3, 5, and 6 have inferior magnetic properties by failing to satisfy the value of Equation 1.

[0166] Comparative Examples 7 and 8 satisfied the scope of the present invention with respect to the first rolling condition (i.e., friction coefficient), but did not satisfy the scope of the present invention with respect to the second rolling condition (i.e., roll speed ratio) and the third rolling condition (i.e., reduction rate per pass). As a result, Comparative Examples 7 and 8 did not satisfy the scope of the present invention, as the value of Equation 1 was 1.9 or less, and iron loss (W10 / 400 The value of ) exceeds 12.0 W / kg and the magnetic flux density (B 50 It was found that ) was smaller than 1.65T. Therefore, it can be confirmed that Comparative Examples 7 and 8 have inferior magnetic properties by failing to satisfy the value of Equation 1.

[0167] Comparative Examples 9 to 12 satisfied the scope of the present invention with respect to the second rolling condition (i.e., roll speed ratio), but did not satisfy the scope of the present invention with respect to the first rolling condition (i.e., friction coefficient) and the third rolling condition (i.e., reduction rate per pass). As a result, Comparative Examples 9 to 12 did not satisfy the scope of the present invention, as the value of Equation 1 was 1.9 or less, and iron loss (W 10 / 400 The value of ) exceeds 12.0 W / kg and the magnetic flux density (B 50 It was found that ) was smaller than 1.65T. Therefore, it can be confirmed that Comparative Examples 9 to 12 have inferior magnetic properties by failing to satisfy the value of Equation 1.

[0168] On the other hand, Examples 1 to 18 according to the present invention satisfied two or more of the first to third rolling conditions in the cold rolling step. Example 17 satisfied all three of the first to third rolling conditions in the cold rolling step, and other examples satisfied two or more of the first to third rolling conditions.

[0169] Specifically, Examples 1 to 4 did not satisfy the scope of the present invention with respect to the second rolling condition (i.e., roll speed ratio), but satisfied the scope of the present invention with respect to the first rolling condition (i.e., friction coefficient) and the third rolling condition (i.e., reduction rate per pass). As a result, Examples 1 to 4 satisfied the scope of the present invention with the value of Equation 1 being greater than 1.9, and iron loss (W 10 / 400 The value of ) is 12.0 W / kg or less and the magnetic flux density (B 50) was found to be 1.65T or higher. Therefore, it can be confirmed that Examples 1 to 4 have excellent magnetic properties by satisfying the value of Equation 1.

[0170] Examples 5 to 8 and Examples 12 to 15 did not satisfy the scope of the present invention with respect to the first rolling condition (i.e., friction coefficient), but satisfied the scope of the present invention with respect to the second rolling condition (i.e., roll speed ratio) and the third rolling condition (i.e., reduction rate per pass). As a result, Examples 5 to 8 and Examples 12 to 15 satisfied the scope of the present invention with a value of Equation 1 greater than 1.9, and iron loss (W 10 / 400 The value of ) is 12.0 W / kg or less and the magnetic flux density (B 50 ) was found to be 1.65T or higher. Therefore, it can be confirmed that Examples 5 to 8 and Examples 12 to 15 have excellent magnetic properties by satisfying the value of Equation 1.

[0171] Examples 9, 11, 16, and 18 did not satisfy the scope of the present invention with respect to the third rolling condition (i.e., reduction rate per pass), but satisfied the scope of the present invention with respect to the first rolling condition (i.e., friction coefficient) and the second rolling condition (i.e., roll speed ratio). As a result, Examples 9, 11, 16, and 18 satisfied the scope of the present invention with a value of Equation 1 greater than 1.9, and iron loss (W 10 / 400 The value of ) is 12.0 W / kg or less and the magnetic flux density (B 50 ) was found to be 1.65T or higher. Therefore, it can be confirmed that Examples 9, 11, 16, and 18 have excellent magnetic properties by satisfying the value of Equation 1.

[0172] Examples 12 to 15 did not satisfy the scope of the present invention with respect to the first rolling condition (i.e., friction coefficient), but satisfied the scope of the present invention with respect to the second rolling condition (i.e., roll speed ratio) and the third rolling condition (i.e., reduction rate per pass). As a result, Examples 12 to 15 satisfied the scope of the present invention with a value of Equation 1 greater than 1.9, and iron loss (W 10 / 400 The value of ) is 12.0 W / kg or less and the magnetic flux density (B 50 ) was found to be 1.65T or higher. Therefore, it can be confirmed that Examples 12 to 15 have excellent magnetic properties by satisfying the value of Equation 1.

[0173] The embodiments of the present invention are merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

Claims

1. In weight % (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P) 0 to 0.015%, and the remainder being iron (Fe) and other unavoidable impurities, A non-oriented electrical steel sheet in which the volume fraction of the texture satisfies the following Equation 1. [Equation 1] (here, f{001} <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.) 2. In Paragraph 1, f{001} of the texture of the above non-oriented electrical steel sheet <130> Non-oriented electrical steel sheet with an orientation fraction of 23% or more.

3. In Paragraph 1, f{113} of the texture of the above non-oriented electrical steel sheet <251> Non-oriented electrical steel sheet with an orientation fraction of 20% or more.

4. In Paragraph 1, f{111} of the texture of the above non-oriented electrical steel sheet <110> Non-oriented electrical steel sheet with an orientation fraction of less than 23%.

5. In Paragraph 1, A non-oriented electrical steel sheet having an average grain size of 90㎛ to 160㎛.

6. In Paragraph 1, The iron loss (W of the above non-oriented electrical steel sheet) 10 / 400 ) is a non-oriented electrical steel sheet with a weight of 12.0 W / kg or less.

7. In Paragraph 1, The magnetic flux density (B) of the above non-oriented electrical steel sheet 50 ) is a non-oriented electrical steel sheet with a thickness of 1.65T or more.

8. A method for manufacturing non-oriented electrical steel sheets, A hot rolling step of manufacturing a hot-rolled plate by hot rolling a slab comprising, in weight% (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P): 0 to 0.015%, and the remainder being iron (Fe) and other unavoidable impurities; A hot rolling annealing step for manufacturing a hot rolling annealed plate by hot rolling and annealing the above hot rolling plate; A cold rolling step for manufacturing a cold rolled plate by cold rolling the hot-rolled annealed plate above; and A cold rolling annealing step for manufacturing a cold rolling annealed plate by annealing the above cold rolling plate; Includes, A method for manufacturing non-oriented electrical steel sheets, wherein the speed ratio of the upper roll and the lower roll in the above cold rolling step is 1.5 or more and less than 3.

0.

9. In Paragraph 8, A method for manufacturing a non-oriented electrical steel sheet, wherein the coefficient of friction between the upper roll and the lower roll in the above cold rolling step is 0.2 or higher.

10. In Paragraph 8, A method for manufacturing a non-oriented electrical steel sheet, wherein the reduction rate per pass in the above cold rolling step is 25% or more and 50% or less.

11. In Paragraph 8, The iron loss (W of the above non-oriented electrical steel sheet) 10 / 400 ) is a method for manufacturing non-oriented electrical steel sheets having a weight of 12.0 W / kg or less 12. In Paragraph 8, The magnetic flux density (B) of the above non-oriented electrical steel sheet 50 ) is a method for manufacturing non-oriented electrical steel sheets with a thickness of 1.65T or more.

13. In Paragraph 8, A method for manufacturing a non-oriented electrical steel sheet, wherein the volume fraction of the texture within the non-oriented electrical steel sheet satisfies the following Equation 1. [Equation 1] (here, f{001} <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.) 14. A motor comprising a motor core, wherein the motor core is, It comprises a non-oriented electrical steel sheet comprising, in weight % (wt%), silicon (Si): 2.0 to 3.8%, aluminum (Al): 0.8 to 1.5%, manganese (Mn): 0.2 to 0.4%, carbon (C): 0 to 0.0080%, sulfur (S): 0 to 0.0050%, nitrogen (N): 0 to 0.0030%, titanium (Ti): 0 to 0.0050%, phosphorus (P) 0 to 0.015%, and the remainder being iron (Fe) and unavoidable impurities. A motor in which the volume fraction of the texture within the above-mentioned non-oriented electrical steel sheet satisfies the following Equation 1. [Equation 1] (here, f{001} <130> {001} in the set organization <130> It is a fraction of, and f{113} <251> {113} in the set organization <251> It is a fraction of, and f{111} <110> {111} in the set organization <110> It is a fraction of.) 15. In Paragraph 14, f{001} of the texture of the above non-oriented electrical steel sheet <130> A motor with a bearing fraction of 23% or more.

16. In Paragraph 14, f{113} of the texture of the above non-oriented electrical steel sheet <251> A motor with a bearing fraction of 20% or more.

17. In Paragraph 14, f{111} of the texture of the above non-oriented electrical steel sheet <110> Motor with a bearing fraction of less than 23%.

18. In Paragraph 14, A motor having an average grain size of 90㎛ to 160㎛ of the above-mentioned non-oriented electrical steel sheet.

19. In Paragraph 14, The iron loss (W of the above non-oriented electrical steel sheet) 10 / 400 ) is a motor with a weight of 12.0W / kg or less.

20. In Paragraph 14, The magnetic flux density (B) of the above non-oriented electrical steel sheet 50 ) is a motor with a value of 1.65T or more.

Images