Non-oriented electrical steel sheet and method for manufacturing non-oriented electrical steel sheet

Abstract

A non-oriented electrical steel sheet according to one embodiment of the present invention comprises 3.0 wt % or more and 3.8 wt % or less of silicon (Si), 0.8 wt % or more and 1.5 wt % or less of aluminum (Al), 0.2 wt % or more and 0.4 wt % or less of manganese (Mn), more than 0 wt % and 0.0030 wt % or less of lanthanum (La), more than 0 wt % and 0.0030 wt % or less of dysprosium (Dy), and the balance of iron (Fe) and other inevitable impurities, and has a magnetic anisotropy parameter (A(h)) of 0.23 or less, whereby an electrical steel sheet having excellent magnetic properties and a method for manufacturing a non-oriented electrical steel sheet may be implemented.

Description

Non-oriented electrical steel sheet 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 a non-oriented electrical steel sheet.

[0002] In line with recent global policies to reduce carbon dioxide emissions to combat global warming, conventional internal combustion engine vehicles are rapidly being replaced by eco-friendly vehicles such as hybrid, electric, and hydrogen-powered vehicles. Eco-friendly vehicles utilize electric motors to generate the necessary driving force and significantly reduce harmful exhaust gas emissions, thereby minimizing environmental pollution.

[0003] As interest in and demand for eco-friendly vehicles grows, so does the demand for electric motors, which power these vehicles. Electric motors use electricity to generate the power needed for vehicles. Energy efficiency, which allows them to operate for longer periods of time using the same amount of energy, is a crucial technological element.

[0004] In particular, high energy efficiency is required for electric motors used to power electric vehicles. This energy efficiency is influenced by the magnetic properties of non-oriented electrical steel, a soft magnetic material used as the core material for electric motors.

[0005] A representative magnetic characteristic of non-oriented electrical steel is core loss. Core loss refers to the energy loss that occurs during the magnetization process of the material. It can be expressed as energy loss at specific magnetic flux densities and frequencies. To reduce this core loss, the material must possess high remanence and low coercivity.

[0006] Rare earth elements are typically added to achieve high remanence. However, while adding rare earth elements increases remanence, it also increases coercivity. This can reduce the iron loss reduction effect. Furthermore, rare earth elements can increase production costs, leading to cost issues.

[0007] Therefore, it is necessary to develop a non-oriented electrical steel sheet and a method for manufacturing a non-oriented electrical steel sheet having excellent magnetic properties, in which the remanent magnetism is increased and the increase in coercivity is suppressed by optimizing the rare earth element content.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] (Patent Document 1) Korean Patent Publication No. 2023-0144606

[0011] The present invention has been devised to solve the above problems, and the object of the present invention is to provide a non-oriented electrical steel sheet having excellent magnetic properties and a method for manufacturing a non-oriented electrical steel sheet.

[0012] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0013] A non-oriented electrical steel sheet according to one embodiment of the present invention contains 3.0 wt% or more and 3.8 wt% or less of silicon (Si), 0.8 wt% or more and 1.5 wt% or less of aluminum (Al), 0.2 wt% or more and 0.4 wt% or less of manganese (Mn), 0 wt% or more and 0.0030 wt% or less of lanthanum (La), 0 wt% or more and 0.0030 wt% or less of dysprosium (Dy), and the remainder iron (Fe) and other unavoidable impurities.

[0014] Additionally, the magnetic anisotropy parameter (A(h)) is less than 0.23.

[0015] [Formula 1]

[0016]

[0017] In the above equation 1, α1, α2 and α3 are the cosine values ​​cosA, cosB and cosC, respectively, when the angles formed by the crystal axis of the crystal grain and the specimen axis are A, B and C, respectively.

[0018] A(h) is the average of the a(h) values ​​of each crystal grain.

[0019] In addition, the following equation 2 can be satisfied.

[0020] [Formula 2]

[0021] Br / 10*Hci*A(h)≥10

[0022] (In Equation 2, Br represents the remanent magnetism, Hci represents the coercive force, and A(h) represents the magnetic anisotropy parameter.)

[0023] Also, the magnetic flux density (B 50 ) is 1.63 T or more, iron loss (W 10 / 400 ) may be less than 14.1 W / kg.

[0024] In addition, it may further include at least one of carbon (C) exceeding 0 wt% and 0.002 wt% or less, sulfur (S) exceeding 0 wt% and 0.002 wt% or less, nitrogen (N) exceeding 0 wt% and 0.002 wt% or less, titanium (Ti) exceeding 0 wt% and 0.002 wt% or less, and phosphorus (P) exceeding 0 wt% and 0.014 wt% or less.

[0025] A method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention comprises a steel preparation step including the above-described alloy composition, a hot rolling step of hot-rolling the steel sheet to form a hot-rolled steel sheet, a hot-rolling annealing step of annealing the hot-rolled steel sheet, a cold rolling step of cold-rolling the hot-rolled steel sheet that has undergone the hot-rolling annealing step to form a cold-rolled steel sheet, and a cold-rolling annealing step of annealing the cold-rolled steel sheet.

[0026] Additionally, the hot-rolled annealing step can anneal the hot-rolled steel sheet at 950 to 1100°C for 30 to 150 seconds.

[0027] Additionally, the cold rolling annealing step can anneal the cold rolled steel sheet at 800 to 1150°C for 5 to 150 seconds.

[0028] In addition, the steel may further include at least one of carbon (C) exceeding 0 wt% and 0.002 wt% or less, sulfur (S) exceeding 0 wt% and 0.002 wt% or less, nitrogen (N) exceeding 0 wt% and 0.002 wt% or less, titanium (Ti) exceeding 0 wt% and 0.002 wt% or less, and phosphorus (P) exceeding 0 wt% and 0.014 wt% or less.

[0029] According to one embodiment of the present invention, by controlling the content of rare earth elements, a non-oriented electrical steel sheet having excellent magnetic properties and a method for manufacturing a non-oriented electrical steel sheet can be implemented by increasing remanent magnetism and suppressing an increase in coercive force.

[0030] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0031] 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.

[0032] Contains less than 0 wt% of lanthanum (La) and less than 0 wt% of lanthanum (La), more than 0 wt% of lanthanum (La) and less than 0.0030 wt% of lanthanum (La), more than 0 wt% of lanthanum (La) and less than 0.0030 wt% of lanthanum (La), and the remainder iron (Fe) and other unavoidable impurities.

[0033] In addition, the steel may further include at least one of carbon (C) exceeding 0 wt% and 0.002 wt% or less, sulfur (S) exceeding 0 wt% and 0.002 wt% or less, nitrogen (N) exceeding 0 wt% and 0.002 wt% or less, titanium (Ti) exceeding 0 wt% and 0.002 wt% or less, and phosphorus (P) exceeding 0 wt% and 0.014 wt% or less.

[0034] The alloy composition has been previously described, so a detailed explanation will be omitted. Furthermore, since the alloy composition does not substantially change during the manufacturing process described below, the alloy composition of the steel material and the alloy composition of the final product, the non-oriented electrical steel sheet, are substantially identical.

[0035] Hereinafter, each step of a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention will be described in detail.

[0036] The steel preparation step, which involves preparing steel, is a step for preparing semi-finished products for manufacturing the final product, non-oriented electrical steel sheet. More specifically, this step may involve designing alloy components within the alloy composition range according to one embodiment of the present invention to manufacture semi-finished products. The semi-finished products may be slabs, but are not necessarily limited thereto. Furthermore, the slabs may be manufactured using any known steelmaking process in the relevant technical field, such as a casting process.

[0037] According to one embodiment of the present invention, a method for manufacturing a non-oriented electrical steel sheet may include, after a steel preparation step, performing a hot rolling step of hot-rolling the steel to form a hot-rolled steel sheet. The hot rolling step may include a reheating step, a hot rolling step, and a coiling step.

[0038] First, the reheating process, performed prior to the hot rolling process, may reheat the steel for subsequent processing. Specifically, it may be a step where the steel is placed in a heating furnace and uniformly heated, facilitating plastic deformation.

[0039] At this time, if the reheating temperature is below 1000℃, the rolling load increases, which can make hot rolling difficult. On the other hand, if the reheating temperature exceeds 1250℃, precipitates formed by carbon (C), sulfur (S), nitrogen (N), etc. in the steel are re-dissolved, which can lead to the formation of fine precipitates during the subsequent rolling and annealing processes. These fine precipitates can inhibit grain growth and increase iron loss.

[0040] Therefore, the reheating process according to one embodiment of the present invention can be performed at a temperature of 1000 to 1250°C.

[0041] Next, a hot rolling process can be performed, in which the reheated steel is hot-rolled to form a hot-rolled steel sheet. The hot rolling process can include rough rolling and finish rolling. Here, rough rolling can refer to forming the steel into a rolled sheet with an appropriate shape, thickness, and width, while finish rolling can refer to adjusting the steel to a specified thickness and width and rolling it at a finishing temperature appropriate for the intended use to achieve a good surface finish and shape.

[0042] At this time, the finishing temperature of the hot rolling process can be carried out at a temperature that allows for uniform tissue formation and appropriate strength enhancement, and the finishing temperature can be 860 to 900℃. If the finishing temperature is below 860℃, dynamic recrystallization may not occur sufficiently, making it difficult to homogenize the microstructure, which may lower the uniformity of the final texture and result in inferior magnetic properties. If the finishing temperature exceeds 900℃, the problem of a rapid decrease in the strength of the steel may occur.

[0043] Afterwards, a coiling process can be performed to coil the hot-rolled steel sheet formed through the hot rolling process. The coiling temperature can range from 550 to 650°C. If the coiling temperature is below 550°C, brittleness increases, potentially leading to sheet fracture. Furthermore, the grain size decreases, preventing sufficient grain growth even after annealing. Conversely, if the coiling temperature exceeds 650°C, fine precipitates can form, increasing iron loss.

[0044] The thickness of the hot-rolled steel sheet formed through the hot rolling process should preferably be 1.8 to 3.5 mm. If the hot-rolled steel sheet is excessively thin, less than 1.8 mm, the resulting cold-rolled thickness may be insufficient, resulting in shape defects during product application. Conversely, if the hot-rolled steel sheet exceeds 3.5 mm, the cold-rolling reduction ratio increases, increasing the fraction of grain structures unfavorable to magnetic properties, potentially degrading magnetic properties.

[0045] According to one embodiment of the present invention, a non-oriented electrical steel sheet may be subjected to a hot-rolling annealing step, which involves hot-rolling the hot-rolled steel sheet after the hot-rolling step. The hot-rolling annealing step may be a hot-rolling annealing step performed to ensure uniformity of the microstructure of the hot-rolled steel.

[0046] The reasons for performing hot-rolled annealing are as follows. When the silicon content is 3.0 wt% or more, the α-ferrite single phase is maintained without phase transformation into a solid state during heating from room temperature to the melting point. However, dynamic recrystallization (DRX) does not occur during this process, resulting in the formation of elongated unrecrystallized parts. These unrecrystallized parts have high internal residual stresses and are unstable, which can lead to increased anisotropy and plate failure.

[0047] Therefore, the hot rolling annealing step may be a step of performing heat treatment at an appropriate temperature to promote recrystallization of unrecrystallized grains and thereby obtain a uniform equiaxed grain.

[0048] The hot-rolling annealing temperature according to the present invention may be 950 to 1100°C. If the hot-rolling annealing temperature is lower than 950°C, the elongated cast structure may remain after hot rolling, causing microstructural inhomogeneity. On the other hand, if the hot-rolling annealing temperature exceeds 1100°C, the grains may grow excessively, leading to severe grain size deviations, and oxidation may occur, which may deteriorate the magnetic properties of the final product.

[0049] Additionally, hot-rolled annealing may include a heat treatment step for 30 to 150 seconds to form an appropriate grain size under the above-described temperature conditions. At this time, the heating rate to the heat treatment temperature may be 20°C / s or more, and the cooling rate after the heat treatment may be 30°C / s or more.

[0050] A method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention may further include a pickling treatment step after the hot-rolled annealing step. The pickling treatment may be performed by reacting fine residual scales that cannot be removed mechanically with an acid solution.

[0051] Thereafter, the method for manufacturing a non-oriented electrical steel sheet according to the present invention may perform a cold rolling step of cold rolling the hot-rolled steel sheet that has undergone a hot-rolling annealing step to form a cold-rolled steel sheet. The cold rolling step may be a cold rolling process that further thins the thickness of the steel sheet by rolling the hot-rolled annealed hot-rolled steel sheet at a temperature below the recrystallization temperature.

[0052] More specifically, it may be a process for rolling a hot-rolled steel sheet to a thickness and width that meet the specifications of the final product. The cold rolling step according to the present invention may include a step of cold rolling a hot-rolled steel sheet to produce a cold-rolled steel sheet having a thickness of 0.2 to 0.3 mm. At this time, the reduction ratio may be 60% or more.

[0053] A method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention may include performing a cold rolling annealing step, after a cold rolling step, of cold rolling the cold rolled steel sheet. The cold rolling annealing may be performed at an appropriate temperature to improve magnetic and mechanical properties.

[0054] At this time, the appropriate temperature for cold rolling annealing may be 800 to 1150°C. If the cold rolling annealing temperature is lower than 800°C, the cold rolling annealing temperature may be insufficient to relieve residual stress, resulting in poor iron loss. Furthermore, the grain size after annealing may be small, resulting in poor magnetic flux density and iron loss.

[0055] On the other hand, if the cold rolling annealing temperature exceeds 1150℃, excessive grain growth may increase eddy current loss, which may increase iron loss. In addition, precipitates may re-dissolve, forming fine precipitates, which may deteriorate magnetic properties.

[0056] Additionally, the cold rolling annealing according to the present invention can be maintained for 5 to 150 seconds within the aforementioned temperature range. The heating rate to the aforementioned temperature can be 10°C / s or more, and the cooling rate after heat treatment can be 20°C / s or more.

[0057] The cold-rolled annealing step can be performed in a mixed atmosphere containing hydrogen (H2) and nitrogen (N2) to prevent oxidation or nitriding of the surface of the cold-rolled steel sheet. This can improve the surface quality of the cold-rolled steel sheet.

[0058] A method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention may further include a coating step after the cold-rolled annealing step. The coating step may be performed to secure the insulation properties of the non-oriented electrical steel sheet and improve the punchability, and may mean forming an insulating film on the surface of the cold-rolled steel sheet after the cold-rolled annealing step. The coating step may be performed using any process known in the art.

[0059] This allows for excellent magnetic properties. More specifically, the magnetic flux density (B 50 ) can be greater than 1.63 T, and the iron loss (W 10 / 400 ) may be less than 14.1 W / kg.

[0060]

[0061] Examples and Comparative Examples

[0062] Below, the composition and operation of the present invention will be explained through experimental examples. However, these examples are provided to aid understanding of the present invention and are not intended to limit the present invention.

[0063]

[0064] (Method for manufacturing non-oriented electrical steel sheet specimens)

[0065] The specimen of the non-oriented electrical steel sheet of the present invention includes the alloy components described in Tables 1 and 2 below, and the remainder other than the alloy components described in Tables 1 and 2 below includes iron (Fe).

[0066] Classification Alloy Element (Wt%) Alloy Element (ppm) Alloy Element (ppm) SiAlMnLaDyCSNTiP Example 13.030.820.222916111218876 Example 23.450.970.2919251011141498 Example 33.731.270.211571291216108 Example 43.41.250.24658121010115 Example 53.741.060.34192210171515108 Example 63.411.070.34282999141970 Example 7 3.051.420.261422167191888Example 83.241.070.231171613171180Example 93.440.840.218289719788Example 103.290.890.2213171620141787Example 113.520.870.2819221614131194Example 123.361.40.2323191018112097Example 133.631.230.282821129151688

[0067] Classification Alloy Element (Wt%) Alloy Element (ppm) Alloy Element (ppm) SiAlMnLaDyCSNTiP Comparative Example 13.921.410.25121811151113130 ​​Comparative Example 23.31.740.2677185149104 Comparative Example 33.471.650.37272379288129 Comparative Example 43.020.850.3417699321377 Comparative Example 53.661.140.212779893779 Comparative Example 63.621.30.41021913263384 Comparative Example 73.481.470.24291473681312 0Comparison Example 83.421.050.21091510131187Comparison Example 93.551.480.32807121214140Comparison Example 103.41.470.23001710196122Comparison Example 113.530.920.2252171916191182Comparison Example 123.671.080.371444111511578Comparison Example 133.21.10.2241491496683Comparison Example 143.020.870.2504513168676Comparison Example 153.731.130.27 3801719151783Comparative Example 163.581.020.314315102299130Comparative Example 173.541.280.231339614281772Comparative Example 183.731.30.36241021251418110Comparative Example 193.351.420.469331115613111Comparative Example 202.871.250.342410131191088Comparative Example 213.180.750.32172917101812101Comparative Example 222.930.750.272621 105136112Comparative Example 232.90.80.310201318139101Comparative Example 243.11.140.3688710161271Comparative Example 253.771.030.262891919171493Comparative Example 263.011.360.2327231312161968Comparative Example 273.31.030.38111714161510122Comparative Example 283.240.940.23161316121311722Comparative Example 293.381.070.23818915992413

[0068] A specimen of the non-oriented electrical steel sheet of the present invention can be manufactured as follows. A slab having the alloy compositions described in Tables 1 and 2 is manufactured, the slab is reheated to 1150°C, and then hot-rolled at a finishing temperature of 870°C to manufacture a hot-rolled steel sheet. The hot-rolled steel sheet is hot-rolled and annealed for 70 seconds at the temperatures described in Tables 2 and 3 below, and the hot-rolled steel sheet subjected to the hot-rolling annealing is pickled.

[0069] Thereafter, cold rolling was performed to manufacture cold-rolled steel sheets having the thicknesses listed in Tables 1 and 2. Next, the cold-rolled steel sheets were annealed for 90 seconds at the temperatures listed in Tables 3 and 4 below, in a mixed atmosphere of nitrogen (N2) and hydrogen (H2). Thereafter, a final non-oriented electrical steel sheet specimen was manufactured through a coating process.

[0070] Other process conditions not described in the above-described manufacturing method were controlled as control variables and were identically controlled within the range described in the method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention.

[0071]

[0072] (Method for measuring the properties of non-oriented electrical steel sheets)

[0073] 1. Magnetic anisotropy parameter (A(h))

[0074] To measure the magnetic anisotropy parameters, EBSD (Electron backscatter diffraction) measurement specimens were prepared so that the ND plane (Normal direction plane) of the steel plate could be observed. The step size was 10 ㎛, and the length × width of the specimen was 20 mm × 20 mm.

[0075] Afterwards, the a(h) value of the crystal grains in the test piece was obtained through the following equation 1, and the average of the a(h) values ​​of each crystal grain was calculated and the average value was used as the magnetic anisotropy parameter (A(h)).

[0076] [Formula 1]

[0077]

[0078] (In the above equation 1, α1, α2, and α3 represent the values ​​of cosA, cosB, and cosC, respectively, when the angles formed by the crystal axis of the crystal grain and the specimen axis are A, B, and C, respectively.)

[0079]

[0080] 2. Remanent magnetism (Br) and coercive force (Hci)

[0081] A vibrating sample magnetometer (VSM) was used to measure the residual magnetism and coercive force. The applied magnetic field was recorded through the VSM, and the electromotive force obtained when the sample was vibrated was recorded.

[0082] At this time, the LakeShore 7400 equipment was used to measure the residual magnetism and coercive force. The detailed analysis conditions are as follows.

[0083] Saturating field: ± 10 kOe

[0084] Field Increment: 100 Oe

[0085] Number of Points: 401

[0086] Ramp Rate: 50 Oe / s

[0087]

[0088] 3. Iron loss (W 10 / 400 ) and magnetic flux density (B 50 )

[0089] The core loss and magnetic flux density of the non-oriented electrical steel sheet specimen of the present invention were measured based on the test method specified in the IEC 60404-2 international standard, and were measured using the single sheet test method. At this time, the size of the specimen was 60 mm × 60 mm.

[0090]

[0091] (Evaluation results of non-oriented electrical steel sheets)

[0092] The hot rolling annealing (APL) and cold rolling annealing (ACL) temperatures of the examples and comparative examples are shown in Tables 3 and 4 below.

[0093] In addition, the magnetic anisotropy parameter (A(h)), remanence (Br) and coercive force (Hci), and magnetic flux density (B) of the examples and comparative examples 50 ) and iron loss (W 10 / 400 ) values ​​are shown in Tables 3 and 4 below.

[0094] Classification APL temperature (℃) ACL temperature (℃) A (h) Br (G) Hci (G) [Formula 2] Left side value B 50 (T)W 10 / 400 (W / kg)Example 1 1000 9500.18 147 7.34 11.11.67 12.7Example 2 1000 9500.21 827.46 12.21.68 12.4Example 3 1000 9500.23 2007.6 111.41.7 11.3Example 4 1000 9500.19 148 7.53 10.31.64 13.1Example 5 1000 9500.21 1737.44 11.11.66 12.1Example 6 1000 9500.18 1937.41 14.51.66 12.6Example 7 1000 95 00.171377.4510.81.6313.9Embodiment 810008500.22501012.51.6313.7Embodiment 99509500.182639.615.21.6512.8Embodiment 1010009500.162348.816.61.6513Embodiment 1110009500.211184.911.51.6811.8Embodiment 12100011400.221375.2121.6412.3Embodiment 1310809500.211516.311.41.711.2

[0095] Classification APL temperature (℃) ACL temperature (℃) A (h) Br (G) Hci (G) [Formula 2] Left side value B 50 (T)W 10 / 400(W / kg) Comparative Example 110009500.191675.4916.01 (During rolling) Fracture) Comparative Example 2 10009500.231587.59.161.6114.5 Comparative Example 3 10009500.231427.678.051.5915.1 Comparative Example 4 10009500.251296.747.631.6114.8 Comparative Example 5 10009500.231476.669.61.614.9 Comparative Example 6 10009500.241657.519.151.6114.8 Comparative Example 7 10009500.231436.529.541.6214.2 Comparative Example 8 10009500.2615 27.627.721.6114.7Comparative Example 910009500.251507.517.991.6115Comparative Example 1010009500.261257.636.321.5915.6Comparative Example 1110009500.271427.527.121.5815.9Comparative Example 1210009500.251537.428.291.5915.5Comparative Example 1310009500.281127.55.311.5816.2Comparative Example 1410009500.241247.546.811.5915. 5Comparative Example 15 1000 9500.21 1828.839.821.614.5Comparative Example 16 1000 9500.25 1607.678.34 1.615Comparative Example 17 1000 9500.23 1577.618.98 1.6114.9Comparative Example 18 1000 9500.21 719.638.88 1.615.3Comparative Example 19 1000 9500.25 1137.585.921.6214.4Comparative Example 20 1000 9500.26 984.777.93 1.5815.4Comparative Example 21 1000 9500.241 135.638.361.615.1Comparative Example 2210009500.261037.835.061.5915.6Comparative Example 2310009500.271107.585.371.5815.4Comparative Example 249009500.261265.29.31.6315.4Comparative Example 2510807500.231728.668.61.714.6Comparative Example 269009500.261327.636.71.6215.6Comparative Example 2710007500.251517.687.91.6214.3Comparative Example 28110011800.271307.606.31.6114.8 Comparative example 2911509500.231637.849.01.6514.5

[0096] Referring to Table 1 and Table 3, in the case of an embodiment satisfying the alloy composition and manufacturing method according to an embodiment of the present invention, it can be confirmed that the magnetic anisotropy parameter (A(h)) is 0.23 or less. In addition, it can be confirmed that the value on the left side of Equation 2 is 10 or more. At this time, the magnetic flux density (B) of the embodiment 50 ) is 1.63 T or more, and the iron loss (W 10 / 400 ) It can be confirmed that the value is less than 14.1 W / kg.

[0097] On the other hand, referring to Table 2 and Table 4, it can be confirmed that the magnetic properties of the comparative examples that do not satisfy the alloy composition and manufacturing method according to one embodiment of the present invention are inferior to those of the examples.

[0098] More specifically, in the case of a comparative example that does not satisfy the alloy composition according to one embodiment of the present invention, it can be confirmed that the left side value of Equation 2 is less than 10. At this time, the comparative example has a lower magnetic flux density (B) than the embodiment. 50 ) value, and has a higher iron loss (W) than the example 10 / 400 ) can be confirmed to have a value.

[0099] In addition, in the case of a comparative example that does not satisfy the hot rolling annealing temperature or cold rolling annealing temperature range according to one embodiment of the present invention, it can be confirmed that the value on the left side of Equation 2 is less than 10. At this time, the iron loss (W) of the comparative example 10 / 400 ) can be confirmed to exceed 14.1 W / kg.

[0100] As described above, preferred embodiments of the present invention have been described. It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms, in addition to the embodiments described above, without departing from the spirit or scope thereof. Therefore, the above-described embodiments should be considered illustrative rather than restrictive, and accordingly, the present invention is not limited to the above description, but may be modified within the scope of the appended claims and their equivalents.

Claims

1. Contains 3.0 wt% or more of silicon (Si) and 3.8 wt% or less, 0.8 wt% or more of aluminum (Al) and 1.5 wt% or less, 0.2 wt% or more of manganese (Mn) and 0.4 wt% or less, 0 wt% or more of lanthanum (La) and 0.0030 wt% or less, 0 wt% or more of dysprosium (Dy) and 0.0030 wt% or less, the remainder being iron (Fe) and other unavoidable impurities. Non-oriented electrical steel sheet with magnetic anisotropy parameter (A(h)) of 0.23 or less: [Formula 1] In the above equation 1, α1, α2 and α3 are the cosine values ​​cosA, cosB and cosC, respectively, when the angles formed by the crystal axis of the crystal grain and the specimen axis are A, B and C, respectively. A(h) is the average of the a(h) values ​​of each crystal grain.

2. In paragraph 1, Non-oriented electrical steel sheet satisfying the following equation 2: [Formula 2] Br / 10*Hci*A(h)≥10 (In Equation 2, Br represents the remanent magnetism, Hci represents the coercive force, and A(h) represents the magnetic anisotropy parameter.) 3. In paragraph 1, Magnetic flux density (B 50 ) is 1.63 T or more, iron loss (W 10 / 400 ) Non-oriented electrical steel sheet having a strength of 14.1 W / kg or less.

4. In paragraph 1, A non-oriented electrical steel sheet further comprising at least one of carbon (C) exceeding 0 wt% and not more than 0.002 wt%, sulfur (S) exceeding 0 wt% and not more than 0.002 wt%, nitrogen (N) exceeding 0 wt% and not more than 0.002 wt%, titanium (Ti) exceeding 0 wt% and not more than 0.002 wt%, and phosphorus (P) exceeding 0 wt% and not more than 0.014 wt%.

5. Steel preparation stage; A hot rolling step of hot rolling the above steel to form a hot rolled steel plate; A hot rolling annealing step for annealing the above hot rolled steel sheet; A cold rolling step of forming a cold rolled steel sheet by cold rolling the hot rolled steel sheet that has undergone the above hot rolling annealing step; and Including a cold rolling annealing step for annealing the above cold rolled steel sheet, The above steel is, A method for manufacturing a non-oriented electrical steel sheet comprising silicon (Si) at 3.0 wt% or more and 3.8 wt% or less, aluminum (Al) at 0.8 wt% or more and 1.5 wt% or less, manganese (Mn) at 0.2 wt% or more and 0.4 wt% or less, lanthanum (La) at 0 wt% or more and 0.0030 wt% or less, dysprosium (Dy) at 0 wt% or more and 0.0030 wt% or less, the remainder being iron (Fe) and other unavoidable impurities.

6. In paragraph 5, The hot rolling annealing stage is A method for manufacturing non-oriented electrical steel sheets by annealing hot-rolled steel sheets at 950 to 1100°C for 30 to 150 seconds.

7. In paragraph 5, The cold rolling annealing stage is A method for manufacturing non-oriented electrical steel sheets by annealing cold-rolled steel sheets at 800 to 1150°C for 5 to 150 seconds.

8. In paragraph 5, A method for manufacturing a non-oriented electrical steel sheet, further comprising at least one of carbon (C) exceeding 0 wt% and not more than 0.002 wt%, sulfur (S) exceeding 0 wt% and not more than 0.002 wt%, nitrogen (N) exceeding 0 wt% and not more than 0.002 wt%, titanium (Ti) exceeding 0 wt% and not more than 0.002 wt%, and phosphorus (P) exceeding 0 wt% and not more than 0.014 wt%.

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