Non-oriented electrical steel sheet and its manufacturing method

Abstract

A non-oriented electrical steel sheet having excellent core loss and magnetic flux density characteristics and a method for manufacturing the same are provided. [Solution] The alloy contains, by weight, one or more of Si: 3.0 to 5.0%, Mn: 0.1 to 1.4%, Al: 0.3 to 1.3%, P: 0.001 to 0.01%, S: 0.003% or less (excluding 0%), C: 0.005% or less (excluding 0%), N: 0.005% or less (excluding 0%), Ti: 0.005% or less (excluding 0%), Sn: 0.001 to 0.08%, and Sb: 0.001 to 0.08%, with the remainder being Fe and other unavoidable impurities, and the average size of the MnS-based precipitates is 0.5 μm or more, The ratio of precipitates having an average size of 3 μm or more is 5% by area or less of the total precipitates.

Description

[Technical Field]

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

[0002] Electrical steel sheets are used as materials for transformers, motors, and electrical equipment, and unlike general carbon steel, which emphasizes workability such as mechanical properties, they are functional products in which electrical properties are important. Required electrical properties include low iron loss, high magnetic flux density, high magnetic permeability, and high dot ratio. Electrical steel sheets are further divided into grain-oriented and non-oriented types. Grain-oriented electrical steel sheets are made with a Goss texture ({110} <001> Non-oriented electrical steel sheet has excellent magnetic properties in all directions on the rolled sheet, due to the formation of a texture throughout the steel sheet.

[0003] In the production process of non-oriented electrical steel sheets, a slab is generally subjected to hot rolling, cold rolling and final annealing, followed by forming an insulating coating layer. The manufacturing process of grain-oriented electrical steel sheets involves hot rolling a slab, pre-annealing, cold rolling, decarburization annealing, and final annealing, followed by forming an insulating coating layer.

[0004] Among these, non-oriented electrical steel sheets have uniform magnetic properties in all directions and are commonly used as materials for motor cores, generator cores, electric motors, small transformers, etc. The main magnetic properties of non-oriented electrical steel sheets are iron loss and magnetic flux density. Lower iron loss reduces the iron loss that occurs during the magnetization process of the iron core, improving efficiency. Higher magnetic flux density allows for larger magnetic steel to be induced with the same energy, and requires less current to achieve the same magnetic flux density, reducing copper loss and improving energy efficiency.

[0005] However, there are limits to improving the properties of non-oriented electrical steel sheets based on conventional metallurgical techniques. In the case of non-oriented electrical steel sheets that are not subjected to stress relief annealing after processing, the degree of iron loss degradation does not meet the strict iron loss requirements of energy efficiency regulations and the requirements of industries related to the production, transmission, conversion and utilization of electrical energy.

[0006] Recently, in response to the demands of such industries, there has been a need to develop non-oriented electrical steel sheets with low iron loss and high magnetic flux density in the manufacture of motors with higher efficiency. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a non-oriented electrical steel sheet having excellent core loss and magnetic flux density properties, and a method for manufacturing the same. [Means for solving the problem]

[0008] The non-oriented electrical steel sheet of the present invention is characterized in that it contains, by weight %, one or more of Si: 3.0 to 5.0%, Mn: 0.1 to 1.4%, Al: 0.3 to 1.3%, P: 0.001 to 0.01%, S: 0.003% or less (excluding 0%), C: 0.005% or less (excluding 0%), N: 0.005% or less (excluding 0%), Ti: 0.005% or less (excluding 0%), Sn: 0.001 to 0.08%, and Sb: 0.001 to 0.08%, with the balance being Fe and other unavoidable impurities, and in that the average size of the MnS-based precipitates is 0.5 μm or more, and the fraction of precipitates having an average size of 3 μm or more is 5 area % or less of the total precipitates.

[0009] The method for producing a non-oriented electrical steel sheet of the present invention includes the steps of heating a slab containing, by weight, one or more of Si: 3.0 to 5.0%, Mn: 0.1 to 1.4%, Al: 0.3 to 1.3%, P: 0.001 to 0.01%, S: 0.003% or less (excluding 0%), C: 0.005% or less (excluding 0%), N: 0.005% or less (excluding 0%), Ti: 0.005% or less (excluding 0%), Sn: 0.001 to 0.08%, and Sb: 0.001 to 0.08%, with the remainder being Fe and other unavoidable impurities. The method includes the steps of: finish hot rolling the heated slab to obtain a hot-rolled sheet; first cold rolling the hot-rolled sheet at a cold reduction of 40 to 79% to obtain a first cold-rolled sheet; first annealing the first cold-rolled sheet; final cold rolling the primarily annealed first cold-rolled sheet to obtain a second cold-rolled sheet; and final annealing the second cold-rolled sheet, wherein the finish cold-rolling temperature during the first cold rolling is 50 to 160°C, and the final annealing is performed at 900 to 1100°C for 50 to 120 seconds. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a non-oriented electrical steel sheet having excellent core loss and magnetic flux density properties, and a method for manufacturing the same. DETAILED DESCRIPTION OF THE INVENTION

[0011] A non-oriented electrical steel sheet according to an embodiment of the present invention will be described below. First, the alloy composition will be described. The contents of the alloy compositions described below are in weight percent unless otherwise specified.

[0012] Si: 3.0 to 5.0% Silicon (Si) plays a role in increasing the resistivity of the material and reducing iron loss. If the Si content is less than 3.0%, the effect of improving iron loss may be insufficient. If the Si content exceeds 5.0%, the brittleness of the material increases, which may cause sheet breakage during coiling and cold rolling, resulting in a rapid decrease in rolling productivity. Therefore, the Si content is preferably in the range of 3.0 to 5.0%. It is more preferable that the upper limit of the Si content is 4.5%.

[0013] Mn: 0.1 to 1.4% Manganese (Mn) increases the resistivity of the material, improves iron loss, and plays a role in forming sulfides. If the Mn content is less than 0.1%, fine sulfides may precipitate, reducing magnetic properties. If the Mn content exceeds 1.4%, it may promote the formation of a {111} texture, which is unfavorable to magnetic properties, resulting in a decrease in magnetic flux density. Therefore, the Mn content is preferably in the range of 0.1 to 1.4%.

[0014] Al: 0.3 to 1.3% Aluminum (Al) increases the resistivity of the material, reduces iron loss, improves rollability, and improves workability during cold rolling. If the Al content is less than 0.3%, it is ineffective in reducing high-frequency iron loss, and the precipitation temperature of AlN is lowered, resulting in the formation of fine nitrides, which can reduce magnetic properties. If the Al content exceeds 1.3%, excessive nitrides are formed, which can deteriorate magnetic properties and cause problems in all processes, such as steelmaking and continuous casting, significantly reducing productivity. Therefore, the Al content is preferably in the range of 0.3 to 1.3%.

[0015] P: 0.001 to 0.01% Phosphorus (P) segregates at grain boundaries to improve texture, increase resistivity, and reduce iron loss. If the P content is less than 0.001%, the amount of segregation may be too small to improve texture. If the P content exceeds 0.01%, it may lead to the formation of a texture unfavorable to magnetic properties, fail to improve texture, and segregate excessively at grain boundaries, reducing rollability and workability, making production difficult. Therefore, the P content is preferably in the range of 0.001 to 0.01%.

[0016] S: 0.003% or less (excluding 0%) Sulfur (S) is an element that forms fine sulfides inside the base material, thereby suppressing grain growth and weakening iron loss. If the S content exceeds 0.003%, it may inhibit grain growth in combination with Mn or the like, or the magnetic properties after processing may be excessively reduced. Therefore, it is preferable that the S content be 0.003% or less (excluding 0%).

[0017] C: 0.005% or less (excluding 0%) Carbon (C) is an element that suppresses ferrite grain growth during annealing, excessively degrades magnetic properties during processing, and bonds with Ti and other elements to reduce magnetic properties. If the C content exceeds 0.005%, magnetic properties may be excessively reduced. Therefore, the C content is preferably 0.005% or less (excluding 0%). The C content is more preferably 0.004% or less, and even more preferably 0.003% or less.

[0018] N: 0.005% or less (excluding 0%) Nitrogen (N) is an element that not only combines with Al, Ti, etc. to form fine, elongated precipitates inside the base material, but also combines with other impurities to form fine nitrides, which inhibit grain growth and worsen iron loss. If the N content exceeds 0.005%, there is a risk of excessive deterioration in magnetic properties. Therefore, the N content is preferably 0.005% or less (excluding 0%). The N content is more preferably 0.004% or less, and even more preferably 0.003% or less.

[0019] Ti: 0.005% or less (excluding 0%) Titanium (Ti) is an element that has a strong tendency to form precipitates in steel and inhibits grain growth by forming fine carbides or nitrides within the base material. If the Ti content exceeds 0.005%, a large amount of carbides and nitrides is formed, which deteriorates the magnetic properties, such as increasing iron loss. Therefore, the Ti content is preferably 0.005% or less (excluding 0%). The Ti content is more preferably 0.004% or less, and even more preferably 0.003% or less.

[0020] The non-oriented steel sheet of the present invention may contain one or more of Sn: 0.001 to 0.08% and Sb: 0.001 to 0.08%. Sn: 0.001 to 0.08% Tin (Sn) is an element that segregates at grain boundaries and surfaces to improve the texture of steel sheets and inhibit surface oxidation, thereby enhancing magnetic properties. If the Sn content is less than 0.001%, it is difficult to fully achieve these effects. If the Sn content exceeds 0.08%, the grain boundary segregation becomes severe, deteriorating surface quality, and the hardness increases, which can cause breakage of the cold-rolled sheet and reduce rollability. Therefore, the Sn content is preferably in the range of 0.001 to 0.08%.

[0021] Sb: 0.001 to 0.08% Antimony (Sb) is an element that segregates at grain boundaries and surfaces to improve the texture of steel sheets and inhibit surface oxidation, thereby enhancing magnetic properties. If the Sb content is less than 0.001%, it is difficult to fully achieve the above effects. If the Sb content exceeds 0.08%, the segregation at grain boundaries becomes severe, deteriorating surface quality, and increasing hardness can cause breakage of the cold-rolled sheet, resulting in reduced rollability. Therefore, the Sb content is preferably in the range of 0.001 to 0.08%.

[0022] The total content of Sn and Sb is preferably 0.1% or less. If the total content of Sn and Sb exceeds 0.1%, the degree of grain segregation increases, which may result in reduced crystal growth and deteriorated magnetic properties.

[0023] The remaining component is iron (Fe). However, in a normal manufacturing process, unintentional impurities may be inevitably mixed in from the raw materials or the surrounding environment, and this cannot be excluded. Since these impurities are known to anyone skilled in normal manufacturing processes, the contents of all of them will not be specifically mentioned in this specification.

[0024] The non-oriented electrical steel sheet of the present invention may further contain one or more of Nb: 0.005% or less and V: 0.005% or less.

[0025] Nb: 0.005% or less Nb combines with C, N, etc. to form fine nitrides, which serve to hinder magnetic domain movement, so its upper limit is limited to 0.005%. More specifically, the Nb content is preferably 0.0001 to 0.005%. Even more specifically, the Nb content is preferably 0.0005 to 0.003%.

[0026] V:0.005% or less V combines with C, N, etc. to form fine nitrides, which serve to hinder magnetic domain movement, so its upper limit is limited to 0.005%. More specifically, the V content may be 0.0001 to 0.005%. Even more specifically, the V content may be 0.0005 to 0.003%.

[0027] The non-oriented electrical steel sheet of the present invention may further contain one or more of Cr: 0.01 to 0.5%, Ni: 0.05% or less, Cu: 0.005 to 0.2%, and Zn: 0.01% or less.

[0028] Cr: 0.01 to 0.5% Cr plays a role in increasing resistivity and improving iron loss. If the Cr content is less than 0.01%, the effect of increasing resistivity may be insufficient. If the Cr content exceeds 0.5%, there is a risk of a decrease in magnetic flux density. More specifically, the Cr content is preferably 0.02 to 0.3%.

[0029] Ni: 0.05% or less Ni reacts with impurity elements to form fine sulfides, carbides, and nitrides, which have a detrimental effect on magnetic properties, so its upper limit is limited to 0.05%. More specifically, the Ni content can be 0.0001 to 0.050%. Even more specifically, the Ni content should be 0.001 to 0.030%.

[0030] Cu: 0.005 to 0.2% Cu plays a role in forming sulfides together with Mn. If the Cu content is less than 0.005%, fine (Cu Mn)S precipitates, which can deteriorate magnetic properties. If the Cu content exceeds 0.2%, high-temperature brittleness occurs, which can lead to cracks during continuous casting and hot rolling. More specifically, the Cu content should be 0.010 to 0.1%.

[0031] Zn: 0.01% or less Zn acts as an impurity and can deteriorate magnetic properties, so its upper limit is set to 0.01%. More specifically, the Zn content is preferably 0.0001 to 0.01%. Even more specifically, the Zn content is preferably 0.001 to 0.008%.

[0032] The non-oriented electrical steel sheet of the present invention may further contain one or more of Mo: 0.03% or less, B: 0.0050% or less, Ca: 0.005% or less, and Mg: 0.005% or less.

[0033] These react with the unavoidably contained C, S, N, etc. to form fine carbides, nitrides, or sulfides, which can adversely affect the magnetic properties, so it is advisable to set the upper limit as above.

[0034] The non-oriented electrical steel sheet of the present invention may further contain one or more of Bi, Pb, Ge and As in an amount of 0.20% or less (excluding 0%), respectively or in total.

[0035] When the above elements are further added, they segregate at the grain boundaries, alleviating stress concentration at the grain boundaries during cold rolling and reducing the stress concentration during the subsequent recrystallization annealing process. <111> / / Improves magnetic flux density by suppressing recrystallization of ND-oriented crystal grains. When these elements are added appropriately, the above effects can be further enhanced. However, excessive addition can cause significant segregation, suppressing crystal grain growth and potentially deteriorating magnetic flux density and core loss. More specifically, the alloy may contain one or more of Bi, Pb, Ge, and As in an amount of 0.0001 to 0.20%, each or their combined amount. Even more specifically, the alloy may contain one or more of Bi, Pb, Ge, and As in an amount of 0.001 to 0.10%, each or their combined amount.

[0036] In a non-oriented electrical steel sheet according to one embodiment of the present invention, the average size of the MnS-based precipitates is preferably 0.5 μm or more. If the average size of the MnS-based precipitates is less than 0.5 μm, there is a drawback in that the magnetic properties deteriorate. The average size of the MnS-based precipitates is more preferably 0.7 μm or more. Since a larger average size of the MnS-based precipitates is preferable, the present invention does not particularly limit the upper limit of the average size of the MnS-based precipitates. However, the upper limit of the average size of the MnS-based precipitates may be, for example, 1.2 μm.

[0037] In addition, in the non-oriented cold-rolled steel sheet of the present invention, the fraction of precipitates having an average size of 3 μm or more is preferably 5 area % or less relative to the total precipitates. If the fraction of precipitates having an average size of 3 μm or more exceeds 5 area % relative to the total precipitates, the grain growth rate becomes excessively large during the final annealing process, making it difficult to ensure an optimal grain size, resulting in a disadvantage of deteriorating iron loss. Meanwhile, in the present invention, the fraction of precipitates having an average size of 3 μm or more relative to the total precipitates is advantageously low, so there is no particular restriction on the lower limit. However, the lower limit of the fraction of precipitates having an average size of 3 μm or more relative to the total precipitates may be, for example, 0.5 area %.

[0038] The non-oriented electrical steel sheet of the present invention provided as described above may have a thickness of 0.1 to 0.25 mm. 50 ) may be 1.74 - 0.028 / t + 0.00135 / t2 (t: thickness of steel plate) Tesla or more, and iron loss (W 10 / 400 ) can be 16.18-1.23 / t+0.061 / t2 (t: thickness of the steel sheet) W / Kg or less. 50 ) is more advantageous, so there is no particular upper limit. However, 50 ) is preferably 1.73 Tesla, for example. 10 / 400 ) is more advantageous as it is smaller, so there is no particular lower limit. 10 / 400 ) may have a lower limit of 7 W / Kg, for example. A method for producing a non-oriented electrical steel sheet according to one embodiment of the present invention will be described below.

[0039] First, a slab satisfying the above-mentioned alloy composition is heated. The slab heating temperature is 1100 to 1180°C. If the slab heating temperature is less than 1100°C, there is a drawback that hot deformation resistance is high and hot rolling is difficult. If the slab heating temperature exceeds 1180°C, there is a drawback that fine precipitates increase and iron loss deteriorates.

[0040] The heated slab is then finish hot-rolled to obtain a hot-rolled sheet. The finish hot-rolling temperature can be 870 to 950°C. If the finish hot-rolling temperature is less than 870°C, the strength of the sheet increases, which can lead to defects such as poor shape during coiling. If the finish hot-rolling temperature exceeds 950°C, the rolling speed must be increased, which can make hot-rolling difficult.

[0041] On the other hand, in the present invention, when economical aspects are taken into consideration, the hot-rolled sheet may not be subjected to the hot-rolled sheet annealing step.

[0042] The hot-rolled sheet is then subjected to a first cold rolling at a cold reduction of 40 to 79% to obtain a first cold-rolled sheet. If the cold reduction is less than 40%, sufficient deformation cannot be applied in the first cold rolling, resulting in a disadvantage of deterioration in magnetic properties after final annealing. If the cold reduction exceeds 79%, the final cold reduction is too low and magnetic properties are deteriorated. Therefore, the cold reduction is preferably in the range of 40 to 79%. The lower limit of the cold reduction is more preferably 50%, and the upper limit of the cold reduction is even more preferably 70%.

[0043] The finish cold rolling temperature during the first cold rolling is preferably 50 to 160°C. If the finish cold rolling temperature during the first cold rolling is less than 50°C, deformation is promoted at low temperatures, and excessive amounts of site are provided, resulting in the formation of fine precipitates and deterioration of magnetic properties. If the finish cold rolling temperature during the first cold rolling is more than 160°C, the diffusion of trace elements in the steel is possible, resulting in an increase in fine precipitates, and the oxide layer formed during cold rolling results in deterioration of magnetic properties after final annealing. Therefore, the finish cold rolling temperature during the first cold rolling may be in the range of 50 to 120°C. The upper limit of the finish cold rolling temperature during the first cold rolling is more preferably 130°C.

[0044] Thereafter, the first cold-rolled sheet is subjected to primary annealing. During the primary annealing, the temperature can be maintained at 900 to 1140°C for 60 to 350 seconds. If the temperature during the primary annealing is less than 900°C, recrystallization cannot be sufficiently performed, resulting in a deterioration in magnetic properties. If the temperature during the primary annealing is higher than 1140°C, the grain size becomes too large, making cold rolling difficult. The lower limit of the temperature during the primary annealing is more preferably 950°C. The upper limit of the temperature during the primary annealing is even more preferably 1100°C. If the holding time during the primary annealing is less than 60 seconds, it is difficult to properly coarsen the precipitates, increasing the distribution of fine precipitates and resulting in a deterioration in magnetic properties after final annealing. If the holding time during the primary annealing is higher than 360 seconds, the precipitates become excessively large and coarse, resulting in a deterioration in magnetic properties after final annealing.

[0045] Thereafter, the first cold-rolled sheet that has undergone the primary annealing is subjected to final cold rolling to obtain a second cold-rolled sheet. In the present invention, the cold reduction rate during the final cold rolling is not particularly limited, and cold rolling can be performed to satisfy the product thickness targeted in the present invention.

[0046] Thereafter, the second cold-rolled sheet is subjected to final annealing. The final annealing is preferably performed at 900 to 1100°C for 50 to 120 seconds. If the final annealing temperature is less than 900°C, the optimum grain size cannot be secured, resulting in poor magnetic properties. If the final annealing temperature exceeds 1100°C, the sheet cannot withstand its own weight at such a high temperature, making continuous annealing impossible or being significantly affected by tension during annealing, resulting in poor magnetic properties. If the final annealing time is less than 50 seconds, the precipitates do not coarsen sufficiently, resulting in the formation of fine precipitates, which results in poor core loss. If the final annealing time exceeds 120 seconds, the precipitates coarsen excessively, increasing the fraction of precipitates 3 μm or larger, which makes it difficult to control the grain size and results in poor magnetic properties. [Example]

[0047] The present invention will be described in more detail below with reference to examples. However, it should be noted that the following examples are intended to illustrate and explain the present invention in more detail, and are not intended to limit the scope of the present invention, as the scope of the present invention is determined by the matters described in the claims and matters that can be reasonably inferred from them.

[0048] (Example) A slab having the alloy composition shown in Table 1 below was heated to 1130°C, and then the heated slab was finish hot rolled at 930°C to obtain a hot-rolled sheet. The hot-rolled sheet was then primarily cold rolled under the conditions shown in Table 2 below to obtain a first cold-rolled sheet. The first cold-rolled sheet was then primarily annealed for 120 seconds under the conditions shown in Table 2 below. The primarily annealed first cold-rolled sheet was then final cold rolled under the conditions shown in Table 2 below to obtain a second cold-rolled sheet, and the second cold-rolled sheet was then final annealed to produce a non-oriented electrical steel sheet.

[0049] The precipitates and electrical properties of the non-oriented cold rolled steel sheets thus produced were measured, and the results are shown in Table 3 below. The average size of the MnS-based precipitates and the fraction of precipitates with an average size of 3 μm or more relative to the total precipitates were measured by SEM in an area of ​​2 mm×2 mm of the non-oriented cold-rolled steel sheet. Magnetic flux density (B 50 ) and iron loss (W 10 / 400 ) was measured by the Epstein method using test pieces processed to a size of 305 mm x 30 mm in the rolling direction and the direction perpendicular to the rolling direction, and the number of pieces was adjusted so that the weight was 400 to 450 g.

[0050] [Table 1]

[0051] [Table 2]

[0052] [Table 3]

[0053] As can be seen from Tables 1 to 3 above, in the case of Examples 1 to 20, as the alloy composition and manufacturing conditions proposed by the present invention are satisfied, excellent magnetic properties are ensured by ensuring the average size of MnS-based precipitates and the proportion of precipitates with an average size of 3 μm or more relative to the total precipitates, which are the targets of the present invention.

[0054] In the case of Comparative Examples 1 to 7, the manufacturing conditions of the present invention were not satisfied, and therefore the average size of the MnS-based precipitates or the percentage of precipitates with an average size of 3 μm or more relative to the total precipitates that the present invention aims to achieve could not be ensured, resulting in a level of deterioration in magnetic properties.

Claims

1. In weight percent, one or more of Si: 3.0 to 5.0%, Mn: 0.1 to 1.4%, Al: 0.3 to 1.3%, P: 0.001 to 0.01%, S: 0.003% or less (excluding 0%), C: 0.005% or less (excluding 0%), N: 0.005% or less (excluding 0%), Ti: 0.005% or less (excluding 0%), Sn: 0.001 to 0.08%, and Sb: 0.001 to 0.08%, with the balance being Fe and other unavoidable impurities. The average size of the MnS-based precipitates is 0.5 μm or more, A non-oriented electrical steel sheet characterized in that the fraction of precipitates having an average size of 3 μm or more is 5 area % or less of the total precipitates.

2. 2. The non-oriented electrical steel sheet according to claim 1, wherein the total content of Sn and Sb is 0.1% or less.

3. The non-oriented electrical steel sheet according to claim 1, further comprising at least one of Nb: 0.005% or less and V: 0.005% or less.

4. The non-oriented electrical steel sheet according to claim 1, further comprising one or more of Cr: 0.01 to 0.5%, Ni: 0.05% or less, Cu: 0.005 to 0.2%, and Zn: 0.01% or less.

5. 2. The non-oriented electrical steel sheet according to claim 1, further comprising one or more of Mo: 0.03% or less, B: 0.0050% or less, Ca: 0.005% or less, and Mg: 0.005% or less.

6. 2. The non-oriented electrical steel sheet according to claim 1, further comprising one or more of Bi, Pb, Ge, and As in an amount of 0.20% or less (excluding 0%), respectively or in a total amount thereof.

7. 2. The non-oriented electrical steel sheet according to claim 1, wherein the non-oriented electrical steel sheet has a thickness of 0.1 to 0.25 mm.

8. 2. The non-oriented electrical steel sheet according to claim 1, wherein the non-oriented electrical steel sheet has a magnetic flux density (B50) of 1.74 - 0.028 / t + 0.00135 / t2 (t: thickness of the steel sheet) Tesla or more.

9. The non-oriented electrical steel sheet has an iron loss (W10 / 400) of 16.18-1.23 / t+0.061 / t ２ 2. The non-oriented electrical steel sheet according to claim 1, wherein (t: thickness of the steel sheet) is W / Kg or less.

10. heating a slab containing, in weight percent, one or more of Si: 3.0 to 5.0%, Mn: 0.1 to 1.4%, Al: 0.3 to 1.3%, P: 0.001 to 0.01%, S: 0.003% or less (excluding 0%), C: 0.005% or less (excluding 0%), N: 0.005% or less (excluding 0%), Ti: 0.005% or less (excluding 0%), Sn: 0.001 to 0.08%, and Sb: 0.001 to 0.08%, with the balance being Fe and other unavoidable impurities; finish hot rolling the heated slab to obtain a hot-rolled sheet; performing a first cold rolling on the hot-rolled sheet at a cold reduction of 40 to 79% to obtain a first cold-rolled sheet; a step of first annealing the first cold-rolled sheet; final cold rolling the first cold-rolled sheet after the primary annealing to obtain a second cold-rolled sheet; and final annealing the second cold-rolled sheet; During the first cold rolling, the finish cold rolling temperature is 50 to 160 ° C., The method for producing a non-oriented electrical steel sheet is characterized in that the final annealing is performed at 900 to 1100°C for 50 to 120 seconds.

11. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the total of Sn and Sb is 0.1% or less.

12. The method for manufacturing a non-oriented electrical steel sheet according to claim 10, wherein the slab further contains at least one of Nb: 0.005% or less and V: 0.005% or less.

13. The method for manufacturing a non-oriented electrical steel sheet according to claim 10, wherein the slab further contains one or more of Cr: 0.01 to 0.5%, Ni: 0.05% or less, Cu: 0.005 to 0.2%, and Zn: 0.01% or less.

14. The method for manufacturing a non-oriented electrical steel sheet according to claim 10, wherein the slab further contains one or more of Mo: 0.03% or less, B: 0.0050% or less, Ca: 0.005% or less, and Mg: 0.005% or less.

15. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the slab further contains one or more of Bi, Pb, Ge, and As in an amount of 0.20% or less (excluding 0%), respectively or in total.

16. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the slab heating temperature is 1100 to 1180°C.

17. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the finish hot rolling temperature is 870 to 950°C.

18. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the primary annealing is performed at a temperature of 900 to 1140°C for 60 to 360 seconds.

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