Non-oriented electrical steel sheet and its manufacturing method

Abstract

An object of the present invention is to provide a non-oriented electrical steel sheet with low high-frequency iron loss and a method for manufacturing the same. [Solution] The present invention relates to a composition containing, by weight %, 3.3 to 4.3% Si, 0.8 to 1.7% Al, 0.3 to 2.0% Mn, 0.03 to 0.5% Cu, 0.01 to 0.1% Sn, and 0.002 to 0.01% S, with the remainder being Fe and other unavoidable impurities, The following relational expression 1 is satisfied: The intensity ratio of the texture (112)[1-31] / texture (112)[1-10] is 2.0 or more, [Relationship 1] 0.02≦Sn×S×100 / Cu≦0.75 The non-oriented electrical steel sheet further contains one or more of C: 0.005% or less, N: 0.005% or less, Ti: 0.005% or less, Nb: 0.005% or less, and V: 0.005% or less.

Description

[Technical Field]

[0001] The present invention relates to a non-oriented electrical steel sheet and a manufacturing method thereof, and more particularly to a non-oriented electrical steel sheet that can be preferably used for motor cores and the like having low high-frequency iron loss, and a manufacturing method thereof. [Background technology]

[0002] Recently, with the increase in disasters due to climate change, countries around the world have announced carbon neutral roadmaps for 2050. Total carbon emissions in 2020 will reach 39 billion tons, of which internal combustion engines will account for 24%, or 9.4 billion tons. Therefore, there is a great demand to achieve carbon neutrality in this sector through the electrification of internal combustion engines. As a result, electrification is rapidly progressing in the mobility sector, with electric vehicles at the forefront. The characteristics required of drive motors in new mobility are increased driving range and higher top speeds. This is directly related to the low iron loss characteristics of electrical steel sheets.

[0003] Generally, to improve the recrystallization texture, grain boundary segregation elements are used to suppress the formation of orientations unfavorable for magnetic properties. However, the use of large amounts of segregation elements increases the brittleness of the steel material, which has the drawback of reducing rolling productivity. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a non-oriented electrical steel sheet having low high-frequency iron loss and a method for manufacturing the same. [Means for solving the problem]

[0005] The present invention provides a non-oriented electrical steel sheet containing, by weight%, 3.3 to 4.3% Si, 0.8 to 1.7% Al, 0.3 to 2.0% Mn, 0.03 to 0.5% Cu, 0.01 to 0.1% Sn, 0.002 to 0.01% S, and the balance being Fe and other unavoidable elements, which satisfies the following relational expression 1, and has an intensity ratio of texture (112)[1-31] / texture (112)[1-10] of 2.0 or more. [Relationship 1] 0.02≦Sn×S×100 / Cu≦0.75

[0006] The non-oriented electrical steel sheet may further contain one or more of C: 0.005% or less, N: 0.005% or less, Ti: 0.005% or less, Nb: 0.005% or less, and V: 0.005% or less.

[0007] The non-oriented electrical steel sheet may further contain one or more of P: 0.1% or less, Cr: 0.01 to 0.5%, Sb: 0.1% or less, Ni: 0.05% or less, and Zn: 0.01% or less.

[0008] The non-oriented electrical steel sheet 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.

[0009] The non-oriented electrical steel sheet may further contain one or more of Bi, Pb, Ge and As in an amount of 0.20% or less (excluding 0%), either individually or in total.

[0010] In the non-oriented electrical steel sheet, the strength of the texture (112)[1-31] ​​may be 2.5 or more, and the strength of the texture (112)[1-10] may be 0.9 or less.

[0011] The non-oriented electrical steel sheet may have a resistivity of 55 μΩcm or more.

[0012] The non-oriented electrical steel sheet may have an iron loss (W10 / 400) of 12.2 W / Kg or less.

[0013] The non-oriented electrical steel sheet may have a magnetic flux density (B50) of 1.66 Tesla or more.

[0014] The present invention includes the steps of heating a slab, which contains, by weight, 3.3 to 4.3% Si, 0.8 to 1.7% Al, 0.3 to 2.0% Mn, 0.03 to 0.5% Cu, 0.01 to 0.1% Sn, and 0.002 to 0.01% S, with the balance being Fe and other inevitable impurities, and which satisfies the following relational expression 1, at 1100 to 1250°C; finish hot rolling the heated slab at 800 to 1000°C to obtain a hot-rolled sheet; cold rolling the hot-rolled sheet at a rolling reduction of 70 to 95% to obtain a cold-rolled sheet; and final annealing the cold-rolled sheet at 950 to 1020°C for 30 to 60 seconds, wherein the annealing furnace entry tension during the final annealing is 0.5 to 1.0 kgf / mm 2 The method for manufacturing a non-oriented electrical steel sheet is to control the holding time in the 600 to 750°C range during heating up to the soaking temperature to 24 seconds or less. [Relationship 1] 0.02≦Sn×S×100 / Cu≦0.75

[0015] The slab may further contain one or more of C: 0.005% or less, N: 0.005% or less, Ti: 0.005% or less, Nb: 0.005% or less, and V: 0.005% or less.

[0016] The slab may further contain one or more of P: 0.1% or less, Cr: 0.01 to 0.5%, Sb: 0.1% or less, Ni: 0.05% or less, and Zn: 0.01% or less.

[0017] The slab 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.

[0018] The slab may further contain one or more of Bi, Pb, Ge and As in an amount of 0.20% or less (excluding 0%), either individually or in total.

[0019] After the step of obtaining the hot-rolled sheet, the method may further include a step of annealing the hot-rolled sheet at 850 to 1150°C.

[0020] The above cold rolling can be carried out once or twice. [Effects of the Invention]

[0021] According to the present invention, a non-oriented electrical steel sheet having low high-frequency iron loss and a method for manufacturing the same can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0022] The inventors have recognized that in order to improve the iron loss of non-oriented electrical steel sheets, resistivity can be increased by using Si, Al, and Mn, which are elements that increase resistivity, and Sn, S, and Cu, which are elements that control segregation, while at the same time appropriately controlling the conditions during final annealing to derive a region in which the texture is improved, thereby making it possible to manufacture non-oriented electrical steel sheets with excellent magnetic properties, and have completed the present invention.

[0023] The non-oriented electrical steel sheet of the present invention will be described below. First, the alloy composition will be described. The contents of the alloy compositions below are in wt % unless otherwise specified.

[0024] Si: 3.3 to 4.3% Si is an element that increases the resistivity of a material and reduces iron loss. If the Si content is less than 3.3%, the effect of improving high-frequency iron loss is slight. If the Si content exceeds 4.3%, the productivity and punchability may be deteriorated due to an increase in hardness. Therefore, the Si content is preferably in the range of 3.3 to 4.3%. The lower limit of the Si content is more preferably 3.35%, and even more preferably 3.40%. The upper limit of the Si content is more preferably 4.25%, and even more preferably 4.20%.

[0025] Al: 0.8 to 1.7% Al is an element that increases the resistivity of a material and reduces iron loss. If the Al content is less than 0.8%, the effect of reducing high-frequency iron loss is not achieved, and fine nitrides are formed, deteriorating magnetic properties. If the Al content exceeds 1.7%, the physical properties of the mold flux may change during the continuous casting process, significantly reducing productivity. Therefore, the Al content is preferably in the range of 0.8 to 1.7%. The lower limit of the Al content is more preferably 0.85%, and even more preferably 0.90%. The upper limit of the Al content is more preferably 1.65%, and even more preferably 1.60%.

[0026] Mn: 0.3 to 2.0% Mn is an element that increases the resistivity of the material, improves core loss, and forms sulfides. If the Mn content is less than 0.3%, MnS precipitates finely, degrading magnetic properties. If the Mn content exceeds 2.0%, it promotes the formation of a

[0111] texture that is unfavorable to magnetic properties, resulting in a rapid decrease in magnetic flux density. Therefore, the Mn content is preferably in the range of 0.3 to 2.0%. The lower limit of the Mn content is more preferably 0.35%, and even more preferably 0.40%. The upper limit of the Mn content is more preferably 1.95%, and even more preferably 1.90%.

[0027] Cu: 0.03 to 0.5% Cu plays a role in forming sulfides together with Mn and precipitates with the segregation elements S and Sn to prevent segregation. If the Cu content is less than 0.03%, fine CuMnS precipitates, degrading magnetic properties, and S and Sn form fine precipitates to prevent segregation. If the Cu content exceeds 0.5%, high-temperature brittleness occurs, causing cracks during continuous casting and hot rolling. Therefore, the Cu content is preferably in the range of 0.03 to 0.5%. The lower limit of the Cu content is more preferably 0.04%, and even more preferably 0.05%. The upper limit of the Cu content is more preferably 0.45%, and even more preferably 0.40%.

[0028] Sn: 0.01 to 0.1% Sn is an element that segregates or precipitates at grain boundaries when annealing conditions are appropriately controlled. Furthermore, the Sn may precipitate together with Cu to form an intermetallic compound, or may precipitate as a sulfide. If the Sn content is less than 0.01%, the grain boundary segregation or precipitation effect is difficult to achieve. If the Sn content exceeds 0.1%, the Sn precipitates as an intermetallic compound or sulfide, deteriorating the magnetic properties. Therefore, the Sn content is preferably in the range of 0.01 to 0.1%. The lower limit of the Sn content is more preferably 0.02%, and even more preferably 0.03%. The upper limit of the Sn content is more preferably 0.09%, and even more preferably 0.08%.

[0029] S: 0.002 to 0.01% S is an element that segregates or precipitates at grain boundaries when annealing conditions are appropriately controlled. Furthermore, the S may precipitate together with Cu to form an intermetallic compound, or may precipitate as a sulfide. If the S content is less than 0.002%, the grain boundary segregation or precipitation effect is not sufficiently achieved. If the S content exceeds 0.01%, the S precipitates as an intermetallic compound or sulfide, deteriorating the magnetic properties. Therefore, the S content is preferably in the range of 0.002 to 0.01%. The lower limit of the S content is more preferably 0.0025%, even more preferably 0.0030%, and most preferably 0.0035%. The upper limit of the S content is more preferably 0.009%, and even more preferably 0.008%.

[0030] 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, not all of the contents of these impurities will be specifically mentioned in this specification.

[0031] The non-oriented cold rolled steel sheet of the present invention may further contain one or more of C: 0.005% or less, N: 0.005% or less, Ti: 0.005% or less, Nb: 0.005% or less, and V: 0.005% or less.

[0032] C: 0.005% or less C reacts with N, Ti, Nb, V, etc. to form fine carbides, which play a role in inhibiting grain growth and magnetic domain migration, so its upper limit is limited to 0.005%. More specifically, the C content may be 0.0001 to 0.005%. Even more specifically, the C content may be 0.0005 to 0.003%.

[0033] N: 0.005% or less N combines with Ti, Nb, V, etc. to form nitrides, which reduces grain growth, so its upper limit is limited to 0.005%. More specifically, the N content may be 0.0001 to 0.005%. Even more specifically, the N content may be 0.0005 to 0.003%.

[0034] Ti: 0.005% or less Ti combines with C, N, O, etc. to form fine nitrides or oxides, which plays a role in preventing magnetic domain movement, so the upper limit is limited to 0.005%. More specifically, the Ti content may be 0.0001 to 0.005%. Even more specifically, the Ti content may be 0.0005 to 0.003%.

[0035] 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 may be 0.0001 to 0.005%. Even more specifically, the Nb content may be 0.0005 to 0.003%.

[0036] 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%.

[0037] The non-oriented cold rolled steel sheet of the present invention may further contain one or more of P: 0.1% or less, Cr: 0.01 to 0.5%, Sb: 0.1% or less, Ni: 0.05% or less, and Zn: 0.01% or less.

[0038] P:0.1% or less P acts as a grain boundary segregating element and can delay recrystallization, deteriorating strength uniformity in the rolling direction and the direction perpendicular to the rolling direction, so its upper limit is limited to 0.1%. More specifically, the P content may be 0.0001 to 0.1%. Even more specifically, the P content may be 0.001 to 0.05%.

[0039] 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%, the magnetic flux density may decrease. More specifically, the Cr content may be 0.02 to 0.3%.

[0040] Sb: 0.1% or less Sb is an element that segregates at grain boundaries, suppressing the diffusion of nitrogen through the grain boundaries, suppressing the {111} texture that is detrimental to magnetic properties, and increasing the advantageous {100} texture, thereby improving magnetic properties. If the Sb content exceeds 0.1%, it inhibits grain growth, reducing magnetic properties and deteriorating rolling properties. More specifically, the Sb content can be 0.001 to 0.1%. Even more specifically, the Sb content can be 0.005 to 0.08%.

[0041] 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 the upper limit is limited to 0.05%. More specifically, the Ni content may be 0.0001 to 0.050%. Even more specifically, the Ni content may be 0.001 to 0.030%.

[0042] Zn: 0.01% or less Zn acts as an impurity and can deteriorate magnetic properties, so its upper limit is limited to 0.01%. More specifically, the Zn content can be 0.0001 to 0.01%. Even more specifically, the Zn content can be 0.001 to 0.008%.

[0043] The non-oriented cold rolled 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.

[0044] These react with the unavoidably contained C, S, N, etc. to form fine carbides, nitrides, or sulfides, which can have a negative effect on magnetic properties, so the upper limit can be set as described above.

[0045] The non-oriented cold rolled 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%), either individually or in total.

[0046] When the above-mentioned elements are further added, they segregate at the grain boundaries, alleviating stress concentration at the grain boundaries during cold rolling and allowing the steel to be recrystallized in 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-mentioned effects can be further enhanced. However, excessive addition can cause significant segregation, suppressing crystal grain growth, and actually degrading 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.

[0047] The non-oriented cold rolled steel sheet of the present invention preferably satisfies the above-mentioned alloy composition and also satisfies the following relational expression 1. [Relationship 1] 0.02≦Sn×S×100 / Cu≦0.75

[0048] Sn, S, and Cu are elements that control segregation, and by appropriately controlling the final annealing conditions, it is possible to control the intensity ratio of the texture (112)[1-31] / texture (112)[1-10]. If the value of Sn×S×100 / Cu is less than 0.02, the Cu content relative to Sn and S is high, making segregation difficult. If the value of Sn×S×100 / Cu exceeds 0.75, excessive segregation occurs, resulting in deterioration of magnetic properties. The lower limit of the value of Sn×S×100 / Cu is more preferably 0.025, and even more preferably 0.03. The upper limit of the value of Sn×S×100 / Cu is more preferably 0.70, and most preferably 0.65.

[0049] In the non-oriented electrical steel sheet of the present invention, the intensity ratio of the texture (112)[1-31] / texture (112)[1-10] is preferably 2.0 or more. Even in the same (112) plane, the magnetic property is improved when the intensity of the texture corresponding to the [1-31] ​​direction is higher than that of the [1-10] direction. If the intensity ratio of the texture (112)[1-31] / texture (112)[1-10] is less than 2.0, the magnetic property improvement effect is insufficient. The intensity ratio of the texture (112)[1-31] / texture (112)[1-10] is more preferably 2.2 or more, even more preferably 2.4 or more, and most preferably 2.6 or more. In the present invention, however, the higher the intensity ratio of the texture (112)[1-31] / texture (112)[1-10], the more advantageous it is, so there is no particular upper limit. However, the upper limit of the intensity ratio of the texture (112)[1-31] / texture (112)[1-10] may be, for example, 6.0.

[0050] In the non-oriented electrical steel sheet, the strength of the texture (112)[1-31] ​​may be 2.5 or more, and the strength of the texture (112)[1-10] may be 0.9 or less. By satisfying these conditions, magnetic properties can be improved. The strength of the texture (112)[1-31] ​​is more preferably 2.7 or more, even more preferably 2.9 or more, and most preferably 3.1 or more. The strength of the texture (112)[1-10] is more preferably 0.7 or less, and even more preferably 0.5 or less. In the present invention, the higher the strength of the texture (112)[1-31], the more advantageous it is, so there is no particular upper limit. However, the upper limit of the strength of the texture (112)[1-31] ​​may be 6.0, for example. Furthermore, the lower the strength of the texture (112)[1-10], the more advantageous it is, so there is no particular lower limit. However, the lower limit of the strength of the texture (112)[1-10] may be, for example, 0.2.

[0051] The non-oriented electrical steel sheet of the present invention provided as described above may have a resistivity of 55 μΩcm or more, an iron loss (W10 / 400) of 12.2 W / kg or less, and a magnetic flux density (B50) of 1.66 Tesla or more. In the present invention, the lower the resistivity and iron loss (W10 / 400), the more advantageous they are, so there are no particular restrictions on their lower limits. Meanwhile, the iron loss (W10 / 400) and magnetic flux density (B50) are based on a steel sheet thickness of 0.25 mm.

[0052] The method for producing a non-oriented electrical steel sheet according to the present invention will be described below.

[0053] First, a slab satisfying the above-described alloy composition and Relational Formula 1 is heated at 1100 to 1250°C. If the slab heating temperature is less than 1100°C, the holding time is too long to bring the entire slab to the same temperature, resulting in reduced productivity. If the slab heating temperature exceeds 1250°C, inclusions formed during continuous casting remelt and precipitate finely during the hot rolling process, resulting in a deterioration in magnetic properties. Therefore, the slab heating temperature is preferably in the range of 1100 to 1250°C. The lower limit of the slab heating temperature is more preferably 1110°C, even more preferably 1120°C, and most preferably 1130°C. The upper limit of the slab heating temperature is more preferably 1240°C, even more preferably 1230°C, and most preferably 1220°C.

[0054] The heated slab is then finish hot rolled at 800 to 1000°C to obtain a hot-rolled sheet. If the finish hot rolling temperature is less than 800°C, the temperature during hot rolling is too low, making it impossible to roll to the desired thickness. If the finish hot rolling temperature exceeds 1000°C, it is difficult to control surface oxidation and shape. The lower limit of the finish hot rolling temperature is more preferably 810°C, even more preferably 820°C, and most preferably 830°C. The upper limit of the finish hot rolling temperature is more preferably 990°C, even more preferably 980°C, and most preferably 970°C.

[0055] After obtaining the hot-rolled sheet, the hot-rolled sheet may be annealed at 850 to 1150°C. The hot-rolled sheet annealing process can increase the crystal orientation advantageous for magnetic properties. If the hot-rolled sheet annealing temperature is less than 850°C, crystal grains may not grow or may grow finely, resulting in a small synergistic effect of magnetic flux density. If the hot-rolled sheet annealing temperature exceeds 1150°C, the magnetic properties may deteriorate and rolling workability may be impaired due to sheet deformation. Therefore, the hot-rolled sheet annealing temperature may be in the range of 850 to 1150°C. The lower limit of the hot-rolled sheet annealing temperature is more preferably 870°C, even more preferably 890°C, and most preferably 910°C. The upper limit of the hot-rolled sheet annealing temperature is more preferably 1140°C, even more preferably 1130°C. Alternatively, the hot-rolled sheet annealing may be omitted.

[0056] The hot-rolled sheet is then cold-rolled at a rolling reduction of 70 to 95% to obtain a cold-rolled sheet. If the cold rolling reduction is less than 70%, there is a drawback in that the deformation structure is non-uniform, resulting in a large magnetic deviation in the final product. If the cold rolling reduction exceeds 95%, there is a drawback in that a texture unfavorable to magnetic properties develops, which may result in a deterioration in the magnetic properties of the final product. Therefore, the cold rolling reduction is preferably in the range of 70 to 95%. The lower limit of the cold rolling reduction is more preferably 72%, even more preferably 74%, and most preferably 76%. The upper limit of the cold rolling reduction is more preferably 93%, even more preferably 91%, and most preferably 89%. The cold rolling can be performed once or twice to obtain the target thickness.

[0057] The cold-rolled sheet is then subjected to final annealing by soaking at 950 to 1020°C for 30 to 60 seconds. If the soaking temperature is less than 950°C, grain growth will not occur at an appropriate level, and the magnetic property will not be improved. If the soaking temperature exceeds 1020°C, defects such as microdents will increase on the surface, increasing grain growth and degrading high-frequency iron loss. The lower limit of the soaking temperature is more preferably 955°C, even more preferably 960°C, and most preferably 965°C. The upper limit of the soaking temperature is more preferably 1015°C, even more preferably 1010°C, and most preferably 1005°C. If the soaking time is less than 30 seconds, the grain size will not grow sufficiently, resulting in poor magnetic properties. If the soaking time exceeds 60 seconds, the grains will become excessively large. The lower limit of the soaking time is more preferably 32 seconds, even more preferably 34 seconds, and most preferably 36 seconds. The upper limit of the soaking time is more preferably 59 seconds, even more preferably 58 seconds, and most preferably 57 seconds.

[0058] During the final annealing, the tension at the entrance of the annealing furnace is 0.5 to 1.0 kgf / mm 2 It is preferable to control the holding time in the 600 to 750°C range during heating to the soaking temperature to 24 seconds or less. When an appropriate tension is applied at the inlet side of the annealing furnace, grain boundary segregation is promoted, and magnetic properties can be improved. The tension at the inlet side of the annealing furnace is 0.5 kgf / mm 2 If the tension at the inlet side of the annealing furnace is less than 1.0 kgf / mm, it is difficult to control the deviation of the strip during continuous annealing. 2 If the tension exceeds 0.55 kgf / mm, the formation of a texture unfavorable to magnetic properties is promoted. 2 More preferably, it is 0.6 kgf / mm 2 More preferably, it is 0.65 kgf / mm 2 The upper limit of the annealing furnace entry tension is 0.95 kgf / mm 2 More preferably, it is 0.90 kgf / mm 2More preferably, it is 0.85 kgf / mm 2 It is most preferable that the temperature range is 600 to 750°C. The annealing furnace entry tension can be based on the tension applied to the bridle roll. The 600 to 750°C range is a temperature range in which grain recovery and recrystallization actively occur, and in the present invention, it is preferable to minimize the time spent in this range. This promotes segregation at grain boundaries and improves the texture. If the holding time exceeds 24 seconds, it may be difficult to fully achieve the above-mentioned effects. The holding time is more preferably 22 seconds or less, and even more preferably 20 seconds or less. In the present invention, the shorter the holding time, the more advantageous it is, so there is no particular restriction on the lower limit. However, the lower limit of the holding time may be 10 seconds, for example. [Example]

[0059] 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.

[0060] (Example) A slab (C, N, Ti: 0.003%) having the alloy composition shown in Table 1 below was heated to 1150°C, and then the heated slab was finish hot-rolled at 850°C to obtain a hot-rolled sheet with a thickness of 2.0 mm. The hot-rolled sheet was then annealed at 1100°C for 4 minutes and pickled. The hot-rolled sheet was then cold-rolled at a reduction of 87.5% to obtain a cold-rolled sheet with a thickness of 0.25 mm. This was then final-annealed under the conditions shown in Table 2 below to produce a non-oriented electrical steel sheet. The conditions shown in Table 2 below were based on the surface temperature of the steel sheet.

[0061] The strength of the texture (112)[1-31] ​​and the strength of the texture (112)[1-10] were measured for the non-oriented electrical steel sheets manufactured in this manner, and the resistivity, core loss (W10 / 400) and magnetic flux density (B50) were also measured. The results are shown in Table 3 below.

[0062] The intensity of the texture (112)[1-31] ​​and the intensity of the texture (112)[1-10] were measured using SEM-EBSD.

[0063] The resistivity can be calculated using the following formula 1. [Formula 1]13.25+11.3×([Si]+[Al]+[Mn] / 2)

[0064] Iron loss (W10 / 400) and magnetic flux density (B50) were measured using a single sheet tester based on the JIS standard.

[0065] [Table 1]

[0066] [Table 2]

[0067] [Table 3]

[0068] As can be seen from Tables 1 to 3 above, in the case of Examples 1 to 11, which satisfy the alloy compositions and manufacturing conditions proposed by the present invention, low high-frequency iron loss is ensured by satisfying the intensity ratio of texture (112)[1-31] / texture (112)[1-10] proposed by the present invention.

[0069] In the cases of Comparative Examples 1 to 13, the alloy compositions or manufacturing conditions proposed by the present invention were not satisfied, and it was found that the high-frequency iron loss deteriorated because the intensity ratio of texture (112)[1-31] / texture (112)[1-10] proposed by the present invention was not satisfied.

Claims

1. The alloy contains, by weight, 3.3 to 4.3% Si, 0.8 to 1.7% Al, 0.3 to 2.0% Mn, 0.03 to 0.5% Cu, 0.01 to 0.1% Sn, and 0.002 to 0.01% S, with the balance being Fe and other inevitable impurities; The following relational expression 1 is satisfied: A non-oriented electrical steel sheet characterized in that the strength ratio of texture (112) [1-31] / texture (112) [1-10] is 2.0 or more. [Relationship 1] 0.02≦Sn×S×100 / Cu≦0.75

2. 2. The non-oriented electrical steel sheet according to claim 1, further comprising one or more of C: 0.005% or less, N: 0.005% or less, Ti: 0.005% or less, Nb: 0.005% or less, and V: 0.005% or less.

3. The non-oriented electrical steel sheet according to claim 1, further comprising one or more of P: 0.1% or less, Cr: 0.01 to 0.5%, Sb: 0.1% or less, Ni: 0.05% or less, and Zn: 0.01% or less.

4. 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.

5. 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%), each or a total amount of 0.20% or less (excluding 0%).

6. The non-oriented electrical steel sheet according to claim 1, characterized in that the strength of the texture (112)[1-31] ​​is 2.5 or more and the strength of the texture (112)[1-10] is 0.9 or less.

7. 2. The non-oriented electrical steel sheet according to claim 1, wherein the non-oriented electrical steel sheet has a resistivity of 55 μΩcm or more.

8. 2. The non-oriented electrical steel sheet according to claim 1, wherein the non-oriented electrical steel sheet has an iron loss (W10 / 400) of 12.2 W / Kg or less.

9. The non-oriented electrical steel sheet according to claim 1, wherein the non-oriented electrical steel sheet has a magnetic flux density (B50) of 1.66 Tesla or more.

10. a step of heating a slab containing, by weight, 3.3 to 4.3% Si, 0.8 to 1.7% Al, 0.3 to 2.0% Mn, 0.03 to 0.5% Cu, 0.01 to 0.1% Sn, 0.002 to 0.01% S, with the balance being Fe and other unavoidable impurities, and satisfying the following relational expression 1, at 1100 to 1250°C; finish hot rolling the heated slab at 800 to 1000°C to obtain a hot-rolled sheet; cold-rolling the hot-rolled sheet at a rolling reduction of 70 to 95% to obtain a cold-rolled sheet; A final annealing step of soaking the cold-rolled sheet at 950 to 1020°C for 30 to 60 seconds; During the final annealing, the tension on the inlet side of the annealing furnace is 0.5 to 1.0 kgf / mm ２ and controlling the holding time in the 600 to 750°C range during heating to the soaking temperature to 24 seconds or less. [Relationship 1] 0.02≦Sn×S×100 / Cu≦0.75

11. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the slab further contains one or more of C: 0.005% or less, N: 0.005% or less, Ti: 0.005% or less, Nb: 0.005% or less, and V: 0.005% or less.

12. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the slab further contains one or more of P: 0.1% or less, Cr: 0.01 to 0.5%, Sb: 0.1% or less, Ni: 0.05% or less, and Zn: 0.01% 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 Mo: 0.03% or less, B: 0.0050% or less, Ca: 0.005% or less, and Mg: 0.005% or less.

14. 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%), each or a total amount thereof.

15. The method for manufacturing a non-oriented electrical steel sheet according to claim 10, further comprising the step of annealing the hot-rolled sheet at 850 to 1150°C after the step of obtaining the hot-rolled sheet.

16. The method for producing a non-oriented electrical steel sheet according to claim 10, wherein the cold rolling is performed once or twice.

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