Non-oriented electrical steel sheet

Abstract

The present invention provides a non-oriented electrical steel sheet which has a metal structure that contains, in mass%, specific elements and has a sheet thickness of 0.50 mm or less, in which the metal structure has a transformation temperature Ar3 (°C) of 750 to 1050°C and a recrystallization ratio of 1 to 99%. In any given cross-section of this non-oriented electrical steel sheet, if Sac is the area ratio of (411) crystal grains, Sag is the area ratio of (110) crystal grains, and Sbc is the area ratio occupied by (411) crystal grains in a region where the KAM value is highest to 20%, then Sac > 0.120, Sac > Sbc > Sag and 0.050 > Sag are satisfied.

Description

[Technical field]

[0001] The present disclosure relates to a non-oriented electrical steel sheet. [Background technology]

[0002] Non-oriented electrical steel sheets are used, for example, in the iron cores of motors, and are required to have excellent magnetic properties, such as low core loss and high magnetic flux density, in the average of all directions parallel to the sheet surface (hereinafter sometimes referred to as the "all-around average (all-directional average) within the sheet surface"). Although various technologies have been proposed so far, it is difficult to obtain sufficient magnetic properties in all directions within the sheet surface. For example, even if sufficient magnetic properties can be obtained only in a specific direction within the sheet surface, sufficient magnetic properties may not be obtained in other directions. On the other hand, if high magnetic properties can be secured in continuous regions such as the rolling direction and directions at 45° to the left and right of the rolling direction, even if sufficient magnetic properties cannot be obtained only in a specific direction, it is expected that the number of applicable motor shapes will increase and versatility will increase.

[0003] It is well known that the development of {100} crystal orientation or the reduction of {111} crystal orientation is effective in improving magnetic properties. In order to control such crystal orientation, various studies have been conducted on component systems in which γ→α phase transformation occurs, as shown in Patent Documents 1 to 6. One of the key points in these technologies is to refine the hot-rolled structure. By using a steel composition with a low γ→α phase transformation temperature, accumulating a large amount of strain in the γ phase by low-temperature γ region hot rolling, and then transforming from there, a fine-grained α phase structure is realized at the time of hot-rolling. To achieve this, the addition of γ-stabilizing elements such as Mn, Cu, and Ni is utilized from the viewpoint of lowering the transformation temperature and delaying recovery recrystallization to promote the accumulation of strain. However, Mn is known as a segregation element, and if the content increases, it segregates in the center of the hot-rolled sheet and causes cracks when the hot-rolled sheet is cold-rolled. In addition, the technology that utilizes the γ→α phase transformation is being developed. <011> Since orientation is the main issue, in-plane anisotropy is large, and a new type of crystal orientation control is required. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4029430 [Patent Document 2] Patent No. 6319465 [Patent Document 3] JP 2017-193731 A [Patent Document 4] WO2021 / 095846 [Patent Document 5] Patent Publication No. 2021-080501 [Patent Document 6] JP 2020-100860 A Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above-mentioned problems, the present disclosure has an object to provide a non-oriented electrical steel sheet having a chemical composition in which Mn is suppressed so as to prevent rollability from becoming an issue, and the contents of elements such as Mn, Cu and Ni are optimized, and which has small in-plane anisotropy and excellent magnetic properties can be obtained in a direction at 45° from the rolling direction. [Means for solving the problem]

[0006] (1) A non-oriented electrical steel sheet according to one embodiment of the present disclosure, In mass%, C: 0.0100% or less, Si: 1.50%~4.00%, Sol.Al: 0.0001%~1.0%, S: 0.0100% or less, N: 0.0100% or less, Mn: 0.10% or more, One or more selected from Mn, Ni, and Cu: less than 2.50% in total; Mo: 0.00% to less than 2.50% Cr: 0.00% to less than 2.50%, Ti: 0.000%~0.005%, Nb: 0.000%~0.005%, Sn: 0.000%~0.400%, Sb: 0.000%~0.400%, P: 0.000% to 0.400%, and One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.0000% to 0.0100% in total; The alloy has a chemical composition in which the transformation temperature Ar3 (°C) defined by the following formula (1) is 750 to 1050°C, with the balance being Fe and impurities, where the C content is [C], the Mo content is [Mo], the Cr content is [Cr], the Mn content is [Mn], the Ni content is [Ni], the Cu content is [Cu], the Si content is [Si], the sol.Al content is [sol.Al], and the P content is [P], in mass%, And the plate thickness is 0.50 mm or less, In any cross section, the area ratio of {411} crystal grains is Sac, the area ratio of {110} crystal grains is Sag, and the area ratio of {411} crystal grains in the region up to 20% from the high KAM (Kernel Average Misorientation) value is Sbc. The following relationships are satisfied: Sac>0.120, Sac>Sbc>Sag, and 0.050>Sag. Ar3(℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1)

[0007] (2) A non-oriented electrical steel sheet according to one embodiment of the present disclosure, In mass%, C: 0.0100% or less, Si: 1.50%~4.00%, Sol.Al: 0.0001%~1.0%, S: 0.0100% or less, N: 0.0100% or less, Mn: 0.10% or more, One or more selected from Mn, Ni, Co, Pt, Pb, Au, and Cu: less than 2.50% in total; Mo: 0.00% to less than 2.50% Cr: 0.00% to less than 2.50%, Ti: 0.000%~0.005%, Nb: 0.000%~0.005%, Sn: 0.000%~0.400%, Sb: 0.000%~0.400%, P: 0.000% to 0.400%, and One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.0000% to 0.0100% in total; In mass%, the C content is [C], the Mo content is [Mo], the Cr content is [Cr], and the Mn content is [Mn]. The alloy has a chemical composition in which the transformation temperature Ar3 (°C) defined by the following formula (1) is 750 to 1050°C, with the balance being Fe and impurities, where the Mn content is [Mn], the Ni content is [Ni], the Cu content is [Cu], the Si content is [Si], the sol.Al content is [sol.Al], and the P content is [P]: And the plate thickness is 0.50 mm or less, In any cross section, the area ratio of {411} crystal grains is Sac, the area ratio of {110} crystal grains is Sag, and the area ratio of {411} crystal grains in the region up to 20% from the high KAM (Kernel Average Misorientation) value is Sbc. The following relationships are satisfied: Sac>0.120, Sac>Sbc>Sag, and 0.050>Sag. Ar3(℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1) (3) In the non-oriented electrical steel sheet according to (1) or (2), Magnetic flux density B in the rolling direction 50 is 1.58T or more, and the magnetic flux density B 50 may be 1.70T or more. Effect of the Invention

[0008] According to the above-described aspects of the present disclosure, it is possible to provide a non-oriented electrical steel sheet having a chemical composition in which Mn is suppressed so as to prevent rollability from becoming an issue, and the contents of elements such as Mn, Cu, and Ni are optimized, and which is capable of obtaining excellent magnetic properties in the direction at 45° from the rolling direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present inventors have conducted extensive research to solve the above problems. As a result, they have found that the {411} crystal orientation is developed by the subsequent cold rolling and intermediate annealing, by ensuring rollability by limiting the amount of Mn added, adjusting the composition, and then optimizing the hot rolling conditions to form an appropriate α-processed grain structure at the hot-rolled sheet stage. This {411} crystal orientation is further enriched by strain-induced grain boundary migration (SIBM) caused by final annealing when the intermediate annealed sheet is subjected to skin-pass rolling and then final annealing. It has also been found that enriching the {411} crystal orientation is effective in reducing the in-plane anisotropy of magnetic properties and improving the 45° direction from the rolling direction.

[0010] Based on these findings, the present inventors conducted further intensive research and arrived at the present disclosure.

[0011] Hereinafter, the embodiments of the present disclosure will be described in detail. In this specification, a numerical range expressed using "~" means a range including the numerical values ​​before and after "~" as the lower and upper limits. It is also self-evident that each element of the following embodiments can be combined with each other. Furthermore, in the embodiments of the present disclosure, "non-oriented electrical steel sheet" refers not only to coil-shaped or cut-plate steel sheets, but also to steel sheets processed into specific shapes as materials for products (components) such as motor cores, and further to steel sheets that are laminated after processing to form motor cores.

[0012] First, the chemical composition of the non-oriented electrical steel sheet according to the embodiment of the present disclosure and the steel material used in the manufacturing method thereof will be described. In the following description, the unit of content of each element contained in the non-oriented electrical steel sheet or steel material, "%", means "mass %" unless otherwise specified. In addition, the chemical composition of the non-oriented electrical steel sheet indicates the content when the base material excluding the coating, etc. is taken as 100%. In addition, in the numerical ranges described in stages in this specification, The upper limit value of the above may be replaced by the upper limit value of another stepwise described numerical range, or may be replaced by a value shown in the examples. In the numerical ranges described in stages in this specification, the lower limit value of a certain numerical range may be replaced by the lower limit value of another numerical range described in stages, or may be replaced by a value shown in the examples.

[0013] The non-oriented electrical steel sheet according to this embodiment has a chemical composition in which ferrite-austenite transformation (hereinafter, α-γ transformation) can occur, In mass%, C: 0.0100% or less, Si: 1.50%~4.00%, Sol.Al: 0.0001%~1.0%, S: 0.0100% or less, N: 0.0100% or less, Mn: 0.10% or more, One or more selected from Mn, Ni, and Cu: less than 2.50% in total; Mo: 0.0% to less than 2.5% Cr: 0.0% to less than 2.5% Ti: 0.000% to 0.005% Nb: 0.000% to 0.005% Sn: 0.000%~0.400%, Sb: 0.000%~0.400%, P: 0.000% to 0.400%, and The alloy has a chemical composition comprising one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.0000% to 0.0100% in total, with the contents of C, Si, P, sol. Al, Mn, Mo, Cu, Cr, and Ni satisfying the specified conditions described below, and the balance being Fe and impurities.

[0014] In the non-oriented electrical steel sheet according to this embodiment, one or more elements selected from Mn, Ni, Co, Pt, Pb, Au, and Cu are preferably contained in a total amount of less than 2.50%.

[0015] Examples of impurities include those contained in raw materials such as ores and scraps, and those contained in the manufacturing process.

[0016] (C: 0.0100% or less) C increases iron loss and causes magnetic aging. Therefore, the lower the C content, the better. This phenomenon is prominent when the C content exceeds 0.0100%. For this reason, the C content is set to 0.0100% or less. Reducing the C content also contributes to uniformly improving the magnetic properties in all directions within the plate surface. There is no particular lower limit for the C content, but it is preferably set to 0.0005% or more, taking into account the cost of decarburization during refining.

[0017] (Si: 1.50% to 4.00%) Silicon increases electrical resistance, reduces eddy current loss, reduces iron loss, and increases the yield ratio to improve punching workability into iron cores. If the Si content is less than 1.50%, these effects cannot be fully obtained. Therefore, the Si content is set to 1.50% or more. The Si content is preferably more than 1.80, and more preferably 2.00 or more. On the other hand, if the Si content exceeds 4.00%, the magnetic flux density decreases, punching workability decreases due to an excessive increase in hardness, and cold rolling becomes difficult. Therefore, the Si content is set to 4.00% or less.

[0018] (sol.Al:0.0001%~1.0%) Sol.Al increases electrical resistance, reduces eddy current loss, and reduces iron loss. Sol.Al reduces the magnetic flux density B 50 It also contributes to improving the relative size of the sol.Al. If the sol.Al content is less than 0.0001%, these effects cannot be fully obtained. Furthermore, Al also has the effect of promoting desulfurization during steelmaking. Therefore, the sol.Al content is set to 0.0001% or more. On the other hand, if the sol.Al content exceeds 1.0%, the magnetic flux density decreases and the yield ratio decreases, resulting in a decrease in punching workability. Therefore, the sol.Al content is set to 1.0% or less. Here, the total content of Si and sol. Al is preferably more than 1.80, and more preferably 2.00 or more. Incidentally, sol. Al means acid-soluble Al that is not in the form of an oxide such as Al2O3 and is soluble in acid.

[0019] Here, the magnetic flux density B 50 is the magnetic flux density in a magnetic field of 5000 A / m.

[0020] (S:0.0100% or less) S is not an essential element, and is contained, for example, as an impurity in steel. S inhibits recrystallization and grain growth during annealing by precipitating fine MnS. Therefore, the lower the S content, the better. Such an increase in iron loss and a decrease in magnetic flux density due to the inhibition of recrystallization and grain growth are significant when the S content exceeds 0.0100%. For this reason, the S content is set to 0.0100% or less. There is no particular lower limit for the S content, but it is preferably set to 0.0003% or more in consideration of the cost of desulfurization treatment during refining.

[0021] (N:0.0100% or less) Like C, N deteriorates magnetic properties, so the lower the N content, the better. Therefore, the N content is set to 0.0100% or less. There is no particular lower limit for the N content, but it is preferably set to 0.0010% or more in consideration of the cost of denitrification treatment during refining.

[0022] (One or more selected from Mn, Ni, and Cu: less than 2.50% in total) If the total content of Mn, Ni, and Cu is 2.5% or more, the anisotropy of the magnetic properties increases, so the total content of Mn, Ni, and Cu is less than 2.5%. The reason why the anisotropy increases is not clear, but it is thought to be because it affects slip deformation in the ferrite region and promotes the formation of the {100} orientation and recrystallization. From this point of view, it is preferable that the increase in the content of the alloying elements is 2.3% or less. The lower limit of the total content of Mn, Ni, and Cu is not particularly limited, but may be, for example, 0.10% or more, 0.50% or more, 1.00% or more, or even 2.00% or more.

[0023] (One or more selected from Mn, Ni, Co, Pt, Pb, Au, and Cu: less than 2.50% in total) In addition to the above-mentioned Mn, Ni, and Cu, Co, Pt, Pb, and Au also increase the anisotropy of the magnetic properties, so in this embodiment, it is preferable to keep the total content of these elements below 2.50%. Furthermore, since these elements reduce the magnetic flux density, it is preferable to keep the total content below 2.00%. The lower limit of the total content of Mn, Ni, Co, Pt, Pb, Au, and Cu is not particularly limited, but may be, for example, 0.10% or more, 0.50% or more, 1.00% or more, or even 2.00% or more. In particular, since the alloy cost of Co, Pt, Pb, and Au is high, active addition should be avoided. Furthermore, even considering the control of the Ar3 transformation point, which is one of the features of this embodiment, it is preferable to control the Ar3 transformation point by containing Mn, Ni, and Cu. For this reason, the total amount of Co, Pt, Pb, and Au should be less than 0.5%, more preferably 0.1% or less, and should be kept within the range of unavoidable elements, and there is no need to actively add them (they may be 0%).

[0024] Furthermore, the non-oriented electrical steel sheet and steel material according to the present embodiment further satisfy the following condition as a condition under which the α-γ transformation can occur: That is, when the C content is [C], the Mo content is [Mo], the Cr content is [Cr], the Mn content is [Mn], the Ni content is [Ni], the Cu content is [Cu], the Si content is [Si], the sol.Al content is [sol.Al], and the P content is [P], in mass%, the transformation temperature Ar3 (°C) defined by the following formula (1) is 750 to 1050°C.

[0025] Ar3(℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1)

[0026] If the above formula (1) is not satisfied, even if the α-γ transformation occurs, the transformation point is not in the appropriate temperature range, so sufficient magnetic flux density cannot be obtained even if the manufacturing method described below is applied. If the Ar3 transformation point is less than 750°C, the hot rolling temperature becomes low, so the deformation resistance increases and the load on the rolling mill becomes too large, and the amount of added elements increases, which leads to a decrease in toughness of the hot-rolled sheet and cold-rolled sheet, so this value is set as the lower limit. On the other hand, if the Ar3 transformation point exceeds 1050°C, the hot rolling temperature becomes too high, so extremely high temperature heating is required, which increases the load on the heating furnace, or the composition system does not cause γ→α transformation, so this value is set as the upper limit.

[0027] (Mn: 0.10% or more, the total of one or more selected from Mn, Ni, and Cu, or the total of one or more selected from Mn, Ni, Co, Pt, Pb, Au, and Cu is less than 2.5%) Mn lowers the Ar3 transformation point, and in the component system of the non-oriented electrical steel sheet according to this embodiment, it enables the refinement of crystal grains of the hot-rolled sheet by phase transformation. Mn is an element that increases the electrical resistance of steel and reduces iron loss. Therefore, Mn is contained at 0.10% or more. From this viewpoint, Mn is preferably contained at 0.50% or more. More preferably, it is contained at 1.00% or more. On the other hand, Mn is an element that easily segregates, and if the content increases, not only does it cause cold work cracks due to segregation, but it also reduces the saturation magnetic flux density and prevents an increase in the magnetic flux density of the steel sheet. In addition, MnS is excessively generated, and the cold workability is reduced. Therefore, the Mn content is limited within the above range. Specifically, the upper limit of the Mn content is less than 2.5%, preferably 2.3 mass% or less, and more preferably 2.0 mass%.

[0028] (Cu: The total amount of one or more selected from Mn, Ni, and Cu, or the total amount of one or more selected from Mn, Ni, Co, Pt, Pb, Au, and Cu is less than 2.5%.) Like Mn, Cu is an element that increases the electrical resistance of the steel sheet and reduces iron loss, and is an element that lowers the Ar3 transformation point and enables the refinement of the grain size of the hot-rolled sheet by phase transformation in the chemical composition of the non-oriented electrical steel sheet according to this embodiment. However, if the Cu content is high, it not only adversely affects the formation of texture in annealing after cold rolling due to an increase in recrystallization temperature, and causes embrittlement in the hot state, but also reduces the saturation magnetic flux density and prevents the increase in the magnetic flux density of the steel sheet, so care must be taken. Therefore, the Cu content is limited to less than 2.5%. In addition, by adding Ni in an amount equal to or more than half the Cu content, embrittlement in the hot state caused by Cu can be reduced. In addition, the upper limit of the Cu content is not limited, but may be 1.6 mass% or less, preferably 1.2 mass% or less, and more preferably 1.0 mass% or less. The lower limit of the Cu content is not particularly limited, but may be, for example, 0.01% or more.

[0029] (Ni: The total content of one or more selected from Mn, Ni, and Cu, or the total content of one or more selected from Mn, Ni, Co, Pt, Pb, Au, and Cu is less than 2.5%) Ni, like Mn, increases the electrical resistance of the steel sheet and reduces iron loss. Ni further lowers the A3 transformation point, enabling the crystal grains to be refined by phase transformation in the chemical composition of the non-oriented electrical steel sheet according to this embodiment. However, if the Ni content is too high, not only will the product cost increase because Ni is expensive, but it will also lower the saturation magnetic flux density and prevent an increase in the magnetic flux density of the steel sheet, so it is preferable to take these factors into consideration when designing the content. Therefore, the Ni content is limited to less than 2.5%. In addition, the upper limit of the Ni content is preferably 1.0 mass% or less, and more preferably 0.7 mass% or less. The lower limit of the Ni content is not particularly limited and may be 0%, but may be, for example, 0.01% or more.

[0030] (Mo: 0.0% to less than 2.5%) Mo is an element that lowers the Ar3 transformation point and enables the grain size of the hot-rolled sheet to be refined by phase transformation in the chemical composition of the non-oriented electrical steel sheet according to this embodiment. Therefore, Mo may be contained as necessary, and it is preferable to contain 0.1% or more. On the other hand, when Mo is 2.5% Since a Mo content of more than this amount significantly deteriorates cold workability, the Mo content is set to less than 2.5%.

[0031] (Cr: 0.0% to less than 2.5%) Cr is an element that lowers the Ar3 transformation point and enables the grain size of the hot-rolled sheet to be refined by phase transformation in the chemical composition of the non-oriented electrical steel sheet according to this embodiment, and also has the effect of improving not only strength adjustment and corrosion resistance, but also high-frequency characteristics in particular. Therefore, Cr may be contained as necessary, and it is preferable to contain 0.1% or more. On the other hand, excessive Cr content not only saturates the effect and increases the raw material cost, but also reduces the saturation magnetic flux density and prevents an increase in the magnetic flux density of the steel sheet. For this reason, the Cr content is set to less than 2.5%.

[0032] (Ti: 0.000%~0.005%) Ti, when present as a solid solution or TiN, inhibits recrystallization and contributes to refinement of the austenite grain size. Therefore, Ti may be added as necessary, and it is preferable to add 0.001% or more. On the other hand, if the Ti content exceeds 0.005%, various precipitates such as TiN, TiS, and TiC are generated, which deteriorates the iron loss characteristics, so the Ti content is set to 0.005% or less.

[0033] (Nb: 0.000%~0.005%) Nb, when present in the form of solid solution or NbN, inhibits recrystallization and contributes to refinement of the austenite grain size. Therefore, Nb may be added as necessary, and it is preferable to add 0.001% or more. On the other hand, if the Nb content exceeds 0.005%, various precipitates such as NbN and NbC are generated, which deteriorates the iron loss characteristics, so the content is set to 0.005% or less.

[0034] (Sn:0.000%~0.400%, Sb:0.000%~0.400%, P:0.000%~0.400%) Sn and Sb improve the texture after cold rolling and recrystallization, and increase the magnetic flux density. Therefore, these elements may be added as necessary, but if they are included in excess, they embrittle the steel. Therefore, the Sn content and Sb content are both set to 0.400% or less. Furthermore, P may be added to ensure the hardness of the steel sheet after recrystallization, but if it is included in excess, it will embrittle the steel. Therefore, the P content is set to 0.400% or less.

[0035] In order to impart further effects such as magnetic properties, it is preferable to contain one or more elements selected from the group consisting of 0.020% to 0.400% Sn, 0.020% to 0.400% Sb, and 0.020% to 0.400% P.

[0036] (One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.0000% to 0.0100% in total) Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd react with S in the molten steel during casting of the molten steel to form precipitates of sulfides or oxysulfides, or both. Hereinafter, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd may be collectively referred to as "coarse precipitate forming elements". The particle size of the precipitates of the coarse precipitate forming elements is about 1 μm to 2 μm, which is much larger than the particle size (about 100 nm) of fine precipitates such as MnS, TiN, AlN, TiC, NbC, etc. For this reason, these fine precipitates adhere to the precipitates of the coarse precipitate forming elements, and are less likely to inhibit recrystallization and grain growth during annealing such as intermediate annealing. In order to fully obtain these effects, it is preferable that the total amount of the coarse precipitate forming elements is 0.0005% or more. However, if the total of these elements exceeds 0.0100%, the total amount of sulfides or oxysulfides or both will be excessive, and recrystallization and grain growth during annealing such as intermediate annealing will be inhibited. Therefore, the total content of the coarse precipitate forming elements is set to 0.0100% or less. The upper limit of the total content of the coarse precipitate forming elements may be set to 0.0080% or less, or further to 0.0050% or less.

[0037] In this embodiment, the balance of the chemical composition other than the above may be Fe and impurities. The impurities refer to elements that are mixed in the steel raw materials and / or during the steelmaking process. do.

[0038] The chemical composition is determined by the following method. The chemical composition can be measured by a general analysis method for steel. For example, the chemical composition can be measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Specifically, the chemical composition can be determined by measuring test pieces taken from the steel plate with a specified measuring device under conditions based on a previously prepared calibration curve. C and S can be measured using the combustion-infrared absorption method, and N can be measured using the inert gas fusion-thermal conductivity method. O can be measured using the inert gas fusion-non-dispersive infrared absorption method. If the surface has an insulating coating, it may be mechanically removed using a minitor or the like before being subjected to analysis.

[0039] Next, the metal structure of the non-oriented electrical steel sheet according to this embodiment will be described. Although the details of the manufacturing method will be described later, the non-oriented electrical steel sheet according to this embodiment has a chemical composition in which α-γ transformation can occur.

[0040] Next, the thickness of the non-oriented electrical steel sheet according to this embodiment will be described. The thickness of the non-oriented electrical steel sheet according to this embodiment is 0.50 mm or less. The preferred thickness of the non-oriented electrical steel sheet according to this embodiment is 0.10 to 0.50 mm. Usually, as the thickness decreases, the iron loss decreases, but the magnetic flux density decreases. In view of this, if the thickness is 0.10 mm or more, the iron loss is lower and the magnetic flux density is higher. Furthermore, if the thickness is 0.50 mm or less, low iron loss can be maintained. The lower limit of the thickness is more preferably 0.20 mm, and even more preferably 0.30 mm.

[0041] Next, the strain distribution of the non-oriented electrical steel sheet according to this embodiment will be described. The non-oriented electrical steel sheet according to this embodiment has a strain distribution that allows a high magnetic flux density to be obtained in the direction at 45° from the rolling direction. Specifically, the non-oriented electrical steel sheet according to this embodiment satisfies Sac>0.120, Sac>Sbc>Sag, and 0.050>Sag.

[0042] Next, Sac, Sag and Sbc will be described. Sac is the area ratio of {411} crystal grains in any cross section of a steel sheet after skin-pass rolling, and Sag is the area ratio of {110} crystal grains in any cross section of a steel sheet after skin-pass rolling. When observing any cross section of a steel sheet after skin-pass rolling (a polished surface obtained by polishing 1 / 2 of the steel sheet from the sheet side of the steel sheet), the total area of ​​the cross section is Sall, the area of ​​the {411} crystal grains in the cross section is Sallc, and the area of ​​the {110} crystal grains in the cross section is Sallg, then Sac is expressed as Sac=Sallc / Sall. Sag is expressed as Sag=Sallg / Sall. {411} grains (or {110} grains) are grains that are defined within a tolerance of 10° from the target crystal orientation. In other words, the crystal orientation has a tolerance of ±10° from the target crystal orientation.

[0043] Sbc is the area ratio of {411} crystal grains in a region showing a certain KAM value. Sbc is defined as follows. In the same cross section as above, if the total area of ​​the region in the range of 20% from the side with the high KAM (Kernel Average Misorientation) value is Ssab, and the area occupied by {411} crystal grains in the region in the range of 20% from the side with the high KAM value is Ssabc, Sbc is expressed as Sbc = Ssabc / Ssab.

[0044] The KAM value indicates the difference in orientation between a measurement point and an adjacent measurement point within the same grain (however, if the adjacent measurement points are different crystal grains, the adjacent measurement points are excluded from the calculation of KAM). The KAM value is high in areas with a lot of distortion. By extracting up to 20% of the area with such high KAM values, it is possible to extract only the highly distorted areas. The measurement point is an area made up of any number of pixels. The size of the pixels that make up the measurement point is preferably 0.1 to 1.0 μm in order to accurately determine the KAM value.

[0045] The region up to 20% from the high KAM value side is obtained as follows. First, a histogram showing the frequency distribution of the KAM value in the above cross section is created. This histogram shows the frequency distribution of the KAM value in the above cross section. Next, this histogram is converted into a cumulative histogram. Then, in this cumulative histogram, a range from the high KAM value side to 20% (0-20%) of the cumulative relative frequency is determined. Then, the region (a) having this range of KAM values ​​is defined (mapped) on the above cross section as the "region up to 20% from the high KAM value side". That is, the area of ​​the region (a) defined in this way is Ssab. Next, in the above cross section, a region (b) of {411} crystal grains is defined, and a region (c) where the region (a) and the region (b) overlap is obtained. The area of ​​the region (c) defined in this way is Ssabc.

[0046] Note that Sallc, Sallg, Ssabc, etc. do not strictly indicate the area of ​​the crystal grains in each orientation, but include, for example, the areas of orientations that allow a deviation (tolerance) of up to 10° from each orientation. In other words, the area ratio of crystal grains in a target crystal orientation is the area ratio of crystal grains having a crystal orientation within ±10° from the target crystal orientation.

[0047] The KAM value can be calculated by analyzing the image of the cross section of the sample using software such as OIM Analysis. The maximum KAM value is automatically assigned by the software. In the above explanation, the side with a high KAM value means the side with the highest KAM value in the frequency distribution of the KAM values. For example, in the case of a cumulative histogram with a KAM value of 0 as the origin, the range that occupies 20% of the cumulative relative frequency from the side with a high KAM value is the range of cumulative relative frequency from 1 to 0.8.

[0048] In the non-oriented electrical steel sheet according to this embodiment, the metal structure to be specified is specified in a cross section parallel to the sheet surface of the steel sheet, and is specified by the following procedure. First, the plate is polished so that the 1 / 2 thickness position is exposed, and the polished surface (polished surface polished 1 / 2 from the plate side of the steel plate) is observed using SEM with EBSD (Electron Back Scattering Diffraction) at an accelerating voltage of 25 kV and a magnification of 1000x. The observation field is 500 μm x 500 μm. Observation may be performed at several locations divided into several small sections. The step interval during measurement is 0.3 μm. The following types of areas and KAM (Kernel Average Misorientation) values ​​are obtained from the EBSD observation data using standard methods. The area of ​​each orientation can be calculated by calculating the IPF (Inverse Pole Figure) from the EBSD observation field. The KAM value can be calculated by calculating the orientation difference between measurement points using software such as OIM Analysis. In this disclosure, OIM Analysis 7.3 is used, and the tolerance for entering the KAM value is set to 5° or less of orientation difference with adjacent pixels, and the nearest neighbor (1 st The average of the calculated misorientation values ​​between the measurement points of the neighbors is used as the KAM value. Note that the "Set zero point kernel to maximum misorientations" setting should be left as the default and checked.

[0049] In the non-oriented electrical steel sheet according to this embodiment, when Sac is 0.120 or less, excellent magnetic properties cannot be obtained even if grain growth occurs while satisfying the relationships Sac>Sbc>Sag and 0.050>Sag. Therefore, Sac satisfies Sac>0.120.

[0050] The above inequality Sac>Sag indicates that the proportion of {411} grains is greater than that of {110} grains. During annealing after the skin pass, both {411} grains and {110} grains tend to grow. Here, the magnetic properties of {411} grains are superior to those of {110} grains in the 45° direction from the rolling direction, so the {411} grains It is more preferable to have more of the above.

[0051] Next, the relationship Sac>Sbc means that the {411} grains have relatively few regions with high strain. It is known that grains with low strain eat away at grains with high strain during annealing after skin pass rolling. Therefore, this inequality means that {411} grains tend to grow.

[0052] In the non-oriented electrical steel sheet according to the present embodiment, {411} crystal grains grow, and the steel sheet has a structure in which {411} crystal grains can easily grow, so the area ratio Sag of {110} crystal grains is less than 0.05. If the area ratio Sag of {110} crystal grains is 0.05 or more, excellent magnetic properties cannot be obtained. The reason for making Sbc>Sag is that the magnetic properties in the 45° direction from the rolling direction are improved when the proportion of {411} crystal grains in the high strain region is higher than the proportion of {110} crystal grains.

[0053] Next, the magnetic properties of the non-oriented electrical steel sheet according to this embodiment will be described. The non-oriented electrical steel sheet according to this embodiment refers to a final annealed sheet, and among the three directions that form angles of 0°, 45°, and 90° with the rolling direction, the magnetic properties in the 45° direction are the best. In this embodiment, the magnetic properties in the 45° direction are the average value of the magnetic properties in the two directions that form angles of +45° and -45° with the rolling direction.

[0054] When the magnetic flux density of the non-oriented electrical steel sheet according to this embodiment was measured, the magnetic flux density B 50 is 1.58T or more, and the magnetic flux density B 50 is preferably 1.70T or more.

[0055] In the non-oriented electrical steel sheet according to this embodiment, the magnetic flux density B 50 The value of B 50L , magnetic flux density B at 45° to the rolling direction 50 The value of B 50D , magnetic flux density B at 90° to the rolling direction 50 The value of B 50C Then, B 50D is relatively high, followed by B50L High, B 50C The magnetic flux density is anisotropic, with the

[0056] The magnetic flux density can be measured by cutting a 55 mm square sample from a direction at 45° or 0° to the rolling direction, and using a single sheet magnetic measurement device.

[0057] Next, an example of a method for producing the non-oriented electrical steel sheet according to the present embodiment will be described. The non-oriented electrical steel sheet according to the present embodiment is obtained by a production method including a hot rolling step, a cold rolling step, an intermediate annealing step, a skin pass rolling step, and a final annealing step. Preferred conditions for each step will now be described. Hereinafter, in this embodiment, the Ar3 temperature is the transformation temperature Ar3 (° C.) defined by the above formula (1).

[0058] (Hot rolling process) In the hot rolling process, hot rolling is performed on the steel material satisfying the above-mentioned chemical composition to produce a hot rolled steel sheet. The hot rolling process includes a heating process and a rolling process.

[0059] The steel material is, for example, a slab produced by normal continuous casting, and the steel material having the above-mentioned composition is produced by a known method. For example, molten steel is produced in a converter or electric furnace. The produced molten steel is subjected to secondary refining in a degassing facility or the like to produce molten steel having the above-mentioned chemical composition (the chemical composition does not change substantially in the subsequent steps). The molten steel is cast into a slab by a continuous casting method or an ingot casting method. The cast slab may be subjected to blooming rolling.

[0060] In the heating process, the steel material having the above chemical composition is heated to 1000-1200℃. Specifically, the steel material is charged into a heating furnace or a soaking furnace and heated in the furnace. The holding time at the heating temperature in the heating furnace or the soaking furnace is not particularly limited, but is, for example, 30 to 200 hours.

[0061] In the rolling process, the steel material heated in the heating process is rolled in multiple passes to produce a hot-rolled steel sheet. Here, "pass" means that the steel sheet passes through one rolling stand having a pair of work rolls and is subjected to rolling reduction. For example, hot rolling may be performed by tandem rolling using a tandem rolling mill including multiple rolling stands arranged in a row (each rolling stand having a pair of work rolls) to perform multiple passes, or by reverse rolling having a pair of work rolls to perform multiple passes. From the viewpoint of productivity, it is preferable to perform multiple rolling passes using a tandem rolling mill.

[0062] In the rolling process (rough rolling and finish rolling), the above-mentioned steel material is heated and hot-rolled. The steel material is, for example, a slab manufactured by normal continuous casting. The slab is heated to the Ar3 temperature or higher, which is a temperature range in which the steel structure becomes a γ phase. Hot rolling is started in a temperature range in which the steel structure becomes a γ phase (hereinafter, this temperature range may be referred to as the γ range), and is performed in the γ range except for a necessary number of passes including the final pass of the finish rolling, and is completed by performing a necessary number of passes including the final pass in a temperature range in which the α phase exists in the steel structure (hereinafter, this temperature range may be referred to as the α range). In general, the front to middle stages of rough rolling and finish rolling are performed in the γ range, and the rear stage of finish rolling is performed in the α range. In this embodiment, the total reduction in the temperature range from the Ar3 temperature or higher to Ar3+20°C or lower immediately before the final rolling in the α range is set to 10% or more. Furthermore, the reduction ratio in the temperature range of the finish rolling temperature FT or higher and lower than the Ar3 temperature is set to 15% or more in total, taking into consideration the case where rolling is performed in multiple passes. The finish rolling temperature FT refers to the surface temperature of the hot-rolled steel sheet immediately after finish rolling. The lower limit of the finish rolling temperature FT is not particularly limited, but is set to, for example, Ar3 temperature -100°C or more.

[0063] Rolling at temperatures above Ar3+20°C just before the final rolling in the α region has almost no effect on the grain size of the deformed γ grains before the phase transformation, and coarse deformed α grains are formed after the transformation, which is unrelated to the accumulation of the {411} crystal orientation in the final product. If the rolling reduction ratio in the temperature range of Ar3 temperature or higher and Ar3+20°C or lower immediately before the final rolling in the α region is less than 10%, the accumulation of strain in the worked γ grains before the phase transformation will be insufficient, resulting in the formation of coarse worked α grains, which will make it difficult for the final product to accumulate in the {411} crystal orientation. The rolling reduction ratio in the temperature range of Ar3 temperature or higher and Ar3+20°C or lower is preferably 15% or higher. There is no upper limit to the total rolling reduction ratio, but since a reduction ratio exceeding 40% places too much strain on the rolling machine, it is preferable to set the upper limit at 40%, and more preferably at 30% or lower. If the total reduction in the temperature range from the finish rolling temperature FT to the Ar3 temperature in the final α region is less than 15%, the processed α grains after phase transformation from the processed γ grains cannot sufficiently accumulate processing strain in the α region, and accumulation in the {411} crystal orientation in the final product is difficult. The reduction in the temperature range from the finish rolling temperature FT to the Ar3 temperature is preferably 20% or more. There is no upper limit to the total reduction, but since a reduction exceeding 40% places too much strain on the rolling mill, it is preferable to set the upper limit at 40%, and more preferably at 30% or less. The total rolling reduction at a finish rolling temperature of FT or higher and lower than Ar3-20°C is preferably more than 10%. In this embodiment, the reduction ratio RR0 in the hot rolling is defined as follows. Reduction rate RR0 (%) = (1 - thickness after rolling in the relevant temperature range in hot rolling / thickness before rolling in the relevant temperature range in hot rolling) x 100

[0064] The lower limit temperature for rolling in the α region is not particularly limited, but since a lower rolling temperature increases the load on the rolling mill, it is preferable to set the lower limit temperature to 600° C. or higher. The rolling temperature may fluctuate above or below the specified judgment temperature (Ar3 temperature or Ar3+20°C) during the rolling pass due to the competition between the temperature drop caused by roll contact and cooling lubricant and the temperature rise caused by processing. In this embodiment, such a situation is handled as follows. In a rolling pass, it is assumed that the temperature at the entry side is TPI (℃), the thickness at the entry side is TCI (mm), the temperature at the exit side is TPO (℃), and the thickness at the exit side is TCO (mm), and furthermore that the thickness change and temperature change during the rolling pass change while maintaining a simple linear relationship. In other words, if the thickness at a specific point in time during a rolling pass is TCa (mm) and the temperature is TPa (℃), it is assumed that the following formula always holds true during the rolling pass. (TCa-TCO) / (TCI-TCO)=(TPa-TPO) / (TPI-TPO) This makes it possible to determine the plate thickness at that time point even when the prescribed judgment temperature in this manufacturing method (Ar3 temperature, or Ar3+20°C) is reached during a rolling pass. In other words, the plate thickness TCa (mm) when a specific temperature TPa (℃) is reached during the rolling pass is: TCa=TCO+(TCI-TCO)×(TPa-TPO) / (TPI-TPO) can be obtained by:

[0065] It should be noted that the above assumption also assumes that the exit temperature of the rolling pass will be higher than the entry temperature. In other words, even in a situation where a steel sheet whose entry temperature TPI of the pass is lower than the Ar3 temperature rises in temperature due to processing heat in the pass and is discharged at an exit temperature TPO of Ar3 temperature or higher, it is determined that the steel sheet has been rolled in the γ range (temperature range of Ar3 temperature or higher and Ar3+20°C or lower) required for the present disclosure in the latter half of the pass. It is also possible that the temperature fluctuations on either side of the Ar3 temperature may occur over multiple passes. In such a case, in this embodiment, the rolling conditions in the α region are for the "final rolling process in the α region". In addition, the rolling conditions in the γ region are for the "rolling process in the γ region immediately before the above-mentioned 'final rolling process in the α region'". In other words, when the rolling temperature after starting hot rolling in the γ region changes as follows: γ region (start of hot rolling) ⇒ α region 1 ⇒ γ region 1 ⇒ α region 2 ⇒ γ region 2 ⇒ α region 3 (end of hot rolling), if the α region 3 and γ region 2 meet the conditions of this embodiment, it is possible to obtain the disclosed steel sheet.

[0066] The rolling temperature in each pass can be measured, for example, by a thermometer installed at the entry or exit of the rolling stand that performs the reduction of the target pass. It is not necessary to install thermometers at the entry and exit of all rolling stands whose temperature range falls within the range disclosed herein, and the rolling temperature at intermediate rolling stands may be calculated from the actual temperatures of thermometers appropriately installed before and after them. Rather, in current hot rolling, control using such calculated temperatures is usually performed. The finish rolling temperature FT is preferably set to be lower than the Ar3 temperature.

[0067] Thereafter, the hot rolled steel sheet is coiled without being annealed. The coiling temperature is preferably more than 250°C and not more than 600°C. By coiling the hot rolled steel sheet after hot rolling at more than 250°C and not more than 600°C, the crystal format before cold rolling can be refined, and the effect of imparting {411} crystal orientation with excellent magnetic properties during bulging can be obtained. From this viewpoint, the coiling temperature is more preferably 350°C to 550°C, and further preferably 400°C to 480°C.

[0068] (Cold rolling process) In the cold rolling process, the hot rolled steel sheet after the cooling process is cold rolled to obtain a cold rolled steel sheet. Specifically, after hot rolling, the hot rolled steel sheet is pickled and then cold rolled. In the cold rolling, the reduction is preferably 80% to 92%. The lower limit of the reduction may be 83% or more, and may further be 85% or more. The upper limit of the reduction may be 90% or less. Note that the higher the reduction, the easier it is for crystal grains having the {411} crystal orientation to grow due to subsequent bulging, but the sheet shape deteriorates and operation becomes more difficult.

[0069] (Intermediate annealing process) In the intermediate annealing step, intermediate annealing is performed on the cold rolled steel sheet. In this embodiment, the temperature of intermediate annealing is controlled to be less than 650 to 700 ° C. If the temperature of intermediate annealing is 700 ° C or higher, excessive grain growth of crystal grains will occur, and even if skin pass rolling and final annealing are performed as described below, the accumulation of crystal grains in the {411} crystal orientation will not progress easily, and the development of {110} crystal grains will be promoted. If the temperature of intermediate annealing is less than 650 ° C, sufficient recrystallization will not occur, and the growth of crystal grains having the {411} crystal orientation will be inhibited even if skin pass rolling and final annealing are performed as described below. Therefore, the temperature of intermediate annealing is preferably 650 ° C or higher. The lower limit of the temperature of intermediate annealing may be 660 ° C or higher, and may further be 680 ° C or higher. The temperature described here is based on the premise of continuous annealing, and the time of intermediate annealing is preferably in the range of 5 to 120 seconds. This annealing temperature range and annealing time range are considered to be suitable conditions for allowing the {411} crystal grains, which are formed in no small amount by the cold rolling process, to grow moderately by bulging and for creating a state in which strain-induced grain growth is likely to occur by the skin-pass rolling and final annealing described below.

[0070] (Skin pass rolling process) In the skin pass rolling process, skin pass rolling is performed on the steel sheet after the intermediate annealing process. As described above, when skin pass rolling and annealing are performed in a state where the {411} crystal orientation is enriched by bulging, the crystal grains having the {411} crystal orientation further grow. This is because, due to skin pass rolling, strain hardly accumulates in the crystal grains having the {411} crystal orientation, while strain easily accumulates in the crystal grains belonging to the orientation group having the {111} plane orientation called γ-fiber such as {111}<112> and {111}<110>. In the subsequent annealing, the crystal grains having the {411} crystal orientation with less strain eat away these γ-fiber oriented grains using the strain difference as the driving force. This eating phenomenon occurring with the strain difference as the driving force is called strain-induced grain boundary migration (hereinafter, SIBM). The reduction ratio of the skin pass rolling is preferably 5% to less than 20%. If the reduction ratio is less than 5%, the amount of strain is too small, so strain-induced grain boundary migration (hereinafter, SIBM) does not occur in the subsequent annealing, and the crystal grains having the {411} crystal orientation do not grow. On the other hand, if the reduction ratio is 20% or more, the amount of strain becomes too large, and recrystallization nucleation (hereinafter Nucleation) occurs in which new crystal grains are generated from among the crystal grains having the γ-fiber orientation. In this Nucleation, most of the generated grains have the crystal grains having the γ-fiber orientation, so the magnetic properties deteriorate. From this viewpoint, the reduction ratio of the skin pass rolling is more preferably 8% to 15%. In addition, in the non-oriented electrical steel sheet, when making it have the strain distribution described above, when the reduction ratio (%) of the cold rolling is RR1 and the reduction ratio (%) at the time of skin pass rolling is RR2, it is preferable to adjust the reduction ratios of the cold rolling and the skin pass rolling so as to satisfy 88 < RR1 + 0.2×RR2 < 93 and 5 ≤ RR2 < 20.

[0071] Here, the reduction ratio RR1 (%) in the cold rolling is defined as follows.

[0072] Reduction ratio RR1 (%) = (1 - thickness of the sheet after rolling in the final pass of the cold rolling / thickness of the sheet before rolling in the first pass of the cold rolling) × 100 The reduction ratio RR2 (%) in skin pass rolling is defined as follows. Reduction ratio RR2 (%) = (1 - thickness after the final pass of skin pass rolling / thickness before the first pass of skin pass rolling) x 100

[0073] (Final annealing process) In the final annealing step, the steel sheet after the skin-pass rolling is subjected to final annealing. This final annealing generates SIBM driven by the strain difference for each crystal orientation due to skin-pass rolling, and crystal grains having the {411} crystal orientation targeted by the present disclosure grow preferentially, increasing the {411} crystal orientation density of the steel sheet. This annealing condition can be appropriately set by a person skilled in the art while confirming the occurrence of SIBM, and is not particularly limited, but an example can be annealing at 800°C for 2 hours.

[0074] As described above, the non-oriented electrical steel sheet according to this embodiment can be manufactured. This final annealing is performed after skin pass rolling, for example, when the steel sheet is in the form of a steel sheet coil at a steel sheet manufacturer. It is possible to perform the final annealing in the form of a sheet or as a cut sheet. Alternatively, after skin pass rolling, the steel sheet may be shipped without undergoing final annealing, and the motor manufacturer may process the steel sheet into a predetermined shape as a motor core, laminate the steel sheet, and perform the final annealing in the core shape. In the latter case, the final annealing can be performed at the same time as the "strain relief annealing" that is generally performed for motor cores by the motor manufacturer. If the steel sheet manufacturer performs the final annealing before shipping, motor manufacturers can use the disclosed steel sheet to obtain good motor characteristics. Also, if the steel sheet manufacturer ships the steel sheet up to skin pass rolling, and the motor manufacturer processes it into a motor core and then performs the final annealing as stress relief annealing, good motor characteristics can also be obtained using the disclosed steel sheet.

[0075] The steel member made of the non-oriented electromagnetic steel sheet according to the present embodiment is applied to, for example, the iron core (motor core) of a rotating electric machine. In this case, individual flat thin plates are cut out from the non-oriented electromagnetic steel sheet according to the present embodiment, and these flat thin plates are appropriately laminated to produce an iron core used in a rotating electric machine. Since the non-oriented electromagnetic steel sheet having excellent magnetic properties is applied to this iron core, the iron loss is kept low, and a rotating electric machine having excellent torque is realized. The steel member made of the non-oriented electromagnetic steel sheet according to the present embodiment can also be applied to products other than the iron core of a rotating electric machine, for example, the iron core of a linear motor or a stationary machine (reactor or transformer). EXAMPLES

[0076] Next, the non-oriented electrical steel sheet according to the embodiment of the present disclosure will be specifically described with reference to examples. The examples shown below are merely examples of the non-oriented electrical steel sheet according to the embodiment of the present disclosure, and the non-oriented electrical steel sheet according to the present disclosure is not limited to the examples below.

[0077] The molten steel was cast to produce an ingot having the composition shown in Table 1 below. In Table 1, "Co, etc." indicates the respective contents of Co, Pt, Pb, and Au. The produced ingot was then subjected to a hot rolling process, a cold rolling process, an intermediate rolling process, a skin pass rolling process, and a final annealing process under the conditions shown in Table 2. The final annealing in the final annealing process was performed at the temperature shown in Table 2 for 2 hours. The following characteristics were then examined using the above-mentioned method. Transformation temperature Ar3(℃) Plate thickness Area ratio of {411} grains Sac Area ratio of {110} grains Sag The area ratio Sbc of {411} grains in the region from the high KAM value to 20% Magnetic flux density B in the rolling direction 50L Magnetic flux density B at 45° to the rolling direction 50D Magnetic flux density B at 90° to the rolling direction 50C

[0078] To investigate the texture of the skin-pass rolled material, a part of the steel sheet after skin-pass rolling was cut, the cut test piece was processed to reduce the thickness to 1 / 2, and the processed surface (the polished surface where the steel sheet was polished to 1 / 2 from the sheet surface side) was observed by EBSD (step interval: 0.3 μm) as described above. The areas of the orientation grains of the types shown in Table 3 were obtained from the EBSD observation using OIM Analysis 7.3. Next, 55 mm square specimens were taken from the steel sheets after final annealing as measurement samples. At this time, a specimen with one side parallel to the rolling direction and a specimen with one side inclined at 45 degrees to the rolling direction were taken. The specimens were taken using a shearing machine. And the magnetic flux density B in the rolling direction 50L、 Magnetic flux density B at 45° to the rolling direction 50D、 Magnetic flux density B at 90° to the rolling direction 50C The measurements were made in accordance with JIS C2556 (2015). The measurement results are shown in Table 3.

[0079] The following evaluations were also carried out:

[0080] (Rollability) The rollability was evaluated as follows: In a 1 m long longitudinal region centered on a position 10 m longitudinally from the outermost longitudinal tip of the cold-rolled sheet coil (top part), a position half the length of the entire longitudinal length of the coil from the outermost longitudinal tip of the coil (middle part), and a position 10 m longitudinally from the innermost longitudinal tip of the coil (bottom part), if cracks of 1 cm or more in length were present in a total of two or more places on both end faces in the sheet width direction of the coil, the rating was "N", otherwise "Y". In this embodiment, the cold-rolled coil was used as the evaluation target for rollability, but when evaluating a steel sheet cut out from a cold-rolled coil, both end faces in the sheet width direction may be observed in three or more different positions in the longitudinal direction (rolling direction) of the steel sheet in the same manner as described above. For example, the observation may be performed in a range of about 1 / 10 of the entire longitudinal length of the steel sheet, centered on positions of about 1 / 10, 1 / 2, and 9 / 10 of the longitudinal length of the steel sheet, and the entire longitudinal length of the steel sheet may be 1 m or more.

[0081] [Table 1-1]

[0082] [Table 1-2]

[0083] [Table 2-1]

[0084] [Table 2-2]

[0085] [Table 3-1]

[0086] [Table 3-2]

[0087] As can be seen from the above examples, the non-oriented electrical steel sheet according to the present disclosure has excellent magnetic properties in the direction at 45° from the rolling direction by appropriately controlling the chemical composition, hot rolling conditions, cold rolling conditions, intermediate annealing conditions, skin pass rolling conditions, and final annealing process conditions. In addition, there is no problem with rollability. [Industrial Applicability]

[0088] According to the present disclosure, it is possible to provide a non-oriented electrical steel sheet which has no problems with rollability and can obtain excellent magnetic properties in a direction at an angle of 45° from the rolling direction, and therefore is extremely useful industrially.

[0089] The disclosure of Japanese Patent Application No. 2023-001936 is incorporated herein by reference in its entirety. All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims

1. In mass percent, C: 0.0100% or less, Si: 1.50% to 4.00%, sol. Al: 0.0001% to 1.0%, S: 0.0100% or less, N: 0.0100% or less, Mn: 0.10% or more, One or more selected from Mn, Ni, and Cu: less than 2.50% in total; Mo: 0.00% to less than 2.50% Cr: 0.00% to less than 2.50%; Ti: 0.000% to 0.005%, Nb: 0.000% to 0.005%, Sn: 0.000% to 0.400%, Sb: 0.000% to 0.400%, P: 0.000% to 0.400%, and One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.0000% to 0.0100% in total; When the C content is [C], the Mo content is [Mo], the Cr content is [Cr], the Mn content is [Mn], the Ni content is [Ni], the Cu content is [Cu], the Si content is [Si], the sol. Al content is [sol. Al], and the P content is [P], the transformation temperature Ar is determined by the following formula (1). ３ (°C) is 750 to 1050°C, with the balance being Fe and impurities; And the plate thickness is 0.50 mm or less, In the cross section at the half thickness position, the area ratio of {411} crystal grains is Sac, the area ratio of {110} crystal grains is Sag, and the area ratio of {411} crystal grains in the region up to 20% from the high KAM (Kernel Average Misorientation) value is Sbc. Sac>0.120, Sac>Sbc>Sag, and 0.050>Sag are satisfied. The KAM value of this non-oriented electrical steel sheet is set so that the limit for inclusion in the KAM value is an orientation difference of 5° or less with adjacent pixels, and the KAM value is the average value of the orientation difference calculated between the most adjacent measurement points. Ar ３ (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.-]-120×([M]+[[[[[[])-46×([[[[[Ni]) ・・・(1)

2. In mass percent, C: 0.0100% or less, Si: 1.50% to 4.00%, sol. Al: 0.0001% to 1.0%, S: 0.0100% or less, N: 0.0100% or less, Mn: 0.10% or more, One or more selected from Mn, Ni, Co, Pt, Pb, Au, and Cu: less than 2.50% in total; Mo: 0.00% to less than 2.50% Cr: 0.00% to less than 2.50%; Ti: 0.000% to 0.005%, Nb: 0.000% to 0.005%, Sn: 0.000% to 0.400%, Sb: 0.000% to 0.400%, P: 0.000% to 0.400%, and One or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.0000% to 0.0100% in total; When the C content is [C], the Mo content is [Mo], the Cr content is [Cr], the Mn content is [Mn], the Ni content is [Ni], the Cu content is [Cu], the Si content is [Si], the sol. Al content is [sol. Al], and the P content is [P], the transformation temperature Ar is determined by the following formula (1). ３ (°C) is 750 to 1050°C, with the balance being Fe and impurities; And the plate thickness is 0.50 mm or less, In the cross section at the half thickness position, the area ratio of {411} crystal grains is Sac, the area ratio of {110} crystal grains is Sag, and the area ratio of {411} crystal grains in the region up to 20% from the high KAM (Kernel Average Misorientation) value is Sbc. Sac>0.120, Sac>Sbc>Sag, and 0.050>Sag are satisfied. The KAM value of this non-oriented electrical steel sheet is set so that the limit for inclusion in the KAM value is an orientation difference of 5° or less with adjacent pixels, and the KAM value is the average value of the orientation difference calculated between the most adjacent measurement points. Ar ３ (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.-]-120×([M]+[[[[[[])-46×([[[[[Ni]) ・・・(1)

3. Magnetic flux density B in the rolling direction after heat treatment at 750 to 850 ° C for 2 hours ５０ is 1.58T or more, and the magnetic flux density B ５０ The non-oriented electrical steel sheet according to claim 1 or 2, wherein the Tc is 1.70T or more.

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