Non-oriented electrical steel sheet

Abstract

Provided is a non-oriented electromagnetic steel sheet which has a prescribed chemical composition and which, when observed by EBSD in a plane parallel to the steel sheet surface, satisfies expressions (3)-(7), where Stot is the total area, S411 is the area of {411} oriented grains, S100 is the area of {100} oriented grains, Styl is the area of oriented grains having a Taylor factor M of more than 2.9 according to expression (2), Stra is the sum total area of oriented grains having a Taylor factor M of not more than 2.9, K411 is the average KAM value of {411} oriented grains, and Ktyl is the average KAM value of oriented grains having a Taylor factor M of more than 2.9.　(2): M=(cosφ×cosλ)-1 (3): S411 / S100>1.00 (4): 0.20≤Styl / Stot≤0.85 (5): 0.05≤S411 / Stot≤0.80 (6): S411 / Stra≥0.50 (7): K411 / Ktyl≤0.990

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 a direction parallel to the sheet surface.

[0003] For this purpose, the easy axis of magnetization of the crystal ( <100> It is advantageous to control the texture of the steel sheet so that the {100} orientation, {110} orientation, {111} orientation, etc., coincide with the in-plane direction of the sheet. Regarding such texture control, many techniques have been disclosed for controlling the {100} orientation, {110} orientation, {111} orientation, etc., such as those described in Patent Documents 1 to 5.

[0004] Various methods have been devised for controlling the texture, including a technology that utilizes "strain-induced grain growth." Under specific conditions, strain-induced grain growth can suppress the accumulation of the {111} orientation, which does not have an easy axis of magnetization in the in-plane direction of the sheet, and is therefore effectively used in non-oriented electrical steel sheets. These technologies are disclosed in Patent Documents 6 to 10, etc.

[0005] However, while the conventional method can suppress the accumulation of the {111} orientation, the accumulation of the {110} <001> The Goss orientation (hereafter, Goss orientation) grows. The Goss orientation has better magnetic properties in one direction than the {111} orientation, but the magnetic properties are hardly improved on the average all around. Therefore, the conventional method has the problem that it is not possible to obtain excellent magnetic properties on the average all around.

[0006] In addition, in order to realize excellent magnetic properties on an average all around, technologies for developing {100} crystal orientation or {411} crystallography in a composition system in which γ→α phase transformation occurs are disclosed in Patent Documents 11 to 13. In these technologies, a fine-grained α phase structure is realized at the time of hot rolling by using a steel composition with a low γ→α phase transformation temperature and transforming at a low temperature, and 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 accumulation of strain. However, Mn is known as a segregation element, and if the amount added is increased, it segregates in the center of the thickness of the hot rolled sheet, causing cracks when the hot rolled sheet is cold rolled. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2017-193754 [Patent Document 2] Japanese Patent Application Publication No. 2011-111658 [Patent Document 3] International Publication No. 2016 / 148010 [Patent Document 4] Japanese Patent Application Publication No. 2018-3049 [Patent Document 5] International Publication No. 2015 / 199211 [Patent Document 6] Japanese Patent Publication No. 8-143960 [Patent Document 7] Japanese Patent Application Publication No. 2002-363713 [Patent Document 8] Japanese Patent Publication No. 2011-162821 [Patent Document 9] Japanese Patent Publication No. 2013-112853 [Patent Document 10] Japanese Patent No. 4029430 [Patent Document 11] International Publication No. 2021 / 095846 [Patent Document 12] International Publication No. 2021 / 095851 [Patent Document 13] International Publication No. 2021 / 095880 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above-mentioned problems, the present disclosure aims to provide a non-oriented electrical steel sheet having a chemical composition in which Mn is suppressed and the contents of elements such as Cu and Ni are optimized so that rollability is not an issue, and which has small in-plane anisotropy and excellent magnetic properties averaged all around (averaged in all directions). [Means for solving the problem]

[0009] The present inventors have investigated a technique for forming a favorable texture for non-oriented electrical steel sheets by utilizing strain-induced grain growth. <uvw>The grains with {411} orientation are also {100} <uvw>We focused on the fact that {411} orientation is a crystal grain that is as resistant to distortion as {100} orientation (hereafter referred to as {100} orientation). In other words, by increasing the number of {411} orientation grains compared to {100} orientation grains at the stage before strain-induced grain growth occurs, the {411} orientation grains mainly encroach on the {111} orientation grains due to strain-induced grain growth, while at the same time suppressing the development of {100} orientation grains, and a non-oriented electrical steel sheet with {411} orientation as the main orientation is manufactured. In this way, it was found that by sufficiently suppressing the development of {100} orientation grains and making {411} orientation the main orientation, the magnetic properties of the entire circumference average (average of the rolling direction, width direction, 45 degree direction to the rolling direction, and 135 degree direction to the rolling direction) are improved.

[0010] The inventors also investigated a method for increasing the number of crystal grains with the {411} orientation compared to the number of crystal grains with the {100} orientation at a stage before strain-induced grain growth occurs, and discovered a method in which hot rolling is performed under specific conditions for a steel type with a low content of Mn, Ni, Cu, etc., and then cold rolling and annealing are performed, followed by re-cold rolling (skin pass rolling) at a lower reduction ratio, followed by final annealing.

[0011] The present inventors have conducted further intensive research based on these findings and have arrived at the following aspects of the disclosure.

[0012] (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: 0.0% to less than 2.5% Cr: 0.0% to less than 2.5% 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%, C content is [C], Mo content is [Mo], Cr content is [Cr], Mn content is [Mn], Ni content is [Ni], Cu content is [Cu], and Si content is [Si] The transformation temperature Ar is defined by the following formula (1), where the sol.Al content is [sol.Al] and the P content is [P]. 3 (°C) is 750 to 1050°C, with the balance being Fe and impurities; Furthermore, when observing the surface of the steel sheet by EBSD, the total area was S tot , the area of ​​the {411} oriented grains is S 411 , the area of ​​the {100} oriented grains is S 100 The area of ​​oriented grains with a Taylor factor M of more than 2.9 according to the following formula (2) is defined as S tyl The total area of ​​oriented grains with the Taylor factor M of 2.9 or less is defined as S tra , the average KAM value of {411} oriented grains is K 411 The average KAM value of the oriented grains having the Taylor factor M of more than 2.9 is K tyl In this case, the following ( Formula 3) and formulas (4) to (7) are satisfied. Ar 3 (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1) M = (cosφ × cosλ) -1 (2) S 411 / S 100 >1.00 (3) 0.20≦S tyl / S tot ≦0.85 (4) 0.05≦S 411 / S tot ≦0.80 (5) S 411 / S tra ≧0.50 (6) K 411 / K tyl ≦0.990 (7) Here, φ in equation (2) represents the angle between the stress vector and the crystal slip direction vector, and λ represents the angle between the stress vector and the normal vector of the crystal slip plane. (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: 0.0% to less than 2.5% Cr: 0.0% to less than 2.5% 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, and a transformation temperature Ar defined by the following formula (1) 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], 3 (°C) is 750 to 1050°C, with the balance being Fe and impurities; Furthermore, when observing the surface of the steel sheet by EBSD, the total area was S tot , the area of ​​the {411} oriented grains is S 411 , the area of ​​the {100} oriented grains is S 100 The area of ​​oriented grains with a Taylor factor M of more than 2.9 according to the following formula (2) is defined as S tyl The total area of ​​oriented grains with the Taylor factor M of 2.9 or less is defined as S tra , the average KAM value of {411} oriented grains is K 411 The average KAM value of the oriented grains having the Taylor factor M of more than 2.9 is K tyl In this case, the following formula (3) and formulas (4) to (7) are satisfied. Ar 3 (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1) M = (cosφ × cosλ) -1 (2) S 411 / S 100 >1.00 (3) 0.20≦S tyl / S tot ≦0.85 (4) 0.05≦S 411 / S tot ≦0.80 (5) S 411 / S tra ≧0.50 (6) K 411 / K tyl ≦0.990 (7) Here, φ in equation (2) represents the angle between the stress vector and the crystal slip direction vector, and λ represents the angle between the stress vector and the normal vector of the crystal slip plane. (3) 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: 0.0% to less than 2.5% Cr: 0.0% to less than 2.5% 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 transformation temperature Ar is defined by the following formula (1) when the C content is [C], Mo content is [Mo], Cr content is [Cr], Mn content is [Mn], Ni content is [Ni], Cu content is [Cu], Si content is [Si], sol.Al content is [sol.Al], and P content is [P] in mass%. 3 (°C) is 750 to 1050°C, with the balance being Fe and impurities; Furthermore, when observing the surface of the steel sheet by EBSD, the total area was S tot , the area of ​​the {411} oriented grains is S 411 , the area of ​​the {100} oriented grains is S 100 The area of ​​oriented grains with a Taylor factor M of more than 2.9 according to the following formula (2) is defined as S tyl The total area of ​​oriented grains with the Taylor factor M of 2.9 or less is defined as S tra In this case, the following expressions (8) to (11) are satisfied. Ar 3 (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1) M = (cosφ × cosλ) -1 (2) S 411 / S 100 >2.00 ···(8) S tyl / S tot <0.55 ···(9) S 411 / S tot >0.30 (10) S 411 / S tra ≧0.60 (11) Here, φ in equation (2) represents the angle between the stress vector and the crystal slip direction vector, and λ represents the angle between the stress vector and the normal vector of the crystal slip plane. (4) 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: 0.0% to less than 2.5% Cr: 0.0% to less than 2.5% 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 transformation temperature Ar is defined by the following formula (1) when the C content is [C], Mo content is [Mo], Cr content is [Cr], Mn content is [Mn], Ni content is [Ni], Cu content is [Cu], Si content is [Si], sol.Al content is [sol.Al], and P content is [P] in mass%. 3 (°C) is 750 to 1050°C, with the balance being Fe and impurities; Furthermore, when observing the surface of the steel sheet by EBSD, the total area was S tot , the area of ​​the {411} oriented grains is S 411 , the area of ​​the {100} oriented grains is S 100 The area of ​​oriented grains with a Taylor factor M of more than 2.9 according to the following formula (2) is defined as S tyl The total area of ​​oriented grains with the Taylor factor M of 2.9 or less is defined as S tra In this case, the following expressions (8) to (11) are satisfied. Ar 3 (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1) M = (cosφ × cosλ) -1 (2) S 411 / S 100 >2.00 ···(8) S tyl / S tot <0.55 ···(9) S 411 / S tot >0.30 (10) S 411 / S tra ≧0.60 (11) Here, φ in equation (2) represents the angle between the stress vector and the crystal slip direction vector, and λ represents the angle between the stress vector and the normal vector of the crystal slip plane. Effect of the Invention

[0013] 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 the addition of Mn is suppressed and the contents of elements such as Cu and Ni are optimized so that rollability does not become an issue, and the steel sheet has small in-plane anisotropy and excellent circumferential average (all-directional average) magnetic properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The non-oriented electrical steel sheet according to this embodiment is manufactured by subjecting a steel material having a chemical composition described below to a hot rolling process, a cold rolling process, an intermediate annealing process, and a skin pass rolling process. Furthermore, a non-oriented electrical steel sheet according to another embodiment of the present disclosure is manufactured by subjecting a steel material having a chemical composition described below to a cold rolling process, an intermediate annealing process, a skin pass rolling process, and a final annealing process. In the non-oriented electrical steel sheet according to the present embodiment, the amount of Mn added is kept low to ensure rollability, and further, the components are adjusted, and then the hot rolling conditions are optimized to form an appropriate α-deformed grain structure at the hot-rolled sheet stage, which allows the {411} oriented grains to develop during the subsequent cold rolling and intermediate annealing. By making the number of {411} oriented grains greater than the {100} oriented grains at a stage before strain-induced grain growth occurs, the {411} oriented grains mainly encroach on the {111} oriented grains due to strain-induced grain growth, while at the same time suppressing the development of the {100} oriented grains, thereby producing a non-oriented electrical steel sheet with the {411} oriented grains as the main orientation. The final annealing after skin pass rolling causes strain induced grain growth and / or normal grain growth in the steel sheet. Furthermore, fully suppressing the development of the {100} orientation while enriching the {411} oriented grains is effective in reducing the in-plane anisotropy of the magnetic properties and improving the circumferential average (all-directional average).

[0015] In addition, the steel sheet after skin-pass rolling is in a relationship with the base sheet of the steel sheet after strain-induced grain growth and normal grain growth. Hereinafter, the steel sheet after skin-pass rolling and the steel sheet after strain-induced grain growth and normal grain growth, regardless of whether they are before or after final annealing, will be described as a non-oriented electrical steel sheet.

[0016] In addition, in the non-oriented electrical steel sheet according to this embodiment, by increasing the number of crystal grains centered on the {411} orientation (hereinafter, {411} orientation grains) compared to the {100} orientation grains in the metal structure of the steel sheet before skin-pass rolling, the number of {411} orientation grains is further increased in the subsequent skin-pass rolling and final annealing, improving the magnetic properties all around. The number of {411} orientation grains may be increased before skin-pass rolling in a process other than that described above.

[0017] First, the chemical composition of the grain-oriented electrical steel sheet, which is the raw material used in the non-oriented electrical steel sheet and its manufacturing method according to this embodiment, will be described. Since the chemical composition does not change by rolling or heat treatment, the chemical composition of the grain-oriented electrical steel sheet, which is the raw material, is the same as the chemical composition of the non-oriented steel sheet obtained through each process. In the following description, "%", which is the unit of the content of each element contained in the non-oriented electrical steel sheet or steel material, means "mass %" unless otherwise specified.

[0018] 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.

[0019] 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 a certain numerical range may be replaced by the upper limit value of another numerical range described in stages, 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.

[0020] 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.

[0021] 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%.

[0022] Examples of impurities include those contained in raw materials such as ores and scraps, and those contained in the manufacturing process.

[0023] (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.

[0024] (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. 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.

[0025] (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. In addition, sol.Al means Al 2 O 3 This refers to acid-soluble Al that is not in the form of an oxide such as aluminum oxide, and is soluble in acid.

[0026] Here, the magnetic flux density B 50 is the magnetic flux density in a magnetic field of 5000 A / m.

[0027] (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.

[0028] (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.

[0029] (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.

[0030] (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, Ar, which is one of the features of this embodiment, 3 Even when considering the control of the transformation point, the inclusion of Mn, Ni, and Cu results in the 3 It is preferable to control the transformation point. For this reason, the total amount of Co, Pt, Pb, and Au is less than 0.5%, more preferably 0.1% or less, and furthermore, the amount is limited to the range of unavoidable elements, and there is no need to actively add them (it may be 0%).

[0031] Furthermore, the non-oriented electrical steel sheet and steel material according to the present embodiment further satisfy the following condition as a condition for 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], the transformation temperature Ar defined by the following formula (1) is 3 (℃) must be within the range of 750 to 1050℃.

[0032] Ar 3 (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni]) ···(1)

[0033] 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, and therefore sufficient magnetic flux density cannot be obtained even if the manufacturing method described below is applied. 3 If the transformation point is less than 750°C, the hot rolling temperature will be low, resulting in high deformation resistance and excessive load on the rolling mill, and the amount of added elements will be high, leading to a decrease in the toughness of the hot-rolled sheet and cold-rolled sheet. Therefore, this value is set as the lower limit. 3 If the transformation point exceeds 1050°C, the hot rolling temperature becomes too high, requiring extremely high temperature heating, which increases the load on the heating furnace, or the composition does not allow γ→α transformation to occur, so this value is set as the upper limit.

[0034] (Mn: 0.10% or more) Mn is Ar 3 The transformation point is lowered, and in the component system of the non-oriented electrical steel sheet according to this embodiment, the grains of the hot-rolled sheet can be refined by phase transformation. Mn is an element that increases the electrical resistance of steel and reduces iron loss. Therefore, Mn is contained at 0.1% or more. From this viewpoint, Mn is preferably contained at 0.5% or more. More preferably, it is contained at 1.0% 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 upper limit of the Mn content is less than 2.5%. The upper limit of the Mn content is preferably 2.3 mass% or less, and more preferably 2.0 mass%.

[0035] (Cu: Less than 2.5% in total with the above elements) Like Mn, Cu is an element that increases the electrical resistance of steel sheets and reduces iron loss. 3 Cu is an element that lowers the 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 during annealing after cold rolling due to an increase in the 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 caution is required. 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. The upper limit of the Cu content is not limited, but is less than 2.5%. In addition, the upper limit of the Cu content is preferably 1.5 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.

[0036] (Ni: Less than 2.5% in total with the above elements) 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 reduce 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. The upper limit of the Ni content is not limited, but is 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, but may be, for example, 0.01% or more.

[0037] (Mo: 0.0% to less than 2.5%) Mo is Ar 3 Mo is an element that lowers the 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 added as necessary, and it is preferable to add 0.1% or more. On the other hand, since adding 2.5% or more of Mo significantly reduces the cold workability, the Mo content is set to less than 2.5%.

[0038] (Cr: 0.0% to less than 2.5%) Cr is Ar 3 Cr is an element that lowers the 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, and has the effect of improving not only strength adjustment and corrosion resistance, but also particularly high-frequency characteristics. 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%.

[0039] (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.

[0040] (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.

[0041] (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.

[0042] 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.

[0043] (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 content of these elements exceeds 0.0100%, the total amount of sulfides or oxysulfides or both will be excessive, which will inhibit recrystallization and grain growth during annealing such as intermediate annealing. Therefore, the total content of the elements that form coarse precipitates is set to 0.0100% or less.

[0044] 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.

[0045] 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.

[0046] Next, the thickness of the non-oriented electrical steel sheet according to the present embodiment will be described. The thickness of the non-oriented electrical steel sheet is not particularly limited. The preferred thickness of the non-oriented electrical steel sheet according to the present embodiment is 0.10 to 0.50 mm. Usually, as the sheet thickness becomes thinner, the iron loss becomes lower, but the magnetic flux density becomes lower. In view of this, if the sheet thickness is 0.10 mm or more, the iron loss becomes lower and the magnetic flux density becomes higher. Also, if the sheet thickness is 0.50 mm or less, low iron loss can be maintained.

[0047] Next, the metal structure of the non-oriented electrical steel sheet according to the present embodiment will be described. Hereinafter, the non-oriented electrical steel sheet according to each embodiment will be specified based on the metal structure after skin pass rolling and the metal structure after final annealing.

[0048] First, the metal structure to be identified and the method for identifying it will be described. The metal structure to be identified in this embodiment is identified in a cross section parallel to the sheet surface of the steel sheet, and is identified by the following procedure.

[0049] First, the sample is polished to 7 / 8 of the thickness so that the 1 / 8 thickness position is exposed, and the polished surface (polished surface polished to 1 / 8 from the sheet side of the steel sheet) 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 for samples after skin pass rolling and 2000 μm x 2000 μm for samples after stress relief annealing. Observation may be performed at several locations divided into several small sections. The step interval during measurement is 0.3 μm for samples after skin pass rolling and 2.0 μm for samples after stress relief annealing. The following types of areas and KAM (Kernel Average Misorientation) values ​​are obtained from the EBSD observation data using a general method. 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.

[0050] S tot : Total area (observation area) S tyl : The total area of ​​oriented grains with a Taylor factor M of more than 2.9 according to the following formula (2) S tra : The total area of ​​oriented grains with a Taylor factor M of 2.9 or less according to the following formula (2) S 411 : Total area of ​​{411} oriented grains S 100 : Total area of ​​{100} oriented grains K tyl : The average KAM value of oriented grains whose Taylor factor M according to the following formula (2) exceeds 2.9 K 411 : Average KAM value of {411} oriented grains Here, the orientation tolerance of the crystal plane orientation is set to 10°. In addition, hereinafter, when describing a specific crystal plane orientation, the orientation tolerance is also set to 10°. In other words, crystal grains having a plane orientation within ±10° of a specific plane orientation described in this disclosure are treated as crystal grains having that specific crystal orientation.

[0051] Here, the Taylor factor M is assumed to comply with the following equation (2). M = (cosφ × cosλ) -1 (2) φ: Angle between the stress vector and the crystal slip vector λ: Angle between the stress vector and the normal vector of the crystal slip plane

[0052] The Taylor factor M is determined by the slip deformation of the crystal along the slip plane {110} or {112}, and the slip direction <111> This is the Taylor factor when it is assumed that deformation occurs in the plate width direction, but compression deformation in the plate thickness direction and elongation deformation in the rolling direction occur without deformation in the plate width direction.

[0053] Here, we will explain how to obtain the Taylor factor by analyzing SEM-EBSD data with OIM Analysis 7.3. In the chart creation function of OIM Analysis 7.3, select Taylor Factor as the type. The detailed conditions for obtaining the Taylor factor are as follows. Select Iron (Alpha) as the Phase of the slip system, and enter the following two items as the slip system. Sliding surface: 101, sliding direction: 11-1, CRSS: 0.2 Sliding surface: 112, sliding direction: 11-1, CRSS: 0.2 In addition, if you select a combination of slip planes and slip directions that results in a dot product of 0, the same results will be obtained even if the order or signs of the numbers are different. Enter the same value for CRSS (Critical Resolved Shear Stress) for the two slip systems. The following rolling deformation tensor is input as Deformation Gradient. RD, TD, ND RD 1 0 0 T.D. 0 0 0 ND 0 0 -1 The Taylor factors of all measurement points under these conditions are calculated as a histogram, and the results can be converted into the area ratios of oriented grains with Taylor factors of 2.9 or more and less than 2.9.

[0054] Next, in the following first and second embodiments, the features are defined by the above-mentioned area and KAM value.

[0055] (Embodiment 1) First, the metal structure of the non-oriented electrical steel sheet after skin-pass rolling will be explained. This metal structure has accumulated strain sufficient to cause strain-induced grain growth, and can be considered as the initial stage before strain-induced grain growth occurs. The characteristics of the metal structure of the steel sheet after skin-pass rolling are roughly determined by the orientation for the development of crystal grains in the desired orientation and the conditions related to the strain sufficiently accumulated to cause strain-induced grain growth.

[0056] In the non-oriented electrical steel sheet according to the first embodiment, the area of ​​each oriented grain satisfies the following formula (3) and formulas (4) to (6). S 411 / S 100 >1.00 (3) 0.20≦S tyl / S tot ≦0.85 (4) 0.05≦S 411 / S tot ≦0.80 (5) S 411 / S tra ≧0.50 (6)

[0057] Although the description has been centered on the {411} orientation grains as the orientation grains that should be preferentially grown, there are many other orientation grains that have a relatively small Taylor factor like the {411} orientation grains and are unlikely to accumulate strain due to processing, and can grow preferentially in strain-induced grain growth. Among them, the {100} orientation is one orientation that is likely to exist in non-oriented electrical steel sheets. This orientation grain competes with the {411} orientation grains that should be preferentially grown. On the other hand, it is difficult to randomly control the orientation of this orientation grain in the steel sheet plane, and if the {100} orientation develops in strain-induced grain growth, the in-plane anisotropy of the properties of the steel sheet will increase, which is inconvenient. For this reason, in the first embodiment, the abundance ratio of {411} orientation grains is specified to be secured among orientations that have a relatively small Taylor factor and are unlikely to accumulate strain due to processing. Area ratio S 411 / S 100 is more than 1.00. In other words, there are more {411} oriented grains than {100} oriented grains. If the development of {100} oriented grains is sufficiently suppressed and the {411} oriented grains are made the main orientation, the magnetic properties on the circumferential average (average of the rolling direction, width direction, direction at 45 degrees to the rolling direction, and direction at 135 degrees to the rolling direction) are improved. Preferably, the area ratio S 411 / S 100 is 2.0 or more, and more preferably the area ratio S 411 / S 100 is 3.0 or higher.

[0058] Area ratio S 411 / S 100 The upper limit of does not need to be particularly limited. For the purposes of this disclosure, The presence of {100} oriented grains is zero and the area ratio S 411 / S 100 There is no problem even if the value of S becomes infinite. However, making the number of {100} oriented grains zero would cause a huge burden in manufacturing, so the area ratio S 411 / S 100 is 20 or less, and more preferably the area ratio S 411 / S 100 is less than or equal to 10.

[0059] Also, S tyl is the abundance of orientations with relatively large Taylor factors. In the strain-induced grain growth process, orientations with small Taylor factors and little accumulation of strain due to processing grow preferentially while eroding orientations with large Taylor factors and accumulated strain due to processing. For this reason, in order to develop special orientations by strain-induced grain growth, S tyl There must be a certain amount of In form 1, the area ratio S tyl / S tot The area ratio S tyl / S tot The area ratio S is 0.20 or more. tyl / S tot If the area ratio S is less than 0.20, the desired crystal orientation will not be sufficiently developed due to strain-induced grain growth. tyl / S tot is 0.30 or more, more preferably 0.50 or more.

[0060] Area ratio S tyl / S tot The upper limit of is related to the amount of grains with the crystal orientation that should be developed in the strain-induced grain growth process described below, but the condition is not simply determined by the ratio of the orientations that grow preferentially and the orientations that are encroached upon. First, as described later, the area ratio S of {411}-oriented grains that should be developed in strain-induced grain growth is 411 / S tot Since is 0.05 or more, the area ratio S tyl / S tot However, the area ratio S tyl / S tot When the amount of is excessive, the preferential growth of the {411} oriented grains does not occur due to the relationship with the amount of strain described later. tyl / S tot is 0.85 or less. It is preferable that the area ratio S tyl / S tot is 0.75 or less, more preferably 0.70 or less.

[0061] In the strain-induced grain growth process described below, {411} oriented grains are preferentially grown. The {411} orientation is one of the orientations in which the Taylor factor is relatively small and strain due to processing is unlikely to accumulate, and is an orientation that can grow preferentially in the strain-induced grain growth process. In the first embodiment, the presence of {411} oriented grains is essential, and in the first embodiment, the area ratio S of {411} oriented grains is 411 / S tot The area ratio of {411} oriented grains S 411 / S tot If the area ratio S is less than 0.05, the {411} oriented grains will not develop sufficiently due to the subsequent strain-induced grain growth. 411 / S tot is 0.10 or more, more preferably 0.20 or more.

[0062] Area ratio S 411 / S tot The upper limit of is determined according to the amount of crystal orientation grains that should be eaten by strain-induced grain growth. In the first embodiment, the area ratio S of the orientations that have a Taylor factor of more than 2.9 that should be eaten by strain-induced grain growth is tyl / S tot Since the area ratio S is 0.20 or more, 411 / S tot The area ratio S is preferably 0.80 or less. However, if the amount of {411} oriented grains before strain-induced grain growth is low, the dominance of grain growth becomes more pronounced, and it becomes possible to develop more {411} oriented grains. Considering this, it is preferable to set the area ratio S 411 / S tot is 0.60 or less, more preferably 0.50 or less, and further preferably 0.40 or less.

[0063] The explanation has been centered on the {411} oriented grains as the grain orientation that should be preferentially grown, but there are many other grain orientations that, like the {411} oriented grains, have a relatively small Taylor factor and are less likely to accumulate strain due to processing, and can grow preferentially in strain-induced grain growth. These grain orientations compete with the {411} oriented grains that should be preferentially grown. On the other hand, these grain orientations are oriented in the direction of the easy axis of magnetization ( <100> Since the number of grains with {411} orientation (orientation) is not as large as that of grains with {411} orientation, and it is difficult to randomize the orientation selection within the steel sheet plane, if these orientations develop due to strain-induced grain growth, the magnetic properties will deteriorate and the in-plane anisotropy of the steel sheet will increase, which is undesirable. For this reason, in embodiment 1, the Taylor factor is specified to ensure the abundance ratio of {411} orientation grains among orientations with a sufficiently small Taylor factor and in which strain due to processing is unlikely to accumulate.

[0064] The area of ​​grains with Taylor factors of 2.9 or less, including grains that are thought to compete with the {411} grains in strain-induced grain growth, is defined as S tra Then, as shown in equation (6), the area ratio S 411 / S tra is set to 0.50 or more to ensure the dominance of the growth of {411} oriented grains. 411 / S tra If the area ratio S is less than 0.50, the {411} oriented grains do not develop sufficiently due to strain-induced grain growth. 411 / S tra is 0.80 or more, more preferably 0.90 or more. 411 / S tra There is no need to specify an upper limit for the Taylor factor of 2.9 or less. All grains with the {411} orientation (S 411 / S tra =1.00).

[0065] In the first embodiment, by combining the above-mentioned crystal orientation with the distortion described below, the {411} oriented grains can be reliably grown and better magnetic properties can be obtained. In the first embodiment, the following formula (7) must be satisfied as a rule regarding the distortion. K 411 / K tyl ≦0.990 (7)

[0066] The requirement for strain is stipulated by equation (7), which is the ratio of the strain (average KAM value) accumulated in {411} oriented grains to the strain (average KAM value) accumulated in oriented grains with a Taylor factor of more than 2.9. Here, the KAM value is the orientation difference between adjacent measurement points within the same grain, and the KAM value is high at locations with a large amount of strain. From a crystallographic point of view, for example, when compressive deformation is performed in the thickness direction in a state of plane strain in a plane parallel to the thickness direction and rolling direction, that is, when a steel sheet is simply rolled, this K 411 and K. tyl Compared to K 411 / K tyl is smaller than 1. However, in reality, due to the influence of constraints from neighboring crystal grains, precipitates present within the crystal grains, and even macroscopic deformation fluctuations including contact with tools (rolling rolls, etc.) during deformation, the strain observed microscopically according to the crystal orientation takes on a variety of forms. For this reason, the purely geometrical orientation effect due to the Taylor factor is difficult to detect. Furthermore, even for grains with the same orientation, very large variations can occur depending on the grain size, grain shape, the orientation and grain size of neighboring grains, the state of precipitates, and the position in the plate thickness direction. Furthermore, even within a single crystal grain, the strain distribution can vary greatly due to the formation of deformation bands near and within the grains, etc.

[0067] Considering such fluctuations, in order to obtain excellent magnetic properties in the first embodiment, K 411 / K tyl is 0.990 or less. 411 / K tyl If K exceeds 0.990, the specificity of the region to be encroached is lost, so that strain-induced grain growth is difficult to occur. 411 / K tyl is 0.970 or less, more preferably 0.950 or less.

[0068] In the metal structure of the non-oriented electrical steel sheet after skin pass rolling in the first embodiment, the grain size is not particularly limited. This is because the relationship with the grain size is not so strong in the state where appropriate strain-induced grain growth occurs by the subsequent final annealing. In other words, whether the desired appropriate strain-induced grain growth occurs can be determined almost entirely by the relationship between the abundance (area) of each crystal orientation and the relationship between the amount of strain for each orientation, in addition to the chemical composition of the steel sheet.

[0069] However, if the crystal grain size becomes too coarse, sufficient grain growth is difficult to occur in a practical temperature range, even though it is induced by strain. In addition, if the crystal grain size becomes too coarse, it becomes difficult to avoid deterioration of magnetic properties. For this reason, it is preferable that the practical average crystal grain size is 300 μm or less. More preferably, it is 100 μm or less, even more preferably, it is 50 μm or less, and particularly preferably, it is 30 μm or less. The finer the crystal grain size, the easier it is to recognize the development of the desired crystal orientation due to strain-induced grain growth when the crystal orientation and strain distribution are appropriately controlled. However, if it becomes too fine, it becomes difficult to form a difference in the amount of strain for each crystal orientation due to the constraint with adjacent grains in the processing to impart strain as described above. From this viewpoint, the average crystal grain size is preferably 3 μm or more, more preferably, 8 μm or more, and even more preferably, 15 μm or more.

[0070] (Embodiment 2) In the above-mentioned embodiment 1, the characteristics of the steel sheet are specified by specifying the strain of the steel sheet by the KAM value. In contrast, in embodiment 2, the steel sheet described in embodiment 1 is annealed for a sufficiently long time and further subjected to grain growth is specified. In such a steel sheet, strain-induced grain growth is almost completed, and as a result, the strain is almost completely released, so that the characteristics are very favorable. In other words, a steel sheet in which {411} orientation grains are grown by strain-induced grain growth, and then normal grain growth is performed by final annealing until the strain is almost completely released becomes a steel sheet with stronger accumulation in the {411} orientation. In embodiment 2, the crystal orientation and crystal grain size of a steel sheet obtained by performing a heat treatment using the steel sheet described in embodiment 1 as a material (i.e., a non-oriented electrical steel sheet obtained by performing final annealing on a non-oriented electrical steel sheet after skin-pass rolling) will be described.

[0071] The crystal orientation of the steel sheet obtained by the final annealing satisfies the following formulas (8) to (11). Equation (8) has a different numerical range compared to equation (3) for non-oriented electrical steel sheet after skin-pass rolling. Strain-induced grain growth during final annealing causes the {411} oriented grains to grow further and increase their area, improving the magnetic properties on an all-around average (average of the rolling direction, width direction, 45° direction to the rolling direction, and 135° direction to the rolling direction). The numerical ranges of the formulas (9) to (11) are different from those of the formulas (4) to (6) for the non-oriented electrical steel sheet after skin pass rolling. This is because, with increasing length, the {411} oriented grains grow further and their area increases, while the grains with Taylor factors of more than 2.9 are mainly encroached upon by the {411} oriented grains and their area decreases further. S 411 / S 100 >2.00 ···(8) S tyl / S tot <0.55 ···(9) S 411 / S tot >0.30 (10) S 411 / S tra ≧0.60 (11)

[0072] In the second embodiment, the area ratio S tyl / S tot is less than 0.55. Total area S tyl may be zero. Area ratio S tyl / S tot The upper limit of the area ratio S is determined as one of the parameters that indicates the degree of growth of the {411} orientation grains. tyl / S tot When the area ratio S is 0.55 or more, it indicates that the oriented grains having a Taylor factor of more than 2.9, which should be increased at the stage of strain-induced grain growth, are not sufficiently increased. In this case, the magnetic properties are not sufficiently improved. tyl / S tot is 0.40 or less, more preferably 0.30 or less. tyl / S tot Since it is preferable that is small, the lower limit is not specified and may be 0.00.

[0073] In the second embodiment, the area ratio S 411 / S tot is more than 0.30. Area ratio S 411 / S tot If the area ratio is less than 0.30, the magnetic properties are not sufficiently improved. 411 / S tot is 0.40 or more, more preferably 0.50 or more. 411 / S tot A situation where is 1.00 means that all of the crystal structure is composed of grains with the {411} orientation and no grains with other orientations are present, and the second embodiment is also intended to cover this situation.

[0074] In the second embodiment, as in the first embodiment, the relationship between the {411} oriented grains and the {411} oriented grains that are thought to have competed with the {411} oriented grains in strain-induced grain growth is also important. 411 / S tra When the area ratio S is sufficiently large, the dominance of the {411} oriented grains is ensured even in the situation of normal grain growth after strain-induced grain growth, resulting in good magnetic properties. 411 / S tra If the area ratio S is less than 0.60, the {411} oriented grains do not develop sufficiently due to strain-induced grain growth, and grains with small Taylor factors other than the {411} oriented grains grow to a considerable extent in the normal grain growth state after strain-induced grain growth, and the in-plane anisotropy of the magnetic properties also increases. 411 / S tra is set to 0.60 or more. It is preferable that the area ratio S 411 / S tra is 0.70 or more, more preferably 0.80 or more. 411 / S tra There is no need to particularly limit the upper limit, and all grains having a Taylor factor of 2.9 or less may be grains having the {411} orientation.

[0075] Although the range of the average crystal grain size is not particularly limited, if the average crystal grain size becomes too coarse, it becomes difficult to avoid the deterioration of the magnetic properties. For this reason, as in the first embodiment, the practical average crystal grain size of the {411} orientation grains, which are relatively coarse grains in the second embodiment, is preferably 500 μm or less. More preferably, the average crystal grain size of the {411} orientation grains is 400 μm or less, even more preferably 300 μm or less, and particularly preferably 200 μm or less. On the other hand, the lower limit of the average crystal grain size of the {411} orientation grains is preferably 40 μm or more, more preferably 60 μm or more, and even more preferably 80 μm or more, assuming that sufficient preferential growth of the {411} orientation is ensured.

[0076] [Characteristics] Because the chemical composition and metal structure of the non-oriented electrical steel sheet after final annealing are controlled as described above, it is possible to obtain excellent magnetic properties (low iron loss) not only on average in the rolling direction and width direction, but also on average all around (average of the rolling direction, width direction, directions at 45 degrees to the rolling direction, and directions at 135 degrees to the rolling direction). The rolling direction and width direction referred to here are the rolling direction and width direction of the obtained non-oriented electrical steel sheet.

[0077] The non-oriented electrical steel sheet of embodiment 2 has the best magnetic properties in the 45° direction among the three directions that form angles of 0°, 45°, and 90° with the rolling direction. In embodiment 2, the magnetic properties in the 45° direction are the average values ​​of the magnetic properties in the two directions that form angles of +45° and -45° with the rolling direction.

[0078] When the magnetic flux density of the non-oriented electrical steel sheet of the second embodiment was measured, the magnetic flux density B 50 is preferably 1.75 T or more. In the non-oriented electrical steel sheet according to embodiment 2, the magnetic flux density in the direction at 45° to the rolling direction is high, the sheet in-plane anisotropy is small, and a high magnetic flux density can be obtained even on the circumferential average (all-direction average).

[0079] In the non-oriented electrical steel sheet of embodiment 2, 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, B 50L and B. 50C The magnetic flux density is anisotropic, with the

[0080] In the non-oriented electrical steel sheet of embodiment 2, B 50D And B 50L and B 50C It is more preferable to satisfy the following formula (A) using the average value of

[0081] |B 50D -(B 50L +B 50C ) / 2|≦0.2 (A)

[0082] There is no particular lower limit to the value on the left side of the above formula (A), but it is preferably zero.

[0083] 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.

[0084] Magnetic measurements may be performed according to the methods described in JIS C 2550-1 (2011) and JIS C 2550-3 (2019), or according to the method described in JIS C 2556 (2015). If the sample is too small to be measured according to the above JIS standards, the electromagnetic circuit may be measured using a 55 mm square test piece conforming to JIS C 2556 (2015) or a device capable of measuring even smaller test pieces.

[0085] 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 process, a cold rolling process, an intermediate annealing process, a skin pass rolling process, and a final annealing process. Preferred conditions for each step will now be described. Hereinafter, in this embodiment, Ar 3 The temperature is the transformation temperature Ar 3 (℃).

[0086] (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.

[0087] 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.

[0088] In the heating process, it is preferable to heat the steel material having the above-mentioned chemical composition to 1000 to 1200° C. Specifically, the steel material is charged into a heating furnace or a soaking furnace and heated in the furnace. The holding time at the above heating temperature in the heating furnace or the soaking furnace is not particularly limited, but is, for example, 30 to 200 hours.

[0089] 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 using 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.

[0090] 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 produced by normal continuous casting. The slab is heated with Ar 3 The hot rolling is started in a temperature range where the steel structure becomes γ phase (hereinafter, this temperature range may be referred to as 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 where the steel structure has an α phase (hereinafter, this temperature range may be referred to as 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 Ar 3 Temperature above Ar 3 The rolling reduction in the temperature range below +20℃ is 10% or more. Furthermore, the finishing rolling temperature FT or higher is Ar 3 The reduction ratio in the temperature range below the rolling 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. There is no particular lower limit for the finish rolling temperature FT. For example, Ar 3 The temperature must be above -100℃.

[0091] Ar just before the final rolling in the α region 3 Rolling at temperatures above +20°C has little 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 {411} crystal orientation in the final product. Ar just before the final rolling in the α region 3 Temperature above Ar 3 If the rolling reduction ratio is less than 10% in the temperature range below +20°C, the accumulation of strain in the deformed γ grains before the phase transformation is insufficient, and coarse deformed α grains are formed, making it difficult for the final product to accumulate in the {411} crystal orientation. 3 Temperature above Ar 3 The rolling reduction in the temperature range of +20° C. or less is preferably 15% or more, and more preferably 20% or more. There is no upper limit to the total rolling reduction, but a reduction exceeding 40% places too much strain on the rolling mill, so the upper limit is preferably set at 40%. Final rolling temperature in the α region FT or higher Ar 3 If the total reduction rate in the temperature range below the FT temperature is less than 15%, the processed α grains after phase transformation from the processed γ grains cannot accumulate sufficient processing strain in the α region, and accumulation in the {411} crystal orientation in the final product becomes difficult. 3 The reduction in the temperature range below the temperature is preferably 20% or more, more preferably 25% or more. Although there is no upper limit to the total reduction, a reduction exceeding 40% places too much strain on the rolling mill, so the upper limit is preferably 40%. 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

[0092] 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 above rolling temperatures are determined by the competition between the temperature drop due to roll contact and cooling lubricant and the temperature rise due to processing, and the temperature reaches the specified judgment temperature (Ar 3 Temperature, or Ar 3 The present embodiment deals with such a situation 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 allows the determination of the temperature (Ar 3 Temperature, or Ar 3 +20°C) during the rolling pass, it is possible to determine the plate thickness at that point. 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:

[0093] It should be noted that the above assumption assumes that the exit temperature of the rolling pass is higher than the entry temperature. In other words, the entry temperature TPI of the pass is Ar 3 The temperature of the steel plate, which was below the Ar temperature, increases due to heat generated during processing during the pass. 3 Even in a situation where the discharge temperature is higher than the TPO temperature, the γ region (Ar 3 Temperature above Ar 3 It is determined that the material was rolled at a temperature below +20°C. Also, Ar 3 It is also conceivable that temperature fluctuations 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 α region 3 and γ region 2 meet the conditions of this embodiment, it is possible to obtain the disclosed steel sheet.

[0094] 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 Ar 3 It is preferable that the temperature is less than 100° C.

[0095] Thereafter, the hot-rolled steel sheet is coiled without annealing the hot-rolled sheet. The temperature during coiling is preferably more than 450°C and less than 650°C. By coiling the hot-rolled steel sheet after hot rolling at more than 450°C and less than 650°C, the strain introduced by the α region hot rolling is moderately relaxed, so that the crystal structure before cold rolling can be refined, which affects the recrystallization behavior during intermediate annealing and promotes the development of the {411} crystal orientation rather than the {100} crystal orientation at the intermediate annealed sheet stage. An effect of enriching the {411} crystal orientation, which has excellent magnetic properties, during bulging is obtained. The temperature during coiling is more preferably 500°C to 600°C, and even more preferably 520°C to 580°C.

[0096] (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%. 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.

[0097] In addition, when cold rolling is performed, it is preferable to perform one or more passes of rolling so that the rolling shape ratio is 5.0 or less. By setting the rolling shape ratio to 5.0 or less, shear strain is added, and the formation of the {411} crystal orientation during cold rolling is promoted. From this viewpoint, it is preferable to set it to 4.5 or less, and more preferably to set it to 4.0 or less. There is no particular lower limit for the rolling shape ratio, but since it is difficult to control it to less than 1.0, it is preferable to set it to this as the lower limit. The shape ratio is defined by the following formula (a). Γ=ld / hm (a) In the above formula (a), each symbol is defined as follows. Γ: Rolling shape ratio ld: Projected contact arc length hm: average plate thickness

[0098] Moreover, the above ld and hm are calculated from the following equations (b) and (c). ld = √(R × (Hh)) (b) hm = (H + 2h) / 3 (c) In the above formulas (b) and (c), each symbol is defined as follows. R: Roll radius H: Inlet thickness (thickness before entering the rolling mill for that pass) h: Exit thickness (thickness of the plate when it leaves the rolling mill in that pass)

[0099] (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 less than 900°C. The temperature of intermediate annealing is preferably 800°C or less, more preferably 750°C or less. If the temperature of intermediate annealing is 900°C or more, 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. In addition, if the temperature of intermediate annealing is too low and sufficient recrystallization does not occur, 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 600°C or more, more preferably 700°C or more. The temperatures described here are based on the premise of continuous annealing, and the intermediate annealing time 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.

[0100] (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 with the strain difference as the driving force. This eating phenomenon generated with the strain difference as the driving force is called strain-induced grain boundary migration (hereinafter referred to as SIBM). The reduction ratio of skin pass rolling is preferably 5% to less than 25%. If the reduction ratio is less than 5%, the amount of strain is too small, so strain-induced grain boundary migration (hereinafter referred to as 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 25% or more, the amount of strain becomes too large, and recrystallization nucleation (hereinafter referred to as 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 the viewpoint of increasing the average magnetic flux density in the sheet plane and reducing the anisotropy, the reduction ratio of skin pass rolling is more preferably 5% to 15%.

[0101] In the case of non-oriented electrical steel sheets, when it is desired to have the strain distribution described above, when the reduction ratio (%) during skin pass rolling is RR2, it is preferable to adjust the reduction ratios of cold rolling and skin pass rolling so as to satisfy 5 < RR2 < 25.

[0102] Here, the reduction ratio RR1 (%) in cold rolling is defined as follows. Reduction ratio RR1 (%) = (1 - thickness of the sheet after rolling in the final pass of cold rolling / thickness of the sheet before rolling in the first pass of cold rolling) × 100 Also, 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

[0103] (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. The annealing conditions can be appropriately set by a person skilled in the art while confirming the occurrence of SIBM, and are not particularly limited, but examples include annealing at 700 to 950°C for 1 to 100 seconds in the case of continuous annealing and annealing at 650 to 850°C for 0.5 to 2 hours in the case of batch annealing.

[0104] The non-oriented electrical steel sheet according to the present embodiment can be manufactured as described above. However, this manufacturing method is merely one example of a method for manufacturing the non-oriented electrical steel sheet according to the present embodiment, and is not intended to limit the manufacturing method.

[0105] As described above, the non-oriented electrical steel sheet according to this embodiment can be manufactured. The final annealing process can be performed after skin pass rolling, for example, at a steel sheet manufacturer in the form of a steel sheet coil or as a cut sheet. Alternatively, after skin pass rolling, the steel sheet can be shipped without the final annealing process, and the motor manufacturer can process the steel sheet into a predetermined shape as a motor core, laminate the steel sheet, and then perform the final annealing in the core shape. In the latter case, this process can also be performed as "strain relief annealing" that is generally performed on motor cores at motor manufacturers. The final annealing may be performed two or more times by both the steel sheet manufacturer and the motor manufacturer. By adjusting the final annealing after skin pass rolling, the amount of remaining strain, the grain size, and the degree of development of the {411} orientation can be adjusted. Steel sheets with a large amount of remaining strain or a relatively small grain size have high strength, and are particularly suitable for use as non-oriented electrical steel sheets for rotor cores to suppress deformation due to centrifugal force accompanying the rotation of the core. On the other hand, steel sheets with sufficient strain release and coarse grain size are particularly suitable for use as non-oriented electrical steel sheets for stator cores to suppress iron loss.

[0106] 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

[0107] 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.

[0108] The molten steel was cast to produce an ingot having the composition shown in Table 1 below. In addition, "Co, etc." in Table 1 indicates the respective contents of Co, Pt, Pb, and Au. The produced ingot was then hot-rolled under the conditions shown in Table 1 to obtain a hot-rolled sheet. Next, it was cold-rolled under the conditions shown in Table 1 to obtain a cold-rolled sheet.

[0109] The cold-rolled sheet was subjected to intermediate annealing in a non-oxidizing atmosphere at the temperature shown in Table 2 for 30 seconds, and then subjected to a second cold rolling (skin pass rolling) at the rolling reduction shown in Table 2.

[0110] Next, to investigate the texture, a part of the steel plate was cut out, the cut out test piece was processed to reduce its thickness to 7 / 8, and the processed surface (the polished surface where the steel plate was polished to 1 / 8 from the plate side) was observed by EBSD (step interval: 0.3 μm) as described above. The areas and average KAM values ​​of the orientation grains of the types shown in Table 3 were obtained by EBSD observation.

[0111] The steel sheets were then subjected to final annealing at 800°C for 2 hours. Measurement samples were taken from the steel sheets after final annealing, with 55 mm square pieces. Two samples were taken: one with one side parallel to the rolling direction, and the other with one side tilted at 45 degrees to the rolling direction. The samples were taken using a shearing machine. Next, to investigate the texture, a part of the steel plate was cut out, the cut out test piece was processed to reduce its thickness to 7 / 8, and the processed surface (the polished surface where the steel plate was polished to 1 / 8 from the plate side) was observed by EBSD (step interval: 2.0 μm) as described above. The areas and average KAM values ​​of the orientation grains of the types shown in Table 3 were obtained by EBSD observation. 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 was measured in accordance with JISC2556 (2015). The measurement results are shown in Table 3. The "average value" shown in Table 3 is the magnetic flux density B 50 The magnetic flux density B in the rolling direction, 90° direction to the rolling direction, and 45° (135°) direction to the rolling direction is the average value of the entire circumference. 50 (average value).

[0112] The rollability was evaluated as follows: In a 1 m long longitudinal region centered on a position 10 m in the longitudinal direction from the outermost longitudinal tip of the cold-rolled sheet coil (top part), a position half the total length of the coil in the longitudinal direction from the outermost longitudinal tip of the coil (middle part), and a position 10 m in the longitudinal direction 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", and 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.

[0113] [Table 1-1]

[0114] [Table 1-2]

[0115] [Table 2-1]

[0116] [Table 2-2]

[0117] [Table 3-1]

[0118] [Table 3-2]

[0119] For the No. 12 steel sheet, the test piece was processed to reduce its thickness to half, and the processed surface was observed by EBSD in the manner described above to determine the area and average KAM value of the oriented grains of the types shown in Table 4. The results are shown in Table 4 together with the magnetic properties and rollability.

[0120] [Table 4] [Industrial Applicability]

[0121] INDUSTRIAL APPLICABILITY The present disclosure makes it possible to provide a non-oriented electrical steel sheet having small in-plane anisotropy and excellent magnetic properties averaged all around (averaged in all directions), which is extremely useful in industry.

[0122] The disclosure of Japanese Patent Application No. 2023-001935 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.< / uvw> < / uvw>

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: 0.0% 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% 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; Furthermore, when observed by EBSD on a surface parallel to the steel sheet surface, the total area is S tot , the area of ​​the {411} oriented grain is S 411 , the area of ​​the {100} oriented grain is S 100 The area of ​​the oriented grains whose Taylor factor M according to the following formula (2) is greater than 2.9 is defined as S tyl The total area of ​​oriented grains having the Taylor factor M of 2.9 or less is defined as S tra , the average KAM value of the {411} oriented grains is K 411 The average KAM value of the oriented grains having the Taylor factor M of more than 2.9 is K tyl In this case, the following formula (3) and formulas (4) to (7) are satisfied: The average KAM value is a non-oriented electrical steel sheet in which the limit for inclusion in the KAM value is an orientation difference of 5° or less with adjacent pixels, and the average value of the calculated orientation differences between the most adjacent measurement points is taken as the average value. Ar ３ (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.-]-120×([M]+[[[[[[])-46×([[[[[Ni]) ・・・(1) M=(cosφ×cosλ) -1 ・・・(2) S 411 / S 100 >1.00 ・・・(3) 0.20≦S tyl / S tot ≦0.85 ・・・(4) 0.05≦S 411 / S tot ≦0.80 ・・・(5) S 411 / S tra ≧0.50 ・・・(6) K 411 / K tyl ≦0.990 ・・・(7) Here, in formula (2), φ represents the angle between the stress vector and the slip direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the slip plane of the crystal.

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: 0.0% 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% 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; Furthermore, when observed by EBSD on a surface parallel to the steel sheet surface, the total area is S tot , the area of ​​the {411} oriented grain is S 411 , the area of ​​the {100} oriented grain is S 100 The area of ​​the oriented grains whose Taylor factor M according to the following formula (2) is greater than 2.9 is defined as S tyl The total area of ​​oriented grains having the Taylor factor M of 2.9 or less is defined as S tra , the average KAM value of the {411} oriented grains is K 411 The average KAM value of the oriented grains having the Taylor factor M of more than 2.9 is K tyl In this case, the following formula (3) and formulas (4) to (7) are satisfied: The average KAM value is a non-oriented electrical steel sheet in which the limit for inclusion in the KAM value is an orientation difference of 5° or less with adjacent pixels, and the average value of the calculated orientation differences between the most adjacent measurement points is taken as the average value. Ar ３ (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.-]-120×([M]+[[[[[[])-46×([[[[[Ni]) ・・・(1) M=(cosφ×cosλ) -1 ・・・(2) S 411 / S 100 >1.00 ・・・(3) 0.20≦S tyl / S tot ≦0.85 ・・・(4) 0.05≦S 411 / S tot ≦0.80 ・・・(5) S 411 / S tra ≧0.50 ・・・(6) K 411 / K tyl ≦0.990 ・・・(7) Here, in formula (2), φ represents the angle between the stress vector and the slip direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the slip plane of the crystal.

3. 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: 0.0% 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% 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; Furthermore, when observed by EBSD on a surface parallel to the steel sheet surface, the total area is S tot , the area of ​​the {411} oriented grain is S 411 , the area of ​​the {100} oriented grain is S 100 The area of ​​the oriented grains whose Taylor factor M according to the following formula (2) is greater than 2.9 is defined as S tyl The total area of ​​oriented grains having the Taylor factor M of 2.9 or less is defined as S tra A non-oriented electrical steel sheet that satisfies the following formulas (8) to (11): Ar ３ (℃)=1020-325×[C]+33×[Si]+287×[P]+80×[sol.-]-120×([M]+[[[[[[])-46×([[[[[Ni]) ・・・(1) M=(cosφ×cosλ) -1 ・・・(2) S 411 / S 100 >2.00 ・・・(8) S tyl / S tot <0.55 ・・・(9) S 411 / S tot >0.30 ・・・(10) S 411 / S tra ≧0.60 ・・・(11) Here, in formula (2), φ represents the angle between the stress vector and the slip direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the slip plane of the crystal.

4. 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: 0.0% 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% 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; Furthermore, when observed by EBSD on a surface parallel to the steel sheet surface, the total area is S tot , the area of ​​the {411} oriented grain is S 411 , the area of ​​the {100} oriented grain is S 100 The area of ​​the oriented grains whose Taylor factor M according to the following formula (2) is greater than 2.9 is defined as S tyl The total area of ​​oriented grains having the Taylor factor M of 2.9 or less is defined as S tra A non-oriented electrical steel sheet that satisfies the following formulas (8) to (11): Ar ３ (℃)=1020-325×[P]+33×[Si]+287×[P]+80× [sol. Al]-120×([Mn]+[Mo]+[Cu])-46×([Cr]+[Ni])...(1) M=(cosφ×cosλ) -1 ・・・(2) S 411 / S 100 >2.00 ・・・(8) S tyl / S tot <0.55 ・・・(9) S 411 / S tot >0.30 ・・・(10) S 411 / S tra ≧0.60 ・・・(11) Here, in formula (2), φ represents the angle between the stress vector and the slip direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the slip plane of the crystal.

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