Non-oriented electromagnetic steel sheet and method for manufacturing the same

Abstract

The non-oriented electromagnetic steel sheet has a prescribed chemical composition, and when observed by EBSD in a plane parallel to the surface of the steel sheet, in a case where the total area is set as S tot , the area of {100} oriented grains is set as S 100 , the area of oriented grains whose Taylor factor M exceeds 2.8 is set as S tyl , the total area of oriented grains whose Taylor factor M is 2.8 or less is set as S tra , the average KAM value of {100} oriented grains is set as K 100 , the average KAM value of oriented grains whose Taylor factor M exceeds 2.8 is set as K tyl , 0.20 ≦ S tyl / S tot ≦ 0.85, 0.05 ≦ S 100 / S tot ≦ 0.80, S 100 / S tra ≧ 0.5, K 100 / K tyl ≦ 0.990.

Description

Technical Field

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

[0002] This application claims priority based on Japanese Patent Application No. 2021-046004 filed in Japan on March 19, 2021, the contents of which are incorporated herein by reference. Background Art

[0003] Non-oriented electrical steel sheets are used, for example, in the cores of motors. Non-oriented electrical steel sheets are required to have excellent magnetic properties in a direction parallel to the sheet surface, such as low iron loss and high magnetic flux density.

[0004] Therefore, it is advantageous to control the texture of the steel sheet so that the easy magnetization axes (<100> orientation) of the crystals are aligned in the in-plane direction. Generally speaking, the {100} orientation, which has a large number of easy magnetization axes in the in-plane direction, is a particularly preferred orientation, while the {111} orientation, which has no easy magnetization axes in the in-plane direction, is a typical orientation to be avoided. Regarding this type of texture control, for example, the techniques described in Patent Documents 1 to 5 disclose techniques for controlling the {100} orientation, the {110} orientation, and the {111} orientation.

[0005] Various methods are conceivable for controlling texture, including the use of strain-induced grain growth. Under specific conditions, strain-induced grain growth can suppress the accumulation of the {111} orientation and has been effectively utilized in non-oriented electrical steel sheets. These techniques are also disclosed in Patent Documents 6 to 10.

[0006] However, when these non-oriented electrical steel sheets are sheared, there is a possibility that the characteristics may vary.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-193754

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-111658

[0011] Patent Document 3: International Publication No. 2016 / 148010

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 2018-3049

[0013] Patent Document 5: International Publication No. 2015 / 199211

[0014] Patent Document 6: Japanese Patent Application Laid-Open No. 8-143960

[0015] Patent Document 7: Japanese Patent Application Laid-Open No. 2002-363713

[0016] Patent Document 8: Japanese Patent Application Laid-Open No. 2011-162821

[0017] Patent Document 9: Japanese Patent Application Laid-Open No. 2013-112853

[0018] Patent Document 10: Japanese Patent No. 4029430 Summary of the Invention

[0019] Technical problem to be solved by the invention

[0020] In view of the above-mentioned problems, an object of the present invention is to provide a non-oriented electrical steel sheet that can obtain excellent magnetic properties (low iron loss, etc.) even after shearing, and a method for producing the same.

[0021] Technical means for solving technical problems

[0022] The inventors of the present invention have studied a technique for utilizing strain-induced grain growth to form a texture preferred for non-oriented electrical steel sheets, and the properties of the resulting steel sheets. They discovered that in non-oriented electrical steel sheets utilizing strain-induced grain growth, the properties (particularly iron loss) can vary significantly depending on the processing conditions when cutting samples for property evaluation. A detailed examination of this phenomenon suggests that the roughness of the sample cross-section, when the properties are low, may affect the fracture behavior during shearing.

[0023] The inventors of the present invention have studied in detail the relationship between the state of the cross section and the crystal structure, and have clarified that the characteristic is that the crystal structure in the steel plate with a relatively rough cross section is mixed grains, and the grain sizes of the {100}-oriented grains and {110}-oriented grains that are the orientations eroded during strain-induced grain growth are different from the grain sizes of the {111}-oriented grains that are the orientations eroded.

[0024] The inventors of the present invention conducted intensive research to solve the above-mentioned technical problems. As a result, they clarified that it is possible to produce non-oriented electrical steel sheets with excellent magnetic properties, in which {100}-oriented grains are preferentially grown during strain-induced grain growth. To suppress the adverse effects of shear on magnetic properties, it is important to maintain an appropriate area and area ratio of {100}-oriented grains to {111}-oriented grains when viewed in a plane parallel to the steel sheet surface.

[0025] Furthermore, it was clarified that in order to manufacture such non-oriented electrical steel sheets, it is important to control the area and area ratio of oriented grains with a small Taylor factor and oriented grains with a large Taylor factor when viewed parallel to the steel sheet surface, as well as the amount of strain applied thereto, within a predetermined range at the stage of applying strain that causes strain induction, so as to allow strain-induced grain growth to occur.

[0026] The inventors of the present invention have conducted further intensive research based on this knowledge, and have come up with the following inventions. [1]

[0028] The non-oriented electrical steel sheet according to one embodiment of the present invention has the following chemical composition:

[0029] In mass%, contains

[0030] Si: 1.50% to 4.00%,

[0031] One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au: less than 2.50% in total,

[0032] C: 0.0100% or less,

[0033] sol.Al: 4.00% or less,

[0034] S: 0.0400% or less,

[0035] N: 0.0100% or less,

[0036] Sn: 0.00% to 0.40%,

[0037] Sb: 0.00% to 0.40%,

[0038] P: 0.00%~0.40%,

[0039] Cr: 0.001% to 0.100%,

[0040] B: 0.0000%~0.0050%,

[0041] O: 0.0000% to 0.0200%, and

[0042] 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,

[0043] When the Mn content is expressed as [Mn] by mass%, the Ni content is expressed as [Ni] by mass%, the Co content is expressed as [Co] by mass%, the Pt content is expressed as [Pt] by mass%, the Pb content is expressed as [Pb] by mass%, the Cu content is expressed as [Cu] by mass%, the Au content is expressed as [Au] by mass%, the Si content is expressed as [Si] by mass%, and the sol.Al content is expressed as [sol.Al] by mass%, the following formula (1) is satisfied:

[0044] The rest is composed of Fe and impurities.

[0045] Furthermore, when observing by EBSD in a plane parallel to the steel plate surface, the total area is defined as S tot , let the area of ​​{100} oriented grains be S 100 The area of ​​oriented grains with a Taylor factor M exceeding 2.8 based on the following formula (2) is defined as S tyl The total area of ​​the oriented grains with the Taylor factor M being less than 2.8 is defined as S tra The average KAM value of the {100} oriented grains is set as K 100 The average KAM value of the oriented grains with Taylor factor M higher than 2.8 is set as K tyl In the case of , the following equations (3) to (6) are satisfied:

[0046] ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])≦0.00%···(1)

[0047]

[0048] 0.20≦S tyl / S tot ≦0.85···(3)

[0049] 0.05≦S 100 / S tot ≦0.80···(4)

[0050] S 100 / S tra ≧0.50···(5)

[0051] K 100 / K tyl ≦0.990···(6)

[0052] Here, in formula (2) represents the angle between the stress vector and the sliding direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the sliding surface of the crystal. [2]

[0054] Also, the non-oriented electromagnetic steel sheet of the above [1], further, when the average KAM value of the oriented grains with the Taylor factor M of 2.8 or less is set as K tra satisfies the following (7) formula

[0055] K 100 / K tra <1.010 (7). [3]

[0057] Also, the non-oriented electromagnetic steel sheet of the above [1] or 2, further, when the area of the {110} oriented grains is set as S 110 satisfies the following (8) formula

[0058] S 100 / S 110 ≧1.00 (8)

[0059] Here, the (8) formula is set as even if the area ratio S 100 / S 110 diverges to infinity, it is also established. [4]

[0061] Also, the non-oriented electromagnetic steel sheet of any one of the above [1] to [3], further, when the average KAM value of the {110} oriented grains is set as K 110 satisfies the following (9) formula.

[0062] K 100 / K 110 <1.010 (9)

[0063] [5] The non-oriented electromagnetic steel sheet of the other aspect of the present application has the following chemical components:

[0064] contains, in mass%,

[0065] Si: 1.50% to 4.00%,

[0066] one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total less than 2.50%,

[0067] C: 0.0100% or less,

[0068] sol. Al: 4.00% or less,

[0069] S: 0.0400% or less,

[0070] N: 0.0100% or less,

[0071] Sn: 0.00% to 0.40%,

[0072] Sb: 0.00% to 0.40%,

[0073] P: 0.00%~0.40%,

[0074] Cr: 0.001% to 0.100%,

[0075] B: 0.0000%~0.0050%,

[0076] O: 0.0000% to 0.0200%, and

[0077] 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,

[0078] When the Mn content is expressed as [Mn] by mass%, the Ni content is expressed as [Ni] by mass%, the Co content is expressed as [Co] by mass%, the Pt content is expressed as [Pt] by mass%, the Pb content is expressed as [Pb] by mass%, the Cu content is expressed as [Cu] by mass%, the Au content is expressed as [Au] by mass%, the Si content is expressed as [Si] by mass%, and the sol.Al content is expressed as [sol.Al] by mass%, the following formula (1) is satisfied:

[0079] The rest is composed of Fe and impurities.

[0080] Furthermore, when observing by EBSD in a plane parallel to the steel plate surface, the total area is defined as S tot , let the area of ​​{100} oriented grains be S 100 The area of ​​oriented grains with a Taylor factor M greater than 2.8 based on the following formula (2) is defined as S tyl The total area of ​​the oriented grains with the Taylor factor M being less than 2.8 is defined as S tra The average KAM value of the {100} oriented grains is set as K 100 The average KAM value of the oriented grains with Taylor factor M exceeding 2.8 is set as K tyl , the average crystal grain size of the observation area is set as d ave The average grain size of the {100} oriented grains is set to d 100 The average crystal grain size of the oriented grains with the Taylor factor M exceeding 2.8 is set as d tyl In the case of , the following equations (10) to (15) are satisfied:

[0081] ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])≦0%···(1)

[0082]

[0083] S tyl / S tot ≦0.70···(10)

[0084] 0.20≦S 100 / S tot ···(11)

[0085] S 100 / S tra ≧0.55···(12)

[0086] K 100 / K tyl ≦1.010···(13)

[0087] d 100 / d ave >1.00···(14)

[0088] d 100 / d tyl >1.00···(15)

[0089] Here, in formula (2) represents the angle between the stress vector and the sliding direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the sliding surface of the crystal. [6]

[0091] Alternatively, the non-oriented electrical steel sheet described in [5] may further include an average KAM value of oriented grains having a Taylor factor M of 2.8 or less as K tra When , the following formula (16) is satisfied

[0092] K 100 / K tra <1.010···(16). [7]

[0094] Alternatively, the non-oriented electrical steel sheet described in [5] or [6] may further include the following steps: setting the average crystal grain size of the oriented grains having the Taylor factor M of 2.8 or less to d tra When , the following formula (17) is satisfied

[0095] d 100 / d tra >1.00···(17). [8]

[0097] Also, the non-oriented electromagnetic steel sheet according to any one of the above [5] to [7], further satisfies the following (18) when the area of the {110} oriented grains is set as S 110

[0098] S 100 / S 110 ≧ 1.00 ··· (18)

[0099] Here, the (18) is also established even if the area ratio S 100 / S 110 diverges to infinity. [9]

[0101] Also, the non-oriented electromagnetic steel sheet according to any one of the above [5] to [8], further satisfies the following (19) when the average KAM value of the {110} oriented grains is set as K 110

[0102] K 100 / K 110 < 1.010 ··· (19).

[10]

[0104] The manufacturing method of the non-oriented electromagnetic steel sheet according to the aspect of the present application is the manufacturing method of the non-oriented electromagnetic steel sheet according to any one of the above [5] to [9],

[0105] The non-oriented electromagnetic steel sheet according to any one of the above [1] to [4] is heat treated at a temperature of 700°C to 950°C for 1 second to 100 seconds.

[11]

[0107] The non-oriented electromagnetic steel sheet according to the other aspect of the present application has the following chemical components:

[0108] contains, in mass%,

[0109] Si: 1.50% to 4.00%,

[0110] one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total less than 2.50%,

[0111] C: 0.0100% or less,

[0112] sol. Al: 4.00% or less,

[0113] S: 0.0400% or less,

[0114] N: 0.0100% or less, ​​

[0115] Sn: 0.00% to 0.40%,

[0116] Sb: 0.00% to 0.40%,

[0117] P: 0.00%~0.40%,

[0118] Cr: 0.001% to 0.100%,

[0119] B: 0.0000%~0.0050%,

[0120] O: 0.0000% to 0.0200%, and

[0121] 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,

[0122] When the Mn content is expressed as [Mn] by mass%, the Ni content is expressed as [Ni] by mass%, the Co content is expressed as [Co] by mass%, the Pt content is expressed as [Pt] by mass%, the Pb content is expressed as [Pb] by mass%, the Cu content is expressed as [Cu] by mass%, the Au content is expressed as [Au] by mass%, the Si content is expressed as [Si] by mass%, and the sol.Al content is expressed as [sol.Al] by mass%, the following formula (1) is satisfied:

[0123] The rest is composed of Fe and impurities.

[0124] Furthermore, when observing by EBSD in a plane parallel to the steel plate surface, the total area is defined as S tot , let the area of ​​{100} oriented grains be S 100 The area of ​​oriented grains with a Taylor factor M greater than 2.8 based on the following formula (2) is defined as S tyl The total area of ​​the oriented grains with the Taylor factor M being less than 2.8 is defined as S tra , the average crystal grain size of the observation area is set as d ave The average grain size of the {100} oriented grains is set to d 100 The average crystal grain size of the oriented grains with Taylor factor M higher than 2.8 is set as d tyl In the case of , the following equations (20) to (24) are satisfied:

[0125] ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])≦0%···(1)

[0126]

[0127] S tyl / S tot <0.55···(20)

[0128] S 100 / S tot >0.30···(21)

[0129] S 100 / S tra ≧0.60···(22)

[0130] d 100 / d ave ≧0.95···(23)

[0131] d 100 / d tyl ≧0.95···(24)

[0132] Here, in formula (2) represents the angle between the stress vector and the sliding direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the sliding surface of the crystal.

[12]

[0134] Alternatively, the non-oriented electrical steel sheet described in

[11] may further include an average grain size of oriented grains having a Taylor factor M of 2.8 or less set to d tra When , the following formula (25) is satisfied

[0135] d 100 / d tra ≧0.95···(25)

[0136] Here, in formula (2) represents the angle between the stress vector and the sliding direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the sliding surface of the crystal.

[13]

[0138] Another embodiment of the present invention provides a method for producing a non-oriented electrical steel sheet.

[0139] The non-oriented electrical steel sheet according to any one of [1] to [9] is heat treated at 950°C to 1050°C for 1 to 100 seconds, or at 700°C to 900°C for more than 1000 seconds.

[0140] Effects of the Invention

[0141] According to the above aspect of the present application, it is possible to provide a non-oriented electromagnetic steel sheet and a manufacturing method thereof, which has excellent magnetic properties even after shearing processing because the area and the area ratio of the specific crystal orientation in the cross section parallel to the sheet surface are appropriate. DETAILED DESCRIPTION

[0142] Hereinafter, an embodiment of the present application will be described. The non-oriented electromagnetic steel sheet of the present embodiment is manufactured by subjecting a steel material manufactured by casting or the like to a hot rolling process, a hot rolled sheet annealing process, a cold rolling process, an intermediate annealing process, and a skin pass rolling process. At this stage, the steel sheet has a microstructure described in Embodiment 1 described later.

[0143] Further, thereafter, the steel sheet is manufactured by subjecting to a first heat treatment process. At this stage, the steel sheet has a microstructure described in Embodiment 2 described later.

[0144] Further, the non-oriented electromagnetic steel sheet after the skin pass rolling or after the first heat treatment is manufactured by subjecting to a second heat treatment. At this stage, the steel sheet has a microstructure described in Embodiment 3 described later.

[0145] By the heat treatment after the skin pass rolling (the first heat treatment and / or the second heat treatment), the steel sheet is subjected to strain-induced grain growth, and thereafter, normal grain growth. The strain-induced grain growth and the normal grain growth can be performed in the first heat treatment process or in the second heat treatment process.

[0146] The steel sheet after the skin pass rolling is the original sheet of the steel sheet after the strain-induced grain growth and the original sheet of the steel sheet after the normal grain growth. Further, the steel sheet after the strain-induced grain growth is the original sheet of the steel sheet after the normal grain growth. Hereinafter, the steel sheet after the skin pass rolling, the steel sheet after the strain-induced grain growth, and the steel sheet after the normal grain growth are described as the non-oriented electromagnetic steel sheet regardless of before or after the heat treatment.

[0147] Regarding the chemical components, there is no change by the hot rolling process, the hot rolled sheet annealing process, the cold rolling process, the intermediate annealing process, the skin pass rolling process, the first heat treatment process, and the second heat treatment process.

[0148] First, the chemical components of the steel material used in the non-oriented electromagnetic steel sheet and the method of manufacturing the same according to the present embodiment will be described. In the following description, the unit of the content of each element included in the non-oriented electromagnetic steel sheet or the steel material, i.e., "%" means "mass %" unless otherwise specified. The non-oriented electromagnetic steel sheet and the steel material according to the present embodiment have the following chemical components, containing: Si: 1.50% to 4.00%, one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total less than 2.50%, C: 0.0100% or less, sol. Al: 4.00% or less, P: 0.00% to 0.40%, S: 0.0400% or less, N: 0.0100% or less, Sn: 0.00% to 0.40%, Sb: 0.00% to 0.40%, Cr: 0.001% to 0.100%, B: 0.0000% to 0.0050%, O: 0.0000% to 0.0200%, and one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: total 0.0000 to 0.0100%, and the remainder consisting of Fe and impurities. As the impurities, substances included in raw materials such as ores or scrap materials, and substances included in the manufacturing process are exemplified.

[0149] (Si: 1.50% to 4.00%)

[0150] Si increases the electrical resistance, reduces the eddy current loss, reduces the iron loss, increases the yield ratio, and improves the blanking workability for the core. When the content of Si is less than 1.50%, these effects cannot be sufficiently obtained. Therefore, the content of Si is set to 1.50% or more. The content of Si is preferably 2.00% or more, more preferably 2.10% or more, and even more preferably 2.30% or more.

[0151] On the other hand, when the content of Si is higher than 4.00%, the magnetic flux density decreases, the blanking workability decreases due to excessive increase in hardness, and cold rolling becomes difficult. Therefore, the content of Si is set to 4.00% or less.

[0152] (one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, Au: total less than 2.50%)

[0153] These elements are austenite phase (γ phase) stabilizing elements. If they are contained in large amounts, ferrite-austenite transformation (hereinafter referred to as α-γ transformation) will occur during heat treatment of the steel sheet. The effect of the non-oriented electrical steel sheet of this embodiment is believed to be exerted by controlling the area and area ratio of specific crystal orientations in the cross section parallel to the steel sheet surface. However, if α-γ transformation occurs during heat treatment, the above area and area ratio will change significantly due to the phase transformation, and the specified metallographic structure cannot be obtained. Therefore, the total content of one or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au is less than 2.50%. The total content is preferably less than 2.00%, more preferably less than 1.50%. The lower limit of the total content of these elements is not particularly limited (it can also be 0.00%), but with respect to Mn, it is preferably set to 0.10% or more to suppress the fine precipitation of MnS that deteriorates magnetic properties.

[0154] Furthermore, as a condition for not causing the α-γ transformation, the following condition is also satisfied. That is, when the Mn content is expressed as [Mn] by mass%, the Ni content is expressed as [Ni] by mass%, the Co content is expressed as [Co] by mass%, the Pt content is expressed as [Pt] by mass%, the Pb content is expressed as [Pb] by mass%, the Cu content is expressed as [Cu] by mass%, the Au content is expressed as [Au] by mass%, the Si content is expressed as [Si] by mass%, and the sol.Al content is expressed as [sol.Al] by mass%, the following formula (1) is satisfied.

[0155] ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])≦0.00%···(1)

[0156] (C: 0.0100% or less)

[0157] C increases iron loss and causes magnetic aging. Therefore, the lower the C content, the better. This phenomenon becomes more pronounced when the C content exceeds 0.0100%. Therefore, the C content is set to 0.0100% or less. The lower limit of the C content is not particularly limited, but considering the cost of decarburization during refining, the C content is preferably set to 0.0005% or more.

[0158] (sol.Al: 4.00% or less)

[0159] Sol.Al increases electrical resistance, reduces eddy current loss, and lowers iron loss. Sol.Al also helps to increase the relative size of magnetic flux density B50 relative to the saturation magnetic flux density. Here, the so-called magnetic flux density B50 refers to the magnetic flux density in a magnetic field of 5000A / m. When the sol.Al content is less than 0.0001%, these effects cannot be fully achieved. In addition, Al also has the effect of promoting desulfurization in steelmaking. Therefore, when obtaining the above-mentioned effects, the sol.Al content is preferably set to 0.0001% or more. The sol.Al content is more preferably 0.30% or more.

[0160] On the other hand, if the sol.Al content exceeds 4.00%, the magnetic flux density decreases, the yield ratio decreases, and the blanking workability decreases. Therefore, the sol.Al content is set to 4.00% or less. The sol.Al content is preferably 2.50% or less, and more preferably 1.50% or less.

[0161] (S: 0.0400% or less)

[0162] S is not an essential element and is contained in steel as an impurity, for example. S hinders recrystallization and grain growth during annealing through the precipitation of fine MnS. Therefore, the lower the S content, the better. The increase in iron loss and the decrease in magnetic flux density caused by such obstruction of recrystallization and grain growth are significant when the S content is higher than 0.0400%. Therefore, the S content is set to 0.0400% or less. The S content is preferably 0.0200% or less, more preferably 0.0100% or less. The lower limit of the S content is not particularly limited, but based on the cost of desulfurization treatment during refining, the S content is preferably 0.0003% or more.

[0163] (N: 0.0100% or less)

[0164] 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. The lower limit of the N content is not particularly limited, but considering the cost of denitrification treatment during refining, the N content is preferably set to 0.0010% or more.

[0165] (Sn: 0.00% to 0.40%, Sb: 0.00% to 0.40%, P: 0.00% to 0.40%)

[0166] Excessive inclusion of Sn or Sb will cause steel embrittlement. Therefore, the Sn content and Sb content are both set to 0.40% or less. Furthermore, excessive inclusion of P will cause steel embrittlement. Therefore, the P content is set to 0.40% or less.

[0167] On the other hand, Sn and Sb have an effect of improving the texture after cold rolling and recrystallization, and increasing the magnetic flux density. In addition, P is an element effective for securing the hardness of the steel sheet after recrystallization. Therefore, these elements can be contained as needed. In this case, it is preferable to contain one or more selected from the group consisting of 0.02% to 0.40% of Sn, 0.02% to 0.40% of Sb, and 0.02% to 0.40% of P.

[0168] (Cr: 0.001% to 0.100%)

[0169] Cr combines with oxygen in the steel to form Cr2O3. This Cr2O3 contributes to the improvement of the texture. In order to obtain the above effect, the Cr content is set to 0.001% or more.

[0170] On the other hand, if the Cr content exceeds 0.100%, the Cr2O3 hinders the grain growth at the time of annealing, the crystal grain size becomes fine, and this becomes a cause of an increase in the iron loss. Therefore, the Cr content is set to 0.100% or less.

[0171] (More than one selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: total is 0.0100% or less)

[0172] Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd react with S in the molten steel at the time of casting of the molten steel to form precipitates of sulfides or sulfides and oxides. Hereinafter, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd will be sometimes collectively referred to as "coarse precipitate forming elements". The particle diameter of the precipitates of the coarse precipitate forming elements is about 1 μm to 2 μm, which is significantly larger than the particle diameter (about 100 nm) of the fine precipitates of MnS, TiN, AlN, and the like. Therefore, these fine precipitates adhere to the precipitates of the coarse precipitate forming elements, and do not easily hinder the growth of the grains in the strain-induced grain growth. In order to sufficiently obtain these effects, it is preferable that the total of the contents of these coarse precipitate forming elements be 0.0005% or more.

[0173] On the other hand, if the total of the contents of these elements exceeds 0.0100%, the total amount of the sulfides or the sulfides and oxides is excessive, and this hinders the growth of the grains in the strain-induced grain growth. Therefore, the total of the contents of the coarse precipitate forming elements is set to 0.0100% or less.

[0174] (B: 0.0000% to 0.0050%)

[0175] B is effective for the improvement of the texture in a small amount. Therefore, B can be contained. In the case where the above effect is obtained, it is preferable that the B content be 0.0001% or more.

[0176] On the other hand, if the B content is higher than 0.0050%, compounds of B hinder the grain growth at the time of annealing, the crystal grain diameter becomes fine, and this becomes a cause of an increase in iron loss. Therefore, the B content is set to 0.0050% or less.

[0177] (O: 0.0000% to 0.0200%)

[0178] O combines with Cr in the steel to form Cr2O3. This Cr2O3 contributes to the improvement of texture. Therefore, it can be contained. In the case where the above effects are obtained, it is preferable to set the O content to 0.0010% or more.

[0179] On the other hand, if the O content exceeds 0.0200%, Cr2O3 hinders the grain growth at the time of annealing, the crystal grain diameter becomes fine, and this becomes a cause of an increase in iron loss. Therefore, the O content is set to 0.0200% or less.

[0180] Next, the sheet thickness of the non-oriented electromagnetic steel sheet of the present embodiment is described. The thickness (sheet thickness) of the non-oriented electromagnetic steel sheet of the present embodiment is preferably 0.10 mm to 0.50 mm. When the thickness is higher than 0.50 mm, sometimes excellent iron loss cannot be obtained. Therefore, the thickness is preferably set to 0.50 mm or less. When the thickness is less than 0.10 mm, there is a case where the influence of leakage of magnetic flux from the surface of the non-oriented electromagnetic steel sheet and the like becomes large, and the magnetic characteristics become poor. In addition, when the thickness is less than 0.10 mm, it is difficult to pass the sheet in the annealing line, the number of non-oriented electromagnetic steel sheets of a certain size increases, and there is a possibility that the productivity decreases with an increase in the number of processes and the manufacturing cost increases. Therefore, the thickness is preferably set to 0.10 mm or more. More preferably, the thickness is 0.20 mm to 0.35 mm.

[0181] Next, the metallographic structure of the non-oriented electromagnetic steel sheet of the present embodiment is described. Hereinafter, the metallographic structure of the non-oriented electromagnetic steel sheet after skin pass rolling, the metallographic structure of the non-oriented electromagnetic steel sheet after the first heat treatment, and the metallographic structure of the non-oriented electromagnetic steel sheet after the second heat treatment are described.

[0182] First, the determined metallographic structure and the method for determining the same are described. The metallographic structure determined in the present embodiment is determined in a cross section parallel to the sheet surface of the steel sheet, by the following process.

[0183] First, polishing is performed in a manner that the sheet thickness center surface is exposed, and the polished surface (a surface parallel to the steel sheet surface) is subjected to EBSD (Electron Back Scattering Diffraction) for 2500 μm 2The above area is observed. The observation is performed on a total area of 2500 μm 2 The above, several places can be divided into several small areas. The step interval at the time of measurement is preferably 50 to 100 nm. From the observation data of EBSD, by a usual method, the following kinds of area, KAM (Kernel Average Misorientation) value and average crystal grain diameter are obtained.

[0184] S tot : Total area (observation area)

[0185] S tyl : Total area of oriented grains whose Taylor factor M according to the following (2) formula exceeds 2.8

[0186] S tra : Total area of oriented grains whose Taylor factor M according to the following (2) formula is 2.8 or less

[0187] S 100 : Total area of {100} oriented grains

[0188] S 110 : Total area of {110} oriented grains

[0189] K tyl : Average KAM value of oriented grains whose Taylor factor M according to the following (2) formula exceeds 2.8

[0190] K tra : Average KAM value of oriented grains whose Taylor factor M according to the following (2) formula is 2.8 or less

[0191] K 100 : Average KAM value of {100} oriented grains

[0192] K 110 : Average KAM value of {110} oriented grains

[0193] d ave : Average crystal grain diameter of the observation area

[0194] d 100 : Average crystal grain diameter of {100} oriented grains

[0195] d tyl : Average crystal grain diameter of oriented grains whose Taylor factor M according to the following (2) formula exceeds 2.8

[0196] d tra : Average crystal grain diameter of oriented grains whose Taylor factor M according to the following (2) formula is 2.8 or less

[0197] Here, the orientation margin of the crystal grains was set to 15°. In addition, when oriented crystal grains appeared below, the orientation margin was also set to 15°.

[0198] Here, the Taylor factor M is based on the following formula (2).

[0199]

[0200] The angle between the stress vector and the sliding direction vector of the crystal

[0201] λ: The angle between the stress vector and the normal vector of the crystal's sliding surface

[0202] The Taylor factor M described above assumes that the sliding deformation of the crystal occurs with the sliding plane {110} and the sliding direction <111>, and is the Taylor factor when compressive deformation in the plate thickness direction occurs within the in-plane strain in a plane parallel to the plate thickness direction and the rolling direction. Hereinafter, unless otherwise specified, the Taylor factor calculated for all crystallographically equivalent crystals according to formula (2) will be referred to simply as the "Taylor factor."

[0203] Next, in the following first to third embodiments, characteristics are defined by the above-mentioned area, KAM value, and average crystal grain size.

[0204] (Implementation 1)

[0205] First, the metallographic structure of a non-oriented electrical steel sheet after skin-pass rolling will be described. This metallographic structure accumulates sufficient strain to induce strain-induced grain growth, and can be positioned in the initial stage before strain-induced grain growth occurs. The characteristics of the metallographic structure of a steel sheet after skin-pass rolling are generally determined by the conditions related to the development of target grain orientation and the sufficient strain accumulated to induce strain-induced grain growth.

[0206] In the non-oriented electrical steel sheet of the present embodiment, the area of ​​predetermined oriented grains satisfies the following formulas (3) to (5).

[0207] 0.20≦S tyl / S tot ≦0.85···(3)

[0208] 0.05≦S 100 / S tot ≦0.80···(4)

[0209] S 100 / S tra ≧0.50···(5)

[0210] S tylThe number of orientations with a sufficiently large Taylor factor. During strain-induced grain growth, orientations with a small Taylor factor and little accumulation of strain due to processing will preferentially grow while eroding orientations with a large Taylor factor and accumulated strain due to processing. Therefore, in order to develop special orientations through strain-induced grain growth, S tyl In this embodiment, the area ratio S relative to the total area is tyl / S tot In this embodiment, the area ratio S tyl / S tot Set to 0.20 or more. Area ratio S tyl / S tot When the area ratio S is less than 0.20, the target crystal orientation will not be sufficiently developed by strain-induced grain growth. tyl / S tot It is 0.30 or more, more preferably 0.50 or more.

[0211] Area ratio S tyl / S tot The upper limit of is related to the amount of crystal orientation grains that should be developed in the process of strain-induced grain growth as described below, but this condition is not simply determined by the ratio of the orientation that grows preferentially to the orientation that is eroded. First, as described later, the area ratio S of the {100} oriented grains that should be developed in strain-induced grain growth is 100 / S tot is 0.05 or more, so the area ratio S tyl / S tot Is less than 0.95. However, if the area ratio S tyl / S tot If the amount of is too much, the preferential growth of {100} oriented grains will not occur due to the relationship with the strain described later. The relationship with the strain amount will be described in detail later, but in this embodiment, the area ratio S tyl / S tot Preferably, the area ratio S tyl / S tot It is 0.75 or less, more preferably 0.70 or less.

[0212] In the subsequent strain-induced grain growth process, {100} oriented grains are preferentially grown. {100} orientation is one of the orientations in which the Taylor factor is sufficiently small and strain caused by processing is difficult to accumulate. It is an orientation that can be preferentially grown in the strain-induced grain growth process. In this embodiment, the presence of {100} oriented grains is necessary. In this embodiment, the area ratio of {100} oriented grains to S is set to 1. 100 / S totSet to 0.05 or more. If the area ratio S of the {100} oriented grains 100 / S tot If the area ratio S is less than 0.05, the {100} oriented grains will not be sufficiently developed through subsequent strain-induced grain growth. 100 / S tot It is 0.10 or more, and more preferably 0.20 or more.

[0213] Area ratio S 100 / S tot The upper limit of is determined by the amount of crystal grains with a crystal orientation that should be eroded in the strain-induced grain growth. In this embodiment, the area ratio S of the orientation with a Taylor factor exceeding 2.8 that should be eroded in the strain-induced grain growth is tyl / S tot is 0.20 or more, so that the area ratio S 100 / S tot The area ratio S is preferably less than 0.80. Among them, the effect is significant when the amount of {100} oriented grains before strain-induced grain growth is low, and the {100} oriented grains can be more developed. 100 / S tot It is 0.60 or less, more preferably 0.50 or less, and even more preferably 0.40 or less.

[0214] While the explanation focuses on {100}-oriented grains as the oriented grains that should be preferentially grown, similarly to {100}-oriented grains, there are many other oriented grains that have sufficiently small Taylor factors and are less susceptible to accumulation of strain due to processing, that is, those that can preferentially grow during strain-induced grain growth. Such oriented grains compete with the {100}-oriented grains that should be preferentially grown. On the other hand, these oriented grains do not have as many easy magnetization axis directions (<100> directions) within the steel sheet as {100}-oriented grains. Therefore, if these orientations develop during strain-induced grain growth, the magnetic properties deteriorate, making it inappropriate. Therefore, in this embodiment, it is stipulated that the proportion of {100}-oriented grains among the orientations with sufficiently small Taylor factors and less susceptible to accumulation of strain due to processing is ensured.

[0215] In the present invention, the area including the oriented grains with a Taylor factor of 2.8 or less, which are considered to compete with the {100} oriented grains in the strain-induced grain growth, is defined as S. tra Moreover, as shown in formula (5), the area ratio S 100 / S tra Setting it to 0.50 or more ensures the priority of {100} oriented grain growth. 100 / S traless than 0.50, the {100} oriented grains cannot be sufficiently developed by strain-induced grain growth. Preferably, the area ratio S 100 / S tra is 0.80 or more, more preferably 0.90 or more. On the other hand, the upper limit of the area ratio S 100 / S tra is not particularly limited, and the oriented grains having a Taylor factor of 2.8 or less can also be all {100} oriented grains (i.e., S 100 / S tra = 1.00).

[0216] Further, in the present embodiment, a relationship with {110} oriented grains, which are known as orientations that easily grow in strain-induced grain growth, is particularly specified. The {110} orientation is an orientation that is relatively easily developed in a common method of increasing the crystal grain size in a hot-rolled steel sheet and recrystallizing it in cold rolling, or recrystallizing it by cold rolling at a relatively low rolling rate, and the like, and is particularly considered in competition with {100} oriented grains that should be preferentially grown. If the {110} oriented grains are developed in strain-induced grain growth, the in-plane anisotropy of the steel sheet becomes very large, which is inappropriate. Therefore, in the present embodiment, it is preferable to control the area ratio S 100 / S 110 of the {100} oriented grains and the {110} oriented grains in such a manner as to satisfy the (8) formula, and to ensure the priority of growth of the {100} oriented grains.

[0217] S 100 / S 110 ≧ 1.00 (8)

[0218] In order to more reliably avoid the {110} oriented grains from unexpectedly being developed due to strain-induced grain growth, the area ratio S 100 / S 110 of the {100} oriented grains and the {110} oriented grains is preferably 1.00 or more. More preferably, the area ratio S 100 / S 110 of the {100} oriented grains and the {110} oriented grains is 2.00 or more, and even more preferably 4.00 or more. The upper limit of the area ratio S 100 / S 110 of the {100} oriented grains and the {110} oriented grains is not particularly limited, and the area rate of the {110} oriented grains can also be zero. That is, even if the area ratio S 100 / S 110 of the {100} oriented grains and the {110} oriented grains is infinite, the (8) formula holds.

[0219] The present embodiment can achieve more excellent magnetic properties by combining the crystal orientation described above and the strain described below. In the present embodiment, as a specification related to strain, the following (6) formula needs to be satisfied.

[0220] K 100 / K tyl ≦0.990···(6)

[0221] The requirements related to strain are defined by formula (6). Formula (6) is the ratio of the strain accumulated by {100} oriented grains (average KAM value) to the strain accumulated by oriented grains with a Taylor factor greater than 2.8 (average KAM value). Here, KAM is the orientation difference between adjacent measurement points within the same grain, and the KAM value increases at locations with greater strain. From a crystallographic point of view, for example, when compressive deformation in the thickness direction is performed under a plane strain state in a plane parallel to the thickness direction and the rolling direction, that is, when the steel plate is simply rolled, K is usually 100 With K tyl Ratio K 100 / K tyl Less than 1. However, in reality, the strain corresponding to the crystal orientation observed microscopically is diverse due to the influence of restrictions caused by adjacent grains, precipitates present in the grains, and further macroscopic deformation changes caused by contact with tools (rolling rolls, etc.) during deformation. Therefore, it is difficult to show the influence of the purely geometric orientation caused by the Taylor factor. In addition, for example, even for grains with the same orientation, very large changes will be formed due to the particle size, particle morphology, orientation or particle size of adjacent grains, state of precipitates, position in the thickness direction, etc. Furthermore, even in one grain, the strain distribution varies greatly due to the formation of deformation bands near the grain boundary and within the grain.

[0222] Taking such changes into consideration, in order to obtain excellent magnetic properties, in this embodiment, K 100 / K tyl Set to 0.990 or less. 100 / K tyl If the K value is higher than 0.990, the specificity of the region to be eroded is lost. Therefore, it is difficult to induce strain-induced grain growth. 100 / K tyl It is 0.970 or less, more preferably 0.950 or less.

[0223] In the competition with {100} oriented grains that should be preferentially grown, the relationship with oriented grains having a Taylor factor of 2.8 or less preferably satisfies the formula (7).

[0224] K 100 / K tra <1.010···(7)

[0225] In order to preferentially grow {100} oriented grains, it is preferred to 100 / K tra Set to be less than 1.010. 100 / Ktra It is an indicator related to the competition between orientations where strain is difficult to accumulate and there is a possibility of preferential growth. If K 100 / K tra If K is greater than 1.010, the priority of the {100} orientation in strain-induced grain growth cannot be exerted, and the target crystal orientation will not develop. 100 / K tra It is more preferably 0.970 or less, and even more preferably 0.950 or less.

[0226] In the competition with the {100} oriented grains that should be preferentially grown, the relationship with the {110} oriented grains is preferably considered in terms of strain, as well as the area. In this relationship, the ratio K of the average KAM values ​​of the {100} oriented grains to the {110} oriented grains is 100 / K 110 It is preferable to control so as to satisfy the formula (9) and to ensure the priority of {100} oriented grain growth.

[0227] K 100 / K 110 <1.010···(9)

[0228] In order to more reliably avoid the accidental development of {110} oriented grains due to strain-induced grain growth, K 100 / K 110 is less than 1.010. K 100 / K 110 It is more preferably 0.970 or less, and even more preferably 0.950 or less.

[0229] In formula (9), when there are no crystal grains having an orientation corresponding to the denominator, this formula is not evaluated based on numerical values, and it is considered that this formula is satisfied.

[0230] In the metallographic structure of the non-oriented electrical steel sheet after skin-pass rolling of this embodiment, there are no particular restrictions on the grain size. This is because, when appropriate strain-induced grain growth is induced by the subsequent first heat treatment, the relationship with the grain size is not that strong. In other words, whether the targeted appropriate strain-induced grain growth is induced can be largely determined by the relationship between the amount (area) of each crystal orientation and the relationship between the deformation amounts of each orientation, in addition to the chemical composition of the steel sheet.

[0231] However, if the crystal grain size is very coarse, although strain will be induced, sufficient grain growth in the practical temperature range is difficult to occur. In addition, if the crystal grain size is very coarse, it is difficult to avoid the degradation of magnetic properties. Therefore, the practical average crystal grain size is preferably set to 300 μm or less. More preferably, it is 100 μm or less, more preferably 50 μm or less, and particularly preferably 30 μm or less. The finer the crystal grain size, the easier it is to identify the development of the target crystal orientation caused by strain-induced grain growth when the distribution of crystal orientation and strain is properly controlled. However, if it becomes very fine, it is difficult to form a difference in the amount of strain for each crystal orientation due to the constraints with adjacent grains in the processing of applying strain as described above. From this point of view, the average crystal grain size is preferably 3 μm or more, more preferably 8 μm or more, and more preferably 15 μm or more.

[0232] (Implementation Method 2)

[0233] Next, the metallographic structure of the non-oriented electrical steel sheet after skin-pass rolling, after strain-induced grain growth (and before the completion of strain-induced grain growth) is described. The non-oriented electrical steel sheet of this embodiment releases at least a portion of the strain through strain-induced grain growth. The characteristics of the metallographic structure of the steel sheet after strain-induced grain growth are determined by crystal orientation, strain, and grain size.

[0234] In the non-oriented electrical steel sheet of this embodiment, the area of ​​the specified oriented grains satisfies the following equations (10) to (12). These specifications differ from the numerical ranges of equations (3) to (5) for the skin-pass rolled non-oriented electrical steel sheet described above. This is because {100}-oriented grains grow preferentially during strain-induced grain growth, increasing their area, while oriented grains with a Taylor factor exceeding 2.8 are primarily eroded by {100}-oriented grains, decreasing their area.

[0235] S tyl / S tot ≦0.70···(10)

[0236] 0.20≦S 100 / S tot ···(11)

[0237] S 100 / S tra ≧0.55···(12)

[0238] Area ratio S tyl / S tot The upper limit of is determined as one of the parameters indicating the extent of strain-induced grain growth. tyl / S totWhen the area ratio S is greater than 0.70, it means that the grains of the oriented grains with a Taylor factor exceeding 2.8 are not sufficiently eroded, and strain-induced grain growth is not sufficiently induced. In other words, the {100} oriented grains that should be developed are not sufficiently developed, and thus the magnetic properties are not sufficiently improved. Therefore, in this embodiment, the area ratio S is set to tyl / S tot Preferably, the area ratio S tyl / S tot The area ratio S is 0.60 or less, more preferably 0.50 or less. tyl / S tot A smaller value is preferred, and therefore, there is no need to define a lower limit, and it may be 0.00.

[0239] In addition, in this embodiment, the area ratio S 100 / S tot Set to 0.20 or more. Area ratio S 100 / S tot The lower limit of is determined as one of the parameters indicating the extent of strain-induced grain growth, and the area ratio S 100 / S tot When the area ratio S is less than 0.20, the development of {100} oriented grains is insufficient, and thus the magnetic properties are not sufficiently improved. 100 / S tot The area ratio S is 0.40 or more, more preferably 0.60 or more. 100 / S tot A higher value is preferred, and therefore, there is no need to define an upper limit, and it may be 1.00.

[0240] As in the first embodiment, the relationship between the {100}-oriented grains and the {100}-oriented grains that are thought to compete with the {100}-oriented grains in strain-induced grain growth is also important. 100 / S tra When it is larger, the priority of {100} oriented grain growth is ensured, and the magnetic properties are good. 100 / S tra Less than 0.55 indicates that {100} oriented grains have not developed sufficiently through strain-induced grain growth, and oriented grains with Taylor factors exceeding 2.8 are being eroded by oriented grains with smaller Taylor factors other than {100} oriented grains. In this case, the in-plane anisotropy of the magnetic properties also increases. Therefore, in this embodiment, the area ratio S is set to 100 / S tra It is preferably set to 0.55 or more. 100 / S tra On the other hand, the area ratio S does not need to be particularly limited. 100 / S traThe upper limit of the area ratio S

[0241] In the present embodiment, the relationship with the {110} oriented grains is also prescribed as in Embodiment 1. In the present embodiment, the area ratio S 100 / S 110 The priority of growth of the {100} oriented grains is ensured by satisfying the following (18) formula.

[0242] S 100 / S 110 ≧1.00···(18)

[0243] As shown in the (18) formula, in the present embodiment, the area ratio S 100 / S 110 is preferably 1.00 or more. When the {110} oriented grains develop in the strain-induced grain growth, the area ratio S 100 / S 110 of less than 1.00, the anisotropy in the steel sheet plane becomes very large, and it easily becomes a defect in characteristics. More preferably, the area ratio S 100 / S 110 is 2.00 or more, and still more preferably 4.00 or more. The upper limit of the area ratio S 100 / S 110 does not need to be particularly limited, and the area ratio of the {110} oriented grains can also be zero. That is, even if the area ratio S 100 / S 110 diverges infinitely, the (18) formula is satisfied.

[0244] Next, the prescription related to the strain to be satisfied in the present embodiment is described. The strain amount of the non-oriented electromagnetic steel sheet of the present embodiment is greatly reduced compared to the strain amount in the state after the skin pass rolling described in Embodiment 1, and becomes a state in which each crystal orientation has a characteristic strain amount.

[0245] The prescription related to the strain in the present embodiment is different in the numerical range compared to the aforementioned (6) formula for the steel sheet after the skin pass rolling, and satisfies the following (13) formula.

[0246] K 100 / K tyl ≦1.010···(13)

[0247] If the strain-induced grain growth sufficiently proceeds, a state in which most of the strain of the steel sheet is released, the strain of each crystal orientation is homogenized, and the variation in the strain is sufficiently small, the ratio shown in the (13) formula becomes a value close to 1.

[0248] On the basis of considering such a change, in the present embodiment, in order to obtain excellent magnetic properties, K 100 / K tyl is set to 1.010 or less. K 100 / K tyl If K is higher than 1.010, the release of strain is insufficient, and thus the reduction of iron loss is insufficient, in particular. Preferably, K 100 / K tyl is 0.990 or less, and more preferably 0.970 or less. Even if the non-oriented electromagnetic steel sheet of the present embodiment is a steel sheet obtained by performing the first heat treatment on a steel sheet satisfying the aforementioned (6), the value of (13) exceeds 1.000 due to errors in measurement or the like.

[0249] In competition with the {100} oriented grains which should be preferentially grown, with respect to the oriented grains having a Taylor factor of 2.8 or less, it is preferable to satisfy (16).

[0250] K 100 / K tra < 1.010 (16)

[0251] In order to make the {100} oriented grains preferentially grow, it is preferable to set K 100 / K tra to less than 1.010. If this K 100 / K tra is 1.010 or more, the release of strain is insufficient, and the reduction of iron loss is insufficient, in particular. The first heat treatment is performed on the non-oriented electromagnetic steel sheet satisfying the aforementioned (7), and thus a non-oriented electromagnetic steel sheet satisfying (16) is obtained.

[0252] In Embodiment 1, it is explained that it is preferable to consider the relationship with the strain of the {110} oriented grains. On the other hand, in the present embodiment, the condition in which the strain of the steel sheet is released in a large part is made to be sufficient for strain-induced grain growth. Thus, the value of K 110 which corresponds to the strain accumulated by the {110} oriented grains becomes the same degree as the value of K 100 in which the strain is released. As with (9), it is preferable to satisfy (19).

[0253] K 100 / K 110 < 1.010 (19)

[0254] That is, as with (9), it is preferable that K 100 / K 110 be less than 1.010. This K 100 / K 110When the value is 1.010 or more, there is a case where the release of strain is insufficient and the decrease in iron loss is insufficient, in particular. By subjecting the non-oriented electromagnetic steel sheet satisfying the aforementioned (9) to the first heat treatment, a non-oriented electromagnetic steel sheet satisfying (19) is obtained.

[0255] In (13) and (19), in the case where there is no crystal grain having an orientation corresponding to the denominator, the evaluation based on the value is not performed with respect to the formula, and it is considered that the formula is satisfied.

[0256] Next, the regulation related to the crystal grain diameter that should be satisfied in the present embodiment is described. In the metallographic structure in the case where strain-induced grain growth is sufficiently performed and most of the strain is released, the crystal grain diameter of each crystal orientation has a large influence on the magnetic characteristics. The crystal grains of the orientation that is preferentially grown by the strain-induced grain growth become coarse, and the crystal grains of the orientation that is eaten away by this become fine. In the present embodiment, the relationship of the average crystal grain diameter satisfies (14) and (15).

[0257] d 100 / d ave > 1.00 (14)

[0258] d 100 / d tyl > 1.00 (15)

[0259] These formulas indicate that the average crystal grain diameter d 100 of the preferentially grown orientation, that is, the {100} orientation crystal grains, is relatively large. These ratios in (14) and (15) are preferably 1.30 or more, more preferably 1.50 or more, and still more preferably 2.00 or more. The upper limit of these ratios is not particularly limited, but although the crystal grains of the eaten-away orientation grow slower than the {100} orientation crystal grains, the crystal grains grow in the first heat treatment, and thus the above ratios do not easily become excessively large, and the practical upper limit is about 10.00.

[0260] Further, in the present embodiment, it is preferable that (17) be satisfied.

[0261] d 100 / d tra > 1.00 (17)

[0262] This formula indicates that the average crystal grain diameter d 100The ratio in the formula (15) is preferably 1.30 or more, more preferably 1.50 or more, and particularly preferably 2.00 or more. The upper limit of the ratio is not particularly limited, but the grains of the {100} orientation grow while the grains of the {100} orientation are also grown in the first heat treatment, although the grains of the {100} orientation grow slower than the grains of the {100} orientation. Therefore, the ratio is not easily made excessively large, and the upper limit of practicality is about 10.00.

[0263] In addition, the range of the average crystal grain diameter is not particularly limited, but if the average crystal grain diameter is excessively large, it is difficult to avoid the deterioration of magnetic properties. Therefore, the average crystal grain diameter of the relatively large grains, i.e., the grains of the {100} orientation, is preferably set to 500 μm or less in the present embodiment. More preferably, the average crystal grain diameter of the grains of the {100} orientation is 400 μm or less, more preferably 300 μm or less, and particularly preferably 200 μm or less. On the other hand, if a state in which sufficient growth of the {100} orientation is ensured is assumed, the average crystal grain diameter of the grains of the {100} orientation is preferably 40 μm or more, more preferably 60 μm or more, and particularly preferably 80 μm or more.

[0264] In the formula (15), in the case where there is no grain having an orientation corresponding to the denominator, the formula is satisfied without evaluation based on the value.

[0265] (Embodiment 3)

[0266] In the above-described embodiments 1 and 2, the strain of the steel sheet is determined by the KAM value, and thus the characteristics of the steel sheet are defined. In the present embodiment, the steel sheet described in the embodiment 1 or 2 is sufficiently annealed for a long time, and the steel sheet after the grain growth is further defined. In such a steel sheet, the strain-induced grain growth is substantially completed, and as a result, the strain is substantially completely released, and thus the characteristics are very preferable. That is, the grains of the {100} orientation are grown by the strain-induced grain growth, and further, the steel sheet after the normal grain growth in the second heat treatment becomes a steel sheet in which the aggregation to the {100} orientation is stronger. In the present embodiment, the crystal orientation and the crystal grain diameter of the steel sheet obtained by performing the second heat treatment on the steel sheet described in the embodiment 1 or 2 (i.e., the non-oriented electromagnetic steel sheet after the skin pass rolling, the non-oriented electromagnetic steel sheet on which the second heat treatment is performed after the first heat treatment, or the non-oriented electromagnetic steel sheet on which the second heat treatment is performed without the first heat treatment) are described.

[0267] The steel sheet (non-oriented electromagnetic steel sheet) obtained by the second heat treatment satisfies the following (20) to (22) with respect to the area of each oriented grain. These provisions differ in numerical range from the aforementioned (3) to (5) with respect to the skin-passed steel sheet and (10) to (12) with respect to the steel sheet after strain-induced grain growth based on the first heat treatment. With the strain-induced grain growth and the second heat treatment thereafter, the {100}-oriented grains further grow, the area thereof increases, and the oriented grains having a Taylor factor exceeding 2.8 are mainly encroached upon by the {100}-oriented grains, the area thereof further decreases.

[0268] S tyl / S tot <0.55···(20)

[0269] S 100 / S tot >0.30···(21)

[0270] S 100 / S tra ≧0.60···(22)

[0271] In the present embodiment, the area ratio S tyl / S tot is set to be less than 0.55. The total area S tyl may be zero. The upper limit of the area ratio S tyl / S tot is determined as one of parameters indicating the degree of progress of the growth of the {100}-oriented grains. The area ratio S tyl / S tot of 0.55 or more indicates that the oriented grains having a Taylor factor exceeding 2.8 to be encroached upon at the stage of the strain-induced grain growth are not sufficiently encroached upon. At this time, the magnetic properties cannot be sufficiently improved. Preferably, the area ratio S tyl / S tot is 0.40 or less, more preferably 0.30 or less. The area ratio S tyl / S tot is more preferably smaller, and thus the lower limit is not specified and can be 0.00.

[0272] Further, in the present embodiment, the area ratio S 100 / S tot is set to exceed 0.30. The area ratio S 100 / S tot of 0.30 or less does not sufficiently improve the magnetic properties. Preferably, the area ratio S 100 / S tot is 0.40 or more, more preferably 0.50 or more. The area ratio S 100 / S totWhen the value is 1.00, the crystal structure is entirely composed of {100} oriented grains, and no grains with other orientations exist. This embodiment also applies to this situation.

[0273] As in the first and second embodiments, the relationship between the {100} oriented grains and the {100} oriented grains that are thought to compete with the {100} oriented grains in the strain induced grain growth is also important. 100 / S tra When the area ratio S is sufficiently large, the priority of {100} oriented grain growth is ensured even in the normal grain growth state after strain-induced grain growth, and the magnetic properties are good. 100 / S tra When the ratio is less than 0.60, {100} oriented grains will not be fully developed by strain induced grain growth, and in the normal grain growth state after strain induced grain growth, oriented grains with small Taylor factors other than {100} oriented grains will grow to a considerable extent, and the in-plane anisotropy of magnetic properties will also increase. Therefore, in this embodiment, the area ratio S is set to 100 / S tra Preferably, the area ratio S 100 / S tra is 0.70 or more, more preferably 0.80 or more. 100 / S tra The upper limit of does not need to be particularly limited, and all oriented grains with a Taylor factor of 2.8 or less may be {100} oriented grains.

[0274] In a metallographic structure where strain-induced grain growth and subsequent normal grain growth have fully progressed and the strain in the steel plate has been largely released, the grain size of each crystal orientation has a significant impact on the magnetic properties. The {100}-oriented grains that preferentially grow during strain-induced grain growth also become coarse grains after normal grain growth. In this embodiment, the relationship between the average grain sizes satisfies equations (23) and (24).

[0275] d 100 / d ave ≧0.95···(23)

[0276] d 100 / d tyl ≧0.95···(24)

[0277] These formulas represent the average crystal grain size d of {100} oriented grains. 100It is 0.95 times or more of the average crystal grain size of other grains. These ratios in formula (23) and formula (24) are preferably 1.00 or more, more preferably 1.10 or more, and even more preferably 1.20 or more. The upper limits of these ratios are not particularly limited, but in normal grain growth, grains other than {100} oriented grains also grow, but at the moment of entering normal grain growth, that is, at the moment when strain-induced grain growth ends, {100} oriented grains become coarse and have the so-called size advantage. It is advantageous that {100} oriented grains also coarsen during normal grain growth, so the above ratios maintain a sufficiently characteristic range. Therefore, the practical upper limit is about 10.00. If any of these ratios exceeds 10.00, mixed grains are formed, and problems related to processing such as punchability sometimes occur.

[0278] Furthermore, in the relationship of the average crystal grain size, it is preferable that the following formula (25) is also satisfied.

[0279] d 100 / d tra ≧0.95···(25)

[0280] This formula represents the average crystal grain size d of the preferentially grown {100} oriented grains. 100 Relatively large. The ratio in formula (25) is preferably greater than 1.00, more preferably greater than 1.10, and particularly preferably greater than 1.20. The upper limit of this ratio is not particularly limited, but grains other than the {100} oriented grains also grow during normal grain growth, but at the moment of entering normal grain growth, that is, at the moment when strain-induced grain growth is completed, the {100} oriented grains become coarse and have the so-called size advantage. It is advantageous that the {100} oriented grains also coarsen during normal grain growth, so the above ratio fully maintains the characteristic range. Therefore, the upper limit of practicality is about 10.00. When any of these ratios exceeds 10.00, mixed grains are formed, and problems related to processing such as punchability may occur.

[0281] In addition, the range of the average crystal grain size is not particularly limited, but if the average crystal grain size is too coarse, it is difficult to avoid the deterioration of the magnetic properties. Therefore, similarly to Embodiment 2, in this embodiment, the practical average crystal grain size of the relatively coarse grains, i.e., the {100} oriented grains, is preferably 500 μm or less. More preferably, the average crystal grain size of the {100} oriented grains is 400 μm or less, 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 {100} oriented grains, if it is assumed that sufficient preferential growth of the {100} orientation is ensured, is preferably 40 μm or more, more preferably 60 μm or more, and even more preferably 80 μm or more.

[0282] In the formula (24), in the absence of a crystal grain having an orientation equivalent to the denominator, no numerical-based evaluation is performed for the formula, and it is considered that the formula is satisfied.

[0283] [Properties]

[0284] The non-oriented electromagnetic steel sheet of the present embodiment controls the chemical components and the microstructure as described above, and thus can obtain excellent magnetic properties (low iron loss) even after shearing.

[0285] Further, in consideration of application to a motor, it is preferable that the anisotropy of the iron loss be small. Therefore, it is preferable that the ratio of W15 / 50 in the C direction (width direction) to W15 / 50 in the L direction (rolling direction), that is, W15 / 50(C) / W15 / 50(L), be less than 1.3.

[0286] The magnetic measurement can be performed by the measurement method described in JIS C 2550-1 (2011) and JIS C 2550-3 (2019), or by the measurement method described in JIS C 2556 (2015). Further, in the case where the sample is small and the measurement described in the above JIS cannot be performed, the electromagnetic loop can be measured using a device that can measure a test piece of 55 mm square or a smaller test piece based on JIS C 2556 (2015).

[0287] [Manufacturing method]

[0288] Next, the manufacturing method of the non-oriented electromagnetic steel sheet of the present embodiment will be described. The non-oriented electromagnetic steel sheet of the present embodiment is obtained by a manufacturing process including a hot rolling step, a hot rolled sheet annealing step, a cold rolling step, an intermediate annealing step, and a skin pass rolling step.

[0289] Further, the other non-oriented electromagnetic steel sheet of the present embodiment is obtained by a manufacturing process including a hot rolling step, a hot rolled sheet annealing step, a cold rolling step, an intermediate annealing step, a skin pass rolling step, and a first heat treatment.

[0290] Further, the other non-oriented electromagnetic steel sheet of the present embodiment is obtained by a manufacturing process including a hot rolling step, a hot rolled sheet annealing step, a cold rolling step, an intermediate annealing step, a skin pass rolling step, a first heat treatment step performed as necessary, and a second heat treatment step.

[0291] [Hot rolling step]

[0292] First, a steel material having the above chemical components is heated, and hot rolling is performed. The steel material is, for example, a billet manufactured by a general continuous casting. For example, the hot-rolled billet is heated at a temperature of about 1150°C (1,100 to 1,200°C), the finish rolling temperature is set to about 850°C (750 to 950°C), and the coiling temperature is set to about 600°C (500 to 700°C).

[0293] [Annealing process of hot-rolled sheet]

[0294] Subsequently, the hot-rolled steel sheet (hot-rolled sheet) is subjected to hot-rolled sheet annealing, for example, at a temperature of 1,000 to 1,100°C for 1 to 100 seconds. If the hot-rolled sheet annealing temperature is 1,000°C or lower, {111} oriented grains are more likely to be generated than {100} oriented grains, and it is difficult to obtain a preferred texture.

[0295] [Cold rolling process]

[0296] Next, the hot-rolled sheet is subjected to pickling and cold rolling. In the cold rolling, the reduction is preferably set to 90 to 95%. If the reduction is less than 90%, {111} oriented grains having poor magnetic properties increase at the time of recrystallization.

[0297] [Intermediate annealing process]

[0298] The cold-rolled steel sheet (cold-rolled sheet) is subjected to intermediate annealing. In the present embodiment, for example, the intermediate annealing is performed at a temperature of 700 to 900°C for 1 to 100 seconds. If the crystal grain diameter before the cold rolling is 200 μm or more and the cold rolling is performed at a reduction of 90%, {100} oriented grains in the rolled structure preferentially recrystallize. If the temperature of the intermediate annealing is too low, recrystallization does not occur, {100} oriented grains do not sufficiently grow, and there is a case where the magnetic flux density does not increase. Further, if the temperature of the intermediate annealing is higher than 900°C, the grains become too large, and it is difficult to grow at the time of subsequent skin pass rolling and strain-induced grain growth, and it is difficult to grow {100} oriented grains. Therefore, the temperature of the intermediate annealing is preferably set to 700 to 900°C.

[0299] [Skin pass rolling process]

[0300] The steel sheet after the intermediate annealing is subjected to skin pass rolling. As described above, if the rolling is performed in a state where {100} grains are more, the {100} grains further grow. The reduction of the skin pass rolling is preferably set to 5 to 25%.

[0301] In the non-oriented electromagnetic steel sheet, in a case where the strain distribution described above is present, when the reduction of the cold rolling (%) is set to Rm and the reduction (%) at the time of the skin pass rolling is set to Rs, the reduction of the cold rolling and the skin pass rolling is preferably adjusted so as to satisfy 90 < Rm < 95 and 5 < Rs < 20.

[0302] [First heat treatment step]

[0303] Next, first heat treatment for promoting strain-induced grain growth is performed. The first heat treatment is preferably performed at 700 to 950°C for 1 second to 100 seconds.

[0304] When the heat treatment temperature is less than 700°C, strain-induced grain growth does not occur. Further, when it is higher than 950°C, not only strain-induced grain growth but also normal grain growth occurs, and the above-described metallographic structure of Embodiment 2 cannot be obtained.

[0305] Further, when the heat treatment time (holding time) exceeds 100 seconds, the production efficiency is significantly reduced, and it is not practical. The holding time is set to less than 1 second, and it is not easy in industry, and therefore the holding time is set to 1 second or more.

[0306] [Second heat treatment step]

[0307] The second heat treatment is preferably performed at 1 second to 100 seconds when the temperature range of 950 to 1050°C is set, or more than 1000 seconds when the temperature range of 700 to 900°C is set. The second heat treatment can be performed on the steel sheet after the skin pass rolling step in which the first heat treatment is omitted, or on the steel sheet after the first heat treatment step.

[0308] By performing heat treatment in the above-described temperature range and time, when the first heat treatment is omitted, strain-induced grain growth is performed after normal grain growth, and depending on the conditions of the first heat treatment, strain-induced grain growth is sometimes performed in the second heat treatment thereafter.

[0309] As described above, the non-oriented electromagnetic steel sheet of the present embodiment can be manufactured. However, the manufacturing method is one example of the method of manufacturing the non-oriented electromagnetic steel sheet of the present embodiment, and the manufacturing method is not limited.

[0310] Embodiment

[0311] Next, with respect to the non-oriented electromagnetic steel sheet of the present application, an embodiment is shown while being specifically described. The embodiment shown below is only one example of the non-oriented electromagnetic steel sheet of the present application, and the non-oriented electromagnetic steel sheet of the present application is not limited to the example described below.

[0312] (First Embodiment)

[0313] A steel ingot having the chemical components shown in Table 1A below was produced by casting molten steel. Here, (1) indicates the value on the left side of the aforementioned (1). Thereafter, the produced steel ingot was heated to 1150°C and hot-rolled to be rolled in a manner so as to have the sheet thickness shown in Table 1B. Also, after the finish rolling, water cooling was performed and the hot-rolled steel sheet was coiled. The temperature at the stage of the final pass of the finish rolling (final temperature) at this time was 830°C and the coiling temperature was in the range of 500 to 700°C.

[0314] Next, the hot-rolled steel sheet was subjected to hot-rolled sheet annealing for 30 seconds under the conditions shown in Table 1B, the scale was removed by pickling, and cold-rolling was performed at the reduction shown in Table 1B. Then, intermediate annealing was performed in a non-oxidizing atmosphere, and intermediate annealing was performed at 800°C for 30 seconds. Next, second cold-rolling (skin pass) was performed at the reduction shown in Table 1B. Although not shown in the table, the average crystal grain diameter after the skin pass was in the range of 25 to 30 μm.

[0315] Next, in order to investigate the texture, a portion of the steel sheet was cut, and the cut test piece was reduced in thickness to 1 / 2 thickness, and EBSD observation was performed on the processed surface (a surface parallel to the surface of the steel sheet) by the above-mentioned procedure (step interval: 100 nm). By the EBSD observation, the area and the average KAM value of the kind shown in Table 2 were obtained.

[0316] Further, as the second heat treatment, the steel sheet was subjected to annealing at 800°C for 2 hours. From the steel sheet after the second heat treatment, a 55 mm square test piece was taken as a measurement sample. The test sample was taken using a shearing machine. Then, the magnetic properties were measured according to JIS C2556 (2015) to measure the iron loss W10 / 400 (average value in the rolling direction and the width direction of the energy loss generated in the test piece when excited at the maximum magnetic flux density of 1.0 T and the frequency of 400 Hz), W15 / 50 (C) (value in the width direction of the energy loss generated in the test piece when excited at the maximum magnetic flux density of 1.5 T and the frequency of 50 Hz), and W15 / 50 (L) (value in the rolling direction of the energy loss generated in the test piece when excited at the maximum magnetic flux density of 1.5 T and the frequency of 50 Hz).

[0317] Further, W15 / 50 (C) was divided by W15 / 50 (L) to obtain W15 / 50 (C) / W15 / 50 (L).

[0318] The measurement results are shown in Table 2.

[0319] [Table 1A]

[0320]

[0321] [Table 1B]

[0322]

[0323] [Table 2]

[0324]

[0325] Underlined conditions in Tables 1A, 1B, and 2 denote conditions outside the scope of the present invention. Inventive Examples Nos. 101 to 107, 113 to 116, 118, 121, 122, 124 to 141, and 151 all have good values ​​for iron loss W10 / 400.

[0326] On the other hand, in No. 108 as a comparative example, the Mn concentration is high, and the value on the left side of the formula (1) is higher than 0.00 (the component of the α-γ phase transition). As a result, the area ratio S tyl / S tot and area ratio S 100 / S tot The values ​​are outside the ranges of equations (3) and (4), respectively. As a result, the iron loss W10 / 400 is high.

[0327] As comparative examples, No. 109 to No. 112, No. 117, No. 120, and No. 123 are not suitable for at least any one of the temperature in hot-rolled sheet annealing, the rolling reduction in cold rolling, and the rolling reduction in skin pass rolling. Therefore, any one of the equations (3) to (6) is not satisfied. As a result, the iron loss W10 / 400 is high.

[0328] In Comparative Example No. 119, the cold rolling reduction was too high, causing fracture, and the subsequent steps were not performed.

[0329] No. 142 to No. 150 have chemical compositions outside the range of the present invention and thus do not satisfy equations (3) to (4). Iron loss W10 / 400 increases, or fracture occurs during cold rolling.

[0330] (Second embodiment)

[0331] By casting molten steel, a steel ingot having the chemical composition shown in Table 3A is produced. Here, the left side of formula (1) represents the value of the left side of the aforementioned formula (1). Thereafter, the produced steel ingot is heated to 1150°C and hot rolled to form a plate thickness shown in Table 3B. Moreover, after the finish rolling is completed, water cooling is performed and the hot-rolled steel plate is coiled. At this time, the temperature of the final pass of the finish rolling (final temperature) is 830°C, and the coiling temperature is in the range of 500 to 700°C.

[0332] Next, the hot-rolled sheet was annealed for 30 seconds in a hot-rolled sheet at the conditions shown in Table 3B, the scale was removed by pickling, and cold-rolled at the reduction shown in Table 3B. Then, intermediate annealing was performed in an oxidation-free atmosphere, and intermediate annealing was performed at the annealing temperature shown in Table 3B for 30 seconds. Next, second cold-rolling (skin pass) was performed at the reduction shown in Table 3B.

[0333] To investigate the texture after the skin pass, a portion of the steel sheet was cut, and the cut test piece was reduced in thickness to 1 / 2 thickness, and EBSD observation was performed on the machined surface (step interval: 100 nm) according to the above procedure. The area of each orientation grain and the average KAM value obtained by the EBSD observation were used to calculate S tyl / S tot , S 100 / S tot , S 100 / S tra , K 100 / K tyl .

[0334] Further, the steel sheet after the skin pass was subjected to first heat treatment at the conditions shown in Table 3B. After the first heat treatment, to investigate the texture, a portion of the steel sheet was cut, and the cut test piece was reduced in thickness to 1 / 2 thickness, and EBSD observation was performed on the machined surface. The area of each orientation grain, the average KAM value, and the average crystal grain size shown in Table 4 were obtained by the EBSD observation.

[0335] Further, as the second heat treatment, the steel sheet was subjected to annealing at a temperature of 800°C for 2 hours. From the steel sheet after the second heat treatment, a 55 mm square test piece was used as a measurement sample. The sample was taken using a shearing machine. Then, similarly to the first embodiment, the magnetic properties, the iron loss W10 / 400 (average value of the rolling direction and the width direction), W15 / 50 (C), W15 / 50 (L), were measured, and W15 / 50 (C) / W15 / 50 (L) was calculated. The measurement results are shown in Table 4.

[0336] [Table 3A]

[0337]

[0338] [Table 3B]

[0339]

[0340] [Table 4]

[0341]

[0342] The underlines in Table 3A, Table 3B and Table 4 indicate conditions deviating from the scope of the present application. No. 201 to No. 207, No. 215 to No. 237, No. 247 to No. 250 as the examples of the application are all values of good W10 / 400.

[0343] On the other hand, No. 208 as the comparative example has a high Mn concentration, and the value on the left side of (1) is higher than 0.00 (a component of α-γ phase transition), and due to this, the area ratio S tyl / S tot deviates from the range of (10) and (11). As a result, the W10 / 400 is high. No. 209 to No. 214 as the comparative examples are not suitable for at least any one of the temperature in the annealing of the hot-rolled sheet, the temperature in the intermediate annealing, the reduction ratio in the cold rolling, the reduction ratio in the skin pass rolling, and the temperature in the first heat treatment, and as a result, any one of (10) to (15) is not satisfied, and as a result, the W10 / 400 is high. 100 / S tot In addition, No. 238 to No. 246 as the comparative examples deviate from the scope of the chemical components of the present application, and as a result, (10) to (11) are not satisfied, and the W10 / 400 is increased, or a fracture occurs at the time of the cold rolling.

[0344] (Third Embodiment)

[0345] (Third Embodiment)

[0346] A steel ingot having the chemical components shown in Table 5A was produced by casting molten steel. Here, the value on the left side of (1) indicates the value on the left side of (1) described above. Subsequently, the produced steel ingot was heated to 1150°C, and hot-rolled to be rolled in a manner so as to have the sheet thickness shown in Table 5B. Then, after the finish rolling, water cooling was performed, and the hot-rolled sheet was coiled. The temperature at the stage of the final pass of the finish rolling (the final temperature) at this time was 830°C, and the coiling temperature was in the range of 500 to 700°C.

[0347] Subsequently, the hot-rolled sheet was subjected to the hot-rolled sheet annealing for 30 seconds in the conditions shown in Table 5B, and the scale was removed by pickling, and the cold rolling was performed at the reduction ratio shown in Table 5B. Then, the intermediate annealing was performed in a non-oxidizing atmosphere, and the intermediate annealing was performed at 800°C for 30 seconds. Subsequently, the second cold rolling (skin pass rolling) was performed at the reduction ratio shown in Table 5B.

[0348] In order to investigate the texture after the skin pass rolling, a part of the sheet was cut, and the cut test piece was reduced in thickness to 1 / 2 thickness, and the EBSD observation was performed on the processed surface in the above-described manner (step interval: 100 nm). The S tyl / S tot、S 100 / S tot 、S 100 / S tra , K 100 / K tyl .

[0349] Furthermore, the skin-pass rolled steel sheets were not subjected to the first heat treatment, but to the second heat treatment under the conditions shown in Table 5B. After the second heat treatment, a portion of the steel sheet was cut to investigate the texture. This cut specimen was then reduced to 1 / 2 its thickness, and EBSD observation was performed on the processed surface. The EBSD observation yielded the area and average grain size of the types shown in Table 6.

[0350] After the second heat treatment, 55 mm square specimens were taken from the steel plates as test samples. The specimens were sheared. Similar to the first example, the magnetic properties of the steel plates were measured for iron loss (W10 / 400) (average value in the rolling and width directions), W15 / 50(C), and W15 / 50(L). W15 / 50(C) / W15 / 50(L) were calculated. Table 6 shows the measurement results.

[0351] [Table 5A]

[0352]

[0353] [Table 5B]

[0354]

[0355] [Table 6]

[0356]

[0357] The underlined conditions in Table 5A, Table 5B, and Table 6 indicate conditions outside the scope of the present invention. Inventive Examples No. 301 to No. 308, No. 316 to No. 333, and No. 344 all have good values ​​for iron loss W10 / 400.

[0358] On the other hand, the Mn concentration of No. 309 as a comparative example is high, and the value on the left side of the formula (1) is higher than 0.00 (the component of the α-γ phase transition). tyl / S tot and S 100 / S tot They are out of the range of formula (20) and formula (21), respectively. As a result, the iron loss W10 / 400 is high.

[0359] As comparative examples, No. 310 to No. 315 have unsuitable temperatures in hot-rolled sheet annealing and / or unsuitable reduction ratios in cold rolling, and therefore do not satisfy at least one of equations (20) to (24). As a result, the iron loss W10 / 400 is high.

[0360] In addition, No. 334 to No. 343 as comparative examples have chemical compositions outside the range of the present invention and do not satisfy equations (20) to (21), resulting in increased iron loss W10 / 400 or fracture during cold rolling.

[0361] (Fourth embodiment)

[0362] By casting molten steel, a steel ingot having the chemical composition shown in Table 7A is produced. Here, the left side of formula (1) represents the value of the left side of the formula (1). Thereafter, the produced steel ingot is heated to 1150°C and hot rolled to form a plate thickness shown in Table 7B. Then, after the finish rolling is completed, water cooling is performed and the hot-rolled steel plate is coiled. At this time, the temperature of the final pass of the finish rolling (final temperature) is 830°C, and the coiling temperature is in the range of 500 to 700°C.

[0363] Next, the hot-rolled steel sheets were annealed for 30 seconds under the conditions shown in Table 7B, descaled by pickling, and cold rolled at the reduction ratios shown in Table 7B. Intermediate annealing was then performed in a non-oxidizing atmosphere at 800°C for 30 seconds. A second cold rolling (skin pass rolling) was then performed at the reduction ratios shown in Table 7B.

[0364] Next, a first heat treatment was performed at 800° C. for 30 seconds.

[0365] After the first heat treatment, a portion of the steel plate was cut to investigate the texture. The cut specimen was then reduced to 1 / 2 thickness and EBSD observation (step interval: 100 nm) was performed on the processed surface. The area, average KAM value, and average grain size of the oriented grains were obtained through EBSD observation. tyl / S tot 、S 100 / S tot 、S 100 / S tra , K 100 / K tyl d 100 / d ave d 100 / d tyl .

[0366] The steel plate after the first heat treatment was then subjected to a second heat treatment under the conditions shown in Table 7B. After the second heat treatment, a portion of the steel plate was cut to investigate the texture. This test piece was then reduced to 1 / 2 the thickness, and EBSD observation was performed on the processed surface. The EBSD observation yielded the area and average grain size of the types shown in Table 8.

[0367] After the second heat treatment, 55 mm square specimens were taken from the steel plates as test samples. The specimens were sheared. Similar to the first example, the magnetic properties of iron loss (W10 / 400) (average value in the rolling and width directions), W15 / 50(C), and W15 / 50(L) were measured to determine W15 / 50(C) / W15 / 50(L). Table 8 shows the measurement results.

[0368] [Table 7A]

[0369]

[0370] [Table 7B]

[0371]

[0372] [Table 8]

[0373]

[0374] The underlined conditions in Table 7A, Table 7B, and Table 8 represent conditions outside the scope of the present invention. Inventive Examples No. 401 to No. 408, No. 421 to No. 438, and No. 448 all have good values ​​for iron loss W10 / 400.

[0375] On the other hand, the Mn concentration of No. 409 as a comparative example is high, and the value on the left side of formula (1) is higher than 0.00 (the component of α-γ phase transition). tyl / S tot and S 100 / S tot The results are outside the ranges of equations (20) and (21), respectively. As a result, the iron loss W10 / 400 is high. As for comparative examples No. 410 to No. 420, the temperature during hot-rolled sheet annealing and / or the rolling reduction during cold rolling are not suitable, so at least one of equations (20) to (24) is not satisfied. As a result, the iron loss W10 / 400 is high.

[0376] In addition, No. 439 to No. 447 as comparative examples have chemical compositions outside the range of the present invention and do not satisfy equations (20) to (21), resulting in increased iron loss W10 / 400 or fracture during cold rolling.

[0377] (Fifth Embodiment)

[0378] By casting molten steel, a steel ingot having the chemical components shown in Table 9A was produced. Here, the value of the left side of the aforementioned (1) formula is indicated as the left side of the (1) formula. Thereafter, the produced steel ingot was heated to 1150°C, and hot-rolled to be rolled in a manner so as to have the sheet thickness shown in Table 9B. Then, after the finish rolling, water cooling was performed, and the hot-rolled steel sheet was coiled. The temperature at the stage of the final pass of the finish rolling (the final temperature) at this time was 830°C, and the coiling temperature was in the range of 500 to 700°C.

[0379] Next, the hot-rolled steel sheet was subjected to hot-rolled sheet annealing for 30 seconds under the conditions shown in Table 9B, and the scale was removed by pickling, and cold-rolled at a reduction ratio shown in Table 9B. Also, intermediate annealing was performed in an oxidation-free atmosphere, and the intermediate annealing was performed at 800°C for 30 seconds. Next, second cold-rolling (skin pass) was performed at a reduction ratio shown in Table 9B.

[0380] Next, in order to investigate the texture, a portion of the steel sheet was cut, and the cut test piece was reduced in thickness to 1 / 2 of the thickness, and EBSD observation was performed with respect to the processed surface (step interval: 100 nm). By the EBSD observation, the area of each type and the average KAM value shown in Table 8 were obtained.

[0381] Further, as the second heat treatment, the steel sheet was subjected to annealing at a temperature of 800°C for 2 hours. From the steel sheet after the second heat treatment, a test piece of 55 mm square was taken as a measurement sample. The test piece was taken using a shearing machine. Then, similarly to the first embodiment, the magnetic property of the iron loss W10 / 400 (average value of the rolling direction and the width direction), W15 / 50 (C), W15 / 50 (L) was measured, and W15 / 50 (C) / W15 / 50 (L) was obtained. The measurement results are shown in Table 10.

[0382] [Table 9A]

[0383]

[0384] [Table 9B]

[0385]

[0386] [Table 10]

[0387]

[0388] As the inventive examples of No. 501 to No. 515, each satisfied the (3) formula to the (9) formula, and each was a good value of the iron loss W10 / 400.

[0389] Industrial applicability

[0390] According to the present invention, the area and area ratio of specific crystal orientations in a cross section parallel to the steel sheet surface are appropriate, so excellent magnetic properties can be obtained even after shearing. Therefore, the present invention has high industrial applicability.

Claims

1. A non-oriented electromagnetic steel sheet, characterized in that: It has the following chemical components: In mass%, contains Si: 1.50% to 4.00%, One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au: less than 2.50% in total, C: 0.0100% or less, sol.Al: 4.00% or less, S: 0.0400% or less, N: 0.0100% or less, Sn: 0.00% to 0.40%, Sb: 0.00% to 0.40%, P：0.00％～0.40％、 Cr：0.001％～0.100％、 B：0.0000％～0.0050％、 O: 0.0000% to 0.0200%, 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 Mn content is expressed as [Mn] by mass%, the Ni content is expressed as [Ni] by mass%, the Co content is expressed as [Co] by mass%, the Pt content is expressed as [Pt] by mass%, the Pb content is expressed as [Pb] by mass%, the Cu content is expressed as [Cu] by mass%, the Au content is expressed as [Au] by mass%, the Si content is expressed as [Si] by mass%, and the sol.Al content is expressed as [sol.Al] by mass%, the following formula (1) is satisfied: ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])≦0.00%···(1) The rest is composed of Fe and impurities. Furthermore, when observing by EBSD in a plane parallel to the steel plate surface, the total area is defined as S tot , let the area of ​​{100} oriented grains be S 100 The area of ​​oriented grains with a Taylor factor M exceeding 2.8 based on the following formula (2) is defined as S tyl The total area of ​​the oriented grains with the Taylor factor M being less than 2.8 is defined as S tra The average KAM value of the {100} oriented grains is set as K 100 The average KAM value of the oriented grains with Taylor factor M exceeding 2.8 is set as K tyl In the case of , the following equations (3) to (6) are satisfied: M=(cosφ×cosλ) -1 ···(2) 0.20≦S tyl / S tot ≦0.85···(3) 0.05≦S 100 / S tot ≦0.80···(4) S 100 / S tra ≧0.50···(5) K 100 / K tyl ≦0.990···(6) In formula (2), φ represents the angle between the stress vector and the sliding direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the sliding surface of the crystal.

2. The non-oriented electrical steel sheet according to claim 1, wherein Furthermore, the average KAM value of the oriented grains with the Taylor factor M being 2.8 or less is set as K tra When , the following formula (7) is satisfied: K 100 / K tra <1.010···(7)。 3. The non-oriented electrical steel sheet according to claim 1 or 2, wherein: Furthermore, when the area of ​​the {110} oriented grains is set as S 110 When , the following formula (8) is satisfied: S 100 / S 110 ≧1.00···(8) Wherein, (8) is assumed to be even if the area ratio S 100 / S 110 The divergence to infinity is also true.

4. The non-oriented electrical steel sheet according to claim 1 or 2, wherein: Furthermore, when the average KAM value of {110} oriented grains is set as K 110 When , the following formula (9) is satisfied: K 100 / K 110 <1.010···(9)。 5. A non-oriented electrical steel sheet, characterized in that: It has the following chemical components: In mass%, contains Si: 1.50% to 4.00%, One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au: less than 2.50% in total, C: 0.0100% or less, sol.Al: 4.00% or less, S: 0.0400% or less, N: 0.0100% or less, Sn: 0.00% to 0.40%, Sb: 0.00% to 0.40%, P：0.00％～0.40％、 Cr：0.001％～0.100％、 B：0.0000％～0.0050％、 O: 0.0000% to 0.0200%, 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 Mn content is expressed as [Mn] by mass%, the Ni content is expressed as [Ni] by mass%, the Co content is expressed as [Co] by mass%, the Pt content is expressed as [Pt] by mass%, the Pb content is expressed as [Pb] by mass%, the Cu content is expressed as [Cu] by mass%, the Au content is expressed as [Au] by mass%, the Si content is expressed as [Si] by mass%, and the sol.Al content is expressed as [sol.Al] by mass%, the following formula (1) is satisfied: ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])≦0%···(1) The rest is composed of Fe and impurities. Furthermore, when observing by EBSD in a plane parallel to the steel plate surface, the total area is defined as S tot , let the area of ​​{100} oriented grains be S 100 The area of ​​oriented grains with a Taylor factor M greater than 2.8 based on the following formula (2) is defined as S tyl The total area of ​​the oriented grains with the Taylor factor M being less than 2.8 is defined as S tra The average KAM value of the {100} oriented grains is set as K 100 The average KAM value of the oriented grains with Taylor factor M exceeding 2.8 is set as K tyl , the average crystal grain size of the observation area is set as d ave The average grain size of the {100} oriented grains is set to d 100 The average crystal grain size of the oriented grains with the Taylor factor M exceeding 2.8 is set as d tyl In the case of , the following equations (10) to (15) are satisfied: M=(cosφ×cosλ) -1 ···(2) S tyl / S tot ≦0.70···(10) 0.20≦S 100 / S tot ···(11) S 100 / S tra ≧0.55···(12) K 100 / K tyl ≦1.010···(13) d 100 / d ave >1.00···(14) d 100 / d tyl >1.00···(15) In formula (2), φ represents the angle between the stress vector and the sliding direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the sliding surface of the crystal.

6. The non-oriented electrical steel sheet according to claim 5, wherein: Furthermore, the average KAM value of the oriented grains with the Taylor factor M being 2.8 or less is set as K tra When , the following formula (16) is satisfied: K 100 / K tra <1.010···(16)。 7. The non-oriented electrical steel sheet according to claim 5 or 6, characterized in that: Furthermore, when the average crystal grain size of the oriented grains having the Taylor factor M of 2.8 or less is set to d tra In the case of , the following formula (17) is satisfied: d 100 / d tra >1.00···(17)。 8. The non-oriented electrical steel sheet according to claim 5 or 6, wherein: Furthermore, the area of ​​the {110} oriented grains is defined as S 110 When , the following formula (18) is satisfied: S 100 / S 110 ≧1.00···(18) Here, Equation (18) assumes that even if the area ratio S 100 / S 110 The divergence to infinity is also true.

9. The non-oriented electrical steel sheet according to claim 5 or 6, wherein: Furthermore, the average KAM value of {110} oriented grains is set as K 110 When , the following formula (19) is satisfied: K 100 / K 110 <1.010···(19)。 10. A method for producing a non-oriented electrical steel sheet, the method for producing a non-oriented electrical steel sheet according to any one of claims 5 to 9, characterized in that: The non-oriented electrical steel sheet according to any one of claims 1 to 4 is heat-treated at a temperature of 700° C. to 950° C. for 1 second to 100 seconds.

11. A non-oriented electromagnetic steel sheet, characterized in that: It has the following chemical components: In mass%, contains Si: 1.50% to 4.00%, One or more selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu, and Au: less than 2.50% in total, C: 0.0100% or less, sol.Al: 4.00% or less, S: 0.0400% or less, N: 0.0100% or less, Sn: 0.00% to 0.40%, Sb: 0.00% to 0.40%, P：0.00％～0.40％、 Cr：0.001％～0.100％、 B：0.0000％～0.0050％、 O: 0.0000% to 0.0200%, 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 Mn content is expressed as [Mn] by mass%, the Ni content is expressed as [Ni] by mass%, the Co content is expressed as [Co] by mass%, the Pt content is expressed as [Pt] by mass%, the Pb content is expressed as [Pb] by mass%, the Cu content is expressed as [Cu] by mass%, the Au content is expressed as [Au] by mass%, the Si content is expressed as [Si] by mass%, and the sol.Al content is expressed as [sol.Al] by mass%, the following formula (1) is satisfied: ([Mn]+[Ni]+[Co]+[Pt]+[Pb]+[Cu]+[Au])-([Si]+[sol.Al])≦0%···(1) The rest is composed of Fe and impurities. Furthermore, when observing by EBSD in a plane parallel to the steel plate surface, the total area is defined as S tot , let the area of ​​{100} oriented grains be S 100 The area of ​​oriented grains with a Taylor factor M greater than 2.8 based on the following formula (2) is defined as S tyl The total area of ​​the oriented grains with the Taylor factor M being less than 2.8 is defined as S tra , the average crystal grain size of the observation area is set as d ave The average grain size of the {100} oriented grains is set to d 100 The average crystal grain size of the oriented grains with Taylor factor M higher than 2.8 is set as d tyl In the case of , the following equations (20) to (24) are satisfied: M=(cosφ×cosλ) -1 ···(2) S tyl / S tot <0.55···(20) S 100 / S tot >0.30···(21) S 100 / S tra ≧0.60···(22) d 100 / d ave ≧0.95···(23) d 100 / d tyl ≧0.95···(24) Here, φ in formula (2) represents the angle between the stress vector and the sliding direction vector of the crystal, and λ represents the angle between the stress vector and the normal vector of the sliding surface of the crystal.

12. The non-oriented electrical steel sheet according to claim 11, wherein: Furthermore, when the average crystal grain size of the oriented grains having the Taylor factor M of 2.8 or less is set to d tra In the case of , the following formula (25) is satisfied d 100 / d tra ≧0.95···(25)。 13. A method for manufacturing a non-oriented electrical steel sheet, characterized in that: The non-oriented electrical steel sheet according to any one of claims 1 to 9 is heat treated at 950°C to 1050°C for 1 to 100 seconds or at 700°C to 900°C for more than 1000 seconds.

Images