Specification
Title of invention: Non-oriented electrical steel sheet and method for manufacturing non-oriented electrical steel sheet
Technical field
[0001]
　The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing a non-oriented electrical steel sheet.
　The present application claims priority based on Japanese Patent Application No. 2018-026109 filed in Japan on February 16, 2018, and the content thereof is incorporated herein.
Background technology
[0002]
　The non-oriented electrical steel sheet is used, for example, in an iron core of a motor, and the non-oriented electrical steel sheet is required to have excellent magnetic characteristics, for example, high magnetic flux density. Up to now, various techniques such as those disclosed in Patent Documents 1 to 9 have been proposed, but it is difficult to obtain a sufficient magnetic flux density.
Prior art documents
Patent literature
[0003]
Patent Document 1: Japanese Unexamined Patent Publication No. 2-133523
Patent Document 2: Japanese Unexamined Patent Publication No. 5-140648
Patent Document 3: Japanese Unexamined Patent Publication No. 6-057332
Patent Document 4: Japanese Unexamined Patent Publication No. 2002-241905 JP
Patent Document 5: Japanese Patent 2004-197217 JP
Patent Document 6: Japanese Patent 2004-332042 JP
Patent Document 7: Japanese Patent 2005-067737 JP
Patent Document 8: Japanese Patent 2011 -140683 gazette
Patent Document 9: Japanese Patent Laid-Open No. 2010-1557
Summary of the invention
Problems to be Solved by the Invention
[0004]
　An object of the present invention is to provide a non-oriented electrical steel sheet that can obtain a higher magnetic flux density without deteriorating iron loss, and a method for manufacturing the non-oriented electrical steel sheet.
Means for solving the problem
[0005]
　The present inventors have diligently studied to solve the above problems. As a result, it became clear that it is important to make the relationship between chemical composition and crystal orientation appropriate. It was also clarified that this relationship should be maintained throughout the thickness direction of the non-oriented electrical steel sheet. The isotropy of the texture in the rolled steel sheet is high in the region close to the rolling surface and usually decreases as the distance from the rolling surface increases. For example, in the invention described in Patent Document 9 above, it is shown in the experimental data disclosed in the same document that the isotropy of the texture decreases as the measurement position of the texture moves away from the surface layer. The present inventors have found that it is necessary to preferably control the crystal orientation even inside the non-oriented electrical steel sheet.
　In Patent Document 9 described above, crystal orientations are accumulated near the cube orientation in the vicinity of the surface layer of the steel sheet, whereas gamma fiber texture is developed in the central layer of the steel sheet. Patent Document 9 describes that a new feature is that the textures are significantly different between the steel sheet surface layer and the steel sheet center layer. Further, generally, when a rolled steel sheet is annealed and recrystallized, crystal orientations are accumulated near the cube orientations {200} and {110} near the surface layer of the steel sheet, and a gamma fiber texture is formed in the steel sheet central layer. A certain {222} develops. For example, “Effect of cold rolling conditions on r value of ultra low carbon cold rolled steel sheet”, Hashimoto et al., Iron and Steel, Vol. 76, No. 1 (1990), p. In No. 50, 0.0035% C-0.12% Mn-0.001% P-0.0084% S-0.03% Al-0.11% Ti steel was cold rolled at a rolling reduction of 73%, It is shown that in the steel sheet obtained by annealing at 750° C. for 3 hours, the sheet thickness center has a higher (222), a lower (200) and a lower (110) than the surface layer.
　On the other hand, the present inventor needs to integrate the crystal orientation near {200} which is the cube orientation near the surface layer of the steel sheet, and also to integrate the crystal orientation near {200} in the steel sheet center layer. I found out.
[0006]
　In the production of such a non-oriented electrical steel sheet, the columnar crystal ratio and the average crystal grain size of the steel strip to be subjected to cold rolling are controlled, the rolling reduction of cold rolling is controlled, and the strip tension during finish annealing is controlled. It was also revealed that it is important to control the cooling rate.
[0007]
　As a result of further earnest studies based on such findings, the present inventors have conceived various aspects of the invention described below.
[0008]
(1) The non-oriented electrical steel sheet according to one aspect of the present invention is, in mass %, C: 0.0030% or less, Si: 2.00% or less, Al: 1.00% or less, Mn: 0.10. % To 2.00%, S: 0.0030% or less, one or more selected from the group consisting of Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn and Cd: 0.0015% in total Expressed by the formula 1 by defining ˜0.0100%, Si content (mass %) as [Si], Al content (mass %) as [Al], and Mn content (mass %) as [Mn]. Parameter Q: 2.00 or less, Sn: 0.00% to 0.40%, Cu: 0.00% to 1.00%, and the balance: Fe and impurities. {100} crystal orientation strength, {310} crystal orientation strength, {411} crystal orientation strength, {521} crystal orientation strength, {111} crystal orientation strength, {211} crystal orientation strength, {332} in the center of plate thickness The crystal orientation intensity and the {221} crystal orientation intensity are defined as I 100 , I 310 , I 411 , I 521 , I 111 , I 211 , I 332 , and I 221, respectively, and the parameter R represented by Equation 2 is 0. It is 80 or more.
　Q=[Si]+2×[Al]−[Mn] (Formula 1)
　R=(I 100 +I 310 +I 411 +I 521 )/(I 111 +I 211 +I 332 +I 221 ) (Formula 2)
(2) In the non-oriented electrical steel sheet according to (1) above, Sn: 0.02% to 0.40%, or Cu: 0.10% to 1.00%, or both may be satisfied.
(3) A method for producing a non-oriented electrical steel sheet according to another aspect of the present invention is the method for producing a non-oriented electrical steel sheet according to (1) or (2) above, which comprises a continuous casting step for molten steel. , A hot rolling process of a steel ingot obtained by the continuous casting process, a cold rolling process of a steel strip obtained by the hot rolling process, and a finish of a cold rolled steel sheet obtained by the cold rolling process And an annealing step, wherein the molten steel has the chemical composition described in (1) or (2) above, and the steel strip has a columnar crystal ratio of 80% or more in area fraction and an average crystal ratio. The grain size is 0.10 mm or more, and the rolling reduction in the cold rolling step is 90% or less.
(4) In the method for producing a non-oriented electrical steel sheet according to (3) above, in the continuous casting step, the temperature difference between one surface and the other surface of the steel ingot during solidification may be 40° C. or more. Good.
(5) In the method for manufacturing a non-oriented electrical steel sheet according to (3) or (4) above, in the hot rolling step, the starting temperature of hot rolling is set to 900° C. or lower, and the steel strip is wound. The temperature may be 650° C. or lower.
(6) In the method for manufacturing a non-oriented electrical steel sheet according to any one of (3) to (5) above, the strip tension in the finish annealing step is set to 3 MPa or less, and the cooling rate at 950°C to 700°C. May be 1° C./second or less.
(7) A method for manufacturing a non-oriented electrical steel sheet according to another aspect of the present invention is the method for manufacturing a non-oriented electrical steel sheet according to (1) or (2) above, which includes a rapid solidification step of molten steel. A cold rolling step of the steel strip obtained by the rapid solidification step and a finish annealing step of the cold rolled steel sheet obtained by the cold rolling step, wherein the molten steel has the above (1) or (2). ), the steel strip has a columnar crystal ratio of 80% or more in area fraction, an average crystal grain size of 0.10 mm or more, and a reduction ratio in the cold rolling step. Is 90% or less.
(8) In the method for manufacturing a non-oriented electrical steel sheet according to the above (7), in the rapid solidification step, the molten steel is solidified by using a cooling body for moving and renewing, and the molten steel is injected into the cooling body for moving and renewing. The temperature of the molten steel may be higher than the solidification temperature of the molten steel by 25° C. or more.
(9) In the method for manufacturing a non-oriented electrical steel sheet according to (7) or (8) above, in the rapid solidification step, the molten steel is solidified using a cooling body that is moved and renewed, and the solidification of the molten steel is completed. The average cooling rate until the coiling of the steel strip may be 1,000 to 3,000° C./min.
(10) In the method for producing a non-oriented electrical steel sheet according to any one of (7) to (9), the strip tension in the finish annealing step is set to 3 MPa or less, and the cooling rate at 950°C to 700°C is set. May be 1° C./second or less.
Effect of the invention
[0009]
　According to the present invention, since the relationship between the chemical composition and the crystal orientation is appropriate, it is possible to obtain a high magnetic flux density without degrading iron loss.
MODE FOR CARRYING OUT THE INVENTION
[0010]
　Hereinafter, embodiments of the present invention will be described in detail.
[0011]
　First, the chemical composition of the non-oriented electrical steel sheet according to the embodiment of the present invention and the molten steel used for its production will be described. Although the details will be described later, the non-oriented electrical steel sheet according to the embodiment of the present invention is manufactured through casting of molten steel and hot rolling, rapid solidification of molten steel, cold rolling, and finish annealing. Therefore, the chemical compositions of the non-oriented electrical steel sheet and the molten steel take into consideration not only the characteristics of the non-oriented electrical steel sheet but also these treatments. In the following description, “%”, which is a unit of the content of each element contained in the non-oriented electrical steel sheet or the molten steel, means “mass %” unless otherwise specified. The non-oriented electrical steel sheet according to this embodiment has C: 0.0030% or less, Si: 2.00% or less, Al: 1.00% or less, Mn: 0.10% to 2.00%, S: 0.0030% or less, one or more selected from the group consisting of Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn and Cd: 0.0015% to 0.0100% in total, Si content (Mass %) is defined as [Si], Al content (mass %) is defined as [Al], and Mn content (mass %) is defined as [Mn]. It has a chemical composition represented by Sn: 0.00% to 0.40%, Cu: 0.00% to 1.00%, and the balance: Fe and impurities. Examples of the impurities include those contained in raw materials such as ores and scraps, and those contained in the manufacturing process.
　Q=[Si]+2×[Al]−[Mn] (Equation 1)
[0012]
　(C: 0.0030% or less)
　C increases iron loss and causes magnetic aging. Therefore, the lower the C content, the better, and it is not necessary to set its lower limit. The lower limit of the C content may be 0%, 0.0001%, 0.0002%, 0.0005%, or 0.0010%. Such a phenomenon is remarkable when the C content exceeds 0.0030%. Therefore, the C content is 0.0030% or less. The upper limit of the C content may be 0.0028%, 0.0025%, 0.0022%, or 0.0020%.
[0013]
　(Si: 0.30% or more and 2.00% or less)
　Si is a component having a function of reducing iron loss, as is well known, and is contained to exhibit this function. If the Si content is less than 0.30%, the iron loss reducing effect is not sufficiently exhibited, so the lower limit of the Si content is made 0.30%. For example, the lower limit of the Si content may be 0.90%, 0.95%, 0.98%, or 1.00%. On the other hand, when the Si content increases, the magnetic flux density decreases, rolling workability deteriorates, and the cost increases, so the content is made 2.0% or less. The upper limit of the Si content may be 1.80%, 1.60%, 1.40%, or 1.10%.
[0014]
　(Al: 1.00% or less)
　Al has the effect of increasing electric resistance and reducing iron loss, like Si. Further, when the non-oriented electrical steel sheet contains Al, the texture obtained by primary recrystallization is a crystal whose plane parallel to the plate surface is a {100} plane (hereinafter, may be referred to as “{100} crystal”). ) Is likely to be a developed one. Al is contained to achieve this effect. For example, the lower limit of the Al content may be 0%, 0.01%, 0.02%, or 0.03%. On the other hand, if the Al content exceeds 1.00%, the magnetic flux density decreases as in the case of Si, so the content is made 1.00% or less. The upper limit of the Al content may be 0.50%, 0.20%, 0.10%, or 0.05%.
[0015]
　(Mn: 0.10% to 2.00%)
　Mn increases electrical resistance, reduces eddy current loss, and reduces iron loss. When Mn is contained, the texture obtained by the primary recrystallization tends to have a {100} crystal developed in the plane parallel to the plate surface. The {100} crystal is a crystal suitable for uniformly improving the magnetic characteristics in all directions in the plate surface. Further, the higher the Mn content, the higher the MnS precipitation temperature, and the larger the MnS that precipitates. Therefore, as the Mn content is higher, fine MnS having a grain size of about 100 nm that hinders recrystallization and crystal grain growth in finish annealing is less likely to be deposited. If the Mn content is less than 0.10%, these effects cannot be sufficiently obtained. Therefore, the Mn content is set to 0.10% or more. The lower limit of the Mn content may be 0.12%, 0.15%, 0.18%, or 0.20%. On the other hand, if the Mn content exceeds 2.00%, the crystal grains do not grow sufficiently in the final annealing, and the iron loss increases. Therefore, the Mn content is 2.00% or less. The upper limit of the Mn content may be 1.00%, 0.50%, 0.30%, or 0.25%.
[0016]
　(S: 0.0030% or less)
　S is not an essential element, and is contained as an impurity in steel, for example. S inhibits recrystallization and grain growth during finish annealing due to the precipitation of fine MnS. Therefore, the lower the S content, the better. Such an increase in iron loss is remarkable when the S content exceeds 0.0030%. Therefore, the S content is 0.0030% or less. The lower limit of the S content need not be specified in particular, and may be 0%, 0.0005%, 0.0010%, or 0.0015%, for example.
[0017]
　(One or more selected from the group consisting of Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn and Cd: 0.0015% to 0.0100% in total)
　Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn and Cd react with S in molten steel during casting or rapid solidification of molten steel to form sulfides or oxysulfides or precipitates of both. Hereinafter, Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn and Cd may be collectively referred to as "coarse precipitate forming element". The particle size of the precipitate of the coarse precipitate forming element is about 1 μm to 2 μm, which is much larger than the particle size (about 100 nm) of the fine precipitate such as MnS, TiN, and AlN. For this reason, these fine precipitates adhere to the precipitates of the coarse precipitate forming element, and it is difficult to inhibit the recrystallization and the growth of crystal grains in the finish annealing. If the total content of coarse precipitate forming elements is less than 0.0015%, these effects cannot be sufficiently obtained. Therefore, the total content of coarse precipitate forming elements is 0.0015% or more. The lower limit value of the content of the coarse precipitate forming element may be 0.0018%, 0.0020%, 0.0022%, or 0.0025% in total. On the other hand, if the total content of coarse precipitate-forming elements exceeds 0.0100%, the total amount of sulfides or oxysulfides or both of them becomes excessive, and recrystallization and grain growth in finish annealing are inhibited. .. Therefore, the total content of coarse precipitate forming elements is set to 0.0100% or less. The total upper limit of the content of coarse precipitate forming elements may be 0.0095%, 0.0090%, 0.0080%, or 0.0070%.
　In addition, according to the experimental results of the present inventors, as long as the content of the coarse precipitate-forming element is within the above range, the effect of the coarse precipitate is surely expressed, and the crystal grains of the non-oriented electrical steel sheet are sufficient. Was growing up. Therefore, it is not necessary to particularly limit the form and composition of the coarse precipitate formed by the coarse precipitate forming element. On the other hand, in the non-oriented electrical steel sheet according to the present embodiment, the total mass of S contained in the sulfide or oxysulfide of the coarse precipitate forming element is 40% of the total mass of S contained in the non-oriented electrical steel sheet. The above is preferable. As described above, the coarse precipitate forming element reacts with S in the molten steel during casting or rapid solidification of the molten steel to form a sulfide or an oxysulfide or a precipitate of both of them. Therefore, the fact that the ratio of the total mass of S contained in the sulfide or oxysulfide of the coarse precipitate forming element to the total mass of S contained in the non-oriented electrical steel sheet is high means that a sufficient amount of coarse precipitate is formed. It means that the element is contained in the non-oriented electrical steel sheet, and fine precipitates such as MnS are effectively attached to the precipitates. Therefore, the higher the ratio is, the more the recrystallization and the growth of crystal grains in the finish annealing are promoted, and the excellent magnetic characteristics are obtained. The above ratio is achieved, for example, by controlling the production conditions at the time of casting or rapid solidification of molten steel as described below.
[0018]
　(Parameter Q: 2.00 or less) For the
　parameter Q, the Si content (mass %) is defined as [Si], the Al content (mass %) is defined as [Al], and the Mn content (mass %) is defined as [Mn]. Then, the value is represented by Equation 1.
　Q=[Si]+2×[Al]−[Mn] (Equation 1) By
　setting the parameter Q to 2.00 or less, the transformation from austenite to ferrite during cooling after continuous casting of molten steel or after rapid solidification ( (γ→α transformation) is likely to occur, and the {100}<0vw> texture of columnar crystals is sharpened more. The upper limit value of the parameter Q may be 1.50%, 1.20%, 1.00%, 0.90%, or 0.88%. The lower limit value of the parameter Q is not particularly limited, but may be 0.20%, 0.40%, 0.80%, 0.82%, or 0.85%, for example.
[0019]
　Sn and Cu are not essential elements, and the lower limit of their contents is 0%, but they are optional elements that may be appropriately contained within the predetermined amount in the non-oriented electrical steel sheet.
[0020]
　(Sn: 0.00% to 0.40%, Cu: 0.00% to 1.00%)
　Sn and Cu develop a crystal suitable for improving magnetic properties by primary recrystallization. For this reason, when Sn or Cu or both of them are contained, it is easy to obtain the texture in which the {100} crystal is developed, which is suitable for uniformly improving the magnetic properties in all directions in the plate surface, by the primary recrystallization. Sn suppresses oxidation and nitridation of the surface of the steel sheet during finish annealing, and suppresses variations in crystal grain size. Therefore, Sn, Cu, or both of them may be contained. In order to sufficiently obtain these effects, Sn: 0.02% or more, Cu: 0.10% or more, or both of them is preferable. The lower limit of the Sn content may be 0.05%, 0.08%, or 0.10%. The lower limit of the Cu content may be 0.12%, 0.15%, or 0.20%. On the other hand, if the Sn content exceeds 0.40%, the above-described effects are saturated, resulting in a high cost, or the growth of crystal grains is suppressed during finish annealing. Therefore, the Sn content is 0.40% or less. The upper limit of the Sn content may be 0.35%, 0.30%, or 0.20%. If the Cu content exceeds 1.00%, the steel sheet becomes brittle, which makes hot rolling and cold rolling difficult, and makes it difficult to pass through the annealing line for finish annealing. Therefore, the Cu content is 1.00% or less. The upper limit of the Cu content may be 0.80%, 0.60%, or 0.40%.
[0021]
　Next, the texture of the non-oriented electrical steel sheet according to the embodiment of the present invention will be described. In the non-oriented electrical steel sheet according to the present embodiment, {100} crystal orientation strength, {310} crystal orientation strength, {411} crystal orientation strength, {521} crystal orientation strength, and {111} crystal orientation at the center of the plate thickness. Intensity, {211} crystal orientation intensity, {332} crystal orientation intensity, and {221} crystal orientation intensity are defined as I 100 , I 310 , I 411 , I 521 , I 111 , I 211 , I 332 , and I 221 , respectively. The parameter R expressed by Equation 2 is 0.80 or more. In addition, the plate thickness center part (usually sometimes referred to as 1/2T part) is a depth of about 1/2 of the plate thickness T of the non-oriented electrical steel sheet from the rolling surface of the non-oriented electrical steel sheet. Means the area of ​​Sano. In other words, the plate thickness center means the intermediate surface of both rolling surfaces of the non-oriented electrical steel sheet and its vicinity.
　R=(I 100 +I 310 +I 411 +I 521 )/(I 111 +I 211 +I 332 +I 221 ) (Formula 2)
[0022]
　{310}, {411} and {521} are in the vicinity of {100}, and the sum of I 100 , I 310 , I 411 and I 521 is {100}-containing crystal orientation in the vicinity of {100}. The sum of intensities is shown. {211}, {332} and {221} are in the vicinity of {111}, and the sum of I 111 , I 211 , I 332 and I 221 is the crystal orientation of {111} including {111} itself. The sum of intensities is shown. When the parameter R in the central portion of the plate thickness is less than 0.80, the magnetic characteristics are deteriorated, such as a decrease in magnetic flux density and an increase in iron loss. Therefore, in the present component system, for example, when the thickness is 0.50 mm, the magnetic flux density B50 L in the rolling direction (L direction) is 1.79 T or more, and the magnetic flux density B50 in the rolling direction and the width direction (C direction) is Average value B50 L+C : 1.75 T or more, iron loss W15/50 L in rolling direction: 4.5 W/kg or less, average value W15/50 L+C of iron loss W15/50 in rolling direction and width direction : 5.0 W/kg or less can no longer exhibit the magnetic characteristics. The parameter R in the central part of the plate thickness is, for example, the difference between the temperature of the molten steel poured into the surface of the cooling body for moving and renewing and the solidification temperature of the molten steel, the temperature difference between one surface and the other surface of the slab during solidification. A desired value can be obtained by adjusting the amount of sulfide or oxysulfide produced, the cold rolling rate, and the like. The lower limit value of the parameter R at the center of the plate thickness may be 0.82, 0.85, 0.90, or 0.95. Since the parameter R in the central portion of the plate thickness is better to be high, it is not necessary to specify the upper limit thereof, but it may be set to 2.00, 1.90, 1.80, or 1.70, for example.
　The crystal orientation of the non-oriented electrical steel sheet according to this embodiment needs to be controlled as described above in the entire sheet. However, the isotropy of the texture in the rolled steel sheet is high in the region close to the rolling surface, and usually decreases as the distance from the rolling surface decreases. For example, “Effect of cold rolling conditions on r value of ultra low carbon cold rolled steel sheet”, Hashimoto et al., Iron and Steel, Vol. 76, No. 1 (1990), p. In No. 50, 0.0035% C-0.12% Mn-0.001% P-0.0084% S-0.03% Al-0.11% Ti steel was cold-rolled at a rolling reduction of 73%, It is shown that in the steel sheet obtained by annealing at 750° C. for 3 hours, the sheet thickness center has a higher (222), a lower (200) and a lower (110) than the surface layer.
　Therefore, if the parameter R is 0.8 or more in the central portion of the plate thickness, which is the region farthest from the rolling surface, equal or greater isotropy is achieved in other regions. For the above reasons, the crystal orientation of the non-oriented electrical steel sheet according to the present embodiment is defined in the plate thickness central portion.
[0023]
　{100} crystal orientation strength, {310} crystal orientation strength, {411} crystal orientation strength, {521} crystal orientation strength, {111} crystal orientation strength, {211} crystal orientation strength, {332} in the center of plate thickness The crystal orientation intensity and the {221} crystal orientation intensity can be measured by an X-ray diffraction method (XRD) or an electron backscatter diffraction (EBSD) method. Specifically, a plane that is parallel to the rolling surface of the non-oriented electrical steel sheet and has a depth of about ½ of the sheet thickness T is exposed from this rolling surface by an ordinary method. By performing XRD analysis or EBSD analysis, it is possible to measure each crystal orientation strength and calculate the parameter R in the central portion of the plate thickness. Since the diffraction intensities of the X-ray and the electron beam from the sample are different for each crystal orientation, it is possible to obtain the crystal orientation intensity based on the relative ratio with the random orientation sample as a reference.
[0024]
　Next, the magnetic characteristics of the non-oriented electrical steel sheet according to the embodiment of the present invention will be described. When the thickness of the non-oriented electrical steel sheet according to the present embodiment is 0.50 mm, for example, the magnetic flux density B50 L in the rolling direction (L direction) : 1.79 T or more, the rolling direction and the width direction (C direction). Average value of magnetic flux density B50 B50 L+C : 1.75 T or more, iron loss W15/50 L in rolling direction: 4.5 W/kg or less, average value W15/50 L+C of iron loss W15/50 in rolling direction and width direction : The magnetic characteristics represented by 5.0 W/kg or less can be exhibited. The magnetic flux density B50 is a magnetic flux density in a magnetic field of 5000 A/m, and the iron loss W15/50 is a magnetic flux density of 1.5 T and an iron loss at a frequency of 50 Hz.
[0025]
　Next, an example of a method for manufacturing a non-oriented electrical steel sheet according to this embodiment will be described below. However, as a matter of course, the method for manufacturing the non-oriented electrical steel sheet according to the present embodiment is not particularly limited. The non-oriented electrical steel sheet that satisfies the above requirements corresponds to the non-oriented electrical steel sheet according to the present embodiment even if it is obtained by a method other than the manufacturing method exemplified below.
　First, a first method for manufacturing a non-oriented electrical steel sheet according to this embodiment will be exemplarily described. In the first manufacturing method, continuous casting of molten steel, hot rolling, cold rolling, finish annealing and the like are performed.
[0026]
　In molten steel casting and hot rolling, molten steel having the above chemical composition is cast to produce a steel ingot such as a slab, and this hot rolling is performed, and the proportion of columnar crystals is 80% or more in area fraction, In addition, a steel strip having an average crystal grain size of 0.10 mm or more is obtained. During solidification, if the temperature difference between the outermost surface and the inside of the steel ingot or the temperature difference between one surface and the other surface of the steel ingot is sufficiently high, the crystal grains solidified on the surface of the steel ingot are perpendicular to the surface. Grows in the direction to form columnar crystals. In steel having a BCC structure, columnar crystals grow so that the {100} planes are parallel to the surface of the steel ingot. Before the columnar crystals develop from the surface to the center of the steel ingot, or from one surface of the steel ingot to the other surface, the temperature inside the steel ingot or the temperature on the other surface of the steel ingot decreases. Then, when the solidification temperature is reached, crystallization starts inside the steel ingot or on the other surface of the steel ingot. The crystal that crystallizes inside the steel ingot or on the other surface of the steel ingot grows equiaxedly and has a crystal orientation different from that of the columnar crystal.
　The columnar crystal ratio can be measured, for example, by the following procedure. First, the cross section of a steel strip is polished, and the cross section is etched with a picric acid-based etchant to reveal a solidified structure. Here, the steel strip cross section may be an L cross section parallel to the steel strip longitudinal direction or a C cross section perpendicular to the steel strip longitudinal direction, but it is generally the L cross section. In this cross section, when dendrite develops in the plate thickness direction and penetrates the entire plate thickness, it is determined that the columnar crystal ratio is 100%. If a granular black structure (equiaxed grains) other than dendrite is visible in the cross section, the value obtained by subtracting the thickness of this granular structure from the total thickness of the steel plate by the total thickness of the steel plate The crystal ratio.
　In the first manufacturing method, the γ→α transformation is likely to occur during cooling after continuous casting of molten steel, but the crystal structure that has undergone the γ→α transformation from the columnar crystal is also regarded as the columnar crystal. By undergoing the γ→α transformation, the {100}<0vw> texture of columnar crystals is further sharpened.
[0027]
　The columnar crystals have a {100}<0vw> texture desirable for uniformly improving the magnetic properties of the non-oriented electrical steel sheet, particularly the magnetic properties in all directions in the plane of the sheet. The {100}<0vw> texture is a texture in which crystals having a {100} plane parallel to the plate surface and a rolling direction of <0vw> are developed (v and w are arbitrary real numbers ( Unless v and w are both 0)). If the proportion of columnar crystals is less than 80%, it is not possible to obtain a texture in which {100} crystals have developed by finish annealing throughout the thickness direction of the non-oriented electrical steel sheet. In that case, as described above, the {100} crystal does not develop in the central part of the plate thickness of the steel sheet, and the {111} crystal, which is unfavorable to the magnetic properties, develops. The proportion of columnar crystals in the steel strip is set to 80% or more in order to form a texture in which {100} crystals have developed to the center of the plate thickness. As described above, the proportion of columnar crystals in the steel strip can be specified by observing the cross section of the steel strip with a microscope. However, the columnar crystal fraction of the steel strip cannot be accurately measured after the cold rolling or heat treatment described below is performed on the steel strip. Therefore, in the non-oriented electrical steel sheet according to the present embodiment, the columnar crystal ratio is not particularly specified.
　In the first manufacturing method, in order to set the columnar crystal ratio to 80% or more, for example, the temperature difference between one surface and the other surface of the steel ingot such as a cast piece during solidification is 40°C or more. And This temperature difference can be controlled by the mold cooling structure, material, mold taper, mold flux, and the like. When molten steel is cast under the condition that the proportion of such columnar crystals is 80% or more, sulfides or oxysulfides of Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn or Cd, or these Both are easily formed, and the formation of fine sulfides such as MnS is suppressed.
[0028]
　The smaller the average grain size of the steel strip, the larger the number of grains and the larger the area of ​​grain boundaries. In the recrystallization of finish annealing, the crystal grows from within the crystal grain and from the crystal grain boundary. The crystal growing from within the crystal grain is a {100} crystal which is desirable for magnetic properties, whereas the crystal growing from the crystal grain boundary. Is a crystal such as a {111}<112> crystal which is not desirable for magnetic properties. Therefore, the larger the average crystal grain size of the steel strip, the more easily the {100} crystal desirable for magnetic properties develops in the finish annealing. Particularly, when the average crystal grain size of the steel strip is 0.10 mm or more, excellent magnetic properties are obtained. Easy to obtain characteristics. Therefore, the average grain size of the steel strip is set to 0.10 mm or more. The average crystal grain size of the steel strip is adjusted by the temperature difference between the two surfaces of the slab during casting, the average cooling rate in the temperature range of 700° C. or higher, the hot rolling start temperature, the winding temperature, and the like. be able to. When the temperature difference between the two surfaces of the slab during casting is 40° C. or higher and the average cooling rate at 700° C. or higher is 10° C./min or less, the average grain size of the columnar crystals contained in the steel strip. Of 0.10 mm or more is obtained. Furthermore, when the starting temperature of hot rolling is 900° C. or lower and the coiling temperature is 650° C. or lower, the crystal grains contained in the steel strip are unrecrystallized stretched grains, so that the average crystal grain size is 0.10 mm. The above steel strip is obtained. The average cooling rate in the temperature range of 700°C or higher is the average cooling rate in the temperature range from the casting start temperature to 700°C, and the difference between the casting start temperature and 700°C is the casting start temperature. It is the value divided by the time required to cool from 1 to 700°C.
[0029]
　Coarse precipitate forming elements are put in the bottom of the last pot before casting in the steel making process, molten steel containing elements other than the coarse precipitate forming elements is injected into the pan, and coarse precipitate forming is generated in the molten steel. It is preferable to dissolve the element. This makes it possible to prevent the coarse precipitate-forming element from scattering from the molten steel, and also to promote the reaction between the coarse precipitate-forming element and S. The last pot before casting in the steelmaking process is, for example, the pot directly above the tundish of the continuous casting machine.
[0030]
　When the reduction ratio of cold rolling is more than 90%, a texture that inhibits the improvement of magnetic properties, for example, {111}<112> texture, is likely to develop during finish annealing. Therefore, the reduction ratio of cold rolling is 90% or less. When the reduction ratio of cold rolling is less than 40%, it may be difficult to secure the thickness accuracy and flatness of the non-oriented electrical steel sheet. Therefore, the reduction ratio of cold rolling is preferably 40% or more.
[0031]
　The finish annealing causes primary recrystallization and the growth of crystal grains, and the average crystal grain size is set to 50 μm to 180 μm. By this finish annealing, a texture in which {100} crystals are developed, which is suitable for uniformly improving the magnetic properties in all directions in the plate surface, can be obtained. In the finish annealing, for example, the holding temperature is 750° C. or higher and 950° C. or lower, and the holding time is 10 seconds or longer and 60 seconds or shorter.
[0032]
　When the sheet tension for finish annealing exceeds 3 MPa, elastic strain having anisotropy may easily remain in the non-oriented electrical steel sheet. Since elastic strain having anisotropy deforms the texture, even if a texture with developed {100} crystals is obtained, the texture is deformed and the uniformity of magnetic properties in the plane of the plate deteriorates. There is. Therefore, it is preferable that the plate tension for finish annealing is 3 MPa or less. Even when the cooling rate of finish annealing at 950° C. to 700° C. exceeds 1° C./sec, elastic strain having anisotropy tends to remain in the non-oriented electrical steel sheet. Therefore, the cooling rate of finish annealing at 950°C to 700°C is preferably 1°C/sec or less. Here, the cooling rate is different from the average cooling rate (a value obtained by dividing the difference between the cooling start temperature and the cooling end temperature by the time required for cooling). In consideration of the necessity to keep the cooling rate small at all times, in finish annealing, the cooling rate must always be 1° C./sec or less in the temperature range of 950° C. to 700° C.
[0033]
　In this way, the non-oriented electrical steel sheet according to this embodiment can be manufactured. After finish annealing, the insulating coating may be formed by coating and baking.
[0034]
　Next, a second manufacturing method of the non-oriented electrical steel sheet according to the embodiment will be described. In the second manufacturing method, rapid solidification of molten steel, cold rolling, finish annealing and the like are performed.
[0035]
　In the rapid solidification of molten steel, the molten steel having the above chemical composition is rapidly solidified on the surface of the moving and renewed cooling body, and the proportion of columnar crystals is 80% or more in area fraction and the average grain size is 0.10 mm or more. Get the steel strip. In the second manufacturing method, the γ→α transformation is likely to occur during cooling after the rapid solidification of the molten steel, but the crystal structure that has undergone the γ→α transformation from the columnar crystal is also regarded as the columnar crystal. By undergoing the γ→α transformation, the {100}<0vw> texture of columnar crystals is further sharpened.
[0036]
　The columnar crystals have a {100}<0vw> texture desirable for uniformly improving the magnetic properties of the non-oriented electrical steel sheet, particularly the magnetic properties in all directions in the plane of the sheet. The {100}<0vw> texture is a texture in which crystals having a {100} plane parallel to the plate surface and a rolling direction of <0vw> are developed (v and w are arbitrary real numbers ( Unless v and w are both 0)). If the proportion of columnar crystals is less than 80%, it is not possible to obtain a texture in which {100} crystals have developed by finish annealing throughout the thickness direction of the non-oriented electrical steel sheet. In that case, as described above, the {100} crystal does not develop in the central part of the plate thickness of the steel sheet, and the {111} crystal, which is unfavorable to the magnetic properties, develops. The proportion of columnar crystals in the steel strip is set to 80% or more in order to form a texture in which {100} crystals have developed to the center of the plate thickness. The proportion of columnar crystals in the steel strip can be specified by microscopic observation as described above.
　In the second manufacturing method, in order to set the columnar crystal ratio to 80% or more, for example, the temperature of the molten steel to be injected into the surface of the cooling body for moving and renewing is increased by 25° C. or more above the solidification temperature. In particular, when the temperature of the molten steel is raised by 40° C. or more above the solidification temperature, the proportion of columnar crystals can be made almost 100%. When the molten steel is solidified under such a condition that the proportion of such columnar crystals is 80% or more, Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn, or a sulfide or oxysulfide of Cd, or these Both are easily formed, and the formation of fine sulfides such as MnS is suppressed.
[0037]
　The smaller the average grain size of the steel strip, the larger the number of grains and the larger the area of ​​grain boundaries. In the recrystallization of finish annealing, the crystal grows from within the crystal grain and from the crystal grain boundary. The crystal growing from within the crystal grain is a {100} crystal which is desirable for magnetic properties, whereas the crystal growing from the crystal grain boundary. Is a crystal such as a {111}<112> crystal which is not desirable for magnetic properties. Therefore, the larger the average crystal grain size of the steel strip, the more easily the {100} crystal desirable for magnetic properties develops in the finish annealing. Particularly, when the average crystal grain size of the steel strip is 0.10 mm or more, excellent magnetic properties are obtained. Easy to obtain characteristics. Therefore, the average grain size of the steel strip is set to 0.10 mm or more. The average crystal grain size of the steel strip can be adjusted by the average cooling rate from completion of solidification to winding during rapid solidification. Specifically, the average cooling rate from the completion of solidification of the molten steel to the winding of the steel strip is 1,000 to 3,000° C./min.
[0038]
　During rapid solidification, coarse precipitate-forming elements are placed in the bottom of the last pot before casting in the steelmaking process, molten steel containing elements other than the coarse precipitate-forming elements is injected into the pot, It is preferable to dissolve the coarse precipitate forming element. This makes it possible to prevent the coarse precipitate-forming element from scattering from the molten steel, and also to promote the reaction between the coarse precipitate-forming element and S. The last pot before casting in the steelmaking process is, for example, the pot immediately above the tundish of a casting machine for rapid solidification.
[0039]
　When the reduction ratio of cold rolling is more than 90%, a texture that inhibits the improvement of magnetic properties, for example, {111}<112> texture, is likely to develop during finish annealing. Therefore, the reduction ratio of cold rolling is 90% or less. When the reduction ratio of cold rolling is less than 40%, it may be difficult to secure the thickness accuracy and flatness of the non-oriented electrical steel sheet. Therefore, the reduction ratio of cold rolling is preferably 40% or more.
[0040]
　The finish annealing causes primary recrystallization and the growth of crystal grains, and the average crystal grain size is set to 50 μm to 180 μm. By this finish annealing, a texture in which {100} crystals are developed, which is suitable for uniformly improving the magnetic properties in all directions in the plate surface, can be obtained. In the finish annealing, for example, the holding temperature is 750° C. or higher and 950° C. or lower, and the holding time is 10 seconds or longer and 60 seconds or shorter.
[0041]
　When the sheet tension for finish annealing exceeds 3 MPa, elastic strain having anisotropy may easily remain in the non-oriented electrical steel sheet. Since elastic strain having anisotropy deforms the texture, even if a texture with developed {100} crystals is obtained, the texture is deformed and the uniformity of magnetic properties in the plane of the plate deteriorates. There is. Therefore, it is preferable that the plate tension for finish annealing is 3 MPa or less. Even when the cooling rate of the finish annealing at 950° C. to 700° C. exceeds 1° C./sec, elastic strain having anisotropy may easily remain in the non-oriented electrical steel sheet. Therefore, the cooling rate of finish annealing at 950°C to 700°C is preferably 1°C/sec or less. Here, the cooling rate is a concept different from the average cooling rate (a value obtained by dividing the difference between the cooling start temperature and the cooling end temperature by the time required for cooling). In consideration of the necessity to keep the cooling rate small at all times, in finish annealing, the cooling rate must always be 1° C./sec or less in the temperature range of 950° C. to 700° C.
[0042]
　In this way, the non-oriented electrical steel sheet according to this embodiment can be manufactured. After finish annealing, the insulating coating may be formed by coating and baking.
[0043]
　When the thickness of the non-oriented electrical steel sheet according to the present embodiment is 0.50 mm, for example, the magnetic flux density B50 L in the rolling direction (L direction) is 1.79 T or more, the rolling direction and the width direction (C). Direction) magnetic flux density B50 average value B50 L+C : 1.75 T or more, iron loss W15/50 L in rolling direction: 4.5 W/kg or less, average value W15/50 of iron loss W15/50 in rolling direction and width direction 50 L+C : High magnetic flux density of 5.0 W/kg or less and low iron loss magnetic properties.
[0044]
　The preferred embodiment of the present invention has been described above in detail, but the present invention is not limited to this example. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in claims. It is understood that these also belong to the technical scope of the present invention.
Example
[0045]
　Next, the non-oriented electrical steel sheet according to the embodiment of the present invention will be specifically described with reference to examples. The examples described below are merely examples of the non-oriented electrical steel sheet according to the embodiment of the present invention, and the non-oriented electrical steel sheet according to the present invention is not limited to the following examples.
[0046]
　(First Test) In
　the first test, molten steel having the chemical composition shown in Table 1 was cast to produce a slab, and the slab was hot-rolled to obtain a steel strip. The blank column in Table 1 indicates that the content of the element was below the detection limit, and the balance is Fe and impurities. The underline in Table 1 indicates that the value is out of the range of the present invention. Then, the steel strip was cold-rolled and finish-annealed to produce various non-oriented electrical steel sheets having a thickness of 0.50 mm. Then, the strength of the crystal orientation in the plate thickness central portion of each non-oriented electrical steel sheet was measured, and the parameter R in the plate thickness central portion was calculated. The results are shown in Table 2. The underline in Table 2 indicates that the value is out of the range of the present invention.
[0047]
[table 1]

[0048]
[Table 2]

[0049]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 3. The underline in Table 3 indicates that the value is not in the desired range. That is, the underline of the magnetic flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the underline of the iron loss W15/50 L column indicates Indicates that it is over 4.5 W/kg, and the underline in the column of the average value W15/50 L+C indicates that it is over 5.0 W/kg.
[0050]
[Table 3]

[0051]
　As shown in Table 3, the sample No. 11-No. In No. 22, since the chemical composition is within the range of the present invention and the parameter R in the central portion of the plate thickness is within the range of the present invention, good magnetic properties were obtained.
[0052]
　Sample No. 1 to No. In Example 6, since the parameter R in the central portion of the plate thickness was too small, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In No. 7, since the S content was too high, the ratio of the total mass of S contained in the sulfide or oxysulfide of the coarse precipitate forming element to the total mass of S contained in the non-oriented electrical steel sheet (in Table 3, “S mass ratio”) was less than 40%, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In No. 8, since the total content of coarse precipitate-forming elements was too low, the total mass of S contained in the sulfides or oxysulfides of the coarse precipitate-forming elements was the total mass of S contained in the non-oriented electrical steel sheet. Is less than 40%, the iron loss W15/50 L and the average value W15/50 L+C are large, and the magnetic flux density B50 L and the average value B50 L+C are large. Was low. Sample No. In No. 9, since the total content of coarse precipitate-forming elements was too high, the total mass of S contained in the sulfide or oxysulfide of the coarse precipitate-forming element, the total mass of S contained in the non-oriented electrical steel sheet. Was 40% or more, but Ca formed many inclusions such as CaO, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. It was Sample No. In 10, the magnetic flux density B50 L and the average value B50 L+C were low because the parameter Q was too large .
[0053]
　(Second test) In
　the second test, C: 0.0023%, Si: 0.81%, Al: 0.03%, Mn: 0.20%, S: 0.0003% in mass%. And Pr: 0.0034%, with the balance being cast of molten steel consisting of Fe and impurities to produce a slab, which was hot-rolled to obtain a steel strip with a thickness of 2.1 mm. .. During casting, the temperature difference between the two surfaces of the slab was adjusted to change the proportion of columnar crystals and the average crystal grain size of the steel strip. Table 4 shows the temperature difference between the two surfaces, the proportion of columnar crystals, and the average crystal grain size. Then, cold rolling was performed at a rolling reduction of 78.2% to obtain a steel plate having a thickness of 0.50 mm. Then, continuous finish annealing was performed at 850° C. for 30 seconds to obtain a non-oriented electrical steel sheet. Then, the strengths of the eight crystal orientations of the respective non-oriented electrical steel sheets were measured, and the parameter R at the center portion of the sheet thickness was calculated. The results are also shown in Table 4. The underline in Table 4 indicates that the value is out of the range of the present invention.
[0054]
[Table 4]

[0055]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 5. The underline in Table 5 indicates that the value is not in the desired range. That is, the underline of the magnetic flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the underline of the iron loss W15/50 L column indicates Indicates that it is over 4.5 W/kg, and the underline in the column of the average value W15/50 L+C indicates that it is over 5.0 W/kg.
[0056]
[Table 5]

[0057]
　As shown in Table 5, Sample No. using a steel strip having an appropriate proportion of columnar crystals. In No. 33, since the parameter R in the central portion of the plate thickness is within the range of the present invention, good magnetic characteristics were obtained.
[0058]
　Sample No. using a steel strip having a too low columnar crystal ratio. 31 and No. In No. 32, the parameter R in the central portion of the plate thickness is out of the range of the present invention, so the iron loss W15/50 L and the average value W15/50 L+C are large, and the magnetic flux density B50 L and the average value B50 L+C are low.
[0059]
　(Third test) In
　the third test, molten steel having the chemical composition shown in Table 6 was cast to produce a slab, and the slab was hot-rolled to obtain a steel strip having a thickness of 2.4 mm. Obtained. The balance is Fe and impurities, and the underline in Table 6 indicates that the value is out of the range of the present invention. During casting, the proportion of columnar crystals and the average crystal grain size of the steel strip were changed by adjusting the temperature difference between the two surfaces of the slab and the average cooling rate at 700°C or higher. The temperature difference between the two surfaces was 48°C to 60°C. Sample No. 41 and No. 41. 42, the average cooling rate at 700° C. or higher was 20° C./minute, and the sample No. 43-No. In No. 45, the average cooling rate at 700° C. or higher was 10° C./minute or less. Table 7 shows the proportion of columnar crystals and the average crystal grain size. Then, cold rolling was performed at a reduction rate of 79.2% to obtain a steel plate having a thickness of 0.50 mm. Then, continuous finishing annealing was performed at 880° C. for 45 seconds to obtain a non-oriented electrical steel sheet. Then, the strengths of the eight crystal orientations of the respective non-oriented electrical steel sheets were measured, and the parameter R at the center portion of the sheet thickness was calculated. The results are also shown in Table 7. The underline in Table 7 indicates that the value is out of the range of the present invention.
[0060]
[Table 6]

[0061]
[Table 7]

[0062]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 8. The underline in Table 8 indicates that the value is not in the desired range. That is, the underline of the iron flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the iron loss W15/50 L column indicates The underline shows that it is more than 4.5 W/kg, and the underline of the column of the average value W15/50 L+C shows that it is more than 5.0 W/kg.
[0063]
[Table 8]

[0064]
　As shown in Table 8, sample No. using a steel strip having an appropriate chemical composition, columnar crystal ratio, and average crystal grain size was used. In No. 44, since the parameter R in the central part of the plate thickness is within the range of the present invention, good magnetic characteristics were obtained.
[0065]
　Sample No. using a steel strip having an average grain size that is too low. 41 and No. 41. In No. 42, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In No. 43, since the total content of coarse precipitate forming elements was too low, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In No. 45, since the total content of coarse precipitate-forming elements was too high, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low.
[0066]
　(Fourth Test) In
　the fourth test, molten steel having the chemical composition shown in Table 9 is cast to produce a slab, and the slab is hot-rolled to obtain a steel strip having a thickness shown in Table 10. Obtained. The blank column in Table 9 indicates that the content of the element was below the detection limit, and the balance is Fe and impurities. During casting, the temperature difference between the two surfaces of the slab was adjusted to change the proportion of columnar crystals and the average crystal grain size of the steel strip. The temperature difference between the two surfaces was 51°C to 68°C. Table 10 also shows the proportion of columnar crystals and the average crystal grain size. Then, cold rolling was performed at a rolling reduction shown in Table 10 to obtain a steel plate having a thickness of 0.50 mm. After that, continuous finish annealing was performed at 830° C. for 40 seconds to obtain a non-oriented electrical steel sheet. Then, the strengths of the eight crystal orientations of the respective non-oriented electrical steel sheets were measured, and the parameter R at the center portion of the sheet thickness was calculated. The results are also shown in Table 10. The underline in Table 10 indicates that the value is out of the range of the present invention.
[0067]
[Table 9]

[0068]
[Table 10]

[0069]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 11. The underline in Table 11 indicates that the value is not in the desired range. That is, the underline of the magnetic flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the underline of the iron loss W15/50 L column indicates Indicates that it is over 4.5 W/kg, and the underline in the column of the average value W15/50 L+C indicates that it is over 5.0 W/kg.
[0070]
[Table 11]

[0071]
　As shown in Table 11, Sample No. which was cold-rolled with an appropriate reduction amount using a steel strip having an appropriate chemical composition, columnar crystal ratio and average crystal grain size was used. 51-No. In No. 55, the parameter R in the center portion of the plate thickness is within the range of the present invention, so that good magnetic characteristics were obtained. Sample No. containing an appropriate amount of Sn or Cu. 53 and No. 53. At 54, particularly excellent iron loss W15/50 L , average value W15/50 L+C , magnetic flux density B50 L, and average value B50 L+C were obtained. Sample No. containing a proper amount of Sn and Cu. At 55, more excellent iron loss W15/50 L , average value W15/50 L+C , magnetic flux density B50 L, and average value B50 L+C were obtained.
[0072]
　Specimen No. with the cold rolling reduction too high. In No. 56, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low.
[0073]
　(Fifth Test) In
　the fifth test, C: 0.0014%, Si: 0.34%, Al: 0.48%, Mn: 1.42%, S: 0.0017% in mass%. And Sr: 0.0038%, with the balance being cast of molten steel consisting of Fe and impurities to form a slab, which was hot-rolled to obtain a steel strip having a thickness of 2.3 mm. .. During casting, the temperature difference between the two surfaces of the slab was set to 59° C., the proportion of columnar crystals in the steel strip was 90%, and the average crystal grain size was 0.17 mm. Then, cold rolling was performed at a rolling reduction of 78.3% to obtain a steel plate having a thickness of 0.50 mm. After that, continuous finish annealing was performed at 920° C. for 20 seconds to obtain a non-oriented electrical steel sheet. In finish annealing, the strip tension and the cooling rate from 950°C to 700°C were changed. Table 12 shows the strip tension and the cooling rate. Then, the strength of the crystal orientation of each non-oriented electrical steel sheet was measured, and the parameter R in the central portion of the sheet thickness was calculated. The results are also shown in Table 12.
[0074]
[Table 12]

[0075]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 13.
[0076]
[Table 13]

[0077]
　As shown in Table 13, the sample No. 61-No. In No. 64, the chemical composition was within the range of the present invention, and the parameter R in the central portion of the plate thickness was within the range of the present invention, so good magnetic properties were obtained. Sample No. in which the threading tension was 3 MPa or less. 62 and No. 62. In No. 63, elastic strain anisotropy was low, and particularly excellent iron loss W15/50 L , average value W15/50 L+C , magnetic flux density B50 L and average value B50 L+C were obtained. Sample No. 1 in which the cooling rate from 920° C. to 700° C. was 1° C./second or less. In No. 64, the elastic strain anisotropy was further low, and further excellent iron loss W15/50 L , average value W15/50 L+C , magnetic flux density B50 L and average value B50 L+C were obtained. In the measurement of elastic strain anisotropy, each side has a length of 55 mm, two sides are parallel to the rolling direction, and two sides are parallel to the direction perpendicular to the rolling direction (plate width direction). A rectangular sample was cut out from each non-oriented electrical steel sheet, and the length of each side after deformation due to the effect of elastic strain was measured. Then, it was determined how much the length in the direction perpendicular to the rolling direction was larger than the length in the rolling direction.
[0078]
　(Sixth Test) In
　the sixth test, molten steel having the chemical composition shown in Table 14 was rapidly solidified by the twin roll method to obtain a steel strip. The blank column in Table 14 indicates that the content of the element was below the detection limit, and the balance is Fe and impurities. The underline in Table 14 indicates that the value is out of the range of the present invention. Then, the steel strip was cold-rolled and finish-annealed to produce various non-oriented electrical steel sheets having a thickness of 0.50 mm. Then, the strengths of the eight crystal orientations of the respective non-oriented electrical steel sheets were measured, and the parameter R at the center portion of the sheet thickness was calculated. The results are shown in Table 15. The underline in Table 15 indicates that the value is out of the range of the present invention.
[0079]
[Table 14]

[0080]
[Table 15]

[0081]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 16. The underline in Table 16 indicates that the number is not in the desired range. That is, the underline of the magnetic flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the underline of the iron loss W15/50 L column indicates Indicates that it is over 4.5 W/kg, and the underline in the column of the average value W10/15 L+C indicates over 5.0 W/kg.
[0082]
[Table 16]

[0083]
　As shown in Table 16, the sample No. 111-No. In 120, the chemical composition was within the range of the present invention, and the parameter R in the central portion of the plate thickness was within the range of the present invention, so good magnetic properties were obtained.
[0084]
　Sample No. 101-No. In No. 106, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low, because the parameter R in the center part of the plate thickness was too small . Sample No. In 107, since the S content was too high, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In No. 108, the total content of coarse precipitate forming elements was too low, so the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In No. 109, since the total content of coarse precipitate-forming elements was too high, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were large. Was low. Sample No. At 110, the magnetic flux density B50 L and the average value B50 L+C were low because the parameter Q was too large .
[0085]
　(Seventh Test) In
　the seventh test, mass% is C: 0.0023%, Si: 0.81%, Al: 0.03%, Mn: 0.20%, S: 0.0003%. And Nd: 0.0034% and the balance of Fe and impurities was rapidly solidified by the twin roll method to obtain a steel strip having a thickness of 2.1 mm. At this time, the injection temperature was adjusted to change the proportion of columnar crystals in the steel strip and the average crystal grain size. Table 17 shows the difference between the injection temperature and the solidification temperature, the proportion of columnar crystals, and the average crystal grain size. Then, cold rolling was performed at a rolling reduction of 78.2% to obtain a steel plate having a thickness of 0.50 mm. Then, continuous finish annealing was performed at 850° C. for 30 seconds to obtain a non-oriented electrical steel sheet. Then, the strengths of the eight crystal orientations of the respective non-oriented electrical steel sheets were measured, and the parameter R at the center portion of the sheet thickness was calculated. The results are also shown in Table 17. The underline in Table 17 indicates that the numerical value is outside the range of the present invention.
[0086]
[Table 17]

[0087]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 18. The underline in Table 18 indicates that the number is not in the desired range. That is, the underline of the magnetic flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the underline of the iron loss W15/50 L column indicates Indicates that it is over 4.5 W/kg, and the underline in the column of the average value W15/50 L+C indicates that it is over 5.0 W/kg.
[0088]
[Table 18]

[0089]
　As shown in Table 18, the sample No. using a steel strip having an appropriate columnar crystal ratio was used. In No. 133, since the parameter R in the central portion of the plate thickness is within the range of the present invention, good magnetic characteristics were obtained.
[0090]
　Sample No. using a steel strip having a too low columnar crystal ratio. 131 and No. In 132, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low.
[0091]
　(Eighth Test) In
　the eighth test, molten steel having the chemical composition shown in Table 19 was rapidly solidified by the twin roll method to obtain a steel strip having a thickness of 2.4 mm. The balance is Fe and impurities, and the underline in Table 19 indicates that the value is out of the range of the present invention. At this time, the injection temperature and the average cooling rate from the completion of solidification of the molten steel to the winding of the steel strip were adjusted to change the proportion of columnar crystals and the average grain size of the steel strip. The injection temperature of Examples 143 to 145 was higher than the solidification temperature by 29 to 35° C., and the average cooling rate from the completion of solidification of the molten steel to the winding of the steel strip was 1,500 to 2,000° C./minute. The injection temperature in Examples 141 and 142 was 20 to 24° C. higher than the solidification temperature, and the average cooling rate from completion of solidification of molten steel to winding of the steel strip was more than 3,000° C./min. Table 20 shows the proportion of columnar crystals and the average crystal grain size. Then, cold rolling was performed at a reduction rate of 79.2% to obtain a steel plate having a thickness of 0.50 mm. Then, continuous finishing annealing was performed at 880° C. for 45 seconds to obtain a non-oriented electrical steel sheet. Then, the strengths of the eight crystal orientations of the respective non-oriented electrical steel sheets were measured, and the parameter R at the center portion of the sheet thickness was calculated. The results are also shown in Table 20. The underline in Table 20 indicates that the value is out of the range of the present invention.
[0092]
[Table 19]

[0093]
[Table 20]

[0094]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 21. The underline in Table 21 indicates that the value is not in the desired range. That is, the underline of the iron flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the iron loss W15/50 L column indicates The underline shows that it is more than 4.5 W/kg, and the underline of the column of the average value W15/50 L+C shows that it is more than 5.0 W/kg.
[0095]
[Table 21]

[0096]
　As shown in Table 21, Sample No. using a steel strip having an appropriate chemical composition, columnar crystal ratio, and average crystal grain size was used. In 144, since the parameter R in the central portion of the plate thickness is within the range of the present invention, good magnetic characteristics were obtained.
[0097]
　Sample No. using a steel strip having an average grain size that is too low. 141 and No. In 142, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In 143, since the total content of coarse precipitate-forming elements was too low, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low. Sample No. In 145, since the total content of coarse precipitate forming elements was too high, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low.
[0098]
　(Ninth Test) In
　the ninth test, molten steel having the chemical composition shown in Table 22 was rapidly solidified by the twin roll method to obtain a steel strip having a thickness shown in Table 23. The blank column in Table 22 indicates that the content of the element is below the detection limit, and the balance is Fe and impurities. At this time, the injection temperature was adjusted to change the proportion of columnar crystals in the steel strip and the average crystal grain size. The injection temperature was 28°C to 37°C higher than the solidification temperature. Table 23 also shows the proportion of columnar crystals and the average crystal grain size. Then, cold rolling was performed at a rolling reduction shown in Table 23 to obtain a steel plate having a thickness of 0.20 mm. After that, continuous finish annealing was performed at 830° C. for 40 seconds to obtain a non-oriented electrical steel sheet. Then, the strengths of the eight crystal orientations of the respective non-oriented electrical steel sheets were measured, and the parameter R at the center portion of the sheet thickness was calculated. The results are also shown in Table 23. The underline in Table 23 shows that the numerical value is outside the scope of the present invention.
[0099]
[Table 22]

[0100]
[Table 23]

[0101]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 24. The underline in Table 24 indicates that the number is not in the desired range. That is, the underline of the magnetic flux density B50 L column indicates less than 1.79 T, the underline of the average value B50 L+C column indicates less than 1.75 T, and the underline of the iron loss W15/50 L column indicates Indicates that it is over 4.5 W/kg, and the underline in the column of the average value W15/50 L+C indicates that it is over 5.0 W/kg.
[0102]
[Table 24]

[0103]
　As shown in Table 24, using a steel strip having an appropriate chemical composition, a ratio of columnar crystals, and an average grain size, cold rolling was performed with an appropriate reduction amount. 151-No. In No. 154, the parameter R in the central portion of the plate thickness was within the range of the present invention, so that good magnetic characteristics were obtained. Sample No. containing an appropriate amount of Sn or Cu. 153 and No. 153. At 154, particularly excellent iron loss W15/50 L , average value W15/50 L+C , magnetic flux density B50 L, and average value B50 L+C were obtained.
[0104]
　Specimen No. with the cold rolling reduction too high. At 155, the iron loss W15/50 L and the average value W15/50 L+C were large, and the magnetic flux density B50 L and the average value B50 L+C were low.
[0105]
　(Tenth Test) In
　the tenth test, C: 0.0014%, Si: 0.34%, Al: 0.48%, Mn: 1.42%, S: 0.0017% in mass%. And Sr: 0.0038% and the balance of Fe and impurities was rapidly solidified by a twin roll method to obtain a steel strip having a thickness of 2.3 mm. At this time, the injection temperature was set to be 32° C. higher than the solidification temperature so that the proportion of columnar crystals in the steel strip was 90% and the average crystal grain size was 0.17 mm. Then, cold rolling was performed at a rolling reduction of 78.3% to obtain a steel plate having a thickness of 0.50 mm. After that, continuous finish annealing was performed at 920° C. for 20 seconds to obtain a non-oriented electrical steel sheet. In the finish annealing, the strip tension and the cooling rate from 920°C to 700°C were changed. Table 25 shows the strip tension and the cooling rate. Then, the strength of the crystal orientation of each non-oriented electrical steel sheet was measured, and the parameter R in the central portion of the sheet thickness was calculated. The results are also shown in Table 25.
[0106]
[Table 25]

[0107]
　And the magnetic characteristic of each non-oriented electrical steel sheet was measured. The results are shown in Table 26.
[0108]
[Table 26]

[0109]
　As shown in Table 26, sample No. 161-No. In No. 164, the chemical composition was within the range of the present invention, and the parameter R in the central portion of the plate thickness was within the range of the present invention, so good magnetic properties were obtained. Sample No. in which the threading tension was 3 MPa or less. 162 and No. 162. In No. 163, elastic strain anisotropy was low, and particularly excellent iron loss W15/50 L , average value W15/50 L+C , magnetic flux density B50 L and average value B50 L+C were obtained. Sample No. 1 in which the cooling rate from 920° C. to 700° C. was 1° C./second or less. In No. 164, the elastic strain anisotropy was further low, and further excellent iron loss W15/50 L , average value W15/50 L+C , magnetic flux density B50 L and average value B50 L+C were obtained. In addition, in the measurement of elastic strain anisotropy, a plane shape in which each side has a length of 55 mm, two sides are parallel to the rolling direction, and two sides are parallel to a direction perpendicular to the rolling direction (sheet width direction) A quadrangular sample was cut out from each non-oriented electrical steel sheet, and the length of each side after deformation due to the influence of elastic strain was measured. Then, it was determined how much the length in the direction perpendicular to the rolling direction was larger than the length in the rolling direction.
Industrial availability
[0110]
　INDUSTRIAL APPLICABILITY The present invention can be used in, for example, a manufacturing industry of non-oriented electrical steel sheets and an industry of utilizing non-oriented electrical steel sheets.
The scope of the claims
[Claim 1]
　In mass %,
　C: 0.0030% or less,
　Si: 2.00% or less,
　Al: 1.00% or less,
　Mn: 0.10% to 2.00%,
　S: 0.0030% or less,
　Mg, One or more selected from the group consisting of Ca, Sr, Ba, Nd, Pr, La, Ce, Zn and Cd: 0.0015% to 0.0100% in total,
　Si content (mass%) is [Si] , Al content (mass %) is defined as [Al], Mn content (mass %) is defined as [Mn], and the parameter Q represented by the formula 1 is 2.00 or less,
　Sn: 0.00% to 0. .40%,
　Cu: 0.00% to 1.00%, and the
　balance: Fe and impurities,
　with a chemical composition represented by
　{100} crystal orientation strength and {310} crystal orientation in the center of the plate thickness. Strength, {411} crystal orientation strength, {521} crystal orientation strength, {111} crystal orientation strength, {211} crystal orientation strength, {332} crystal orientation strength, and {221} crystal orientation strength are I 100 and I 310 , respectively. , I 411 , I 521 , I 111 , I 211, I 332 , I 221 and the parameter R represented by the formula 2 is 0.80 or more, a non-oriented electrical steel sheet.
　Q=[Si]+2×[Al]−[Mn] (Equation 1)
　R=(I 100 +I 310 +I 411 +I 521 )/(I 111 +I 211 +I 332 +I 221 ) (Equation 2)
[Claim 2]
　The non-directional material according to claim 1, 　wherein
　Sn: 0.02% to 0.40%,
　Cu: 0.10% to 1.00%,
or both are satisfied in the chemical composition. Magnetic electrical steel sheet.
[Claim 3]
　It is a manufacturing method of the non-oriented electrical steel sheet of Claim 1 or 2,
　Comprising: The continuous casting process of molten
　steel, the hot rolling process of the steel ingot obtained by the said continuous casting process, and the
　said hot rolling process. It
　comprises a cold rolling step of the obtained steel strip and a finish annealing step of the cold rolled steel sheet obtained by the cold rolling step,
　wherein the molten steel has the chemical composition according to claim 1 or 2. ,
　the steel strip, the proportion of the columnar crystals are in an area fraction of 80% or higher and the average crystal grain size is more than 0.10 mm,
　the rolling reduction in the cold rolling step is 90% or less
, wherein the And a method for manufacturing a non-oriented electrical steel sheet.
[Claim 4]
　The method for producing a non-oriented electrical steel sheet according to claim 3, wherein in the continuous casting step, the temperature difference between the one surface and the other surface of the steel ingot during solidification is set to 40°C or more.
[Claim 5]
　In the hot rolling step, the starting temperature of hot rolling is set to 900° C. or lower, and the coiling temperature of the steel strip is set to 650° C. or lower, and the nondirectional electromagnetic according to claim 3 or 4. Steel plate manufacturing method.
[Claim 6]

The non-directional property according to any one of claims 3 to 5, 　wherein the thread tension in the finish annealing step is 3 MPa or less and the cooling rate at 950°C to 700°C is 1°C/sec or less . Manufacturing method of electrical steel sheet.
[Claim 7]
　It is a manufacturing method of the non-oriented electrical steel sheet of Claim 1 or 2,
　Comprising: The rapid solidification process of molten
　steel, the cold rolling process of the steel strip obtained by the said rapid solidification process, and the
　said cold rolling process. And a finish annealing step of the obtained cold rolled steel sheet,
　wherein the molten steel has the chemical composition according to claim 1 or 2, and the
　steel strip has a columnar crystal ratio of 80% or more in area fraction. A method for producing a non-oriented electrical steel sheet ,
　wherein the average grain size is 0.10 mm or more, and the rolling reduction in the cold rolling step is 90% or less
.
[Claim 8]
　Wherein in the rapid solidification process, using a cooling body moving updated solidifying the molten steel,
　the temperature of the molten steel is injected into the cooling body to the moving update, high 25 ° C. or higher than the solidification temperature of the molten steel
characterized in that The method for manufacturing a non-oriented electrical steel sheet according to claim 7.
[Claim 9]
　In the rapid solidification step, the molten steel is solidified using a moving and renewing cooling body, and
　an average cooling rate from completion of solidification of the molten steel to winding of the steel strip is 1,000 to 3,000° C./min. The method for producing a non-oriented electrical steel sheet according to claim 7 or 8, characterized in that.
[Claim 10]

The non-directional property according to any one of claims 7 to 9, 　wherein the strip tension in the finish annealing step is 3 MPa or less and the cooling rate at 950°C to 700°C is 1°C/sec or less . Manufacturing method of electrical steel sheet.