The present invention relates to a non-oriented electrical steel sheet, a split type stator, and a rotary electric machine including the split type stator. This application claims priority based on Japanese Patent Application No. 2019-006447 filed in Japan on January 17, 2019, and the contents thereof are incorporated herein by reference. Background technology [0002] As a rotary electric machine such as an electric motor and a generator, a configuration including a stator and a rotor provided on the inner peripheral side of the stator is known. Non-oriented electrical steel sheets are often used as the material for the stator and rotor. When the stator is manufactured integrally, a decrease in yield becomes a problem. Therefore, a split type stator in which a plurality of stator pieces are arranged side by side in the circumferential direction is often used (for example, Patent Document 1). reference). [0003] In recent years, global environmental problems have been attracting attention, and the demand for energy conservation efforts is increasing. In particular, there is a strong demand for higher efficiency of electrical equipment, and this tendency is remarkable in drive motors for electric vehicles and hybrid vehicles and compressor motors for air conditioners. [0004] To improve the efficiency of electrical equipment, it is effective to improve the magnetic properties of non-oriented electrical steel sheets used in motors included in electrical equipment. Therefore, in response to such a problem, for example, Patent Document 2 discloses a non-oriented electrical steel sheet having dramatically improved magnetic properties in the rolling direction. [0005] According to Patent Document 2, it is possible to dramatically improve the magnetic properties in the rolling direction by performing skin pass and strain relief annealing at a predetermined rolling ratio after finish annealing. However, as a result of studies by the present inventors, in a steel sheet containing 2.5% or more of Si, even if the technique described in Patent Document 2 is adopted, the magnetic properties in the rolling direction are improved. I found that it may not be possible to make it. [0006] In addition, the split type stator is manufactured by processing non-oriented electrical steel sheets by punching or cutting. Therefore, the non-oriented electrical steel sheet used for the split type stator is required to have workability, machinability and the like. However, when the magnetic properties of the non-oriented electrical steel sheet in the rolling direction are improved as in Patent Document 2, anisotropy exists in the structure and the workability may be deteriorated. In addition, when using the split type stator as described above, it is necessary to fix a plurality of stator pieces from the outer peripheral side by shrink fitting or the like in a ring-shaped case. Therefore, a compressive stress in the circumferential direction is applied between the divided adjacent stator pieces. Such compressive stress in the circumferential direction causes deformation of the split type stator, which may reduce dimensional accuracy. However, Patent Document 2 does not consider such a problem. Prior art literature Patent documents [0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-193695 Patent Document 2: Japanese Patent Application Laid-Open No. 2006-265720 Outline of the invention Problems to be solved by the invention [0008] The present invention has been made to solve such a problem, and is a non-oriented electrical steel sheet having excellent workability and magnetic properties after strain removal and annealing, which is suitable for a split type stator, and has excellent magnetic properties. It is an object of the present invention to provide a split-type stator having high dimensional accuracy by suppressing deformation caused by compressive stress in the circumferential direction, and a rotary electric machine provided with the split-type stator. Means to solve problems [0009] The gist of the present invention is the following non-oriented electrical steel sheets, split stators and rotary electric machines. [0010] (1) The non-oriented electrical steel sheet according to one aspect of the present invention has a chemical composition of% by mass, C: 0.0015% or less, Si: 2.5 to 4.0%, and average crystals. The particle size is 10 to 40 μm, and an internal oxide layer having a thickness of 0.5 to 3.0 μm in the plate thickness direction from the surface is present. (2) The non-oriented electrical steel sheet according to (1) has the chemical composition of mass%, C: 0.0015% or less, Si: 2.5 to 4.0%, Mn: 0.05 to. 2.0%, sol. Al: 0.0005 to 1.50%, P: 0.080% or less, S: 0.0030% or less, Ti: 0.0030% or less, Ni: 0 to 0.10%, Cu: 0 to 0. 10%, Cr: 0 to 0.10%, Sn: 0 to 0.20%, Ca: 0 to 0.0050%, Mg: 0 to 0.0050%, REM: 0 to 0.0050%, balance: It may be Fe and impurities. (3) The non-directional electromagnetic steel plate according to (1) or (2) has an EL / E c ratio, which is the ratio of the Young's modulus EL in the rolling direction to the Young's modulus E c in the direction perpendicular to the rolling direction. It may be 0.90 or more. (4) The non-oriented electrical steel sheet according to any one of (1) to (3) has a tensile strength of (230 + 100 × ([Si] + 0.5 × [sol.Al])) MPa or more and elongation. May be less than 20%. Here, [Si] is the Si content in mass% in the non-oriented electrical steel sheet, [sol. Al] is sol. Al content. (5) The split-type stator according to another aspect of the present invention is a split-type stator for a rotary electric machine, which is divided into a plurality of stator pieces in the circumferential direction, and is a cylindrical yoke extending in the axial direction. And a plurality of teeth extending in the radial direction from the inner peripheral surface of the yoke, the stator piece is formed by laminating a plurality of non-oriented electrical steel sheets, and the extending direction of the teeth is used as a reference for the crystal axis. When the above case, the X-ray random intensity ratio of the {110} <001> orientation of the stator piece is 5 or more, the average grain size of the non-oriented electrical steel sheet is 100 to 200 μm, and the non-directional electromagnetic steel sheet is 100 to 200 μm. The chemical composition of the grain-oriented electrical steel sheet contains C: 0.0015% or less and Si: 2.5 to 4.0% in mass%. (6) In the split type stator according to (5), the value of B50 / Bs of the stator piece in the direction in which the teeth extend is 0.85 or more, and Young's modulus E (GPa) in the circumferential direction of the yoke is achieved. ) May satisfy the following equation (i). E ≧ 205-3.3 × [Si] +10 ・ ・ ・ (i) However, [Si] in the above formula represents the Si content in the non-oriented electrical steel sheet in mass%. (7) In the split-type stator according to (5) or (6), the chemical composition of the non-oriented electrical steel sheet is C: 0.0015% or less in mass%, Si: 2.5 to 4 .0%, Mn: 0.05-2.0%, sol. Al: 0.0005 to 1.50%, P: 0.080% or less, S: 0.0030% or less, Ti: 0.0030% or less, Ni: 0 to 0.10%, Cu: 0 to 0. 10%, Cr: 0 to 0.10%, Sn: 0 to 0.20%, Ca: 0 to 0.0050%, Mg: 0 to 0.0050%, REM: 0 to 0.0050%, balance: It may be Fe and impurities. (8) The rotary electric machine according to another aspect of the present invention includes the split type stator according to any one of (5) to (7) and the rotor arranged on the inner peripheral side of the split type stator. A case is provided in which the stator pieces are brought into close contact with the plurality of stator pieces from the outer periphery of the yoke and the stator pieces are fixed. The invention's effect [0011] According to the above aspect of the present invention, a non-oriented electrical steel sheet having excellent workability and magnetic properties after strain removal and annealing, excellent magnetic properties, and suppressing deformation due to compressive stress in the circumferential direction to achieve high dimensional accuracy. It is possible to obtain a split-type stator having the split-type stator and a rotary electric machine including the split-type stator. A brief description of the drawing [0012] FIG. 1 is a diagram showing a configuration of a rotary electric machine according to an embodiment of the present invention. Embodiment for carrying out the invention [0013] The present inventors conducted a study to solve the above problems. As a result, the following findings were obtained. [0014] Of the stator pieces, the yoke part is subjected to compressive stress in the circumferential direction, which causes deformation. However, by using a steel plate having a dominant {110} <001> direction (also referred to as "Goss direction" in the following description), it is possible to increase the Young's modulus in the circumferential direction of the yoke, and the amount of elastic deformation can be increased. Can be mitigated. [0015] In addition, since the steel sheet having a superior Goss orientation has excellent magnetic characteristics, it is possible to improve the magnetic characteristics in the teeth portion. [0016] Here, as described above, in the non-oriented electrical steel sheet having a high Si content, the Goss orientation may not be dominant even if the skin pass is performed. Therefore, as a result of investigating the characteristics of the steel sheet manufactured under various conditions by the inventors, even when the Si content is high, decarburization occurs in the finish annealing step before the skin pass, and the C content is reduced. As a result, it was found that the Goss orientation can be stably made dominant after the strain removal annealing. [0017] The present invention has been made based on the above findings. Hereinafter, the non-oriented electrical steel sheet, the split type stator, and the rotary electric machine provided with the non-oriented electrical steel sheet according to the embodiment of the present invention will be described with reference to the drawings. [0018] 1. overall structure FIG. 1 is a diagram showing a configuration of a rotary electric machine according to an embodiment of the present invention. The rotary electric machine 100 includes a split stator 10, a rotor 20, and a case 30. [0019] The split type stator 10 is divided into a plurality of stator pieces 10a in the circumferential direction, and has a cylindrical yoke 11 extending in the axial direction and a plurality of teeth 12 extending in the radial direction from the inner peripheral surface of the yoke 11. Be prepared. In the present embodiment, a virtual circle C passing through the groove bottom 12a between the teeth 12 is defined as a boundary between the yoke 11 and the teeth 12. Further, in the present embodiment, 45 teeth are provided, but the present invention is not limited to this, and for example, 12 or 18 teeth may be provided. [0020] In the present embodiment, the split type stator 10 is divided into 45 stator pieces 10a in the circumferential direction. That is, one tooth 12 is provided for each stator piece 10a. Further, the stator pieces 10a all have the same configuration. Then, each stator piece 10a is formed, for example, by laminating a plurality of non-oriented electrical steel sheets (non-oriented electrical steel sheets according to the present embodiment) having the same shape. [0021] The rotor 20 is arranged on the inner peripheral side of the split type stator 10 so that its axis (center of rotation) coincides with the axis of the split type stator 10. Further, the case 30 is in close contact with the plurality of stator pieces 10a from the outer periphery of the yoke 11 to fix the stator pieces 10a. The case 30 is brought into close contact with the stator piece 10a by, for example, shrink fitting. At this time, a force is applied to the stator piece 10a from the outer peripheral side by the case 30. [0022] 2. Non-oriented electrical steel sheet 2-1. Chemical composition The chemical composition of the non-oriented electrical steel sheet according to the present embodiment, which is suitable for forming each stator piece, is C: 0.0015% or less and Si: 2.5 to 4.0% in mass%. , Must be contained. The reasons for each limitation will be explained. In the following description, "%" for the content means "% by mass". [0023] C: 0.0015% or less C is an element that contributes to increasing the strength of the steel sheet. However, in the present embodiment, by reducing the C content, even when the Si content is high, it is possible to stably give the Goss orientation an advantage after strain removal annealing. It is considered that when the C content is high, TiC is deposited during strain removal annealing, the grain boundary movement is temporarily pinned, and the strain required for strain-induced grain growth is lost by recovery during that time. Therefore, the C content is set to 0.0015% or less. The C content is preferably 0.0013% or less, more preferably 0.0010% or less. The lower limit of the C content is not limited, but an excessive reduction of the C content leads to an increase in manufacturing cost. Therefore, the C content is preferably 0.0001% or more, more preferably 0.0005% or more. [0024] Si: 2.5-4.0% Si is an element that increases the electrical resistance of steel and improves iron loss. In addition, Si is an element effective for increasing the strength of steel sheets because it has a large solid solution strengthening ability. Therefore, the Si content is set to 2.5% or more. The Si content is preferably 2.8% or more. On the other hand, if the Si content is excessive, the workability will be significantly deteriorated and it will be difficult to carry out cold rolling. There is it. Therefore, the Si content is set to 4.0% or less. The Si content is preferably 3.7% or less. [0025] The chemical composition other than C and Si is not particularly limited, but the chemical composition of the non-oriented electrical steel sheet according to the present embodiment is, for example, by mass%, C: 0.0015% or less, Si: 2.5. ~ 4.0%, Mn: 0.05 ~ 2.0%, sol. Al: 0.0005 to 1.50%, P: 0.080% or less, S: 0.0030% or less, Ti: 0.0030% or less, Ni: 0 to 0.10%, Cu: 0 to 0. 10%, Cr: 0 to 0.10%, Sn: 0 to 0.20%, Ca: 0 to 0.0050%, Mg: 0 to 0.0050%, REM: 0 to 0.0050%, balance: It is preferably Fe and impurities. [0026] The reasons for limiting each element are as follows. [0027] Mn: 0.05-2.0% Mn is an element that increases the electrical resistance of steel and improves iron loss. Further, when the Mn content is too low, the effect of increasing the electric resistance is small, and fine sulfide (MnS) is precipitated, which may deteriorate the grain growth property at the time of finish annealing. Therefore, the Mn content is preferably 0.05% or more. The Mn content is more preferably 0.1% or more, still more preferably 0.2% or more. On the other hand, if the Mn content is excessive, the magnetic flux density may decrease. Therefore, the Mn content is preferably 2.0% or less. The Mn content is more preferably 1.5% or less. [0028] Sol. Al: 0.0005 to 1.50% Al is an element that increases the electrical resistance of steel and improves iron loss. Therefore, the Al content is preferably 0.0005% or more, more preferably 0.15% or more. On the other hand, if the Al content is excessive, the magnetic flux density may decrease. Therefore, the Al content is preferably 1.50% or less, more preferably 1.00% or less. In this embodiment, the Al content is determined by sol. It means the content of Al (acid-soluble Al). [0029] P: 0.080% or less P is contained in steel as an impurity, and if the content is excessive, the ductility of the steel sheet may be significantly reduced. Therefore, the P content is preferably 0.080% or less. The P content is more preferably 0.050% or less. [0030] S: 0.0030% or less S is an element that increases iron loss by forming fine precipitates of MnS and deteriorates the magnetic properties of the steel sheet. Therefore, the S content is preferably 0.0030% or less. The S content is more preferably 0.0015% or less. On the other hand, since an extreme reduction in the S content may lead to an increase in manufacturing cost, the S content is preferably 0.0001% or more, more preferably 0.0003% or more, still more preferably 0.0005% or more. .. [0031] Ti: 0.0030% or less Ti is an element that is inevitably mixed and can be combined with carbon or nitrogen to form a precipitate (carbide, nitride). When carbides or nitrides are formed, these precipitates themselves may deteriorate the magnetic properties. Furthermore, the precipitate may inhibit the growth of crystal grains during finish annealing, and the magnetic properties may deteriorate. Therefore, the Ti content is preferably 0.0030% or less. The Ti content is more preferably 0.0020% or less. On the other hand, an extremely low Ti content may lead to an increase in manufacturing cost, so the Ti content is preferably 0.0005% or more. [0032] Ni: 0 to 0.10% Cu: 0 to 0.10% Cr: 0 to 0.10% Sn: 0 to 0.20% Ca: 0 to 0.0050% Mg: 0 to 0.0050% REM: 0 to 0.0050% Ni, Cu, Cr, Sn, Ca, Mg and REM are elements that can be inevitably mixed. On the other hand, since these elements are also elements that improve the magnetic properties, they may be intentionally contained. If you want to obtain the effect of improving magnetic characteristics, Ni: 0.01% or more, Cu: 0.01% or more, Cr: 0.01% or more, Sn: 0.01% or more, Ca: 0.0005% As described above, it is preferable to contain one or more selected from Mg: 0.0005% or more and REM: 0.0005% or more. [0033] However, if these elements are excessively contained, the economic efficiency may be deteriorated. Therefore, even when intentionally contained, Ni: 0.10% or less, Cu: 0.10% or less, Cr: 0.10 % Or less, Sn: 0.20% or less, Ca: 0.0050% or less, Mg: 0.0050% or less, and REM: 0.0050% or less. [0034] In the chemical composition of the non-oriented electrical steel sheet according to this embodiment, the balance is Fe and impurities. Here, the "impurity" is a component mixed with raw materials such as ore and scrap, and various factors in the manufacturing process when steel is industrially manufactured, and is used in the non-oriented electrical steel sheet according to the present embodiment. It means something that is acceptable as long as it does not have an adverse effect. [0035] 2-2. Average crystal grain size The non-oriented electrical steel sheet according to this embodiment has an average crystal grain size of 10 to 40 μm. If the average crystal grain size is less than 10 μm, the number of crystal grains having anisotropy to be coarsened may not be sufficient, which is not preferable. On the other hand, if the average crystal grain size exceeds 40 μm, the start of strain-induced grain growth is delayed, and anisotropy may not be obtained after strain removal annealing, which is not preferable. [0036] The average crystal grain size of the non-oriented electrical steel sheet according to this embodiment is measured according to JIS G 0551: 2013 "Steel-grain size microscopic test method". [0037] 2-3. Internal oxide layer In the non-oriented electrical steel sheet according to the present embodiment, an internal oxide layer having a thickness of 0.5 μm or more and 3.0 μm or less is formed in the plate thickness direction from the surface. The internal oxide layer is formed and present, which makes it easier to cut by punching or cutting, and improves the dimensional accuracy of processing. If the internal oxide layer is not formed or the thickness of the internal oxide layer is thin, the workability is deteriorated. On the other hand, if the thickness of the internal oxide layer exceeds 3.0 μm, the growth of crystal grains is hindered and the magnetic properties after strain relief annealing are deteriorated, which is not preferable. An internal oxide layer can be formed by decarburizing during finish annealing. [0038] The thickness of the internal oxide layer can be measured by polishing the cross section of the steel sheet and observing it with an SEM or the like. Since the thickness of the internal oxide layer may vary from place to place, for example, the range of 10 μm or more in the width direction in the C-direction cross section is set as one field of view, and the average value of the total thickness measured in multiple fields of view of three or more fields is taken. Is desirable. [0039] 2-4. Young's modulus anisotropy If the GOSS orientation is dominant before machining the non-oriented electrical steel sheet into the shape of the stator piece of the split type stator, Young's modulus anisotropy occurs and the roundness of the hole during punching is reduced. Workability deteriorates due to deterioration, or the dimensional accuracy and the amount of sagging during machining differ significantly between the teeth of the split type stator and the yoke direction. Therefore, it is preferable that the non-oriented electrical steel sheet does not have anisotropy at the stage of processing into a stator piece. In the non-directional electromagnetic steel plate according to the present embodiment, EL / E c, which is the ratio of Young's modulus EL in the rolling direction to Young's modulus E c in the direction perpendicular to the rolling direction, is 0.90 or more. preferable. The greater the anisotropy of Young's modulus, the lower the processability. The upper limit of EL / E c is preferably 1.0, and may be 0.95 or less. On the other hand, it is preferable that the grain-oriented electrical steel sheet changes to a structure in which the GOSS orientation is dominant at the stage of being incorporated into the split-type stator after strain removal annealing. [0040] 2-5. Mechanical properties The non-oriented electrical steel sheet according to this embodiment has a tensile strength of (230 + 100 × ([Si] +0.5 × [sol.Al])) MPa or more and an elongation (total elongation) of less than 20%. Is preferable. Due to its high strength and low elongation, it becomes a cut surface with good dimensional accuracy with less sagging during processing, and workability is improved. However, [Si] is the Si content in mass% of the non-oriented electrical steel sheet, [sol. Al] is sol. Al content. [0041] Tensile strength and elongation are measured in accordance with JIS Z2241: 2011 "Metallic Material Tensile Test Method". The shape of the test piece is not particularly limited. When sampling from non-oriented electrical steel sheets, the shape of the test piece may be, for example, JIS13B, and the test piece may be sampled so that the longitudinal direction of the test piece is parallel to the rolling direction. [0042] 3. Split stator The split-type stator 10 according to the present embodiment is a split-type stator for a rotary electric machine 100 that is divided into a plurality of stator pieces 10a in the circumferential direction, and includes a cylindrical yoke 11 extending in the axial direction. A plurality of teeth 12 extending in the radial direction from the inner peripheral surface of the yoke 11 are provided, and the stator piece 10a is formed by laminating a plurality of non-oriented electrical steel sheets, and the crystal axis extends in the extending direction of the teeth 12. The X-ray random intensity ratio of the {110} <001> orientation of the stator piece 10a is 5 or more, and the average grain size of the non-oriented electrical steel sheet is 100 to 200 μm. The chemical composition of the non-oriented electrical steel sheet contains C: 0.0015% or less and Si: 2.5 to 4.0% in mass%. The chemical composition of the non-oriented electrical steel sheet is C: 0.0015% or less, Si: 2.5 to 4.0%, Mn: 0.05 to 2.0%, sol. Al: 0.0005 to 1.50%, P: 0.080% or less, S: 0.0030% or less, Ti: 0.0030% or less, Ni: 0 to 0.10%, Cu: 0 to 0. 10%, Cr: 0 to 0.10%, Sn: 0 to 0.20%, Ca: 0 to 0.0050%, Mg: 0 to 0.0050%, REM: 0 to 0.0050%, balance: It is preferably Fe and impurities. It is preferable that the plurality of laminated non-oriented electrical steel sheets electromagnetic steel sheets are all the non-oriented electrical steel sheets according to the present embodiment described above. [0043] 3-1. anisotropy The stator piece 10a is dominant in the Goss orientation, and specifically, the X-ray random intensity ratio of the {110} <001> orientation of the stator piece 10a is 5 or more. By making the Goss orientation dominant, it is possible to improve the magnetic characteristics, increase the Young's modulus in the circumferential direction of the yoke portion, and reduce the amount of elastic deformation. The X-ray random intensity ratio of the {110} <001> orientation is preferably 8 or more. The upper limit of the X-ray random intensity ratio does not have to be limited, but 20 may be a substantial upper limit. [0044] The X-ray random intensity ratio of the {110} <001> orientation is measured by X-ray diffraction. In the measurement, the direction in which the teeth extend is used as the reference for the crystal axis. The X-ray random intensity ratio is the X-ray intensity of a standard sample that does not have accumulation in a specific orientation (for example, a sample obtained by sintering Fe powder) and a test material under the same conditions. It is a numerical value obtained by dividing the X-ray intensity of the obtained test material by the X-ray intensity of the standard sample, which was measured by an X-ray diffraction method or the like. When measuring the X-ray random intensity ratio of the stator pieces provided in the split type stator, disassemble the split type stator and take out a single non-oriented electrical steel sheet for measurement. [0045] 3-2. Average crystal grain size of non-oriented electrical steel sheets that make up the stator piece The average crystal grain size of the non-oriented electrical steel sheets constituting each stator piece is 100 to 200 μm. If the average crystal grain size is less than 100 μm, the hysteresis loss increases and the iron loss deteriorates. The average crystal grain size is more preferably 120 μm or more. On the other hand, when the average crystal grain size exceeds 200 μm, the eddy current loss increases and the iron loss deteriorates. The average crystal grain size is more preferably 170 μm or less. For the average crystal grain size of the non-oriented electrical steel sheet constituting the stator piece, the average crystal grain size is measured according to JIS G 0551: 2013 “Steel-Grade grain microscopic test method”. When measuring the average crystal grain size of the stator pieces provided in the split-type stator, disassemble the split-type stator and take out a single non-oriented electrical steel sheet for measurement. [0046] 3-3. Chemical composition of non-oriented electrical steel sheets that make up the stator piece Consists of a stator piece Since the chemical composition of grain-oriented electrical steel sheets does not change due to processing or strain removal annealing, the range and reasons for limitation are the same as those of grain-oriented electrical steel sheets used as materials. [0047] 3-4. Characteristic As described above, the Goss orientation is predominant for each stator piece constituting the split type stator according to the present embodiment. Therefore, the magnetic characteristics are excellent, and the Young's modulus E in the circumferential direction of the yoke portion is high. [0048] Specifically, it is preferable to have a magnetic property in which the value of B50 / Bs in the direction in which the teeth of the stator piece extends is 0.85 or more. Further, it is preferable that the Young's modulus E (GPa) in the circumferential direction of the yoke satisfies the following equation (i) in relation to the Si content. E ≧ 205-3.3 × [Si] +10 ・ ・ ・ (i) However, [Si] in the above formula represents the Si content (mass%) in the non-oriented electrical steel sheet constituting the stator piece. [0049] 4. Rotating machine As shown in FIG. 1, the rotary electric machine 100 according to the present embodiment includes the split type stator 10 according to the above-described present embodiment, the rotor 20 arranged on the inner peripheral side of the split type stator 10, and the rotor 20. A case 30 is provided which is in close contact with the plurality of stator pieces 10a from the outer periphery of the yoke 11 and fixes the stator pieces. This rotary electric machine has excellent Punching dimensional accuracy because the Young's modulus anisotropy during punching of non-oriented electrical steel sheets is low, and elasticity in shrink fitting due to the high Young's modulus in the yoke direction after strain removal and annealing. There is little deformation. Therefore, the dimensional accuracy as an integrated core is excellent. In addition, since the magnetic flux density in the teeth direction is high, copper loss is reduced and the motor efficiency is excellent. [0050] 6. Production method The method for manufacturing the non-oriented electrical steel sheet according to the present embodiment, the split stator according to the present embodiment, and the rotary electric machine according to the present embodiment is not particularly limited, but may be manufactured by the method shown below. It is possible. [0051] 6-1. Manufacturing method of non-oriented electrical steel sheet There are no particular restrictions on the method of manufacturing grain-oriented electrical steel sheets suitable as a material for split-type stators. For example, it can be obtained by a manufacturing method including the following steps. (I) A step of heating a slab having a predetermined chemical composition and then hot rolling to obtain a hot rolled plate (hot rolling step). (II) A step of annealing a hot-rolled plate to a hot-rolled plate as needed (hot-rolled plate annealing step). (III) A step of pickling and cold-rolling a hot-rolled plate after a hot-rolling step or a hot-rolled plate annealing step to obtain a cold-rolled plate (cold rolling step). (IV) Process of performing finish annealing on a cold rolled plate (finish annealing process) (V) A process of applying skin pass rolling to a cold rolled plate after a finish annealing process (skin pass process). [0052] (Hot rolling process) In the hot rolling process, the slab is heated and hot rolled to make a hot rolled plate. As described above, the C content of the non-oriented electrical steel sheet in the state of the split type stator needs to be 0.0015% or less. However, when the C content is reduced from the molten steel stage, the Goss orientation does not become dominant after strain relief annealing. When the strain-removing annealing is performed, the Goss-oriented crystal grains are preferentially grown. However, if the C content is reduced from the molten steel stage, the number of Goss-oriented grains that are the core of the growth is reduced, and the strain-removing annealing is performed. Later, the GOSS direction does not become dominant. Similarly, when decarburization annealing is performed before finish annealing to reduce the C content, the GOSS orientation does not become dominant after strain relief annealing. Therefore, the C content at the steelmaking stage is 0.0025 to 0.0100% (the C content of the slab is 0.0025 to 0.0100%). Since the content of the elements other than C does not change in the middle of the process, a slab having the same composition as that of the target non-oriented electrical steel sheet may be used. The hot rolling conditions are not particularly limited. The conditions may be determined according to the required thickness and characteristics. [0053] (Hot rolled plate annealing process) The hot-rolled plate obtained by hot rolling may be annealed by hot-rolled plate if necessary. By performing hot-rolled sheet annealing, deterioration of surface quality due to rigging can be avoided, and the Goss orientation becomes more dominant after strain removal annealing, which is preferable. [0054] (Cold rolling process) In the cold rolling process, the hot rolled plate after the hot rolling process or the hot rolling plate annealing process is pickled and cold rolled to obtain a cold rolled plate. The conditions for cold rolling are not limited, but it is preferable that the temperature of the steel sheet is 150 ° C. or higher before or during cold rolling because cracking of the steel sheet can be prevented and the Goss orientation becomes dominant during strain removal annealing. [0055] (Finishing annealing process) In the method for manufacturing grain-oriented electrical steel sheets according to this embodiment, decarburization is performed in the finish annealing step. Specifically, decarburization is performed by setting the annealing atmosphere in the finishing annealing step to a temperature range in which the annealing temperature is 650 ° C. or higher and satisfying the following equation (ii). By this finish annealing step, it is possible to avoid the formation of carbides that hinder the growth of the Goss orientation during strain relief annealing. In addition, an internal oxide layer is formed. 0.05

orientation of the stator piece was measured by X-ray diffraction with the extending direction of the teeth as a reference for the crystal axis in the case of the split type stator. [0073] The magnetic characteristics are the magnetic flux density when the non-oriented electrical steel sheet from which the stator piece is punched is excited at 5000 A / m in the rolling direction of a 55 mm square single plate test piece that is annealed so as to have the same conditions as the stator piece. It was evaluated by the ratio of B50 to the saturation magnetic flux density Bs (B50 / Bs) and the iron loss W 10/400 when excited at 1.0 T400 Hz. If B50 / Bs is 0.85 or more and iron loss W 10/400 is 12 W / kg or less, it is judged that the magnetic characteristics are excellent. In addition, for the measurement of Young's modulus, one steel plate was taken from the above stator piece so that the Young's modulus in the circumferential direction of the yoke could be measured, and the length was 50 mm. The scope of the claims [Claim 1] The chemical composition is mass%, C: 0.0015% or less, Si: 2.5-4.0%, Contains, The average crystal grain size is 10-40 μm, There is an internal oxide layer with a thickness of 0.5 to 3.0 μm in the plate thickness direction from the surface. Non-oriented electrical steel sheet. [Claim 2] The chemical composition is by mass% C: 0.0015% or less, Si: 2.5-4.0%, Mn: 0.05-2.0%, Sol. Al: 0.0005 to 1.50%, P: 0.080% or less, S: 0.0030% or less, Ti: 0.0030% or less, Ni: 0 to 0.10%, Cu: 0 to 0.10%, Cr: 0 to 0.10%, Sn: 0 to 0.20%, Ca: 0 to 0.0050%, Mg: 0 to 0.0050%, REM: 0 to 0.0050%, Remaining: Fe and impurities, The non-oriented electrical steel sheet according to claim 1. [Claim 3] EL / E c, which is the ratio of Young's modulus EL in the rolling direction to Young's modulus E c in the direction perpendicular to the rolling direction, is 0.90 or more. The non-oriented electrical steel sheet according to claim 1 or 2. [Claim 4] The tensile strength is (230 + 100 × ([Si] +0.5 × [sol.Al])) MPa or more, and the elongation is less than 20%. The non-oriented electrical steel sheet according to any one of claims 1 to 3. Here, [Si] is the Si content in mass% in the non-oriented electrical steel sheet, [sol. Al] is sol. Al content. [Claim 5] It is a split type stator for rotary electric machines that is divided into multiple stator pieces in the circumferential direction. With a cylindrical yoke that extends in the axial direction, Equipped with multiple teeth extending radially from the inner peripheral surface of the yoke, The stator piece is made by laminating a plurality of non-oriented electrical steel sheets. When the extending direction of the teeth is used as the reference for the crystal axis, The X-ray random intensity ratio of the {110} <001> orientation of the stator piece is 5 or more. The average crystal grain size of the non-oriented electrical steel sheet is 100 to 200 μm. The chemical composition of the non-oriented electrical steel sheet is mass%. C: 0.0015% or less, and Si: contains 2.5 to 4.0%, Split type stator. [Claim 6] The value of B50 / Bs in the direction in which the teeth of the stator piece is extended is 0.85 or more. The Young's modulus E (GPa) in the circumferential direction of the yoke satisfies the following equation (i). The split type stator according to claim 5. E ≧ 205-3.3 × [Si] +10 ・ ・ ・ (i) However, [Si] in the above formula represents the Si content in the non-oriented electrical steel sheet in mass%. [Claim 7] The chemical composition of the non-oriented electrical steel sheet is by mass%. C: 0.0015% or less, Si: 2.5-4.0%, Mn: 0.05-2.0%, Sol. Al: 0.0005 to 1.50%, P: 0.080% or less, S: 0.0030% or less, Ti: 0.0030% or less, Ni: 0 to 0.10%, Cu: 0 to 0.10%, Cr: 0 to 0.10%, Sn: 0 to 0.20%, Ca: 0 to 0.0050%, Mg: 0 to 0.0050%, REM: 0 to 0.0050%, Remaining: Fe and impurities, The split stator according to claim 5 or 6. [Claim 8] The split stator according to any one of claims 5 to 7 and the split stator. The rotor placed on the inner peripheral side of the split type stator and A case is provided in which the stator pieces are brought into close contact with the plurality of stator pieces from the outer periphery of the yoke and the stator pieces are fixed. Rotating electric machine.