The present invention is non-oriented electrical steel sheet, a method of manufacturing a manufacturing method and motor core of a non-oriented electrical steel sheet.
BACKGROUND
[0002]
　In recent years, attention has been focused on global environmental problems, a need for a commitment to energy conservation is becoming increasingly more, is among them high efficiency of electrical equipment, there has been a strong demand in recent years. Therefore, even in the non-oriented electrical steel sheet is widely used as a core material such as a motor or transformer, demand for improvement in the magnetic properties are further strengthened. In particular, electric vehicles and motors for hybrid vehicles efficiency of the motor progresses, and, in the motor compressor, the tendency is remarkable.
[0003]
　Motor core of motors as described above is composed of a stator is a stator, a rotor and a rotor. When manufacturing such a motor core is a non-oriented electrical steel sheet after laminating punched into the shape of the motor core, core annealing (stress relief annealing) is performed. The core annealing is generally and are performed in an atmosphere containing nitrogen, the non-oriented electrical steel sheet during the core annealing ends up nitriding, there is a problem that the iron loss deteriorates.
[0004]
　Conventionally been various proposals for the purpose of suppressing the deterioration of the iron loss (Patent Documents 1-3). However, in the prior art, it is difficult to sufficiently suppress the deterioration of the iron loss due to nitriding of a non-oriented electrical steel sheet.
CITATION
Patent Document
[0005]
Patent Document 1: JP-A-10-183310 Patent Publication
Patent Document 2: JP 2003-293101 Patent Publication
Patent Document 3: JP 2014-196559 JP
Summary of the Invention
Problems that the Invention is to Solve
[0006]
　The present invention is non-oriented electrical steel sheet and a manufacturing method thereof deterioration of iron loss caused by nitriding of a non-oriented electrical steel sheet is sufficiently suppressed at the time of stress relief annealing, with non-oriented electrical steel sheet of a low iron loss and to provide a method of manufacturing a motor core.
Means for Solving the Problems
[0007]
　The present inventors have conducted extensive studies to solve the above problems. As a result, deterioration of the iron loss due to nitriding of the steel sheet, the N incorporated into the steel sheet by nitriding, ternary precipitates (Si, Mn) N by coupling with Mn in the steel occurs, the precipitation things revealed that caused by inhibiting domain wall motion. At the time of stress relief annealing, if there is Mn binding with N, found that it (Si, Mn) N deposition is suppressed, suppressing the deterioration of the iron loss.
[0008]
　The present inventors have found that further intensive studies based on these findings, and conceived to aspects of the invention described below.
[0009]
　(1)
　in
　mass%,
　C:
　0.0010% ~ 0.0050%, Si: 2.5% ~ 4.0%, Al:
　0.0001% ~ 2.0%, Mn: 0.1% ~
　% 3.0,
　P:
　0.005% ~ 0.15%, S: 0.0001% ~ 0.0030%, Ti:
　0.0005% ~ 0.0030%, N: 0.0010% ~ 0.
　% 0030,
　Sn:
　0.00% ~ 0.2%, Sb: 0.00% ~ 0.2%,
　Ni: 0.00% ~ 0.2%, Cu: 0.00% ~ 0.2% ,
　Cr:
　0.00% ~
　0.2%, Ca: 0.0000% ~ 0.0025%, REM: 0.0000% ~ 0.0050%, and
　balance: Fe and impurities,
　in represented by the chemical composition has,
　from the surface of the base steel, the average value of the Mn concentration in the range up to depth 2μm from the surface of the ground iron [Mn 2 ], the surface of the ground iron The Mn concentration depth at the position of 10μm from the [Mn 10When a], the base steel is non-oriented electrical steel sheet characterized by satisfying Equation 1 below.
　≦ 0.1 [Mn 2 ] / [Mn 10 ] ≦ 0.9 (Equation 1)
[0010]
　(2)
　the non-oriented electrical steel
　sheet, Sn: 0.01% ~ 0.2%, and
　Sb: 0.01% ~ 0.2%
　characterized in that it comprises one or more selected from the group consisting of non-oriented electrical steel sheet according to (1) and.
[0011]
　(3)
　the non-oriented electrical steel
　sheet, Ni:
　0.01% ~ 0.2%, Cu: 0.01% ~ 0.2%, and
　Cr: 0.01% ~ 0.2%
　group consisting non-oriented electrical steel sheet according to, characterized in that it comprises one or more selected from (1) or (2).
[0012]
　(4)
　the non-oriented electrical steel
　sheet, Ca: 0.0005% ~ 0.0025%, and
　REM: 0.0005% ~ 0.0050%
　characterized in that it comprises one or more selected from the group consisting of non-oriented electrical steel sheet according to any one of to (1) to (3).
[0013]
　(5)
　provided with a surface insulating film of the ground iron
　adhering amount of the insulating coating, 400 mg / m 2 or more 1200 mg / m 2 or less,
　divalent Fe content in the insulation coating and trivalent Fe content, 10 mg / m in total 2 or 250 mg / m 2 non-oriented electrical steel sheet according to any one of, wherein (1) to (4) is not more than.
[0014]
　(6)
　a step of obtaining a hot rolled steel sheet by performing hot rolling of the steel ingot,
　and performing hot-rolled sheet annealing of the hot-rolled steel sheet,
　after the hot rolled sheet annealing, and performing pickling,
　the after pickling, obtaining a cold-rolled steel sheet by performing cold rolling,
　it said the step of performing finish annealing of the cold-rolled steel sheet,
has,
　the hot rolled sheet annealing is, 60 ° C. dew point -40 ℃ or higher follows and, an annealing temperature of 900 ° C. or higher 1100 ° C. or less, the soaking time of 300 seconds or less than 1 second, carried out leaving the scale generated in said hot rolling,
　the pickling, the steel matrix from the surface, the average value of the Mn concentration in the range of depth from the surface of the ground iron to 5 [mu] m [Mn 5 ], the Mn concentration in the depth 10μm position from the surface of the ground iron [Mn 10 ] and when the ground iron after the pickling is performed so as to satisfy the equation 2 below,
　the finish annealing It is the annealing temperature is less than 900 ° C.,
　the steel ingot is a
　mass%,
　C: 0.0010% ~ 0.0050%,
　Si: 2.5% ~ 4.0%, Al: 0.0001% ~
　% 2.0,
　Mn: 0.1% ~ 3.0%, P: 0.005% ~ 0.15%,

　S:
　0.0001% ~ 0.0030%, Ti: 0.0005% ~ 0.0030%,
　N: 0.0010% ~ 0.0030%, Sn: 0.00% ~
　0.2%, Sb:
　%
　~ 0.2 0.00%, Ni: 0.00% ~
　0.2%, Cu: 0.00% ~ 0.2%, Cr: 0.00% ~
　0.2%, Ca: 0.
　% ~ 0.0025 0000%, REM: 0.0000% ~ 0.0050%, and
　balance: Fe and impurities,
　the manufacturing method of the non-oriented electrical steel sheet characterized by having in a chemical composition represented.
　≦ 0.1 [Mn 5 ] / [Mn 10 ] ≦ 0.9 (Equation 2)
[0015]
　(7)
　after said final annealing method for producing a non-oriented electrical steel sheet according to (6), further comprising a step of forming an insulating film on the surface of the ground iron.
[0016]
　(8)
　The steel
　mass, Sn: 0.01% ~ 0.2%, and
　Sb: 0.01% ~ 0.2%
　, characterized in that it comprises one or more selected from the group consisting of ( method for producing a non-oriented electrical steel sheet according to 6) or (7).
[0017]
　(9)
　the steel
　mass, Ni:
　0.01% ~ 0.2%, Cu: 0.01% ~ 0.2%, and
　Cr: 0.01% ~ 0.2%
　is selected from the group consisting of method for producing a non-oriented electrical steel sheet according to any one of, wherein (6) to (8) that comprises one or more was.
[0018]
　(10)
　The steel
　mass, Ca: 0.0005% ~ 0.0025%, and
　REM: 0.0005% ~ 0.0050%
　, characterized in that it comprises one or more selected from the group consisting of ( method for producing a non-oriented electrical steel sheet according to any one of 6) to (9).
[0019]
　(11)
　a step of punching the non-oriented electrical steel sheet core shape,
　a step of laminating the non-oriented electrical steel sheets punched,
　and performing stress relief annealing of the non-oriented electrical steel sheet described above laminated,
it has a ,
　in the stress relief annealing, the proportion of nitrogen in the annealing atmosphere was 70% by volume or more, the stress relief annealing temperature of 750 ° C. or higher 900 ° C. or less,
　the non-oriented electrical steel sheet containing, by mass%,
　C: 0.
　%
　~ 0.0050 0010%, Si: 2.5% ~ 4.0%,
　Al: 0.0001% ~ 2.0%, Mn:
　0.1% ~ 3.0%, P: 0.005%
　0.15%

　0.0001%~, ~ 0.0030%, Ti: 0.0005% ~ 0.0030%, N:
　0.0010% ~ 0.0030%, Sn: 0.00% ~ 0
　% .2,
　Sb: 0.00% ~ 0.2%, Ni: 0.00% ~
　0.2%, Cu:
　% ~
　0.2 .00%,
　REM: 0.0000% ~ 0.0050%, and
　balance: Fe and impurities,
　have in a chemical composition represented,
　in the range from the surface of the base steel, up to 2μm depth from the surface of the ground iron the average value of the Mn concentration [Mn 2 ], depth from the surface of the ground iron the Mn concentration at the position of 10 [mu] m [Mn 10 manufacture of motor cores and satisfies the equation 1 below when the ' Method.
　≦ 0.1 [Mn 2 ] / [Mn 10 ] ≦ 0.9 (Equation 1)
[0020]
　(12)
　motor core manufacturing method according to, characterized in that it comprises a surface insulating film of the ground iron (11).
[0021]
　(13)
　The non-oriented electrical steel
　sheet, Sn: 0.01% ~ 0.2%, and
　Sb: 0.01% ~ 0.2%
　characterized in that it comprises one or more selected from the group consisting of motor core manufacturing method according to (11) or (12) and.
[0022]
　(14)
　The non-oriented electrical steel
　sheet, Ni:
　0.01% ~ 0.2%, Cu: 0.01% ~ 0.2%, and
　Cr: 0.01% ~ 0.2%
　group consisting any motor core manufacturing method according to one of which comprises one or more selected (11) to (13) from.
[0023]
　(15)
　The non-oriented electrical steel
　sheet, Ca: 0.0005% ~ 0.0025%, and
　REM: 0.0005% ~ 0.0050%
　characterized in that it comprises one or more selected from the group consisting of to (11) or motor core manufacturing method according to any one of (14).
The invention's effect
[0024]
　According to the present invention, since the Mn concentration in the interior of the base steel is appropriate, the deterioration of the iron loss due to nitriding of the non-oriented electrical steel sheet during stress relief annealing can be sufficiently suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025]
[1] Figure 1 is a sectional view showing a non-oriented electrical steel sheet according to the embodiment of the present invention.
FIG. 2 is a schematic diagram showing the vicinity of the surface of the base steel in the non-oriented electrical steel sheet according to the embodiment of the present invention.
FIG. 3 is a schematic diagram showing the distribution of Mn concentration in the base steel.
[4] FIG 4 is a flowchart showing an example of a method for producing a non-oriented electrical steel sheet according to the embodiment of the present invention.
FIG. 5 is a schematic view for explaining a method of manufacturing the non-oriented electrical steel sheet according to the embodiment of the present invention.
[6] FIG 6 is a flowchart showing an example of a motor core manufacturing method according to an embodiment of the present invention.
DESCRIPTION OF THE INVENTION
[0026]
　First described the chemical composition of the steel ingot used for non-oriented electrical steel sheet and a manufacturing according to an embodiment of the present invention. Although details will be described later, the non-oriented electrical steel sheet according to the embodiment of the present invention, hot rolling of the steel ingot, hot-rolled sheet annealing, pickling, is produced through cold rolling, and finish annealing and the like. Therefore, the chemical composition of the non-oriented electrical steel sheet and the steel ingot is not only characteristic of the non-oriented electrical steel sheet, is taken into consideration these processes. In the following description, "%" is a unit of content of each element contained in the non-oriented electrical steel sheet, in particular means "% by mass" unless otherwise specified. Non-oriented electrical steel sheet according to the present embodiment, C: 0.0010% ~ 0.0050%, Si: 2.5% ~ 4.0%, Al: 0.0001% ~ 2.0%, Mn: 0.1% ~ 3.0%, P: 0.005% ~ 0.15%, S: 0.0001% ~ 0.0030%, Ti: 0.0005% ~ 0.0030%, N: 0. 0010% ~ 0.0030%, Sn: 0.00% ~ 0.2%, Sb: 0.00% ~ 0.2%, Ni: 0.00% ~ 0.2%, Cu: 0.00% ~ 0.2%, Cr: 0.00% ~ 0.2%, Ca: 0.0000% ~ 0.0025%, REM: 0.0000% ~ 0.0050%, and balance: tables of Fe and impurities It has a chemical composition that is. As the impurity, those included in raw materials such as ores and scrap, intended to be included in the manufacturing process, is exemplified.
[0027]
　(C: 0.0010 Pasento ～ 0.0050 Pasento)
　C causes deterioration of iron loss. The C content is 0.0050% greater, core loss is degraded in steel, it is impossible to obtain good magnetic properties. Therefore, C content is 0.0050% or less, preferably a 0.0040%, more preferably 0.0030% or less. On the other hand, C content is less than 0.0010%, the magnetic flux density decreases in the steel plate, it is impossible to obtain good magnetic properties. Therefore, C content is 0.0010% or more, preferably 0.0015% or more.
[0028]
　(Si: 2.5% ~
　4.0%) Si is to increase the electrical resistance of the steel to reduce the eddy current loss, thereby improving the high-frequency iron loss. Further, Si improves the strength of the steel sheet by solid solution strengthening. The Si content is less than 2.5%, the effect can not be sufficiently obtained by this action. Therefore, Si content is set to 2.5% or more, preferably 2.7% or more, more preferably 3.0% or more. On the other hand, Si content is 4.0 percent, the workability is remarkably deteriorated, it is difficult to carry out cold rolling. Therefore, Si content is not more than 4.0%, preferably not more than 3.7%, more preferably at most 3.5%.
[0029]
(Al: 0.0001% ~
　2.0%) Al is to reduce the eddy current loss by increasing electrical resistance of the steel sheet, thereby improving the high-frequency iron loss. On the other hand, Al has a processability in the manufacturing process of the steel sheet, to reduce the magnetic flux density of the product, in this aspect, Al is preferably contained less. The Al content is less than 0.0001%, the load in the steel is high, the cost is increased. Therefore, Al content is set to 0.0001% or more, preferably 0.0010% or more, more preferably 0.0100% or more. On the other hand, Al content is 2.0%, the magnetic flux density is significantly reduced in the steel plate, or it is difficult to carry out cold rolling by embrittlement. Therefore, Al content is set to 2.0% or less, preferably 1.0% or less, more preferably 0.7% or less.
[0030]
(Mn: 0.1% ~
　3.0%) Mn is to increase the electrical resistance of the steel to reduce the eddy current loss, thereby improving the high-frequency iron loss. The Mn content is less than 0.1%, the effect can not be sufficiently obtained by this action. Therefore, Mn content is 0.1% or more, preferably 0.3% or more, more preferably 0.5% or more. On the other hand, Mn content is 3.0 percent, decrease in magnetic flux density becomes remarkable. Therefore, Mn content is not more than 3.0%, preferably 2.0% or less, more preferably 1.3% or less.
[0031]
(P: 0.005% ~ 0.15%)
　P is a solid solution strengthening ability is large, to increase the advantageous {100} texture to improve the magnetic properties, to achieve both high strength and high magnetic flux density . Furthermore, the increase in {100} texture, to contribute to reducing the anisotropy of mechanical properties in the plate surface of the non-oriented electrical steel sheet, P is, in the non-oriented electrical steel sheet during punching improve the dimensional accuracy. The P content is less than 0.005%, the effect can not be sufficiently obtained by this action. Accordingly, P content is 0.005% or more, preferably 0.01% or more, more preferably 0.04% or more. On the other hand, P content is 0.15 percent, the ductility of the non-oriented electrical steel sheet is remarkably lowered. Accordingly, P content is not more than 0.15%, preferably not more than 0.10%, more preferably at most 0.08%.
[0032]
(S: 0.0001% ~ 0.0030%)
　S increases iron loss by forming fine precipitates of MnS, deteriorating the magnetic properties of non-oriented electrical steel sheet. Thus, S content is set to 0.0030% or less, preferably a 0.0020%, more preferably 0.0010% or less. On the other hand, the S content is less than 0.0001%, the cost is increased. Thus, S content is 0.0001% or more, preferably 0.0003% or more. An increase in the N concentration from the viewpoint of suppressing by nitriding, S content is more preferably 0.0005% or more.
[0033]
(N: 0.0010% ~ 0.0030%)
　N increases iron loss causing magnetic aging, degrading the magnetic properties of non-oriented electrical steel sheet. Therefore, N content is set to 0.0030% or less, preferably a 0.0025% or less, more preferably 0.0020%. On the other hand, N content is less than 0.0010%, the cost is increased. Therefore, N content is 0.0010% or more, preferably 0.0015% or more.
[0034]
(Ti: 0.0005% ~
　0.0030%) Ti is, C, N, combines with Mn or the like to form inclusions, deteriorates the magnetic properties by inhibiting grain growth during strain relief annealing . Therefore, Ti content is set to 0.0030% or less, preferably 0.0015% or less, more preferably 0.0010% or less. On the other hand, Ti content is 0.0005%, the cost increases. Therefore, Ti content is set to 0.0005% or more, preferably 0.0006% or more.
[0035]
　(Sn: 0.00% ~ 0.2% and Sb: 1 or more selected from the group consisting of% ~ 0.2
　0.00%) Sn and Sb, oxidation during segregation annealing on the surface of the steel sheet by suppressing, to ensure low core loss. Therefore, Sn or Sb may be contained. In one or more content is less than 0.01% each selected from the group consisting of Sn and Sb, there is the effect due to this effect can not be obtained sufficiently. Thus, one or more content selected from the group consisting of Sn and Sb, respectively preferably 0.01% or more, more preferably 0.03% or more. Meanwhile, one or more content selected from the group consisting of n and Sb is at 0.2 percent, respectively, cold rolling becomes difficult ductility of the steel matrix is reduced. Thus, one or more content selected from the group consisting of Sn and Sb, respectively 0.2% or less, preferably 0.1% or less.
[0036]
　(Ni: 0.00% ~ 0.2% , Cu: 0.00% ~ 0.2% and Cr: 1 or more selected from the group consisting of% ~ 0.2
　0.00%) Ni, Cu and Cr, and reducing the core loss by increasing specific resistance. Accordingly, Ni, Cu, or Cr may be contained. Ni, the one or more content is less than 0.01% each selected from the group consisting of Cu and Cr, there is the effect due to this effect can not be obtained sufficiently. Accordingly, Ni, 1 or more content selected from the group consisting of Cu and Cr, respectively preferably 0.01% or more, more preferably 0.03% or more. On the other hand, Ni, 1 or more content selected from the group consisting of Cu and Cr in 0.2 percent respectively, the magnetic flux density is degraded. Accordingly, Ni, 1 or more content selected from the group consisting of Cu and Cr, respectively 0.2% or less, preferably 0.1% or less.
[0037]
　(Ca: 0.0000% ~ 0.0025% and REM: 0.0000% ~ 0.0050 1 or more selected from the group consisting
　of%) Ca and REM (Rare Earth Metal: rare earth element) is final annealing to promote the growth of crystal grains at the time. Therefore, Ca or REM may be contained. In one or more content is less than 0.0005%, respectively selected from the group consisting of Ca and REM, there is the effect due to this effect can not be obtained sufficiently. Thus, one or more content selected from the group consisting of Ca and REM are each preferably set to 0.0005% or more, more preferably 0.0010% or more. On the other hand, the Ca content 0.0025%, the above effect is saturated and the cost increases. Therefore, Ca content is 0.0025% or less. The REM content is 0.0050% greater than the effect is saturated and the cost increases. Therefore, REM content is 0.0050% or less, preferably 0.0030% or less.
[0038]
　(Other)
　Furthermore, non-oriented electrical steel sheet according to the present embodiment, Pb, Bi, V, As, may contain 0.0001% to 0.0050%, respectively, etc. B.
[0039]
　In the case where afterwards measure the chemical composition of the steel ingot used for non-oriented electrical steel sheet and its production according to the present embodiment, it is possible to use various known measurement methods. For example, it may be appropriately used ICP-MS (inductively coupled plasma mass spectrometry) method, or the like.
[0040]
　Next, the non-oriented electrical steel sheet according to the embodiment of the present invention will be described with reference to FIG. Figure 1 is a sectional view showing a non-oriented electrical steel sheet according to the embodiment of the present invention. Non-oriented electrical steel sheet 10 according to this embodiment includes a back iron 11 having the predetermined chemical composition. The thickness t is 0.35mm greater than the base steel 11, it may not be able to reduce the high-frequency iron loss. Therefore, the thickness t of the base steel 11 is preferably set to 0.35mm or less, more preferably at most 0.31 mm. If it is less than the thickness t of the base iron 11 0.10 mm, there is a possibility that the sheet passage of annealing line for sheet thickness is thin becomes difficult. Therefore, the thickness t of the base steel 11 is preferably not less than 0.10 mm, more preferably at least 0.19 mm.
[0041]
　On the surface of the base steel 11, it may be provided with an insulating coating 13. Non-oriented electrical steel sheet 10, for use by stacking After punching a core blank, by providing the insulating film 13 on the surface of the base steel 11, it is possible to reduce the eddy current between the steel sheet, as a core it is possible to reduce the eddy current loss.
[0042]
　Insulating coating 13, as long as it is used as an insulating film of non-oriented electrical steel sheet, is not particularly limited, it is possible to use a known insulating film. As such an insulating film, for example, an inorganic material as a main component, and a further composite insulating coating containing an organic material. The composite insulating coating, for example, chromic acid metal salts, phosphoric acid metal salts, or colloidal silica, Zr compound, as a main component at least one of inorganic Ti compound or the like, particles of fine organic resin is dispersed and it has an insulating coating. In particular, in recent years there is an increasing demand, from the viewpoint of reducing the environmental impact during manufacturing, coupling agent of the phosphoric acid metal salt and Zr, or Ti, or, using these carbonates or ammonium salts as starting materials insulation film is used.
[0043]
　Adhesion amount of the insulating coating 13 is not particularly limited, for example, preferably per side 400 mg / m 2 or more 1200 mg / m 2 or less. Insulating coating 13 of such adhesion amount that provided on the surface of the base steel 11, it is possible to maintain excellent uniformity. Adhesion amount of the insulating coating 13 per one side 400 mg / m 2 by weight, it is difficult to retain good uniformity. Accordingly, the adhesion amount of the insulating coating 13, preferably per side 400 mg / m 2 and more, and more preferably per side 800 mg / m 2 and more. On the other hand, 1200 mg / m per amount adhering one surface of the insulating coating 13 2 In greater, it takes longer than baking time of usual insulating film, the cost becomes high. Accordingly, the adhesion amount of the insulating coating 13, preferably per side 1200 mg / m 2 and less, more preferably 1000 mg / m per surface 2 or less. Note that the method of deposition of the insulating film 13, when ex-post measurements, it is possible to use various known measuring methods, for example, measuring the mass difference before and after immersion in sodium hydroxide solution, the calibration curve method X-ray fluorescence method and the like may be appropriately utilized using.
[0044]
　Fe content of divalent Fe content and trivalent in the insulating film 13, a metal Fe terms, preferably 10 mg / m 2 or more 250 mg / m 2 or less. Divalent Fe content and Fe content of divalent 3 10 mg / m 2 is less than in the stress relief annealing to be performed when producing a motor core, sufficient permeation of oxygen or the like which inevitably present in the atmosphere can not be suppressed, with it becomes difficult to improve the adhesion of the insulating coating 13, it is difficult to increase the annealing temperature in the stress relief annealing. Thus, divalent Fe content and trivalent Fe content is preferably 10 mg / m 2 and more, more preferably 50 mg / m 2 and more. On the other hand, divalent Fe content and trivalent Fe content 250 mg / m 2 in greater than it takes longer than usual insulating baking time of coating, the cost is high. Thus, divalent Fe content and trivalent Fe content is preferably 250 mg / m 2 and less, more preferably 200 mg / m 2Less. Factors that adhesion is improved in the steel matrix 11 and the insulating film 13, the presence of de-Mn layer is believed to be described later. Mn is, Al than or Si, easily oxidized in the vicinity of more surface of the oxygen-rich base steel 11, not easily oxidized inside the base iron 11. Thus, thickened external oxide film on the outermost surface layer is easily formed in the base steel 11. However, the presence of de-Mn layer, since the external oxide film is hardly formed an Mn concentrated layer increases the surface area of ​​processing solution with the base iron 11 of the insulating film 13 is reacted, divalent in the insulating film 13 Fe content and trivalent Fe content increases. By divalent Fe content in the insulation coating 13 and trivalent Fe content increases, before oxygen or the like which inevitably present in the atmosphere reaches the steel matrix 11, Fe ions and oxygen are bonded Therefore, it is possible to prevent the oxygen or the like is transmitted to the steel plate. Oxygen reaching the interface between the insulating film 13 and the base steel 11 is bonded to Si and Al in the steel to form an oxide film. By foreign matter such as the oxide film at the interface with the insulating coating 13 and the base iron 11, adhesion between the steel matrix 11 and the insulating film 13 is deteriorated. Therefore, adhesion between the steel matrix 11 and the insulating film 13 is considered to be improved by inhibition of permeation of oxygen or the like. Such a mechanism, the presence of de-Mn layer is considered to contribute to improvement of adhesion between the steel matrix 11 and the insulating film 13.
[0045]
　Next, a description will be given depth profile of Mn in the base steel in the non-oriented electrical steel sheet according to the embodiment of the present invention. As described above, the strain relief annealing are often performed in nitrogen as the non-oxidizing atmosphere. However, the progress of nitriding of the steel matrix in performing stress relief annealing, due to nitride (Si, Mn) by the precipitation of N, iron loss is deteriorated. In an inert atmosphere, using argon or helium instead of nitrogen, the nitride is suppressed, costly. Therefore, it is industrially crucial using nitrogen in performing stress relief annealing as a main atmosphere. Accordingly, the present inventors have obtained the finding that N is if there is no Mn of binding (Si, Mn) can suppress the precipitation of N, can suppress the deterioration of iron loss.
[0046]
　Increased N concentration by nitriding is limited to near the surface of the base steel. Therefore, if it is possible to reduce the Mn concentration near the surface of the base iron to N comes a solid solution, it is possible to suppress the precipitation of (Si, Mn) N. Further, in the top surface of the base steel, if it is possible to reduce the content of high N affinity Mn, N 2 also molecules to inhibit the reaction itself to blend into the base steel as to decompose N atoms It can become. Moreover, also by increasing solid solution S increases the solubility of MnS, it is possible to prevent entry of N into the steel. From these facts, the present inventors have found that to localized the distribution of Mn in the vicinity of the surface of the base steel, to suppress the deterioration of the iron loss at the time of stress relief annealing, found that good magnetic properties can be obtained It was.
[0047]
　Figure 2 is a schematic diagram showing the vicinity of the surface of the base steel in the non-oriented electrical steel sheet according to the embodiment of the present invention. In FIG. 2, for convenience, sets the x-axis positive direction in the direction toward the center in the thickness direction (depth direction) from the surface of the base steel 11 is described herein with reference to the coordinate axes.
[0048]
　Base steel 11 includes a base material 101, and a de-Mn layer 103. Preform 101, in the interior of the base steel 11, a portion which Mn is substantially uniformly distributed, Mn concentration in the mother material part 101 is substantially equal to the Mn content base iron 11 has It has become. De Mn layer 103 is a layer located on the surface side of the base steel 11, the Mn concentration of de Mn layer 103 has a relatively lower value than the Mn concentration of the base material portion 101.
[0049]
　Specifically, the origin of the surface of the base iron 11 of the x-axis (i.e., the position of x = 0 .mu.m) case of the, in the de-Mn layer 103, the relationship of Equation 1 below is satisfied. That is, from the surface of the base steel 11, [Mn average value of Mn concentration in the range of from 2μm depth from the surface of the base steel 11 2 Mn], in the depth 10μm position from the surface of the base iron 11 the concentration [Mn 10 when the, base steel 11 satisfy the equation 1 below. By relationship of Equation 1 below is satisfied, the non-oriented electrical steel sheet according to the present embodiment, by suppressing the deterioration of the iron loss at the time of stress relief annealing, it becomes possible to obtain excellent magnetic properties.
　≦ 0.1 [Mn 2 ] / [Mn 10 ] ≦ 0.9 (Equation 1)
[0050]
　Figure 3 is a schematic diagram showing the distribution of Mn concentration in the base steel. Than 3, there is no de-Mn layer in the base steel, when the distribution of Mn in the depth direction (x-direction) is uniform, Mn concentration, [Mn 10 if the value (in other words the, Further, even if the technology is applied to form an Al-concentrated layer as described in Patent Document 1, as indicated by a broken line in FIG. 3, Mn concentration near the surface of the base steel, the overall base steel It is considered to be higher than the value of the average Mn concentration. However, in the base steel in the non-oriented electrical steel sheet according to the present embodiment, the Mn concentration near the surface of the base steel is lower than the value of the average Mn concentration in the entire base steel.
[0051]
　That is, in the base steel in the non-oriented electrical steel sheet according to the present embodiment, by providing the de-Mn layer, as shown in FIG. 3, the depth 2 [mu] m from the surface of the base steel (x = 0μm) (x = 2μm the average value of the Mn concentration in the range up to the position of) ([Mn 2 ]) is, Mn concentration at a depth of 10 [mu] m (x = 10 [mu] m) ([Mn 10 is lower than]). Accordingly, as shown in the inequality of the most right side of the above equation 1, [Mn 2 ] / [Mn 10Concentration ratio represented by] is set to 0.9 or less, preferably 0.8 or less, more preferably 0.7 or less. This, Mn concentration in the de-Mn layer is meant that it is relatively lower than the average Mn concentration in the mother material part. In such de-Mn layer, because a small amount of Mn is excessively melted against S, S Those who are dispersed in solid solution than fixed as MnS is, entropy is large min stable . Therefore, when the solubility of MnS increases, considered dissolved S is increased. Therefore, by the solid solution S increases solubility of MnS is increased, an increase in the N concentration becomes possible to reduce the S content was difficult to achieve is a concern due to nitride, in particular grain growth after heat treatment improved Furthermore it is possible to suppress the deterioration of the iron loss in which it is. When segregation easily dissolved S to grain boundaries are present, because the N is blocked route to penetrate into the steel is considered to be difficult to nitride. Reducing the normal S content, dissolved S is reduced, N concentration is increased by nitriding. However, in the present embodiment, because even reduced S content S is present remains dissolved S without being fixed as MnS, it is possible to suppress the nitride. Further, by increasing solid solution S increases the solubility of MnS, it is possible to reduce the content of that previously required once was Sn and Sb in the reduction of S content, be the result produced at low cost it can. Further, by the solid solution S increases solubility of MnS is increased, it is possible to dissolved S is suppressed even permeation of oxygen as well as nitrogen, improves the adhesion between the insulating coating and the base steel after heat treatment can do.
[0052]
　On the other hand, Mn concentration in the de-Mn layer is too low, [Mn 2 ] / [Mn 10 when the concentration ratio represented by] is less than 0.1 has a low Mn content in the vicinity of the surface of the base iron it too, the high-frequency iron loss is deteriorated. Accordingly, as shown at the left side of the inequality in the formula 1, [Mn 2 ] / [Mn 10 Concentration ratio represented by] is set to 0.1 or more, preferably 0.2 or more, more preferably and 0.5 or more.
[0053]
　Mn concentration of the base steel along the depth direction from the surface of the base steel is a glow discharge optical emission spectrometer (Glow Discharge Spectroscopy: GDS) can be identified using. The measurement conditions GDS, in accordance with the analyzed material, DC mode, the high-frequency mode, in the present embodiment further has a pulse mode and the like are prepared, for analyzing a predominantly conductor base steel, what not much difference be measured in such a mode. Therefore, sputter mark becomes uniform, and to set the measurement time depth can analyze more than 10μm condition may be appropriately analyzed.
[0054]
　Non-oriented electrical steel sheet according to the present embodiment is provided with the configuration described above, it exhibits excellent magnetic properties. Various magnetic properties of the indicated non-oriented electrical steel sheet according to the present embodiment, Epstein method specified in JIS C2550, JIS C2556 veneer magnetic property measuring method specified in (Single Sheet Tester: SST) in accordance with such it is possible to measure.
[0055]
　Next, a method of manufacturing the non-oriented electrical steel sheet according to the embodiment of the present invention will be described with reference to FIGS. Figure 4 is a flow chart showing an example of a method for producing a non-oriented electrical steel sheet according to the embodiment of the present invention, FIG. 5, for explaining the method for producing a non-oriented electrical steel sheet according to the embodiment of the present invention it is a schematic diagram.
[0056]
　In the method of manufacturing the non-oriented electrical steel sheet according to the present embodiment, the hot rolling of the steel ingot having the above chemical composition, hot-rolled sheet annealing, pickling, cold rolling, finish annealing carried out. When forming an insulating film on the surface of the base steel, the formation of the insulating film after the final annealing is performed.
[0057]
　First, as shown in FIG. 4, heating the steel ingot (slab) having the above chemical composition to obtain a hot-rolled steel sheet subjected to hot rolling for heated steel ingot (S101). By performing such hot rolling, as shown in FIG. 5 (A), on the surface of the base steel 11, the scale S mainly containing Fe oxides are produced. In this hot rolling, Mn in the interior of the base steel 11 is considered to have substantially uniformly dispersed. The heating temperature of the steel ingot when subjected to hot rolling, is not particularly limited, for example, preferably set to 1050 ° C. or higher 1200 ° C. or less. For even thickness of hot-rolled steel sheet after hot rolling, is not particularly limited, in consideration of the final thickness of the base steel, e.g., is preferably about 1.5 mm ~ 3.0 mm.
[0058]
　As shown in FIG. 4, after the hot rolling, performing hot-rolled sheet annealing (S103). In the method of manufacturing the non-oriented electrical steel sheet according to the present embodiment, as shown in FIG. 5 (B), while depositing the scale S produced by hot rolling, performing hot-rolled sheet annealing. The atmosphere of the scale S and the hot-rolled plate during annealing which has been formed on the surface of the hot-rolled steel sheet, Mn contained in the base steel 11 is oxidized while diffusing the scale direction. As a result, the vicinity of the surface of the base steel 11, with Mn enriched layer 104 containing Mn oxide is formed, the number μm inner layer of the Mn-rich layer 104 (the base steel side), de-Mn layer 103 There is formed. The remainder of the base steel 11, as the base material portion 111 having a structure after hot rolled sheet annealing. Thus, in the manufacturing method of the non-oriented electrical steel sheet according to the present embodiment, since the Mn of Mn enriched layer 104 is formed under a more easily oxidized situation, suppliers of Mn to Mn enriched layer 104 Mn concentration of de Mn layer 103 is becomes even more lower than that of the conventional. Therefore, de-Mn layer is formed to have a concentration distribution of Mn as shown in FIG. On the other hand, after removing the scale S produced by hot rolling, even were hot-rolled sheet annealing under conditions as described below, since the Mn vicinity of the surface layer in the base steel 11 is not sufficiently oxidized, the it is impossible to form a de-Mn layer 103 as.
[0059]
　The dew point of less than -40 ℃ in the annealing atmosphere in the hot-rolled sheet annealing, since the oxygen source is only the scale of the surface layer, leaving Mn layer is not sufficiently formed. Thus, the dew point of the annealing atmosphere is set to -40 ℃ or higher, preferably between -20 ° C. or higher, more preferably -10 ° C. or higher. On the other hand, the dew point 60 ° C. than the annealing atmosphere, scale generated by Fe in the base steel is oxidized, the scale to be removed by pickling, the yield is deteriorated. Further, since the Fe in the base steel is oxidized, Mn concentrated layer and the de-Mn layer is lost. Thus, the dew point of the annealing atmosphere is less than 60 ℃, preferably a 50 ° C. or less, more preferably 40 ° C. or less.
[0060]
　Is lower than 900 ° C. the temperature of the hot-rolled sheet annealing, the crystal grains of the base steel is not sufficiently coarsened by annealing, no satisfactory magnetic characteristics. Therefore, the temperature of the hot-rolled sheet annealing and 900 ° C. or more, preferably 930 ° C. or higher, more preferably 950 ° C. or higher. On the other hand, when the temperature of the hot-rolled sheet annealing is 1100 ° C. greater than the base steel it will be broken in the cold rolling to be described later. Therefore, the temperature of the hot-rolled sheet annealing and 1100 ° C. or less, preferably a 1070 ° C. or less, more preferably 1050 ° C. or less.
[0061]
　The soaking time is less than 1 second, the crystal grains of the base steel is not sufficiently coarsened by annealing, no satisfactory magnetic characteristics. Accordingly, the soaking time was 1 second or longer, preferably 10 seconds or more, more preferably 30 seconds or more. On the other hand, the soaking time is 300 seconds, greater than the base steel will be broken in the cold rolling to be described later. Accordingly, the soaking time is not more than 300 seconds, preferably not more than 150 seconds, more preferably 90 seconds or less.
[0062]
　The cooling in the hot-rolled sheet annealing, the cooling rate in the temperature range up to 800 ° C. ~ 500 ° C., preferably for a 20 ° C. / sec ~ 100 ° C. / sec. With such a cooling rate, it is possible to obtain more excellent magnetic properties.
[0063]
　As shown in FIG. 4, after the hot-rolled sheet annealing, performing pickling (S105). In pickling, as shown in FIG. 5 (C), to remove the Mn-rich layer 104 is an internal oxide layer positioned on the outermost surface of the scale S and the base steel 11, de-Mn layer 103 is the outermost layer to control the pickling weight loss so. When performing the pickling, the steel sheet after pickling or during pickling, the Mn concentration in the depth direction was measured from time to time by GDS, eventually non-oriented electrical steel sheet obtained to satisfy equation 1 above , to control the pickling weight loss. Incidentally, pickling weight loss, for example, can be controlled by changing at least one of the temperature of the concentration, the pickling liquid accelerator used concentration of the acid used for pickling, the pickling. Specifically, pickling, the surface of the base steel, the depth from the surface of the base steel has a mean value of the Mn concentration in the range of from 5 [mu] m [Mn 5 ], 10 [mu] m depth from the surface of the base iron the Mn concentration at the position of [Mn 10 when the, By controlling the pickling weight loss so as to satisfy the equation 2 below, the non-oriented electrical steel sheet finally obtained and thus satisfy equation 1 above.
　≦ 0.1 [Mn 5 ] / [Mn 10 ] ≦ 0.9 (Equation 2)
[0064]
　As shown in FIG. 4, after pickling, performing cold rolling (S107). As shown in FIG. 5 (D), in the cold rolling, final thickness of the base iron 11 at a reduction rate such that less 0.35mm or 0.10 mm, the removal of the scale S and Mn enriched layer 104 pickling plate is rolled. By cold rolling preform 121 having a rolled structure is obtained.
[0065]
　As shown in FIG. 4, after cold rolling, performing finish annealing (step S109). As shown in FIG. 5 (E), in the method for manufacturing a non-oriented electrical steel sheet according to the present embodiment, de-Mn layer 103 is formed by performing a hot-rolled sheet annealing, the de-Mn layer 103 in the subsequent It is maintained. In the final annealing temperature is 900 ° C. or more, from the base material portion 121 Mn diffuses into the de-Mn layer 103, thereby de-Mn layer 103 is lost. Therefore, the final annealing temperature was lower than 900 ° C., preferably between 880 ° C. or less, more preferably 860 ° C. or less. By performing the final annealing such a final annealing temperature, which can give rise to suitably recrystallized in stress relief annealing is performed in the production of motor core, base metal with a fine recrystallized structure 101 It is obtained. On the other hand, in the final annealing temperature is lower than 750 ° C., too long annealing time, which may reduce productivity. Therefore, final annealing temperature is preferably set to 750 ° C. or higher, more preferably 775 ° C. or higher.
[0066]
　Annealing time may be appropriately set according to the final annealing temperature is, for example, can be 1 second to 150 seconds. Is less than the annealing time is 1 second, it is impossible to perform sufficient finish annealing, it may be difficult to cause an appropriately seed crystal base metal. Accordingly, the annealing time is preferably 1 second or more, more preferably 5 seconds or more. On the other hand, the annealing time is 150 seconds, more than too long annealing time, which may reduce productivity. Accordingly, the annealing time is preferably not more than 150 seconds, more preferably 100 seconds or less.
[0067]
　Heating rate in the temperature range of 950 ° C. or higher or less 700 ° C. preferably to 10 ℃ / s ~ 800 ℃ / s. It is less than the heating rate of 10 ° C. / s, in the non-oriented electrical steel sheet may not good magnetic characteristics. Therefore, the heating rate in the temperature range of 950 ° C. or less 700 ° C. or more, preferably a 10 ° C. / s or higher, more preferably 100 ° C. / s or higher. On the other hand, the heating rate is 800 ° C. / s greater, sometimes the effect of improving the magnetic properties is saturated. Therefore, the heating rate in the temperature range of 950 ° C. or higher or less 700 ° C. is preferably not more than 800 ° C. / s, more preferably from 400 ° C. / s or less.
[0068]
　Cooling rate in the temperature range of 900 ° C. or less 500 ° C. or higher, preferably 10 ℃ / s ~ 100 ℃ / s. The cooling rate is less than 10 ° C. / s, in the non-oriented electrical steel sheet may not good magnetic characteristics. Therefore, the cooling rate in the temperature range of 900 ° C. or less 500 ° C. or higher, preferably between 10 ° C. / s or higher, more preferably 20 ° C. / s or higher. On the other hand, the cooling rate is 100 ° C. / s greater, sometimes the effect of improving the magnetic properties is saturated. Therefore, the cooling rate in the temperature range of 00 ° C. below 500 ° C. or higher, preferably not more than 100 ° C. / s, more preferably less 70 ° C. / s.
[0069]
　In this way, it is possible to produce a non-oriented electrical steel sheet according to the embodiment of the present invention.
[0070]
　As shown in FIG. 5 (F), after the final annealing, if necessary, may also be formed of insulating coating 13 (S 111 in FIG. 4). The method of forming the insulating coating 13 is not limited in particular, by using a known insulating film treatment solution as described above may be carried out coating and drying of the treatment liquid by a known method. Note that the surface of the base steel which insulating film is formed, prior to applying the treatment solution, the state of de-Mn layer, to the extent that does not have a significant effect on the thickness and the like of the de-Mn layer, degreasing treatment with an alkali such as or, hydrochloric, sulfuric, pickling treatment by phosphoric acid and the like, may be subjected to any pretreatment. Moreover, the surface remains after annealing finish without performing these pre-treatment, may be formed of insulating coating.
[0071]
　Next, a method for manufacturing a motor core according to an embodiment of the present invention will be described with reference to FIG. 6, FIG. 6 is a flowchart showing an example of a motor core manufacturing method according to an embodiment of the present invention.
[0072]
　First, it punched non-oriented electrical steel sheet according to the present embodiment the core shape, by stacking the non-oriented electrical steel sheets punched out (S201), forming the shape of the desired motor core. For laminating non-oriented electrical steel sheets punched in the core shape, non-oriented electrical steel sheet for use in the manufacture of motor core, it is important that the surface of the base steel in which an insulating film is formed.
[0073]
　Thereafter, the non-oriented electromagnetic steel plates laminated on the core shape, performing stress relief annealing (core annealing) (S203).
[0074]
　The proportion of nitrogen is less than 70% by volume in the atmosphere of stress relief annealing, the cost of stress relief annealing is increased. Thus, the proportion of nitrogen in the atmosphere of stress relief annealing was set to 70% by volume or more, preferably 80 vol% or more, more preferably 90 vol% to 100 vol%, particularly preferably 97 vol% to 100 vol% to. Incidentally, the atmosphere gas other than nitrogen is not particularly limited, in general, can be used hydrogen, carbon dioxide, carbon monoxide, water vapor, a reducing mixed gas consisting of methane. To obtain these gases, a method of burning propane gas and natural gas, is generally employed.
[0075]
　The annealing temperature is lower than 750 ° C. of stress relief annealing, it can not be released sufficiently strain accumulated in the non-oriented electrical steel sheet. Therefore, the annealing temperature of stress relief annealing and 750 ° C. or higher, preferably 775 ° C. or higher. On the other hand, the annealing temperature is 900 ° C. greater than stress relief annealing, too grain growth of recrystallized structure proceeds, although the hysteresis loss is reduced, because the eddy current loss increases, resulting in an increase rather total core loss . Therefore, the annealing temperature of stress relief annealing, and 900 ° C. or less, preferably 850 ° C. or less.
[0076]
　Annealing time of stress relief annealing may be appropriately set depending on the annealing temperature, for example, it can be 10 minutes to 180 minutes. In less than 10 minutes annealing time, it may not be possible to release sufficiently distortion. Accordingly, the annealing time is preferably set to 10 minutes or more, more preferably 30 minutes or more. On the other hand, the annealing time of 180 minutes, more than too long annealing time, which may reduce productivity. Accordingly, the annealing time is preferably not more than 180 minutes, more preferably less 150 minutes.
[0077]
　Heating rate in the temperature range of 500 ° C. or higher 750 ° C. or less in the stress relief annealing is preferably a 50 ℃ / Hr ~ 300 ℃ / Hr. Is less than the heating rate of 50 ° C. / Hr, in motor core, may not good magnetic characteristics can not be obtained. Therefore, the heating rate in the temperature range of 500 ° C. or higher 750 ° C. or less, preferably a 50 ° C. / Hr or more, and more preferably 80 ° C. / Hr or more. On the other hand, the heating rate is 300 ° C. / Hr greater, sometimes the effect of improving such magnetic properties is saturated. Therefore, the heating rate at 500 ° C. or higher 750 ° C. or less of the temperature range is preferably not more than 300 ° C. / Hr, more preferably from 0.99 ° C. / Hr or less.
[0078]
　Cooling rate in the temperature range of 750 ° C. or less 500 ° C. or higher in the strain relief annealing is preferably a 50 ℃ / Hr ~ 500 ℃ / Hr. In cooling rate is less than 50 ° C. / Hr, in motor core, may not good magnetic characteristics can not be obtained. Therefore, the cooling rate in the temperature range of 750 ° C. or less 500 ° C. or more, preferably a 50 ° C. / Hr or more, and more preferably 80 ° C. / Hr or more. On the other hand, the cooling rate is 500 ° C. / Hr greater, becomes easily distorted due to thermal stress is introduced by uneven cooling occurs, sometimes the iron loss is deteriorated. Therefore, the cooling rate in the temperature range of 750 ° C. or less 500 ° C. or higher, preferably not more than 500 ° C. / Hr, more preferably from 200 ° C. / Hr or less.
[0079]
　In this way, it is possible to manufacture a motor core with non-oriented electrical steel sheet according to the embodiment of the present invention.
Example
[0080]
　Next, a description will be given of an embodiment of the present invention. Conditions in examples are an example of conditions adopted for confirming the workability and effects of the present invention, the present invention is not limited to this single example of conditions. The present invention does not depart from the gist of the present invention, as long as they achieve the object of the present invention, it is capable of adopting various conditions.　
[0081]
(Example 1)
　After heating the slab having the chemical composition shown in Table 1 to 1150 ° C., finish rolling temperature of 850 ° C., subjected to the hot rolling and the finish plate thickness 2.0 mm, wound at 650 ° C. to obtain a hot-rolled steel sheet Te. While depositing the scale formed on the surface of the steel sheet, subjected to dew point 10 ° C. and was 1000 ° C. × 50 seconds hot-rolled sheet annealing in a nitrogen atmosphere in the atmosphere, and pickling thereafter hydrochloric acid. When performing the pickling, acid concentration of the acid solution at the time of pickling, temperature, by changing the time, the [Mn 5 ] / [Mn 10 as the value of] These pickling plate performs cold rolling in which the sheet thickness and 0.25 mm, to obtain a cold-rolled steel sheet. Then, 20% hydrogen, 80% nitrogen, a mixed atmosphere of dew point was 0 ° C., subjected to annealing finishing under the conditions shown in Table 2 and Table 3, the insulating coating was applied to obtain a non-oriented electrical steel sheet. Incidentally, the cooling rate in the temperature range up to 800 ° C. ~ 500 ° C. at the time of hot-rolled sheet annealing and 40 ° C. / sec, the heating rate in the temperature range of 950 ° C. or higher or less 700 ° C. at the time of final annealing 100 ° C. / sec and then, the cooling rate in the temperature range of 900 ° C. or less 500 ° C. or higher during the final annealing was 30 ° C. / sec. For insulating coating, aluminum phosphate and particle size acrylic is 0.2 [mu] m - applying an insulating coating of a styrene copolymer resin emulsion to a predetermined coating weight in air, baked at 350 ° C. It was formed by. The analysis of the nitrogen concentration of the analysis and in the steel of the Mn concentration distribution by GDS, was performed after removing the insulation coating by hot alkaline. Table 1 Underline in to Table 3 indicates that the numerical value is outside the scope of the present invention.

WE claims

[Requested item 1]
　By
　mass%,
　C:
　0.0010% ~ 0.0050%, Si: 2.5% ~ 4.0%, Al:
　0.0001% ~ 2.0%, Mn: 0.1% ~ 3.0
　%,
　P:
　0.005% ~ 0.15%, S: 0.0001% ~
　0.0030%, Ti: 0.0005% ~ 0.0030%, N: 0.0010% ~ 0.0030%, 　sn:
　0.00% ~ 0.2%, Sb: 0.00% ~ 　0.2%, Ni: 0.00% ~ 0.2%, Cu: 0.00% ~ 　0.2%, Cr: 　% ~ 0.2 0.00%, 　Ca: 0.0000% ~ 0.0025%, REM: 0.0000% ~ 0.0050%, and 　balance: Fe and impurities, 　have in a chemical composition represented , 　from the surface of the base steel, the depth from the surface of the ground iron the average value of the Mn concentration in the range of from 2 [mu] m [Mn 2 ], from the surface of the ground iron Depth the Mn concentration at the position of 10 [mu] m [Mn 10 when the,

　0.1 ≦ [Mn 2 ] / [Mn 10 ] ≦ 0.9 (式1)
[Requested item 2]
　The non-oriented electrical steel
　sheet, Sn: 0.01% ~ 0.2%, and
　Sb: 0.01% ~ 0.2%
　claims, characterized in that it comprises one or more selected from the group consisting of non-oriented electrical steel sheet according to claim 1.
[Requested item 3]
　The non-oriented electrical steel
　sheet, Ni:
　0.01% ~ 0.2%, Cu: 0.01% ~ 0.2%, and
　Cr: 0.01% ~ 0.2%
　is selected from the group consisting of non-oriented electrical steel sheet according to claim 1 or 2, characterized in that it comprises at least one was.
[Requested item 4]
　The non-oriented electrical steel
　sheet, Ca: 0.0005% ~ 0.0025%, and
　REM: 0.0005% ~ 0.0050%
　claims, characterized in that it comprises one or more selected from the group consisting of non-oriented electrical steel sheet according to any one of claim 1 to 3.
[Requested item 5]
　Comprising an insulating film on the surface of the ground iron
　adhering amount of the insulating coating, 400 mg / m 2 or more 1200 mg / m 2 or less,
　Fe content of divalent Fe content and trivalent in the insulation coating , total 10 mg / m 2 or more 250 mg / m 2 non-oriented electrical steel sheet according to any one of claims 1 to 4, characterized in that at most.
[Requested item 6]
　Obtaining a hot-rolled steel sheet subjected to hot rolling of the steel ingot,
　and performing hot-rolled sheet annealing of the hot-rolled steel sheet,
　after the hot rolled sheet annealing, and performing pickling,
　the pickling after obtaining a cold-rolled steel sheet by performing cold rolling,
　and performing finish annealing of the cold-rolled steel sheet,
has,
　the hot rolled sheet annealing is the dew point and -40 ℃ above 60 ° C. or less, the annealing temperature of 900 ° C. or higher 1100 ° C. or less, the soaking time of 300 seconds or less than 1 second, carried out leaving the scale generated in said hot rolling,
　the pickling, the surface of the base steel, [Mn average value of Mn concentration depth from the surface of the ground iron in the range of up to 5 [mu] m 5 ], depth from the surface of the ground iron the Mn concentration at the position of 10 [mu] m [Mn 10 when a]
　and in the final annealing, Blunt temperature is less than 900 ° C.,
　the steel ingot is a
　mass%,
　C: 0.0010% ~ 0.0050%,
　Si: 2.5% ~ 4.0%, Al: 0.0001% ~ 2.
　Pasento 0,
　Mn: 0.1 Pasento ～ 3.0
　Pasento, P: 0.005 Pasento ～ 0.15 Pasento, S: 0.0001 Pasento ～ 0.0030 Pasento,
　Ti:

　0.0005% ~ 0.0030%, N: 0.0010% ~
　0.0030%, Sn: 0.00% ~ 0.2%, Sb: 0.00% ~
　0.2%, Ni:
　%
　~ 0.2 0.00%, Cu:
　0.00% ~ 0.2%, Cr: 0.00% ~ 0.2%, Ca: 0.0000% ~
　0.0025%, REM: 0. 0000% to 0.0050% and
　the balance: Fe and impurities,
　the manufacturing method of the non-oriented electrical steel sheet characterized by having in a chemical composition represented.
　≦ 0.1 [Mn 5 ] / [Mn 10 ] ≦ 0.9 (Equation 2)
[Requested item 7]
　After the finish annealing method for producing a non-oriented electrical steel sheet according to claim 6, characterized by further comprising a step of forming an insulating film on the surface of the ground iron.
[Requested item 8]
　The steel
　mass, Sn: 0.01% ~ 0.2%, and
　Sb: 0.01% ~ 0.2%
　claim, characterized in that it comprises one or more selected from the group consisting of 6 or method for producing a non-oriented electrical steel sheet according to 7.
[Requested item 9]
　The steel
　mass, Ni:
　0.01% ~ 0.2%, Cu: 0.01% ~ 0.2%, and
　Cr: 0.01% ~ 0.2%
　1 kind selected from the group consisting of method for producing a non-oriented electrical steel sheet according to any one of claims 6 to 8, characterized in that it comprises more.
[Requested item 10]
　The steel
　mass, Ca: 0.0005% ~ 0.0025%, and
　REM: 0.0005% ~ 0.0050%
　6 through claim, characterized in that it comprises one or more selected from the group consisting of method for producing a non-oriented electrical steel sheet according to any one of 9.
[Requested item 11]
　A step of punching the non-oriented electrical steel sheet core shape,
　and laminating a non-oriented electrical steel sheets punched out above,
　a step of performing stress relief annealing of the non-oriented electrical steel sheet described above laminated
have,
　the distortion in takes annealing, the proportion of nitrogen in the annealing atmosphere was 70% by volume or more, the stress relief annealing temperature of 750 ° C. or higher 900 ° C. or less,
　the non-oriented electrical steel sheet containing, by
　mass%, C: 0.0010% ~
　% 0.0050,
　Si: 2.5%
　~ 4.0%, Al: 0.0001% ~ 2.0%, Mn:
　0.1% ~ 3.0%, P: 0.005% ~ 0.
　% 15,
　S:
　0.0001% ~ 0.0030%, Ti: 0.0005% ~ 0.0030%, N:
　0.0010% ~ 0.0030%, Sn: 0.00% ~ 0.2% ,
　Sb:
　0.00% ~ 0.2%, Ni:
　0.00% ~ 0.2%, Cu: 0.00
　0.2%

　0.2%,~, Ca: 0.0000% ~ 0.0025%, REM: 0.0000% ~ 0.0050%, and
　Balance: Fe and impurities,
　have in chemical composition represented,
　from the surface of the base steel, the average value of the Mn concentration in the range up to depth 2μm from the surface of the ground iron [Mn 2 ], the ground depth from the surface of the iron the Mn concentration at the position of 10 [mu] m [Mn 10 motor core manufacturing method, characterized by satisfying the equation 1 below when the.
　≦ 0.1 [Mn 2 ] / [Mn 10 ] ≦ 0.9 (Equation 1)
[Requested item 12]
　Motor core manufacturing method according to claim 11, characterized in that it comprises a surface insulating film of the ground iron.
[Requested item 13]
　The non-oriented electrical steel
　sheet, Sn: 0.01% ~ 0.2%, and
　Sb: 0.01% ~ 0.2%
　claims, characterized in that it comprises one or more selected from the group consisting of motor core manufacturing method according to claim 11 or 12.
[Requested item 14]
　The non-oriented electrical steel
　sheet, Ni:
　0.01% ~ 0.2%, Cu: 0.01% ~ 0.2%, and
　Cr: 0.01% ~ 0.2%
　is selected from the group consisting of motor core manufacturing method according to any one of claims 11 to 13, characterized in that it comprises at least one was.
[Requested item 15]
　The non-oriented electrical steel
　sheet, Ca: 0.0005% ~ 0.0025%, and
　REM: 0.0005% ~ 0.0050%
　claims, characterized in that it comprises one or more selected from the group consisting of motor core manufacturing method according to any one of claim 11 to 14.