0001]The present disclosure relates to electrical steel sheets that are suitably used for applications such as magnetic cores of electric motors.
Background technology
[0002]Electrical steel sheets are used as iron core materials in rotating equipment such as motors and generators and stationary equipment such as small transformers, and play an important role in determining the energy efficiency of electrical equipment.
[0003]
　Typical characteristics of electrical steel sheets include iron loss and magnetic flux density. The lower the iron loss, the better, and the higher the magnetic flux density, the better. This is because when electricity is applied to the iron core to induce a magnetic field, the lower the iron loss, the less energy is lost due to heat. Further, the higher the magnetic flux density, the larger the magnetic field can be induced with the same energy.
[0004]
　Therefore, in order to save energy and meet the increasing demand for environmentally friendly products, non-oriented electrical steel sheets having low iron loss and high magnetic flux density and their manufacturing methods are required.
[0005]
　In such non-oriented electrical steel sheets, for example, when a blank for use as a stator core for a motor is cut out from the non-oriented electrical steel sheet and used, a space is formed in the central portion of the blank. If the portion cut out to form the space in the central portion is used as a blank for a rotor, that is, if a blank for a rotor and a blank for a stator core are produced from one non-oriented electrical steel sheet, the yield is increased. ,preferable.
[0006]
　For rotor applications that require strength to cope with high-speed rotation, for example, non-oriented electrical steel sheets having a finer crystal grain size or higher strength by leaving processing strains are required. On the other hand, the stator core does not need to have high strength, and is required to have excellent magnetic characteristics (high magnetic flux density and low iron loss) obtained by coarsening the crystal grain size and removing processing strain. Therefore, when a blank for a rotor and a blank for a stator core are manufactured from one non-oriented electrical steel sheet, the blank cut out for the stator is formed into a stator core and then processed into a high-strength non-oriented electrical steel sheet. It may be used by additional heat treatment in order to remove the strain due to the above and to coarsen the crystal grains and enhance the magnetic properties. This heat treatment is known as "strain removal annealing".
[0007]
　In strain relief annealing, the effect of releasing strain and coarsening the crystal grain size to improve iron loss is clear, but at the same time, a crystal orientation unfavorable for magnetic properties may develop and the magnetic flux density may decrease. Therefore, when particularly high magnetic characteristics are required, it is required to avoid a decrease in magnetic flux density due to strain relief annealing.
[0008]
　On the other hand, in Patent Document 1, X-rays in the (100) and (111) directions on a surface parallel to the mask at a depth of 1/5 of the plate thickness from the surface layer of the non-directional electromagnetic steel sheet. The ratio of I (100) and I (111) , which is the value of the ratio of the reflecting surface intensity to the random texture, is set within a predetermined range, and the (100) azimuth integration degree is set to the (111) azimuth integration degree near the surface layer of the steel sheet. By securing a certain amount or more, it is possible to suppress an increase in (111) orientation accumulation after grain growth due to strain removal and annealing. As a result, it is possible to provide a non-oriented electrical steel sheet having extremely excellent magnetic characteristics with almost no decrease in magnetic flux density after strain removal annealing.
[0009]
　On the other hand, in recent years, the number of motors that rotate at high speed (hereinafter referred to as high-speed rotation motors) has increased. In a high-speed rotary motor, the centrifugal force acting on a rotating body such as a rotor becomes large. Therefore, the electromagnetic steel sheet used as the material for the rotor of the high-speed rotary motor is required to have high strength.
[0010]
　Further, in a high-speed rotary motor, an eddy current is generated by a high-frequency magnetic flux, the motor efficiency is lowered, and heat is generated. When the amount of heat generated increases, the magnet in the rotor is demagnetized. Therefore, the rotor of a high-speed rotary motor is required to have a low iron loss. Therefore, the electrical steel sheet used as the material of the rotor is required to have not only high strength but also excellent magnetic properties.
　Patent Documents 2 to 8 propose non-oriented electrical steel sheets for the purpose of achieving both high strength and excellent magnetic properties.
　Patent Document 9 proposes a non-oriented electrical steel sheet capable of obtaining excellent magnetic properties in all directions in a plate surface.
Prior art literature
Patent documents
[0011]
Patent Document 1: Japanese Patent Application Laid-Open No. 8-134606
Patent Document 2: Japanese Patent Application Laid-Open No. 60-238421
Patent Document 3: Japanese Patent Application
Laid-Open No. 62-112723 Patent Document 4: Japanese Patent Application Laid-Open No. 2-22442
Patent Document 5: Japanese Patent Application Laid-Open No. 2-8346
Patent Document 6: Japanese Patent Application Laid-Open No. 2005-113185
Patent Document 7: Japanese Patent Application Laid-Open No. 2007-186790
Patent Document 8: Japanese Patent Application Laid-Open No. 2010-090474
Patent Document 9: International Publication No. 2018/220837 Gazette
Outline of the invention
Problems to be solved by the invention
[0012]
　The above-mentioned Patent Document 1 certainly has the effect of preventing a decrease in the magnetic flux density after strain removal and annealing, but describes the strength required for a material of a rotating body such as a rotor of a motor that rotates at high speed. There is no.
　Further, in the non-oriented electrical steel sheets disclosed in Patent Documents 1 to 8 described above, the characteristics after additional heat treatment such as strain relief annealing are not taken into consideration. As a result of the examination by the present inventors, when the non-oriented electrical steel sheets disclosed in these documents are subjected to additional heat treatment, the magnetic flux density may decrease.
　Further, in the non-oriented electrical steel sheet described in Patent Document 9 described above, since the average crystal grain size is relatively large, sufficient tensile strength cannot be obtained.
[0013]
　As described above, in the conventional technique, in a steel sheet having sufficient strength before strain annealing, it is possible to suppress a decrease in magnetic flux density due to strain annealing, sufficiently reduce iron loss, and obtain sufficient tensile strength. There was a challenge.
[0014]
　The present disclosure has been made in view of the above-mentioned problems. For example, in a non-oriented electrical steel sheet used for a drive motor or the like used in an automobile, a blank for a rotor having sufficient strength from one non-oriented electrical steel sheet and a blank for a rotor. An object of the present invention is to provide a non-oriented electrical steel sheet capable of producing a blank for a stator core having good magnetic characteristics (high magnetic flux density and low iron loss).
Means to solve problems
[0015]
　As a result of diligent studies, the present inventors have found that the ratio of the intensity to the random intensity in the {100} orientation of the 1/2 central layer (hereinafter, may be referred to as {100} intensity) is equal to or more than a predetermined value in the electrical steel sheet. For electrical steel sheets having a composition ratio of Si, Al, and Mn within a predetermined range, when strain-removal annealing is performed, the iron loss reduction effect due to strain-removal annealing and the magnetic flux density due to the increase in {100} strength are achieved. From the total effect of the improving effect and the iron loss reducing effect, it has been found that it is possible to obtain a significant iron loss reducing effect while improving the magnetic flux density, and the present invention has been completed.
[0016]
　That is, in the non-directional electromagnetic steel plate according to the present disclosure, C is 0.0030% by mass or less, Si is 2.0% by mass or more and 4.0% by mass or less, and Al is 0.010% by mass or more and 3.0% by mass. Hereinafter, Mn is 0.10% by mass or more and 2.4% by mass or less, P is 0.0050% by mass or more and 0.20% by mass or less, S is 0.0030% by mass or less, Mg, Ca, Sr, Ba, Ce. , La, Nd, Pr, Zn and Cd, containing one or more elements selected from the group in total of 0.00050% by mass or more, and having a chemical composition in which the balance is Fe and unavoidable impurities. When the mass% of Si is [Si], the mass% of Al is [Al], and the mass% of Mn is [Mn], the parameter Q represented by the following formula (1) is 2.0 or more, and { It is characterized in that it has a 100} strength of 2.4 or more and an average crystal grain size of 30 μm or less.
[0017]
Q = [Si] + 2 [Al]-[Mn] (1)
[0018]
　In the present disclosure, Sn is 0.02% by mass or more and 0.40% by mass or less, Cr is 0.02% by mass or more and 2.00% by mass or less, and Cu is 0.10% by mass or more and 2.00% by mass or less. It is preferable to contain at least one composition selected from the group consisting of.
[0019]
　Further, in the present disclosure, it is preferable to contain 5 or 10 μm 3 or more metal Cu particles having a diameter of 100 nm or less .
[0020]
　Further, in the present disclosure, the tensile strength is preferably 600 MPa or more.
The invention's effect
[0021]
　According to the present disclosure, it is possible to provide an electromagnetic steel sheet having high strength and high magnetic flux density and having a high effect of reducing iron loss during strain removing annealing.
A brief description of the drawing
[0022]
FIG. 1 is a graph showing the amount of decrease in iron loss in the examples.
Mode for carrying out the invention
[0023]
　Hereinafter, the non-oriented electrical steel sheet of the present disclosure and its manufacturing method will be described in detail.
　It should be noted that the terms such as "parallel", "vertical", and "same" and the values ​​of length and angle used in the present specification to specify the shape and geometric conditions and their degrees are strict. Without being bound by meaning, we will interpret it including the range in which similar functions can be expected.
[0024]
　The non-directional electromagnetic steel plate of the present disclosure contains C of 0.0030% by mass or less, Si of 2.0% by mass or more and 4.0% by mass or less, Al of 0.010% by mass or more and 3.0% by mass or less, and Mn. 0.10% by mass or more and 2.4% by mass or less, P: 0.0050% by mass or more and 0.20% by mass or less, S: 0.0030% by mass or less, Mg, Ca, Sr, Ba, Ce, La, It contains at least 0.00050 mass% of one or more elements selected from the group consisting of Nd, Pr, Zn and Cd in total, and the balance has a chemical composition consisting of Fe and unavoidable impurities, and the mass of Si. When% is [Si], mass% of Al is [Al], and mass% of Mn is [Mn], the parameter Q represented by the following formula (1) is 2.0 or more, and the strength is {100}. Is 2.4 or more, and the average crystal grain size is 30 μm or less.
[0025]
Q = [Si] + 2 [Al]-[Mn] (1)
[0026]
　Since the non-oriented electrical steel sheet of the present disclosure has an extremely high effect of reducing iron loss during strain relief annealing, a final product having high magnetic properties can be obtained. It is presumed that this is due to the following reasons.
[0027]
　That is, in the conventional non-oriented electrical steel sheet, when additional heating such as strain removal annealing is performed, it is less preferable in terms of magnetic properties than crystal grains having {100} or {411} orientation, which are considered to be good in magnetic properties. Although the growth of crystal grains having other orientations ({111} or {211}) is dominant and the iron loss is reduced due to the grain growth, the iron loss is reduced due to the increase in the texture due to the deterioration of the texture. It is presumed to be. Deterioration of the texture also causes a decrease in magnetic flux density.
　The non-oriented electrical steel sheet of the present disclosure has a parameter Q of 2 or more to make the steel sheet α-Fe single phase, and a {100} strength of 2.4 or more at the time of manufacturing the electrical steel sheet (that is, finishing). The crystal orientation after annealing and before strain-removal annealing) is advantageous for reducing iron loss, and the growth of other orientations is also dominant in the orientation development during slow-heating grain growth after additional heating such as strain-removal annealing. It is presumed that it promotes low iron loss while maintaining a high magnetic flux density.
[0028]
　In addition to this, by containing one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd, fine precipitates such as MnS (> By scavenging 1 μm), it has a favorable effect on the selective growth promotion of crystal grains having a crystal orientation advantageous for magnetic characteristics or the selective growth suppression of crystal grains having a crystal orientation unfavorable for magnetic characteristics. there is a possibility. That is, in the non-directional electromagnetic steel plate of the present disclosure having an oxide or acid sulfide containing the above-mentioned predetermined element group, the quenching temperature is set at the initial stage of recrystallization (the stage where the crystal grain size is 30 μm or less). Crystals generated at a relatively high heating rate while suppressing the crystal grain size by intentionally lowering the crystal are relatively low-heated at the grain growth stage (the stage where the crystal grain size exceeds 30 μm) in the latter stage of recrystallization. It is considered that the orientation selectivity is changed when the growth progresses at a rate.
[0029]
　It is considered that this makes it possible to suppress the decrease in the magnetic flux density when the strain is removed and annealed, and at the same time, to obtain a significant iron loss reduction effect and to have a high tensile strength.
[0030]
　In addition, regarding the present disclosure, a combination with other high-strength technology is also established. For example, a technique for increasing the strength by using a Cu single precipitate of 100 nm or less may be used in combination.
[0031]
　Hereinafter, each configuration of the non-oriented electrical steel sheet of the present disclosure will be described.
[0032]
1. 1. Chemical Composition
　First, the chemical composition of the non-oriented electrical steel sheet of the present disclosure will be described. The chemical composition described below is the composition of the steel components constituting the steel sheet. If the steel sheet used as the measurement sample has an insulating film or the like on its surface, it is the value obtained by removing it.
[0033]
(1) The CC
　content is 0.0030% by mass or less.
　If the C content is high, the austenite region is expanded, the phase transformation section is increased, and the grain growth of ferrite is suppressed during annealing, which may increase iron loss. Further, when magnetic aging occurs, the magnetic characteristics in a high magnetic field also deteriorate, so it is preferable to reduce the C content.
[0034]
　From the viewpoint of manufacturing cost, it is advantageous to reduce the C content by degassing equipment (for example, RH vacuum degassing equipment) at the molten steel stage, and if the C content is 0.0030% by mass or less, the magnetic aging is suppressed. The effect is great. Since the non-oriented electrical steel sheet according to the present disclosure does not use non-metal precipitates such as carbides as the main means for increasing the strength, there is no merit of intentionally containing C, and it is preferable that the C content is low. Therefore, the C content is preferably 0.0015% by mass or less, and more preferably 0.0012% by mass or less. By using a technique such as electrodeposition, it is possible to reduce the content to 0.0001% by mass or less, which is below the limit of chemical analysis, and the C content may be 0% by mass. On the other hand, considering the industrial cost, the lower limit is 0.0003% by mass.
[0035]
(2) Si The
　Si content is 2.0% by mass or more and 4.0% by mass or less.
　The Si content is a major element added to increase the resistivity and reduce the eddy current loss. If the Si content is low, it is difficult to obtain the effect of reducing the eddy current loss, and if it is high, the steel sheet may break during cold rolling.
[0036]
(3) The Al
　Al content is 0.010% by mass or more and 3.0% by mass or less.
　Al content is an element that is inevitably added to deoxidize steel in the steelmaking process, and is added to obtain the effect of increasing specific resistance and reducing eddy current loss, similar to Si. It is a major element. Therefore, Al is added in a large amount in order to reduce the iron loss, but when it is added in a large amount, the saturation magnetic flux density is reduced. In the present disclosure, it is necessary to set the parameter Q, which will be described later, to 2 or more and to form an α-Fe single layer.
[0037]
(4) Mn The
　Mn content is 0.10% by mass or more and 2.4% by mass or less.
　Mn may be positively added in order to increase the strength of the steel, but is not particularly required for this purpose in the present disclosure in which Cu fine particles are utilized as the main means for increasing the strength. It is added for the purpose of reducing iron loss by increasing the intrinsic resistance or coarsening the sulfide to promote crystal grain growth, but excessive addition lowers the magnetic flux density.
[0038]
(5) The
　PP content is 0.0050% by mass or more and 0.20% by mass or less.
　P is an element having a remarkable effect of increasing tensile strength, but like Mn described above, it is not necessary to add P intentionally for this purpose in the present disclosure. P increases the specific resistance to reduce the iron loss, and by segregating at the grain boundaries, suppresses the formation of a {111} texture that is disadvantageous to the magnetic characteristics, and {100} aggregates that are advantageous to the magnetic characteristics. It is added because it promotes the formation of tissue. On the other hand, excessive addition makes the steel embrittlement and reduces cold ductility and product workability.
[0039]
(6)
　The content of SS is 0.0030% by mass or less.
　S may be combined with Mn in steel to be generated as MnS. There is a concern that MnS may be finely precipitated (> 100 μm) in the steel manufacturing process to suppress grain growth during strain relief annealing. Therefore
, the produced sulfide may deteriorate the magnetic properties, particularly the iron loss, so that the S content is preferably as low as possible. It is preferably 0.0020 mass or less, more preferably 0.0010 mass or less.
[0040]
(7) The
　total amount of one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd is 0.00050 mass% or more.
　By containing 0.00050 mass% or more of these elements in total, precipitates having S and a high melting point are formed, and the formation of fine MnS in the steel is suppressed. It also enhances the effect of directional selectivity during strain removal annealing. On the other hand, even if it is added excessively, not only the effect of the invention is saturated, but also precipitates are formed, which hinders the movement of the domain wall and inhibits the grain growth, which may deteriorate the iron loss. Therefore, the upper limit is set to 0. It is 10% by mass.
[0041]
(8) Sn, Cr, and Cu In the
　present disclosure, Sn is 0.02% by mass or more and 0.40% by mass or less, Cr is 0.02% by mass or more and 2.00% by mass or less, and Cu is 0.10. It is preferable to have at least one composition selected from the group consisting of mass% or more and 2.00 mass% or less. Sn, Cr and Cu develop crystals suitable for improving magnetic properties by primary recrystallization. Therefore, when Sn, Cr or Cu is contained, a texture in which {100} crystals suitable for uniformly improving the magnetic properties in all directions in the plate surface are developed can be easily obtained by primary recrystallization. Further, Sn, Cr and Cu suppress oxidation and nitriding of the surface of the steel sheet during finish annealing, and suppress variations in crystal grain size. Therefore, Sn, Cr or Cu may be contained.
[0042]
(9) Remaining The
　balance is Fe and unavoidable impurities. Of the unavoidable impurities, Nb, Zr, Mo, V and the like are elements that form carbonitrides, so it is desirable to reduce them as much as possible, and their contents are preferably 0.01 mass or less. ..
[0043]
(10) Others In the
　present disclosure, when the mass% of Si is [Si], the mass% of Al is [Al], and the mass% of Mn is [Mn], the parameter Q represented by the following formula (1) is used. Is 2.0 or more.
Q = [Si] + 2 [Al]-[Mn] (1)
　This is because the non-oriented electrical steel sheet of the present disclosure has an α-Fe single phase, and the grain growth property at the time of strain relief annealing is ensured. To do.
[0044]
2. {100} strength (ratio of {100} orientation of 1/2 central layer to random strength) In
　the non-oriented electrical steel sheets of the present disclosure, the {100} strength is 3 among those using 2.4 or more. .0 or more, particularly 3.5 or more is preferable. The upper limit is not particularly limited, but can be 30 or less.
　In the present disclosure, by having {100} strength within the above range, excellent magnetism in which the magnetic flux density is not lowered and the iron loss is significantly reduced when additional heat treatment such as strain relief annealing is performed. It can be a non-oriented electrical steel sheet having characteristics.
[0045]
　The {100} intensity, that is, the X-ray random intensity ratio of the α-Fe phase of {100} can be obtained from the reverse pole figure measured and calculated by X-ray diffraction.
[0046]
　The random intensity ratio is the X-ray intensity of the standard sample and the test material that do not accumulate in a specific orientation under the same conditions, and the X-ray intensity of the obtained test material is the X-ray intensity of the standard sample. It is the value divided by the intensity.
　The measurement is performed at the position of 1/2 layer of the sample plate thickness. At that time, the measurement surface is finished by chemical polishing or the like so as to be smooth.
[0047]
3. 3. Particle size
　in the non-oriented electrical steel sheet of the present disclosure, the crystal grain size is 30μm or less, preferably 25μm or less, more preferably 15μm or less. The lower limit is preferably 3 μm or more, and particularly preferably 15 μm or more. When the crystal grain size is larger than the above range, the improvement in the value of iron loss due to strain relief annealing is small, and as a result, the magnetic properties of the member after strain removal annealing are deteriorated. On the other hand, if it is smaller than the above range, the value of iron loss of the member that is not subjected to strain removing and annealing becomes large. Further, if the crystal grain size exceeds 30 μm, the tensile strength decreases and the desired tensile strength cannot be obtained. In the non-oriented electrical steel sheet of the present disclosure, the tensile strength is increased to 600 MPa or more and high strength is achieved by reducing the crystal grain size to 30 μm or less. It is considered that the reason why the tensile strength increases when the crystal grains are fine is as follows. Tensile strength increases when dislocations (grid shifts) in steel become difficult to move. It is also known that when dislocations reach the grain boundaries, they become difficult to move. That is, if the grain boundaries are increased, in other words, the crystal grains are made finer, the tensile strength is improved.
[0048]
　The crystal particle size is an average particle size and can be obtained by the following measuring method.
　That is, a sample having a cross section parallel to the rolled surface of the non-oriented electrical steel sheet is prepared by polishing or the like. After adjusting the surface of the polished surface of the sample (hereinafter referred to as the observation surface) by electrolytic polishing, crystal structure analysis using electron backscatter diffraction (EBSD) is performed.
　According to EBSD analysis, the boundary where the crystal orientation difference is 15 ° or more is defined as the crystal grain boundary, and each region surrounded by the crystal grain boundary is defined as one crystal grain, and contains 10,000 or more crystal grains. Observe the area (observation area). In the observation region, the diameter (circle-equivalent diameter) when the crystal grains have an area equivalent to a circle is defined as the particle size. That is, the particle size means the diameter equivalent to a circle.
[0049]
4. Metal Cu Particles
　The non-oriented electrical steel sheet of the present disclosure may contain 5 or 10 μm 2 or more metal Cu particles having a diameter of 100 nm or less .
　In the present disclosure, it is presumed that having the above-mentioned metallic Cu particles enhances the strength of the non-oriented electrical steel sheet of the present disclosure and also contributes to the improvement of the magnetic properties at the time of strain removal annealing.
　In the present disclosure, as described above, the diameter of the metal Cu particles is 100 nm or less, and more preferably in the range of 1 nm to 20 nm, particularly preferably in the range of 3 nm to 10 nm. If it is larger than the above range, the efficiency of increasing the strength is remarkably lowered, and a large amount of Cu is required, so that the adverse effect on the magnetic characteristics becomes large. On the other hand, if it is smaller than the above range, the adverse effect on the magnetic characteristics becomes large, which is not preferable. The diameter of the metal Cu particles can be quantified by observation with an electron microscope. The diameter of the metal Cu particles also means the diameter equivalent to a circle.
[0050]
　The number density of the metal Cu particles, 5/10 [mu] m 2 or more, among them, 100/10 [mu] m 2 or more, in particular, 1,000 / 10 [mu] m 2 preferably more. If it is within the above range, it is effective in terms of increasing the strength.
　The number density of the metal Cu particles is determined by measuring oxides in a field of view of 10 μm × 10 μm using the same sample and averaging the measured values ​​of at least 5 fields of view.
[0051]
　In order to form the metal Cu particles in the present disclosure in the steel sheet, it is important to undergo the following thermal history. That is, in the process of manufacturing the product board, the product board is held in a temperature range of 450 ° C. to 720 ° C. for 30 seconds or longer. Further, in the subsequent steps, it is preferable not to hold the temperature in a temperature range exceeding 800 ° C. for 20 seconds or longer.
[0052]
　Through such a process, metallic Cu particles characteristic in diameter and number density are efficiently formed, and high strength can be achieved with almost no loss of magnetic properties.
　Since the strength of the steel material is increased after this heat treatment step, it is a viewpoint of productivity that this heat treatment step is performed after the rolling step and at the same time as the heat treatment required for other purposes such as recrystallization annealing. It is advantageous from. That is, in the case of a cold-rolled electromagnetic steel plate, the final heat treatment step after cold rolling, and in the case of a hot-rolled electromagnetic steel plate, in the final heat treatment step after hot rolling, in the cooling process from a temperature range of 750 ° C. or higher, 450 ° C. to 720 ° C. to 720. It is preferable to hold the product in a temperature range of ° C. for 30 seconds or longer.
[0053]
　Further, heat treatment may be applied depending on the desired characteristics and the like, but in that case, it is preferable not to hold the heat treatment in a temperature range exceeding 800 ° C. for 20 seconds or longer. This is because if the heat treatment is performed so that the temperature or time exceeds this, the formed Cu metal phase may be re-solidified or conversely aggregated to form a coarse metal phase.
　Since this disclosure does not utilize the strengthening by refining the crystal structure, the strain introduced into the material when punching the steel sheet and processing it into motor parts is recovered, and the crystal grains are grown to recover and improve the magnetism. Even if SRA (strain removal annealing) is applied for this purpose, it has the effect that the deterioration of strength is small.
[0054]
5. Other
　non-oriented electrical steel sheets of the present disclosure may further have an insulating film on the surface of the steel sheet.
　The insulating film in the present disclosure is not particularly limited, and can be appropriately selected and used from known ones according to the intended use, and may be either an organic film or an inorganic film. Examples of the organic film include polyamine resin, acrylic resin, acrylic styrene resin, alkyd resin, polyester resin, silicone resin, fluororesin, polyolefin resin, styrene resin, vinyl acetate resin, epoxy resin, phenol resin, urethane resin, and melamine. Examples include resin. Examples of the inorganic film include a phosphate film, an aluminum phosphate film, and an organic-inorganic composite film containing the above resin.
[0055]
　The thickness of the insulating film is not particularly limited, but the film thickness per side is preferably 0.05 μm or more and 2 μm or less.
　The method for forming the insulating film is not particularly limited. For example, a composition for forming an insulating film in which the above resin or an inorganic substance is dissolved in a solvent is prepared, and the composition for forming the insulating film is uniformly applied to the surface of the steel sheet by a known method. An insulating film can be formed by applying to.
　The thickness of the electromagnetic steel sheet of the present disclosure may be appropriately adjusted according to the intended use and is not particularly limited, but is usually 0.10 mm or more and 0.60 mm or less, and 0.015 mm from the viewpoint of manufacturing. More preferably 0.50 mm or less. From the viewpoint of the balance between magnetic characteristics and productivity, 0.015 mm or more and 0.35 mm or less is preferable.
[0056]
　The electromagnetic steel sheets of the present disclosure are particularly suitable for applications in which they are punched into an arbitrary shape. For example, servo motors and stepping motors used in electrical equipment, compressors in electrical equipment, motors used in industrial applications, electric vehicles, hybrid cars, drive motors for trains, generators and iron cores used in various applications, chokes. Any of conventionally known applications in which an electromagnetic steel plate is used, such as a coil, a reactor, and a current sensor, can be suitably applied.
　Above all, in the present disclosure, it can be suitably used for a rotor motor core and a stator motor core, which will be described later.
[0057]
6. Method for manufacturing grain-oriented electrical steel sheet The method for manufacturing grain-oriented electrical steel sheet of
　the present disclosure described above is not particularly limited, but the following (1) high-temperature hot-rolled sheet annealing + cold-rolled strong rolling method, Examples thereof include (2) thin slab continuous casting method, (3) lubrication hot rolling method, and (4) strip casting method.
　In any of the methods, the chemical composition of the starting material such as the slab is the chemical composition described in the above item "A. Non-oriented electrical steel sheet 1. Chemical composition".
[0058]
(1) High-temperature hot-rolled plate annealing + cold-rolled strong-pressing method
　First, a slab is manufactured in the steelmaking process. After heating the slab in a reheating furnace, it is continuously rough-rolled and finish-rolled in a hot rolling step to obtain a hot-rolled coil. The hot spreading conditions are not particularly limited. A general manufacturing method, that is, a manufacturing method in which a slab heated to 1000 to 1200 ° C. is finished by finishing heat spreading at 700 to 900 ° C. and wound up at 500 to 700 ° C. may be used.
[0059]
　Next, the hot-rolled sheet is annealed with respect to the steel plate of the hot-rolled coil. It is recrystallized by hot-rolled sheet annealing, and the crystal grains are coarsely grown to a crystal grain size of 300 to 500 μm.
　The hot-rolled sheet annealing may be continuous annealing or batch annealing. From the viewpoint of cost, the hot-rolled sheet annealing is preferably carried out by continuous annealing. In order to carry out continuous annealing, it is necessary to grow crystal grains at high temperature for a short time, and by setting the content of Si etc. to parameter Q ≧ 2.0, it is necessary to make it a component that does not cause ferrite-austenite transformation at high temperature. Can be done. In the case of continuous annealing, the hot-rolled sheet annealing temperature can be set to, for example, 1050 ° C.
[0060]
　Next, the steel sheet is pickled before cold rolling.
　Pickling is a process required to remove scale on the surface of the steel sheet. Pickling conditions are selected according to the situation of scale removal. Instead of pickling, the scale may be removed with a grinder.
[0061]
　Next, cold rolling is performed on the steel sheet.
　Here, in a high-grade non-oriented electrical steel sheet having a high Si content, if the crystal grain size is made too coarse, the steel sheet becomes brittle, and there is a concern about brittle fracture in cold rolling. Therefore, the average crystal grain size of the steel sheet before cold rolling is usually limited to 200 μm or less. On the other hand, in the present disclosure, the average crystal grain size before cold rolling is set to 300 to 500 μm, and the subsequent cold rolling is carried out at a rolling reduction of 88 to 97%.
　Instead of cold rolling, warm rolling may be carried out at a temperature equal to or higher than the ductility / brittle transition temperature of the material from the viewpoint of avoiding brittle fracture.
　After that, when finish annealing is carried out, ND // <100> recrystallized grains grow. As a result, the {100} surface strength increases, and the probability of existence of {100} oriented grains increases.
[0062]
　Next, finish annealing is performed on the steel sheet.
　The conditions for finish annealing need to be determined in order to obtain a crystal grain size capable of obtaining desired magnetic properties, but the finish annealing conditions may be within the range of ordinary non-oriented electrical steel sheet finish annealing conditions. However, in order to obtain fine crystal grains, a low temperature is desirable, and 800 ° C. or lower is desirable.
　The finish annealing may be continuous annealing or batch annealing. From the viewpoint of cost, it is preferable that the finish annealing is carried out by continuous annealing.
　Through the above steps, the non-oriented electrical steel sheet of the present disclosure described above can be obtained.
[0063]
(2) Thin slab continuous casting method In the
　thin slab continuous casting method, a slab having a thickness of 30 to 60 mm is manufactured in the steelmaking process, and rough rolling in the hot rolling process is omitted. It is desirable to sufficiently develop columnar crystals with a thin slab and leave the {100} <011> orientation obtained by processing the columnar crystals by hot rolling on the hot-rolled sheet. In this process, columnar crystals grow so that the {100} plane is parallel to the steel plate plane. For this purpose, it is desirable not to carry out electromagnetic agitation in continuous casting. In addition, it is desirable to reduce fine inclusions in molten steel that promote solidification nucleation as much as possible.
　Then, the thin slab is heated in a reheating furnace and then continuously finished and rolled in a hot rolling step to obtain a hot-rolled coil having a thickness of about 2 mm.
[0064]
　After that, the steel plate of the hot-rolled coil is subjected to hot-rolled sheet annealing, pickling, cold rolling, and finish annealing in the same manner as in the above "(1) High-temperature hot-rolled sheet annealing + cold-rolled strong compression method". ..
　Through the above steps, the non-oriented electrical steel sheet of the present disclosure described above can be obtained.
[0065]
　(3) Lubrication hot rolling method
　First, a slab is manufactured in the steelmaking process. After heating the slab in a reheating furnace, it is continuously rough-rolled and finish-rolled in a hot rolling step to obtain a hot-rolled coil.
　Here, hot rolling is usually carried out without lubrication, but hot rolling is performed under appropriate lubrication conditions. When hot rolling is performed under appropriate lubrication conditions, shear deformation introduced near the surface layer of the steel sheet is reduced. As a result, a processed structure having an RD // <011> orientation, which is usually called an α fiber that develops in the center of the steel sheet, can be developed near the surface layer of the steel sheet. For example, as described in Japanese Patent Application Laid-Open No. 10-36912, 0.5 to 20% of fats and oils are mixed in the hot-rolled roll cooling water as a lubricant during hot rolling, and the average friction coefficient between the finished hot-rolled roll and the steel sheet is By setting the value to 0.25 or less, the α fiber can be developed. The temperature condition at this time is not specified. The temperature may be the same as the above "(1) High temperature hot rolling plate annealing + cold rolling strong reduction method".
[0066]
　After that, the steel plate of the hot-rolled coil is subjected to hot-rolled sheet annealing, pickling, cold rolling, and finish annealing in the same manner as in the above "(1) High-temperature hot-rolled sheet annealing + cold-rolled strong compression method". .. When the α fiber is developed near the surface layer of the steel sheet with the steel sheet of the hot-rolled coil, {h11} <1 / h 12>, especially {100} <012> to {411} <148>, are obtained by the subsequent annealing of the hot-rolled sheet. Recrystallize. When this steel sheet is pickled, cold-rolled, and finish-annealed, {100} <012> to {411} <148> are recrystallized. As a result, the {100} surface strength increases, and the probability of existence of {100} oriented grains increases.
　Through the above steps, the non-oriented electrical steel sheet of the present disclosure described above can be obtained.
[0067]
(4) Strip casting method
　First, in the steelmaking process, a hot-rolled coil having a thickness of 1 to 3 mm is directly manufactured by strip casting.
　In strip casting, a steel plate having a thickness equivalent to that of a directly hot-rolled coil can be obtained by rapidly cooling the molten steel between a pair of water-cooled rolls. At that time, by sufficiently increasing the temperature difference between the outermost surface of the steel sheet in contact with the water-cooled roll and the molten steel, the crystal grains solidified on the surface grow in the vertical direction of the steel sheet to form columnar crystals.
[0068]
　In steel having a BCC structure, columnar crystals grow so that the {100} plane is parallel to the steel plate plane. The {100} surface strength increases, and the probability of existence of {100} orientation grains increases. Then, it is important that the {100} plane is not changed as much as possible by transformation, processing or recrystallization. Specifically, by containing Si, which is a ferrite-promoting element, and limiting the content of Mn, which is an austenite-promoting element, a ferrite single phase is formed from immediately after solidification to room temperature without undergoing austenite phase formation at high temperatures. Is important.
　Although a part of the {100} plane is maintained even if austenite-ferrite transformation occurs, by setting the content of Si etc. to parameter Q ≧ 2.0, it is possible to make a component that does not cause ferrite-austenite transformation at high temperature. Can be done.
[0069]
　Next, the steel plate of the hot-rolled coil obtained by strip casting is hot-rolled, and then the obtained hot-rolled plate is annealed (hot-rolled plate annealing).
　The hot rolling may not be carried out and the post-process may be carried out as it is.
　Further, the post-process may be carried out as it is without performing the hot-rolled plate annealing. Here, when a strain of 30% or more is introduced into the steel sheet by hot rolling, recrystallization may occur from the strain introduction portion and the crystal orientation may change when the hot-rolled sheet is annealed at a temperature of 550 ° C. or higher. Therefore, when a strain of 30% or more is introduced by hot rolling, hot-rolled sheet annealing is performed at a temperature at which it is not recrystallized or is not performed.
[0070]
　Next, the steel sheet is pickled and then cold-rolled.
　Cold rolling is an essential step in obtaining the desired product thickness. However, if the reduction rate of cold rolling becomes excessive, the desired crystal orientation cannot be obtained in the product. Therefore, the rolling reduction of cold rolling is preferably 90% or less, more preferably 85% or less, and further preferably 80% or less. The lower limit of the rolling reduction of cold rolling does not need to be set in particular, but the lower limit of the rolling reduction is determined from the thickness of the steel sheet before cold rolling and the desired product thickness. Further, even when the surface texture and flatness required for the laminated steel sheet are not obtained, cold rolling is required, so that the minimum cold rolling for that purpose is required.
　Cold rolling may be carried out in a reverse mill or a tandem mill.
[0071]
　Instead of cold rolling, warm rolling may be carried out at a temperature equal to or higher than the ductility / brittle transition temperature of the material from the viewpoint of avoiding brittle fracture.
　Pickling and finish annealing are carried out in the same manner as in the above "(1) High temperature hot rolling plate annealing + cold rolling strong compression method".
　Through the above steps, the non-oriented electrical steel sheet of the present disclosure described above can be obtained.
[0072]
　The present disclosure is not limited to the embodiments described above. The above-described embodiment is an example, and any object having substantially the same structure as the technical idea described in the claims of the present disclosure and exhibiting the same effect and effect is the present invention. Included in the technical scope of the disclosure.
Example
[0073]
　Hereinafter, the present disclosure will be specifically described by exemplifying examples. The conditions of the examples are examples adopted for confirming the feasibility and effect of the present disclosure, and the present disclosure is not limited to the conditions of the examples. This disclosure may adopt various conditions as long as it does not deviate from its gist and achieves its purpose.
[0074]
(Example 1)
　A 250 mm thick slab having the chemical composition shown in Table 1 below was prepared.
　Next, the slab was hot-rolled to prepare hot-rolled plates having a thickness of 5.0 mm and a thickness of 2.0 mm. At that time, the slab reheating temperature was 1200 ° C., the finishing temperature was 850 ° C., and the winding temperature was 650 ° C. The hot-rolled plate was annealed at 1050 ° C. for 30 minutes, and then the surface scale was removed by pickling. Then, it was cold-rolled to 0.25 mm. Finish annealing was performed at 750 ° C. and 1050 ° C. for 1 minute, respectively. A-38 to 40 were annealed at 600 ° C. for 1 minute after finish annealing as a Cu precipitation treatment.
[0075]
　The {100} texture, average crystal grain size, tensile strength, number of Cu precipitates, iron loss W10 / 400 and magnetic flux density B50 of the obtained non-oriented electrical steel sheet were measured. The {100} texture was obtained by calculating an inverse pole figure from X-ray diffraction. Iron loss W10 / 400 is an energy loss (W / kg) caused by iron when an alternating magnetic field of 1.0 T is applied at 400 Hz. The magnetic flux density B50 is the magnetic flux density generated in iron when a magnetic field of 5000 A / m is applied at 50 Hz. The measured values ​​were obtained by cutting a steel plate into a 55 mm square from the base metal (one side is the rolling direction), and taking the average value of the rolling direction and the 90 ° direction thereof.
[0076]
　After the above measurement, strain removal annealing is performed. Strain removal annealing is 100 ° C / Hr. In heated, 800 ° C. Itaru
Itarugo 2 hours soaked, 100 ℃ / Hr. Slowly cool with. However, the strain-removing annealing of the Cu-precipitated material was 100 ° C./Hr. After reaching 950 ° C, the temperature was equalized for 2 hours, and the temperature was adjusted to 100 ° C / Hr. Slowly cool with. After strain relief annealing, iron loss and magnetic flux density were measured in the same manner as above.
　In order to investigate the material strength before strain relief annealing, test pieces were collected in a direction parallel to the rolling direction and subjected to a tensile test. As the test piece at this time, the JIS No. 5 test piece was used. The maximum stress (tensile strength) until fracture was measured. The results of each measurement are shown in Table 2.
[0077]
　The material made from the 5.0 mm thick hot-rolled plate had a {100} strength greater than 2.4 after finish annealing (A1-40, A44-46, A50, A57-58). The {100} strength of the material made from the 2.0 mm thick hot-rolled plate after finish annealing was lower than 2.4 (A41-43, A47-49). The hot-rolled plates of A-51 to 56 were 5.0 mm thick, but the Q was less than 2.0, so the {100} strength was lower than 2.4 after finish annealing. The crystal grain size of the material finished and annealed at 750 ° C. was about 20 μm (A1 to 40, A47 to 57), and was about 100 μm at 1050 ° C. (A-41 to 46).
[0078]
　A-1 to 30 were changed to various additive elements. Regardless of which of the added elements was added, the effect of significantly reducing the iron loss after strain relief annealing was obtained. A-31 to 40 are those to which an optional additive element is added. Even if an optional element is added, the effect of significantly reducing iron loss during strain relief annealing does not change. For A-37 to 40, Cu was added as an optional additive element. Of these, A-38 to 40 are examples of inventions in which metal particles are precipitated. The average diameter and the number of precipitated metal Cu particles in A-38 to 40 are about 30 nm and about 100 particles / 10 μm 2 , respectively. By this precipitation treatment, when A-38 to 40 and Invention Examples A-1 to 3 having similar components are compared, A-1 and A-38, A-2 and A-39, and A-3 and A- In No. 40, it can be seen that the tensile strength is higher when each of them is subjected to the precipitation treatment. Therefore, by adding Cu as an optional additive element and performing the precipitation treatment of the metal particles, the effect of increasing the tensile strength can be obtained.
[0079]
　A-1 and 41 to 49 have almost the same components but different production conditions. Of these, FIG. 1 shows a graph summarizing the iron loss measurement results after SRA of A-1, 41, 44, and 47. {100} There is an effect of reducing iron loss by increasing the strength or making the crystal grains smaller before the strain annealing and making them coarser after the strain annealing, but when these two are combined, the strain is greatly distorted due to the synergistic effect. It can be seen that the iron loss after annealing can be reduced. Regarding the iron loss after strain relief annealing, the iron loss when Si is 2.0 to 2.3% is 9.5 W / kg or less, and the iron loss when Si is 2.4 to 3.1%. A pass level is defined as a loss of 9.0 W / kg or less and an iron loss of 8.5 W / kg or less when Si is 3.8 to 4.0%. Those having a higher iron loss than these are rejected because they can be reached without using the present invention.
[0080]
　It is considered that the reason why the iron loss decreases as the {100} strength increases is that the easy magnetization directions of the bcc iron are aligned in the plane, the leakage flux to the outside of the system is reduced, and the loss due to the domain wall movement is reduced. Further, even when the average crystal grain size after strain annealing is also about 100 μm, it is better to make the particle size finer after finish annealing and to 100 μm after strain annealing than to make this particle size by finish annealing. However, the iron loss became low. The reason for this is considered to be that the minute strain introduced during cooling during finish annealing was swept out by the movement of grain boundaries. It is presumed that the reason for the synergistic effect was that the {100} azimuth grains eclipsed the azimuth grains that were not good for other magnetic properties due to strain relief annealing.
　The characteristics when an element such as Mg that scavenges MnS is not added to A-50 are shown. Even if the strain was removed and annealed, the crystal grain size did not grow satisfactorily, and as a result, the iron loss became worse.
[0081]
　A-41, 42, 43 show comparative examples in which the {100} intensity is less than 2.4 and the particle size is more than 30 μm. Further, A-44, 45, 46, and 58 show comparative examples in which the {100} intensity is 2.4 or more, but the particle size is more than 30 μm. From these comparative examples, it can be seen that when the particle size exceeds 30 μm, sufficient tensile strength cannot be obtained.
[0082]
　Comparative examples in which Q is less than 2.0 are shown in A-51 to 56. In these comparative examples, since the steel sheet did not have an α-Fe single phase, the crystal grain size could not be coarsened during hot-rolled sheet annealing, and the {100} strength after finish annealing was lower than 2.4.
[0083]
[table 1]

[0084]
[Table 2]

[0085]
(Example 2)
　A 30 mm-thick slab having the chemical composition shown in Table 3 below and a 250 mm-thick slab were prepared. Next, the slab was hot-rolled to produce a hot-rolled plate having a thickness of 2.0 mm. At that time, the slab reheating temperature was 1200 ° C., the finishing temperature was 850 ° C., and the winding temperature was 650 ° C. Then, the surface scale was removed by pickling. Then, it was cold-rolled to 0.25 mm. Finish annealing was annealed at 750 ° C. for 1 minute. B-38-40 was annealed at 600 ° C. for 1 minute after finish annealing as a Cu precipitation treatment.
[0086]
　The {100} texture, average crystal grain size, tensile strength, number of Cu precipitates, iron loss W10 / 400 and magnetic flux density B50 of the obtained non-oriented electrical steel sheet were measured by the same method as in Example 1. Subsequent tensile tests and strain relief annealing were also carried out in the same manner as in Example 1. The results are shown in Table 4.
[0087]
　Materials made from 30 mm thick slabs had {100} strength greater than 2.4 after finish annealing (B-1 to B-40, B-44 to 46, B-50, B-57 to 58). ). Materials made from 250 mm thick slabs had {100} strength less than 2.4 after finish annealing (B-41-43, B47-49). The slabs of B-51 to 56 were 30 mm thick, but the Q was less than 2.0, so the {100} strength was lower than 2.4 after finish annealing. The crystal grain size of the material finished and annealed at 750 ° C. was about 20 μm (B-1 to 40, B-47 to 57), and was about 100 μm at 1050 ° C. (B-41 to 46).
[0088]
　B-1 to 30 were changed to various additive elements. Regardless of which of the added elements was added, the effect of significantly reducing the iron loss after strain relief annealing was obtained. B-31 to 40 are those to which an optional additive element is added. Even if an optional element is added, the effect of significantly reducing iron loss during strain relief annealing does not change. For B-37 to 40, Cu was added as an optional additive element. Of these, B-38 to 40 are examples of inventions in which metal particles are precipitated. The average diameter and the number of precipitated metal Cu particles in B-38 to 40 are about 30 nm and about 100 particles / 10 μm 2 , respectively. By this precipitation treatment, when B-38-40 and Invention Examples B-1 to 3 having similar components are compared, B-1 and B-38, B-2 and B-39, and B-3 and B- In No. 40, it can be seen that the tensile strength is higher when each of them is subjected to the precipitation treatment. Therefore, by adding Cu as an optional additive element and performing the precipitation treatment of the metal particles, the effect of increasing the tensile strength can be obtained.
[0089]
　B-1 and 41 to 49 have almost the same components but different production conditions. {100} There is an effect of reducing iron loss by increasing the strength or reducing the crystal grains before strain annealing and making them coarser after strain annealing, but when these two are combined, it becomes larger due to the synergistic effect. It can be seen that the iron loss after strain relief annealing can be reduced. Regarding the iron loss after strain relief annealing, the iron loss when Si is 2.0 to 2.3% is 9.5 W / kg or less, and the iron loss when Si is 2.4 to 3.1%. A pass level is defined as a loss of 9.0 W / kg or less and an iron loss of 8.5 W / kg or less when Si is 3.8 to 4.0%. Those having a higher iron loss than these are rejected because they can be reached without using the present invention.
[0090]
　The characteristics when an element such as Mg that scavenges MnS is not added to B-50 are shown. Even if the strain was removed and annealed, the crystal grain size did not grow satisfactorily, and as a result, the iron loss became worse.
[0091]
　B-41, 42, 43 show comparative examples in which the {100} intensity is less than 2.4 and the particle size is more than 30 μm. Further, B-44, 45, 46, and 58 show comparative examples in which the {100} intensity is 2.4 or more, but the particle size is more than 30 μm. From these comparative examples, it can be seen that when the particle size exceeds 30 μm, sufficient tensile strength cannot be obtained.
[0092]
　B-51 to 56 show comparative examples in which Q is less than 2.0. In these comparative examples, since the steel sheet does not have an α-Fe single phase, the structure formed by the thin slab is lost due to the phase transformation during slab reheating, and the {100} strength after finish annealing is higher than 2.4. It became low.
[0093]
[Table 3]

[0094]
[Table 4]

[0095]
(Example 3)
　A 250 mm thick slab having the chemical composition shown in Table 5 below was prepared.
　Next, the slab was hot-rolled to produce a hot-rolled plate having a thickness of 2.0 mm. At that time, the slab reheating temperature was 1200 ° C., the finishing temperature was 850 ° C., and the winding temperature was 650 ° C. Further, in order to improve the lubricity with the roll during hot spreading, 10% of oil and fat was mixed with the hot rolling roll cooling water as a lubricant, and the average friction coefficient between the finished hot rolling roll and the steel plate was set to 0.25 or less. In addition, some materials are hot-rolled without mixing fats and oils. Then, the surface scale was removed by pickling. Then, it was cold-rolled to 0.25 mm, and the finish annealing was annealed at 750 ° C. for 1 minute. C-38-40 was annealed at 600 ° C. for 1 minute after finish annealing as a Cu precipitation treatment.
[0096]
　The {100} texture, average crystal grain size, tensile strength, number of Cu precipitates, iron loss W10 / 400 and magnetic flux density B50 of the obtained non-oriented electrical steel sheet were measured by the same method as in Example 1. Subsequent tensile tests and strain relief annealing were also carried out in the same manner as in Example 1. The results are shown in Table 6.
[0097]
　The material mixed with oil and fat during hot rolling had a {100} strength greater than 2.4 after finish annealing (C-1 to 40, C44 to 46, C-50, C-57 to 58). The {100} strength after finish annealing of the material not mixed with oil and fat during hot rolling was lower than 2.4 (C-41 to 43, C47 to 49). C-51 to 56 were materials mixed with oils and fats during hot rolling, but since Q was less than 2.0, the {100} strength was lower than 2.4 after finish annealing. The crystal grain size of the material finished and annealed at 750 ° C. was about 20 μm (C-1 to 40, C-47 to 57), and was about 100 μm at 1050 ° C. (C-41 to 46).
[0098]
　C-1 to 30 were changed to various additive elements. Regardless of which of the added elements was added, the effect of significantly reducing the iron loss after strain relief annealing was obtained. C-31 to 40 are those to which an optional additive element is added. Even if an optional element is added, the effect of significantly reducing iron loss during strain relief annealing does not change. For C-37 to 40, Cu was added as an optional additive element. Of these, C-38 to 40 are examples of inventions in which metal particles are precipitated. The average diameter and the number of precipitated metal Cu particles in C-38 to 40 are about 30 nm and about 100 particles / 10 μm 2 , respectively. By this precipitation treatment, when C-38-40 and Invention Examples C-1-3 having similar components are compared, C-1 and C-38, C-2 and C-39, and C-3 and C- At 40, it can be seen that the tensile strength is higher when each of them is subjected to the precipitation treatment. Therefore, by adding Cu as an optional additive element and performing the precipitation treatment of the metal particles, the effect of increasing the tensile strength can be obtained.
[0099]
　C-1 and 41 to 49 have almost the same components but different production conditions. {100} There is an effect of reducing iron loss by increasing the strength or reducing the crystal grains before strain annealing and making them coarser after strain annealing, but when these two are combined, it becomes larger due to the synergistic effect. It can be seen that the iron loss after strain relief annealing can be reduced. Regarding the iron loss after strain relief annealing, the iron loss when Si is 2.0 to 2.3% is 9.5 W / kg or less, and the iron loss when Si is 2.4 to 3.1%. A pass level is defined as a loss of 9.0 W / kg or less and an iron loss of 8.5 W / kg or less when Si is 3.8 to 4.0%. Those having a higher iron loss than these are rejected because they can be reached without using the present invention.
[0100]
　The characteristics when an element such as Mg that scavenges MnS is not added to C-50 are shown. Even if the strain was removed and annealed, the crystal grain size did not grow satisfactorily, and as a result, the iron loss became worse.
[0101]
　C-41, 42, and 43 show comparative examples in which the {100} intensity is less than 2.4 but the particle size is more than 30 μm. Further, C-44, 45, 46, and 58 show comparative examples in which the {100} intensity is 2.4 or more, but the particle size is more than 30 μm. From these comparative examples, it can be seen that when the particle size exceeds 30 μm, sufficient tensile strength cannot be obtained.
[0102]
　Comparative examples in which Q is less than 2.0 are shown in C-51 to 56. In these comparative examples, since the steel sheet does not have an α-Fe single phase, γ phase is taken during lubrication rolling, and the effect of lubrication rolling disappears in the subsequent phase transformation, so the {100} strength after finish annealing is 2.4. Also became low.
[0103]
[Table 5]

[0104]
[Table 6]

[0105]
(Example 4)
　A 1.3 mm thick strip having the chemical composition shown in Table 7 below was cast. In addition to the strip casting described above, a slab cast with a slab thickness of 250 mm was hot-rolled, and the slab reheating temperature was 1200 ° C., the finishing temperature was 850 ° C., and the winding temperature was 650 ° C., which was hot-rolled to 2.0 mm. A steel plate was also used. Then, these steel sheets were pickled to remove the surface scale. Then, it was cold-rolled to 0.25 mm. Finish annealing was annealed at 750 ° C. for 1 minute. D-38-40 was annealed at 600 ° C. for 1 minute after finish annealing as a Cu precipitation treatment.
[0106]
　The {100} texture, average crystal grain size, tensile strength, number of Cu precipitates, iron loss W10 / 400 and magnetic flux density B50 of the obtained non-oriented electrical steel sheet were measured by the same method as in Example 1. Subsequent tensile tests and strain relief annealing were also carried out in the same manner as in Example 1. The results are shown in Table 8.
[0107]
　The strip-cast material had a {100} strength greater than 2.4 after finish annealing (D-1-40, D-44-46, D-50, D-57-58). The slab-cast material had a {100} strength after finish annealing of less than 2.4 (D-41-43, D-47-49). D-51-56 were strip-cast, but the Q was less than 2.0, so the {100} strength was lower than 2.4 after finish annealing. The crystal grain size of the material finished and annealed at 750 ° C. was about 20 μm (D-1 to 40, D-47 to 57), and was about 100 μm at 1050 ° C. (D-41 to 48).
[0108]
　D-1 to 30 were changed to various additive elements. Regardless of which of the added elements was added, the effect of significantly reducing the iron loss after strain relief annealing was obtained. D-31 to 40 are those to which an optional additive element is added. Even if an optional element is added, the effect of significantly reducing iron loss during strain relief annealing does not change. For D-37 to 40, Cu was added as an optional additive element. Of these, D-38 to 40 are examples of inventions in which metal particles are precipitated. The average diameter and the number of precipitated metal Cu particles in D-38 to 40 are about 30 nm and about 100 particles / 10 μm 2 , respectively. By this precipitation treatment, when D-38 to 40 and Invention Examples D-1 to 3 having similar components are compared, D-1 and D-38, D-2 and D-39, and D-3 and D- In No. 40, it can be seen that the tensile strength is higher when each of them is subjected to the precipitation treatment. Therefore, by adding Cu as an optional additive element and performing the precipitation treatment of the metal particles, the effect of increasing the tensile strength can be obtained.
[0109]
　D-1 and 41 to 49 have almost the same components but different production conditions. {100} There is an effect of reducing iron loss by increasing the strength or reducing the crystal grains before strain annealing and making them coarser after strain annealing, but when these two are combined, it becomes larger due to the synergistic effect. It can be seen that the iron loss after strain relief annealing can be reduced. Regarding the iron loss after strain relief annealing, the iron loss when Si is 2.0 to 2.3% is 9.5 W / kg or less, and the iron loss when Si is 2.4 to 3.1%. A pass level is defined as a loss of 9.0 W / kg or less and an iron loss of 8.5 W / kg or less when Si is 3.8 to 4.0%. Those having a higher iron loss than these are rejected because they can be reached without using the present invention.
[0110]
　The characteristics when an element such as Mg that scavenges MnS is not added to D-50 are shown. Even if the strain was removed and annealed, the crystal grain size did not grow satisfactorily, and as a result, the iron loss became worse.
[0111]
　D-41, 42, 43 show comparative examples in which the {100} intensity is less than 2.4 and the particle size is more than 30 μm. Further, D-44, 45, 46, 58 show a comparative example in which the {100} intensity is 2.4 or more, but the particle size is more than 30 μm. From these comparative examples, it can be seen that when the particle size exceeds 30 μm, sufficient tensile strength cannot be obtained.
[0112]
　D-51 to 56 show comparative examples in which Q is less than 2.0. In these comparative examples, since the steel sheet does not have an α-Fe single phase, the structure in the strip changes due to the phase transformation after strip casting, and the {100} strength after finish annealing is lower than 2.4.
[0113]
[Table 7]

[0114]
[Table 8]

WE CLAIM

[Claim 1]C is 0.0030% by mass or less, Si is 2.0% by mass or more and 4.0% by mass or less, Al is 0.010% by mass or more and 3.0% by mass or less, and Mn is 0.10% by mass or more and 2.4. % Mass% or less, P 0.0050% by mass or more and 0.20% by mass or less, S 0.0030% by mass or less, Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn and Cd. It contains at least 0.00050 mass% of one or more elements selected from the above, and has a chemical composition with the balance consisting of Fe and unavoidable impurities.
　Mass% of Si is [Si], mass% of Al When is [Al] and the mass% of Mn is [Mn], the parameter Q represented by the following formula (1) is 2.0 or more, and the
　ratio of random intensity to {100} orientation is 2.4 or more. A
　non-directional electromagnetic steel sheet having an average crystal grain size of 30 μm or less.
Q = [Si] + 2 [Al]-[Mn] (1)
[Claim 2]
　Select from the group consisting of Sn of 0.02% by mass or more and 0.40% by mass or less, Cr of 0.02% by mass or more and 2.00% by mass or less, and Cu of 0.10% by mass or more and 2.00% by mass or less. The non-directional electromagnetic steel sheet according to claim 1, which contains at least one composition.
[Claim 3]
The non-oriented electrical steel sheet according to claim 1 or 2 　, wherein the metal Cu particles having a diameter of 100 nm or less are contained in an amount of 5 particles / 10 μm 2 or more.
[Claim 4]
　The non-oriented electrical steel sheet according to any one of claims 1 to 3, which has a tensile strength of 600 MPa or more.