Title of invention: Non-oriented electrical steel sheet Technical field [0001] 　The present invention relates to non-oriented electrical steel sheets. 　The present application claims priority based on Japanese Patent Application No. 2018-056310 filed in Japan on March 23, 2018, the contents of which are incorporated herein by reference. Background technology [0002] 　In recent years, especially in the field of electrical equipment such as rotating machines, small and medium-sized transformers, and electrical components , in the movement to protect the global environment represented by global power reduction, energy saving, CO 2 emission reduction, etc. , The demand for higher efficiency and smaller size of motors is increasing more and more. In such a social environment, the performance of non-oriented electrical steel sheets used as the core material of motors is required to be improved. [0003] 　For example, in the field of automobiles, non-oriented electrical steel sheets are used as the core of a drive motor of a hybrid electric vehicle (HEV) or the like. The drive motors used in HEVs are in increasing demand for miniaturization due to restrictions on installation space and reduction of fuel consumption due to weight reduction. [0004] 　In order to reduce the size of the drive motor, it is necessary to increase the torque of the motor. Therefore, the non-oriented electrical steel sheet is required to further improve the magnetic flux density. [0005] 　In addition, since the battery capacity mounted on an automobile is limited, it is necessary to reduce the energy loss in the motor. Therefore, non-oriented electrical steel sheets are required to further reduce iron loss. [0006] 　Further, conventionally, an electromagnetic steel sheet may be used after being processed into a desired shape and then heat-treated. As a typical example, "Stress Relief Annealing (SRA)" is known. This is a heat treatment for finally removing unnecessary strain from the steel sheet because the strain unavoidably introduced into the steel sheet due to punching or the like when processing the steel sheet as an electrical component exacerbates the iron loss. .. This heat treatment is applied to a member (steel plate blank) cut out from a steel plate or a motor core (for example, a stator core) in which members are laminated. [0007] 　However, while strain relief annealing (SRA) has the effect of releasing strain and improving iron loss, it may also develop a crystal orientation that is unfavorable for magnetic properties and reduce the magnetic flux density. Therefore, when particularly high magnetic characteristics are required, it is required to avoid a decrease in magnetic flux density by strain annealing (SRA). [0008] 　Against this background, in the technology of non-directional electromagnetic steel sheets, various efforts have been made to control metal structures such as crystal grain size and crystal orientation in steel sheets, and control of precipitates, in order to improve magnetic properties. (See, for example, Patent Documents 1 to 13). Prior art literature Patent documents [0009] Patent Document 1: Japanese Patent Application Laid-Open No. 05-279740 Patent Document 2: Japanese Patent Application Laid-Open No. 06-306467 Patent Document 3: Japanese Patent Application Laid-Open No. 2002-348644 Patent Document 4: Japanese Patent Application Laid-Open No. 2011-1116858 JP Patent Document 5: Japanese Patent 2006-045613 JP Patent Document 6: Japanese Patent 2006-045641 JP Patent Document 7: Japanese Patent 2006-219692 JP Patent Document 8: Japanese Sho No. 58-23410 Patent Document 9: Japanese Patent Application Laid-Open No. 11-124626 Patent Document 10: International Publication No. 2012/029621 Patent Document 11: International Publication No. 2016/136095 Patent Document 12: Japanese Patent Application Laid- Open No. 03- No. 223424 Patent Document 13: International Publication No. 2014/129034 Outline of the invention Problems to be solved by the invention [0010] 　Here, Patent Document 1 describes a steel strip having a specific chemical composition containing 4.0% 　The silicon steel sheet of the non-oriented electrical steel sheet according to the present embodiment has a mass% of C: 0.0030% or less, Si: 0.01% to 3.50%, Al: 0. 0010% to 2.500%, Mn: 0.01% to 3.00%, P: 0.180% or less, S: 0.0030% or less, N: 0.0030% or less, B: 0.0020% It contains the following and has a chemical composition with the balance consisting of Fe and impurities. [0036] 　The non-oriented electrical steel sheet according to the present embodiment, the rolling direction when excited by magnetizing force 5000A / m, perpendicular to the rolling direction, and the average of the three directions of the rolling direction of 45 ° magnetic flux density B 50 of strain relief The difference in magnetic flux density before and after annealing may be 0.010 T or less. This will be described below. [0037] (Characteristics of precipitate distribution of 　silicon steel plate ) When the plate thickness of the silicon steel plate is t in the unit mm, the portion (1 / 10t portion) at the position 1/10 t in the plate thickness direction from the surface of the silicon steel plate, 1 / The PDR representing the ratio of the maximum value and the minimum value of the number density of AlN precipitates at three locations, the portion at the 5t position (1 / 5t portion) and the portion at the 1 / 2t position (1 / 2t portion), is 50. It is characterized by being less than%. 　PDR = (maximum value of number density among the above three locations-minimum value of number density among the above three locations) / minimum value of number density among the above three locations x 100 [0038] 　Specifically, the plate thickness of the silicon steel plate is t in units of mm, and the AlN number density out of three locations of 1/10 t part, 1/5 t part, and 1 / 2t part in the plate thickness direction from the surface of the silicon steel plate. When the maximum value of is expressed as NDmax in units: pieces / μm 2 and the minimum value is NDmin in units: pieces / μm 2 , and the AlN distribution state is expressed as PDR = (NDmax-NDmin) ÷ NDmin × 100 in units:%. PDR is 50% or less. [0039] 　The upper limit of the PDR is preferably 40%, more preferably 30% in order to make the AlN distribution state uniform. On the other hand, the lower limit of the PDR is not particularly limited and may be 0%. However, since it is not easy to control the lower limit of the PDR to 0%, the lower limit of the PDR may be 2% or 5%. [0040] 　There are many {111} recrystallized grains that deteriorate the magnetic flux density in 1 / 2t parts, and {100} recrystallized grains that improve the magnetic flux density in 1 / 10t parts. Since the conventional non-oriented electrical steel sheet had a small amount of AlN in the 1 / 2t portion, {111} recrystallized grains grew by strain annealing and deteriorated the magnetic flux density. In the present embodiment, it is possible to deposit AlN also in the 1 / 2t portion, and it becomes difficult to grow {111} recrystallized grains. Therefore, the deterioration allowance of the magnetic flux density due to strain annealing is suppressed to 0.010T or less. It is thought that it was. Therefore, the number density distribution of AlN precipitates in the plate thickness direction is defined as the PDR. [0041] 　AlN in the silicon steel plate can be measured by the following method. Mechanical polishing and chemical polishing are performed on the cross section of a steel sheet sample having a size of about 30 mm × 30 mm × 0.3 to 0.5 mm cut out from the steel sheet. The cross-section test piece is irradiated with an electron beam, and the obtained characteristic X-ray is detected by a microanalyzer to measure the number density of AlN. [0042] 　Specifically, the thickness of the silicon steel plate is t, and the plate surface of the test piece of about 30 mm × 30 mm cut out from the steel plate is thinned by mechanical polishing to make 1/10 t parts, 1/5 t parts, and 1 /. Each 2t part is exposed. These exposed surfaces are subjected to chemical polishing or electrolytic polishing to remove distortion and used as an observation test piece. Observe these exposed surfaces to confirm the presence or absence of AlN and the number of AlNs present. The number density can be obtained in units: pieces / μm 2 from the number of AlNs existing in the observation field of view (observation area) . [0043] 　In order to identify AlN present in the observation field, a precipitate having an atomic ratio of Al to N of approximately 1: 1 is observed in the observation field based on the quantitative analysis result of EPMA (Electron Probe Micro-Analyzer). You just have to specify. In addition, AlN existing in the observation field of view (observation area) may be specified, and the number density and the PDR may be obtained. [0044] 　A minute AlN that is difficult to identify by EPMA, for example, an AlN having a diameter smaller than 300 nm may be identified by using TEM-EDS (Transmission Electron Microscope-Energy Dispersive X-ray Spectroscopy). TEM observation test pieces (for example, about 15 mm × 15 mm) were collected from the 1 / 10t part, 1 / 5t part, and 1 / 2t part described above, and based on the quantitative analysis result of TEM-EDS, Al and N were added. Precipitates having an atomic ratio of approximately 1: 1 may be identified in the observation field. AlN existing in the observation field of view (observation area) may be specified, and the number density and the PDR may be obtained. [0045] (Chemical composition of silicon steel sheet) 　Next, the reason for limiting the chemical composition of the non-oriented electrical steel sheet according to the present embodiment in the silicon steel sheet will be described. Regarding the composition of the steel sheet, "%" is "mass%". [0046] 　In the present embodiment, the silicon steel sheet contains a basic element as a chemical composition, and if necessary, a selective element, and the balance is composed of Fe and impurities. [0047] 　The basic element means a major alloying element of a silicon steel plate. In this embodiment, the basic elements are Si, Al, and Mn. [0048] 　Further, the impurity means an element mixed from ore or scrap as a raw material, or from a manufacturing environment or the like when steel is industrially manufactured. For example, impurities are elements such as C, P, S, N, and B. It is preferable to limit the content of these impurities in order to fully exert the effects of the present embodiment. Further, since the content of impurities is preferably small, it is not necessary to limit the lower limit value, and the lower limit value of impurities may be 0%. [0049] 　Further, the selective element means an element that may be contained in place of a part of Fe, which is the balance described above. For example, it is an element such as Sn, Sb, Cu, REM, Ca, Mg and the like. These selective elements may be contained according to the purpose. Therefore, it is not necessary to limit the lower limit values ​​of these selective elements, and the lower limit value may be 0%. Further, even if these selective elements are contained as impurities, the above effects are not impaired. [0050] 　Specifically, the silicon steel plate of the non-directional electromagnetic steel plate according to the present embodiment has a mass% of C: 0.0030% or less, Si: 0.01% to 3.50%, Al: 0.0010%. ~ 2.500%, Mn: 0.01% ~ 3.00%, P: 0.180% or less, S: 0.0030% or less, N: 0.0030% or less, B: 0.0020% or less, Sb: 0 to 0.0500%, Sn: 0 to 0.2000%, Cu: 0 to 1.00%, REM: 0 to 0.0400%, Ca: 0 to 0.0400%, Mg: 0 to 0 It is preferable to have a chemical composition containing .0400% and the balance consisting of Fe and impurities. [0051] C: 0.0030% or less 　C (carbon) is a component that increases iron loss and is an impurity element that causes magnetic aging. Therefore, the smaller the C content, the better. Therefore, the content of C is set to 0.0030% or less. The preferred upper limit of the C content is 0.0025%, more preferably 0.0020%. The lower limit of the C content is not particularly limited, but practically, the C content is 0.0001% or more in consideration of the industrial purification technology, and 0.0005% or more in consideration of the manufacturing cost. .. [0052] Si: 0.01% to 3.50% When 　the content of Si (silicon) increases, the magnetic flux density decreases and the hardness increases, resulting in deterioration of punching workability. Further, in the manufacturing process of the non-oriented electrical steel sheet, workability such as cold rolling is lowered, the cost is high, and the possibility of breakage is high. Therefore, the upper limit of the Si content is 3.50%. The preferable upper limit of the Si content is 3.20%, and the more preferable upper limit is 3.00%. On the other hand, Si has the effect of increasing the electrical resistance of the steel sheet, reducing the eddy current loss, and reducing the iron loss. Therefore, the lower limit of the Si content is 0.01%. The preferable lower limit of the Si content is 0.10%, the more preferable lower limit is 0.50%, further preferably 1.00%, further preferably more than 2.00%, still more preferably 2.10%, still more preferably 2. It should be .30%. [0053] Al: 0.0010% to 2.500% 　Al (aluminum) is inevitably contained in ores and refractories, and is also used for deoxidation. Taking this into consideration, the lower limit is set to 0.0010%. Further, Al is a component having an action of reducing iron loss by increasing electric resistance and reducing eddy current loss, like Si. Therefore, Al may be contained in an amount of 0.200% or more. The Al content is preferably more than 0.50%, more preferably 0.60% or more. On the other hand, when the Al content increases, the saturation magnetic flux density decreases, which leads to a decrease in the magnetic flux density. Therefore, the upper limit of the Al content is 2.500%. It is preferably 2.000% or less. [0054] Mn: 0.01% to 3.00% 　Mn (manganese) increases electrical resistance to reduce eddy current loss and suppresses the formation of {111} <112> textures that are undesirable for magnetic properties. To do. For these purposes, Mn is contained in an amount of 0.01% or more. The lower limit of the Mn content is preferably 0.15%, more preferably 0.40%, further preferably more than 0.60%, still more preferably 0.70% or more. However, when the Mn content increases, the texture changes and the hysteresis loss deteriorates. Therefore, the upper limit of the Mn content is set to 3.00%. The preferred upper limit of the Mn content is 2.50%, more preferably 2.00%. [0055] P: 0.180% or less 　P (phosphorus) is an impurity element that impairs the toughness of steel and easily breaks the steel sheet, although it may increase the tensile strength without lowering the magnetic flux density. Therefore, the upper limit of the P content is 0.180%. The P content is preferably low in terms of suppressing the breakage of the steel sheet. The preferred upper limit of the P content is 0.150%, more preferably 0.120%, still more preferably 0.080%. The lower limit of the P content is not particularly limited, but is 0.001% in consideration of the manufacturing cost. [0056] S: 0.0030% or less 　S (sulfur) is an impurity element that inhibits recrystallization and grain growth during finish annealing and the like due to fine precipitation of sulfides such as MnS. Therefore, the S content is set to 0.0030% or less. The preferred upper limit of the S content is 0.0020%, more preferably 0.0015%. The lower limit of the S content is not particularly limited, but is 0.0001% in practical use in consideration of industrial purification technology, and 0.0005% in consideration of manufacturing cost. [0057] N: 0.0030% or less 　N (nitrogen) is an impurity element that forms a precipitate and deteriorates iron loss. Therefore, the N content is set to 0.0030% or less. It is preferably 0.002% or less, more preferably 0.001% or less. The lower limit of the N content is not particularly limited, but is 0.0001% in consideration of industrial purification technology and 0.0005% in consideration of manufacturing cost. [0058] B: 0.0020% or less 　B (boron) is an impurity element that forms a precipitate and deteriorates iron loss. Therefore, the B content is set to 0.0020% or less. It is preferably 0.001% or less, more preferably 0.0005% or less. The lower limit of the B content is not particularly limited, but is 0.0001% in consideration of industrial purification technology and 0.0005% in consideration of manufacturing cost. [0059] Sb: When 0 to 0.0500% 　Sb (antimony) is added, surface nitriding is suppressed and iron loss is also improved. On the other hand, excessive content of Sb deteriorates the toughness of steel. Therefore, the upper limit is set to 0.0500%. It is preferably 0.03% or less, more preferably 0.01% or less. The lower limit of Sb is not particularly limited and may be 0%. In order to obtain the above effect preferably, Sb may be 0.001% or more. [0060] Sn: 0 to 0.2000% When 　Sn (tin) is added, surface nitriding is suppressed and iron loss is also improved. On the other hand, the excessive content of Sn deteriorates the toughness of the steel and promotes the peeling of the insulating coating. Therefore, the upper limit is set to 0.2000%. The upper limit is preferably 0.08% or less, and more preferably 0.06% or less. The lower limit of Sn is not particularly limited and may be 0%. In order to obtain the above effect preferably, Sn may be 0.01% or more. It is preferably 0.04% or more, more preferably 0.08% or more. [0061] 　Cu: 0 to 1.00% 　Cu (copper) acts to suppress the formation of {111} <112> texture, which is not desirable for magnetic properties, controls the oxidation of the surface of the steel sheet, and grows crystal grains. It is an element that acts to sizing. When Cu exceeds 1.00%, the addition effect is saturated, the crystal grain growth during finish annealing is suppressed, the workability of the steel sheet is lowered, and the steel sheet becomes embrittled during cold rolling. Therefore, Cu is 1. It shall be 0.00% or less. It is preferably 0.60% or less, more preferably 0.40% or less. The lower limit of Cu is not particularly limited and may be 0%. In order to obtain the above effect preferably, Cu may be 0.10% or more. It is preferably 0.20% or more, more preferably 0.30% or more. [0062] 　REM: 0 to 0.0400%, 　Ca: 0 to 0.0400%, 　Mg: 0 to 0.0400% 　REM (Rare Earth Metal), Ca (calcium), Mg (magnesium) S is a sulfide or acid. It is an element that fixes as a sulfide, suppresses fine precipitation of MnS and the like, and promotes recrystallization and crystal grain growth during finish annealing. [0063] 　If REM, Ca, and Mg exceed 0.0400%, sulfide or acid sulfide is excessively generated, and recrystallization and grain growth during finish annealing are inhibited. Therefore, all of REM, Ca, and Mg are used. , 0.0400% or less. Preferably, each element is 0.0300% or less, more preferably 0.0200% or less. [0064] 　The lower limit of REM, Ca, and Mg is not particularly limited and may be 0%. In order to obtain the above effect preferably, all of REM, Ca and Mg may be 0.0005% or more. Preferably, each element is 0.0010% or more, more preferably 0.0050% or more. [0065] 　Here, REM refers to a total of 17 elements of Sc, Y and lanthanoid, and is at least one of them. The content of REM means the total content of at least one of these elements. In the case of lanthanoids, they are industrially added in the form of misch metal. [0066] 　In the present embodiment, the silicon steel plate has a chemical composition of Sb: 0.001 to 0.0500%, Sn: 0.01 to 0.2000%, Cu: 0.10 to 1.00% in mass%. It is preferable to contain at least one of REM: 0.0005 to 0.0400%, Ca: 0.0005 to 0.0400%, or Mg: 0.0005 to 0.0400%. [0067] 　The above chemical composition is the composition of a silicon steel plate. If the non-oriented electrical steel sheet to be the measurement sample has an insulating film or the like on the surface, the measurement is performed after removing the insulating film or the like. [0068] 　Examples of the method for removing the insulating coating of the non-oriented electrical steel sheet include the following methods. [0069] 　First, the non-directional electromagnetic steel plate having an insulating coating or the like is immersed in an aqueous solution of sodium hydroxide, an aqueous solution of sulfuric acid, and an aqueous solution of nitric acid in this order, and then washed. Finally, dry with warm air. As a result, it is possible to obtain a silicon steel plate from which the insulating film described later has been removed. [0070] 　The above-mentioned steel composition may be measured by a general method for analyzing steel. For example, the steel component may be measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Note that C and S may be measured using the combustion-infrared absorption method, N may be measured using the inert gas melting-thermal conductivity method, and O may be measured using the inert gas melting-non-dispersion infrared absorption method. [0071] (Magnetic Characteristics of Non-Directional Electromagnetic Steel Sheet) 　The non-directional electromagnetic steel plate according to the present embodiment has excellent magnetic characteristics for a motor core in three directions of rolling direction, rolling perpendicular direction, and rolling 45 ° direction. [0072] 　With respect to the average magnetic flux density B 50 in the above three directions when excited with a magnetization force of 5000 A / m, the deterioration allowance of the magnetic flux density B 50 due to strain annealing is preferably 0.010 T or less. [0073] 　Specifically, when the average of the magnetic flux density in the rolling direction, the magnetic flux density in the direction perpendicular to the rolling, and the magnetic flux density in the rolling 45 ° direction when excited with a magnetization force of 5000 A / m is the magnetic flux density B 50 , the strain is distorted. flux density before annealing preparative B 50 and the magnetic flux density B after stress relief annealing 50 the absolute value of the difference is preferably at most 0.010T. [0074] The difference in 　the magnetic flux density B 50 before and after strain relief annealing is preferably 0.008 T or less, more preferably 0.005 T or less, and further preferably 0.002 T or less. The lower limit of the difference in the magnetic flux density B 50 before and after strain relief annealing is not particularly limited, but may be 0. The lower limit may be closer to 0, for example, the lower limit may be 0.001T. [0075] 　There are many {111} recrystallized grains that deteriorate the magnetic flux density in 1 / 2t parts, and {100} recrystallized grains that improve the magnetic flux density in 1 / 10t parts. Since the conventional non-oriented electrical steel sheet had a small amount of AlN in the 1 / 2t portion, the {111} recrystallized grains were preferentially grown by strain annealing and the magnetic flux density was deteriorated. In the present embodiment, since it is possible to deposit AlN also in the 1 / 2t portion, the grain growth rates of the {100} grains and the {111} grains are relatively almost the same, so that after strain relief annealing. It is considered that the degree of accumulation of {100} grains was increased and the magnetic flux density deterioration allowance due to strain annealing was suppressed to 0.010 T or less. [0076] 　The magnetic properties of the electrical steel sheet may be measured based on the single plate magnetic property test method (Single Sheet Tester: SST) specified in JIS C 2556: 2015. In the 0 ° and 90 ° directions, for example, a sample of 55 mm square with respect to the rolling direction is cut and collected, and the magnetic flux density when the steel sheet is magnetized with a magnetization force of 5000 A / m in the direction perpendicular to the rolling direction and the rolling direction. Can be obtained by measuring with the unit: T (tesla). If it is in the 45 ° direction, a 55 mm square sample may be cut and collected in the 45 ° direction with respect to the rolling direction, the magnetic flux density may be measured in the length direction and the width direction of the test piece, and the average value of each may be obtained. .. Further, the iron loss W 15/50 when the steel sheet is magnetized at 50 Hz to a magnetic flux density of 1.5 T may be obtained. [0077] (Other Features of 　Non-oriented Electrical Steel Sheet) The thickness of the silicon steel sheet of the non-oriented electrical steel sheet according to the present embodiment may be appropriately adjusted according to the intended use and is not particularly limited. From the viewpoint of manufacturing, the average thickness of the silicon steel sheet is preferably 0.10 mm to 0.50 mm, preferably 0.15 mm to 0.50 mm. In particular, from the viewpoint of the balance between magnetic characteristics and productivity, the average thickness is preferably 0.15 mm to 0.35 mm. [0078] 　Further, the non-oriented electrical steel sheet according to the present embodiment may have an insulating film on the surface of the silicon steel sheet. The insulating coating formed on the surface of the non-oriented electrical steel sheet according to the present embodiment is not particularly limited, and may be selected from known ones according to the application and the like. [0079] 　For example, the insulating coating may be either an organic coating or an inorganic coating. 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; melamine. Examples include resin. [0080] 　Further, examples of the inorganic coating include a phosphate-based coating; an aluminum phosphate-based coating and the like. Further, an organic-inorganic composite coating containing the above resin can be mentioned. [0081] 　The average thickness of the insulating film is not particularly limited, but the average film thickness per one side is preferably 0.05 μm to 2 μm. [0082] 　As described above, the non-oriented electrical steel sheet according to the present embodiment is a hot-rolled sheet after finish hot-spreading, which has been performed for manufacturing a conventional non-oriented electrical steel sheet. Instead of annealing, it is obtained by performing a heat treatment that controls the temperature and time under specific conditions during cooling after hot spreading of finish, and further controlling the heating rate during finish annealing. [0083] 　FIG. 2 is a flow chart illustrating a method for manufacturing a non-oriented electrical steel sheet according to the present embodiment. In the present embodiment, molten steel having an adjusted composition is cast, hot-rolled, heat-treated at the time of cooling after hot-rolling, pickled, cold-rolled, and then finish-annealed to obtain a silicon steel sheet. To manufacture. Further, a non-oriented electrical steel sheet is manufactured by providing an insulating film on the upper layer of the silicon steel sheet. [0084] 　Hereinafter, an example of a preferable manufacturing method of the non-oriented electrical steel sheet according to the present embodiment will be described. [0085] 　An example of a suitable manufacturing method for the non-directional electromagnetic steel sheet of the present embodiment is C: 0.0030% or less, Si: 0.01% to 3.50%, Al: 0.0010% to 2 in mass%. .500%, Mn: 0.01% to 3.00%, P: 0.180% or less, S: 0.0030% or less, N: 0.0030% or less, B: 0.0020% or less, Sb: 0 to 0.0500%, Sn: 0 to 0.2000%, Cu: 0 to 1.00%, REM: 0 to 0.0400%, Ca: 0 to 0.0400%, Mg: 0 to 0.0400 A casting process for casting a slab containing% and the balance consisting of Fe and impurities, a hot rolling process for hot rolling (hot rolling) (hot rolling process), and a steel plate during cooling after hot rolling. A heat-retaining step of applying heat, a pickling step of pickling, a cold rolling step of cold rolling (cold rolling) (cold rolling step), and a finish annealing step of finish-rolling a steel plate after cold rolling Has. [0086] 　In the heat retention step, the heat retention temperature is controlled to 700 to 950 ° C. and the heat retention time is controlled to 10 minutes to 3 hours. In addition, in the finish annealing step, the average heating rate during heating is controlled to 30 to 200 ° C./sec. [0087] 　By satisfying both the two process conditions of the heat retention step and the finish annealing step, AlN precipitates at three locations of 1/10t part, 1 / 5t part, and 1 / 2t part in the plate thickness direction after finish annealing. A silicon steel plate having a PDR of 50% or less, which represents the distribution state of the above, can be obtained. As a result, as a non-oriented electrical steel sheet, the difference in magnetic flux density before and after strain removal annealing is suppressed to 0.010 T or less. [0088] 　The main steps will be described below. [0089] (Hot rolling process) Hot rolling 　is performed by heating a slab whose chemical composition has been adjusted. The heating temperature of the slab before hot spreading is not particularly limited, but it is preferably 1000 ° C. to 1300 ° C. from the viewpoint of cost and the like. [0090] 　After rough rolling on the heated slab, finish rolling is performed. At the time when the rough rolling is finished and the finish rolling is started, the thickness of the steel sheet is preferably 20 mm to 100 mm, and the final rolling temperature FT of the finish rolling is preferably 900 ° C. or higher, and 950 ° C. or higher. More desirable. By setting the final rolling temperature FT of the finish rolling to 950 ° C. or higher and making it easy for hot rolling shear strain to enter, the number of {100} recrystallized grains after finish annealing can be increased. [0091] (Heat retention process) The 　hot-rolled steel sheet is heat- retained during cooling after hot rolling. In the heat-retaining heat treatment, the heat-retaining temperature is 700 to 950 ° C., and the heat-retaining time (soaking time) is 10 minutes to 3 hours. By controlling both this heat treatment and finish annealing described later, the maximum value of the number density of AlN precipitates at three locations in the plate thickness direction of 1/10 t part, 1/5 t part, and 1 / 2t part can be obtained. The above-mentioned PDR, which is the ratio to the minimum value, is 50% or less. The reason why the heat retention condition affects the AlN precipitate is not clear, but it is considered as follows. [0092] 　In the conventional manufacturing method, the hot-rolled steel sheet is wound after the hot rolling process, the winding coil is cooled to room temperature without heat retention, and then the soaking temperature is 950 to 1050 ° C., and the soaking time is within 5 minutes. Then, the hot rolling sheet is annealed in an atmosphere in which nitrogen and hydrogen are mixed. In the hot-rolled annealed sheet annealed under this condition, AlN does not precipitate at the center of the steel sheet in the plate thickness direction. [0093] 　On the other hand, in the present embodiment, the hot-rolled steel sheet is held in an atmosphere containing a large amount of nitrogen in a temperature range of 700 to 950 ° C. for 10 minutes to 3 hours during cooling after hot rolling. Therefore, it is considered that nitrogen penetrates to the central portion in the plate thickness direction of the steel sheet, and AlN is likely to be precipitated at this central portion. In particular, the soaking time of the heat treatment is set to 10 minutes to 3 hours, and by performing annealing for a longer time than the conventional hot-rolled sheet annealing, AlN is uniformly precipitated from the surface of the steel sheet to the central portion in the plate thickness direction. It is thought that it can be done. [0094] 　For example, the soaking heat in the heat treatment may be carried out by winding the hot-rolled steel sheet after hot rolling and holding the wound coil in the coil cover or the coil box. At this time, the coil may be controlled so as to be held within the heat retention temperature. After the predetermined heat equalization time has elapsed, the coil may be taken out from the coil cover or the coil box to end the heat retention. [0095] (Cold rolling step) 　Next, after the heat treatment, the steel sheet is cooled to room temperature, and if necessary, the pickled steel sheet is cold-rolled. The reduction rate of cold rolling is not particularly limited. As a general condition, the total reduction rate in the cold rolling step (total reduction rate of cold rolling) may be 75% or more (preferably 80% or more, more preferably 85% or more). In particular, if a thin electromagnetic steel sheet is used, the total reduction ratio can be 90% or more. The total reduction ratio of cold rolling is preferably 95% or less in consideration of manufacturing control such as rolling mill capacity and plate thickness accuracy. [0096] (Finish annealing step) 　Next, the steel sheet after cold rolling is subjected to finish annealing. [0097] 　The average heating rate during heating of finish annealing is 30 to 200 ° C./sec. By controlling the average heating rate, it is the ratio of the maximum value and the minimum value of the number density of AlN precipitates at three locations of 1 / 10t part, 1 / 5t part, and 1 / 2t part in the plate thickness direction. The above PDR is 50% or less. The reason why the temperature rising condition affects the AlN precipitate is not clear, but it is considered as follows. [0098] 　In the conventional manufacturing method, the recrystallization structure and crystal grain size of the steel sheet are controlled, and the AlN number density in the steel is controlled, in particular, in the manufacturing method in which the heat treatment is performed during the cooling process after the hot rolling without annealing. The average rate of temperature rise during heating of the finish annealing was limited to less than 30 ° C./sec in order to preferably reduce the temperature. [0099] 　On the other hand, in the present embodiment, the average temperature rise rate during heating of finish annealing is controlled to 30 ° C./sec or more. It is considered that AlN in steel is easily melted during finish annealing and is particularly susceptible to the rate of temperature rise during heating. When the heating rate is less than 30 ° C./sec, AlN is easily melted, and in particular, AlN is non-uniformly melted according to the depth of the steel sheet, so that the uniformity of the AlN distribution in the thickness direction of the steel sheet is lost. By controlling the average heating rate during heating of the finish annealing to 30 ° C./sec or more, the PDR representing the distribution state of AlN can be preferably controlled. [0100] 　The average rate of temperature rise during heating of the finish annealing is preferably 40 ° C./sec or higher, and more preferably 50 ° C./sec or higher. The upper limit of the average temperature rise rate is not particularly limited, but may be set to 200 ° C./sec for stable operation. The upper limit of the average heating rate is preferably 100 ° C./sec. The average heating rate may be obtained based on the time required for heating from the heating start temperature (room temperature) to the soaking temperature described later. [0101] 　By setting the average heating rate during heating of the finish annealing to 30 to 200 ° C./sec, the degree of integration in the {100} orientation before the strain-removing annealing is increased, and the degree of integration in the {111} orientation is reduced. Therefore, the deterioration allowance of the magnetic flux density B 50 due to SRA becomes small. [0102] 　The soaking temperature of the finish annealing is preferably in the range of 800 ° C. to 1200 ° C. when the finish annealing has a sufficiently low iron loss. The soaking temperature may be a temperature equal to or higher than the recrystallization temperature, but by setting it to 800 ° C. or higher, sufficient grain growth can be caused and iron loss can be reduced. From this point of view, it is preferably 850 ° C. or higher. [0103] 　On the other hand, the upper limit of the soaking temperature is preferably 1200 ° C., preferably 1050 ° C. in consideration of the load of the annealing furnace. [0104] 　Further, the soaking time for finish annealing may be a time that takes into consideration the particle size, iron loss, magnetic flux density, strength, and the like, and can be, for example, 5 sec or more as a guide. On the other hand, if it is 120 sec or less, the crystal grain growth becomes appropriate. Therefore, the soaking time is preferably 5 sec to 120 sec. Within this range, for example, when grain growth is carried out by performing additional heat treatment by slow heating thereafter, a crystal orientation having an effect of avoiding inferior magnetic properties tends to remain. [0105] 　In addition, when additional heat treatment is finally performed by slow heating such as strain relief annealing (SRA), crystal grains grow and iron loss can be reduced, so there is no problem even if the soaking temperature of finish annealing is less than 800 ° C. Absent. In this case, the effect of avoiding the inferior magnetic flux density due to the additional heat treatment is remarkably exhibited. In this case, even if the unrecrystallized structure remains in a part, it is possible to have the characteristic crystal orientation of the non-oriented electrical steel sheet according to the present embodiment. Therefore, the lower limit temperature of the soaking temperature of the finish annealing may be, for example, 640 ° C. A steel sheet having a fine crystal structure or a partially unrecrystallized structure by lowering the soaking temperature of finish annealing has high strength, and is therefore useful as a high-strength non-directional electromagnetic steel sheet. [0106] 　In order to obtain the non-oriented electrical steel sheet according to the present embodiment, in addition to the above steps, insulation is provided on the surface of the silicon steel sheet after the finish annealing process, as in the conventional non-oriented electrical steel sheet manufacturing process. A film forming step may be provided. As each condition of the insulating film forming step, the same conditions as those of the conventional non-oriented electrical steel sheet manufacturing process may be adopted. [0107] 　The method for forming the insulating film is not particularly limited, but for example, a method for preparing an insulating film forming composition in which the above-mentioned resin or inorganic substance is dissolved in a solvent and applying the insulating film forming composition to the surface of a silicon steel plate is known. An insulating film can be formed by applying evenly with. [0108] 　The non-oriented electrical steel sheet according to the present embodiment can be obtained by the manufacturing method having the above steps. [0109] 　According to this embodiment, a non-oriented electrical steel sheet having excellent magnetic characteristics can be obtained. Therefore, the non-oriented electrical steel sheet according to the present embodiment can be suitably applied as a core material for various core materials of electric devices, particularly motors such as rotary machines, small and medium-sized transformers, and electrical components. Example 1 [0110] 　Next, the effect of one aspect of the present invention will be described in more detail by way of examples. However, the present invention is not limited to this one-condition example. In the present invention, various conditions can be adopted as long as the gist of the present invention is not deviated and the object of the present invention is achieved. [0111] A 　silicon steel sheet is manufactured from a slab whose chemical composition has been adjusted by controlling the manufacturing conditions in each step, and a phosphoric acid-based insulating film having an average thickness of 1 μm is formed on the silicon steel sheet. A non-oriented electrical steel sheet was manufactured. The chemical composition is shown in Tables 1 and 2, and the production conditions are shown in Tables 3 and 4. At the time of the above production, rough hot rolling was performed so that the thickness was 40 mm, and cold rolling was performed so that the plate thickness of the steel sheet after cold rolling was all 0.35 mm. [0112] 　The manufactured non-oriented electrical steel sheet was observed according to the method described above, and the distribution of AlN in the thickness direction of the silicon steel sheet was investigated. The results are shown in Tables 5 and 6. [0113] 　Further, the magnetic flux density B 50 was measured using the manufactured non-oriented electrical steel sheet . The average magnetic flux densities B 50 in the three directions of the rolling direction, the rolling perpendicular direction, and the rolling 45 ° direction before and after the strain annealing were obtained, and the difference ΔB 50 between before the strain annealing and after the strain annealing was obtained. A case where the average magnetic flux density B 50 before strain relief annealing was 1.58 T or more was passed, and a case where ΔB 50 was 0.010 T or less was passed. [0114] 　Here, the average magnetic flux density B 50 in the three directions of the rolling direction, the rolling perpendicular direction, and the rolling 45 ° direction is determined by the magnetic flux density when excited with a magnetization force of 5000 A / m. Specifically, there are three directions: a direction along the rolling direction (0 °), a direction perpendicular to the rolling direction (90 °), and a direction along the rolling direction and a direction inclined by 45 ° (45 °). The magnetic flux density may be measured and the average value in the three directions may be obtained. [0115] 　Further, the iron loss W 15/50 was measured using the manufactured non-oriented electrical steel sheet . 200 longitudinal definitive rolling direction of aging of ° C. × 2 hours, perpendicular to the rolling direction, and the average iron loss W of the three directions of the rolling direction of 45 ° 15/50 look, difference ΔW and after aging before and aging 15/50 to I asked. A case where the average iron loss W 15/50 before aging was 3.50 W / kg or less was passed, and a case where ΔW 15/50 was 0.4 W / kg or less was passed. [0116] 　The magnetic flux density and iron loss may be measured by the following methods. A 55 mm square sample is cut from a steel plate and collected, and B 50 (magnetic flux density of the steel plate when the steel plate is magnetized with a magnetization force of 5000 A / m, unit: T (tesla)) and W by Single Sheet Tester (SST). 15/50 (iron loss when the steel plate is magnetized to a magnetic flux density of 1.5 T at 50 Hz) may be measured. [0117] 　Tables 1 to 6 show the manufacturing conditions, manufacturing results, and evaluation results. The numbers underlined in the table indicate that they are outside the scope of the present invention. Further, in the table, "-" in the component composition of the silicon steel sheet indicates that the alloying element is not intentionally added or the content is below the measurement detection lower limit. [0118] 　As shown in the table, Test No. In the examples of the present invention of B1 to B19, since the component composition of the silicon steel sheet and the precipitation state of AlN were preferably controlled, they were excellent in magnetic properties as non-oriented electrical steel sheets. [0119] 　On the other hand, as shown in the table, the test No. In the comparative examples of b1 to b17, since either the component composition of the silicon steel sheet or the precipitation state of AlN was not preferably controlled, the magnetic properties of the non-oriented electrical steel sheet could not be satisfied. [0120] [table 1] [0121] [Table 2] [0122] [Table 3] [0123] [Table 4] [0124] [Table 5] [0125] [Table 6] Industrial applicability [0126] 　According to the non-oriented electrical steel sheet according to the above aspect of the present invention, it is possible to provide a non-oriented electrical steel sheet having a small change allowance of magnetic flux density before and after strain relief annealing (SRA). In particular, the rolling direction, perpendicular to the rolling direction, and the average of the three directions of the rolling direction of 45 °, the magnetic flux density B before stress relief annealing 50 magnetic flux density B and after stress relief annealing 50 difference is less than 0.010T Non-directional electromagnetic steel sheets can be provided. Therefore, it has high industrial applicability. Code description [0127] 　1 Non-oriented electrical steel sheet 　3 Silicon steel sheet (base steel sheet) 　5 Insulation film (tension film) 　11 Punched member 　13 Laminated body 　15 Teeth part 　17 Yoke part 　100 Motor core The scope of the claims [Claim 1] 　In the non-oriented electrical steel sheet provided with the silicon steel sheet and the insulating film, the 　silicon steel sheet has a chemical composition of 　　Si: 0.01% to 3.50% and 　　Al: 0.0010% to 2. 500%, 　　Mn: 0.01% to 3.00%, 　　C: 0.0030% or less, 　　P: 0.180% or less, 　　S: 0.0030% or less, 　　N: 0.0030% or less, 　　B: 0 It contains 0020% or less 　, the balance is Fe and impurities, and when 　the plate thickness of the silicon steel sheet is t, 1/10 t parts, 1/5 t parts, and 1 in the plate thickness direction from the surface of the silicon steel sheet. A non-oriented electrical steel sheet having a PDR of 50% or less according to the following (Equation 1), which represents the ratio of the maximum value and the minimum value of the number density of AlN precipitates at three locations in the / 2t portion . 　PDR = (maximum value-minimum value) / minimum value x 100 ... (Equation 1) [Claim 2] 　The silicon steel sheet, as a chemical composition, in mass%, 　　further, Sb: 0.0500% or 　　less, Sn: 0.0100% ~ 0.2000% 　contain at least one thing claim 1, wherein The non-oriented electrical steel sheet described. [Claim 3] 　The chemical composition of the silicon steel sheet is, in 　　terms of chemical composition, 　　Cu: 0 to 1.00%, REM: 0 to 0.0400%, 　　Ca: 0 to 0.0400%, 　　Mg: 0 to 0.0400%. 　The non-oriented electrical steel sheet according to claim 1 or 2, wherein the non-oriented electrical steel sheet contains at least one of .