Non-heat resistant magnetic domain refining treatment method and method for manufacturing non-heat resistant magnetic domain refined grain-oriented electrical steel sheet

Abstract

To provide a non-heat-resistant magnetic domain refining treatment method capable of predicting a leakage magnetic flux value of a grain-oriented electromagnetic steel sheet after applying magnetic domain refining treatment before applying the magnetic domain refining treatment to the grain-oriented electromagnetic steel sheet.SOLUTION: A non-heat-resistant magnetic domain refining method in which a grain-oriented electrical steel sheet is irradiated with an energy beam to perform non-heat-resistant magnetic domain refining treatment on the grain-oriented electrical steel sheet, the non-heat-resistant magnetic domain refining method comprising: A magnetic flux leakage value prediction step of predicting a magnetic flux leakage value of the grain-oriented electrical steel sheet after being subjected to the magnetic domain refining treatment using a magnetic flux leakage value prediction model learned by machine learning including one or more of surface state parameters of the grain-oriented electrical steel sheet before being subjected to the magnetic domain refining treatment, one or more of environmental condition parameters when being subjected to the magnetic domain refining treatment, and one or more of control parameters of an energy beam when being subjected to the magnetic domain refining treatment, and using the magnetic flux leakage value of the grain-oriented electrical steel sheet after being subjected to the magnetic domain refining treatment as output data.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a non-heat-resistant magnetic domain refinement treatment method and a method for producing a non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet. [Background technology]

[0002] Grain-oriented electrical steel sheets are primarily used as iron core materials in transformers. Low iron loss is required for grain-oriented electrical steel sheets, which are used as iron core materials. In addition to controlling the structure of grain-oriented electrical steel sheets, magnetic domain refinement processes that introduce thermal strain or linear grooves into the surface of grain-oriented electrical steel sheets are also used to reduce iron loss.

[0003] The linear grooves are introduced by a physical method such as using a gear roll, and the magnetic domain refining effect does not disappear even when heat treatment is performed, so this is called heat-resistant magnetic domain refining treatment (heat-resistant magnetic domain refining treatment). On the other hand, the thermal strain is introduced by irradiating the surface of the grain-oriented electrical steel sheet with an energy beam such as a laser, plasma, or electron beam. Magnetic domain refining treatment using thermal strain is also called non-heat-resistant magnetic domain refining treatment (non-heat-resistant magnetic domain refining treatment). By introducing thermal strain, magnetic poles are generated on the steel sheet surface, and magnetic domain refining is achieved.

[0004] In order to ensure stable production of grain-oriented electrical steel sheets that have been subjected to such non-heat-resistant magnetic domain refinement treatment (also referred to in this specification as non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheets), Patent Document 1 discloses a method for detecting leakage magnetic flux on the surface of the steel sheet and evaluating the processing state of the magnetic domain refinement treatment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-124266 Summary of the Invention [Problem to be solved by the invention]

[0006] The processing state of the magnetic domain refinement treatment of a non-heat-resistant, magnetic domain refined, grain-oriented electrical steel sheet can be evaluated by detecting the leakage flux value of the steel sheet using the technique described in Patent Document 1. However, there was no method for predicting the leakage flux value of a grain-oriented electrical steel sheet after the magnetic domain refinement treatment, before the grain-oriented electrical steel sheet is subjected to the magnetic domain refinement treatment.

[0007] An object of the present invention is to provide a non-heat-resistant magnetic domain refinement treatment method that can predict the leakage flux value of a grain-oriented electrical steel sheet after the magnetic domain refinement treatment, before the grain-oriented electrical steel sheet is subjected to the magnetic domain refinement treatment.

[0008] Another object of the present invention is to provide a method for producing a non-heat-resistant domain-refined grain-oriented electrical steel sheet using the non-heat-resistant magnetic domain refinement treatment method. [Means for solving the problem]

[0009] The present invention provides the following. [1] A non-heat-resistant magnetic domain refining method for irradiating a grain-oriented electrical steel sheet with an energy beam to perform a non-heat-resistant magnetic domain refining treatment on the grain-oriented electrical steel sheet, a leakage flux value prediction step of predicting the leakage flux value of the grain-oriented electrical steel sheet after the magnetic domain refinement treatment using a leakage flux value prediction model learned by machine learning, the input data of which includes one or more surface condition parameters related to the surface condition of the grain-oriented electrical steel sheet before the magnetic domain refinement treatment, one or more environmental condition parameters related to the environmental conditions when the magnetic domain refinement treatment is performed, and one or more control parameters related to the control conditions of the energy beam when the magnetic domain refinement treatment is performed, and the output data is the leakage flux value of the grain-oriented electrical steel sheet after the magnetic domain refinement treatment. [2] The non-heat-resistant magnetic domain refining method according to [1], further comprising a step of resetting the control parameters when the leakage flux value predicted in the leakage flux value prediction step falls outside a target range so that the leakage flux value falls within the target range. [3] A method for producing a non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet, comprising: subjecting a grain-oriented electrical steel sheet to a non-heat-resistant magnetic domain refinement treatment using the non-heat-resistant magnetic domain refinement treatment method according to [1] or [2] to produce a non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a non-heat-resistant magnetic domain refinement treatment method that can predict the leakage flux value of a grain-oriented electrical steel sheet after the magnetic domain refinement treatment, before the grain-oriented electrical steel sheet is subjected to the magnetic domain refinement treatment.

[0011] By being able to predict the leakage flux value of grain-oriented electrical steel sheet (non-heat-resistant, domain-refined grain-oriented electrical steel sheet) after magnetic domain refinement treatment before the magnetic domain refinement treatment is performed, the magnetic domain refinement treatment conditions can be optimized more quickly, allowing for more stable production of non-heat-resistant, domain-refined grain-oriented electrical steel sheet.

[0012] According to the present invention, the processing state of the magnetic domain refinement treatment is determined by the leakage flux value, and a prediction model for the leakage flux value is constructed that has learned the leakage flux value of the grain-oriented electrical steel sheet (non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet) after the magnetic domain refinement treatment, surface condition parameters related to the surface condition of the grain-oriented electrical steel sheet, environmental condition parameters related to the environmental conditions when the magnetic domain refinement treatment is performed, and control parameters related to the control conditions of the energy beam when the magnetic domain refinement treatment is performed, and if the leakage flux value predicted using the prediction model falls outside a predetermined range, the control parameters for the energy beam are adjusted, thereby making it possible to perform the magnetic domain refinement treatment more stably. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing an example of manufacturing equipment for a non-heat-resistant, domain-refined, grain-oriented electrical steel sheet. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of a leakage flux value prediction model generating device that generates a leakage flux value prediction model. [Figure 3]FIG. 3 is a block diagram showing an example of the configuration of a leakage magnetic flux value prediction device. [Figure 4] FIG. 4 is a diagram showing the relationship between the coil length and the leakage magnetic flux value when a non-heat-resistant, magnetic domain-refined, grain-oriented electrical steel sheet is manufactured in this example. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiment.

[0015] (Grain-oriented electrical steel sheet) First, in this embodiment, a grain-oriented electrical steel sheet to which a non-heat-resistant magnetic domain refinement treatment is applied will be described.

[0016] In this embodiment, the chemical composition of the slab for grain-oriented electrical steel sheet is not particularly limited as long as it is a chemical composition that allows secondary recrystallization. Furthermore, when an inhibitor is used, for example, when an AlN-based inhibitor is used, it is sufficient to add appropriate amounts of Al and N, and when an MnS·MnSe-based inhibitor is used, it is sufficient to add appropriate amounts of Mn and Se and / or S. Of course, both inhibitors may be used in combination. In this case, the preferred contents of Al, N, S, and Se are, respectively, 0.01 to 0.065 mass% Al, 0.005 to 0.012 mass% N, 0.005 to 0.03 mass% S, and 0.005 to 0.03 mass% Se.

[0017] Furthermore, grain-oriented electrical steel sheets may be those in which the contents of Al, N, S, and Se are limited and no inhibitor is used. In this case, the amounts of Al, N, S, and Se are preferably controlled to less than 100 ppm by mass of Al, less than 50 ppm by mass of N, less than 50 ppm by mass of S, and less than 50 ppm by mass of Se, respectively.

[0018] Next, the basic components and optional additional components of the slab for the grain-oriented electrical steel sheet will be specifically described.

[0019] C: 0.08% by mass or less C is added to improve the hot-rolled sheet structure. However, if the C content exceeds 0.08 mass%, it becomes difficult to reduce the C content to 50 mass ppm or less, at which point magnetic aging does not occur during the manufacturing process, so the C content is preferably 0.08 mass% or less. Note that there is no need to set a lower limit for the C content, as secondary recrystallization is possible even in materials that do not contain C. In other words, the C content may be 0 mass%. When C is added to improve the hot-rolled sheet structure, the C content is preferably 0.01 mass% or more.

[0020] Si:2.0~8.0% by mass Silicon is an element effective in increasing the electrical resistance of steel and improving iron loss, and for this reason, the Si content is preferably 2.0% by mass or more. On the other hand, if the Si content is 8.0% by mass or less, it becomes easier to prevent a decrease in workability and a decrease in magnetic flux density. Therefore, the Si content is preferably in the range of 2.0 to 8.0% by mass.

[0021] Mn:0.005~1.0% by mass Mn is an element necessary for improving hot workability, and therefore its content is preferably 0.005% by mass or more. On the other hand, if the Mn content is 1.0% by mass or less, it is easy to suppress a decrease in the magnetic flux density of the product sheet. Therefore, the Mn content is preferably in the range of 0.005 to 1.0% by mass.

[0022] The slab for grain-oriented electrical steel sheet preferably has the above-mentioned components as its basic components. In addition to the above-mentioned basic components, the slab may optionally contain the following elements. The following elements are effective in improving magnetic properties. One or more selected from Ni: 0.03 to 1.50 mass%, Sn: 0.01 to 1.50 mass%, Sb: 0.005 to 1.50 mass%, Cu: 0.03 to 3.0 mass%, P: 0.03 to 0.50 mass%, Mo: 0.005 to 0.10 mass%, and Cr: 0.03 to 1.50 mass%

[0023] Ni is an element useful for improving the hot-rolled sheet structure and enhancing magnetic properties, and it is preferable to contain 0.03% by mass or more of Ni. On the other hand, if the Ni content is 1.50% by mass or less, it is possible to prevent secondary recrystallization from becoming unstable, and it is easy to reduce the risk of deterioration of the magnetic properties of the product sheet. Therefore, if Ni is contained, the Ni content is preferably in the range of 0.03 to 1.50% by mass.

[0024] Furthermore, Sn, Sb, Cu, P, Mo, and Cr are also elements useful for improving magnetic properties, and when the content of each element is equal to or greater than the lower limit of the above-mentioned element, the effect of improving magnetic properties is more likely to be achieved. On the other hand, when the content of each element is equal to or less than the upper limit of the above-mentioned element, the risk of inhibiting the development of secondary recrystallized grains is more likely to be reduced. Therefore, when Sn, Sb, Cu, P, Mo, and Cr are contained, the content of each of the above elements is preferably set within the above-mentioned range.

[0025] The balance other than the above components is Fe and unavoidable impurities.

[0026] Next, a method for manufacturing grain-oriented electrical steel sheet will be described. A slab having the above-mentioned composition is heated in a conventional manner and subjected to hot rolling. In this case, the slab may be hot rolled immediately after casting without heating. In the case of a thin cast slab, hot rolling may be performed, or the hot rolling may be omitted and the slab may proceed directly to the subsequent steps.

[0027] Furthermore, if necessary, hot-rolled sheet annealing is performed. At this time, in order to highly develop the Goss structure in the product sheet, the hot-rolled sheet annealing temperature is preferably in the range of 800 to 1100°C. That is, if the hot-rolled sheet annealing temperature is less than 800°C, the band structure from hot rolling remains, making it difficult to realize a grain-regulated primary recrystallization structure, and the development of secondary recrystallization may be inhibited. On the other hand, if the hot-rolled sheet annealing temperature exceeds 1100°C, the grain size after hot-rolled sheet annealing becomes too coarse, making it extremely difficult to realize a grain-regulated primary recrystallization structure.

[0028] After annealing the hot-rolled sheet, it is cold-rolled once or twice or more times with intermediate annealing in between, then recrystallization annealing is performed and an annealing separator is applied. After the annealing separator is applied, final annealing is performed for the purpose of secondary recrystallization and the formation of a forsterite film.

[0029] After the final annealing, it is preferable to perform flattening annealing to correct the shape. Furthermore, it is preferable to apply a coating (insulation coating) to the surface of the steel sheet before or after the flattening annealing. This coating refers to a coating (tension coating) that can impart tension to the steel sheet to reduce iron loss. Examples of such coatings include inorganic coatings containing silica and ceramic coatings formed by physical vapor deposition, chemical vapor deposition, etc.

[0030] The above steps result in a grain-oriented electrical steel sheet that has been subjected to final annealing. Note that the steel sheet also includes a steel strip.

[0031] Thereafter, the grain-oriented electrical steel sheet that has been subjected to final annealing as described above can be inspected (inspection step of grain-oriented electrical steel sheet). In the inspection step, the surface condition of the grain-oriented electrical steel sheet may be inspected.

[0032] [Non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet manufacturing equipment] Next, an example of a manufacturing facility for a non-heat-resistant domain-refined grain-oriented electrical steel sheet to which the non-heat-resistant magnetic domain refinement method of this embodiment can be applied will be described.

[0033] FIG. 1 is a schematic diagram showing an example of a manufacturing facility for a non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet to which the non-heat-resistant magnetic domain refinement treatment method of this embodiment can be applied.

[0034] 1 is an example of a manufacturing facility 10 for producing a non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet, which performs a non-heat-resistant magnetic domain refinement treatment by irradiating a grain-oriented electrical steel sheet (steel sheet S) with an energy beam. The energy beam may be a high-energy beam such as a laser, plasma, or electron beam.

[0035] The steel sheet S is, for example, a grain-oriented electrical steel sheet that has been produced as described above and has been subjected to final annealing. The steel sheet S may have a coating applied to its surface.

[0036] The manufacturing equipment 10 shown in FIG. 1 includes a vacuum chamber 1. The vacuum chamber 1 is equipped with an exhaust system and an air conditioning system (not shown), and the internal environmental conditions, such as the degree of vacuum, temperature, and humidity, can be adjusted. The vacuum chamber 1 is also equipped with an energy beam irradiation device 3 (in this embodiment, an electron gun) that irradiates an energy beam onto a steel sheet S passing through the vacuum chamber 1. The energy beam irradiation device 3 includes, for example, a beam generation unit that generates a beam, a focusing coil that focuses the beam, and a polarization system that directs the beam onto the irradiated surface (the surface of the steel sheet S). The energy beam irradiation device 3 irradiates the surface of the steel sheet S with an energy beam in a streaky manner, and subjects the steel sheet S to a non-heat-resistant magnetic domain refining treatment.

[0037] The manufacturing equipment 10 is equipped with a payoff reel 4 upstream of the vacuum chamber 1 for discharging the steel sheet S, and a tension reel 5 downstream of the vacuum chamber 1 for winding up the steel sheet S (non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet) that has been subjected to non-heat-resistant magnetic domain refinement treatment in the vacuum chamber 1. The vacuum chamber 1 may also have differential pressure chambers on both its inlet and outlet sides. In this embodiment, a vacuum refers to a space with a pressure lower than atmospheric pressure. The pressure (degree of vacuum) within the vacuum chamber 1 can be adjusted as appropriate, but can be set to 1.0 Pa or less, for example.

[0038] An environmental measuring device 6 is installed in the vacuum chamber 1 to measure the environmental conditions within the vacuum chamber 1. The environmental measuring device 6 measures at least one environmental condition parameter related to the environmental conditions when the magnetic domain refining process is performed. In addition, a tension meter (not shown) is installed in the tension reel 5 to measure the tension applied to the steel sheet S by the payoff reel 4 and the tension reel 5.

[0039] A surface inspection device 8 is installed upstream of the vacuum chamber 1 to measure the surface condition of the steel sheet S. The surface inspection device 8 measures and acquires at least one surface condition parameter related to the surface condition of the steel sheet S. In addition, a leakage magnetic flux value measuring device 9 is installed downstream of the vacuum chamber 1 to measure the leakage magnetic flux value of the surface of the steel sheet S that has been subjected to non-heat-resistant magnetic domain refinement treatment in the vacuum chamber 1.

[0040] Examples of the environmental measuring device 6 include a vacuum gauge, a thermometer, a hygrometer, and a thermo-hygrometer. These environmental measuring devices are not particularly limited, and for example, known vacuum gauges, thermometers, hygrometers, and thermo-hygrometers can be used. One or more of these can be used as the environmental measuring device 6. The environmental measuring device 6 measures and acquires an environmental condition parameter related to at least one environmental condition, such as the degree of vacuum, temperature, and humidity, inside the vacuum chamber 1 when the magnetic domain refining process is performed. Note that in this embodiment, the tension (tension value) measured by the tensiometer may be used as the environmental condition parameter.

[0041] Examples of the surface inspection device 8 include a digital camera capable of measuring the color tone (brightness) of the surface of the steel sheet S, a roughness meter capable of measuring the surface roughness of the steel sheet S, an EPMA (electron probe microanalyzer) or AES (Auger electron spectroscopy) capable of measuring the oxide thickness on the surface of the steel sheet S or the amount of surface elements on the steel sheet S, and a film thickness meter capable of measuring the thickness of a coating formed on the surface of the steel sheet S. One or more of these can be used as the surface inspection device 8. The surface inspection device 8 measures and acquires at least one surface condition parameter related to the surface condition of the steel sheet S, such as the color tone (brightness), surface roughness, oxide thickness, amount of surface elements, and coating thickness of the grain-oriented electrical steel sheet (steel sheet S) before magnetic domain refinement treatment is performed.

[0042] In this embodiment, the surface inspection device 8 is installed upstream of the vacuum chamber 1 to measure the surface state parameters of the steel sheet S, but this is not limiting. For example, the surface inspection device 8 may measure and acquire the surface texture parameters of the steel sheet S in an inspection step (inspection step of the grain-oriented electrical steel sheet) after manufacturing the grain-oriented electrical steel sheet that has been subjected to the above-mentioned final finish annealing.

[0043] The leakage magnetic flux measurement device 9 may be, for example, the device described in Patent Document 1. The leakage magnetic flux measurement device 9 measures the leakage magnetic flux value of a grain-oriented electrical steel sheet (non-heat-resistant, magnetic domain refinement grain-oriented electrical steel sheet) after magnetic domain refinement treatment. When magnetic domain refinement treatment is performed by irradiating the surface of the steel sheet S with an energy beam in a streak-like manner from an energy beam irradiation device 3, a streak-like processed portion (magnetic domain refinement processed portion) is generated on the surface of the steel sheet S, which is modified by the energy beam irradiation. The leakage magnetic flux measurement device 9 measures the leakage magnetic flux value based on the processed state of such a magnetic domain refinement processed portion. As will be described later, in areas where the processing by the magnetic domain refinement treatment (processing to form the streak-like processed portion) is unstable or insufficient, the leakage magnetic flux value measured by the leakage magnetic flux measurement device 9 will be small.

[0044] [Leakage magnetic flux value prediction model generation device] Next, with reference to FIG. 2, an example of the configuration of a leakage flux value prediction model generating device that generates a leakage flux value prediction model that can be applied to the non-heat-resistant magnetic domain refining method of this embodiment will be described.

[0045] 2 is a block diagram showing an example of the configuration of a leakage flux value prediction model generating device that generates a leakage flux value prediction model that can be applied to the non-heat-resistant magnetic domain refining method of the present invention. The leakage flux value prediction model generating device 100 shown in FIG. 2 is configured by an information processing device such as a workstation or a personal computer, and includes a database 101 and a machine learning unit 102.

[0046] The database 101 is configured by a non-volatile storage device and stores actual data on surface condition parameters relating to the surface condition of the grain-oriented electrical steel sheet (steel sheet S) before the magnetic domain refinement treatment is performed, actual data on environmental condition parameters relating to the environmental conditions when the magnetic domain refinement treatment is performed, actual data on control parameters relating to the control conditions of the energy beam when the magnetic domain refinement treatment is performed, and actual data on the leakage magnetic flux value of the grain-oriented electrical steel sheet (non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet) after the magnetic domain refinement treatment is performed.

[0047] (Steel plate surface condition parameters) Surface condition parameters (also simply referred to as surface condition parameters in this specification) relating to the surface condition of the grain-oriented electrical steel sheet (steel sheet S) before magnetic domain refinement treatment can be acquired by a surface inspection device 8. The surface condition of the steel sheet S affects the processing state of the magnetic domain refinement processed portion when the steel sheet S is subjected to magnetic domain refinement treatment. In other words, it affects the leakage magnetic flux value of the grain-oriented electrical steel sheet (non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet) after magnetic domain refinement treatment.

[0048] Examples of the surface condition parameters of the steel sheet S include the color of the surface of the steel sheet S, the surface roughness of the steel sheet S, the oxide thickness on the surface of the steel sheet S, the amount of surface elements on the steel sheet S, and the thickness of the coating formed on the surface of the steel sheet S. At least one of these can be used as the surface condition parameter of the steel sheet S.

[0049] The surface color of the steel sheet S can be obtained, for example, by observing the surface of the steel sheet S using a digital camera as a surface inspection device 8 and measuring the color tone (brightness) of the observed image. The surface color of the steel sheet S varies depending on the conditions of the final annealing and coating when manufacturing the steel sheet S. For example, if a coating is formed on the surface of the steel sheet S, the damaged area will have a higher brightness than the undamaged area. In the damaged area, the processing state tends to become unstable when a magnetic domain refinement treatment is performed. Therefore, the surface color of the steel sheet S affects the leakage magnetic flux value of a non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0050] The surface roughness of the steel sheet S can be obtained, for example, by measuring the surface roughness Ra (JIS B 0601-2001) of the steel sheet S using a roughness meter as the surface inspection device 8. The surface roughness of the steel sheet S surface varies depending on the conditions of the final annealing and coating when manufacturing the steel sheet S, and for example, the greater the surface roughness of the steel sheet S, the more unstable the processing state tends to be when subjected to magnetic domain refinement treatment. Therefore, the surface roughness of the steel sheet S affects the leakage magnetic flux value of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0051] The oxide thickness on the surface of the steel sheet S can be obtained by measuring the oxide thickness on the surface of the steel sheet S, for example, using an EPMA or AES as a surface inspection device 8. The oxide thickness on the surface of the steel sheet S varies depending on the conditions of the final annealing when manufacturing the steel sheet S, and for example, the thicker the oxide thickness on the surface of the steel sheet S, the more unstable the processing state tends to be when subjected to magnetic domain refinement treatment. Therefore, the oxide thickness on the surface of the steel sheet S affects the leakage magnetic flux value of non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0052] The amount of surface elements in the steel sheet S can be obtained by measuring the amount of surface elements on the surface of the steel sheet S, for example, using an EPMA or AES as a surface inspection device 8. Specifically, the concentration of Al and the like is measured as the amount of surface elements. The amount of surface elements in the steel sheet S varies depending on the conditions of the final annealing when manufacturing the steel sheet S, and for example, the higher the concentration (enriched) of Al in the surface region of the steel sheet S, the more unstable the processing state tends to be when subjected to magnetic domain refinement treatment. Therefore, the amount of surface elements in the steel sheet S affects the leakage magnetic flux value of a non-heat-resistant, magnetic domain refinement-oriented electrical steel sheet.

[0053] The thickness of the coating formed on the surface of the steel sheet S can be measured, for example, using a film thickness meter as a surface inspection device 8. The thickness of the coating varies depending on the coating conditions when manufacturing the steel sheet S, and for example, the thicker the coating, the more unstable the processing state tends to be when subjected to magnetic domain refinement processing. Therefore, the surface roughness of the steel sheet S affects the leakage magnetic flux value of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0054] (Environmental condition parameters when performing magnetic domain refinement treatment) Environmental condition parameters (also simply referred to as environmental condition parameters in this specification) relating to the environmental conditions when the magnetic domain refinement treatment is performed can be acquired by an environmental measurement device 6 or the like installed in the vacuum chamber 1. The environmental conditions when the magnetic domain refinement treatment is performed affect the processing state of the magnetic domain refinement treatment when the magnetic domain refinement treatment is performed on the steel sheet S. In other words, they affect the leakage magnetic flux value of the grain-oriented electrical steel sheet (non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet) after the magnetic domain refinement treatment has been performed.

[0055] Examples of environmental condition parameters for carrying out the magnetic domain refining process include temperature, humidity, degree of vacuum, pass line, tension, etc. At least one of these can be used as the environmental condition parameter for carrying out the magnetic domain refining process.

[0056] The temperature refers to the temperature of the environment in which the magnetic domain refinement treatment is performed. The humidity refers to the humidity of the environment in which the magnetic domain refinement treatment is performed. The temperature and humidity of the environment in which the magnetic domain refinement treatment is performed can be obtained by measuring the temperature and humidity of the environment in which the magnetic domain refinement treatment is performed, for example, using a thermo-hygrometer as the environmental measurement device 6. For example, when the magnetic domain refinement treatment is performed using the manufacturing equipment 10 shown in FIG. 1, the temperature and humidity refer to the temperature and humidity within the vacuum chamber 1, and can be measured using a thermo-hygrometer installed in the vacuum chamber 1. The temperature and humidity within the vacuum chamber 1 vary depending on the amount of gas and moisture brought into the vacuum chamber 1 by the steel sheet S. For example, if the temperature of the environment in which the magnetic domain refinement treatment is performed becomes high, the processed state tends to become unstable when the magnetic domain refinement treatment is performed on the steel sheet S. If the humidity of the environment in which the magnetic domain refinement treatment is performed becomes high, the processed state tends to become unstable when the magnetic domain refinement treatment is performed on the steel sheet S. Therefore, the temperature and humidity of the environment when the magnetic domain refinement treatment is carried out each affect the leakage magnetic flux value of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0057] The degree of vacuum is the degree of vacuum in the environment in which the magnetic domain refinement treatment is performed. The degree of vacuum in the environment in which the magnetic domain refinement treatment is performed can be obtained, for example, by measuring the degree of vacuum in the environment in which the magnetic domain refinement treatment is performed using a vacuum measuring device 6. For example, when the magnetic domain refinement treatment is performed using the manufacturing equipment 10 shown in FIG. 1 , the degree of vacuum is the degree of vacuum in the vacuum chamber 1, and can be measured using a vacuum gauge installed in the vacuum chamber 1. The degree of vacuum in the vacuum chamber 1 varies depending on the amount of gas and moisture brought into the vacuum chamber 1 by the steel sheet S. For example, if the degree of vacuum in the environment in which the magnetic domain refinement treatment is performed becomes low (if the pressure becomes high), the processing state tends to become unstable when the magnetic domain refinement treatment is performed on the steel sheet S. Therefore, the degree of vacuum in the environment in which the magnetic domain refinement treatment is performed affects the leakage magnetic flux value of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0058] The pass line is the height of the pass line (threading line) of the steel sheet S when the magnetic domain refinement treatment is performed. The pass line can be adjusted, for example, by adjusting the installation height of the rolls that transport the steel sheet S. The pass line changes the distance between the steel sheet S and the energy beam irradiation device 3 when the magnetic domain refinement treatment is performed. For example, if the pass line is lowered, the distance between the steel sheet S and the energy beam irradiation device 3 increases, and the energy beam is attenuated before it reaches the surface of the steel sheet S, which tends to make the processing state unstable when the steel sheet S is subjected to the magnetic domain refinement treatment. Therefore, the pass line when the magnetic domain refinement treatment is performed affects the leakage magnetic flux value of non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0059] The tension is the tension applied to the steel sheet S when the magnetic domain refinement treatment is performed. For example, when the magnetic domain refinement treatment is performed using the manufacturing equipment 10 shown in FIG. 1, the tension can be measured using a tensiometer attached to the tension reel 5. The tension can be adjusted by adjusting the peripheral speed of the rolls that transport the steel sheet S. For example, if the tension applied when the magnetic domain refinement treatment is performed is low, the processed state tends to become unstable when the magnetic domain refinement treatment is performed on the steel sheet S. Therefore, the tension applied when the magnetic domain refinement treatment is performed affects the leakage magnetic flux value of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0060] (Energy beam control parameters) Examples of control parameters (also simply referred to as control parameters in this specification) relating to the control conditions of the energy beam when performing the magnetic domain refinement treatment include the beam energy, focus, aperture, beam shape, and convergent current of the energy beam that performs the magnetic domain refinement treatment on the steel sheet S. At least one of these can be used as the control parameter.

[0061] The beam energy is the beam energy (W / cm) of the energy beam used in the magnetic domain refinement process. 2) The beam energy can be adjusted, for example, by changing the acceleration / deceleration voltage applied to the energy beam irradiation device. The beam energy affects the processing state, such as the depth of streaks, when magnetic domain refinement is performed. Therefore, the beam energy used when performing magnetic domain refinement treatment affects the leakage magnetic flux value of non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0062] The focus is the focus position relative to the beam irradiation surface of the steel sheet S when the magnetic domain refinement process is performed. The focus can be adjusted, for example, by adjusting the focusing coil and polarization system provided in the energy beam irradiation device. The focus affects the processing state, such as the depth and spacing of the streaks, when the magnetic domain refinement process is performed. Therefore, the focus affects the leakage magnetic flux value of non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0063] The aperture is the aperture size of the energy beam irradiated onto the steel sheet S when the magnetic domain refinement process is performed. The aperture size can be adjusted, for example, by adjusting the aperture size (aperture lens) of the energy beam irradiation device. The aperture size affects the processing state, such as the depth and spacing of the streaks, when the magnetic domain refinement process is performed. Therefore, the aperture size affects the leakage magnetic flux value of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0064] The beam shape refers to the shape of the X-axis cross section and the Y-axis cross section of the beam irradiated surface of the steel sheet S when the magnetic domain refinement treatment is performed. The beam shape can be adjusted, for example, by adjusting the polarization system provided in the energy beam irradiation device. The beam shape affects the processing state, such as the shape and spacing of the streaks, when the magnetic domain refinement treatment is performed. Therefore, the beam shape affects the leakage magnetic flux value of non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0065] The convergence current is the current value (convergence coil current value) supplied to the convergence coil when performing the magnetic domain refinement process. By adjusting the convergence current, it is possible to adjust the beam diameter on the beam irradiated surface of the steel sheet S. The convergence current affects the processing state, such as the width and depth of the streaks, when the magnetic domain refinement process is performed. Therefore, the convergence current affects the leakage magnetic flux value of non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0066] (Leakage magnetic flux value) The leakage flux value of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet can be measured downstream of the vacuum chamber 1 using a leakage flux value measuring device 9. The device described in Patent Document 1, for example, can be used as the leakage flux value measuring device 9. As described above, when the surface of the steel sheet S is subjected to magnetic domain refinement treatment by irradiating the surface with an energy beam in a streak-like manner, a streak-like processed portion (magnetic domain refinement processed portion) is generated on the surface of the steel sheet S due to the energy beam irradiation. Since the magnetic domain refinement processed portion contains magnetic flux leaking from the magnetic domain refinement processed portion (leakage magnetic flux), measuring the leakage flux can evaluate the processed state (workability) of the magnetic domain refinement treatment in the magnetic domain refinement grain-oriented electrical steel sheet. For example, if the amount of leakage flux is small, it can be determined that the processing in the magnetic domain refinement treatment (the processing that forms the streak-like processed portion) is unstable or insufficient. Note that if the processing in the magnetic domain refinement treatment is unstable or insufficient, the streak-like processed portion will not be clearly detected.

[0067] Therefore, by measuring the leakage magnetic flux, the processing state of the magnetic domain refinement process in a magnetic domain refinement grain-oriented electrical steel sheet can be evaluated. Specifically, as described in Patent Document 1, a leakage magnetic flux measurement device 9 performs fast Fourier transform (FFT) processing on the detected output signal from the magnetic domain refinement processed portion to obtain a frequency distribution. Then, in the frequency distribution, the processing state of the magnetic domain refinement process is evaluated using the intensity level of a predetermined frequency corresponding to the spacing between the stripes of the magnetic domain refinement processed portion. For example, if the magnetic domain refinement process is performed at 8 mm intervals, the intensity level at a wavelength of 8 mm is evaluated. In this case, in areas where the magnetic domain refinement process is unstable or insufficient, the intensity level at a wavelength of 8 mm is low, and in areas where the magnetic domain refinement process is sufficient, the intensity level at a wavelength of 8 mm is high. Therefore, the intensity level can be used as an indicator of the processing state (processability) of the magnetic domain refinement process.

[0068] In this embodiment, the actual data (measured values) including at least one surface condition parameter related to the surface condition of the steel sheet S when a magnetic domain refinement grain-oriented electrical steel sheet was previously manufactured using the manufacturing equipment 10, the actual data (measured values) including at least one environmental condition parameter related to the environmental conditions, the actual data (set values) including at least one control parameter related to the control conditions of the energy beam, and the actual data (measured values) of the leakage magnetic flux value are collected and stored by a host computer that oversees the manufacture of the non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

[0069] The leakage magnetic flux value prediction model generating device 100 acquires from a host computer a data set comprising a set of performance data including at least one surface condition parameter related to the surface condition of the steel sheet S, performance data including at least one environmental condition parameter related to the environmental conditions, performance data including at least one control parameter related to the control conditions of the energy beam, and performance data of the leakage magnetic flux value, and stores the data in a database 101.

[0070] At this time, the leakage magnetic flux value prediction model generating device 100 acquires the environmental condition parameters and the energy beam control parameters at the time when the region whose surface condition parameters have been measured by the surface inspection device 8 reaches the irradiation area of ​​the energy beam irradiation device 3. Furthermore, the leakage magnetic flux value prediction model generating device 100 acquires the leakage magnetic flux value of the region after magnetic domain refining processing has been performed on the region.

[0071] Specifically, the leakage magnetic flux value prediction model generating device 100 acquires a data set consisting of at least one actual data item of the surface condition parameters of the steel sheet S in an area that is the same distance from the leading end of the steel sheet S, at least one actual data item of the environmental condition parameters when performing the magnetic domain refinement process, at least one actual data item of the control parameters of the energy beam, and actual data item of the leakage magnetic flux value, and stores the data in the database 101.

[0072] Preferably, 100 or more data sets are stored in the database 101, and more preferably, 2000 or more data sets are stored in the database 101. Furthermore, it is desirable that the data sets include performance data for at least 100 coils.

[0073] Furthermore, the leakage flux value prediction model generating device 100 preferably acquires the above-mentioned data sets from at least the leading edge (e.g., within 20 m from the leading edge), the steady state portion, and the tail edge (e.g., within 20 m from the tail edge) of the steel sheet S. Furthermore, the leakage flux value prediction model generating device 100 preferably acquires data sets spanning the entire length of the steel sheet S at a predetermined interval (pitch) from the leading edge to the tail edge of the steel sheet S. The pitch for acquiring the data sets is preferably 50 m or more and 400 m or less. Creating a leakage flux value prediction model using data sets spanning the entire length of the steel sheet S enables more stable non-heat-resistant magnetic domain refinement processing. Furthermore, the leakage flux value prediction model generating device 100 may set a certain upper limit on the number of data sets and appropriately update the data sets stored in the database 101 within this upper limit.

[0074] The machine learning unit 102 uses the data set stored in the database 101 to generate a leakage magnetic flux value prediction model M that includes, as input data, one or more of the surface condition parameters of the grain-oriented electrical steel sheet before the magnetic domain refinement process is performed, one or more of the environmental condition parameters when the magnetic domain refinement process is performed, and one or more of the control parameters of the energy beam when the magnetic domain refinement process is performed, and that outputs data that is the leakage magnetic flux value of the grain-oriented electrical steel sheet after the magnetic domain refinement process is performed.

[0075] Specifically, the leakage magnetic flux value prediction model generating device 100 trains a machine learning model using a data set stored in the database 101 as training data, and generates a leakage magnetic flux value prediction model M trained by machine learning. The machine learning model used to generate the leakage magnetic flux value prediction model M may be any machine learning model as long as it provides prediction accuracy sufficient for practical use. For example, commonly used neural networks (including deep learning and convolutional neural networks), decision tree learning, random forests, support vector regression, etc. may be used. An ensemble model combining multiple models may also be used. A classification model such as a k-nearest neighbor method or logistic regression may also be used.

[0076] [Configuration of leakage magnetic flux value prediction device] Next, with reference to FIG. 3, an example of the configuration of a leakage flux value prediction device that predicts a leakage flux value using the leakage flux value prediction model of this embodiment will be described.

[0077] Fig. 3 is a block diagram showing an example of the configuration of a leakage flux value prediction device that predicts a leakage flux value using the leakage flux value prediction model of this embodiment. The leakage flux value prediction device 110 shown in Fig. 3 is configured by an information processing device such as a personal computer. The leakage flux value prediction device 110 stores the leakage flux value prediction model M generated by the leakage flux value prediction model generation device.

[0078] Before the region of the steel sheet S to be subjected to the magnetic domain refinement treatment reaches the irradiation area of ​​the energy beam irradiation device 3, the leakage flux value prediction device 110 inputs one or more surface condition parameters of the steel sheet S, one or more environmental condition parameters for performing the magnetic domain refinement treatment, and one or more control parameters of the energy beam for performing the magnetic domain refinement treatment into the leakage flux value prediction model M, thereby predicting the leakage flux value of the steel sheet S (magnetic domain refined grain-oriented electrical steel sheet) after the magnetic domain refinement treatment has been performed (leakage flux value prediction step). The leakage flux value prediction device 110 then outputs information related to the prediction result to the magnetic domain refinement treatment condition setting device 120. Note that in this embodiment, the magnetic domain refinement treatment condition setting device 120 is configured by an information processing device such as a personal computer and is configured separately from the leakage flux value prediction device 110, but is not limited to this. For example, the leakage magnetic flux value prediction device 110 may be configured to implement the flow of the magnetic domain refining processing condition setting device 120.

[0079] The magnetic domain refinement processing condition setting device 120 compares the target range of leakage flux values ​​obtained from the host computer 130 with the predicted result output from the leakage flux value predicting device 110 to determine whether the leakage flux value of the magnetic domain refined grain-oriented electrical steel sheet is good or bad. If the predicted result of the leakage flux value is determined to be good (within the target range), the magnetic domain refinement processing condition setting device 120 continues operation of the manufacturing equipment 10. On the other hand, if the predicted result of the leakage flux value is determined to be bad (outside the target range), the magnetic domain refinement processing condition resetting unit 121 of the magnetic domain refinement processing condition setting device 120 resets the operating conditions of the manufacturing equipment 10. The reset operating conditions are preferably one or more of the control parameters of the energy beam when performing the magnetic domain refinement processing (resetting step). As a result, it is possible to reduce the frequency of leakage flux values ​​falling outside the target range and manufacture non-heat-resistant magnetic domain refined grain-oriented electrical steel sheets with improved manufacturing yield.

[0080] Conventionally, there has been no method for predicting the leakage flux value of a grain-oriented electrical steel sheet after magnetic domain refinement treatment before the grain-oriented electrical steel sheet is subjected to the magnetic domain refinement treatment. In the present invention, a leakage flux value prediction model is used, in which input data includes one or more surface condition parameters related to the surface condition of the grain-oriented electrical steel sheet before the magnetic domain refinement treatment, one or more environmental condition parameters related to the environmental conditions during the magnetic domain refinement treatment, and one or more control parameters related to the energy beam control conditions during the magnetic domain refinement treatment, and the leakage flux value of the grain-oriented electrical steel sheet after the magnetic domain refinement treatment (non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet) is used as output data. This makes it possible to predict the leakage flux value of a non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet before the magnetic domain refinement treatment is performed. Therefore, the conditions of the manufacturing equipment can be optimized at an earlier stage so that the leakage flux value of the non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet is appropriate. This allows the non-heat-resistant magnetic domain refinement treatment to be performed more stably. As a result, the product yield of the non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet is further improved.

[0081] Furthermore, the leakage flux value prediction model M of this embodiment uses surface condition parameters of the steel sheet (steel sheet S) as input data. This makes it possible to generate a leakage flux value prediction model M that reflects the surface condition of the steel sheet S. Furthermore, the leakage flux value prediction model M of this embodiment uses environmental condition parameters related to the environmental conditions when the magnetic domain refining process is performed as input data. This makes it possible to generate a leakage flux value prediction model M that reflects the environmental conditions when the magnetic domain refining process is performed. Furthermore, the leakage flux value prediction model M of this embodiment uses control parameters of the energy beam when the magnetic domain refining process is performed as input data. This makes it possible to generate a leakage flux value prediction model M that reflects the control conditions of the energy beam when the magnetic domain refining process is performed. The surface condition parameters of the steel sheet (steel sheet S), the environmental condition parameters when performing the magnetic domain refinement process, and the control parameters of the energy beam affect the leakage magnetic flux value. Therefore, by combining these parameters and using them as input data, it is possible to accurately predict the leakage magnetic flux value of non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet. [Example]

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0083] In this embodiment, an example will be described in which the non-heat-resistant magnetic domain refining method of the present invention is applied to a manufacturing facility 10 shown in FIG.

[0084] The steel sheet S used was a grain-oriented electrical steel sheet that had undergone final annealing. Using 200 coils of the grain-oriented electrical steel sheet, the grain-oriented electrical steel sheet was subjected to a non-heat-resistant magnetic domain refinement treatment in the manufacturing equipment 10 shown in FIG. 1 to produce a non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet. When producing the non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet, the surface condition parameters of the steel sheet S were obtained using a surface inspection device 8. Furthermore, the environmental condition parameters and energy beam control parameters used during the magnetic domain refinement treatment were varied in the longitudinal direction of the steel sheet S, and the environmental condition parameters were obtained using an environment measurement device 6. Then, leakage flux measurement device 9 was used to obtain actual data on the leakage flux values ​​of the non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet, corresponding to the surface condition parameters of the steel sheet S, the environmental condition parameters used during the magnetic domain refinement treatment, and the energy beam control parameters set during the magnetic domain refinement treatment. These data were collected and stored by a host computer that oversees the production of the non-heat-resistant magnetic domain refined grain-oriented electrical steel sheet.

[0085] The leakage flux value prediction model generating device 100 acquired, from a host computer, actual data on the surface state parameters of the steel sheet S, actual data on the environmental condition parameters when the magnetic domain refinement treatment was performed, and actual data on the control parameters of the energy beam set when the magnetic domain refinement treatment was performed, and stored these in a database 101. At this time, the leakage flux value prediction model generating device 100 also acquired actual data on the leakage flux values ​​from the host computer, and stored this in the database 101 in association with the actual data on the surface state parameters, the actual data on the environmental condition parameters, and the actual data on the control parameters of the energy beam.

[0086] As described above, when 2000 data sets were accumulated in the database 101, 1600 pieces of training data were extracted from the database 101. The extracted training data was used by the machine learning unit 102 to generate a leakage magnetic flux value prediction model M. In this example, the machine learning unit 102 used the following input data for the leakage magnetic flux value prediction model M: the coating thickness of the steel sheet S as actual data on the surface condition parameters of the steel sheet S; the vacuum degree of the vacuum chamber 1 as actual data on the environmental condition parameters when performing the magnetic domain refinement treatment; and the convergence current as a control parameter for the energy beam when performing the magnetic domain refinement treatment. A neural network was used as the machine learning method, with three hidden layers and five nodes in each hidden layer. A sigmoid function was used as the activation function.

[0087] The leakage flux value prediction device 110, which stores the leakage flux value prediction model M generated as described above, was used to output the predicted leakage flux value for each control cycle of the manufacturing equipment 10, with a 200-m pitch in the longitudinal direction of the steel sheet S. The magnetic domain refinement processing condition setting device 120 compared the predicted result with the target range obtained from the host computer and adjusted (reset) the convergence current of the energy beam so that the leakage flux value fell within the target range, thereby producing a non-heat-resistant, domain-refined grain-oriented electrical steel sheet. Specifically, the convergence current of the energy beam was adjusted so that the predicted leakage flux value was the median value of the target range. In this example, the target range of the leakage flux value was set by the intensity level of the frequency corresponding to the interval of the magnetic domain refinement processing in the frequency distribution obtained by fast Fourier transform of the output signal from the magnetic domain refinement processing section detected by the leakage flux value measurement device 9. The results are shown in Figure 4. The leakage magnetic flux values ​​shown in FIG. 4 are data actually measured at intervals of 200 m along the coil length (longitudinal direction of the steel plate S).

[0088] The leakage flux value fell outside the lower limit of the target range approximately 1000 m from the tip of steel plate S, but when the energy beam control parameter was reset to the convergence current presented by leakage flux value prediction model M and operation was resumed, the leakage flux value was able to quickly return to within the target range.

[0089] On the other hand, the comparative example is an example in which operation was performed based on past performance data. In other words, it is an example in which operation was performed without performing prediction using the leakage flux value prediction model M. As shown in FIG. 4, in the comparative example, there were cases in which the leakage flux value remained outside the target range during operation and could not be restored. That is, in the example, even if the leakage flux value deviated from the target range, it was possible to control it so that it was within the target range, whereas in the comparative example, although control was performed based on past performance data (empirical rules), the leakage flux value fluctuated near the lower limit of the target range and ultimately deviated from the target range. [Explanation of symbols]

[0090] 1 Vacuum chamber 3 Energy beam irradiation device 4 Payoff Reel 5 Tension Reel 6 Environmental measurement device 8. Surface inspection equipment 9. Leakage magnetic flux measuring device 10. Manufacturing equipment for non-heat-resistant magnetic domain refined grain-oriented electrical steel sheets 100 Leakage magnetic flux value prediction model generation device 101 Database 102 Machine Learning Department 110 Leakage magnetic flux value prediction device 120 Magnetic domain refinement processing condition setting device 121 Magnetic domain refinement processing condition resetting section M Leakage magnetic flux value prediction model S steel plate (oriented electrical steel plate)

Claims

1. A non-heat-resistant magnetic domain refining treatment method, comprising irradiating a grain-oriented electrical steel sheet with an energy beam to perform a non-heat-resistant magnetic domain refining treatment on the grain-oriented electrical steel sheet, a leakage flux value prediction step of predicting a leakage flux value of the grain-oriented electrical steel sheet after the magnetic domain refinement treatment using a leakage flux value prediction model learned by machine learning, the leakage flux value prediction model including, as input data, one or more surface condition parameters related to the surface condition of the grain-oriented electrical steel sheet before the magnetic domain refinement treatment, one or more environmental condition parameters related to the environmental conditions when the magnetic domain refinement treatment is performed, and one or more control parameters related to the control conditions of the energy beam when the magnetic domain refinement treatment is performed, and the leakage flux value of the grain-oriented electrical steel sheet after the magnetic domain refinement treatment is used as output data.

2. 2. The non-heat-resistant magnetic domain refining method according to claim 1, further comprising a step of resetting the control parameters when the leakage flux value predicted in the leakage flux value prediction step falls outside a target range so that the leakage flux value falls within the target range.

3. A method for producing a non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet, comprising: subjecting a grain-oriented electrical steel sheet to a non-heat-resistant magnetic domain refinement treatment using the non-heat-resistant magnetic domain refinement treatment method according to claim 1 or 2 to produce a non-heat-resistant magnetic domain refinement grain-oriented electrical steel sheet.

Images