1135 results about "Electrical steel" patented technology

The invention relates to the technical field of steel production and processing, and discloses an electrical steel strip annealing temperature real-time monitoring and regulation system. The system comprises a temperature data acquisition module which is responsible for acquiring temperature and cooling rate data in an annealing process and acquiring expected parameters; the temperature deviation analysis module is used for calculating a deviation coefficient through a dynamic weighting algorithm to construct a matrix; the dynamic regulation and control module is used for generating regulation and control parameters based on a fuzzy logic control algorithm; the abnormity grading module is used for grading annealing abnormity; and the real-time feedback module transmits the regulation and control parameters and the abnormal identifier to the control end. The system also has the functions of adjusting a rule base according to the characteristics of the steel strip, backtracking historical data, optimizing regulation and control, adaptively updating an abnormal threshold value and the like. Through cooperative work of all the modules, real-time monitoring and accurate regulation and control of the annealing temperature are achieved, the annealing quality and production efficiency of the electrical steel strip are improved, and the cost is reduced.

The invention belongs to the technical field of non-oriented electrical steel manufacturing, and relates to a method for producing non-oriented silicon steel based on thin-strip cast rolling. The low-silicon and aluminum-free component design is adopted, the hot-rolled thin substrate is directly obtained through thin strip cast rolling, casting blank continuous casting and casting blank heating are omitted, the hot rolling reduction is greatly reduced, it is avoided that unfavorable textures of alpha and gamma components in the finished non-oriented silicon steel are remarkably improved, and the high magnetic induction of the finished product is guaranteed; after acid pickling and cold rolling, grain growth is promoted by means of high-temperature cover annealing, and low iron loss of a finished product is guaranteed; the high-magnetic-induction low-iron-loss non-oriented silicon steel with the thickness specification of 0.50 mm is obtained, the grain size of a finished product is 80-100 microns, the iron loss P1.5 / 50 is smaller than or equal to 4.0 W / kg, and the magnetic induction B5000 is larger than or equal to 1.76 T.

A double cold rolled non-oriented electrical steel sheet having a composition including: 0.0001%≤Carbon≤0.007%, 0.1%≤Manganese≤0.2%, 3.1%≤Silicon≤3.6%, 0.8%≤Aluminum≤1.1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition being iron and unavoidable impurities caused by processing, the microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, is from 35% to 45% when calculated in accordance of Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.64 T to 1.66 T.

A double cold rolled non-oriented electrical steel sheet having a composition including, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.3%, 3.2%≤Silicon≤3.8%, 0.8%≤Aluminum≤1.1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition being iron and unavoidable impurities caused by processing, the microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 30% when calculated in accordance of Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.66 T to 1.69 T.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%,, 0.15% ≤Manganese≤0.2%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn ≤5.5%, and can contain various optional elements, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, of 35 to 55% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.635T to 1.670T.

A double cold rolled non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.1%≤Manganese≤0.3%, 3.1%≤Silicon≤3.8%, 0.6%≤Aluminum≤0.8%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition is iron and unavoidable impurities caused by processing. The microstructure ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, of 40 to 50% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.66T to 1.7T.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.25%, 3.2%≤Silicon≤3.8%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and various optional elements. The remainder composition is iron and unavoidable impurities caused by processing. The microstructure is ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 33% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.630T to 1.65T.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.21%≤Manganese≤0.7%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and can contain various optional elements. The remainder composition being composed of iron and unavoidable impurities. The microstructure is ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 35% to 45% and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.63T to 1.66T.

The invention relates to the technical field of steel production, and discloses an electrical steel strip rolling process intelligent scheduling and energy consumption prediction system, which comprises a data acquisition module, a dynamic scheduling module, an energy consumption prediction module, an anomaly detection module and an optimization feedback module. The data acquisition module acquires data by using a distributed sensor network; the dynamic scheduling module optimizes scheduling based on an improved genetic algorithm; the energy consumption prediction module adopts a deep space-time convolutional neural network to predict energy consumption; the anomaly detection module detects anomaly based on an isolated forest algorithm; and the optimization feedback module adjusts a scheduling strategy through a reinforcement learning framework. The system realizes intelligent scheduling of the rolling process and accurate prediction of energy consumption, can effectively improve production efficiency, reduce energy consumption, timely discover abnormity and optimize a scheduling scheme, and has remarkable economic benefits and production management advantages.

Provided is an electrical steel strip friction stir welding method that is able to inhibit the occurrence of coil joint fractures on a production line caused by deterioration of mechanical properties and shape of the coil joint while maintaining high work efficiency and that is also advantageous in terms of rotating tool durability. In the method, preheated double-sided friction stir welding is performed, diameter D (mm) of shoulders of rotating tools satisfies the relationship of the following Expression (7), and rotation speed RS (r / min) of the rotating tools, the diameter D (mm) of shoulders of the rotating tools, and joining speed JS (mm / min), expressed as RS×D3 / JS, satisfy the relationship of the following Expression (8), 4×TJ≤D≤10×TJ . . . (7), and 180×TJ≤RS×D3 / JS≤1500×TJ . . . (8).

The invention discloses a near-net-shape endless rolling non-oriented electrical steel ultra-thin strip and a preparation method thereof, and belongs to the technical field of metal processing. According to the method, the near-net-shape endless rolling non-oriented electrical steel ultra-thin strip with the finished product thickness being only 0.05-0.15 mm is prepared through the processes of smelting, thin slab continuous casting, endless rolling hot continuous rolling, coiling, online heat preservation, acid pickling, primary cold rolling and continuous annealing, normalizing and secondary cold rolling annealing are not needed in the process, and short-process, low-cost and efficient production can be achieved. The defects that the surface of the non-oriented electrical steel ultra-thin strip is corrugated, the magnetic performance is poor, the surface is scratched and severely narrowed in the annealing process, iron loss is not easy to control, and energy consumption is high are overcome, and the prepared non-oriented electrical steel ultra-thin strip is excellent in magnetic property and can be applied to high-frequency and high-speed motors. And the development requirements of new energy and low-altitude economy are met.

The invention relates to a normalizing-free method for producing non-oriented electrical steel. The method comprises the following steps: 1) performing multi-pass finish rolling, cooling and coiling on an intermediate billet to obtain a hot-rolled coil plate with the thickness of 2.30-2.60 mm; (2) the hot-rolled coil plate is not subjected to normalizing treatment, but is sequentially subjected to uncoiling, acid pickling, rinsing, drying, cold rolling and coiling, and a cold hard coil with the thickness being 0.35-0.65 mm is obtained; (3) the cold hard coil is subjected to finished product annealing in the mixed atmosphere of H2 and N2 through a continuous annealing furnace, the finished product annealing temperature ranges from 850 DEG C to 1000 DEG C, and the annealing time ranges from 50 s to 70 s; and cooling, coating and finishing the annealed steel strip to obtain a non-oriented electrical steel finished product. The method has the advantages that under the condition that normalizing intermediate annealing is not adopted, the burden of production procedures such as steelmaking and hot rolling can be relieved, the control difficulty of harmful elements and inclusions in the steelmaking link is lowered, and the control difficulty of recrystallization microscopic structures in the hot rolling link is lowered.

The invention discloses a complex magnetic field excitation-oriented electrical steel dynamic magnetic field intensity calculation method, which comprises the following steps of: firstly, performing infinite interpolation expansion on the basis of a small number of actually measured symmetric hysteresis loops to reduce the experimental data volume required by static Preisach hysteresis model identification; an improved dynamic modeling method is provided, model parameters related to the magnetization rotation point and the magnetic bias quantity are introduced, and the method has higher adaptability compared with a traditional model under complex excitation. An improved particle swarm optimization algorithm is adopted to optimize parameters in the dynamic Preisach hysteresis model, a population eradication and loop initialization mechanism is introduced into the improved particle swarm optimization algorithm, the optimization precision is obviously improved compared with that of a classical particle swarm algorithm, and more efficient model parameter identification and more accurate dynamic hysteresis loop simulation are achieved; based on electrical steel hysteresis loop test data under various excitation conditions, it is more comprehensively verified that the provided modeling method and parameter optimization algorithm have better comprehensive performance.

The invention discloses a manufacturing method for improving the cold-rolled edge crack defect of high-silicon phase-change-free electrical steel, which comprises the following steps: converting molten iron by a converter, transferring to an RH (Ruhrstahl Heraeus) furnace, carrying out vacuum smelting, carrying out alloying treatment, and continuously casting the molten steel with chemical components meeting requirements into a plate blank; the plate blank is hot-rolled into a hot-rolled plate after being heated and subjected to heat preservation; and the hot-rolled plate is subjected to normalizing, acid pickling, cold rolling, continuous annealing and insulating coating coating to prepare a high-silicon phase-change-free electrical steel finished product. In the hot rolling process, the steel plate is transversely rolled through a vertical roller, the vertical roller reduction rate delta B of the vertical roller pass meets the condition that delta B is larger than or equal to 10 * delta h / H inlet and smaller than or equal to 18 * delta h / H inlet, delta h is the thickness difference of the plate blank before and after the pass, and H inlet is the thickness of the plate blank at the pass inlet. Through the process design of the procedures of continuous casting, heating, hot rolling, normalizing, cold rolling and the like, the structure uniformity of the material is improved, especially the structure uniformity in the thickness direction, and the one-time passing rate of cold rolling is 95% or above.

The invention belongs to the technical field of cold-rolled oriented electrical steel strip manufacturing, and particularly relates to a low-noise cold-rolled oriented electrical steel strip for a transformer, a preparation method of the low-noise cold-rolled oriented electrical steel strip and the transformer. The method comprises the following steps: heating a sheet billet to obtain a heated sheet billet, carrying out hot continuous rolling on the heated sheet billet to obtain a hot-rolled sheet, and sequentially carrying out normalizing pickling, primary cold rolling, decarburization annealing, secondary cold rolling, MgO separant coating, cover type high-temperature annealing, stretching leveling and insulating coating on the hot-rolled sheet to prepare a finished oriented electrical steel strip with the thickness of 0.15-0.20 mm, the slab comprises the following chemical elements in percentage by mass: 0.02% < = C < = 0.08%, 2.50% < = Si < = 3.20%, 0.10% < = Mn < = 0.50%, 0.02% < = P, 0.05% < = Als < = 0.15%, 0.10% < = Cu < = 0.50%, 0.05% < = Sb < = 0.15%, 0.005% < = S < = 0.015%, 0.005% < = N < = 0.015%, 0.004% < = Ti and the balance of Fe and inevitable impurities. The iron loss P1.7 / 50 of the cold-rolled oriented electrical steel strip finished product prepared by the method is less than or equal to 1.00 W / kg, the iron loss B8 is greater than or equal to 1.94 T, and the test noise of a transformer manufactured by the steel strip at a position of 3m is less than 15dB.

The invention deals with a non-oriented electrical steel sheet having a composition of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.05%≤Manganese≤0.15%, 2.5%≤Silicon≤3.1%, 0.26%≤ Aluminum≤0.7%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition is composed of iron and unavoidable impurities caused by processing. The microstructure of the steel sheet is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 35% to 45% when calculated in accordance of Bertotti method.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001% ≤ Carbon≤0.007%, 0.17%≤Manganese≤0.4%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5% and can contain various optional elements the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 25% when calculated in accordance of Bertotti method.

A non-oriented electrical steel sheet having a composition of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.09%≤Manganese≤0.15%, 2.5%≤Silicon≤3%, 0.1% ≤ Aluminum≤0.5%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 35% to 45% when calculated in accordance of Bertotti method.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.18%≤Manganese≤0.5%, 3.1%≤Silicon≤3.8%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and can contain various optional elements the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 34% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.60 T to 1.65 T.

A non-oriented electrical steel sheet having a composition including the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.7%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and can contain various optional elements, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 30 to 40% when calculated in accordance with Bertotti method.

Provided are a grain-oriented electrical steel sheet and stacked iron core having properties that can achieve both low iron loss and low noise in transformers by suppressing vibration caused by electromagnetic forces at the joint parts of the stacked iron core. The grain-oriented electrical steel sheet comprises, on at least one of both surfaces thereof, a plurality of strain regions that extend linearly in a direction transverse to a rolling direction of the steel sheet and are arranged at intervals in the rolling direction, wherein a standard deviation σBr of residual magnetic flux density Br determined from a hysteresis loop measured by exciting the steel sheet to 1.7 T with the rolling direction as a magnetization direction is 0.38 or less.

The present disclosure relates to the technical field of iron and steel, in particular to an electrical steel with low iron loss and method for controlling tension thereof during decarburization annealing. A tension of each procedure of decarburization annealing of the electrical steel is controlled and adjusted respectively, and further combined with temperature of the decarburization annealing furnace, treatment time of the electrical steel in decarburization annealing furnace, and width and thickness of the electrical steel to prevent deflecting, cracking and narrowing of the electrical steel in the furnace and nodules on the bottom of roller. Compared with products of same brand, surface roughness and magnetic hysteresis loss of product are decreased by 10-20% and 10-15%.

The invention belongs to the technical field of non-oriented electrical steel manufacturing, and relates to a method for producing high-magnetic-induction low-iron-loss non-oriented silicon steel based on thin-strip cast rolling. The low-silicon aluminum-free component design is adopted, the hot-rolled thin substrate with the thickness of 1.60 + / -0.10 mm is directly obtained through thin strip cast rolling, the rolling reduction of hot rolling and cold rolling is greatly reduced, the situation that due to hot rolling and cold rolling with the large compression ratio, alpha and gamma components in a non-oriented silicon steel texture are remarkably improved is avoided, and the magnetic induction of a finished product is improved. The non-oriented silicon steel with the thickness specification of 0.20-0.35 mm is obtained by combining with accurate control of the hot rolling-cold rolling-annealing process, the non-oriented silicon steel has low iron loss and high magnetic induction, the iron loss P1.5 / 50 is 3.3-4.5 W / kg, and the magnetic induction B5000 is 1.78-1.81 T. The double-roller thin-strip continuous casting method is adopted, compared with a conventional process, the processes of hot rolling heating, hot rolling rough rolling, normalizing and the like are omitted, and the double-roller thin-strip continuous casting method is an energy-saving and environment-friendly short-process production technology.

This grain-oriented electrical steel sheet includes a base steel sheet, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, in which, in the base steel sheet, a plurality of linear strain regions that extend continuously or intermittently in a direction intersecting with a rolling direction are present, the plurality of linear strain regions are each 210 μm or less in width in the rolling direction, the plurality of linear strain regions are parallel to each other, intervals of linear strain regions adjacent to each other in the rolling direction are 10 mm or less, and magnetostriction λ0-pb in a unit of μm / m when the grain-oriented electrical steel sheet is excited up to 1.7 T and magnetostriction λ0-pa in a unit of μm / m when the grain-oriented electrical steel sheet is heat-treated at 800° C. for 4 hours and then excited up to 1.7 T satisfy 0.02≤λ0-pb−λ0-pa≤0.20.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.2%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, various optional elements. The remainder composition is iron and unavoidable impurities caused by processing. The microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, of 35 to 55% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000A / m (J50) from 1.635T to 1.670T.

The invention discloses a normalizing-free method for producing high-grade non-oriented electrical steel, and belongs to the technical field of steel rolling. In order to solve the problem in non-normalizing production of high-grade non-oriented electrical steel with high silicon and high aluminum, the invention provides a method for producing the high-grade non-oriented electrical steel without normalizing, the high-grade non-oriented electrical steel contains 2.8-3.2 wt% of Si and 0.2-1 wt% of Al, and a hot rolling process, an acid pickling process and a cold rolling process are adopted, the hot rolling process adopts low-temperature plate blank heating, width fixing, rough rolling, finish rolling and high-temperature coiling heat treatment, and the cold rolling process adopts primary cold rolling, intermediate annealing, secondary cold rolling and finished product annealing. Under the condition of no special normalizing production line for the electrical steel, the hot rolling reduction rate and the coiling temperature are adjusted, the heat preservation pit is additionally arranged, hot rolling waste heat self-annealing is used for replacing normalizing, and the reduction rate and the annealing temperature of primary cold rolling and secondary cold rolling are reasonably distributed; and the high-efficiency non-oriented electrical steel with excellent large grain size and excellent magnetic performance is successfully developed.

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

A non-oriented electrical steel sheet having a composition including, expressed in percentage by weight: 0.0001%≤Carbon≤0.005%, 0.2%≤Manganese≤0.3%, 3.1%≤Silicon≤3.6%, 0.6%≤Aluminum≤1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition being iron and unavoidable impurities caused by processing, the microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 30% to 35% when calculated in accordance of Bertotti method.

A non-oriented electrical steel sheet according to an embodiment of the present invention comprises, in weight %: 1.5-4.5% of Si; 0.1-2.0% of Al; and 0.1-2.0% Mn, the remainder being Fe and inevitable impurities. The sheet comprises an oxide layer that is inward of the surface, wherein the length of a discontinuous part of the oxide layer, where the thickness of the oxide layer, in a cross section comprising the rolling direction of the steel sheet, is 2nm or less, is 5 to 500nm per 200µm in the rolling direction.

This grain-oriented electrical steel sheet includes a base steel sheet having a predetermined chemical composition, a glass coating formed on the base steel sheet, and a tension-applied insulation coating formed on the glass coating, on a front surface of the base steel sheet, a plurality of linear strains that extend continuously or intermittently in a direction intersecting with a rolling direction are present, intervals p in the rolling direction of the plurality of linear strains adjacent to each other are 3.0 to 9.0 mm, widths of the linear strains are 10 to 250 μm, and, in an X-ray topographic spectrum in a range of 1.50 mm in the rolling direction that is obtained from an X-ray topographic image of the front surface and includes the linear strain at a center, a full width at half maximum of a peak of the X-ray topographic spectrum including a maximum value of a spectral intensity is 0.02 mm or more and 0.10 mm or less.