778 results about "Electrical steel" patented technology

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 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 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.

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.

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.

The purpose of the present invention is to propose a method for flattening annealing a grain-oriented electromagnetic steel sheet and a method for producing a grain-oriented electromagnetic steel sheet in which slip between a grain-oriented electromagnetic steel sheet and hearth rolls is suppressed in flattening annealing. In this method for flattening annealing a grain-oriented electromagnetic steel sheet, one or more ceramic hearth rolls are arranged as hearth rolls for transporting the grain-oriented electromagnetic steel sheet in an annealing furnace, and when controlling an optimum forward slip rate in the ceramic hearth rolls, the optimum forward slip rate is determined by subtracting the hearth roll thermal elongation rate from the steel sheet thermal elongation rate or by subtracting the hearth roll thermal elongation rate from the steel sheet thermal elongation rate and adding a drive droop deceleration rate. The method for producing a grain-oriented electromagnetic steel sheet includes a flattening annealing step in which the optimum forward slip rate of the hearth rolls is controlled so that the slip rate between the hearth rolls and the grain-oriented electromagnetic steel sheet is equal to or less than a predetermined threshold value.

Provided is a non-oriented electrical steel sheet that is excellent in iron loss and magnetic anisotropy under high magnetic flux and high frequency conditions, and a method for manufacturing the same. [Solution] A method for producing a grain-oriented electrical steel sheet includes the steps of heating a slab containing, by weight, 1.5 to 6.5% Si, 0.0005 to 3.5% Al, 0.01 to 3.0% Mn, 0.005 to 5.0% Cr, 0.0005 to 0.03% S, the balance being Fe and other unavoidable impurities, at 1050 to 1220°C, finish hot rolling the slab to obtain a hot-rolled sheet, hot-rolling the hot-rolled sheet at 850 to 1150°C for 30 to 300 seconds, cold-rolling the hot-rolled sheet that has been annealed to obtain a cold-rolled sheet, heating the cold-rolled sheet, and rolling the heated cold-rolled sheet. and final annealing at 600 to 1150°C for 10 to 300 seconds, wherein the cold rolling satisfies the following [Relationship 2], wherein the heating rate in the temperature range of 300 to 500°C during heating is 5 to 150°C / s, and the gas atmosphere in the temperature range of 500 to 750°C during the final annealing is composed of, by volume, 15 to 99.99% hydrogen, 0.0001 to 0.0030% oxygen, and the balance being an inert gas, and the oxygen content in the gas atmosphere in the temperature range of 800 to 1100°C during the final annealing is 1 to 1.5 times that in the temperature range of 500 to 750°C. [Relationship 2] Maximum temperature of cold-rolled sheet surface during cold rolling < 200 × cold rolling reduction / 100 + 40

A non-oriented electrical steel sheet having a composition of the following elements, expressed in percentage by weight 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.25%, 2.9%≤Silicon≤3.4%, 0.8%≤Aluminum≤1.1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and the following optional elements 0%≤Niobium≤0.1%, 0%≤Titanium≤0.1%, 0%≤Vanadium≤0.1%, 0%≤Chromium≤1%, 0%≤Molybdenum≤0.5%, 0%≤Tungsten≤0.1%, 0%≤Cobalt≤1%, 0%≤Arsenic≤0.05%, 0.001%≤Calcium≤0.01%, 0%≤Copper≤1%, 0%≤Nickel≤1%, 0%≤Boron≤0.05%, 0%≤Lead≤0.2%, 0%≤Tin≤0.2%, 0%≤Antimony≤0.2%, the remainder composition being composed of iron and unavoidable impurities caused by processing. The microstructure is 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 less than 25% and simultaneously having a magnetic polarization at 5000 A / m from 1.625 T to 1.690 T.

This grain-oriented electrical steel sheet is a grain-oriented electrical steel sheet having a final annealing film mainly composed of forsterite and an insulation coating containing pseudo-tetragonal aluminum borate and silica on its surface, wherein one surface or both surfaces of the steel sheet have linear grooves or dot-row shaped recesses with a depth of 5 to 40 μm.

The present invention provides a manufacturing method for grain-oriented electrical steel sheet that improves magnetic properties by controlling the tension applied to the steel sheet during the insulating coating layer formation process, adjusting the stress applied to each layer, and suppressing the formation of subgrain boundaries. [Solution] The magnetic steel sheet includes an electrical steel sheet substrate containing 2.0 to 7.0% by weight of Si and 0.01 to 0.07% by weight of Sb, with the remainder being Fe and other unavoidable impurities, a fine-grained interface layer located from the surface of the electrical steel sheet substrate toward the inside of the electrical steel sheet substrate, a base coating layer located on the fine-grained interface layer, and an insulating coating layer located on the base coating layer, and satisfies the following formula 1. [Formula 1] ([P]×[PS]+[F]×[FS]+[C]×[CS]) / -([S] / 2)≧13.0MPa (In formula 1, [P] is the thickness of the insulating coating layer (μm), [PS] is the residual stress of the insulating coating layer (MPa), [F] is the thickness of the base coating layer (μm), [FS] is the residual stress of the base coating layer (MPa), [C] is the thickness of the fine grain interface layer (μm), [CS] is the residual stress of the fine grain interface layer (MPa), and [S] is the thickness of the electrical steel sheet substrate (μm).)

The invention discloses a non-oriented electrical steel plate with excellent blanking processing performance, which contains Fe and inevitable impurities, and also contains the following chemical elements in percentage by mass: 0 < C < = 0.004%, 0.8-2.2% of Si, 0.05-0.5% of Mn, 0.005-0.15% of P, 0 < Al < = 0.1%, 0.0003-0.01% of Ca + Ce, and the balance of Fe and inevitable impurities. Wherein the value of Si / 10 is 0.53%-22%. The invention also discloses a manufacturing method of the non-oriented electrical steel plate. The manufacturing method comprises the following steps: smelting and casting; heating and hot rolling; performing cold rolling after pickling; and continuous annealing: the soaking time is controlled to be 5-60 s, and the soaking temperature T is equal to 850 + 11a * {[Si] / (10 * [P])}. According to the non-oriented electrical steel plate and the manufacturing method thereof, the non-oriented electrical steel plate has a proper iron loss coefficient and excellent electromagnetic performance, and meanwhile, the non-oriented electrical steel plate also has good blanking processing performance.

Provided are a hot-rolled non-oriented electrical steel sheet and a manufacturing method thereof, in which shot balls are projected onto the steel sheet in the manufacturing process to remove scale, and the surface and internal hardness is adjusted after the shot ball projection, thereby improving iron loss in all directions and iron loss after stress relief annealing. The hot-rolled non-oriented electrical steel sheet of the present invention contains, by weight %, 2.8 to 4.0% Si, 0.1 to 1.3% Al, 0.3 to 2.0% Mn, and the balance being Fe and unavoidable impurities, and satisfies the following formula 1: [Formula 1] 1.1≦Hv1 / HV2≦1.5 (In Equation 1, HV1 represents the hardness measured on the surface of the steel plate, and HV2 represents the hardness measured at a point halfway through the thickness of the steel plate.) It is characterized by further containing one or more of Cr: 0.2 wt % or less (excluding 0%), Sn: 0.06 wt % or less (excluding 0%), and Sb: 0.06 wt % or less (excluding 0%).

The present invention can provide a non-oriented electrical steel sheet having improved surface properties and magnetic properties, and another aspect provides a method for manufacturing the non-oriented electrical steel sheet.

This electromagnetic steel sheet with an adhesive film is provided with: an electromagnetic steel sheet; and an adhesive film provided on at least a portion of one or both surfaces of the electromagnetic steel sheet, the adhesive film containing a crosslinkable thermoplastic resin (A) and a thermoplastic resin (B) other than the crosslinkable thermoplastic resin (A), the adhesive film having a hardness of 200-260 MPa, and the adhesive film having a hardness of 200-260 MPa. The adhesive film has a hardness of 200 to 300 MPa after the adhesive film is heated at 200 DEG C for 5 minutes.

This grain-oriented electrical steel sheet is provided with a base steel sheet and an insulating coating film, wherein the insulating coating film contains, in terms of mass%, 10%-20% of P, 18%-25% of Si, 1.1%-2.7% of V, and 2%-5% of Al as a chemical composition, and Cr is limited to less than 0.1%.

A method for packaging sheet metal parts made from an electrical steel strip or sheet to form a laminated core is disclosed. In order to achieve advantageous process conditions, it is proposed that when the hot-melt adhesive varnish layers are pressurized in the axial direction of the stacked sheet metal parts, they are pressurized multiple times by means of a pressure pulse in that the pressure pulse is exerted through either an impingement with pulse pressure or a relief of pulse pressure.

Proposed is a method for producing a grain-oriented electromagnetic steel sheet, with which it is possible to further improve magnetic properties and suppress fluctuations in magnetic properties and film properties in a coil without using an inhibitor. This method for producing a grain-oriented electromagnetic steel sheet includes: a hot rolling step for hot rolling a steel roll material having a constituent composition which contains C, Si, Mn, acid-soluble Al, N and Sb and in which S and Se are contained so as to satisfy a prescribed relational expression; an optional hot-rolled sheet annealing step; a cold rolling step; an acid washing step; a primary recrystallization annealing step; and a finish annealing step. In intermediate annealing in the hot-rolled sheet annealing step or cold rolling step before a final cold rolled steel sheet is obtained, the γ-phase fraction in the steel structure at the annealing temperature is 1.0-25.0 vol%, the average cooling speed after annealing is 20-50ºC / s, acid washing is carried out using a solution which contains 2-15 mass% of Fe ions and has an acid concentration of 1-20 mass% in the acid washing step, and an annealing separating agent contains a Ti compound at a quantity of 0.3-8 parts by mass in terms of Ti relative to 100 parts by mass of magnesia in the finish annealing step.