JP6518950B2 - Non-oriented electrical steel sheet and method of manufacturing the same - Google Patents

Description

  The present invention relates to a non-oriented electrical steel sheet, and more particularly to a non-oriented electrical steel sheet excellent in magnetic characteristics suitable for use as an electrical material, such as a core of a motor or a transformer.

  Non-oriented electrical steel sheets having excellent magnetic properties are mainly used as drive motors for electric vehicles and motors for home appliances. Such non-oriented electrical steel sheets are required to have a low core loss to improve the energy usage efficiency of the motor and a high magnetic flux density to miniaturize the motor. In order to reduce the {111} plane orientation which is disadvantageous to the improvement of the magnetic properties in response to such requirements, the grain size of the crystal grains in the steel plate before cold rolling is coarsened or hot rolled. Methods have been taken to make the resulting hot-rolled sheet as thin as possible to reduce the rolling reduction in cold rolling. In addition, attempts have been made to reduce the amount of impurities in the steel as much as possible and to suppress the increase in hysteresis loss due to the formation of precipitates.

  There is also known a technique for obtaining extremely high magnetic flux density by high temperature annealing in vacuum. This uses a mechanism in which grains with low surface energy {100} plane orientation or {110} plane orientation grow by attacking grains with other surface energy higher orientation in vacuum. It is According to this technique, a non-oriented electrical steel sheet having a high magnetic flux density can be obtained without adding Si or Al, so a non-oriented electrical steel sheet having good magnetism regardless of the trend of alloy cost Has the advantage of being able to produce

As a technique for obtaining a high magnetic flux density by performing high temperature finish annealing in vacuum, for example, Patent Document 1 adds nitride and sulfide in steel in addition to the annealing temperature in finish annealing and the degree of vacuum of the atmosphere. A technique is disclosed to form a {100} texture and obtain very good magnetic flux density B ₅₀ and iron loss W _15/100 by reducing as much as possible. According to Patent Document 2, abnormal grain growth using surface energy occurs by reducing oxygen to a predetermined concentration or less in an atmosphere mainly composed of a reducing atmosphere containing hydrogen and an inert gas such as nitrogen and Ar. A technique is disclosed for obtaining coarse grains of Goss orientation ({110} <001> orientation) advantageous to the characteristics.

  However, the above technique has a problem that the low frequency iron loss is high when the excitation frequency is 50 Hz. And when iron loss was divided into hysteresis loss and eddy current loss and examined, it was found that hysteresis loss was not reduced so much.

JP 2001-131642 A JP-A-7-76734

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-oriented electrical steel sheet having a low low frequency core loss and a high magnetic flux density and a method of manufacturing the same.

  MEANS TO SOLVE THE PROBLEM The present inventors surfaced the cold rolled sheet as a result of carrying out high temperature annealing of the cold rolled sheet obtained by changing the surface roughness of the work roll of cold rolling in an extremely low oxygen atmosphere in order to solve the said subject. It has been found that the hysteresis loss can be reduced by reducing the roughness.

The experiments that triggered the present invention are shown below.
In mass%, C: 0.0013%, Si: 3.0%, P: 0.01%, Mn: 0.10%, Al: 0.50%, S: 0.0010%, N: 0. A molten steel with a component composition containing 0015%, Cu: 0.010%, and the balance of Fe and unavoidable impurities is laboratory melted and cast, and then hot rolled to a thickness of 2.0 mm. It was a hot-rolled sheet. Thereafter, the hot-rolled sheet is subjected to hot-rolled sheet annealing at 1050 ° C. for 60 seconds, pickled, and then cold-rolled to 0.20 mm to obtain a cold-rolled sheet. At this time, by changing the roughness of the work roll of the rolling mill used for cold rolling to 1.2 μm to 0.2 μm, cold rolled sheets having different steel sheet surface roughness were obtained. Thereafter, the cold rolled sheet is subjected to finish annealing in which the soaking temperature is 1150 ° C. in a vacuum of 0.1 Pa and the soaking time (the holding time at the soaking temperature) is changed between 1 to 120 minutes An annealed sheet was obtained. The surface roughness Ra of the steel sheet of the finished annealed sheet was measured by a laser roughness meter. Thereafter, the finished annealed sheet was processed into a ring sample having an inner diameter of 60 mm and an outer diameter of 80 mm by wire cutting. Then, the 35 ring samples are stacked in a ceramic ring case, and a primary winding of 100 turns and a secondary winding of 20 turns are applied to the ring-shaped magnetic measurement sample for magnetic measurement did. The core loss W _15/50 at a frequency of 50 Hz and a maximum magnetic flux density of 1.5 T was measured by an AC magnetic measurement apparatus using the ring-shaped magnetic measurement sample. Moreover, the hysteresis loss in maximum magnetic flux density 1.5T was measured by the direct current | flow magnetization measuring apparatus using the said ring-shaped magnetism measurement sample.

  FIG. 1 shows the relationship between the finish annealing time (soaking time) and the iron loss. Although the core loss decreases with the finish annealing time, in the steel sheet having a high surface roughness Ra of the steel sheet, the change in the core loss is almost lost in the annealing of 60 minutes or more. On the other hand, it was found that the iron loss continued to decrease with the finish annealing time in the material having a low steel sheet surface roughness Ra, and it was possible to greatly reduce the iron loss by reducing the steel sheet surface roughness Ra. The relationship between finish annealing time, hysteresis loss, and average grain size is shown in FIGS. As shown in FIG. 2, it was found that the hysteresis loss decreases with the finish annealing time, but the reduction effect of the hysteresis loss is large in the material having a low steel surface roughness Ra. Moreover, as shown in FIG. 3, the average grain size of the steel plate increased with the finish annealing time.

  It is generally known that hysteresis loss decreases as the grain size increases. However, according to this experiment, even if the grain size is increased by finish annealing, the reduction effect of the hysteresis loss may not be sufficiently obtained, and the reduction of the surface roughness of the steel sheet reduces the hysteresis loss. It was found that the iron loss can be sufficiently reduced without the effect being suppressed.

  From the above results, the present invention is further based on the technical idea that the hysteresis loss is reduced by reducing the surface roughness of the cold-rolled sheet before finish annealing in vacuum, and the other various conditions are appropriate. Was completed by

The means of the present invention for solving the above problems is as follows.
[1] mass%, C: 0.005% or less, Si: 1.0% to 6.0%, Mn: 0.01% to 2.5%, P: 0.5% or less, Al : 1.0% or less, N: 0.005% or less, Cu: 0.005% or more and 1.0% or less, and S: 0.0005% or more and 0.005% or less, and Cu and S The product of mass%, Cu x S, satisfies 5 x ^10-6 <Cu x S <5 x ^10-4 and has a component composition consisting of the balance Fe and unavoidable impurities, and {100} crystal face of crystal grains The ratio of the crystal grains having the {100} plane orientation is defined as the crystal grains having the size of the angle (β angle) between the steel and the rolling surface within 3 ° as the crystal grains having the {100} plane orientation. In the crystal grain having an area ratio of 70% or more and having the {100} plane orientation, an angle between the <012> axis and the rolling direction The percentage of crystal grains whose size is less than 10 ° is 70% or more in area ratio, the surface roughness Ra of the steel plate is 0.40 μm or less, and the plate thickness is 0.05 mm or more and 0.25 mm or less Non-oriented electrical steel sheet characterized by
[2] Iron loss W _{15/50 at a} frequency of 50 Hz and a maximum magnetic flux density of 1.5 T is 1.8 W / kg or less, and a magnetic flux density B ₅₀ at a magnetic field strength of 5000 A / m is 1.77 T or more The non-oriented electrical steel sheet according to [1], characterized in that
[3] The method for producing a non-oriented electrical steel sheet according to [1] or [2], which comprises hot rolling a slab having the above-mentioned component composition and then sandwiching one cold rolling or intermediate annealing 2 After cold rolling is performed several times or more to obtain a cold rolled sheet having a final plate thickness of 0.05 mm or more and 0.25 mm or less and a surface roughness Ra of 0.40 μm or less in the cold rolling, 10 Pa or less A method of manufacturing a non-oriented electrical steel sheet characterized by performing finish annealing in a vacuum or inert gas atmosphere at a soaking temperature of 1050 ° C. or more for 0.5 hour or more.

  According to the present invention, it is possible to provide a non-oriented electrical steel sheet which is low in low frequency core loss and excellent in magnetic properties with a high magnetic flux density, and a method of manufacturing the same.

FIG. 1 is a graph showing the relationship between finish annealing time and core loss. FIG. 2 is a graph showing the relationship between finish annealing time and hysteresis loss. FIG. 3 is a graph showing the relationship between finish annealing time and average grain size.

  Hereinafter, the non-oriented electrical steel sheet of the present invention and the method for producing the same will be described in detail. First, the component composition of the non-oriented electrical steel sheet of the present invention will be described. Hereinafter, mass% is simply expressed as% unless otherwise specified.

Ingredient composition:
C: 0.005% or less When the content of C is large, magnetic aging occurs to deteriorate the magnetic characteristics, so the content of C is set to 0.005% or less. A further preferred range is 0.003% or less. On the other hand, it is preferable to set the content of C to 0.00005% or more because the cost is increased if the content of C is extremely reduced.

Si: 1.0% or more and 6.0% or less Si is an element that increases the specific resistance of steel, and addition of 1.0% or more is essential in that it is possible to improve eddy current loss. is there. On the other hand, if it is added excessively, the magnetic flux density is reduced to 6.0% or less. A more preferable range is 1.5% or more and 4.0% or less from the viewpoint of enhancing the productivity.

Mn: 0.01% or more and 2.5% or less Mn is an element that increases the specific resistance of steel, and addition of 0.01% or more is essential in that it is possible to improve eddy current loss. is there. On the other hand, if it is added excessively, the cost increases, so the content is made 2.5% or less. Preferably it is 0.04% or more and 2.0% or less.

P: 0.5% or less P is an element having the effect of strengthening the steel sheet and improving the punching property. On the other hand, in order to embrittle the steel sheet if it is added excessively, the upper limit is made 0.5%. Preferably, the content of P is 0.1% or less.

S: 0.0005% or more and 0.005% or less S is an element essential for forming CuS and suppressing grain growth during heating of finish annealing. If the crystal grains become too large in the heating process of the final annealing, the crystal grains in the orientation where the angle (β angle) between the {100} crystal plane and the rolling plane forms at the start of abnormal grain growth increases (becomes more than 3 °) As a result, after abnormal grain growth, a texture advantageous to the magnetic properties can not be obtained, and the magnetic properties are degraded. The lower limit is made 0.0005% in order to obtain texture which is advantageous to the magnetic properties. In addition, the upper limit is made 0.005% because the magnetic properties deteriorate if it is added excessively.
Furthermore, in the present invention, the product (Cu × S) of mass% of Cu and S is set to 5 × 10 ⁻⁶ <Cu × in order to make the texture advantageous to the magnetic properties after abnormal grain growth and improve the magnetic properties. It is set as the range of S <5 * 10 < ^-4 >.

Al: 1.0% or less Al, like Si, is an element that increases the specific resistance of steel, and is an element that is effective to reduce iron loss. In addition, from the viewpoint of controlling crystal grain growth, formation of AlN suppresses the growth of crystal grains before abnormal grain growth. On the other hand, the mechanical properties are deteriorated if it is added excessively, so the content of Al is made 1.0% or less.

N: 0.005% or less N forms nitrides with Al and Si and degrades the magnetic properties, so the N content is made 0.005% or less. More preferably, it is 0.003% or less.

Cu: 0.005% or more and 1.0% or less Cu is an essential element for forming CuS and suppressing grain growth during heating of finish annealing. In order to obtain a texture which is advantageous to the in-plane magnetic properties by finish annealing, it is necessary to control grain growth appropriately in the heating process of finish annealing, so the lower limit is made 0.005%. On the other hand, the excessive addition thereof degrades the magnetic properties, so the upper limit is made 1.0%. More preferably, it is 0.01% or more and 0.5% or less. Also, as described above, in the present invention, the product of mass% of Cu and S (Cu to control grain growth of the crystal during heating of finish annealing and improve the magnetic property as a texture advantageous to the magnetic property) Let xS) be in the range of 5 × 10 ⁻⁶ <Cu × S <5 × 10 ⁻⁴ .

  Even if it is an element except having shown above, if it is the unavoidable impurity which can not be removed industrially, even if it contains, there is no problem. For example, elements other than the above may be contained if the total amount is less than about 0.05%. However, Ti, Nb, V, and Zr each preferably have a content of less than 0.001% in order to form carbonitrides and sulfides that cause deterioration of the magnetic properties.

Crystal orientation:
The non-oriented electrical steel sheet of the present invention is characterized in that crystal grains having a {100} plane orientation are preferentially present in the crystal orientation. The crystal grain having the {100} plane orientation means that the angle (β angle) between the {100} crystal plane in the crystal and the rolling plane as measured by X-ray single crystal orientation measurement is within 3 ° Define. However, this β angle is the smallest of the angles that three equivalent {100} crystal planes make with the rolling surface. Further, the higher the abundance ratio of crystal grains having the {100} plane orientation, the better, and the ratio of crystal grains having the {100} plane orientation is 70% or more in area ratio. More preferably, it is 80% or more.

  The non-oriented electrical steel sheet of the present invention is also characterized in that the <012> axis of the crystal grain having the {100} plane orientation is aligned with the rolling direction. Specifically, among crystal grains having {100} orientation, the ratio of crystal grains having an angle (α angle) between the <012> axis and the rolling direction within 10 ° is 70% in area ratio That is, the ratio of crystal grains whose size of the α angle is 0 to 5 ° is also 60% or more. The non-oriented electrical steel sheet of the present invention has such a crystallographically oriented structure, so that extremely good magnetic properties can be obtained in the in-plane rolling direction.

  In the present invention, the area ratio of crystal grains having a {100} orientation and the area ratio of crystal grains having an α-angle size within 10 ° of the crystal grains are the product plate (non-oriented electrical steel sheet The specimen is collected from X), and the range of 300 mm × 200 mm is measured at a pitch of 7 mm by X-ray single crystal orientation measurement, the area of crystal grains having {100} plane orientation, and the size of α angle among the crystal grains The area of crystal grains within 10 ° is measured and determined.

Average grain size:
The non-oriented electrical steel sheet of the present invention was surface-polished and then chemically etched to prepare a sample, and then the average crystal grain size was measured by observing the sample surface with an optical microscope. Here, the average grain size is defined as Σdi × Si, where di is the grain size in the rolling direction of one crystal grain i (RD grain size) and Si is the area ratio. In particular, in crystal grains having an RD grain size of 1 mm or more, observation of grain boundaries is difficult with an optical microscope. Therefore, the misorientation between adjacent crystal grains (difference in α angle and β If the difference between the angles) was within 0.5 °, there were no grain boundaries between adjacent crystal grains, and it was judged that the adjacent crystal grains were contained in the same crystal grain.

Then, the manufacturing method of the non-oriented electrical steel sheet concerning the present invention is shown below.
First, the slab prepared to have the above-mentioned component composition in the steel making process is reheated at 1200 ° C. or less. If the temperature is higher than 1200 ° C., fine dispersion of MnS and AlN causing grain growth suppression may occur, and appropriate grain growth can not be controlled in the heating process of finish annealing, and a texture favorable to magnetic characteristics may not be obtained. There is. More preferably, it is 1150 ° C. or less.

  After reheating, hot rolling is performed. The winding temperature is preferably 700 ° C. or less. When the coiling temperature is excessively high, fine dispersion of AlN or the like occurs. The finished plate thickness in hot rolling is preferably thin, and is preferably 3.0 mm or less. This is because when the finished plate thickness in hot rolling is large, the cold rolling reduction ratio in the subsequent cold rolling becomes high, and the crystal grains of {111} crystal plane orientation, which is undesirable for the magnetic characteristics, increase.

  After hot rolling, hot rolled sheet annealing may or may not be performed on the hot rolled sheet obtained by hot rolling. In the case of hot-rolled sheet annealing, although the magnetic characteristics show slightly better values, there is also a disadvantage that the cost increases.

  In addition, when the cold rolling reduction ratio in the subsequent cold rolling becomes excessively high such as 95% or more, hot rolled sheet annealing may be performed to soften the hot rolled sheet to reduce cold rolling load. preferable. When hot-rolled sheet annealing is performed, it is performed in a hydrogen atmosphere or an Ar atmosphere. When annealing is performed in a nitrogen atmosphere, nitrogen intrudes into the base iron to precipitate silicon nitride which causes the deterioration of the magnetic characteristics.

  Subsequently, the scale is removed from the surface of the hot-rolled sheet obtained by the hot rolling or the surface of the hot-rolled and annealed sheet subjected to the hot-rolled sheet annealing by a usual method such as shot blasting or hydrochloric acid pickling Then, cold rolling is performed once or twice, and the final thickness is obtained. The term "cold rolling twice or more" refers to sandwiching an intermediate annealing process in the middle of cold rolling. The rolling reduction of the final cold rolling (for example, the second cold rolling when cold rolling is performed twice) is preferably 40% or more. If the final cold rolling reduction is less than 40%, the grains are excessively coarsened, and during the subsequent finish annealing, the growth driving force of the grains having {100} orientation that is advantageous for the magnetic properties is It is because it becomes smaller. More preferably, it is 50% or more.

  The thickness after cold rolling, which is the final thickness, is 0.05 mm or more and 0.25 mm or less. If the plate thickness is excessively large, in the subsequent finish annealing, grains having a {100} plane orientation are not sufficiently formed. It is presumed that this is because the driving force of surface energy is lower than the grain growth driving force of other plane orientations. If the thickness is too thin, not only cold rolling load will increase but also the handling of the steel sheet will be impaired, bending deformation and the like will tend to occur, which is undesirable because it degrades the magnetic properties.

  The surface roughness Ra of the steel plate after cold rolling is 0.40 μm or less. If Ra is larger than 0.40 μm, even if the crystal grains are coarsened by annealing, the reduction effect of the hysteresis loss due to the crystal coarsening is saturated as in the above-mentioned experiment, but the surface roughness Ra of the steel sheet is By setting the thickness to 0.40 μm or less, a further reduction effect of hysteresis loss can be obtained. The surface roughness of the steel plate can be adjusted by changing the surface roughness of the work roll of a rolling mill used for cold rolling. When the rolling mill is a tandem mill, it is preferable to adjust the surface roughness of the work roll of the final stand.

  When performing intermediate annealing in the middle of cold rolling, it carries out by carrying out by hydrogen atmosphere or Ar atmosphere like hot-rolled sheet annealing. The intermediate annealing may be performed at a temperature at which the structure softens, but is more preferably performed at 800 ° C. or higher. This is to coarsen the structure to increase the area ratio of the crystal orientation preferred for improving the magnetic properties in the first half of the finish annealing. More preferably, it is 900 ° C. or higher.

In addition, after the completion of the hot rolling process and before the finish annealing process, if necessary, the pickling process is performed separately from the above scale removal, and oxides inevitably formed on the surface are surface oxygen It is preferable to adjust until the (O-Kα) count value becomes 250/70 msec or less.
Here, the surface oxygen (O-K.alpha.) Count value is an electron beam microanalyzer (ERAX 6600 MX manufactured by JEOL) with an acceleration voltage of 3 kV, a beam current of 120 nA, and a beam diameter of 100 .mu.m. This is a value obtained by measuring the Kα line of oxygen while performing stage scanning of a 20 mm square area with 200 points × 200 points at a pitch of 100 μm and a measurement time of 70 msec per point. Such an oxide may be generated during the hot rolling, during the hot-rolled sheet annealing, or during the intermediate annealing during the cold rolling due to the presence of water and oxygen which are inevitably mixed. Although SiO ₂ and Fe ₂ SiO ₄ are recognized as the form of the oxide, they can be removed by pickling with hydrogen fluoride water or a mixed solution with an acid such as hydrochloric acid.

  The cold rolled sheet cold rolled to the final thickness is subjected to finish annealing in a vacuum of 10 Pa or less or in an inert gas atmosphere. Here, the inert gas is a gas with low reactivity with the surface of the steel plate such as nitrogen or argon, and the inert gas is supplied into the furnace to reduce the oxygen partial pressure, thereby making the furnace vacuum. The same effect is obtained. Moreover, the oxygen partial pressure in a furnace can also be further reduced by mixing highly reducing gas, such as hydrogen, in this inert gas. If the degree of vacuum is excessively low, the size of the pump equipment and the like becomes large and the manufacturing cost increases, so the lower limit is about 0.005 Pa.

  Moreover, in finish annealing, it is preferable from the viewpoint of productivity that the average temperature rising rate up to the highest reaching temperature be 30 ° C./hr or more. More preferably, it is 500 ° C./hr or more. The maximum temperature (soaking temperature) in the final annealing is 1050 ° C. or more, and the holding time (soaking time) at 1050 ° C. or more is 0.5 hr or more, more preferably 1.0 hr or more. If the soaking temperature is less than 1050 ° C., abnormal grain growth in finish annealing is insufficient, and a texture favorable to magnetic properties can not be obtained. In addition, when the soaking time is less than 0.5 hr, abnormal grain growth in finish annealing is insufficient, and a texture favorable to magnetic properties can not be obtained.

% By mass, C: 0.001%, Si: 1.1% to 5.5%, Mn: 0.01% to 2.4%, P: 0.01%, Al: 0.001%, N Molten steel of the component composition which changes the component composition in the range of 0.001%, Cu: 0.001% to 1.0%, S: 0.0001% to 0.02%, and the balance of Fe and unavoidable impurities Were laboratory-melted and cast, and then hot-rolled to form a 2.0 mm-thick hot-rolled sheet. Thereafter, the hot-rolled sheet is subjected to hot-rolled sheet annealing at 1000 ° C. for 60 seconds, pickled, and then cold-rolled by a rolling mill with a work roll roughness of 0.2 μm. A rolled plate of 2 μm was obtained. The finished thickness (final thickness) of the cold rolled sheet in the cold rolling was changed in the range of 0.05 mm to 0.30 mm. Thereafter, the cold-rolled sheet was subjected to finish annealing in a pressure of 0.01 Pa (vacuum), 20 Pa (low vacuum degree), a nitrogen or argon atmosphere of purity 99.999%. Here, the soaking temperature of the finish annealing is 900 to 1100 ° C., and the soaking time is 6 to 60 minutes. The crystal orientation of the finish annealed sheet (non-oriented electrical steel sheet) after the finish annealing was measured by X-ray single crystal orientation measurement. Thereafter, the finished annealed sheet was processed into a ring sample having an inner diameter of 60 mm and an outer diameter of 80 mm by wire cutting. Then, the 35 ring samples are stacked in a ceramic ring case, and a primary winding of 100 turns and a secondary winding of 20 turns are applied to the ring-shaped magnetic measurement sample for magnetic measurement did. An iron loss W _15/50 at a frequency of 50 Hz and a maximum magnetic flux density of 1.5 T and a magnetic flux density B ₅₀ at a magnetizing force of 5000 A / m were measured by an AC magnetic measuring apparatus using the ring-shaped magnetic measurement sample.

  The measurement results, the composition of the steel, the final thickness of the cold rolled sheet in cold rolling, and the final annealing conditions are shown in Table 1. From Table 1, it can be seen that the non-oriented electrical steel sheet manufactured under the conditions compatible with the present invention has improved crystal orientation after abnormal grain growth and has excellent magnetic properties.

Claims (3)

C: 0.005% or less, Si: 1.0% to 6.0%, Mn: 0.01% to 2.5%, P: 0.5% or less, Al: 1.% by mass. 0% or less, N: 0.005% or less, Cu: 0.005% or more and 1.0% or less, and S: 0.0005% or more and 0.005% or less are contained, and the mass% of Cu and S The product Cu × S satisfies 5 × 10 ⁻⁶ <Cu × S <5 × 10 ⁻⁴ and has a component composition including the balance Fe and unavoidable impurities,
When a crystal grain whose size (β angle) between the {100} crystal plane of the crystal grain and the rolling plane is within 3 ° is defined as a crystal grain having a {100} plane orientation, the {100} plane The ratio of crystal grains having an orientation is 70% or more in area ratio, and among the crystal grains having the {100} plane orientation, the size of the angle (α angle) between the <012> axis and the rolling direction is The ratio of crystal grains within 10 ° is 70% or more in area ratio,
A non-oriented electrical steel sheet characterized in that the surface roughness Ra of the steel sheet is 0.40 μm or less and the thickness is 0.05 mm or more and 0.25 mm or less. Core loss W _{15/50 at a} frequency of 50 Hz and a maximum magnetic flux density of 1.5 T is 1.8 W / kg or less, and a magnetic flux density B ₅₀ at a magnetic field strength of 5000 A / m is 1.77 T or more The non-oriented electrical steel sheet according to claim 1, wherein A method of manufacturing a non-oriented electrical steel sheet according to claim 1 or 2,
After hot rolling a slab having the above-mentioned composition, cold rolling is performed once or twice or more with intermediate annealing interposed, and the final plate thickness in the cold rolling is 0.05 mm or more 0 After obtaining a cold-rolled sheet of 25 mm or less and surface roughness Ra of 0.40 μm or less, finish annealing is performed by holding it for 0.5 hour or more at a soaking temperature of 1050 ° C. or more in a vacuum of 10 Pa or less or inert gas atmosphere. A method of manufacturing a non-oriented electrical steel sheet characterized by performing.

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