JP6658150B2 - Magnetic steel sheet - Google Patents

Description

  The present invention relates to an electromagnetic steel sheet effective for improving the performance of a rotating machine such as a motor and a generator.

  In recent years, global warming issues, environmental pollution issues, and energy issues have attracted increasing interest. In order to solve these problems, it has become an important issue to improve the efficiency of motors and generators used in many electric appliances. Specifically, there is a need to improve the magnetic properties of magnetic steel sheets, which are iron core materials for motors and generators.

  Further, with the development of power electronics, the number of motors and generators that utilize the driving frequency of a motor and a generator in a high frequency range exceeding the conventional commercial frequency range is increasing. For this reason, there has been an increasing demand for electromagnetic steel sheets used for iron core materials that have low iron loss not only in a low frequency range but also in a high frequency range. In particular, in a compressor motor of an air conditioner and a refrigerator, or a drive motor or a generator of a hybrid electric vehicle (HEV) and an electric vehicle (Electric: Vehicle: EV), iron loss in a high frequency range is low and high magnetic flux density is high. Therefore, there is a demand for an electromagnetic steel sheet. Further, the demand for the material strength of an electromagnetic steel sheet that can withstand high-speed rotation during high-frequency driving is becoming increasingly severe.

  In order to reduce iron loss (especially high-frequency iron loss), it is effective, for example, to make the magnetic steel sheet highly alloyed and reduce eddy current loss by increasing the specific resistance. Further, solid solution strengthening by high alloying also contributes to an increase in strength of the electromagnetic steel sheet. However, an increase in the amount of alloy in the magnetic steel sheet lowers the magnetic flux density, so that it was difficult to achieve both low iron loss and high strength and high magnetic flux density.

  In order to solve the above problems, for example, in Patent Document 1 below, Si: 2.5% to 4.5% and Mn: 0.005% to 1.0% by mass%. An electromagnetic steel sheet containing, and having an Al content of 200 ppm or less, S, N, and O contents of 30 ppm or less, respectively, and the balance being substantially Fe, and having an average crystal grain size of 0.05 mm. 0.50 mm, and the area ratio of crystal grains having an azimuth difference from the {110} <001> orientation within 20 ° is 25% to 75%, and the tensile strength is 400 MPa or more. An electromagnetic steel sheet for a motor core having excellent high-frequency magnetic characteristics and mechanical strength characteristics has been proposed.

  In addition, in Patent Document 1, in addition to the above features, P: 0.005% to 0.20%, Ni: 0.01% to 3.50%, and Sn: 0.01% to 0% by mass%. .20%, Sb: 0.005% to 0.50%, Cu: 0.01% to 0.50%, and Cr: 0.01% to 1.50% Electrical steel sheets further containing elements have also been proposed.

In the following Patent Document 2, in mass%, Si: 0.8% to 2.5%, Mn: 0.1% to 2.5%, sol. Al: 1.5% or less, P: 0.005% to 0.30%, or Ni: 0.05% to 1.5%. and consists of inevitable impurities, the product of the density of the mass fraction and the steel of Fe 7.35 or more, 1.70T or more flux density _{B 50,} yield strength of 300MPa or more, and, 0.15 mm thick A non-oriented electrical steel sheet characterized by being at least 0.40 mm or less has been proposed.

JP-A-2002-146491 JP-A-2002-371340

  However, the electromagnetic steel sheet disclosed in Patent Document 1 described above has a large variation in magnetic properties due to a low Al content. Also, when the strength of the magnetic steel sheet was increased, the dimensional accuracy at the time of punching was not at a satisfactory level.

  Further, in the electromagnetic steel sheet disclosed in Patent Document 2, since the content of Si is small, compatibility between high-frequency iron loss and mechanical properties was not at a satisfactory level. Further, when the strength of the magnetic steel sheet was increased, the dimensional accuracy at the time of punching was not at a satisfactory level.

  Therefore, the present invention has been made in view of the above-described problems, and it is an object of the present invention to provide an electromagnetic coil having low iron loss, high magnetic flux density and high strength, and excellent dimensional accuracy during punching. It is to provide a steel plate.

  The present inventors added an iron having a high solid solution strengthening ability in an amount of 3.0% by mass or more and 4.0% by mass or less by adding an iron having a high solid solution strengthening ability by increasing an electric resistance, thereby improving a solid solution strengthening ability and a magnetic flux density improving effect. Is added in an amount of 0.03% by mass or more and 0.15% by mass or less, and an appropriate amount of Al and Mn is further added, whereby 3.5% by mass ≦ Si + Al + 0.5 × Mn ≦ 5.0% by mass. It has been found that by using a high alloy material, it is possible to improve high-frequency iron loss and increase strength while suppressing a reduction in magnetic flux density.

  However, it has been found that the dimensional accuracy at the time of punching is inferior to the electromagnetic steel sheet having a yield strength of 400 MPa or more. Therefore, further investigation was performed including the dimensional accuracy at the time of punching. As a result, in the X-ray diffraction profile measured on the steel sheet surface, by controlling the peak half width of the (211) plane to 0.16 ° or less, improvement in dimensional accuracy at the time of punching can be obtained. I found it. By referring to these findings, the present inventors have found that an electromagnetic steel sheet having excellent magnetic properties, mechanical properties, and dimensional accuracy can be obtained.

  The gist of the present invention completed based on the above findings is as follows.

  (1) In mass%, C: 0.005% or less, Si: 3.0% or more and 4.0% or less, Mn: 3.0% or less, S: 0.004% or less, sol. Al: 0.1% or more and 1.5% or less, P: 0.03% or more and 0.15% or less, the balance being Fe and impurities, 3.5% ≦ Si + Al + 0.5 × Mn ≦ 5. 0%, the yield strength is 400 MPa or more, and the peak half width of the (211) plane in the X-ray diffraction profile measured on the steel sheet surface is 0.16 ° or less.

  (2) In mass%, C: 0.005% or less, Si: 3.0% or more and 4.0% or less, Mn: 3.0% or less, S: 0.004% or less, sol. 2. Al: 0.1% or more and 1.5% or less, P: 0.03% or more and 0.15% or less, Sn: 0.001 to 0.15%, the balance being Fe and impurities. 5% ≦ Si + Al + 0.5 × Mn ≦ 5.0%, the yield strength is 400 MPa or more, and the peak half width at (211) plane of the X-ray diffraction profile measured on the steel sheet surface is 0.16 ° or less. There is an electrical steel sheet.

  As described above, according to the present invention, it is possible to provide an electromagnetic steel sheet having high magnetic flux density, low high-frequency iron loss, high strength, and good dimensional accuracy at the time of punching.

FIG. 4 is a schematic diagram illustrating a peak half width in an X-ray diffraction profile. It is a graph which shows the influence of the yield strength on the dimensional accuracy at the time of a punching process, and the peak half value width of a (211) plane.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  The present inventors have succeeded in obtaining an electrical steel sheet having excellent magnetic properties, mechanical properties and workability by drastically reviewing the chemical composition and the shape of the X-ray diffraction profile measured on the steel sheet surface. .

  The electromagnetic steel sheet according to one embodiment of the present invention is as follows. The electrical steel sheet according to the present embodiment is specifically a non-oriented electrical steel sheet having the following features.

  (1) In mass%, C: 0.005% or less, Si: 3.0% or more and 4.0% or less, Mn: 3.0% or less, S: 0.004% or less, sol. Al: 0.1% or more and 1.5% or less, P: 0.03% or more and 0.15% or less, the balance being Fe and impurities, 3.5% ≦ Si + Al + 0.5 × Mn ≦ 5. 0%, the yield strength is 400 MPa or more, and the peak half width of the (211) plane in the X-ray diffraction profile measured on the steel sheet surface is 0.16 ° or less.

  (2) In mass%, C: 0.005% or less, Si: 3.0% or more and 4.0% or less, Mn: 3.0% or less, S: 0.004% or less, sol. Al: 0.1% to 1.5%, P: 0.03% to 0.15%, Sn: 0.001% to 0.15%, the balance being Fe and impurities, 3.5% ≦ Si + Al + 0.5 × Mn ≦ 5.0%, the yield strength is 400 MPa or more, and the peak half width of the (211) plane in the X-ray diffraction profile measured on the steel sheet surface is 0.16 °. The following is an electrical steel sheet.

<1. Chemical composition of steel>
Hereinafter, first, the chemical composition of the steel of the electromagnetic steel sheet according to the present embodiment will be described in detail. In the following, unless otherwise specified, the notation “%” means “% by mass”. In the chemical composition of the steel of the electromagnetic steel sheet according to the present embodiment, the balance other than the elements described below consists of Fe and impurities.

[C: 0.005% or less]
C (carbon) is an element that causes iron loss deterioration. Therefore, in the magnetic steel sheet according to the present embodiment, the upper limit of the content of C is set to 0.005%. If the content of C exceeds 0.005%, iron loss is deteriorated in the electromagnetic steel sheet, and good magnetic properties cannot be obtained, which is not preferable. The content of C is desirably 0.004% or less, and more desirably 0.003% or less. The lower the C content, the better. The lower limit of the C content is not particularly limited, but is, for example, 0.0001%.

[Si: 3.0% or more and 4.0% or less]
Si (silicon) is an element that increases the electrical resistance of steel to reduce eddy current loss and improve high-frequency iron loss. Further, Si has a large solid solution strengthening ability, and is therefore an effective element for increasing the strength of an electromagnetic steel sheet. In order to sufficiently exhibit these effects, it is necessary to contain 3.0% or more of Si. However, when the content of Si exceeds 4.0%, the workability of the magnetic steel sheet is significantly deteriorated, and thus, for example, it becomes difficult to cold-roll the magnetic steel sheet. Therefore, the upper limit of the content of Si is set to 4.0%. The content of Si is desirably from 3.1% to 3.9%, and more desirably from 3.2% to 3.8%.

[Mn: 3.0% or less]
Mn (manganese) is an element effective for increasing the electric resistance of steel to reduce eddy current loss and improve high frequency iron loss. However, when the content of Mn exceeds 3.0%, the magnetic flux density is remarkably reduced, so the upper limit of the content of Mn is set to 3.0%. The Mn content is desirably 2.6% or less, and more desirably 2.2% or less. In addition, even when the content of Mn is small, if the electrical resistance is increased by increasing the content of Si and Al, the high-frequency iron loss of the magnetic steel sheet can be reduced, so the lower limit of the content of Mn is particularly limited. Although not performed, for example, it is 0.01%.

[Sol. Al (acid-soluble Al): 0.1% or more and 1.5% or less]
Al (aluminum) is an element effective for increasing eddy current loss by increasing the electrical resistance of the electromagnetic steel sheet and improving high-frequency iron loss. sol. When the content of Al (also simply referred to as Al) is less than 0.1%, the effect of increasing the electric resistance is small, and AlN is finely precipitated in the magnetic steel sheet, so that the crystal grains become fine. Adversely affects iron loss. Therefore, the lower limit of the Al content is 0.1%. On the other hand, when the content of Al exceeds 1.5%, the magnetic flux density of the magnetic steel sheet significantly decreases. Therefore, the content of Al is set to 0.1% or more and 1.5% or less. The content of Al is desirably 0.2% or more and 1.4% or less, and more desirably 0.3% or more and 1.3% or less.

[P: 0.03% or more and 0.15% or less]
Since P (phosphorus) has a large solid solution strengthening ability and also has an effect of increasing {100} texture, which is advantageous for improving magnetic properties, it is extremely effective in achieving both high strength and high magnetic flux density. Element. Further, since the increase in the {100} texture contributes to reducing the anisotropy of the mechanical properties in the plane of the steel sheet, P is an effect of improving the dimensional accuracy at the time of punching of the electromagnetic steel sheet. Also have. In order to obtain the effect of improving such strength, magnetic properties, and dimensional accuracy, it is necessary that P be contained in the electromagnetic steel sheet in an amount of 0.03% or more. However, when the content of P exceeds 0.15%, the ductility of the magnetic steel sheet is significantly reduced, so the upper limit of the content of P is 0.15%. The content of P is desirably 0.04% or more and 0.14% or less, and more desirably 0.05% or more and 0.13% or less.

[S: 0.004% or less]
S (sulfur) is an element that deteriorates the magnetic properties of the magnetic steel sheet by forming MnS. Therefore, the content of S is set to 0.004% or less. The content of S is desirably 0.003% or less, and more desirably 0.002% or less. The lower the content of S, the better. The lower limit of the content of S is not particularly limited, but is, for example, 0.0001%.

[Sn: 0.001% or more and 0.15% or less]
Sn (tin) is an element that improves magnetic properties by suppressing nitriding and oxidation of the surface layer portion of the electromagnetic steel sheet during finish annealing. Therefore, the steel constituting the electromagnetic steel sheet according to the present embodiment may further contain Sn. In order to obtain the above effect, the content of Sn needs to be 0.001% or more. On the other hand, when the Sn content exceeds 0.15%, the above-described effect is saturated. Therefore, when Sn is contained in the electromagnetic steel sheet according to the present embodiment, the Sn content is 0.001% or more and 0.15% or less. The Sn content is desirably from 0.005% to 0.14%, and more desirably from 0.01% to 0.13%.

[Si + Al + 0.5 × Mn: 3.5% or more and 5.0% or less]
In order to reduce iron loss (especially high-frequency iron loss), it is effective to add an alloy element (Si, Al and Mn) to increase electric resistance. Therefore, in the electromagnetic steel sheet according to the present embodiment, it is important that the sum of the contents of the alloying elements (Si, Al, and Mn) is within the above range. Since the increase in electric resistance per Mn content (unit%) is about half that of Si and Al, Si + Al + 0.5 × Mn was used as an index of the alloy addition amount. If Si + Al + 0.5 × Mn is less than 3.5%, sufficient electrical resistance cannot be obtained, and it becomes difficult for the electromagnetic steel sheet to achieve satisfactory high-frequency iron loss. On the other hand, if Si + Al + 0.5 × Mn exceeds 5.0%, the alloy element is too large, and the magnetic flux density of the magnetic steel sheet is significantly reduced. Therefore, Si + Al + 0.5 × Mn is set to 3.5% or more and 5.0% or less. Si + Al + 0.5 × Mn is desirably 3.6% or more and 4.9% or less, and more desirably 3.7% or more and 4.8% or less.

  In the magnetic steel sheet according to this embodiment, the content of elements such as Ni (nickel), Cr (chromium), Cu (copper), and Mo (molybdenum) other than the above-described elements is not particularly limited. The electromagnetic steel sheet according to the present embodiment has no particular problem even if these elements are contained at 0.3% or less. Further, in order to promote crystal grain growth during finish annealing of the electrical steel sheet, the electrical steel sheet according to the present embodiment may contain Ca (calcium) in a range of 30 ppm or less, and rare earth elements (Rare Earth Metal: REM) in the range of 100 ppm or less. Furthermore, the electromagnetic steel sheet according to the present embodiment may contain any element as an impurity as long as the effect of the present invention is not impaired.

<2. About yield strength>
[Yield strength: 400 MPa or more]
Next, the yield strength of the electromagnetic steel sheet according to the present embodiment will be described.

  2. Description of the Related Art In recent years, the number of rotations of a motor tends to increase more and more in order to reduce the size and increase the output of the motor. Since a large centrifugal force and repetitive stress are applied to the rotor core rotating at high speed, the possibility of deformation and fatigue failure of the rotor core has increased.

  In order to suppress such deformation and fatigue fracture of the rotor core, the yield strength of the electromagnetic steel sheet according to the present embodiment is 400 MPa or more. The yield strength of the magnetic steel sheet according to the present embodiment is desirably 410 MPa or more, and more desirably 420 MPa or more. In addition, from the viewpoint of further suppressing the deformation and fatigue fracture of the rotor core, the upper limit of the yield strength of the magnetic steel sheet is not particularly defined. However, when the yield strength of the magnetic steel sheet exceeds 800 MPa, the manufacturing cost increases, which is not desirable.

  In order to increase the yield strength of the electrical steel sheet and make it within the scope of the present invention, for example, it is necessary to increase the content of an element having a high solid solution strengthening ability such as Si or P, and to reduce the crystal grain size of the electrical steel sheet. May be used. However, if the crystal grain size is excessively reduced, iron loss deteriorates. Therefore, the crystal grain size needs to be controlled to an appropriate particle size that balances strength and iron loss.

  The yield strength can be measured, for example, by using a method described in JIS Z 2241. For example, the upper yield point of the electromagnetic steel sheet or the 0.2% proof stress that is the proof stress when a permanent elongation of 0.2% is caused may be obtained and used.

<3. Regarding peak half width in X-ray diffraction profile>
[Peak half width at (211) plane: 0.16 ° or less]
Subsequently, the shape of the X-ray diffraction profile of the magnetic steel sheet according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating a peak half width in an X-ray diffraction profile.

  The half width is, for example, the peak width at half the peak intensity Ip (Ip / 2) in the peak of the X-ray diffraction profile as shown in FIG. It is known that the peak half width in the X-ray diffraction profile increases in correlation with the occurrence of plastic strain. Although the above correlation is observed on various diffraction planes, the present inventors have conducted intensive studies on the peak of the (211) plane, and it is important to set the upper limit of the peak half width as described above. I found that.

  Specifically, in mass%, C: 0.002%, Si: 3.12%, Mn: 0.26%, P: 0.082%, S: 0.001%, sol. A 0.30 mm-thick electromagnetic steel sheet containing 0.65% of Al and 0.03% of Sn and the balance of Fe and impurities, C: 0.002%, and Si: 3.10% by mass% , Mn: 0.24%, P: 0.010%, S: 0.001%, sol. A 0.30 mm-thick electromagnetic steel sheet containing 0.62% of Al and 0.03% of Sn and the balance of Fe and impurities was punched, and the dimensional accuracy of the punched rotor core was investigated. .

  The yield strength of the former magnetic steel sheet is controlled in a range of 425 MPa to 435 MPa, and the yield strength of the latter magnetic steel sheet is controlled in a range of 385 MPa to 395 MPa by adjusting the temperature, tension, and cooling rate of the finish annealing. did. In addition, magnetic steel sheets were manufactured by changing the peak half-value width of the (211) plane, respectively, and punching was performed.

  The result is shown in FIG. FIG. 2 is a graph showing the influence of the yield strength on the dimensional accuracy at the time of punching and the peak half width of the (211) plane.

  As shown in FIG. 2, it has been found that in the case of a magnetic steel sheet having a yield strength of around 430 MPa, when the half-value width exceeds 0.16 °, the dimensional accuracy of the iron core varies greatly. On the other hand, in the electrical steel sheet having a yield strength of about 390 MPa, no large difference in dimensional accuracy was recognized depending on the half width. That is, the peak half width of the (211) plane in the X-ray diffraction is considered to be an index indicating the magnitude of the non-uniform strain applied to the magnetic steel sheet after the finish annealing.

  In the case of magnetic steel sheets with high yield strength, the load at the time of punching increases, but in the case of magnetic steel sheets with a large half-value width, the applied non-uniform strain is large, so the load change at the place where the mold hits is large. growing. Thus, it is considered that there is a possibility that a difference in dimensional accuracy at the time of punching may occur in an electromagnetic steel sheet having a high yield strength and a large half-value width.

  Therefore, in the present invention, the upper limit of the peak half width of the (211) plane in the X-ray diffraction profile of the magnetic steel sheet is set to 0.16 °. The peak half width of the (211) plane is desirably 0.15 ° or less, and more desirably 0.14 ° or less. Although the lower limit of the peak half width of the (211) plane is not particularly defined, the peak half width of the (211) plane can be obtained even when the magnetic steel sheet is subjected to strain relief annealing at 750 ° C. for 2 hours after finish annealing. Did not fall below 0.05 °. Therefore, the lower limit of the peak half width of the (211) plane may be, for example, 0.05 °.

  Further, the peak half width of the (211) plane in the X-ray diffraction profile of the magnetic steel sheet can be controlled by, for example, furnace tension or heat history of finish annealing. For example, the peak half-value width of the (211) plane of the magnetic steel sheet can be reduced by lowering the in-furnace tension and the cooling rate in the finish annealing.

  The conditions for punching the rotor core are as follows. The shape of the punched rotor core was the same as the rotor core of an 8-pole permanent magnet embedded motor, and was a disk shape with an outer diameter of 160 mm. The clearance of the punching die was 8% of the thickness of the magnetic steel sheet to be punched. After punching, the outer diameter of the punched rotor core is measured, and the maximum value of the difference between the target outer diameter 160 mm and the measured outer dimension is regarded as the outer diameter variation of the rotor core, and an index of dimensional accuracy. And

  As above, the electromagnetic steel sheet according to the present embodiment has been described in detail.

  The method for manufacturing the magnetic steel sheet according to the present embodiment is not particularly limited, and a general manufacturing process for a magnetic steel sheet can be applied. That is, the steel slab containing the components described above is hot-rolled, the hot-rolled sheet as it is after hot rolling, or hot-rolled, and then hot-rolled annealed hot-rolled sheet is cold-rolled, After performing the finish annealing, the electromagnetic steel sheet according to the present embodiment can be manufactured by applying the insulating coating. Note that the cold rolling may be performed by one cold rolling, or may be performed by two cold rollings sandwiching the intermediate annealing.

  Hereinafter, the electromagnetic steel sheet according to an embodiment of the present invention will be described more specifically with reference to experimental examples. The experimental examples described below are merely examples of the electromagnetic steel sheet according to the present embodiment, and the electromagnetic steel sheets according to the present embodiment are not limited to the experimental examples described below.

Here, the method for measuring the magnetic properties such as the magnetic flux density B ₅₀ and the iron loss W _10/800 shown below is not particularly limited. For example, a method based on the Epstein test specified in JIS C 2550 Or, a known method such as a single sheet tester (SST) specified in JIS C 2556 can be used. The magnetic flux density B ₅₀ is the magnetic flux density at a magnetization force of 5000 A / m, and the iron loss W _10/800 is the iron loss at a high frequency of 1.0 T and 800 Hz.

  In the following examples, the magnetic properties (for example, magnetic flux density and iron loss) of the magnetic steel sheet were evaluated by single-plate magnetic measurement (SST) using a test piece punched into a 55 mm square. In the motor core, magnetic flux flows in various directions on the plate surface of the electromagnetic steel sheet. Therefore, in order to evaluate the magnetic characteristics of the motor core, 0 °, 22.5 °, 45 °, 67. The magnetic characteristics in five directions of 5 ° and 90 ° were measured, and the average magnetic characteristics over the entire circumference were calculated by the following equation. That is, the better the magnetic properties represented by the following formulas, the better the non-oriented electrical steel sheet, and the more suitable it is as a motor core.

  Magnetic property = (0 ° property + 2 × 22.5 ° property + 2 × 45 ° property + 2 × 67.5 ° property + 90 ° property) / 8

(Experimental example 1)
A steel slab containing the composition shown in Table 1 below, the balance being Fe and impurities, was heated to 1150 ° C. and then hot-rolled to a thickness of 2.0 mm. Subsequently, the hot-rolled sheet was annealed at 1000 ° C. for 40 seconds, and then cold-rolled to a thickness of 0.25 mm. After soaking the cold-rolled sheet at 1000 ° C. for 1 second, finish annealing was performed at a cooling rate of 1 ° C./sec or 30 ° C./sec to 900 ° C. Furthermore, on both surfaces of the steel sheet after the finish annealing, a solution mainly containing a metal phosphate and containing an emulsion of an acrylic resin was applied and baked on both sides of the steel sheet to form a composite insulating film, thereby producing an electromagnetic steel sheet.

  For the finish annealing, a floating type continuous annealing furnace capable of running a steel sheet in a floating state by an in-furnace floater was used. In this experimental example, the peak half width in X-ray diffraction of the magnetic steel sheet was controlled by changing the cooling rate of the finish annealing. Since a steel sheet having a temperature of 900 ° C. or more has a low strength, a low cooling rate at which a temperature difference does not easily occur in the plane of the steel sheet is less likely to add distortion to the steel sheet, and a low peak half width in X-ray diffraction can be secured. . In order to achieve the peak half width of the magnetic steel sheet according to the present embodiment, the cooling rate of the finish annealing is desirably 20 ° C./sec or less, more desirably 15 ° C./sec or less.

  In Table 1, “Tr.” Indicates that the corresponding element was not added intentionally.

Thereafter, punching electromagnetic steel plates manufactured in 55mm square was evaluated flux density _{B 50} and the iron loss _{W 10/800} by veneer magnetic measurements (SST). In addition, regarding the evaluation of the dimensional accuracy, as described above, the manufactured electromagnetic steel sheet was punched into a rotor core shape having an outer diameter of 160 mm, and the outer diameter of the punched rotor core and the target outer diameter of 160 mm. The maximum value of the difference was determined as the outer diameter variation of the rotor core. The clearance of the punching die was set to 8% of the thickness of the magnetic steel sheet to be punched. When the outer diameter variation was 32 μm or less, the dimensional accuracy was evaluated as good (○), and when the outer diameter variation exceeded 32 μm, the dimensional accuracy was evaluated as poor (×). The results obtained are shown in Table 2 below.

  As shown in Table 2, the test numbers 1, 3, 6, 7, and 9 to 11 in which the composition, the peak half width, and the yield strength of the steel sheet are in the range of the present invention have excellent iron loss and magnetic flux density. It was found that the dimensional accuracy at the time of punching was good. On the other hand, even when the chemical composition of the steel sheet is within the range of the present invention, in Test Nos. 2 and 4, in which the peak half-value width of the (211) plane deviated from the range of the present invention, the magnetic flux density was excellent, The dimensional accuracy at the time was found to be inferior. In addition, it was found that in Test No. 5 in which the content of Si and the content of Si + Al + 0.5 × Mn of the steel sheet were lower than the range of the present invention and the yield strength was lower than the range of the present invention, the iron loss was inferior. Was.

(Experimental example 2)
A steel slab containing the composition shown in Table 3 below, the balance being Fe and impurities, was heated to 1100 ° C. and then hot-rolled to a thickness of 1.8 mm. Next, the hot-rolled sheet was annealed at 975 ° C. for 40 seconds, and then cold-rolled to a thickness of 0.20 mm. Subsequently, after the cold-rolled sheet was soaked at 950 ° C. for 80 seconds, finish annealing was performed at a cooling rate of 2 ° C./sec to 900 ° C. Furthermore, a solution mainly containing a metal phosphate and containing an emulsion of an acrylic resin was applied and baked on both sides of the steel sheet after finish annealing on both sides of the steel sheet to form a composite insulating film, thereby producing an electromagnetic steel sheet. Note that, for the finish annealing, the same floating type continuous annealing furnace as that in Experimental Example 1 was used.

  Experimental Example 2 is an experimental example in which the eddy current loss is small and the iron loss is small because the thickness of the electromagnetic steel sheet is smaller than that of Experimental Example 1. Referring to Experimental Example 2, it can be seen that the magnetic steel sheet according to one embodiment of the present invention can improve magnetic properties, mechanical strength, and dimensional accuracy at the time of punching, regardless of the sheet thickness.

  In Table 3, “Tr.” Means that the corresponding element was not added intentionally.

Thereafter, punching electromagnetic steel plates manufactured in 55mm square was evaluated flux density _{B 50} and the iron loss _{W 10/800} by veneer magnetic measurements in the same manner as in Experimental Example 1 (SST). Further, the electromagnetic steel sheet was stamped out in the same manner as in Experimental Example 1, and the dimensional accuracy was evaluated as in Experimental Example 1. The results obtained are shown in Table 4 below.

  As shown in Table 4, Test Nos. 13, 14 and 15, in which the composition, peak half width and yield strength of the steel sheet are within the scope of the present invention, are excellent in both iron loss and magnetic flux density, and have dimensional accuracy during punching. Was found to be good. On the other hand, in Test No. 12, in which the content of Si + Al + 0.5 × Mn was lower than the range of the present invention, it was found that iron loss was inferior.

As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that those skilled in the art to which the present invention pertains can conceive various changes or modifications within the scope of the technical idea described in the claims. It is understood that these also belong to the technical scope of the present invention.

Claims (2)

In mass%, C: 0.005% or less, Si: 3.0% or more and 4.0% or less, Mn: 3.0% or less, S: 0.004% or less, sol. Al: 0.1% or more and 1.5% or less, P: 0.03% or more and 0.15% or less, the balance being Fe and impurities,
3.5% ≦ Si + sol. Al + 0.5 × Mn ≦ 5.0%,
The yield strength is 400 MPa or more;
An electromagnetic steel sheet, wherein the peak half width of the (211) plane in the X-ray diffraction profile measured on the steel sheet surface is 0.16 ° or less. In mass%, C: 0.005% or less, Si: 3.0% or more and 4.0% or less, Mn: 3.0% or less, S: 0.004% or less, sol. Al: 0.1% to 1.5%, P: 0.03% to 0.15%, Sn: 0.001% to 0.15%, the balance being Fe and impurities,
3.5% ≦ Si + Al + 0.5 × Mn ≦ 5.0%,
The yield strength is 400 MPa or more;
An electromagnetic steel sheet, wherein the peak half width of the (211) plane in the X-ray diffraction profile measured on the steel sheet surface is 0.16 ° or less.

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