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    • 专利摘要:
    grain oriented electric steel sheet and method for fabrication thereof. The present invention relates to a grain oriented electric steel sheet where the thickness of forsterite film in bottom portions of the grooves formed on a steel sheet surface is <243> 0.3 <109> m, the frequency groove <242> 20% which is a crystal grain abundance ratio of grooves directly below them, each crystal grain having an orientation that deviates from the goss orientation by (243) 10º and grain size <243> 5 <109> m, total stress by tension coating is <243> 10.0 mpa, the total stress exerted on the steel sheet in the direction perpendicular to the direction of rolling by the forsterite film and stress coating is <243> 5.0 mpa and total stresses satisfy 1.0 <242> a / b <242> 5.0 where a is the total stress exerted in the direction of rolling by the forsterite film and stress coating, and b is the total stress exerted in the direction perpendicular to the direction of lamination by the forster film and by the stress coating.
    公开号:BR112013002008B1
    申请号:R112013002008-3
    申请日:2011-08-05
    公开日:2019-07-02
    发明作者:Takeshi Omura；Hirotaka Inoue；Hiroi Yamaguchi；Seiji Okabe
    申请人:Jfe Steel Corporation；
    IPC主号:
    专利说明:

    Descriptive Report of the Invention Patent for ELECTRIC STEEL SHEET ORIENTED BY GRAIN AND METHOD FOR MANUFACTURING THE SAME.
    TECHNICAL FIELD [001] The present invention relates to a grain-oriented electric steel sheet used for iron core materials such as transformers and a method for making it.
    BACKGROUND OF THE TECHNIQUE [002] Electric grain-oriented steel sheets, which are mainly used as iron cores for transformers, are required to have excellent magnetic properties, in particular less iron loss.
    [003] To satisfy this requirement, it is important that the secondary recrystallized grains are highly aligned on the steel sheet in the (110) orientation [001] (or the so-called Goss orientation) and the impurities in the steel product sheet are reduced . However, there are limitations to controlling crystal orientation and reducing impurities in terms of balance with maintenance cost and so on. Therefore, some techniques were developed to introduce non-uniform deformation on the surfaces of a steel sheet in a physical way and to reduce the magnetic domain width for less iron loss, that is, magnetic domain refining techniques.
    [004] For example, the document No. JP 57-002252 B (PTL 1) proposes a technique for reducing iron loss of a steel sheet by irradiating a final steel sheet product with a laser, which introduces a region high displacement density in the surface layer of the steel sheet and reduces the magnetic domain width. Furthermore, the document No. JP 62-053579 B (PTL 2) proposes a technique for refining magnetic domains by forming grooves having a
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    2/42 depth of more than 5 pm in the base iron portion of a steel sheet after final annealing at a load of 882 to 2156 MPa (90 to 220 kgf / mm 2 ) and then submit the sheet steel to heat treatment at a temperature of 750 ° C or higher. Furthermore, the document JP No. 7-268474 A (PTL 3) discloses a technique to provide a steel sheet having linear grooves extending in a direction almost orthogonal to the direction of lamination of the steel sheet in a bottom surface iron and also has continuous grain contours or fine grain regions of 1 mm or less grain size from the bottom of the linear grooves to the other surface on the base iron in the direction of sheet thickness. With the development of the techniques described above for magnetic domain refining, grain-oriented electric steel sheets that have good iron loss properties can be obtained.
    PATENT DOCUMENTS
    PTL 1: JP 57-002252 B PTL 2: JP 62-053579 B PTL 3: JP 7-268474 A
    SUMMARY OF THE INVENTION (Technical Problem) [005] However, the aforementioned techniques for performing magnetic domain refining treatment by forming grooves have a lesser effect in reducing iron loss compared to other magnetic domain refining techniques to introduce high displacement density regions by laser irradiation and so on. The aforementioned techniques also have a problem that there is little improvement in the iron loss of an assembled real transformer, even if the iron loss is reduced through magnetic domain refining. That is, these techniques provide an extremely unsatisfactory construction factor (BF).
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    3/42 (Solution to the Problem) [006] The present invention was developed in these circumstances. An objective of the present invention is to provide a grain-oriented electric steel sheet that can further reduce the loss of iron from a material with grooves formed in it for refining the magnetic domain and exhibit excellent low iron loss properties when assembled as a real transformer, along with an advantageous method for making the same.
    That is, the provision of the present invention is summarized as follows:
    [1] A grain-oriented electric steel sheet comprising: a forsterite film and tensile coating on a steel sheet surface; and grooves for refining the magnetic domain on the surface of the steel sheet, where a thickness of the forsterite film in the bottom portions of the grooves is 0.3 pm or more, where a groove frequency is 20% or less , the groove frequency is a ratio of the groove abundance, each groove has grains directly below it, each grain has an orientation that deviates from the Goss orientation by 10 ° or more and a grain size of 5 pm or more , and where a total pull exerted on the steel sheet in a rolling direction by the forsterite film and the pull coating is 10.0 MPa or more, a total pull exerted on the steel sheet in a direction perpendicular to the direction of lamination by the forsterite film and the tensile coating is 5.0 MPa or more and these total stresses satisfy a ratio:
    1.0 <A / B <5.0, where
    A is total traction exerted in the rolling direction by the
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    4/42 forsterite film and traction coating, and
    B is a total traction exerted in the direction perpendicular to the lamination direction by the forsterite film and the traction coating.
    [2] A method for making a grain-oriented electric steel sheet, the method comprising: subjecting a plate to a grain-oriented electric steel sheet to the lamination to be finished to a final sheet thickness; subject the sheet to subsequent decarburization; then apply an annealing separator composed mainly of MgO to a surface of the sheet before subjecting the sheet to final annealing; and subjecting the sheet to the subsequent tensile coating, in which (1) groove formation for the magnetic domain refining is carried out before final annealing to form a forsterite film, (2) the annealing separator has an amount of coating of 10.0 g / m 2 or more, (3) the winding traction after the application of the annealing separator is controlled within a range of 30 to 150 N / mm 2 , (4) an average cooling rate of 700 ° C during a final annealing cooling step is controlled to be 50 ° C / hour or less, (5) during final annealing, the atmospheric gas flow rate over a temperature range of at least 900 ° C or highest is controlled to be 1.5 Nm 3 / hour * tonne or less, and (6) an end point temperature during final annealing is controlled to be 1,150 ° C or higher.
    [3] The method for making a grain-oriented electric steel sheet according to item [2] above, in which the plate for the grain-oriented electric steel sheet is subjected to hot rolling and optionally to the coil annealing. the hot and
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    5/42 subsequently subjected to cold rolling once, or twice or more with intermediate annealing performed between them, to be finished in a final sheet thickness.
    (Advantageous Effect of the Invention) [008] According to the present invention, since the iron loss reduction effect of a steel sheet, which has grooves formed in it and is subjected to magnetic domain refining treatment, also it must be maintained in a real transformer effectively and such a grain-oriented electric steel sheet can be obtained and that demonstrates excellent low iron loss properties in a real transformer.
    BRIEF DESCRIPTION OF THE DRAWINGS [009] The present invention will be further described below with reference to the accompanying drawings, in which:
    [0010] Figure 1 is a cross-sectional view of a groove portion of a steel sheet formed in accordance with the present invention; and [0011] Figure 2 is a cross-sectional view of a sheet of steel taken in a direction orthogonal to the groove portions. DESCRIPTION OF THE MODALITIES [0012] The present invention will be described specifically below. In the present invention, in order to improve the iron loss properties of a grain-oriented electric steel sheet as a material with grooves formed in it for the magnetic domain refining and which has a forsterite film (a film composed mainly Mg2SiO4) and to prevent deterioration in the construction factor in a real transformer using this grain-oriented electric steel sheet, the thickness of the forsterite film formed in the bottom portions of the grooves, the traction exerted on the steel sheet and the grains directly below the grooves are defined as follows.
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    6/42 [0013] The thickness of the forsterite film in the bottom portions of the grooves: 0.3 pm or more [0014] The effect achieved by introducing the grooves through magnetic domain refining to form grooves is less than effect obtained by the magnetic domain refining technique to introduce a high displacement density region, since a smaller magnetic charge is introduced. First, an investigation was conducted on the magnetic loading introduced when the grooves were formed. As a result, a correlation was found between the thickness of the forsterite film in which the grooves were formed and the magnetic loading. Thus, further investigations were conducted on the relationship between film thickness and magnetic loading. As a result, it has been shown that increasing the thickness of the film in which the grooves were formed is effective in increasing magnetic loading.
    [0015] Consequently, the thickness of the forsterite film that is needed to increase magnetic loading and to enhance the magnetic domain refining effect is 0.3 pm or more, preferably 0.6 pm or more.
    [0016] On the other hand, the upper limit of the thickness of the forsterite film is preferably about 5.0 pm, since the adhesion with the steel sheet deteriorates and the forsterite film ends more easily if the forsterite film is very thick.
    [0017] Although the cause of an increase in magnetic charge as described above has not been clarified exactly, the inventors of the present invention believe in the following. That is, there is a correlation between the thickness of the film and the traction exerted on the steel sheet by the film, in which the traction exerted by the film on the bottom portions of the grooves becomes greater with increasing film thickness. This increased traction is believed to have caused an increase in
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    7/42 internal stress of the steel sheet in the bottom portions of the grooves, which resulted in an increase in magnetic loading.
    [0018] When the loss of iron from a grain-oriented electric steel sheet is evaluated as a product, the magnetization flow only contains the directional rolling components and, therefore, it is only necessary to increase the traction in the rolling direction to improve the loss of iron. However, when a grain-oriented electric steel sheet is assembled like a real transformer, the magnetization flow contains not only the directional rolling elements, but also the components with transversal direction. Consequently, traction in the rolling direction as well as traction in the transversal direction have an influence on the loss of iron.
    [0019] Therefore, in the present invention, it is considered that an optimal tensile ratio is defined by a ratio of the directional rolling components to the components with transversal direction of the magnetization flow. Specifically, an optimal traction ratio is considered to satisfy Formula (1) below:
    1.0 <A / B <5.0 ..... (1), preferably, 1.0 <A / B <3.0, where A is a total pull exerted in the lamination direction by the forsterite film and by the traction coating, and
    B is a total pull exerted in the transverse direction by the forsterite film and the pull liner.
    [0020] Furthermore, even if the condition described above is satisfied, degradation in the loss of iron is inevitable when the absolute value of the traction exerted on the steel sheet is small. In view of the aforementioned, as a result of further investigations in the preferred values of traction in the rolling direction and in the transversal direction, it was revealed that in the transversal direction, a total traction
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    8/42 exerted by the forsterite film and the traction coating it is considered that it is sufficient if it is 5.0 MPa or more, where in the rolling direction, a total traction exerted by the forsterite film and the coating tensile strength should be 10.0 MPa or more. It should be noted that there is no particular upper limit on the total tensile A in the rolling direction as long as the steel sheet will not deform plastically. A preferred upper limit of total traction A is 200 MPa or less.
    [0021] In the present invention, the total traction exerted by the forsterite film and the traction coating is defined as follows. [0022] When the tensile in the rolling direction is measured, a sample of 280 mm in the rolling direction x 30 mm in the transversal direction is cut from the product (material applied as traction coating), in which when the tensile in the direction cross section is measured, a sample of 280 mm in the cross direction x 30 mm in the rolling direction is cut from the product. Then, the forsterite film and the traction liner on one side are removed. Then, the sheet steel warp is determined by measuring the warp before and after removal and converted to traction using the conversion formula (2) provided below. The traction defined by this method represents the traction that is exerted on the surface from which the forsterite film and the traction coating have not been removed. Since traction is exerted on both sides of the sample, two samples were prepared to measure the same product in the same direction and traction was defined for each side by the method described above to derive an average value for traction. This average value is considered as the traction that is exerted in the sample.
    [Conversion formula (2)] σ = 2 (to 2 -a,)
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    9/42 where, σ: film pull (MPa)
    E: Young modulus of steel sheet = 143 (GPa) l: measurement length of warp (mm) ai: warp before removal (mm) a2: warp after removal (mm) d: thickness of steel sheet ( mm) [0023] In the present invention, the thickness of the forsterite film in the bottom portions of the grooves is calculated as follows.
    [0024] As illustrated in Figure 1, the forsterite film present in the bottom portions of the grooves was observed with SEM in a cross section taken along the direction in which the grooves extend, in which the area of the forsterite film was calculated by image analysis and the calculated area was divided by a measuring distance to determine the thickness of the forsterite film of the steel sheet. In this case, the measuring distance was 100 mm.
    Groove frequency: 20% or less [0025] According to the present invention, a groove frequency is important to be a ratio of the groove abundance, each groove has grains directly below it, each grain has an orientation that deflects the from Goss orientation by 10 ° or more and a grain size of 5 pm or more. According to the present invention, it is important that this groove frequency is 20% or less.
    [0026] Next, the groove frequency will be explained specifically.
    [0027] To improve the construction factor, it is important to define the tensile strength of the forsterite film as described above, as well as to leave as few grains that deviate as much from the Goss orientation as possible directly below the portions in which the grooves are formed.
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    10/42 [0028] It should be noted that in this situation of PTL 2 and PTL 3 that the loss of iron from the material improves more in that the fine grains are present directly below the grooves. However, when the actual transformers were manufactured by the inventors of the present invention using two types of materials, one with fine grains present directly below the grooves and the other without fine grains directly below the grooves, the previous material provided better results from than the previous one due to the fact that the real transformer exhibited better iron loss, that is, the construction factor was better, although lower in the iron loss of the material.
    [0029] In view of this, additional investigations were conducted on materials with fine grains present directly below the grooves formed in them. As a result, it was found that the value of a groove frequency, is a ratio of those grooves with grains present directly below them to the grooves without grains directly below them, is important. Each material has a groove frequency of 20% or less and I show a good construction factor, although the specific groove frequency calculation will be described later. Therefore, the groove frequency of the present invention should be 20% or less.
    [0030] As described above, although the reason why the iron loss results of a material and the iron loss results of a real transformer does not always show a consistent trend that has not been clarified, the inventors of the present invention believe that this would be attributed to a difference between a form of magnetization flux from the actual transformer and a form of magnetization flux where for use in material evaluation. Consequently, although fine grains directly below the grooves have an effect on improving the loss of iron from the material, it is necessary to reduce such fine grains directly below the grooves as much
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    11/42 as possible considering the use in real transformers since they would otherwise cause an adverse effect of the deterioration in the construction factor. However, ultrafine grains sized less than 5 pm, as well as fine grains sized 5 pm or more but which has a good crystal orientation that deviates from the Goss orientation by less than 10 °, has no adverse effects nor positive and therefore there is no problem if these grains are present.
    [0031] Consequently, as used in this document, a fine grain is defined as a grain that has an orientation that deviates from the direction of Goss by 10 ° or more, that has a grain size of 5 pm or more and that is subjected to groove frequency derivation. In addition, the upper limit of the grain size is about 300 pm. In view of this, if the grain size exceeds this limit, the loss of iron from the material deteriorates and therefore lowers the frequency of the grooves that have fine grains in some way does not have much effect in improving the loss of iron in a real transformer. [0032] In the present invention, the grain size of grains present directly below the grooves, the difference in crystal orientation and the groove frequency are determined as follows.
    [0033] As shown in Figure 2, the grain size of the grains is determined as follows: a cross section is observed at 100 points in a direction perpendicular to the groove portions and if there is a grain, the grain size of it is calculated as an equivalent circle diameter. In addition, the difference in crystal orientation is defined as an angle of deviation from the Goss orientation through the use of EBSP (electron backscatter standard) to measure the crystal orientation of the crystals in the bottom portions of the grooves. In addition, the groove frequency means a ratio of the number of grooves in the presence of grains as specified by
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    12/42 present invention at the 100 measuring points described above divided by the number of measuring points, 100.
    [0034] In the following, the conditions for manufacturing a grain-oriented electric steel sheet according to the present invention will be specifically described below.
    [0035] In the present invention, a plate for a grain-oriented electric steel sheet can have any chemical composition that allows secondary recrystallization. In addition, the higher the degree of grain alignment in the <100> direction, the greater the effect of reducing iron loss obtained through magnetic domain refining. It is therefore preferred that a magnetic flux density B8, which provides an indication of the degree of grain alignment, is 1.90 T or higher. [0036] In addition, if an inhibitor, for example, an AlN-based inhibitor is used, Al and N may be contained in an appropriate amount, respectively, although if an MnS / MnSe-based inhibitor is used, Mn and Whether and / or S can be contained in an appropriate amount, respectively. It is obvious, that these inhibitors can also be used in combination. In this case, the preferred contents of Al, N, S and Se are: Al: 0.01 to 0.065% by weight; N: 0.005 to 0.012% by weight; S: 0.005 to 0.03% by weight; and If: 0.005 to 0.03% by weight, respectively.
    [0037] Furthermore, the present invention is also applicable to a grain-oriented electric steel sheet that has limited contents of Al, N, S and Se without the use of an inhibitor.
    [0038] In this case, the amounts of Al, N, S and Se are preferably limited to: Al: 100 ppm of mass or less: N: 50 ppm of mass or less; S: 50 ppm of mass or less; and If: 50 ppm of mass or less, respectively.
    [0039] The basic elements and other elements optionally added from the plate to an electric steel sheet oriented by
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    13/42 grain of the present invention will be described specifically below.
    <C: 0.08% by weight or less>
    [0040] C is added to enhance the texture of a hot-rolled sheet. However, the C content that exceeds 0.08% by weight increases the burden of reducing the C content to 50 ppm by weight or less where magnetic aging will not occur during the manufacturing process. Therefore, the C content is preferably 0.08% by weight or less. In addition, it is not necessary to establish a particular lower limit for the content of C since secondary recrystallization is permitted by a material that does not contain C.
    <Si: 2.0 to 8.0% by mass>
    [0041] Si is an element that is useful to increase the electrical resistance of steel and improve iron loss. The Si content of 2.0 wt% or more has a particularly good effect in reducing iron loss. On the other hand, the Si content of 8.0% by weight or less can offer particularly good formability and density of magnetic flux. Therefore, Si content is preferably within the range of 2.0 to 8.0% by mass.
    <Mn: 0.005 to 1.0% by mass>
    [0042] Mn is an element that is advantageous for improving hot formability. However, the Mn content less than 0.005% by mass has a less addition effect. On the other hand, the Mn content of 1.0 mass% or less provides a particularly good magnetic flux density for the product sheet. Therefore, the Mn content is preferably within the range of 0.005 to 1.0% by mass.
    [0043] In addition, in addition to the above elements, the plate can also contain the following elements as elements to enhance the magnetic properties:
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    14/42 at least one element selected from: Ni: from 0.03 to 1.50% by weight; Sn: from 0.01 to 1.50% by weight; Sb: from 0.005 to 1.50% by mass; Cu: from 0.03 to 3.0% by weight; P: from 0.03 to 0.50% by weight; Mo: from 0.005 to 0.10% by weight; and Cr: from 0.03 to 1.50% by weight.
    [0044] Ni is an element that is useful to further improve the texture of a hot-rolled sheet to obtain additionally improved magnetic properties. However, Ni content of less than 0.03 wt% is less effective in providing magnetic properties, where Ni content of 1.50 wt% or less increases, in particular, the stability of secondary recrystallization and provides further improved magnetic properties. Therefore, the Ni content is preferably within the range of 0.03 to 1.50% by weight.
    [0045] Sn, Sb, Cu, P, Mo and Cr are useful elements for the further improvement of magnetic properties, respectively. However, if any of these elements are contained in an amount less than the lower limit described above, it is less effective in improving the magnetic properties, and if contained in an amount equal to or less than its upper limit as described above, it provides the best growth of the secondary recrystallized grains. Therefore, each of these elements is preferably contained in an amount within the range described above.
    [0046] The balance other than that of the elements described above is Fe and accidental impurities that are incorporated during the manufacturing process.
    [0047] Then, the plate that has the chemical composition described above is subjected to heating before hot rolling in a conventional manner. However, the plate can also be subjected to
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    15/42 hot rolling directly after casting, without being subjected to heating. In the case of a thin plate, it can be subjected to hot lamination or sent to the next step, which omits hot lamination.
    [0048] In addition, the hot-rolled sheet is optionally subjected to the annealing of the hot-rolled coil. A main purpose of hot coil annealing is to improve the magnetic properties by dissolving the strip texture generated by hot rolling to obtain a primary recrystallization texture of the uniformly sized grains and, in this way, further develops the texture of Goss during secondary recrystallization annealing. At this time, in order to obtain a highly developed Goss texture on a product sheet, a hot coil annealing temperature is preferably in the range of 800 ° C to 1,100 ° C. If an annealing temperature of the hot coil is less than 800 ° C, a band texture that results from hot rolling remains, which makes it difficult to obtain a primary recrystallization texture of the uniformly sized grains and prevents a desired improvement in recrystallization. secondary. On the other hand, if a hot coil annealing temperature exceeds 1,100 ° C, the grain size after hot coil annealing becomes very rough, making it difficult to obtain a primary recrystallization texture from the uniformly sized grains .
    [0049] After annealing the hot coil, the sheet is subjected to cold lamination once, or twice or more with intermediate annealing performed between them, followed by decarburization (combined with recrystallization annealing) and application of a annealing separator on the sheet. After the application of the annealing separator, the sheet is subjected to the final annealing
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    16/42 for secondary recrystallization purposes and forming a forsterite film. It should be realized that the annealing separator is preferably composed mainly of MgO in order to form forsterite. As used herein, the term mainly MgO compound implies that any well-known compound for the annealing separator and any property improvement compound other than MgO can also be contained within a range without interfering with the formation of a forsterite film intended by the invention. Furthermore, as described later, the groove formation according to the present invention is carried out at any stage after the final cold rolling and before the final annealing.
    [0050] After the final annealing, it is effective to subject the sheet to the flattening annealing to correct the shape of the same. In accordance with the present invention, the insulating coating is applied to the surfaces of the steel sheet before or after the flattening annealing. As used herein, this insulation coating means that such a coating can apply tensile strength to the steel sheet to reduce iron loss (hereinafter referred to as tensile coating). The traction coating includes an inorganic coating that contains silica and ceramic coating by physical vapor deposition, chemical vapor deposition and so on.
    [0051] In the present invention, it is important to properly adjust the tension to be exerted on the steel sheet in the rolling direction and in the transversal direction. In this case, the traction in the rolling direction can be controlled by adjusting the amount of traction coating to be applied. That is, the pull coating is often performed in a cooking furnace in which a steel sheet is applied with a coating liquid and baked, although it is stretched
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    17/42 in the lamination direction. Consequently, in the rolling direction, the steel sheet is fired with a coating material although it is stretched and thermally expanded.
    [0052] When the steel sheet is discharged and cooled after cooking, it will shrink more than the coating material due to the shrinkage caused by the discharge and the difference in the thermal expansion coefficient between the steel sheet and the material of cladding, which leads to a condition where the cladding material maintains a traction on the steel sheet and thereby applies traction to the steel sheet.
    [0053] On the other hand, in the transverse direction, the steel sheet will not be stretched in the baking furnace, but instead it will be stretched in the rolling direction, which leads to a condition in which the steel sheet is compressed in the direction transversal. Consequently, such compression compensates for the elongation of the steel sheet due to thermal expansion. Therefore, it is difficult to increase the traction to be applied in the transverse direction by the traction coating. [0054] In view of the above, the following control items are provided in the present invention for manufacturing conditions to improve the traction of the forsterite film in the transverse direction.
    That is, (a) the annealing separator has a coating amount of 10.0 g / m 2 or more, (b) the winding pull after the application of the annealing separator is controlled within a range of 30 to 150 N / mm 2 , (c) an average cooling rate at 700 ° C during the final annealing cooling step is controlled to be 50 ° C / hour or less.
    [0055] Since the steel sheet is subjected to final annealing in coiled form, there are greater temperature variations during the
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    18/42 cooling. As a result, the amount of thermal expansion in the steel sheet is likely to vary with location. Consequently, stress is exerted on the steel sheet in several directions. That is, when the steel sheet is wound tightly, great stress is exerted on the steel sheet as it exists in the gap between the adjacent loop surfaces of the steel sheet and would damage the film. [0056] Consequently, what is effective in preventing damage to the film is to reduce the stress generated on the steel sheet by leaving some gaps between the surfaces of the adjacent turns of the steel sheet and to decrease the cooling rate and thereby reduces temperature variations in the coil.
    [0057] Below in this document, reference will be made to the mechanism for reducing damage to the film by controlling the items listed above (a) to (c).
    [0058] Since an annealing separator releases moisture or CO2 during annealing, which shows a decrease in volume over time after application. It will be appreciated that a decrease in volume indicates the occurrence of gaps due to the fact that the portion is effective for stress relaxation. In that case, if the annealing separator has a small amount of coating, this will result in insufficient spans. Therefore, the amount of coating on the annealing separator should be limited to 10.0 g / m 2 or more. In addition, there is no particular upper limit on the amount of coating on the annealing separator without interfering with the manufacturing process (such as causing the coil to interlace during the final annealing). If any inconvenience such as that described above entanglement is generated, it is preferred that the amount of coating is 50 g / m 2 or less.
    [0059] In addition, as the winding traction is reduced, more gaps are created between the adjacent loop surfaces of the sheet
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    19/42 steel than in the case where the steel sheet is wound with a higher tensile strength. This results in less stress generated. However, an excessively low winding traction also has a problem, due to the fact that it would cause the winding to unwind. Consequently, the winding traction is defined as being within a range of 30 to 150 N / mm 2 as a condition in which any stress caused by temperature variations during cooling can be relaxed and unwinding will not occur. [0060] Furthermore, if the cooling rate during the final annealing is decreased, the temperature variations will be reduced in the steel sheet and therefore the stress on the coil is relaxed. A slower cooling rate is better from the point of view of stress relaxation, but less favorable in terms of production efficiency. It is therefore preferred that the cooling rate is 5 ° C / hour or higher. In the present invention, due to a combination of controlling the amount of coating of the annealing separator and controlling the winding traction, a cooling rate of up to 50 ° C / hour is acceptable as an upper limit.
    [0061] In this way, stress is relaxed by controlling each amount of coating on the annealing separator, a winding traction and the cooling rate. As a result, it is possible to improve the traction of the forsterite film in the transverse direction.
    In the present invention, it is important to form the forsterite film in the bottom portions of the grooves with a thickness above a certain level. In order to form the forsterite film in the bottom portions of the grooves, it is necessary to form grooves before forming the forsterite film for the following reason.
    [0062] That is, if the forsterite film is formed before the grooves are formed through the use of pressing means such as gear cylinders, then deformation will be introduced
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    20/42 unnecessary on the surfaces of the steel sheet. This requires annealing at a high temperature to remove the deformation introduced by pressing after the formation of grooves. When such high temperature annealing is performed, fine grains are formed directly below the grooves. However, it is extremely difficult to control the crystal orientation of such fine grains, which causes the iron loss properties of a real transformer to deteriorate. In such a case, additional annealing such as final annealing can be carried out at elevated temperature and over a long period of time to eliminate the fine grains described above. However, such an additional process leads to reduced productivity and an increase in cost.
    [0063] Furthermore, if the final annealing is performed and the forsterite film is formed before the grooves are formed by chemical polishing such as electrolysis notch, then the forsterite film will be removed during chemical polishing. Consequently, the forsterite film needs to be formed again in order to satisfy the amount of the forsterite film in the bottom portions of the grooves, which also leads to an increased cost.
    [0064] To form the forsterite film in the bottom portions of the grooves with a predefined thickness, it is important that during the final annealing, the flow rate of atmospheric gas in a temperature range of at least 900 ° C or higher is controlled to be of
    1.5 Nm 3 / hour * tonne or less. Bearing in mind that the atmospheric circulation capacity will be very high in the groove portions in comparison to the interlayer portions other than the groove portions since large gaps are left in the groove portions until the steel sheet is wound tightly.
    [0065] However, an excessively high atmospheric circulation capacity causes difficulty for gas such as oxygen which
    Petition 870190036943, of 17/04/2019, p. 23/52
    21/42 is released from the annealing separator during the final annealing to be retained between the interlayer portions. This causes a reduction in the amount of additional oxidation of the steel sheet during final annealing, which results in a disadvantage that the forsterite film becomes thinner. It should be noted that the capacity for atmospheric circulation is low in the interlayered portions other than the bottom portions, whose interlayered portions are therefore less susceptible to the rate of atmospheric gas flow. Therefore, there is no problem if the atmospheric gas flow rate is limited as described above. Although there is no particular limit on the lower limit of the atmospheric gas flow rate, in general, the lower limit of the atmospheric gas flow rate is 0.01 Nm 3 / hour * tonne or more.
    [0066] In the present invention, grooves are formed on a grain-oriented electrical steel sheet surface at any stage after the cold rolling described above and before final annealing. In this case, by controlling the thickness of the forsterite film in the bottom portions of the grooves and the groove frequency and controls the total traction of the forsterite film and the traction coating in the lamination direction and the transverse direction as described above, a improvement in iron loss is most effectively achieved by means of a magnetic domain refining effect obtained by the formation of grooves and a sufficient magnetic domain refining effect is obtained.
    [0067] In this case, during the final annealing, a size effect provides a driving force for secondary recrystallization such as primary recrystallized grains are invaded by the secondary recrystallized grains. However, if the primary recrystallization becomes rough due to normal grain growth, the difference in grain size between the secondary recrystallized grains and the primary recrystallized grains is reduced. Consequently, the effect
    Petition 870190036943, of 17/04/2019, p. 24/52
    22/42 in size is reduced so that the primary recrystallized grains become less prone to invasion and some primary recrystallized grains remain as they are. The resulting grains are fine grains with unsatisfactory crystal orientation. Any deformation introduced at the periphery of the grooves during the formation of the grooves makes the primary recrystallized grains prone to becoming rough and thus the fine grains remain more often. To decrease the frequency of occurrence of fine grains with unsatisfactory crystal orientation as well as the frequency of occurrence of the grooves with such fine grains, it is necessary to control an end point temperature during final annealing of 1,150 ° C or higher.
    [0068] Furthermore, by controlling the end point temperature to be 1,150 ° C or higher to increase the actuation force for the growth of secondary recrystallized grains, invasion of rough primary recrystallized grains is allowed regardless of the presence or absence deformation at the periphery of the grooves.
    [0069] In addition, if the deformation formation is carried out by a chemical scheme such as electrolysis notch without introducing deformation, through a mechanical scheme using cylinders with protuberances or the like, then the asperization of primary recrystallized grains can be suppressed and the frequency of occurrence of residual fine grains can be reduced in an efficient manner.
    [0070] Depending on the groove formation, a chemical scheme such as electrolysis notch is more preferable.
    [0071] It is desirable that the shape of each groove in the present invention is in linear form, although it is not limited to a particular shape while the magnetic domain width can be reduced. [0072] Grooves are formed through different methods including conventionally well-known methods for forming
    Petition 870190036943, of 17/04/2019, p. 25/52
    23/42 grooves, for example, a local engraving method, tracing method through the use of cutters or the like, laminating method that uses bulky cylinders and so on. The most preferred method is a method including adhesion, by printing or the like, etching resistance on a sheet of steel after being subjected to final cold rolling and then forming grooves in a region of non-adhesion of the sheet through of a process such as electrolysis notching.
    [0073] According to the present invention, in the case of linear grooves being formed on a surface of the steel sheet, it is preferable that each groove has a width of about 50 to 300 pm, a depth of about 10 to 50 pm and a groove interval of about 1.5 to 10.0 mm and that each linear groove deviates from a direction perpendicular to the rolling direction within a range of ± 30 °. As used in this document, linear is intended to encompass the solid line as well as the dotted line, the dashed line and so on.
    [0074] In accordance with the present invention, with the exception of the aforementioned manufacturing steps and conditions, a conventionally well-known method for making a grain-oriented electric steel sheet can be applied in which the magnetic domain refining treatment is performed by forming grooves. EXAMPLES [Example 1] [0075] The steel plates, each having the chemical composition as shown in Table 1, were manufactured by continuous casting. Each of these steel plates was heated to 1400 ° C, subjected to hot rolling to be finished on a hot rolled sheet that has a sheet thickness of 2.2 mm and then subjected to the hot coil annealing at 1020 ° C by 180
    Petition 870190036943, of 17/04/2019, p. 26/52
    24/42 seconds. Subsequently, each steel sheet was subjected to cold rolling to an intermediate sheet thickness of 0.55 mm and then to intermediate annealing under the following conditions: degree of oxidation PH2O / PH2 = 0.25, temperature = 1050 ° C and duration = 90 seconds. Subsequently, each steel sheet was blasted with hydrochloric acid to remove the subcrostrates from its surfaces, followed by cold rolling again to be finished on a cold rolled sheet that has a sheet thickness of 0.23 mm .
    [Table 11
    Identification ofsteel Chemical composition [mass%] (C, O, N, Al, Se and S: [pmmass] Ç Si Mn Ni O N Al If s THE 450 3.25 0.04 0.01 16 70 230 tr 20 B 550 3.30 0.11 0.01 15 25 30 100 30 Ç 700 3.20 0.09 0.01 12 80 200 90 30 D 250 3.05 0.04 0.01 25 40 60 tr 20
    _Equilibrium: Fe and accidental impurities_ [0076] Therefore, each sheet of steel was applied with engraving resistance through offset printing by notch. Then, each steel sheet was subjected to electrolysis and resistance gutting in an alkaline solution, and through this, the linear grooves, each 150 pm wide and 20 pm deep, are formed at 3 mm intervals at a 10 ° tilt angle to a direction perpendicular to the rolling direction.
    [0077] Thus, each steel sheet was subjected to decarburization in which it was retained in a degree of oxidation of PH2O / PH2 = 0.55 and a waterlogging temperature of 825 ° C for 200 seconds. Then, an annealing separator composed mainly of MgO was applied to each steel sheet. In that
    Petition 870190036943, of 17/04/2019, p. 27/52
    At the time, the amount of annealing separator applied and the winding pull after application of the annealing separator were varied as shown in Table 2. Therefore, each steel sheet was subjected to final annealing for the purposes of secondary recrystallization and of purification under conditions of 1250 ° C and 10 hours in a mixed atmosphere of N2: H2 = 60:40.
    [0078] In this final annealing, the end point temperature was controlled to be 1,200 ° C, where the gas flow rate at 900 ° C or higher and the average rate of cooling during a cooling process in a range temperature of 700 ° C or higher have been changed. In addition, each steel sheet was subjected to flat annealing to correct the shape of the steel sheet, where it was held at 830 ° C for 30 seconds. Then, the traction coating composed of 50% colloidal silica and magnesium phosphate was applied to each steel sheet to be finished in a product, in which the magnetic properties and the film traction were evaluated. It should be noted that this traction in the rolling direction has been adjusted by changing the amount of applied traction coating. In addition, other products were also produced as comparative examples in which the grooves were formed by the method mentioned above after the final annealing. In this case, the manufacturing conditions except the moment of groove formation were the same as described above. Then, each product was sheared into pieces of material that has a beveled edge to be mounted in a three-phase transformer at 500 kVA and then measured for its iron loss in a situation where it was excited at 50 Hz and 1.7 T.
    [0079] The measurement results mentioned above for iron loss are shown in Table 2.
    Petition 870190036943, of 17/04/2019, p. 28/52 [Table 2]
    No. Steel identification Groove formation moment Amount separator annealing applied (g / m 2 ) inin T ration after applied annealing winding Rate ofcoolingup to 700 ° C (° C / h) Gas flow rate at 900 ° C or more (Nm 3 / h.ton) Thickness of the forsterite film in the bottom portions of the grooves (pm) separate separator (N / mm 2 ) into be 1 After cold rolling 13 25 25 0.8 - 2 After cold rolling 7 50 30 1.0 0.5 3 After cold rolling 11 50 30 1.0 0.5 4 THE After cold rolling 11 50 30 2.6 0.1 5 After Final Annealing 11 50 30 1.0 0 6 After cold rolling 11 50 30 1.0 0.5 7 After cold rolling 13 50 30 1.0 0.5 8 After cold rolling 12 80 100 0.8 0.7 9 After cold rolling 12 80 60 0.8 0.7 10 After cold rolling 12 80 40 0.8 0.7 11 After cold rolling 12 80 40 0.8 0.7 12 B After Final Annealing 12 80 40 0.8 0 13 After cold rolling 12 80 40 1.8 0.2 14 After cold rolling 12 80 20 0.8 0.7 15 After cold rolling 12 170 20 0.8 0.7 16 After cold rolling 6 80 20 0.8 0.7
    26/42
    Petition 870190036943, of 17/04/2019, p. 29/52 [Table 2] -continuation-
    No. Steel identification Groove formation moment Amount of annealing separator applied (g / m 2 ) Winding traction after the annealing separator is applied (N / mm 2 ) Rate ofcoolingup to 700 ° C (° C / h) Gas flow rate at 900 ° C or more (Nm 3 / h.ton) Thickness of the forsterite film in the bottom portions of the grooves (pm) 17 After cold rolling 15 120 3 0.6 0.8 18 After cold rolling 15 120 45 0.6 0.8 19 Ç After cold rolling 15 120 45 2.1 0.15 20 After cold rolling 15 120 45 0.6 0.8 21 After cold rolling 15 200 45 0.6 0.8 22 After cold rolling 15 200 80 0.6 0.8 23 After cold rolling 12 60 30 0.3 1.2 24 After cold rolling 12 60 30 0.7 0.9 25 D After Final Annealing 12 170 30 0.7 0 26 After cold rolling 12 170 30 2.1 0.15 27 After cold rolling 8 250 30 0.5 0.9 28 After cold rolling 8 300 100 0.5 0.9
    27/42
    Petition 870190036943, of 17/04/2019, p. 30/52 [Table 2] -continuation-
    No. Steel identification Groove formation moment Frequencygroove (%) Traction applied to the steel sheet Traction in rolling direction (MPa) Traction in the transverse direction (MPa) Lamination direction / transverse direction 1 After cold rolling - - - - 2 After cold rolling 0 15 2.7 5.6 3 After cold rolling 0 15 7.5 2.0 4 THE After cold rolling 0 15 7.5 2.0 5 After Final Annealing 0 15 7.5 2.0 6 After cold rolling 0 9 8.0 1.1 7 After cold rolling 0 15 6.2 2.4 8 After cold rolling 0 16 1.7 9.4 9 After cold rolling 0 16 2.5 6.4 10 After cold rolling 0 7 8.0 0.9 11 After cold rolling 0 18 8.0 2.3 12 B After Final Annealing 0 16 6.0 2.7 13 After cold rolling 0 16 6.0 2.7 14 After cold rolling 0 16 6.0 2.7 15 After cold rolling 0 16 2.8 5.7 16 After cold rolling 0 12 2.5 4.8 17 After cold rolling 0 16 6.5 2.5 18 Ç After cold rolling 0 16 6.5 2.5 19 After cold rolling 0 16 6.5 2.5
    28/42
    Petition 870190036943, of 17/04/2019, p. 31/52 [Table 2] -continuation-
    At the Steel identification Groove formation moment Frequencygroove (%) Traction applied to the steel sheet Traction in rolling direction (MPa) Traction in the transverse direction (MPa) Lamination direction / transverse direction 20 After cold rolling 0 35 6.5 5.4 21 After cold rolling 0 18 3.0 6.0 22 After cold rolling 0 18 1.8 10.0 23 After cold rolling 0 20 6.5 3.1 24 After cold rolling 0 20 6.8 2.9 25 Pi After Final Annealing 0 20 4.2 4.8 26 D After cold rolling 0 20 4.2 4.8 27 After cold rolling 0 20 1.8 11.1 28 After cold rolling 0 20 1.2 16.7
    29/42 [Table 2] -continuation-
    At the Steel identification Groove formation moment W17 / 50 (W / kg) Product W17 / 50 (W / kg) transformer Construction factor Others comments 1 After cold rolling - - - Unwinding occurred, not available as a product Examplecomparative 2 After cold rolling 0.69 0.94 1.36 - Examplecomparative 3 THE After cold rolling 0.69 0.83 1.20 - Innovative example 4 After cold rolling 0.72 0.87 1.21 - Examplecomparative 5 After Final Annealing 0.73 0.88 1.21 - Examplecomparative
    Petition 870190036943, of 17/04/2019, p. 32/52 [Table 2] -continuation-
    No. Steel identification Groove formation moment W17 / 50 (W / kg) Product W17 / 50 (W / kg) transformer Factorconstruction Others Comment 6 After cold rolling 0.75 0.91 1.21 - Comparative example 7 After cold rolling 0.69 0.83 1.20 - Innovative example 8 B After cold rolling 0.67 0.94 1.40 - Comparative example 9 After cold rolling 0.67 0.95 1.42 - Comparative example 10 After cold rolling 0.73 1.01 1.38 - Comparative example 11 After cold rolling 0.67 0.82 1.22 - Innovative example 12 After Final Annealing 0.72 0.87 1.21 - Comparative example 13 After cold rolling 0.71 0.86 1.21 - Comparative example 14 After cold rolling 0.67 0.82 1.22 - Innovative example 15 After cold rolling 0.67 0.95 1.42 - Comparative example 16 After cold rolling 0.72 0.96 1.33 - Comparative example 17 Ç After cold rolling 0.65 0.79 1.22 (productivitylow) Innovative example 18 After cold rolling 0.65 0.79 1.22 - Innovative example 19 After cold rolling 0.69 0.83 1.20 - Comparative example 20 After cold rolling 0.62 0.87 1.40 - Comparative example 21 After cold rolling 0.65 0.94 1.45 - Comparative example 22 After cold rolling 0.65 0.97 1.49 - Comparative example
    30/42
    Petition 870190036943, of 17/04/2019, p. 33/52 [Table 2] -continuation-
    At the Steel identification Groove formation moment W17 / 50 (W / kg) -product W17 / 50 (W / kg) transformer Factorconstruction Others comments 23 D After cold rolling 0.65 0.79 1.22 - Innovative example 24 After cold rolling 0.66 0.80 1.21 - Innovative example 25 After Final Annealing 0.71 0.93 1.31 - Examplecomparative 26 After cold rolling 0.70 0.92 1.31 - Examplecomparative 27 After cold rolling 0.66 0.95 1.44 - Examplecomparative 28 After cold rolling 0.66 1.03 1.56 - Examplecomparative
    31/42
    Petition 870190036943, of 17/04/2019, p. 34/52
    32/42 [0080] As shown in Table 2, when using a grain-oriented electric steel sheet that is subjected to magnetic domain refining treatment by forming grooves so that it has a traction within the scope of present invention, deterioration in the building factor is inhibited and an extremely good iron loss property is obtained. However, when using a grain-oriented electric steel sheet that departs from the scope of the present invention, the same failure to provide low iron loss and deterioration in the building factor is observed as a real transformer until the sheet steel display good loss of iron from the material.
    [Example 2] [0081] Steel plates that have chemical compositions shown in Table 1 were subjected to the same procedure under the same conditions as in Experiment 1 until the cold rolling stage. Therefore, a surface of each steel sheet was pressed locally with protruding cylinders so that linear grooves, each 150 pm wide and 20 pm deep, were formed at 3 mm intervals at a 10 ° tilt angle. with respect to a direction perpendicular to the rolling direction. Then, each sheet of steel was subjected to decarbonisation in which it was retained in a PH2O / PH2 oxidation degree of 0.50 and the soaking temperature of 840 ° C for 300 seconds. Then, an annealing separator composed mainly of MgO was applied to each steel sheet. At that time, the amount of the annealing separator applied and the winding traction after the application of the annealing separator were varied as shown in the Table
    3. Therefore, each steel sheet was subjected to final annealing for the purposes of secondary recrystallization and purification under conditions of 1230 ° C and 100 hours in a mixed atmosphere of Ν2Ή2 = 30:70.
    Petition 870190036943, of 17/04/2019, p. 35/52
    33/42 [0082] In this final annealing, the gas flow rate at 900 ° C or higher, the average rate of cooling during a cooling process over a temperature range of 700 ° C or higher and point temperature end have been changed. In addition, each steel sheet was subjected to flat annealing to correct the shape of the steel sheet, where it was held at 820 ° C for 100 seconds. Then, the traction coating composed of 50% colloidal silica and magnesium phosphate was applied to each steel sheet to be finished in a product, in which the magnetic properties and film traction were evaluated. It should be noted that the traction in the rolling direction has been adjusted by changing the amount of applied traction coating. In addition, other products were also produced as comparative examples in which the grooves were formed by the method mentioned above after the final annealing. In this case, the manufacturing conditions except the moment of groove formation were the same as described above. Then, each product was sheared into pieces of material with a beveled edge to be mounted in a three-phase transformer at 500 kVA and then measured for its iron loss in a situation where it was excited at 50 Hz and 1.7 T.
    [0083] The measurement results mentioned above for iron loss are shown in Table 3.
    Petition 870190036943, of 17/04/2019, p. 36/52 [Table 3]
    At the, Identifying thesteel Groove formation moment Amount of annealing separator applied (g / m 2 ) Winding traction after the annealing separator is applied (N / mm 2 ) Cooling rate at 700 ° C (° C / h) Gas flow rate at 900 ° C or (Nm 3 / h.ton) more 1 After cold rolling 14 15 20 0.7 2 After cold rolling 6 55 35 1.0 3 After cold rolling 12 55 35 1.0 4 Λ After cold rolling 12 55 35 1.0 5 After cold rolling 12 55 35 2.4 6 After Final Annealing 12 55 35 1.0 7 After cold rolling 12 55 35 1.0 8 After cold rolling 14 55 35 1.0 9 After cold rolling 13 85 110 0.7 10 After cold rolling 13 85 70 0.7 11 After cold rolling 13 85 45 0.7 12 After cold rolling 13 85 45 0.7 13 D After cold rolling 13 85 45 0.7 14 B After Final Annealing 13 85 45 0.7 15 After cold rolling 13 85 45 1.7 16 After cold rolling 13 85 25 0.7 17 After cold rolling 13 175 25 0.7 18 After cold rolling 5 85 25 0.7
    34/42
    Petition 870190036943, of 17/04/2019, p. 37/52 [Table 3] -continuation-
    At the, Identifying thesteel Groove formation moment Amount of annealing separator applied (g / m 2 ) Winding traction after the annealing separator is applied (N / mm 2 ) Cooling rate at 700 ° C (° C / h) Gas flow rate at 900 ° C or (Nm 3 / h.ton) more 19 After cold rolling 16 115 2 0.6 20 After cold rolling 16 115 40 0.6 21 After cold rolling 16 115 40 0.6 22 P After cold rolling 16 115 40 1.9 23 After Final Annealing 16 115 40 0.6 24 After cold rolling 16 115 40 0.6 25 After cold rolling 16 190 40 0.6 26 After cold rolling 16 190 80 0.6 27 After cold rolling 13 65 25 0.3 28 After cold rolling 13 65 25 0.5 29 After cold rolling 13 65 25 0.5 30 D After Final Annealing 13 165 25 0.5 31 After cold rolling 13 165 25 1.9 32 After cold rolling 7 260 25 0.5 33 After cold rolling 7 320 95 0.5
    35/42
    Petition 870190036943, of 17/04/2019, p. 38/52 [Table 3] -continuation-
    At the, Identification ofsteel Groove formation moment Spot temperatureend after thefinal annealing (° C) Film thicknessforsterite in the portionsgroove background(pm) Frequencygroove (%) Traction applied to the sheetof steel Traction in the direction oflamination (MPa) 12345678 THE After cold rolling 1,180 - - - After cold rolling 1,180 0.5 15 14 After cold rolling 1,180 0.5 15 14 After cold rolling 1120 0.5 60 14 After cold rolling 1,180 0.1 15 14 After Final Annealing 1,180 0.5 80 14 After cold rolling 1,180 0.5 15 8 After cold rolling 1,180 0.5 15 14
    36/42
    Petition 870190036943, of 17/04/2019, p. 39/52 [Table 3] -continuation-
    At the, Identificationsteel of Groove formation moment Spot temperatureend after thefinal annealing (° C) Film thickness Frequencygroove (%) Traction applied to the sheetof steel forsteritebackground(pm) in the portionsfrom the grooves Traction in the direction oflamination (MPa) 9 After cold rolling 1,200 0.7 10 15 10 After cold rolling 1,200 0.7 10 15 11 After cold rolling 1,200 0.7 10 6 12 After cold rolling 1,200 0.7 10 17 13 After cold rolling 1,140 0.7 30 15 14 B After Final Annealing 1,200 0.7 45 15 15 After cold rolling 1,200 0.2 10 15 16 After cold rolling 1,200 0.7 10 15 17 After cold rolling 1,200 0.7 10 15 18 After cold rolling 1,200 0.7 10 12
    Petition 870190036943, of 17/04/2019, p. 40/52 [Table 3] -continuation-
    At the, Identification of Groove formation moment End point temperature after final annealing (° C) Thickness of the forsterite film in the bottom portions of the grooves (pm) Groove frequency (%) Traction applied to the steel sheet steel Traction in rolling direction (MPa) 19 After cold rolling 1,170 0.8 0 15 20 After cold rolling 1,170 0.8 0 15 21 After cold rolling 1,130 0.8 25 15 22 Ç After cold rolling 1,170 0.15 0 15 23 After Final Annealing 1,170 0.8 30 15 24 After cold rolling 1,170 0.8 0 30 25 After cold rolling 1,170 0.8 0 17 26 After cold rolling 1,170 0.8 0 19 27 After cold rolling 1,200 1.2 10 21 28 After cold rolling 1,200 0.9 10 21 29 After cold rolling 1,130 0.9 40 21 30 D After Final Annealing 1,200 0.9 60 21 31 After cold rolling 1,200 0.15 12 21 32 After cold rolling 1,200 0.9 12 21 33 After cold rolling 1,200 0.9 12 21
    38/42
    Petition 870190036943, of 17/04/2019, p. 41/52 [Table 3] -continuation-
    At the Steel identification Timeformationgroove givesof Traction in the transverse direction (MPa) Lamination direction / transverse direction W17 / 50(W / kg) product W17 / 50(W / kg) transformador Construction factor Others comments 1 Afterlaminationcold TheThe - - - - - Unwinding occurred, not available as a product Examplecomparative 2 Afterlaminationcold TheThe 2.5 5.6 0.67 0.93 1.39 - Examplecomparative 3 Afterlaminationcold TheThe 7.3 1.9 0.67 0.81 1.21 - Innovative example 4 THE Afterlaminationcold TheThe 7.3 1.9 0.65 0.85 1.31 - Examplecomparative 5 Afterlaminationcold TheThe 7.3 1.9 0.70 0.85 1.21 - Examplecomparative 6 after theannealingFinal 7.3 1.9 0.65 0.84 1.29 - Examplecomparative 7 Afterlaminationcold TheThe 7.5 1.1 0.73 0.89 1.22 - Examplecomparative 8 Afterlaminationcold TheThe 6.3 2.2 0.67 0.81 1.21 - Innovative example
    39/42
    Petition 870190036943, of 17/04/2019, p. 42/52 [Table 3] -continuation-
    At the, Steel identification Groove formation moment Traction ontransverse direction (MPa) Direction oflamination / directiontransversal W17 / 50(W / kg) product W17 / 50(W / kg) -transformedor Factorconstruction Others comments 9 After cold rolling 1.8 8.3 0.69 0.96 1.39 - Comparative example 10 After cold rolling 2.7 5.6 0.69 0.97 1.41 - Comparative example 11 After cold rolling 8.0 0.8 0.75 1.03 1.37 - Comparative example 12 After cold rolling 8.0 2.1 0.69 0.84 1.22 - Innovative example 13 B After cold rolling 8.0 1.9 0.68 0.89 1.31 - Comparative example 14 After Final Annealing 6.5 2.3 0.68 0.88 1.29 - Comparative example 15 After cold rolling 6.5 2.3 0.73 0.88 1.21 - Comparative example 16 After cold rolling 6.0 2.5 0.69 0.84 1.22 - Innovative example 17 After cold rolling 3.0 5.0 0.69 0.97 1.41 - Comparative example 18 After cold rolling 2.5 4.8 0.74 0.98 1.32 - Comparative example
    40/42
    Petition 870190036943, of 17/04/2019, p. 43/52 [Table 3] -continuation-
    At the, Steel identification Groove formation moment Traction ontransverse direction (MPa) Direction oflamination / directiontransversal W17 / 50(W / kg) Product W17 / 50(W / kg) Transformador Factorinconstruction Others comments 19 After cold rolling 6.0 2.5 0.66 0.80 1.21 (low productivity) Innovative example 20 After cold rolling 6.0 2.5 0.66 0.80 1.21 - Innovative example 21 After cold rolling 6.0 2.5 0.65 0.84 1.29 - Comparative example 22 Ç After cold rolling 6.0 2.5 0.70 0.84 1.20 - Comparative example 23 After Final Annealing 6.0 2.5 0.65 0.84 1.29 - Comparative example 24 After cold rolling 6.0 5.0 0.63 0.88 1.40 - Comparative example 25 After cold rolling 2.2 7.7 0.66 0.95 1.44 - Comparative example 26 After cold rolling 1.2 15.8 0.66 0.98 1.48 - Comparative example 27 After cold rolling 6.5 3.2 0.66 0.79 1.20 - Innovative example 28 After cold rolling 6.5 3.2 0.67 0.80 1.19 - Innovative example 29 After cold rolling 6.5 3.2 0.65 0.85 1.31 - Comparative example 30 D After Final Annealing 6.5 3.2 0.65 0.84 1.29 - Comparative example 31 After cold rolling 4.5 4.7 0.71 0.92 1.30 - Comparative example 32 After cold rolling 1.8 11.7 0.67 0.95 1.42 - Comparative example 33 After cold rolling 1.2 17.5 0.67 1.03 1.54 - Comparative example
    41/42
    Petition 870190036943, of 17/04/2019, p. 44/52
    42/42 [0084] As shown in Table 3, each grain-oriented electric steel sheet is subjected to magnetic domain refining treatment by forming grooves so that it has a traction within the scope of the present invention less susceptible to deterioration in its construction factor and offers extremely good iron loss properties. In contrast, each grain-oriented electric steel sheet that departs from the scope of the present invention fails to provide low iron loss properties and deteriorates in its construction factor like a real transformer, even if it exhibits iron loss properties. good as a material.
    权利要求:
    Claims (3)
    [1]
    claims
    1. Grain-oriented electric steel sheet, characterized by the fact that it comprises: a forsterite film and tensile coating on a steel sheet surface; and grooves for refining the magnetic domain on the surface of the steel sheet, where a thickness of the forsterite film in the bottom portions of the grooves is 0.3 pm to 0.5 pm, where the upper limit of the grain size which has an orientation that deviates from the Goss direction by 10 ° or more is 300 pm, where a groove frequency is 20% or less, the groove frequency is a ratio of groove abundance, each groove having grains directly below it, each grain having an orientation that deviates from the Goss orientation by 10 ° or more and a grain size of 5 pm or more, and in which a total pull exerted on the steel sheet in a rolling direction by forsterite film and tensile coating is 10.0 MPa or more, a total tensile strength exerted on the steel sheet in a direction perpendicular to the rolling direction by the forsterite film and tensile coating is 5.0 MPa or more , and these total tensions satisfy a relationship:
    1.0 <A / B <5.0, where
    A is total traction exerted in the lamination direction by the forsterite film and the traction coating, and
    B is a total traction exerted in the direction perpendicular to the lamination direction by the forsterite film and the traction coating.
    [2]
    2. Method for making a grain-oriented electric steel sheet, as defined in claim 1, the method characterized by the fact that it comprises: submitting a plate to a sheet of steel
    Petition 870190036943, of 17/04/2019, p. 46/52
    2/2 grain-oriented electric to the lamination to be finished in a final sheet thickness; subject the sheet to subsequent decarburization; then apply an annealing separator composed mainly of MgO to a surface of the sheet before subjecting the sheet to final annealing; and subjecting the sheet to the subsequent tensile coating, in which (1) groove formation for the magnetic domain refining is carried out before final annealing to form a forsterite film, (2) the annealing separator has an amount of coating of 10.0 g / m 2 or more, (3) the winding traction after the application of the annealing separator is controlled within a range of 30 to 150 N / mm 2 , (4) an average cooling rate of 700 ° C during the final annealing cooling step is controlled to be 50 ° C / hour or less, (5) during the final annealing, the atmospheric gas flow rate over a temperature range of at least 900 ° C or highest is controlled to be 1.5 Nm 3 / hour * tonne or less, and (6) an end point temperature during final annealing is controlled to be 1,150 ° C or higher.
    [3]
    3. Method for manufacturing a grain-oriented electric steel sheet, according to claim 2, characterized in that the plate for the grain-oriented electric steel sheet is subjected to hot rolling and optionally annealing the coil to hot and subsequently subjected to cold lamination once, or twice or more with the intermediate annealing performed between them, to be finished in a final sheet thickness.
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    JP2012036446A|2012-02-23|
    WO2012017690A1|2012-02-09|
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    法律状态:
    2019-01-22| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|
    2019-05-07| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2019-07-02| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 05/08/2011, OBSERVADAS AS CONDICOES LEGAIS. (CO) 20 (VINTE) ANOS CONTADOS A PARTIR DE 05/08/2011, OBSERVADAS AS CONDICOES LEGAIS |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2010178026A|JP5853352B2|2010-08-06|2010-08-06|Oriented electrical steel sheet and manufacturing method thereof|
    JP2010-178026|2010-08-06|
    PCT/JP2011/004473|WO2012017690A1|2010-08-06|2011-08-05|Directional magnetic steel plate and production method therefor|
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