JP4277529B2 - Method for producing grain-oriented electrical steel sheet having no undercoat - Google Patents

Description

【００４１】
実施例２
Ｃ：0.0030mass％、Si：3.2mass％、Al：25ppmおよびMn：0.05mass％を含有し、Ｎ：15ppm、Ｓ：５ppmであって、Seが20、30、40、50ppmの４水準であり、その他成分を合計で10ppm以下に低減した組成の鋼スラブを連続鋳造にて製造した。ついで、スラブを1200℃に加熱後、粗圧延出側温度を表２に示す種々の温度に調整して熱間圧延を行って2.5mm厚に仕上げた。その後、Ｎ₂雰囲気中で900℃で１分間均熱した後急冷した。
【００４２】
次に、冷間圧延により0.35mmの最終板厚とした後、水素50vol％および窒素50vol％、露点-10℃の雰囲気中で900℃で10秒の再結晶焼鈍を行った。その後、露点-20℃以下の窒素雰囲気中にて、常温〜875℃までを50℃／ｈの速度で昇温し、その温度で50時間保持する条件に従って、最終仕上焼鈍を行った。
【００４３】
かくして得られた製品板の鉄損と磁束密度を測定した。その結果を、表２に併記するように、Se：10ppmでは粗圧延出側温度：900℃以上で、Se：20ppm、30ppmおよび40ppmでは同950℃以上で、Ｂ₈：1.83Ｔ以上の良好な磁気特性が得られた。
【００４４】
【表２】

【００４５】
実施例３
Ｃ：0.0030mass％、Si：3.2mass％、Mn：0.05mass％およびＮ：15ppm含有し、Ｓ：５ppm、Se：10ppmであって、Alが20、50、80ppmの３水準であり、その他成分を合計で10ppm以下に低減した組成の鋼スラブを連続鋳造にて製造した。ついで、スラブを1200℃に加熱後、粗圧延出側温度を表３に示す種々の温度に調整して熱間圧延を行って2.5mm厚に仕上げた。その後、Ｎ₂雰囲気中で900℃で１分間均熱した後急冷した。
【００４６】
次に、冷間圧延により0.35mmの最終板厚とした後、水素50vol％および窒素50vol％、露点-10℃の雰囲気中で900℃で10秒の再結晶焼鈍を行った。その後、露点-20℃以下の窒素雰囲気中にて、常温〜875℃までを50℃／ｈの速度で昇温し、その温度で50時間保持する条件に従って、最終仕上焼鈍を行った。
【００４７】
かくして得られた製品板の鉄損と磁束密度を測定した。その結果を、表３に併記するように、Al：20ppmでは粗圧延出側温度：900℃以上で、Al：50ppmでは同950℃以上で、そしてAl：80ppmでは同1000℃以上で、Ｂ₈：1.83Ｔ以上の良好な磁気特性が得られた。
【００４８】
【表３】

【００４９】
【発明の効果】
本発明によれば、フォルステライト（Mg₂SiO₄）を主体とする下地被膜（グラス被膜）を有しないため打ち抜き加工性に優れ、しかもコイル長さ方向に安定した磁気特性を有する方向性電磁鋼板を提供することができる。
【図面の簡単な説明】
【図１】 ＥＩ型コアの形状を示す図である。
【図２】 不純物Ｓ量と熱間圧延時の粗圧延出側温度を変えた場合のＢ₈を示す図である。
【図３】 不純物Se量と熱間圧延時の粗圧延出側温度を変えた場合のＢ₈を示す図である。
【図４】 不純物Al量と熱間圧延時の粗圧延出側温度を変えた場合のＢ₈を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a grain-oriented electrical steel sheet used mainly for iron core materials of small motors and generators.
[0002]
[Prior art]
For example, in a small transformer, electromagnetic steel plates are laminated and used as a core. As a typical shape of this core, an EI type core as shown in FIG. 1 (a) or (b) is known. Although this EI type core is manufactured by punching, an efficient processing method as shown in FIG. 5C is used, which generates a small amount of scrap when punching.
[0003]
Currently, both non-oriented electrical steel sheets and directional electrical steel sheets are used for the core material for the EI type core. First, when a non-oriented electrical steel sheet is used, the magnetic properties of the core are inferior because the level of magnetic properties is lower than when a directional electrical steel sheet is used. However, non-oriented electrical steel sheet since it is kept low to simple price manufacturing process as compared to the directional electric magnetic steel sheet, it has been used from an economic point of view.
[0004]
On the other hand, grain-oriented electrical steel sheets have good magnetic properties in the rolling direction, but extremely poor magnetic properties in the direction perpendicular to the rolling direction. However, about 20% of the flow of magnetic flux in the EI core flows in the direction perpendicular to the rolling direction, but about 80% is in the rolling direction, so when a grain-oriented electrical steel sheet is used as the iron core material of the EI type core. Provides much better properties than non-oriented electrical steel sheets. For this reason, grain oriented electrical steel sheets are often used in many cases where iron loss is important.
[0005]
Here, the EI type core is manufactured by punching a steel plate with a die. Usually, the surface of the grain-oriented electrical steel sheet is provided with a base film (glass film) mainly composed of forsterite (Mg ₂ SiO ₄ ). Compared to the coating, the forsterite coating is remarkably hard, so the wear of the punching die is great. For this reason, it is necessary to re-grind or replace the mold, resulting in a reduction in work efficiency and an increase in cost at the time of iron core processing by the customer. Similarly, the slit property and the cut property are deteriorated by the presence of the forsterite film.
[0006]
As a method of improving the punchability of grain-oriented electrical steel sheets, it is common to remove the forsterite film by pickling or grinding, but this not only increases the cost, but also deteriorates the surface properties and magnetism. There is a big problem that the characteristics deteriorate.
[0007]
On the other hand, Patent Document 1 and Patent Document 2 include a technique for suppressing the formation of a forsterite film by blending a chemical in an annealing separator mainly composed of MgO applied at the time of finish annealing. Technologies for applying an annealing separator mainly composed of silica and alumina to a material containing Mn have been proposed.
[0008]
In these methods, forsterite is often formed partially due to fluctuations in the finish annealing atmosphere between the layers of the coil, and it has been extremely difficult to obtain a product plate in which the formation of forsterite is completely suppressed.
[0009]
In contrast, the inventors proposed a technique in Patent Document 4 that uses a high-purity material that does not contain an inhibitor component to develop secondary recrystallization using the effect of suppressing the grain boundary migration of solute nitrogen. did. In this technique, it is not necessary to purify the inhibitor component at a high temperature. Therefore, finish annealing can be performed without using an annealing separator, and a steel plate without a forsterite film can be obtained.
[0010]
Furthermore, Patent Document 5 proposes a technique for further suppressing the formation of an oxide film by making the atmosphere in recrystallization annealing low-oxidation using a component with reduced C. With these technologies, grain oriented electrical steel sheets that do not form forsterite can be manufactured at low cost. And the grain-oriented electrical steel sheet which does not have a hard forsterite film on such a surface is advantageously adapted to a small electric device such as an EI core that emphasizes punching workability.
[0011]
[Patent Document 1]
Japanese Patent Publication No. 6-49948 [Patent Document 2]
Japanese Patent Publication No. 6-49949 [Patent Document 3]
JP-A-8-134542 [Patent Document 4]
JP 2000-129356 [Patent Document 5]
Japanese Patent Laid-Open No. 2001-32021
[Problems to be solved by the invention]
However, it has been found that the electromagnetic characteristics vary in the longitudinal direction of the coil of the final product while the inventors repeatedly manufacture with the above technique.
[0013]
Therefore, the present invention intends to provide a grain-oriented electrical steel sheet having uniform electromagnetic characteristics by giving a way to suppress variation in magnetic characteristics in an electrical steel sheet without a forsterite coating.
[0014]
[Means for Solving the Problems]
Now, when the cause was investigated about the dispersion | variation in the electromagnetic characteristic in the coil longitudinal direction of a final product, when the trace element which produces Mn compounds like S and Se, for example was comparatively many, it turned out that dispersion | variation is large. That is, when these impurities are large, the impurities once re-dissolved by slab reheating start reprecipitation at a low temperature portion during hot rolling, and the precipitate grows Ostwald coarsely, In the subsequent recrystallization annealing process, the recrystallization in the coil becomes non-uniform, and as a result, the electromagnetic characteristics of the final product are considered to vary.
[0015]
Here, the slab, which is the material of the grain-oriented electrical steel sheet, is generally subjected to hot rolling after being reheated in a gas furnace using combustion gas as a fuel. The rough rolling outlet temperature or finish rolling outlet temperature of hot rolling is usually uniquely determined by the steel type.
[0016]
Accordingly, the inventors diligently studied how to solve the above problems, and controlling the hot rolling rough rolling outlet temperature in accordance with the content of impurities in the molten steel solved the above problems. It came to know that it was very effective to do.
Hereinafter, experiments that have made the present invention successful will be described.
[0017]
C: 0.0030mass%, Si: 3.2mass% and Mn: 0.05mass%, Al is 30ppm, N is 15ppm, S is 5, 10, 20, 30, 40ppm, and other components are total A steel slab having a composition reduced to 10 ppm or less was produced by continuous casting. Next, the slab was heated to 1200 ° C., and the rough rolling outlet temperature was adjusted to various temperatures within the range of 850 to 1100 ° C. to perform hot rolling to finish 2.5 mm. Thereafter, it was soaked at 900 ° C. for 1 minute in an N ₂ atmosphere and then rapidly cooled.
[0018]
Next, after a final sheet thickness of 0.35 mm was obtained by cold rolling, recrystallization annealing was performed at 900 ° C. for 10 seconds in an atmosphere of 50 vol% hydrogen, 50 vol% nitrogen, and dew point of −10 ° C. Thereafter, in a nitrogen atmosphere with a dew point of −20 ° C. or lower, the temperature was raised from room temperature to 875 ° C. at a rate of 50 ° C./h, and final finish annealing was performed according to the condition of holding at that temperature for 50 hours.
[0019]
The iron loss and magnetic flux density of the product plate thus obtained were measured. As a result, as shown in FIG. 2, as the content of S, which is a trace element, increases, good electromagnetic characteristics cannot be obtained when the rough rolling exit temperature is low.
The reason is considered as follows.
[0020]
That is, S contained in the steel is precipitated as a sulfide like MnS in the slab state. By heating this slab, the sulfide dissolves, but by applying a strain like rough rolling, the strained portion becomes the core of precipitation. The reprecipitation of sulfide starts when the temperature decreases during rolling, but the reprecipitation starts at a higher temperature as the amount of impurities increases. In the part where precipitation began during rough rolling, the Ostwald growth of the precipitate occurs before finish rolling, resulting in non-uniform recrystallization in the coil longitudinal direction in the subsequent steps, and uniform and good electromagnetic properties in the final product. It is thought that was not obtained.
[0021]
Similar to S, the same examination was performed on Se which forms an Mn compound.
That is, C: 0.0030 mass%, Si: 3.2 mass%, Mn: 0.05 mass%, Al: 25 ppm, and N 15 ppm, S: 5 ppm, Se is each level of 20, 30, 40, 50 ppm A steel slab having a composition with other components reduced to 10 ppm or less in total was produced by continuous casting. Next, the slab was heated to 1200 ° C., and the rough rolling outlet temperature was adjusted to various temperatures within the range of 850 to 1100 ° C. to perform hot rolling to finish 2.5 mm. Thereafter, it was soaked at 900 ° C. for 1 minute in an N ₂ atmosphere and then rapidly cooled.
[0022]
Next, after a final sheet thickness of 0.35 mm was obtained by cold rolling, recrystallization annealing was performed at 900 ° C. for 10 seconds in an atmosphere of 50 vol% hydrogen, 50 vol% nitrogen, and dew point of −10 ° C. Thereafter, in a nitrogen atmosphere having a dew point of −20 ° C. or lower, the temperature was raised from room temperature to 875 ° C. at a rate of 50 ° C./h, and final finish annealing was performed according to the condition of holding at that temperature for 50 hours.
[0023]
The iron loss and magnetic flux density of the product plate thus obtained were measured. As shown in FIG. 3, as in the case of S, the results show that as the content of Se as a trace element increases, good electromagnetic characteristics cannot be obtained when the rough rolling exit temperature is low.
The reason for this is also considered as described above.
[0024]
Furthermore, C: 0.0030mass%, Si: 3.2mass%, Mn: 0.05mass% and N 15ppm, S: 5ppm, Se: 10ppm, Al is each level of 20, 50, 80ppm, other components Steel slabs with a composition reduced to 10 ppm or less in total were produced by continuous casting. Next, the slab was heated to 1200 ° C., and the rough rolling outlet temperature was adjusted to various temperatures within the range of 850 to 1100 ° C. to perform hot rolling to finish 2.5 mm. Thereafter, it was soaked at 900 ° C. for 1 minute in an N ₂ atmosphere and then rapidly cooled.
[0025]
Next, after a final sheet thickness of 0.35 mm was obtained by cold rolling, recrystallization annealing was performed at 900 ° C. for 10 seconds in an atmosphere of 50 vol% hydrogen, 50 vol% nitrogen, and dew point of −10 ° C. Thereafter, in a nitrogen atmosphere having a dew point of −20 ° C. or lower, the temperature was raised from room temperature to 875 ° C. at a rate of 50 ° C./h, and final finish annealing was performed according to the condition of holding at that temperature for 50 hours.
[0026]
The iron loss and magnetic flux density of the product plate thus obtained were measured. As shown in FIG. 4, the results show that, as in the case of S and Se, as the content of Al as a trace element increases, good electromagnetic characteristics cannot be obtained when the rough rolling exit temperature is low. It was.
The reason for this is also considered as described above.
[0027]
From the above experiments, it has been found that good magnetic properties can be obtained by controlling the rough rolling exit temperature in accordance with the content of impurity elements in the steel.
And, including these experiments, when the relationship between the rough rolling outlet temperature and the impurity elements in the steel was intensively investigated, the rough rolling outlet temperature T (° C.) was calculated as T ≧ 3.14 × [S (ppm)] +1.28 × [Se (ppm)] + 1.14 × [Al (ppm)] + 842
It has been found that it is desirable to control so as to obtain good electromagnetic characteristics. That is, from various experiments including the above-mentioned experiment, it has been clarified that, among impurities in steel, S, Se, and Al have a strong influence on the minimum required rough rolling exit temperature, and the content and coarseness of these elements We investigated the correlation with the rolling exit temperature and derived the previous equation.
[0028]
In order to eliminate the influence of the impurity element, it is effective to remove the impurity element itself, but this increases the refining cost and inevitably contains the element, which is not practical.
[0029]
Based on the above experiments, the inventors have newly found that good magnetic properties can be stably obtained, and completed the present invention.
That is, the gist configuration of the present invention is as follows.
(1) C: 0.08 mass% or less, Si: 2.0-8.0 mass% and Mn: 0.005-3.0 mass%, sol. A slab produced using molten steel consisting of Fe and unavoidable impurities, with Al reduced to 100 ppm or less and N reduced to 50 ppm or less, and S and Se reduced to 50 ppm or less, respectively, and then 1 After performing cold rolling at least twice with intermediate or intermediate annealing, perform recrystallization annealing in an atmosphere with a dew point of 40 ° C or lower, and then perform final finish annealing in an atmosphere with a dew point of 40 ° C or lower. When producing a grain-oriented electrical steel sheet having no undercoat mainly composed of forsterite (Mg ₂ SiO ₄ ), the hot rolling rough rolling outlet temperature T ( ° C.) determines the target value of the method of Do we have ways oriented electrical steel sheet having a base film and controlling the hot rolling so as to satisfy the target value.
Serial T ≧ 3.14 × [S (ppm )] + 1.28 × [Se (ppm)] + 1.14 × [Al (ppm)] + 842
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Next, the reasons for limitation of each component of the present invention will be described.
First, the reasons for limiting the molten steel components when manufacturing this electromagnetic steel sheet will be described below.
If C in the molten steel exceeds 0.08 mass%, it is difficult to reduce the content to 50 ppm or less, which is the C content in which no magnetic aging occurs in the steel sheet, so the amount is limited to 0.08 mass% or less. In particular, it is desirable to reduce to 50 ppm or less at the raw material stage in order to obtain a smooth product surface by performing recrystallization annealing in a dry atmosphere and omitting decarburization. Alternatively, in the case of a material having a high amount of C, it is possible to decarburize in a low-oxidation atmosphere during the flattening annealing after the final finish annealing.
[0031]
Mn is an element necessary for improving the hot workability, but if it is less than 0.005 mass%, there is no effect, whereas if it exceeds 3.0 mass%, the magnetic flux density decreases, so 0.005 to 3.0 mass%. To do.
[0032]
It is necessary to reduce sol. Al to 100 ppm or less and N to 50 ppm or less, preferably 30 ppm or less, in order to achieve secondary recrystallization satisfactorily.
Further, S and Se, which are precipitate forming elements, must be reduced to 50 ppm or less, preferably 30 ppm or less, respectively.
[0033]
The molten steel having the above components may be formed into a slab by a normal normal ingot forming method or a continuous casting method, or a thin cast piece having a thickness of 100 mm or less may be produced by a direct casting method. Subsequent hot rolling may be performed by hot-rolled sheet annealing as necessary. Here, as described above, the rough rolling exit temperature T (° C.) of hot rolling,
T ≧ 3.14 × [S (ppm)] + 1.28 × [Se (ppm)] + 1.14 × [Al (ppm)] + 842
It is necessary to control according to.
[0034]
Next, after one or two or more cold rollings with intermediate annealing, recrystallization annealing is performed in an atmosphere with a dew point of 40 ° C or lower, and then final finish annealing is performed in an atmosphere with a dew point of 40 ° C or lower. Then, a grain-oriented electrical steel sheet having no undercoat mainly composed of forsterite (Mg ₂ SiO ₄ ) is produced.
Here, the recrystallization annealing after the final cold rolling is preferably performed in the range of 800 to 1000 ° C. The recrystallization annealing is performed in an atmosphere having a dew point of 40 ° C. or lower. If the dew point is too high, an oxide is formed on the surface of the steel sheet and good iron loss cannot be obtained.
[0035]
Moreover, in order not to cause magnetic aging due to C, it is necessary to reduce C to 50 ppm or less, but when using a material containing 50 ppm or less as a molten steel component, there is no need for decarburization. Making the C of the molten steel component 50 ppm or less and making the recrystallization annealing atmosphere non-oxidizing at 0 ° C. or less is effective for reducing the formation of oxides on the steel sheet surface.
[0036]
Then, a secondary recrystallization structure is developed by performing final finish annealing. The atmosphere of the final finish annealing must be suppressed to a dew point of 40 ° C. or lower for the same reason as the recrystallization annealing.
[0037]
【Example】
Example 1
C: 0.0030 mass%, Si: 3.2 mass% and Mn: 0.05 mass%, and Al is 30 ppm, N is 15 ppm, Se is 10 ppm, S is 5, 10, 20, 30, 40 ppm, A steel slab having a composition in which other components were reduced to 10 ppm or less in total was produced by continuous casting. Subsequently, after heating the slab to 1200 ° C., the rough rolling exit temperature was adjusted to various temperatures shown in Table 1 and hot rolling was performed to obtain a 2.5 mm thickness. Thereafter, it was soaked at 900 ° C. for 1 minute in an N ₂ atmosphere and then rapidly cooled.
[0038]
Next, after a final sheet thickness of 0.35 mm was obtained by cold rolling, recrystallization annealing was performed at 900 ° C. for 10 seconds in an atmosphere of 50 vol% hydrogen, 50 vol% nitrogen, and dew point of −10 ° C. Thereafter, in a nitrogen atmosphere having a dew point of −20 ° C. or lower, the temperature was raised from room temperature to 875 ° C. at a rate of 50 ° C./h, and final finish annealing was performed according to the condition of holding at that temperature for 50 hours.
[0039]
The iron loss and magnetic flux density of the product plate thus obtained were measured. As shown in Table 1, the results are as follows: S: 5 ppm and 10 ppm, rough rolling delivery temperature: 950 ° C or more, S: 20 ppm and 30 ppm, 1000 ° C or more, S: 40 ppm, 1050 ° C or more Thus, good magnetic characteristics of B ₈ : 1.83 T or more were obtained.
[0040]
[Table 1]

[0041]
Example 2
C: 0.0030 mass%, Si: 3.2 mass%, Al: 25 ppm and Mn: 0.05 mass%, N: 15 ppm, S: 5 ppm, Se is four levels of 20, 30, 40, 50 ppm A steel slab having a composition in which other components were reduced to 10 ppm or less in total was produced by continuous casting. Next, the slab was heated to 1200 ° C., and the rough rolling exit temperature was adjusted to various temperatures shown in Table 2 to perform hot rolling to finish 2.5 mm. Thereafter, it was soaked at 900 ° C. for 1 minute in an N ₂ atmosphere and then rapidly cooled.
[0042]
Next, after a final sheet thickness of 0.35 mm was obtained by cold rolling, recrystallization annealing was performed at 900 ° C. for 10 seconds in an atmosphere of 50 vol% hydrogen, 50 vol% nitrogen, and dew point of −10 ° C. Thereafter, in a nitrogen atmosphere having a dew point of −20 ° C. or lower, the temperature was raised from room temperature to 875 ° C. at a rate of 50 ° C./h, and final finish annealing was performed according to the condition of holding at that temperature for 50 hours.
[0043]
The iron loss and magnetic flux density of the product plate thus obtained were measured. As shown in Table 2, the results are shown in Table 2. When Se: 10 ppm, the rough rolling exit temperature is 900 ° C. or higher, and Se: 20 ppm, 30 ppm and 40 ppm are 950 ° C. or higher, and B _{8 is} 1.83 T or higher. Magnetic properties were obtained.
[0044]
[Table 2]

[0045]
Example 3
C: 0.0030mass%, Si: 3.2mass%, Mn: 0.05mass% and N: 15ppm, S: 5ppm, Se: 10ppm, Al is three levels of 20, 50, 80ppm, and other components Steel slabs with a composition reduced to a total of 10 ppm or less were produced by continuous casting. Next, the slab was heated to 1200 ° C., and then the rough rolling outlet temperature was adjusted to various temperatures shown in Table 3 to perform hot rolling to finish 2.5 mm. Thereafter, it was soaked at 900 ° C. for 1 minute in an N ₂ atmosphere and then rapidly cooled.
[0046]
Next, after a final sheet thickness of 0.35 mm was obtained by cold rolling, recrystallization annealing was performed at 900 ° C. for 10 seconds in an atmosphere of 50 vol% hydrogen, 50 vol% nitrogen, and dew point of −10 ° C. Thereafter, in a nitrogen atmosphere having a dew point of −20 ° C. or lower, the temperature was raised from room temperature to 875 ° C. at a rate of 50 ° C./h, and final finish annealing was performed according to the condition of holding at that temperature for 50 hours.
[0047]
The iron loss and magnetic flux density of the product plate thus obtained were measured. The results, as shown in Table 3, Al: 20 ppm In rough rolling delivery temperature: at 900 ° C. or higher, Al: at 50ppm in the 950 ° C. or higher, and Al: at the 80ppm same 1000 ° C. or higher, B ₈ : Good magnetic characteristics of 1.83 T or more were obtained.
[0048]
[Table 3]

[0049]
【The invention's effect】
According to the present invention, there is no underlying coating (glass coating) mainly composed of forsterite (Mg ₂ SiO ₄ ), so that the grain-oriented electrical steel sheet has excellent punchability and has stable magnetic characteristics in the coil length direction. Can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing the shape of an EI type core.
FIG. 2 is a diagram showing B ₈ when the amount of impurities S and the temperature at the side of rough rolling during hot rolling are changed.
FIG. 3 is a diagram showing B ₈ when the amount of impurity Se and the temperature at the side of rough rolling during hot rolling are changed.
FIG. 4 is a diagram showing B ₈ when the amount of impurity Al and the temperature at the side of rough rolling during hot rolling are changed.

Claims (1)

C: 0.08 mass% or less, Si: 2.0-8.0 mass% and Mn: 0.005-3.0 mass%, sol. A slab produced using molten steel consisting of Fe and unavoidable impurities, with Al reduced to 100 ppm or less and N reduced to 50 ppm or less, and S and Se reduced to 50 ppm or less, respectively, and then 1 After performing cold rolling at least twice with intermediate or intermediate annealing, perform recrystallization annealing in an atmosphere with a dew point of 40 ° C or lower, and then perform final finish annealing in an atmosphere with a dew point of 40 ° C or lower. When producing a grain-oriented electrical steel sheet having no undercoat mainly composed of forsterite (Mg ₂ SiO ₄ ), the hot rolling rough rolling outlet temperature T ( ° C.) determines the target value of the method of Do we have ways oriented electrical steel sheet having a base film and controlling the hot rolling so as to satisfy the target value.
Serial T ≧ 3.14 × [S (ppm )] + 1.28 × [Se (ppm)] + 1.14 × [Al (ppm)] + 842

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