JP2012144776A - Method of manufacturing grain-oriented electromagnetic steel sheet - Google Patents
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本発明は方向性電磁鋼板の磁気特性を向上させるための製造方法に関するものである。 The present invention relates to a manufacturing method for improving the magnetic properties of grain-oriented electrical steel sheets.
方向性電磁鋼板は主に電力用トランスコア材料に用いられるため、低鉄損であることが必要である。方向性電磁鋼板の製造方法は、最終板厚とした冷延鋼板に脱炭焼鈍を施した後、二次再結晶と純化を目的とした仕上げ焼鈍を経た後、鋼板表面に皮膜を形成する工程を経る。このようにして得られた方向性電磁鋼板は先鋭な（110）〔001〕集合組織（ゴス方位）を有したSi含有鋼板と、その表面に形成された数ミクロンの無機質皮膜からなる。
鋼板がゴス方位を持つことが方向性電磁鋼板の低鉄損特性を実現するために不可欠な条件であり、この組織を実現するために仕上げ焼鈍中にゴス方位粒子が選択的に成長する二次再結晶と呼ばれる粒成長が利用されている。二次再結晶を安定的に引き起こすため、方向性電磁鋼板ではインヒビターと称する鋼中の微細析出物が利用されている。インヒビターは仕上げ焼鈍中低温部では粒成長を抑制し、一定の温度以上では分解あるいは粗大化によってピン止め効果を失って二次再結晶を引き起こすもので、硫化物や窒化物が一般的に利用される。望ましい組織を得るためにはインヒビターを一定の温度まで保持することが必要であり、硫化物であれば仕上げ焼鈍の硫黄成分分圧、窒化物であれば窒素分圧を制御することなどで目的を達する。インヒビターとして使用される硫化物や窒化物は仕上げ焼鈍中の昇温途中で起こる二次再結晶のために必要ではあるが、これらが製品中に残留すると製品の鉄損を著しく悪化させる。硫化物や窒化物の影響を鋼中から除くために、二次再結晶完了後、純水素中1200℃前後で長時間保定を行う。これを純化焼鈍と称する。したがって、純化焼鈍は仕上げ焼鈍中における高温保定状態のことである。
The grain-oriented electrical steel sheet is mainly used as a power transformer core material, and therefore needs to have low iron loss. The method for producing grain-oriented electrical steel sheets is a process of forming a film on the steel sheet surface after decarburizing and annealing to the final thickness of the cold-rolled steel sheet, followed by finish annealing for the purpose of secondary recrystallization and purification. Go through. The grain-oriented electrical steel sheet thus obtained is composed of a Si-containing steel sheet having a sharp (110) [001] texture (Goss orientation) and an inorganic coating of several microns formed on the surface thereof.
It is an indispensable condition for the steel sheet to have goth orientation to achieve the low iron loss characteristics of grain-oriented electrical steel sheets, and secondary to the growth of goth-oriented grains selectively during finish annealing to achieve this structure. Grain growth called recrystallization is used. In order to cause secondary recrystallization stably, fine grain precipitates in steel called inhibitors are used in grain oriented electrical steel sheets. Inhibitors suppress grain growth at low temperatures during finish annealing, and cause pinning effects due to decomposition or coarsening above a certain temperature and cause secondary recrystallization. Sulfides and nitrides are generally used. The In order to obtain a desired structure, it is necessary to keep the inhibitor at a certain temperature. For sulfides, the sulfur component partial pressure of finish annealing is controlled, and for nitrides, the nitrogen partial pressure is controlled. Reach. Although sulfides and nitrides used as inhibitors are necessary for secondary recrystallization that occurs in the course of temperature increase during finish annealing, if these remain in the product, the iron loss of the product is significantly worsened. In order to remove the influence of sulfides and nitrides from the steel, after secondary recrystallization is completed, it is held for a long time at around 1200 ° C in pure hydrogen. This is called purification annealing. Accordingly, purification annealing is a high temperature holding state during finish annealing.
本発明者らによる種々の検討の結果、良好な二次再結晶を得るためには、熱延板のBが安定な析出物の形態で析出している必要があることが明らかとなった。このようなBの性状を分析した結果、スパーク放電発光分光分析のPSA分析結果でinsol Bに相当する値が一定量以上確保すると、良好な二次再結晶が得られ、磁気特性が向上することが明らかとなった。 As a result of various studies by the present inventors, it has been found that in order to obtain a good secondary recrystallization, B of the hot-rolled sheet needs to be precipitated in the form of a stable precipitate. As a result of analyzing the properties of B as described above, if a value equivalent to insol B is secured in a certain amount or more in the PSA analysis result of spark discharge optical emission spectrometry, good secondary recrystallization can be obtained and the magnetic properties can be improved. Became clear.
QV-PSA分析については特許文献１に詳細な技術内容の開示がある。
Regarding the QV-PSA analysis,
本発明の目的は、良好な磁気特性を有する方向性電磁鋼板を得るための手段を提供することである。 An object of the present invention is to provide means for obtaining a grain-oriented electrical steel sheet having good magnetic properties.
（１）質量％で、Siを0.8〜7％、酸可溶性Alを0.01〜0.065％、Nを0.004〜0.012％、Mnを0.05〜1％、Bを0.0005〜0.0080％含有し、S及びSeからなる群から選択された少なくとも１種を総量で0.003〜0.015％含有し、C含有量が0.085％以下であり、残部がFeおよび不可避的不純物からなる電磁鋼板素材において、熱延工程を経た後の鋼中のBをスパーク放電発光分光分析法によるPSA分析において、
SInsolB≧5%・・・・(式1)
であることを特徴とする熱延鋼板。
ただし、SInsol Bは、発光分光分析法を用いて、放電により得られる特定成分の発光強度を順に並べ替えたパルス強度順位図を作成して、下記（式２）、（式３）及び（式４）式により得られる値である。
Insol.成分量測定値 ＝ ｛Sall−N×F(N/2)｝… （式２）
Total量測定値＝ N×F(N/2)…（式３）
Sinsol B= （Insol.成分量測定値/ Total量測定値）×100…（式４）
ここで、Ｎは放電により得られた全パルス数から発光不良データを除いたパルス数であり、Ｓallは発光パルス強度x=1からNまでの全積分値であり、Ｆ（Ｎ／２）は、パルス強度順に並び替えた時、中間順位値となる強度値であり、ｙ＝Ｆ（ｘ）はｘ＝１からＮ／２までのパルス強度値を表現する関数である。
（２）質量％で、Siを0.8〜7％、酸可溶性Alを0.01〜0.065％、Nを0.004〜0.012％、Mnを0.05〜1％、Bを0.0005〜0.0080％含有し、S及びSeからなる群から選択された少なくとも１種を総量で0.003〜0.015％含有し、C含有量が0.085％以下であり、残部がFeおよび不可避的不純物からなる電磁鋼板素材を所定の温度で加熱する工程と、
加熱された前記珪素鋼素材の熱間圧延を行って熱間圧延鋼帯を得る工程と、
前記熱間圧延鋼帯の焼鈍を行って、焼鈍鋼帯を得る工程と、
前記焼鈍鋼帯を１回以上、冷間圧延して冷間圧延鋼帯を得る工程と、
前記冷間圧延鋼帯の脱炭焼鈍を行って、一次再結晶が生じた脱炭焼鈍鋼帯を得る工程と、
ＭｇＯを主成分とする焼鈍分離剤を前記脱炭焼鈍鋼帯に塗布する工程と、
前記脱炭焼鈍鋼帯の仕上げ焼鈍により、二次再結晶を生じさせる工程と、
を有し、
更に、前記脱炭焼鈍の開始から仕上げ焼鈍における二次再結晶の発現までの間に、前記脱炭焼鈍鋼帯のＮ含有量を増加させる窒化処理を行う工程を有し、
前記所定の温度は、
前記珪素鋼素材にＳ及びＳｅが含有されている場合、下記(式５)で表される温度Ｔ１（℃）以下、下記(式６)で表される温度Ｔ２（℃）以下、かつ下記(式７)で表わされる温度Ｔ３（℃）以下であり、
前記珪素鋼素材にＳｅが含有されていない場合、下記(式５)で表される温度Ｔ１（℃）以下、かつ下記(式７)で表わされる温度Ｔ３（℃）以下であり、
前記珪素鋼素材にＳが含有されていない場合、下記(式６)で表される温度Ｔ２（℃）以下、かつ下記(式７)で表わされる温度Ｔ３（℃）以下であり、
前記熱間圧延鋼帯中のＢＮ、ＭｎＳ及びＭｎＳｅの量は下記(式８)、(式９)及び(式１０)を満たすことを特徴とする（１）または（２）に記載の方向性電磁鋼板の製造方法。
(1) Containing 0.8 to 7% Si, 0.01 to 0.065% acid-soluble Al, 0.004 to 0.012% N, 0.05 to 1% Mn, 0.0005 to 0.0080% B, and 0.005 to 0.0080% B In the electrical steel sheet material containing at least one selected from the group consisting of 0.003 to 0.015% in total, C content of 0.085% or less, and the balance consisting of Fe and inevitable impurities, after undergoing a hot rolling process In PSA analysis of B in steel by spark discharge optical emission spectrometry,
S Insol B ≧ 5% ・ ・ ・ ・ (Formula 1)
A hot-rolled steel sheet characterized by
However, S Insol B uses an emission spectroscopic analysis method to create a pulse intensity ranking diagram in which the emission intensities of specific components obtained by discharge are rearranged in order, and the following (Equation 2), (Equation 3) and ( This is a value obtained from the equation (4).
Insol. Measured component amount = {Sall-N x F (N / 2)} (Formula 2)
Total amount measured value = N x F (N / 2) (Equation 3)
S insol B = (Insol. Component amount measurement value / Total amount measurement value) × 100 (Equation 4)
Here, N is the number of pulses obtained by removing light emission failure data from the total number of pulses obtained by discharge, Sall is the total integrated value from light emission pulse intensity x = 1 to N, and F (N / 2) is The intensity values are intermediate rank values when rearranged in order of pulse intensity, and y = F (x) is a function expressing the pulse intensity values from x = 1 to N / 2.
(2) By mass%, containing 0.8 to 7% Si, 0.01 to 0.065% acid-soluble Al, 0.004 to 0.012% N, 0.05 to 1% Mn, 0.0005 to 0.0080% B, and from S and Se A step of heating at a predetermined temperature an electrical steel sheet material containing at least one selected from the group consisting of 0.003 to 0.015% in total, having a C content of 0.085% or less, and the balance being Fe and inevitable impurities; ,
Performing a hot rolling of the heated silicon steel material to obtain a hot rolled steel strip; and
Annealing the hot rolled steel strip to obtain an annealed steel strip; and
Cold-rolling the annealed steel strip at least once to obtain a cold-rolled steel strip; and
Performing decarburization annealing of the cold-rolled steel strip to obtain a decarburized annealed steel strip in which primary recrystallization has occurred; and
Applying an annealing separator mainly composed of MgO to the decarburized annealing steel strip;
A step of producing secondary recrystallization by finish annealing of the decarburized annealed steel strip;
Have
Furthermore, between the start of the decarburization annealing and the expression of secondary recrystallization in the finish annealing, there is a step of performing a nitriding treatment to increase the N content of the decarburized annealing steel strip,
The predetermined temperature is
When S and Se are contained in the silicon steel material, the temperature T1 (° C.) or less represented by the following (formula 5), the temperature T2 (° C.) or less represented by the following (formula 6), and the following ( It is below the temperature T3 (° C.) represented by the equation (7),
When Se is not contained in the silicon steel material, the temperature T1 (° C.) or less represented by the following (formula 5) and the temperature T3 (° C.) or less represented by the following (formula 7),
When the silicon steel material does not contain S, the temperature T2 (° C.) or less represented by the following (formula 6) and the temperature T3 (° C.) or less represented by the following (formula 7),
The directionality according to (1) or (2), wherein the amount of BN, MnS and MnSe in the hot-rolled steel strip satisfies the following (Formula 8), (Formula 9) and (Formula 10): A method for producing electrical steel sheets.
T1=14855/(6.82-log([Mn]×[S]))-273 ・・・(式５)
T2=10733/(4.08-log([Mn]×[Se]))-273 ・・・(式６)
T3=16000/(5.92-log([B]×[N]))-273 ・・・(式７)
BasBN≧0.0005 ・・・(式８)
[B]―BasBN≦0.001 ・・・(式９)
SasMnS+0.5×SeasMnSe≧0.002 ・・・(式１０)
ここで、［Ｍｎ］は前記珪素鋼素材のＭｎ含有量（質量％）を示し、［Ｓ］は前記珪素鋼素材のＳ含有量（質量％）を示し、［Ｓｅ］は前記珪素鋼素材のＳｅ含有量（質量％）を示し、［Ｂ］は前記珪素鋼素材のＢ含有量（質量ｐｐｍ）を示し、［Ｎ］は前記珪素鋼素材のＮ含有量（質量ｐｐｍ）を示し、ＢａｓＢＮは前記熱間圧延鋼帯中にＢＮとして析出しているＢの量（質量％）を示し、ＳａｓＭｎＳは前記熱間圧延鋼帯中にＭｎＳとして析出しているＳの量（質量％）を示し、ＳｅａｓＭｎＳｅは前記熱間圧延鋼帯中にＭｎＳｅとして析出しているＳｅの量（質量％）を示す。
（３）前記電磁鋼板素材が、更に、質量％で、Ｃｒ：０．３％以下、Ｃｕ：０．４％以下、Ｎｉ：１％以下、Ｐ：０．５％以下、Ｍｏ：０．１％以下、Ｓｎ：０．３％以下、Ｓｂ：０．３％以下、及びＢｉ：０．０１％以下からなる群から選択された少なくとも１種を含有することを特徴とする前項（3）に記載の方向性電磁鋼板の製造方法である。
T1 = 14855 / (6.82-log ([Mn] × [S]))-273 (Expression 5)
T2 = 10733 / (4.08-log ([Mn] × [Se]))-273 (Expression 6)
T3 = 16000 / (5.92-log ([B] × [N]))-273 (Expression 7)
B asBN ≧ 0.0005 (Equation 8)
[B] -B asBN ≦ 0.001 (Equation 9)
S asMnS + 0.5 × Se asMnSe ≧ 0.002 (Equation 10)
Here, [Mn] represents the Mn content (mass%) of the silicon steel material, [S] represents the S content (mass%) of the silicon steel material, and [Se] represents the silicon steel material. Se content (mass%) is indicated, [B] indicates the B content (mass ppm) of the silicon steel material, [N] indicates the N content (mass ppm) of the silicon steel material, and B asBN Indicates the amount (mass%) of B precipitated as BN in the hot-rolled steel strip, and S asMnS indicates the amount (mass%) of S precipitated as MnS in the hot-rolled steel strip. Se asMnSe indicates the amount (mass%) of Se precipitated as MnSe in the hot-rolled steel strip.
(3) The magnetic steel sheet material is further mass%, Cr: 0.3% or less, Cu: 0.4% or less, Ni: 1% or less, P: 0.5% or less, Mo: 0.1 % Or less, Sn: 0.3% or less, Sb: 0.3% or less, and Bi: 0.01% or less, and containing at least one selected from the group consisting of 0.01% or less It is a manufacturing method of the grain-oriented electrical steel sheet of description.
本発明によれば、良好な磁気特性を有する方向性電磁鋼板が得られる。 According to the present invention, a grain-oriented electrical steel sheet having good magnetic properties can be obtained.
析出物性状の規定には種々の方法があるが、QV-PSA法は迅速に決定可能で,有効性の高い評価指標であることが明らかとなった。この方法は、特許文献１に有るような、insol介在物を評価する手法である。本発明者らは、BのQV-PSA解析結果で（式１）の条件が満たされると、良好な磁気特性が得られることを見出した。
There are various methods for defining the properties of precipitates, but the QV-PSA method can be determined quickly and has proved to be a highly effective evaluation index. This method is a method for evaluating insol inclusions as disclosed in
このQV-PSA解析を以下の実験の詳細にある種々の条件にて作成した試料について実施し、磁気特性との関係を調査したところ、図１の結果を得た。 This QV-PSA analysis was carried out on samples prepared under various conditions in the details of the following experiment, and the relationship with the magnetic properties was investigated. The result shown in FIG. 1 was obtained.
このような析出物性状を実現するためには、課題を解決する手段の（２）に記載したように、Siを初めとする成分を規定し、この電磁鋼板素材を所定の温度にて処理すること、あるいは課題を解決する手段の（３）に記載した方法によればよい。
＜実験の詳細＞
以上のような知見を得るに至った試験の内容を以下に述べる。まず析出物と磁性、皮膜密着性の関係についてSを含む組成を有する珪素鋼素材について調査する試験を行った。成分としてＳｉ：３．３質量％、Ｃ：０．０６質量％、酸可溶性Ａｌ：０．０２７質量％、Ｎ：０．００８質量％、Ｍｎ：０．０５質量％〜０．１９質量％、Ｓ：０．００７質量％、及びＢ：０．００１０質量％〜０．００３５質量％を含有し、残部がＦｅ及び不可避的不純物からなる種々の珪素鋼スラブを得た。次いで、珪素鋼スラブを１１００℃〜１２５０℃の温度で加熱し、熱間圧延を行った。熱間圧延では、粗圧延を１０５０℃で行った後、仕上げ圧延を１０００℃で行って厚さが２．３ｍｍの熱間圧延鋼帯を得た。そして、熱間圧延鋼帯に冷却水を噴射して５５０℃まで冷却し、その後、大気中で冷却した。続いて、熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、１５℃／ｓの速度で冷間圧延鋼帯を加熱し、８４０℃の温度で脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２２質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、仕上げ焼鈍を行った。このようにして種々の試料を作製した。
In order to realize such precipitate properties, as described in (2) of the means for solving the problem, the components including Si are defined, and this electrical steel sheet material is processed at a predetermined temperature. Or the method described in (3) of the means for solving the problem.
<Details of experiment>
The contents of the tests that led to the above findings are described below. First, a test was conducted to investigate a silicon steel material having a composition containing S with respect to the relationship between precipitates, magnetism, and film adhesion. As components, Si: 3.3% by mass, C: 0.06% by mass, acid-soluble Al: 0.027% by mass, N: 0.008% by mass, Mn: 0.05% by mass to 0.19% by mass, Various silicon steel slabs containing S: 0.007 mass% and B: 0.0010 mass% to 0.0035 mass% with the balance being Fe and inevitable impurities were obtained. Next, the silicon steel slab was heated at a temperature of 1100 ° C. to 1250 ° C. to perform hot rolling. In hot rolling, after rough rolling was performed at 1050 ° C., finish rolling was performed at 1000 ° C. to obtain a hot rolled steel strip having a thickness of 2.3 mm. And it cooled to 550 degreeC by injecting cooling water to a hot-rolled steel strip, and cooled in air | atmosphere after that. Subsequently, the hot rolled steel strip was annealed. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, the cold-rolled steel strip was heated at a rate of 15 ° C./s, and decarburized and annealed at a temperature of 840 ° C. to obtain a decarburized and annealed steel strip. Subsequently, the decarburized and annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.022% by mass. Subsequently, the annealing separator which has MgO as a main component was apply | coated, and final annealing was performed. In this way, various samples were prepared.
そして、熱間圧延鋼帯中の析出物と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図２に示す。縦軸はＢＮの析出量をＢに換算した値（質量％）を示す。横軸はＭｎＳとして析出したＳの量（質量％）に相当する。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。図２に示すように、ＭｎＳ及びＢＮの析出量が一定値未満の試料では、磁束密度Ｂ８が低かった。このことは、二次再結晶が不安定であったことを示す。 And the relationship between the precipitates in the hot rolled steel strip and the magnetic properties after finish annealing was investigated. The result is shown in FIG. The vertical axis represents the value (mass%) obtained by converting the precipitation amount of BN into B. The horizontal axis corresponds to the amount (mass%) of S deposited as MnS. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. As shown in FIG. 2, the magnetic flux density B8 was low in the sample in which the amount of MnS and BN deposited was less than a certain value. This indicates that secondary recrystallization was unstable.
更に、ＭｎＳ及びＢＮが一定量以上析出している試料について、ＢＮとして析出していないＢの量と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図３に示す。図３の横軸はＢ含有量（質量％）を示し、縦軸はＢＮの析出量をＢに換算した値（質量％）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。図３に示すように、ＢＮとして析出していないＢの量が一定値以上である試料では、磁束密度Ｂ８が低かった。このことは、二次再結晶が不安定であったことを示す。 Furthermore, the relationship between the amount of B not precipitated as BN and the magnetic properties after finish annealing was investigated for samples in which a predetermined amount or more of MnS and BN were precipitated. The result is shown in FIG. The horizontal axis of FIG. 3 shows the B content (mass%), and the vertical axis shows the value (mass%) obtained by converting the precipitation amount of BN into B. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. As shown in FIG. 3, in the sample in which the amount of B not precipitated as BN is a certain value or more, the magnetic flux density B8 is low. This indicates that secondary recrystallization was unstable.
磁気特性が良好な試料について析出物の形態を調査した結果、ＭｎＳを核としてＢＮがＭｎＳの周辺に複合析出していることが判明した。このような複合析出物は二次再結晶を安定化させるインヒビターとして有効である。 As a result of investigating the form of the precipitate for the sample having good magnetic properties, it was found that BN was compositely precipitated around MnS with MnS as a nucleus. Such a composite precipitate is effective as an inhibitor that stabilizes secondary recrystallization.
また、熱間圧延の条件と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図４及び図５に示す。 In addition, the relationship between hot rolling conditions and magnetic properties after finish annealing was investigated. The results are shown in FIGS.
図４の横軸はＭｎ含有量（質量％）を示し、縦軸は熱間圧延時のスラブ加熱の温度（℃）を示す。図５の横軸はＢ含有量（質量％）を示し、縦軸は熱間圧延時のスラブ加熱の温度（℃）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。また、図４中の曲線は、下記式（２）で表わされるＭｎＳの溶体化温度Ｔ１（℃）を示し、図５中の曲線は、下記式（４）で表わされるＢＮの溶体化温度Ｔ３（℃）を示している。図４に示すように、Ｍｎ含有量に応じて定まる温度以下でスラブ加熱を行った試料において、高い磁束密度Ｂ８が得られることが判明した。更に、この温度はＭｎＳの溶体化温度Ｔ１とほぼ一致していることも判明した。また、図５に示すように、Ｂ含有量に応じて定まる温度以下でスラブ加熱を行った試料において、高い磁束密度Ｂ８が得られることも判明した。更に、この温度はＢＮの溶体化温度Ｔ３とほぼ一致していることも判明した。つまり、スラブ加熱を、ＭｎＳ及びＢＮが完全固溶しない温度域で行うことが有効であることが判明した。 The horizontal axis in FIG. 4 indicates the Mn content (% by mass), and the vertical axis indicates the slab heating temperature (° C.) during hot rolling. The horizontal axis of FIG. 5 shows B content (mass%), and a vertical axis | shaft shows the temperature (degreeC) of the slab heating at the time of hot rolling. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. The curve in FIG. 4 shows the solution temperature T1 (° C.) of MnS represented by the following formula (2), and the curve in FIG. 5 shows the solution temperature T3 of BN represented by the following formula (4). (° C.). As shown in FIG. 4, it was found that a high magnetic flux density B8 can be obtained in a sample subjected to slab heating at a temperature that is determined according to the Mn content. Furthermore, it was also found that this temperature almost coincided with the solution temperature T1 of MnS. Further, as shown in FIG. 5, it was also found that a high magnetic flux density B8 can be obtained in a sample subjected to slab heating at a temperature determined according to the B content. Furthermore, it was also found that this temperature almost coincided with the solution temperature T3 of BN. That is, it has been found that it is effective to perform slab heating in a temperature range where MnS and BN are not completely dissolved.
T1=14855/(6.82-log([Mn]×[S]))-273 ・・・（式５）
T3=16000/(5.92-log([B]×[N]))-273 ・・・（式７）
ここで、［Ｍｎ］はＭｎ含有量（質量％）を示し、［Ｓ］はＳ含有量（質量％）を示し、［Ｂ］はＢ含有量（質量ｐｐｍ）を示し、［Ｎ］はＮ含有量（質量ｐｐｍ）を示す。
T1 = 14855 / (6.82-log ([Mn] × [S]))-273 (Expression 5)
T3 = 16000 / (5.92-log ([B] × [N]))-273 (Expression 7)
Here, [Mn] represents the Mn content (mass%), [S] represents the S content (mass%), [B] represents the B content (mass ppm), and [N] represents N Content (mass ppm) is shown.
更にＢＮの析出挙動を調査した結果、その析出温度域が８００℃〜１０００℃であることが判明した。 Furthermore, as a result of investigating the precipitation behavior of BN, the precipitation temperature range was found to be 800 ° C to 1000 ° C.
また、本発明者らは、熱間圧延の仕上げ圧延の終了温度について調査した。この調査では、先ず、Ｓｉ：３．３質量％、Ｃ：０．０６質量％、酸可溶性Ａｌ：０．０２７質量％、Ｎ：０．００８質量％、Ｍｎ：０．１質量％、Ｓ：０．００７質量％、及びＢ：０．００１質量％〜０．００４質量％を含有し、残部がＦｅ及び不可避的不純物からなる種々の珪素鋼スラブを得た。次いで、珪素鋼スラブを１２００℃の温度で加熱し、熱間圧延を行った。熱間圧延では、粗圧延を１０５０℃で行った後、仕上げ圧延を１０２０℃〜９００℃で行って厚さが２．３ｍｍの熱間圧延鋼帯を得た。そして、熱間圧延鋼帯に冷却水を噴射して５５０℃まで冷却し、その後、大気中で冷却した。続いて、熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、１５℃／ｓの速度で冷間圧延鋼帯を加熱し、８４０℃の温度で脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２２質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、仕上げ焼鈍を行った。このようにして種々の試料を作製した。 In addition, the present inventors investigated the end temperature of hot rolling finish rolling. In this investigation, first, Si: 3.3 mass%, C: 0.06 mass%, acid-soluble Al: 0.027 mass%, N: 0.008 mass%, Mn: 0.1 mass%, S: Various silicon steel slabs containing 0.007% by mass and B: 0.001% by mass to 0.004% by mass with the balance being Fe and inevitable impurities were obtained. Next, the silicon steel slab was heated at a temperature of 1200 ° C. and hot rolled. In hot rolling, after rough rolling was performed at 1050 ° C., finish rolling was performed at 1020 ° C. to 900 ° C. to obtain a hot rolled steel strip having a thickness of 2.3 mm. And it cooled to 550 degreeC by injecting cooling water to a hot-rolled steel strip, and cooled in air | atmosphere after that. Subsequently, the hot rolled steel strip was annealed. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, the cold-rolled steel strip was heated at a rate of 15 ° C./s, and decarburized and annealed at a temperature of 840 ° C. to obtain a decarburized and annealed steel strip. Subsequently, the decarburized and annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.022% by mass. Subsequently, the annealing separator which has MgO as a main component was apply | coated, and final annealing was performed. In this way, various samples were prepared.
そして、熱間圧延の仕上げ圧延の終了温度と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図６に示す。図６の横軸はＢ含有量（質量％）を示し、縦軸は仕上げ圧延の終了温度Ｔｆを示す。また、白丸は磁束密度Ｂ８が1.91Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が1.91Ｔ未満であったことを示している。図６に示すように、仕上げ圧延の終了温度Ｔｆが、下記（式１１）を満たしている場合に、高い磁束密度Ｂ８が得られることが判明した。これは、仕上げ圧延の終了温度Ｔｆの制御によって、ＢＮの析出が更に促進されたためであると考えられる。 And the relationship between the finishing temperature of the finish rolling of hot rolling and the magnetic properties after finish annealing was investigated. The result is shown in FIG. The horizontal axis in FIG. 6 represents the B content (% by mass), and the vertical axis represents the finish rolling finish temperature Tf. A white circle indicates that the magnetic flux density B8 is 1.91 T or more, and a black square indicates that the magnetic flux density B8 is less than 1.91 T. As shown in FIG. 6, it was found that a high magnetic flux density B8 can be obtained when the finish rolling finish temperature Tf satisfies the following (formula 11). This is considered to be because precipitation of BN was further promoted by controlling the finish rolling finish temperature Tf.
Ｔｆ≦１０００−１００００ｘ［Ｂ］ ・・・（式１１）
次に、析出物と磁性、皮膜密着性の関係についてSeを含む組成を有する珪素鋼素材について調査する試験を行った。鋼組成Ｓｉ：３．３質量％、Ｃ：０．０６質量％、酸可溶性Ａｌ：０．０２８質量％、Ｎ：０．００７質量％、Ｍｎ：０．０５質量％〜０．２０質量％、Ｓｅ：０．００７質量％、及びＢ：０．００１０質量％〜０．００３５質量％を含有し、残部がＦｅ及び不可避的不純物からなる種々の珪素鋼スラブを得た。次いで、珪素鋼スラブを１１００℃〜１２５０℃の温度で加熱し、熱間圧延を行った。熱間圧延では、粗圧延を１０５０℃で行った後、仕上げ圧延を１０００℃で行って厚さが２．３ｍｍの熱間圧延鋼帯を得た。そして、熱間圧延鋼帯に冷却水を噴射して５５０℃まで冷却し、その後、大気中で冷却した。続いて、熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、１５℃／ｓの速度で冷間圧延鋼帯を加熱し、８５０℃の温度で脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２３質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、仕上げ焼鈍を行った。このようにして種々の試料を作製した。
Tf ≦ 1000−10000 × [B] (Formula 11)
Next, the test which investigates about the silicon steel raw material which has a composition containing Se about the relationship between a deposit, magnetism, and film | membrane adhesiveness was done. Steel composition Si: 3.3 mass%, C: 0.06 mass%, acid-soluble Al: 0.028 mass%, N: 0.007 mass%, Mn: 0.05 mass% to 0.20 mass%, Various silicon steel slabs containing Se: 0.007% by mass and B: 0.0010% by mass to 0.0035% by mass with the balance being Fe and inevitable impurities were obtained. Next, the silicon steel slab was heated at a temperature of 1100 ° C. to 1250 ° C. to perform hot rolling. In hot rolling, after rough rolling was performed at 1050 ° C., finish rolling was performed at 1000 ° C. to obtain a hot rolled steel strip having a thickness of 2.3 mm. And it cooled to 550 degreeC by injecting cooling water to a hot-rolled steel strip, and cooled in air | atmosphere after that. Subsequently, the hot rolled steel strip was annealed. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, the cold-rolled steel strip was heated at a rate of 15 ° C./s, and decarburized and annealed at a temperature of 850 ° C. to obtain a decarburized and annealed steel strip. Subsequently, the decarburized annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.023 mass%. Subsequently, the annealing separator which has MgO as a main component was apply | coated, and final annealing was performed. In this way, various samples were prepared.
そして、熱間圧延鋼帯中の析出物と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図７に示す。図７の横軸はＭｎＳｅの析出量をＳｅの量に換算した値（質量％）を示し、縦軸はＢＮの析出量をＢに換算した値（質量％）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。図７に示すように、ＭｎＳｅ及びＢＮの析出量が一定値未満の試料では、磁束密度Ｂ８が低かった。このことは、二次再結晶が不安定であったことを示す。 And the relationship between the precipitates in the hot rolled steel strip and the magnetic properties after finish annealing was investigated. The result is shown in FIG. The horizontal axis of FIG. 7 shows the value (mass%) in which the precipitation amount of MnSe is converted into the amount of Se, and the vertical axis shows the value (mass%) in which the precipitation amount of BN is converted into B. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. As shown in FIG. 7, the magnetic flux density B8 was low in the sample in which the amount of MnSe and BN deposited was less than a certain value. This indicates that secondary recrystallization was unstable.
更に、ＭｎＳｅ及びＢＮが一定量以上析出している試料について、ＢＮとして析出していないＢの量と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図８に示す。図８の横軸はＢ含有量（質量％）を示し、縦軸はＢＮの析出量をＢに換算した値（質量％）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。図８に示すように、ＢＮとして析出していないＢの量が一定値以上である試料では、磁束密度Ｂ８が低かった。このことは、二次再結晶が不安定であったことを示す。 Furthermore, the relationship between the amount of B not precipitated as BN and the magnetic properties after finish annealing was investigated for samples in which a certain amount of MnSe and BN were precipitated. The result is shown in FIG. The horizontal axis of FIG. 8 shows B content (mass%), and a vertical axis | shaft shows the value (mass%) which converted the precipitation amount of BN into B. In FIG. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. As shown in FIG. 8, the magnetic flux density B8 was low in the sample in which the amount of B not precipitated as BN was a certain value or more. This indicates that secondary recrystallization was unstable.
また、熱間圧延の条件と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図９及び図10に示す。 In addition, the relationship between hot rolling conditions and magnetic properties after finish annealing was investigated. The results are shown in FIG. 9 and FIG.
図９の横軸はＭｎ含有量（質量％）を示し、縦軸は熱間圧延時のスラブ加熱の温度（℃）を示す。図10の横軸はＢ含有量（質量％）を示し、縦軸は熱間圧延時のスラブ加熱の温度（℃）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。また、図９中の曲線は、下記（式６）で表わされるＭｎＳｅの溶体化温度Ｔ２（℃）を示し、図10中の曲線は、（式７）で表わされるＢＮの溶体化温度Ｔ３（℃）を示している。図９に示すように、Ｍｎ含有量に応じて定まる温度以下でスラブ加熱を行った試料において、高い磁束密度Ｂ８が得られることが判明した。更に、この温度はＭｎＳｅの溶体化温度Ｔ２とほぼ一致していることも判明した。また、図10に示すように、Ｂ含有量に応じて定まる温度以下でスラブ加熱を行った試料において、高い磁束密度Ｂ８が得られることも判明した。更に、この温度はＢＮの溶体化温度Ｔ３とほぼ一致していることも判明した。つまり、スラブ加熱を、ＭｎＳｅ及びＢＮが完全固溶しない温度域で行うことが有効であることが判明した。 The horizontal axis in FIG. 9 indicates the Mn content (% by mass), and the vertical axis indicates the slab heating temperature (° C.) during hot rolling. The horizontal axis in FIG. 10 indicates the B content (% by mass), and the vertical axis indicates the slab heating temperature (° C.) during hot rolling. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. The curve in FIG. 9 shows the solution temperature T2 (° C.) of MnSe represented by the following (formula 6), and the curve in FIG. 10 shows the solution temperature T3 of BN represented by (formula 7) ( ° C). As shown in FIG. 9, it was found that a high magnetic flux density B8 can be obtained in a sample that has been slab heated at a temperature that is determined according to the Mn content. Furthermore, it was also found that this temperature almost coincided with the solution temperature T2 of MnSe. Further, as shown in FIG. 10, it was also found that a high magnetic flux density B8 can be obtained in a sample subjected to slab heating at a temperature determined according to the B content. Furthermore, it was also found that this temperature almost coincided with the solution temperature T3 of BN. That is, it has been found that it is effective to perform slab heating in a temperature range where MnSe and BN are not completely dissolved.
T2=10733/(4.08-log([Mn]×[Se]))-273 ・・・（式６）
T3=16000/(5.92-log([B]×[N]))-273 ・・・（式７）
ここで、［Ｓｅ］はＳｅ含有量（質量％）を示す。
T2 = 10733 / (4.08-log ([Mn] × [Se]))-273 (Expression 6)
T3 = 16000 / (5.92-log ([B] × [N]))-273 (Expression 7)
Here, [Se] indicates the Se content (% by mass).
更にＢＮの析出挙動を調査した結果、その析出温度域が８００℃〜１０００℃であることが判明した。 Furthermore, as a result of investigating the precipitation behavior of BN, the precipitation temperature range was found to be 800 ° C to 1000 ° C.
また、本発明者らは、熱間圧延の仕上げ圧延の終了温度について調査した。この調査では、先ず、Ｓｉ：３．３質量％、Ｃ：０．０６質量％、酸可溶性Ａｌ：０．０２８質量％、Ｎ：０．００７質量％、Ｍｎ：０．１質量％、Ｓｅ：０．００７質量％、及びＢ：０．００１質量％〜０．００４質量％を含有し、残部がＦｅ及び不可避的不純物からなる種々の珪素鋼スラブを得た。次いで、珪素鋼スラブを１２００℃の温度で加熱し、熱間圧延を行った。熱間圧延では、粗圧延を１０５０℃で行った後、仕上げ圧延を１０２０℃〜９００℃で行って厚さが２．３ｍｍの熱間圧延鋼帯を得た。そして、熱間圧延鋼帯に冷却水を噴射して５５０℃まで冷却し、その後、大気中で冷却した。続いて、熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、１５℃／ｓの速度で冷間圧延鋼帯を加熱し、８５０℃の温度で脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２３質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、仕上げ焼鈍を行った。このようにして種々の試料を作製した。 In addition, the present inventors investigated the end temperature of hot rolling finish rolling. In this investigation, first, Si: 3.3% by mass, C: 0.06% by mass, acid-soluble Al: 0.028% by mass, N: 0.007% by mass, Mn: 0.1% by mass, Se: Various silicon steel slabs containing 0.007% by mass and B: 0.001% by mass to 0.004% by mass with the balance being Fe and inevitable impurities were obtained. Next, the silicon steel slab was heated at a temperature of 1200 ° C. and hot rolled. In hot rolling, after rough rolling was performed at 1050 ° C., finish rolling was performed at 1020 ° C. to 900 ° C. to obtain a hot rolled steel strip having a thickness of 2.3 mm. And it cooled to 550 degreeC by injecting cooling water to a hot-rolled steel strip, and cooled in air | atmosphere after that. Subsequently, the hot rolled steel strip was annealed. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, the cold-rolled steel strip was heated at a rate of 15 ° C./s, and decarburized and annealed at a temperature of 850 ° C. to obtain a decarburized and annealed steel strip. Subsequently, the decarburized annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.023 mass%. Subsequently, the annealing separator which has MgO as a main component was apply | coated, and final annealing was performed. In this way, various samples were prepared.
そして、熱間圧延の仕上げ圧延の終了温度と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図11に示す。図11の横軸はＢ含有量（質量％）を示し、縦軸は仕上げ圧延の終了温度Ｔｆを示す。また、白丸は磁束密度Ｂ８が1.91Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が1.91Ｔ未満であったことを示している。図11に示すように、仕上げ圧延の終了温度Ｔｆが（式１１）を満たしている場合に、高い磁束密度Ｂ８が得られることが判明した。これは、仕上げ圧延の終了温度Ｔｆの制御によって、ＢＮの析出が更に促進されたためであると考えられる。 And the relationship between the finishing temperature of the finish rolling of hot rolling and the magnetic properties after finish annealing was investigated. The result is shown in FIG. In FIG. 11, the horizontal axis indicates the B content (% by mass), and the vertical axis indicates the finish rolling finish temperature Tf. A white circle indicates that the magnetic flux density B8 is 1.91 T or more, and a black square indicates that the magnetic flux density B8 is less than 1.91 T. As shown in FIG. 11, it was found that a high magnetic flux density B8 can be obtained when the finish rolling finish temperature Tf satisfies (Equation 11). This is considered to be because precipitation of BN was further promoted by controlling the finish rolling finish temperature Tf.
さらに析出物と磁性の関係についてSとSeを含む組成を有する珪素鋼素材について調査する試験を行った。鋼成分がＳｉ：３．３質量％、Ｃ：０．０６質量％、酸可溶性Ａｌ：０．０２６質量％、Ｎ：０．００９質量％、Ｍｎ：０．０５質量％〜０．２０質量％、Ｓ：０．００５質量％、Ｓｅ：０．００７質量％、及びＢ：０．００１０質量％〜０．００３５質量％を含有し、残部がＦｅ及び不可避的不純物からなる種々の珪素鋼スラブを得た。次いで、珪素鋼スラブを１１００℃〜１２５０℃の温度で加熱し、熱間圧延を行った。熱間圧延では、粗圧延を１０５０℃で行った後、仕上げ圧延を１０００℃で行って厚さが２．３ｍｍの熱間圧延鋼帯を得た。そして、熱間圧延鋼帯に冷却水を噴射して５５０℃まで冷却し、その後、大気中で冷却した。続いて、熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、１５℃／ｓの速度で冷間圧延鋼帯を加熱し、８５０℃の温度で脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２１質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、仕上げ焼鈍を行った。このようにして種々の試料を作製した。 Furthermore, the test which investigates the silicon steel raw material which has a composition containing S and Se about the relationship between a precipitate and magnetism was done. Steel component is Si: 3.3 mass%, C: 0.06 mass%, acid-soluble Al: 0.026 mass%, N: 0.009 mass%, Mn: 0.05 mass% to 0.20 mass% , S: 0.005 mass%, Se: 0.007 mass%, and B: 0.0010 mass% to 0.0035 mass%, with the balance being various silicon steel slabs composed of Fe and inevitable impurities. Obtained. Next, the silicon steel slab was heated at a temperature of 1100 ° C. to 1250 ° C. to perform hot rolling. In hot rolling, after rough rolling was performed at 1050 ° C., finish rolling was performed at 1000 ° C. to obtain a hot rolled steel strip having a thickness of 2.3 mm. And it cooled to 550 degreeC by injecting cooling water to a hot-rolled steel strip, and cooled in air | atmosphere after that. Subsequently, the hot rolled steel strip was annealed. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, the cold-rolled steel strip was heated at a rate of 15 ° C./s, and decarburized and annealed at a temperature of 850 ° C. to obtain a decarburized and annealed steel strip. Subsequently, the decarburized and annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.021% by mass. Subsequently, the annealing separator which has MgO as a main component was apply | coated, and final annealing was performed. In this way, various samples were prepared.
そして、熱間圧延鋼帯中の析出物と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図12に示す。図12の横軸はＭｎＳの析出量をＳの量に換算した値とＭｎＳｅの析出量をＳｅの量に換算した値に０．５を乗じて得られる値との和（質量％）を示し、縦軸はＢＮの析出量をＢに換算した値（質量％）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。図12に示すように、ＭｎＳ、ＭｎＳｅ及びＢＮの析出量が一定値未満の試料では、磁束密度Ｂ８が低かった。このことは、二次再結晶が不安定であったことを示す。 And the relationship between the precipitates in the hot rolled steel strip and the magnetic properties after finish annealing was investigated. The results are shown in FIG. The horizontal axis of FIG. 12 shows the sum (% by mass) of a value obtained by converting the amount of MnS precipitation into the amount of S and a value obtained by multiplying the value obtained by converting the amount of precipitation of MnSe into the amount of Se by 0.5. The vertical axis indicates the value (mass%) obtained by converting the amount of precipitated BN into B. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. As shown in FIG. 12, the magnetic flux density B8 was low in the sample in which the amount of MnS, MnSe, and BN deposited was less than a certain value. This indicates that secondary recrystallization was unstable.
更に、ＭｎＳ、ＭｎＳｅ及びＢＮが一定量以上析出している試料について、ＢＮとして析出していないＢの量と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図13に示す。図13の横軸はＢ含有量（質量％）を示し、縦軸はＢＮの析出量をＢに換算した値（質量％）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。図13に示すように、ＢＮとして析出していないＢの量が一定値以上である試料では、磁束密度Ｂ８が低かった。このことは、二次再結晶が不安定であったことを示す。 Furthermore, the relationship between the amount of B not precipitated as BN and the magnetic properties after finish annealing was investigated for samples in which MnS, MnSe and BN were precipitated in a certain amount or more. The result is shown in FIG. The horizontal axis of FIG. 13 shows the B content (mass%), and the vertical axis shows the value (mass%) obtained by converting the precipitation amount of BN into B. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. As shown in FIG. 13, the magnetic flux density B8 was low in the sample in which the amount of B not precipitated as BN was a certain value or more. This indicates that secondary recrystallization was unstable.
更に、磁気特性および皮膜密着性が良好な試料について析出物の形態を調査した結果、ＭｎＳ又はＭｎＳｅを核としてＢＮがＭｎＳ又はＭｎＳｅの周辺に複合析出していることが判明した。このような複合析出物は二次再結晶を安定化させるインヒビターとして有効であるとともに、二次再結晶焼鈍中に最適な温度域で分解してグラス皮膜形成時にBを地鉄-皮膜界面に供給し、最終的に皮膜密着性向上に寄与する。 Furthermore, as a result of investigating the form of the precipitate for a sample with good magnetic properties and film adhesion, it was found that BN was precipitated in the vicinity of MnS or MnSe with MnS or MnSe as a nucleus. Such a composite precipitate is effective as an inhibitor to stabilize secondary recrystallization, and decomposes in an optimum temperature range during secondary recrystallization annealing, and supplies B to the ground iron-film interface during glass film formation. Finally, it contributes to improving film adhesion.
次に、熱間圧延の条件と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図14及び図15に示す。 Next, the relationship between hot rolling conditions and magnetic properties after finish annealing was investigated. The results are shown in FIGS. 14 and 15.
図14の横軸はＭｎ含有量（質量％）を示し、縦軸は熱間圧延時のスラブ加熱の温度（℃）を示す。図15の横軸はＢ含有量（質量％）を示し、縦軸は熱間圧延時のスラブ加熱の温度（℃）を示す。また、白丸は磁束密度Ｂ８が１．８８Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．８８Ｔ未満であったことを示している。また、図14中の２つの曲線は、式（式５）で表わされるＭｎＳの溶体化温度Ｔ１（℃）、及び式（式６）で表わされるＭｎＳｅの溶体化温度Ｔ２（℃）を示し、図15中の曲線は、式（式７）で表わされるＢＮの溶体化温度Ｔ３（℃）を示している。図14に示すように、Ｍｎ含有量に応じて定まる温度以下でスラブ加熱を行った試料において、高い磁束密度Ｂ８が得られることが判明した。更に、この温度は、ＭｎＳの溶体化温度Ｔ１及びＭｎＳｅの溶体化温度Ｔ２とほぼ一致していることも判明した。また、図15に示すように、Ｂ含有量に応じて定まる温度以下でスラブ加熱を行った試料において、高い磁束密度Ｂ８が得られることも判明した。更に、この温度はＢＮの溶体化温度Ｔ３とほぼ一致していることも判明した。つまり、スラブ加熱を、ＭｎＳ、ＭｎＳｅ及びＢＮが完全固溶しない温度域で行うことが有効であることが判明した。 The horizontal axis in FIG. 14 indicates the Mn content (% by mass), and the vertical axis indicates the slab heating temperature (° C.) during hot rolling. The horizontal axis in FIG. 15 indicates the B content (% by mass), and the vertical axis indicates the slab heating temperature (° C.) during hot rolling. A white circle indicates that the magnetic flux density B8 is 1.88T or more, and a black square indicates that the magnetic flux density B8 is less than 1.88T. Further, the two curves in FIG. 14 show the solution temperature T1 (° C.) of MnS represented by the formula (formula 5) and the solution temperature T2 (° C.) of MnSe represented by the formula (formula 6). The curve in FIG. 15 shows the solution temperature T3 (° C.) of BN represented by the formula (formula 7). As shown in FIG. 14, it was found that a high magnetic flux density B8 can be obtained in a sample that has been slab heated at a temperature that is determined according to the Mn content. Furthermore, it was also found that this temperature substantially coincided with the solution temperature T1 of MnS and the solution temperature T2 of MnSe. Further, as shown in FIG. 15, it was also found that a high magnetic flux density B8 can be obtained in a sample subjected to slab heating at a temperature that is determined according to the B content. Furthermore, it was also found that this temperature almost coincided with the solution temperature T3 of BN. That is, it has been found that it is effective to perform slab heating in a temperature range where MnS, MnSe and BN are not completely dissolved.
また、本発明者らは、熱間圧延の仕上げ圧延の終了温度について調査した。この調査では、先ず、Ｓｉ：３．３質量％、Ｃ：０．０６質量％、酸可溶性Ａｌ：０．０２６質量％、Ｎ：０．００９質量％、Ｍｎ：０．１質量％、Ｓ：０．００５質量％、Ｓｅ：０．００７質量％、及びＢ：０．００１質量％〜０．００４質量％を含有し、残部がＦｅ及び不可避的不純物からなる種々の珪素鋼スラブを得た。次いで、珪素鋼スラブを１２００℃の温度で加熱し、熱間圧延を行った。熱間圧延では、粗圧延を１０５０℃で行った後、仕上げ圧延を１０２０℃〜９００℃で行って厚さが２．３ｍｍの熱間圧延鋼帯を得た。そして、熱間圧延鋼帯に冷却水を噴射して５５０℃まで冷却し、その後、大気中で冷却した。続いて、熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、１５℃／ｓの速度で冷間圧延鋼帯を加熱し、８５０℃の温度で脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２１質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、仕上げ焼鈍を行った。このようにして種々の試料を作製した。 In addition, the present inventors investigated the end temperature of hot rolling finish rolling. In this investigation, first, Si: 3.3 mass%, C: 0.06 mass%, acid-soluble Al: 0.026 mass%, N: 0.009 mass%, Mn: 0.1 mass%, S: Various silicon steel slabs containing 0.005% by mass, Se: 0.007% by mass, and B: 0.001% by mass to 0.004% by mass with the balance being Fe and inevitable impurities were obtained. Next, the silicon steel slab was heated at a temperature of 1200 ° C. and hot rolled. In hot rolling, after rough rolling was performed at 1050 ° C., finish rolling was performed at 1020 ° C. to 900 ° C. to obtain a hot rolled steel strip having a thickness of 2.3 mm. And it cooled to 550 degreeC by injecting cooling water to a hot-rolled steel strip, and cooled in air | atmosphere after that. Subsequently, the hot rolled steel strip was annealed. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, the cold-rolled steel strip was heated at a rate of 15 ° C./s, and decarburized and annealed at a temperature of 850 ° C. to obtain a decarburized and annealed steel strip. Subsequently, the decarburized and annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.021% by mass. Subsequently, the annealing separator which has MgO as a main component was apply | coated, and final annealing was performed. In this way, various samples were prepared.
そして、熱間圧延の仕上げ圧延の終了温度と仕上げ焼鈍後の磁気特性との関係を調査した。この結果を図16に示す。図16の横軸はＢ含有量（質量％）を示し、縦軸は仕上げ圧延の終了温度Ｔｆを示す。また、白丸は磁束密度Ｂ８が１．91Ｔ以上であったことを示し、黒四角は磁束密度Ｂ８が１．91Ｔ未満であったことを示している。図16に示すように、仕上げ圧延の終了温度Ｔｆが（式１１）を満たしている場合に、高い磁束密度Ｂ８が得られることが判明した。これは、仕上げ圧延の終了温度Ｔｆの制御によって、ＢＮの析出が更に促進されたためであると考えられる。 And the relationship between the finishing temperature of the finish rolling of hot rolling and the magnetic properties after finish annealing was investigated. The result is shown in FIG. The horizontal axis in FIG. 16 indicates the B content (mass%), and the vertical axis indicates the finish rolling finish temperature Tf. A white circle indicates that the magnetic flux density B8 is 1.91 T or more, and a black square indicates that the magnetic flux density B8 is less than 1.91 T. As shown in FIG. 16, it was found that a high magnetic flux density B8 can be obtained when the finish rolling finish temperature Tf satisfies (Equation 11). This is considered to be because precipitation of BN was further promoted by controlling the finish rolling finish temperature Tf.
以上の実験の結果から、ＢＮの析出形態を制御することによって、安定して方向性電磁鋼板の磁気特性が向上することがわかる。ＢがＢＮとしてＭｎＳ又はＭｎＳｅと複合析出しない場合に二次再結晶が不安定になって良好な磁気特性が得られない理由は今のところ明らかになっていないが、次のように考えられる。 From the results of the above experiments, it can be seen that the magnetic properties of the grain-oriented electrical steel sheet are stably improved by controlling the precipitation form of BN. The reason why secondary recrystallization becomes unstable and good magnetic properties cannot be obtained when B does not precipitate together with MnS or MnSe as BN has not been clarified so far, but is considered as follows.
まず磁気特性については次のとおりである。一般的に、固溶状態のＢは粒界に偏析しやすく、熱間圧延後に単独析出したＢＮは微細であることが多い。これらの固溶状態のＢ及び微細なＢＮは、脱炭焼鈍が行われる低温度域では強力なインヒビターとして一次再結晶時に粒成長を抑制し、仕上げ焼鈍が行われる高温度域では局所的にインヒビターとして機能しなくなり、鋼の結晶粒組織が混粒組織となる。したがって、一次再結晶温度が低温度域では一次再結晶粒が小さいので、方向性電磁鋼板の磁束密度が低くなってしまう。また、高温度域では結晶粒組織が混粒組織となるため、二次再結晶が不安定になる。 First, the magnetic characteristics are as follows. In general, B in a solid solution state is easily segregated at grain boundaries, and BN that is single-deposited after hot rolling is often fine. These solid solution B and fine BN suppress the grain growth at the time of primary recrystallization as a strong inhibitor in a low temperature range where decarburization annealing is performed, and locally inhibit in a high temperature range where finish annealing is performed. And the steel grain structure becomes a mixed grain structure. Therefore, since the primary recrystallized grains are small when the primary recrystallization temperature is low, the magnetic flux density of the grain-oriented electrical steel sheet becomes low. In addition, since the crystal grain structure becomes a mixed grain structure in a high temperature range, secondary recrystallization becomes unstable.
次に本発明の各条件について限定理由を以下に説明する。 Next, the reasons for limitation for each condition of the present invention will be described below.
前述のように、磁気特性が良好な試料の析出物の形態は、MnSを核としてBNがMnSの周辺に複合析出しているものであった。このようなBNは比較的大きな析出物となる傾向がある。このような析出状態においてBについてQV分析すると、いわゆるinsol Bに起因するトリガーピークが多数検出される。QVのトリガーピークをPSA解析を行うと、insol Bの面積が大きいものほどMnSと複合析出したBNが多い結果となった。以上の検討から、QV-PSA分析でinsol Bが一定量以上存在すると、最終製品の磁気特性が良好であるとの結果が得られた。すなわち（１）式のように、Sinsol BをQV-PSA分析のinsol Bの面積とした場合、
Sinsol B≧5%・・・・・・・・・・（式１）
であると良い結果が得られる。（式１）式の左辺が10%以上であると、更によい磁気特性が得られ、B8が1.9T以上を安定的に得られる効果がある。一方5%を下回ると、二次再結晶が不安定化して良好な磁気特性が得られなくなる。
（式１）式の値を得るには、以下の方法による。
まず試料は表層部をベルダー研磨して清浄化した後、発光分光分析法を用いて、放電により得られる特定成分の発光強度を順に並び替えたパルス強度順位図を作成して、金属中特定成分の全量、不溶成分量、固溶成分量を下式により求める。
Insol.成分量測定値 ＝ 全積分値−理想Total面積＝ S3 ＝ ｛Sall−N×F(N/2)｝…（式２）
Total量測定値 ＝ 理想Total曲線とX軸間の面積＝ 2×(S1 + S2) ＝ N×F(N/2)…（式３）
Sinsol B= （Insol.成分量測定値/ Total量測定値）×100…（式４）
ここで、Ｎは放電により得られた全パルス数から発光不良データを除いたパルス数であり、Ｓallは発光パルス強度x=1からNまでの全積分値であり、Ｆ（Ｎ／２）はパルス強度順に並び替えた時、中間順位値となる強度値であり、ｙ＝Ｆ（ｘ）はｘ＝１からＮ／２までのパルス強度値を表現する関数である。なお、この方法は特許文献１によるものである。
As described above, the form of the precipitate of the sample having good magnetic properties was that BN was complexly precipitated around MnS with MnS as a nucleus. Such BN tends to be a relatively large precipitate. When QV analysis is performed on B in such a precipitated state, many trigger peaks caused by so-called insol B are detected. When the PSA analysis was performed on the trigger peak of QV, the larger the insol B area, the more BN was precipitated in a complex with MnS. From the above study, it was found that the magnetic properties of the final product are good when a certain amount of insol B is present in the QV-PSA analysis. That is, as shown in equation (1), when S insol B is the area of insol B in the QV-PSA analysis,
S insol B ≧ 5% (Formula 1)
Good results can be obtained. When the left side of the formula (1) is 10% or more, better magnetic characteristics are obtained, and there is an effect that B8 can be stably obtained at 1.9 T or more. On the other hand, below 5%, secondary recrystallization becomes unstable and good magnetic properties cannot be obtained.
In order to obtain the value of equation (1), the following method is used.
First of all, the sample was cleaned by bellder polishing the surface layer, and using a light emission spectroscopic analysis method, a pulse intensity ranking diagram in which the light emission intensities of specific components obtained by discharge were rearranged in order was created. The total amount, the insoluble component amount, and the solid solution component amount are obtained from the following formula.
Insol. Component amount measurement value = total integral value−ideal total area = S3 = {Sall−N × F (N / 2)} (Formula 2)
Total amount measured value = Area between ideal Total curve and X axis = 2 x (S1 + S2) = N x F (N / 2) ... (Formula 3)
S insol B = (Insol. Component amount measurement value / Total amount measurement value) × 100 (Equation 4)
Here, N is the number of pulses obtained by removing light emission failure data from the total number of pulses obtained by discharge, Sall is the total integrated value from light emission pulse intensity x = 1 to N, and F (N / 2) is When rearranged in order of pulse intensity, the intensity value is an intermediate rank value, and y = F (x) is a function expressing the pulse intensity values from x = 1 to N / 2. This method is based on
本発明においてはNは全パルス数で2000パルスとした。F(x)はパルス強度順にソートした発光強度曲線で、N番目のパルスに対する発光強度を示す。本解析法の基本原理を図17に示す。 In the present invention, N is 2000 pulses in total. F (x) is an emission intensity curve sorted in order of pulse intensity, and indicates the emission intensity for the Nth pulse. The basic principle of this analysis method is shown in FIG.
次に成分範囲の限定理由について述べる。 Next, the reason for limiting the component range will be described.
本実施形態で用いる珪素鋼素材は、Ｓｉ：０．８質量％〜７質量％、酸可溶性Ａｌ：０．０１質量％〜０．０６５質量％、Ｎ：０．００４質量％〜０．０１２質量％、Ｍｎ：０．０５質量％〜１質量％、Ｓ及びＳｅ：総量で０．００３質量％〜０．０１５質量％、並びにＢ：０．０００５質量％〜０．００８０質量％を含有し、Ｃ含有量が０．０８５質量％以下であり、残部がＦｅ及び不可避的不純物からなる。 The silicon steel material used in the present embodiment is Si: 0.8 mass% to 7 mass%, acid-soluble Al: 0.01 mass% to 0.065 mass%, N: 0.004 mass% to 0.012 mass% %, Mn: 0.05% by mass to 1% by mass, S and Se: 0.003% by mass to 0.015% by mass in total, and B: 0.0005% by mass to 0.0080% by mass, C content is 0.085 mass% or less, and the remainder consists of Fe and inevitable impurities.
Ｓｉは、電気抵抗を高めて鉄損を低下させる。しかし、Ｓｉ含有量が７質量％を超えていると、冷間圧延が極めて困難となり、冷間圧延時に割れが生じやすくなる。このため、Ｓｉ含有量は７質量％以下とし、４．５質量％以下であることが好ましく、４質量％以下であることが更に好ましい。また、Ｓｉ含有量が０．８質量％未満であると、仕上げ焼鈍時にγ変態が生じ、方向性電磁鋼板の結晶方位が損なわれてしまう。このため、Ｓｉ含有量は０．８質量％以上とし、２質量％以上であることが好ましく、２．５質量％以上であることが更に好ましい。 Si increases electric resistance and decreases iron loss. However, if the Si content exceeds 7% by mass, cold rolling becomes extremely difficult, and cracks are likely to occur during cold rolling. For this reason, Si content shall be 7 mass% or less, it is preferable that it is 4.5 mass% or less, and it is still more preferable that it is 4 mass% or less. On the other hand, if the Si content is less than 0.8% by mass, γ transformation occurs during finish annealing, and the crystal orientation of the grain-oriented electrical steel sheet is impaired. For this reason, Si content shall be 0.8 mass% or more, it is preferable that it is 2 mass% or more, and it is still more preferable that it is 2.5 mass% or more.
Ｃは、一次再結晶組織を制御に有効な元素であるが、磁気特性に悪影響を及ぼす。このため、本実施形態では、仕上げ焼鈍前に脱炭焼鈍を行う。しかし、Ｃ含有量が０．０８５質量％を超えていると、脱炭焼鈍にかかる時間が長くなり、工業生産における生産性が損なわれてしまう。このため、Ｃ含有量は０．８５質量％以下とし、０．０７質量％以下であることが好ましい。 C is an element effective for controlling the primary recrystallization structure, but adversely affects the magnetic properties. For this reason, in this embodiment, decarburization annealing is performed before finish annealing. However, if the C content exceeds 0.085% by mass, the time required for decarburization annealing becomes long, and the productivity in industrial production is impaired. For this reason, C content shall be 0.85 mass% or less, and it is preferable that it is 0.07 mass% or less.
酸可溶性Ａｌは、Ｎと結合して（Ａｌ、Ｓｉ）Ｎとして析出し、インヒビターとして機能する。酸可溶性Ａｌの含有量が０．０１質量％〜０．０６５質量％の範囲内にある場合に二次再結晶が安定する。このため、酸可溶性Ａｌの含有量は０．０１質量％以上０．０６５質量％以下とする。また、酸可溶性Ａｌの含有量は０．０２質量％以上であることが好ましく、０．０２５質量％以上であることが更に好ましい。また、酸可溶性Ａｌの含有量は０．０４質量％以下であることが好ましく、０．０３質量％以下であることが更に好ましい。 Acid-soluble Al binds to N and precipitates as (Al, Si) N and functions as an inhibitor. Secondary recrystallization is stabilized when the content of acid-soluble Al is in the range of 0.01 mass% to 0.065 mass%. For this reason, content of acid-soluble Al shall be 0.01 mass% or more and 0.065 mass% or less. Moreover, it is preferable that content of acid-soluble Al is 0.02 mass% or more, and it is still more preferable that it is 0.025 mass% or more. Moreover, it is preferable that content of acid-soluble Al is 0.04 mass% or less, and it is still more preferable that it is 0.03 mass% or less.
ＢはＮと結合してＢＮとしてＭｎＳ又はＭｎＳｅと複合析出し、インヒビターとして機能する。Ｂ含有量が０．０００５質量％〜０．００８０質量％の範囲内にある場合に二次再結晶が安定する。このため、Ｂ含有量は０．０００５質量％以上０．００８０質量％以下とする。また、Ｂ含有量は０．００１％以上であることが好ましく、０．００１５％以上であることが更に好ましい。また、Ｂ含有量は０．００４０％以下であることが好ましく、０．００３０％以下であることが更に好ましい。 B binds to N and precipitates together with MnS or MnSe as BN and functions as an inhibitor. Secondary recrystallization is stabilized when the B content is in the range of 0.0005 mass% to 0.0080 mass%. For this reason, B content shall be 0.0005 mass% or more and 0.0080 mass% or less. Further, the B content is preferably 0.001% or more, and more preferably 0.0015% or more. Further, the B content is preferably 0.0040% or less, and more preferably 0.0030% or less.
Ｎは、Ｂ又はＡｌと結合してインヒビターとして機能する。Ｎ含有量が０．００４質量％未満であると、十分な量のインヒビターを得ることができない。このため、Ｎ含有量は０．００４質量％以上とし、０．００６質量％以上であることが好ましく、０．００７質量％以上であることが更に好ましい。一方、Ｎ含有量が０．０１２質量％を超えていると、冷間圧延時に鋼帯中にブリスターとよばれる空孔が生じる。このため、Ｎ含有量は０．０１２質量％以下とし、０．０１０質量％以下であることが好ましく、０．００９質量％以下であることが更に好ましい。 N binds to B or Al and functions as an inhibitor. When the N content is less than 0.004% by mass, a sufficient amount of inhibitor cannot be obtained. For this reason, N content shall be 0.004 mass% or more, it is preferable that it is 0.006 mass% or more, and it is still more preferable that it is 0.007 mass% or more. On the other hand, when the N content exceeds 0.012% by mass, pores called blisters are generated in the steel strip during cold rolling. For this reason, N content shall be 0.012 mass% or less, it is preferable that it is 0.010 mass% or less, and it is still more preferable that it is 0.009 mass% or less.
Ｍｎ、Ｓ及びＳｅは、ＢＮが複合析出する核となるＭｎＳ及びＭｎＳｅを生成し、複合析出物がインヒビターとして機能する。Ｍｎ含有量が０．０５質量％〜１質量％の範囲内にある場合に二次再結晶が安定する。このため、Ｍｎ含有量は０．０５質量％以上１質量％以下とする。また、Ｍｎ含有量は０．０８質量％以上であることが好ましく、０．０９質量％以上であることが更に好ましい。また、Ｍｎ含有量は０．５０質量％以下であることが好ましく、０．２質量％以下であることが更に好ましい。 Mn, S, and Se generate MnS and MnSe, which are nuclei from which BN is compositely precipitated, and the composite precipitate functions as an inhibitor. Secondary recrystallization is stabilized when the Mn content is in the range of 0.05 mass% to 1 mass%. For this reason, Mn content shall be 0.05 mass% or more and 1 mass% or less. Moreover, it is preferable that Mn content is 0.08 mass% or more, and it is still more preferable that it is 0.09 mass% or more. The Mn content is preferably 0.50% by mass or less, and more preferably 0.2% by mass or less.
また、Ｓ及びＳｅの含有量が総量で０．００３質量％〜０．０１５質量％の範囲内にある場合に二次再結晶が安定する。このため、Ｓ及びＳｅの含有量は総量で０．００３質量％以上０．０１５質量％以下とする。また、熱間圧延における割れの発生を防止する観点から、下記式（９）が満たされることが好ましい。なお、Ｓ又はＳｅのいずれかのみが珪素鋼素材に含有されていてもよく、Ｓ及びＳｅの双方が含有されていてもよい。Ｓ及びＳｅの双方が含有されている場合、ＢＮの析出をより安定的に促進し、磁気特性を安定的に向上させることができる。 In addition, secondary recrystallization is stabilized when the total content of S and Se is in the range of 0.003% to 0.015% by mass. For this reason, content of S and Se shall be 0.003 mass% or more and 0.015 mass% or less in total amount. Moreover, it is preferable that following formula (9) is satisfy | filled from a viewpoint which prevents generation | occurrence | production of the crack in hot rolling. In addition, only S or Se may be contained in the silicon steel material, and both S and Se may be contained. When both S and Se are contained, the precipitation of BN can be more stably promoted, and the magnetic properties can be stably improved.
[Mn]/([S]+[Se])≧4 ・・・（９）
Ｔｉは、粗大なＴｉＮを形成して、インヒビターとして機能するＢＮ及び（Ａｌ，Ｓｉ）Ｎの析出量に影響を及ぼす。Ｔｉ含有量が０．００４質量％を超えていると、良好な磁気特性を得にくい。このため、Ｔｉ含有量は０．００４質量％以下であることが好ましい。
[Mn] / ([S] + [Se]) ≧ 4 (9)
Ti forms coarse TiN and affects the amount of precipitation of BN and (Al, Si) N that function as inhibitors. When the Ti content exceeds 0.004% by mass, it is difficult to obtain good magnetic properties. For this reason, it is preferable that Ti content is 0.004 mass% or less.
珪素鋼素材に、更に、Ｃｒ、Ｃｕ、Ｎｉ、Ｐ、Ｍｏ、Ｓｎ、Ｓｂ、及びＢｉからなる群から選択された一種以上が下記の範囲で含有されていてもよい。 The silicon steel material may further contain one or more selected from the group consisting of Cr, Cu, Ni, P, Mo, Sn, Sb, and Bi within the following range.
Ｃｒは、脱炭焼鈍時に形成される酸化層を改善し、グラス皮膜の形成に有効である。しかし、Ｃｒ含有量が０．３質量％を超えていると、脱炭が著しく阻害される。このため、Ｃｒ含有量は０．３質量％以下とする。 Cr improves the oxide layer formed at the time of decarburization annealing, and is effective for forming a glass film. However, if the Cr content exceeds 0.3% by mass, decarburization is significantly inhibited. For this reason, Cr content shall be 0.3 mass% or less.
Ｃｕは、比抵抗を高めて鉄損を低減させる。しかし、Ｃｕ含有量が０．４質量％を超えるとこの効果が飽和する。また、熱間圧延時に「カッパーヘゲ」とよばれる表面疵が生じることもある。このため、Ｃｕ含有量は０．４質量％以下とした。 Cu increases specific resistance and reduces iron loss. However, this effect is saturated when the Cu content exceeds 0.4% by mass. In addition, surface flaws called “copper hege” may occur during hot rolling. For this reason, Cu content was 0.4 mass% or less.
Ｎｉは、比抵抗を高めて鉄損を低減させる。また、Ｎｉは、熱間圧延鋼帯の金属組織を制御して磁気特性を向上させる。しかし、Ｎｉ含有量が１質量％を超えていると、二次再結晶が不安定になる。このため、Ｎｉ含有量は１質量％以下とする。 Ni increases the specific resistance and reduces the iron loss. Ni also improves the magnetic properties by controlling the metal structure of the hot-rolled steel strip. However, when the Ni content exceeds 1% by mass, secondary recrystallization becomes unstable. For this reason, Ni content shall be 1 mass% or less.
Ｐは、比抵抗を高めて鉄損を低減させる。しかし、Ｐ含有量が０．５質量％を超えていると、圧延性に問題が生じる。このため、Ｐ含有量は０．５質量％以下とする。 P increases specific resistance and reduces iron loss. However, if the P content exceeds 0.5% by mass, a problem arises in rollability. For this reason, P content shall be 0.5 mass% or less.
Ｍｏは、熱間圧延時の表面性状を改善する。しかし、Ｍｏ含有量が０．１質量％を超えるとこの効果が飽和してしまう。このため、Ｍｏ含有量は０．１質量％以下とする。 Mo improves the surface properties during hot rolling. However, when the Mo content exceeds 0.1% by mass, this effect is saturated. For this reason, Mo content shall be 0.1 mass% or less.
Ｓｎ及びＳｂは、粒界偏析元素である。本実施形態で用いられる珪素鋼素材はＡｌを含有しているため、仕上げ焼鈍の条件によっては焼鈍分離剤から放出される水分によりＡｌが酸化される場合がある。この場合、方向性電磁鋼板内の部位によってインヒビター強度にばらつきが生じ、磁気特性もばらつくことがある。しかし、粒界偏析元素が含有されている場合には、Ａｌの酸化を抑制することができる。つまり、Ｓｎ及びＳｂは、Ａｌの酸化を抑制して磁気特性のばらつきを抑制する。但し、Ｓｎ及びＳｂの含有量が総量で０．３０質量％を超えていると、脱炭焼鈍時に酸化層が形成されにくくなり、グラス皮膜の形成が不十分となる。また、脱炭が著しく阻害される。このため、Ｓｎ及びＳｂの含有量は総量で０．３質量％以下とする。 Sn and Sb are grain boundary segregation elements. Since the silicon steel material used in this embodiment contains Al, Al may be oxidized by moisture released from the annealing separator depending on the conditions of finish annealing. In this case, the inhibitor strength varies depending on the site in the grain-oriented electrical steel sheet, and the magnetic characteristics may vary. However, when a grain boundary segregating element is contained, oxidation of Al can be suppressed. That is, Sn and Sb suppress the variation in magnetic characteristics by suppressing the oxidation of Al. However, if the total content of Sn and Sb exceeds 0.30% by mass, an oxide layer is hardly formed at the time of decarburization annealing, and the formation of the glass film becomes insufficient. Moreover, decarburization is significantly inhibited. For this reason, content of Sn and Sb shall be 0.3 mass% or less in total amount.
Ｂｉは、硫化物等の析出物を安定化してインヒビターとしての機能を強化する。しかし、Ｂｉ含有量が０．０１質量％を超えていると、グラス皮膜の形成に悪影響が及ぶ。このため、Ｂｉ含有量は０．０１質量％以下とする。 Bi stabilizes precipitates such as sulfides and strengthens the function as an inhibitor. However, if the Bi content exceeds 0.01% by mass, the glass film formation is adversely affected. For this reason, Bi content shall be 0.01 mass% or less.
次に、本実施形態における各処理について説明する。 Next, each process in the present embodiment will be described.
上記の成分の珪素鋼素材（スラブ）は、例えば、転炉又は電気炉等により鋼を溶製し、必要に応じて溶鋼を真空脱ガス処理し、次いで、連続鋳造を行うことによって作製することができる。また、連続鋳造に代えて、造塊後分塊圧延を行っても作製することができる。珪素鋼スラブの厚さは、例えば１５０ｍｍ〜３５０ｍｍとし、２２０ｍｍ〜２８０ｍｍとすることが好ましい。また、厚さが３０ｍｍ〜７０ｍｍの所謂薄スラブを作製してもよい。薄スラブを作製した場合は、熱間圧延鋼帯を得る際の粗圧延を省略することができる。 The silicon steel material (slab) of the above components is manufactured by, for example, melting steel with a converter or an electric furnace, vacuum degassing the molten steel as necessary, and then performing continuous casting. Can do. Moreover, it can replace with continuous casting and can also produce even if it performs after-agglomeration partial rolling. The thickness of the silicon steel slab is, for example, 150 mm to 350 mm, and preferably 220 mm to 280 mm. Moreover, you may produce what is called a thin slab whose thickness is 30 mm-70 mm. When a thin slab is produced, rough rolling when obtaining a hot-rolled steel strip can be omitted.
珪素鋼スラブの作製後には、スラブ加熱を行い、熱間圧延を行う。そして、本実施形態では、ＢＮをＭｎＳ及び／又はＭｎＳｅと複合析出させ、熱間圧延鋼帯におけるＢＮ、ＭｎＳ、及びＭｎＳｅの析出量が下記（式８）〜（式１０）を満たすように、スラブ加熱及び熱間圧延の条件を設定する。 After the production of the silicon steel slab, slab heating is performed and hot rolling is performed. And in this embodiment, BN is complex-precipitated with MnS and / or MnSe, and the precipitation amount of BN, MnS, and MnSe in the hot rolled steel strip satisfies the following (formula 8) to (formula 10): Set conditions for slab heating and hot rolling.
ＢａｓＢＮ≧０．０００５ ・・・（式８）
［Ｂ］−ＢａｓＢＮ≦０．００１ ・・・（式９）
ＳａｓＭｎＳ＋０．５×ＳｅａｓＭｎＳｅ≧０．００２ ・・・（式１０）
ここで、「ＢａｓＢＮ」はＢＮとして析出したＢの量（質量％）を示し、「ＳａｓＭｎＳ」はＭｎＳとして析出したＳの量（質量％）を示し、「ＳｅａｓＭｎＳｅ」はＭｎＳｅとして析出したＳｅの量（質量％）を示している。
B asBN ≧ 0.0005 (Expression 8)
[B] −B asBN ≦ 0.001 (Formula 9)
S asMnS + 0.5 × Se asMnSe ≧ 0.002 (Formula 10)
Here, “B asBN ” indicates the amount (mass%) of B precipitated as BN, “S asMnS ” indicates the amount (mass%) of S precipitated as MnS, and “Se asMnSe ” precipitates as MnSe. The amount (% by mass) of Se is shown.
Ｂについては、（式８）及び（式９）が満たされるように、その析出量及び固溶量を制御する。インヒビターの量を確保するために、一定量以上のＢＮを析出させておく。また、固溶しているＢの量が多い場合、その後の工程で不安定な微細析出物を形成して一次再結晶組織に悪影響を及ぼすことがある。 About B, the precipitation amount and the amount of solid solution are controlled so that (Formula 8) and (Formula 9) may be satisfy | filled. In order to ensure the amount of the inhibitor, a certain amount or more of BN is precipitated. In addition, when the amount of dissolved B is large, unstable fine precipitates may be formed in the subsequent process, which may adversely affect the primary recrystallization structure.
ＭｎＳ及びＭｎＳｅは、ＢＮが複合析出する核として機能する。従って、ＢＮを十分に析出させて磁気特性を向上させるために、（式１０）が満たされるように、その析出量を制御する。 MnS and MnSe function as nuclei in which BN is compositely precipitated. Therefore, in order to sufficiently precipitate BN and improve the magnetic characteristics, the amount of precipitation is controlled so that (Equation 10) is satisfied.
（式９）に表わされる条件は、図３、図８、及び図13から導き出したものである。図３、図８、及び図13から、［Ｂ］−ＢａｓＢＮが０．００１質量％以下の場合に、磁束密度Ｂ８が１．８８Ｔ以上の良好な磁束密度が得られることがわかる。 The conditions expressed in (Equation 9) are derived from FIGS. 3, 8, and 13. From FIG. 3, FIG. 8, and FIG. 13, it can be seen that when [B] -B asBN is 0.001 mass% or less, a good magnetic flux density with a magnetic flux density B8 of 1.88 T or more can be obtained.
式（式８）及び（式９）に表わされる条件は、図２、図７、及び図12から導き出したものである。図２からＢａｓＢＮが０．０００５質量％以上、かつＳａｓＭｎＳが０．００２質量％以上の場合に、磁束密度Ｂ８が１．８８Ｔ以上の良好な磁束密度が得られることがわかる。 The conditions expressed in the equations (Equation 8) and (Equation 9) are derived from FIG. 2, FIG. 7, and FIG. FIG. 2 shows that when B asBN is 0.0005 mass% or more and S asMnS is 0.002 mass% or more, a good magnetic flux density with a magnetic flux density B8 of 1.88 T or more can be obtained.
同様に、図７からＢａｓＢＮが０．０００５質量％以上、かつＳｅａｓＭｎＳｅが０．００４質量％以上の場合に、磁束密度Ｂ８が１．８８Ｔ以上の良好な磁束密度が得られることがわかる。同様に、図12からＢａｓＢＮが０．０００５質量％以上、かつＳｅａｓＭｎＳｅ＋０．５×ＳｅａｓＭｎＳｅが０．００２質量％以上の場合に、磁束密度Ｂ８が１．８８Ｔ以上の良好な磁束密度が得られることがわかる。そして、ＳａｓＭｎＳが０．００２質量％以上であれば、必然的に、ＳｅａｓＭｎＳｅ＋０．５×ＳｅａｓＭｎＳｅは０．００２質量％以上となり、ＳｅａｓＭｎＳｅが０．００４質量％以上であれば、必然的に、ＳｅａｓＭｎＳｅ＋０．５×ＳｅａｓＭｎＳｅは０．００２質量％以上となる。従って、ＳｅａｓＭｎＳｅ＋０．５×ＳｅａｓＭｎＳｅが０．００２質量％以上であることが重要である。 Similarly, it can be seen from FIG. 7 that when B asBN is 0.0005 mass% or more and Se asMnSe is 0.004 mass% or more, a favorable magnetic flux density with a magnetic flux density B8 of 1.88 T or more can be obtained. Similarly, from FIG. 12, when B asBN is 0.0005 mass% or more and Se asMnSe + 0.5 × Se asMnSe is 0.002 mass% or more, the magnetic flux density B8 is 1.88 T or more. It turns out that it is obtained. And if S asMnS is 0.002% by mass or more, Se asMnSe + 0.5 × Se asMnSe is necessarily 0.002% by mass or more, and if Se asMnSe is 0.004% by mass or more, inevitably. Therefore , Se asMnSe + 0.5 × Se asMnSe is 0.002% by mass or more. Therefore, it is important that Se asMnSe + 0.5 × Se asMnSe is 0.002 mass% or more.
また、スラブ加熱の温度は、以下の条件を満たすように設定する。 The slab heating temperature is set so as to satisfy the following conditions.
（ｉ）記珪素鋼素材にＳ及びＳｅが含有されている場合
下記（式５）で表される温度Ｔ１（℃）以下、下記（式６）で表される温度Ｔ２（℃）以下、かつ下記（式７）で表わされる温度Ｔ３（℃）以下
（ii）前記珪素鋼素材にＳｅが含有されていない場合
下記（式５）で表される温度Ｔ１（℃）以下、かつ下記（式７）で表わされる温度Ｔ３（℃）以下、
（iii ）珪素鋼素材にＳが含有されていない場合
下記（式６）で表される温度Ｔ２（℃）以下、かつ下記（式７）で表わされる温度Ｔ３（℃）以下、
T1=14855/(6.82-log([Mn]×[S]))-273 ・・・（式５）
T2=10733/(4.08-log([Mn]×[Se]))-273 ・・・（式６）
T3=16000/(5.92-log([B]×[N]))-273 ・・・（式７）
このような温度でスラブ加熱を行うと、スラブ加熱時にはＢＮ、ＭｎＳ及びＭｎＳｅが完全には固溶せず、熱間圧延中にＢＮ、ＭｎＳ及びＭｎＳｅの析出が促進されるからである。図４、図９、及び図14からわかるように、溶体化温度Ｔ１及びＴ２は、１．８８Ｔ以上の磁束密度Ｂ８が得られるスラブ加熱温度の上限とほぼ一致している。また、図５、図10、及び図15からわかるように、溶体化温度Ｔ３は、１．８８Ｔ以上の磁束密度Ｂ８が得られるスラブ加熱温度の上限とほぼ一致している。
(I) When the silicon steel material contains S and Se, the temperature T1 (° C.) or less represented by the following (formula 5), the temperature T2 (° C.) or less represented by the following (formula 6), and The temperature T3 (° C.) or less represented by the following (formula 7) (ii) When Se is not contained in the silicon steel material The temperature T1 (° C.) or less represented by the following (formula 5) and the following (formula 7) ) Or lower temperature T3 (° C.)
(Iii) When S is not contained in the silicon steel material, the temperature T2 (° C.) or less represented by the following (formula 6) and the temperature T3 (° C.) or less represented by the following (formula 7),
T1 = 14855 / (6.82-log ([Mn] × [S]))-273 (Expression 5)
T2 = 10733 / (4.08-log ([Mn] × [Se]))-273 (Expression 6)
T3 = 16000 / (5.92-log ([B] × [N]))-273 (Expression 7)
When slab heating is performed at such a temperature, BN, MnS and MnSe are not completely dissolved during slab heating, and precipitation of BN, MnS and MnSe is promoted during hot rolling. As can be seen from FIGS. 4, 9, and 14, the solution temperatures T1 and T2 substantially coincide with the upper limit of the slab heating temperature at which a magnetic flux density B8 of 1.88 T or more is obtained. Further, as can be seen from FIGS. 5, 10, and 15, the solution temperature T3 substantially coincides with the upper limit of the slab heating temperature at which the magnetic flux density B8 of 1.88 T or more is obtained.
また、スラブ加熱の温度を以下の条件も満たすように設定することが更に好ましい。スラブ加熱中に、好ましい量のＭｎＳ又はＭｎＳｅを析出させるためである。 Further, it is more preferable to set the slab heating temperature so as to satisfy the following conditions. This is because a preferable amount of MnS or MnSe is precipitated during slab heating.
（i）珪素鋼スラブにＳｅが含有されていない場合
下記（式１２）で表される温度Ｔ４（℃）以下
（ii）珪素鋼スラブにＳが含有されていない場合
下記（式１３）で表される温度Ｔ５（℃）以下
T4=14855/(6.82-log([Mn-0.0034]×[S-0.002]))-273 ・・・（式１２）
T5=10733/(4.08-log([Mn-0.0034]×[Se-0.004]))-273 ・・・（式１３）
スラブ加熱の温度が高すぎる場合、ＢＮ、ＭｎＳ及び／又はＭｎＳｅが完全に固溶することがある。この場合、熱間圧延時に、ＢＮ、ＭｎＳ及び／又はＭｎＳｅを析出させることが困難になる。従って、スラブ加熱は、温度Ｔ１及び／又は温度Ｔ２以下、かつ温度Ｔ３以下で行うことが好ましい。更に、スラブ加熱の温度が温度Ｔ４又はＴ５以下であると、好ましい量のＭｎＳ又はＭｎＳｅがスラブ加熱中に析出するため、これらの周辺にＢＮを複合析出させて、容易に有効なインヒビターを形成することが可能となる。
(I) When Se is not contained in the silicon steel slab Temperature T4 (° C.) or less expressed by the following (Formula 12) (ii) When S is not contained in the silicon steel slab Expressed by the following (Formula 13) Temperature T5 (℃) or less
T4 = 14855 / (6.82-log ([Mn-0.0034] × [S-0.002]))-273 (Equation 12)
T5 = 10733 / (4.08-log ([Mn-0.0034] × [Se-0.004]))-273 (Equation 13)
When the temperature of slab heating is too high, BN, MnS and / or MnSe may be completely dissolved. In this case, it becomes difficult to precipitate BN, MnS and / or MnSe during hot rolling. Accordingly, the slab heating is preferably performed at a temperature T1 and / or a temperature T2 or lower and a temperature T3 or lower. Further, when the temperature of the slab heating is equal to or lower than the temperature T4 or T5, a preferable amount of MnS or MnSe precipitates during the slab heating, so that BN is complex-deposited around these to easily form an effective inhibitor. It becomes possible.
また、Ｂに関し、熱間圧延での仕上げ圧延の終了温度Ｔｆを下記（式１１）が満たされるように設定する。ＢＮの析出を促進するためである。 Regarding B, the finishing temperature Tf of the finish rolling in the hot rolling is set so that the following (Formula 11) is satisfied. This is to promote the precipitation of BN.
Ｔｆ≦１０００−１００００ｘ［Ｂ］ ・・・（式１１）
図６、図11、図16からわかるように、式（式１１）が示す条件は、1.91Ｔ以上の磁束密度Ｂ８が得られる条件とほぼ一致している。また、仕上げ圧延の終了温度Ｔｆは、ＢＮの析出の観点から８００℃以上とすることが好ましい。
Tf ≦ 1000−10000 × [B] (Formula 11)
As can be seen from FIGS. 6, 11, and 16, the condition indicated by the expression (Expression 11) substantially coincides with the condition for obtaining the magnetic flux density B8 of 1.91 T or more. Moreover, it is preferable that the finishing temperature Tf of finish rolling shall be 800 degreeC or more from a viewpoint of precipitation of BN.
熱間圧延後には、熱間圧延鋼帯の焼鈍を行う。次いで、冷間圧延を行う。上記のように、冷間圧延は１回のみ行ってもよく、複数回の冷間圧延を、間に中間焼鈍を行いながら行ってもよい。冷間圧延では、最終冷間圧延率を８０％以上とすることが好ましい。これは、良好な一次再結晶集合組織を発達させるためである。 After hot rolling, the hot rolled steel strip is annealed. Next, cold rolling is performed. As described above, the cold rolling may be performed only once, or multiple times of cold rolling may be performed while performing intermediate annealing. In cold rolling, the final cold rolling rate is preferably 80% or more. This is to develop a good primary recrystallization texture.
その後、脱炭焼鈍を行う。この結果、鋼帯に含まれるＣが除去される。脱炭焼鈍は、例えば、湿潤雰囲気中で行う。また、例えば、７７０℃〜９５０℃の温度域で一次再結晶により得られる結晶粒径が１５μｍ以上となるような時間で行うことが好ましい。これは、良好な磁気特性を得るためである。続いて、焼鈍分離剤の塗布及び仕上げ焼鈍を行う。この結果、二次再結晶により｛１１０｝＜００１＞方位を向く結晶粒が優先的に成長する。 Thereafter, decarburization annealing is performed. As a result, C contained in the steel strip is removed. Decarburization annealing is performed in a humid atmosphere, for example. Further, for example, it is preferable to carry out in a time such that the crystal grain size obtained by primary recrystallization is 15 μm or more in a temperature range of 770 ° C. to 950 ° C. This is to obtain good magnetic properties. Subsequently, application of an annealing separator and finish annealing are performed. As a result, crystal grains oriented in the {110} <001> orientation are preferentially grown by secondary recrystallization.
また、脱炭焼鈍の開始から仕上げ焼鈍における二次再結晶の発現までの間に、窒化処理を行っておく。これは、（Ａｌ，Ｓｉ）Ｎのインヒビターを形成するためである。この窒化処理は、脱炭焼鈍中に行ってもよく、仕上げ焼鈍中に行ってもよい。脱炭焼鈍中に行う場合、例えばアンモニア等の窒化能のあるガスを含有する雰囲気中で焼鈍を行えばよい。また、連続焼鈍炉の加熱帯又は均熱帯のいずれで窒化処理を行ってもよく、また、均熱帯よりも後の段階で窒化処理を行ってもよい。仕上げ焼鈍中に窒化処理を行う場合、例えばＭｎＮ等の窒化能のある粉末を焼鈍分離剤中に添加すればよい。 In addition, nitriding is performed between the start of decarburization annealing and the occurrence of secondary recrystallization in finish annealing. This is to form an inhibitor of (Al, Si) N. This nitriding treatment may be performed during decarburization annealing or may be performed during finish annealing. When performing during decarburization annealing, annealing may be performed in an atmosphere containing a gas having nitriding ability such as ammonia. Further, the nitriding treatment may be performed either in the heating zone of the continuous annealing furnace or in the soaking zone, and the nitriding treatment may be performed in a stage after the soaking zone. When nitriding is performed during finish annealing, for example, powder having nitriding ability such as MnN may be added to the annealing separator.
仕上げ焼鈍の方法も特に限定するものではない。但し、本実施形態では、ＢＮによりインヒビターが強化されているので、仕上げ焼鈍の加熱過程において、１０００℃〜１１００℃の温度範囲内での加熱速度を１５℃／ｈ以下とすることが好ましい。また、加熱速度の制御に代えて、１０００℃〜１１００℃の温度範囲内に１０時間以上保持する恒温焼鈍を行うことも有効である。 The method of finish annealing is not particularly limited. However, in this embodiment, since the inhibitor is strengthened by BN, it is preferable to set the heating rate in the temperature range of 1000 ° C. to 1100 ° C. to 15 ° C./h or less in the heating process of finish annealing. Further, instead of controlling the heating rate, it is also effective to perform constant temperature annealing that is held in a temperature range of 1000 ° C. to 1100 ° C. for 10 hours or more.
このような本実施形態によれば、安定して優れた磁気特性の方向性電磁鋼板を製造することができる。 According to this embodiment, a grain-oriented electrical steel sheet having excellent magnetic properties can be manufactured stably.
次に、本発明者らが行った実験について説明する。これらの実験における条件等は、本発明の実施可能性及び効果を確認するために採用した例であり、本発明は、これらの例に限定されるものではない。
＜実施例１＞
表１にあるような組成を有し、残部はFeおよび不可避的不純物からなるスラブを作製した。次いで、スラブを１１００℃で加熱し、その後、９００℃で仕上げ圧延を行った。1100℃は、表１の組成から計算されるT1、T2、T3の値の全てを下回る値である。このようにして厚さが２．３ｍｍの熱間圧延鋼帯を得た。続いて、１１００℃で熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、８３０℃の湿潤雰囲気ガス中で１００秒間、脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２３質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、１５℃／ｈの速度で１２００℃まで加熱して仕上げ焼鈍を行った。
Next, experiments conducted by the present inventors will be described. The conditions in these experiments are examples adopted for confirming the feasibility and effects of the present invention, and the present invention is not limited to these examples.
<Example 1>
A slab having a composition as shown in Table 1, with the balance being Fe and inevitable impurities was prepared. Next, the slab was heated at 1100 ° C., and then finish rolled at 900 ° C. 1100 ° C. is a value lower than all of the values of T1, T2, and T3 calculated from the composition in Table 1. Thus, a hot rolled steel strip having a thickness of 2.3 mm was obtained. Subsequently, the hot rolled steel strip was annealed at 1100 ° C. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, decarburization annealing was performed in a humid atmosphere gas at 830 ° C. for 100 seconds to obtain a decarburized annealing steel strip. Subsequently, the decarburized annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.023 mass%. Next, an annealing separator containing MgO as a main component was applied, and finish annealing was performed by heating to 1200 ° C. at a rate of 15 ° C./h.
このようにして得られた鋼板は表２ある組成を有していた。このような仕上げ焼鈍後の試料について、磁気特性（磁束密度Ｂ８）を測定した。磁気特性（磁束密度Ｂ８）は、ＪＩＳ Ｃ２５５６に準じて測定した。また、QV-PSA解析により、Sinsol Bの値を得た。 The steel sheet thus obtained had the composition shown in Table 2. The magnetic properties (magnetic flux density B8) of the sample after such finish annealing were measured. The magnetic properties (magnetic flux density B8) were measured according to JIS C2556. Moreover, the value of Sinsol B was obtained by QV-PSA analysis.
表２および表３に示すように、本発明の範囲の組成の鋼板であり、QV-PSA解析によるSinsol Bが5%以上である場合に磁束密度が良好であることがわかる。
＜実施例２＞
表4にある組成を有し、残部がＦｅ及び不可避的不純物からなるスラブを作製した。さらに表５にある温度条件でスラブ加熱と仕上げ圧延を行い、厚さが２．３ｍｍの熱間圧延鋼帯を得た。このような熱処理を経た熱延板のB、BN、MnSおよびMnSeの分析結果は表６の通りであった。続いて、１１００℃で熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、８３０℃の湿潤雰囲気ガス中で１００秒間、脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２３質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、１５℃／ｈの速度で１２００℃まで加熱して仕上げ焼鈍を行った。そして実施例1と同様にして、磁気特性（磁束密度Ｂ８）を測定した。この結果を表７に示す。
As shown in Table 2 and Table 3, it is a steel plate having a composition within the range of the present invention, and it is understood that the magnetic flux density is good when S insol B is 5% or more by QV-PSA analysis.
<Example 2>
A slab having the composition shown in Table 4 with the balance being Fe and inevitable impurities was produced. Furthermore, slab heating and finish rolling were performed under the temperature conditions shown in Table 5 to obtain a hot-rolled steel strip having a thickness of 2.3 mm. Table 6 shows the analysis results of B, BN, MnS and MnSe of the hot-rolled sheet subjected to such heat treatment. Subsequently, the hot rolled steel strip was annealed at 1100 ° C. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, decarburization annealing was performed in a humid atmosphere gas at 830 ° C. for 100 seconds to obtain a decarburized annealing steel strip. Subsequently, the decarburized annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.023 mass%. Next, an annealing separator containing MgO as a main component was applied, and finish annealing was performed by heating to 1200 ° C. at a rate of 15 ° C./h. Then, in the same manner as in Example 1, the magnetic characteristics (magnetic flux density B8) were measured. The results are shown in Table 7.
表７に示すように、スラブ加熱温度がT1、T2、T3より高い場合、あるいは熱間圧延での仕上げ圧延の終了温度Ｔｆが高すぎる場合と低すぎる場合には磁束密度が低かった。一方、スラブ加熱温度が温度Ｔ１、T2およびT3の全て以下の場合には、良好な磁束密度が得られた。 As shown in Table 7, the magnetic flux density was low when the slab heating temperature was higher than T1, T2, and T3, or when the finish rolling finish temperature Tf in hot rolling was too high and too low. On the other hand, when the slab heating temperature was below all of the temperatures T1, T2 and T3, a good magnetic flux density was obtained.
以上から明らかなように、本発明の範囲の操業条件によれば、良好な磁気特性を有する方向性電磁鋼板を得ることができる。
＜実施例３＞
表８にある組成を有し、残部がＦｅ及び不可避的不純物からなるスラブを作製した。次いで、表９にある条件でスラブを加熱した後に900℃で仕上げ圧延を行った。このようにして厚さが２．３ｍｍの熱間圧延鋼帯を得た。続いて、１１００℃で熱間圧延鋼帯の焼鈍を行った。次いで、冷間圧延を行って厚さが０．２２ｍｍの冷間圧延鋼帯を得た。その後、８３０℃の湿潤雰囲気ガス中で１００秒間、脱炭焼鈍を行って脱炭焼鈍鋼帯を得た。続いて、脱炭焼鈍鋼帯をアンモニア含有雰囲気中で焼鈍して鋼帯中の窒素を０．０２２質量％まで増加させた。次いで、ＭｇＯを主成分とする焼鈍分離剤を塗布し、１５℃／ｈの速度で１２００℃まで加熱して仕上げ焼鈍を行った。そして、実施例１と同様にして、磁気特性（磁束密度Ｂ８）を測定した。この結果を表１０に示す。
As is apparent from the above, according to the operating conditions within the scope of the present invention, a grain-oriented electrical steel sheet having good magnetic properties can be obtained.
<Example 3>
A slab having the composition shown in Table 8 with the balance being Fe and inevitable impurities was produced. Next, after the slab was heated under the conditions shown in Table 9, finish rolling was performed at 900 ° C. Thus, a hot rolled steel strip having a thickness of 2.3 mm was obtained. Subsequently, the hot rolled steel strip was annealed at 1100 ° C. Next, cold rolling was performed to obtain a cold rolled steel strip having a thickness of 0.22 mm. Thereafter, decarburization annealing was performed in a humid atmosphere gas at 830 ° C. for 100 seconds to obtain a decarburized annealing steel strip. Subsequently, the decarburized and annealed steel strip was annealed in an ammonia-containing atmosphere to increase the nitrogen in the steel strip to 0.022% by mass. Next, an annealing separator containing MgO as a main component was applied, and finish annealing was performed by heating to 1200 ° C. at a rate of 15 ° C./h. Then, the magnetic characteristics (magnetic flux density B8) were measured in the same manner as in Example 1. The results are shown in Table 10.
表８および表１０より明らかなように、素材の組成が本発明の範囲を外れた比較例では皮磁束密度が低かった。しかし、素材の組成が本発明の範囲にある発明例では、良好な磁束密度が得られた。 As is apparent from Tables 8 and 10, the skin magnetic flux density was low in the comparative example in which the composition of the material was outside the scope of the present invention. However, in the invention examples in which the composition of the material is within the scope of the present invention, a good magnetic flux density was obtained.
本発明は、例えば、電磁鋼板製造産業及び電磁鋼板利用産業において利用することができる。 The present invention can be used in, for example, an electromagnetic steel sheet manufacturing industry and an electromagnetic steel sheet utilization industry.
Claims (3)
SInsol B≧5%・・・・(1)
であることを特徴とする熱延鋼板。
ただし、SInsol Bは、発光分光分析法を用いて、放電により得られる特定成分の発光強度を順に並べ替えたパルス強度順位図を作成して、下記（２）、（３）及び（４）式により得られる値である。
Insol.成分量測定値 ＝｛Sall−N×F(N/2)｝…（２）
Total量測定値 ＝ N×F(N/2)…（３）
Sinsol B= （Insol.成分量測定値/ Total量測定値）×100…（４）
ここで、Ｎは放電により得られた全パルス数から発光不良データを除いたパルス数であり、Ｓallは発光パルス強度x=1からNまでの全積分値であり、Ｆ（Ｎ／２）は、パルス強度順に並び替えた時、中間順位値となる強度値であり、ｙ＝Ｆ（ｘ）はｘ＝１からＮ／２までのパルス強度値を表現する関数である。 From the group consisting of S and Se, containing 0.8 to 7% Si, 0.01 to 0.065% acid-soluble Al, 0.004 to 0.012% N, 0.05 to 1% Mn, 0.0005 to 0.0080% B, in mass%. In the electrical steel sheet material comprising at least one selected at a total amount of 0.003 to 0.015%, a C content of 0.085% or less, and the balance being Fe and inevitable impurities,
S Insol B ≧ 5% ・ ・ ・ ・ (1)
A hot-rolled steel sheet characterized by
However, S Insol B uses emission spectroscopic analysis to create a pulse intensity ranking diagram in which the emission intensities of specific components obtained by discharge are rearranged in order, and the following (2), (3) and (4) It is a value obtained by the formula.
Insol. Measured component amount = {Sall-N x F (N / 2)} (2)
Total amount measured value = N x F (N / 2) ... (3)
S insol B = (Insol. Component amount measurement value / Total amount measurement value) × 100 (4)
Here, N is the number of pulses obtained by removing light emission failure data from the total number of pulses obtained by discharge, Sall is the total integrated value from light emission pulse intensity x = 1 to N, and F (N / 2) is The intensity values are intermediate rank values when rearranged in order of pulse intensity, and y = F (x) is a function expressing the pulse intensity values from x = 1 to N / 2.
加熱された前記珪素鋼素材の熱間圧延を行って熱間圧延鋼帯を得る工程と、
前記熱間圧延鋼帯の焼鈍を行って、焼鈍鋼帯を得る工程と、
前記焼鈍鋼帯を１回以上、冷間圧延して冷間圧延鋼帯を得る工程と、
前記冷間圧延鋼帯の脱炭焼鈍を行って、一次再結晶が生じた脱炭焼鈍鋼帯を得る工程と、
ＭｇＯを主成分とする焼鈍分離剤を前記脱炭焼鈍鋼帯に塗布する工程と、
前記脱炭焼鈍鋼帯の仕上げ焼鈍により、二次再結晶を生じさせる工程と、
を有し、
更に、前記脱炭焼鈍の開始から仕上げ焼鈍における二次再結晶の発現までの間に、前記脱炭焼鈍鋼帯のＮ含有量を増加させる窒化処理を行う工程を有し、
前記所定の温度は、
前記珪素鋼素材にＳ及びＳｅが含有されている場合、下記(式５)で表される温度Ｔ１（℃）以下、下記(式６)で表される温度Ｔ２（℃）以下、かつ下記(式７)で表わされる温度Ｔ３（℃）以下であり、
前記珪素鋼素材にＳｅが含有されていない場合、下記(式５)で表される温度Ｔ１（℃）以下、かつ下記(式７)で表わされる温度Ｔ３（℃）以下であり、
前記珪素鋼素材にＳが含有されていない場合、下記(式６)で表される温度Ｔ２（℃）以下、かつ下記(式７)で表わされる温度Ｔ３（℃）以下であり、
前記熱間圧延鋼帯中のＢＮ、ＭｎＳ及びＭｎＳｅの量は下記(式８)、(式９)及び(式１０)を満たすことを特徴とする（１）または（２）に記載の方向性電磁鋼板の製造方法。
T1=14855/(6.82-log([Mn]×[S]))-273 ・・・(式５)
T2=10733/(4.08-log([Mn]×[Se]))-273 ・・・(式６)
T3=16000/(5.92-log([B]×[N]))-273 ・・・(式７)
BasBN≧0.0005 ・・・(式８)
[B]―BasBN≦0.001 ・・・(式９)
SasMnS+0.5×SeasMnSe≧0.002 ・・・(式１０)
ここで、［Ｍｎ］は前記珪素鋼素材のＭｎ含有量（質量％）を示し、［Ｓ］は前記珪素鋼素材のＳ含有量（質量％）を示し、［Ｓｅ］は前記珪素鋼素材のＳｅ含有量（質量％）を示し、［Ｂ］は前記珪素鋼素材のＢ含有量（質量ｐｐｍ）を示し、［Ｎ］は前記珪素鋼素材のＮ含有量（質量ｐｐｍ）を示し、ＢａｓＢＮは前記熱間圧延鋼帯中にＢＮとして析出しているＢの量（質量％）を示し、ＳａｓＭｎＳは前記熱間圧延鋼帯中にＭｎＳとして析出しているＳの量（質量％）を示し、ＳｅａｓＭｎＳｅは前記熱間圧延鋼帯中にＭｎＳｅとして析出しているＳｅの量（質量％）を示す。 From the group consisting of S and Se, containing 0.8 to 7% Si, 0.01 to 0.065% acid-soluble Al, 0.004 to 0.012% N, 0.05 to 1% Mn, 0.0005 to 0.0080% B, in mass%. A step of heating a magnetic steel sheet material having a total content of 0.003 to 0.015%, a C content of 0.085% or less, and the balance of Fe and unavoidable impurities at a predetermined temperature;
Performing a hot rolling of the heated silicon steel material to obtain a hot rolled steel strip; and
Annealing the hot rolled steel strip to obtain an annealed steel strip; and
Cold-rolling the annealed steel strip at least once to obtain a cold-rolled steel strip; and
Performing decarburization annealing of the cold-rolled steel strip to obtain a decarburized annealed steel strip in which primary recrystallization has occurred; and
Applying an annealing separator mainly composed of MgO to the decarburized annealing steel strip;
A step of producing secondary recrystallization by finish annealing of the decarburized annealed steel strip;
Have
Furthermore, between the start of the decarburization annealing and the expression of secondary recrystallization in the finish annealing, there is a step of performing a nitriding treatment to increase the N content of the decarburized annealing steel strip,
The predetermined temperature is
When S and Se are contained in the silicon steel material, the temperature T1 (° C.) or less represented by the following (formula 5), the temperature T2 (° C.) or less represented by the following (formula 6), and the following ( It is below the temperature T3 (° C.) represented by the equation (7),
When Se is not contained in the silicon steel material, the temperature T1 (° C.) or less represented by the following (formula 5) and the temperature T3 (° C.) or less represented by the following (formula 7),
When the silicon steel material does not contain S, the temperature T2 (° C.) or less represented by the following (formula 6) and the temperature T3 (° C.) or less represented by the following (formula 7),
The directionality according to (1) or (2), wherein the amount of BN, MnS and MnSe in the hot-rolled steel strip satisfies the following (Formula 8), (Formula 9) and (Formula 10): A method for producing electrical steel sheets.
T1 = 14855 / (6.82-log ([Mn] × [S]))-273 (Expression 5)
T2 = 10733 / (4.08-log ([Mn] × [Se]))-273 (Expression 6)
T3 = 16000 / (5.92-log ([B] × [N]))-273 (Expression 7)
B asBN ≧ 0.0005 (Equation 8)
[B] -B asBN ≦ 0.001 (Equation 9)
S asMnS + 0.5 × Se asMnSe ≧ 0.002 (Equation 10)
Here, [Mn] represents the Mn content (mass%) of the silicon steel material, [S] represents the S content (mass%) of the silicon steel material, and [Se] represents the silicon steel material. Se content (mass%) is indicated, [B] indicates the B content (mass ppm) of the silicon steel material, [N] indicates the N content (mass ppm) of the silicon steel material, and B asBN Indicates the amount (mass%) of B precipitated as BN in the hot-rolled steel strip, and S asMnS indicates the amount (mass%) of S precipitated as MnS in the hot-rolled steel strip. Se asMnSe indicates the amount (mass%) of Se precipitated as MnSe in the hot-rolled steel strip.
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| WO2020149344A1 (en) * | 2019-01-16 | 2020-07-23 | 日本製鉄株式会社 | Grain-oriented electromagnetic steel sheet having no forsterite film and exhibiting excellent insulating film adhesion |
| RU2771766C1 (en) * | 2019-01-16 | 2022-05-11 | Ниппон Стил Корпорейшн | Grain-oriented electrical steel sheet having excellent insulating coating adhesion without forsterite coating |
| US11466338B2 (en) | 2018-01-25 | 2022-10-11 | Nippon Steel Corporation | Grain oriented electrical steel sheet |
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