JP4192332B2 - Manufacturing method of unidirectional electrical steel sheet - Google Patents

Description

【００２９】
同表に示したとおり、(5 20 70）付近の極大方位は、工程条件によって大きくシフトする。表１では、(5 20 70）に最も近い極大方位と(5 20 70）の方位差が小さい順にａ〜ｖの記号を付した。
製品の磁気特性を良好にするためには、(5 20 70）付近の極大方位を(5 20 70) に近づけることが重要であり、同表からも明らかなように、製品でＢ₈ ≧1.85（Ｔ）を得るためには、(5 20 70）から10°以内に極大方位が存在することが必要不可欠である。
【００３０】
上述したとおり、(5 20 70）から10°以内に極大方位が存在すれば、製品の磁気特性は良好になるが、併せて(90 60 45)付近の極大方位を(90 60 45)に近づけることにより、磁気特性はさらに安定して良好になる。
(90 60 45)付近の極大方位は(5 20 70）に比べるとピークの位置が変化しにくいという特徴をもつが、この方位ピークの微妙な制御が重要であり、(90 60 45)から５°以内に制御することが磁気特性の安定に有効である。
【００３１】
表１の結果を、(5 20 70）付近の極大方位の位置と製品の磁束密度の関係として整理すると、図１のようになる。
【００３２】
なお、本発明では、(5 20 70）方位、(90 60 45)方位が極大方位であるか否かが重要であり、その集積度については特に限定しない。また、他に強いピークが存在するか否かについても限定しない。
【００３３】
従来から注目されてきた｛１１１｝＜１１２＞と｛４１１｝＜１４８＞はいずれも、ゴス方位とΣ９の対応方位関係の範囲内(Brandonの条件）であるが、本発明で対象とする(5 20 70）、(90 60 45)はゴス方位とΣ９の対応方位関係の範囲ではない。
(5 20 70）は｛４１１｝＜１４８＞と12.4°の方位差を有しており、従来の集合組織制御技術では全く考慮が払われていなかった方位である。
また、(90 60 45)は、ミラー指数表示では｛５５４｝＜２２５＞に近く、ＢＣＣ金属多結晶材の一次再結晶集合組織としては比較的頻繁に発生する方位として知られている（鉄鋼薄板の再結晶及び集合組織；昭和49年鉄鋼基礎共同研究会再結晶部会）が、一方向性電磁鋼板の一次再結晶集合組織としては、これまでゴス方位との対応方位関係という観点から｛１１１｝＜１１２＞により注目が集められてきた。
しかしながら、本発明により、ゴス方位の二次再結晶と対応方位関係とは無関係であり、｛１１１｝＜１１２＞ではなくて(90 60 45)に注目すべきことが明らかになった。
【００３４】
一次再結晶焼鈍板の集合組織を制御する方法としては、材料成分、スラブ加熱条件、熱間圧延条件、熱延板焼鈍条件、中間焼鈍条件、冷間圧延条件（特に圧下率と圧延温度および時効処理条件）および一次再結晶焼鈍条件等の調整が挙げられる。
従来技術では｛１１１｝＜１１２＞と｛４１１｝＜１４８＞に強く集積していた一次再結晶焼鈍板の集合組織を、（5 20 70)、(90 60 45)に強く集積させるための具体的な方法として、例えば以下のような方法がある。
【００３５】
方法１：スラブに含有させるインヒビター成分を従来レベルよりも大幅に低減することによって、最終冷延前の粒径を大きくし、粒内からの再結晶を促進させる方法。
粒内からの再結晶を促進させることにより、(5 20 70）方位の再結晶が頻繁になると共に、｛１１１｝＜１１２＞（３次元表示では(90 54.7 45)）に集積していたピークが(90 60 45)の方向にシフトする。
【００３６】
方法２：圧延温度を上げること（温間圧延）により、＜１１０＞方向が圧延方向に揃ったバンド組織からの(5 20 70) 方位再結晶を促進させる方法。
特に、タンデム圧延機での温間圧延は効果的である。
【００３７】
方法３：素材成分（特にインヒビター成分）に応じて最終冷延庄下率を調整する方法。
これは、素材成分が異なると一次再結晶集合組織の集積のピークがシフトする性質と、圧下率が異なると一次再結晶集合組織の集積のピークがシフトする性質を組み合わせて利用する方法である。
【００３８】
本発明では、上記したように、一次再結晶焼鈍板の集合組織を制御することが重要である。制御する方法は特に限定されるものではないが、一般には、以下の製造条件に従うことが望ましい。
【００３９】
まず、素材の成分組成範囲について説明する。
Ｃ：0.005 wt％以上、0.08wt％以下
Ｃは、組織を改善し、二次再結晶を安定化させるために必要な元素で、そのためには0.005wt％以上含有させる必要がある。しかしながら、 0.08wt％を超えると冷延時の破断が増加するだけでなく、脱炭に要する焼鈍時間が長くなり生産性の劣化を招くので、0.08wt％以下とする必要がある。
【００４０】
Si：2.0 wt％以上、4.5 wt％以下
Siは、電気抵抗を増加させ鉄損を低減するために不可欠の元素であり、このためには2.0 wt％以上含有させる必要があるが、4.5 wt％を超えると加工性が劣化し、製造や製品の加工が極めて困難になるので、2.0 wt％以上、4.5 wt％以下の範囲で含有させる必要がある。
【００４１】
Mn：0.03wt％以上、2.5 wt％以下
Mnも、同じく電気抵抗を高め、また製造時の熱間加工性を向上させるのに有用な元素である。この目的のためには、0.03wt％以上の含有が必要であるが、2.5 wt％を超えて含有した場合、 γ変態を誘起して磁気特性が劣化するので、0.03wtwt％以上、2.5 wt％以下の範囲とする必要がある。
【００４２】
インヒビター成分
Al, Se, Ｓ, SbおよびSn等を必要に応じて添加し、インヒビターとして機能させる。その場合におけるこれらの元素の添加量はそれぞれ Al：0.003 〜0.050 wt％, Se：0.003 〜0.050 wt％，Ｓ：0.003 〜0.050 wt％，Sb：0.001 〜0.3 wt％，Sn：0.001 〜0.3 wt％とする必要がある。
【００４３】
Alは、Ｎと結びついてAIＮとしてインヒビターの役割を果たす。インヒビターとして有効に機能させるためには、熱延前のスラブ加熱時に固溶させ、後の工捏で微細に析出させることが必要であるが、含有量が 0.050wt％を超えるとスラブ加熱時の固溶が不完全になり、一方 0.003wt％未満ではインヒビターの量が不足し効果を発揮できないので、 0.003〜0.050 wt％の範囲で含有させる必要がある。
【００４４】
Se、Ｓは、Mnと結びついてMnSe、 MnＳとしてインヒビターの役割を果たす。インヒビターとして有効に機能させるためには、Alと同様、熱延前のスラブ加熱時に固溶させ、後の工程で微細に析出させる必要があるが、含有量が 0.050wt％を超えるとスラブ加熱時の固溶が不完全になり、一方 0.003wt％未満ではインヒビターの量が不足し効果が発揮できないので、 0.003〜0.050 wt％の範囲で含有させる必要がある。
【００４５】
Sb、Snは、粒界に偏析してインヒビターとして機能する。インヒビターとして十分機能させるためには、0.001wt％以上の含有が必要であるが、0.3wt％を超えると製品のベンド特性等の機械的特性が劣化するので、0.001〜0.3 wt％の範囲で含有させる必要がある。
【００４６】
インヒビターとしては、上記元素の他に、Cr, Cu, Nb, Ｂ等を添加することもできる。添加量は、インヒビター機能を十分発揮でき、かつ製品のベンド特性等の機械的特性を劣化させない範囲内とすべきであり、それぞれCr：0.001 〜0.3 wt％, Cu：0.005 〜0.5 wt％, Nb：0.OOl 〜0.3 wt％, Ｂ：0.0001〜0.05wt％とする必要がある。
なお、最近、インヒビター元素を特に添加しなくても、粒界移動度の方位差依存性を利用して二次再結晶を生じさせる技術が報告されているが、この技術は、本発明にも適応できる技術である。
【００４７】
次に、製造工程について説明する。
熱間圧延工程
上記の成分組成に調整されたスラブは、通常の方法に従い、スラブ加熱に供した後、熱間圧延により熱延コイルとする。
なお、近年、スラブ加熱を行わず、連続鋳造後、直接熱間圧延を行う方法が提案されているが、この方法は本発明にも適用することができる。
【００４８】
熱延板焼鈍工程
熱延コイルに、必要に応じて、組織の均一化とインヒビターの微細析出のために、 800〜1150℃の温度範囲で熱延板焼鈍を施す。
【００４９】
冷間圧延・中間焼鈍工程
熱延コイルあるいは熱延板焼鈍後の鋼板に、１回または中間焼鈍を挟む２回以上の冷間圧延を施し、製品板厚とする。冷間圧延は、タンデム圧延機で行ってもゼンジミア圧延機で行ってもよい。また、圧延温度は常温で行ってもよいし、必要に応じて常温よりも高い温度とし、圧延中の動的歪時効やパス間の静的歪み時効を利用して集合組織を制御するも可能である。
【００５０】
脱炭および一次再結晶焼鈍工程
製品板厚に圧延された鋼板に、脱炭と一次再結晶を目的とした焼鈍を施す。
【００５１】
かくして得られる一次再結晶焼鈍板は、一方向性電磁鋼板を製造するための中間材として用いられる。
一般的には、焼鈍分離剤を塗布し、仕上焼鈍を施したのち、必要に応じて絶縁コーティングを塗布・焼き付け、さらに平坦化焼鈍を施すことによって製品となる。
【００５２】
【実施例】
実施例１
Ｃ：0.045 wt％、Si：3.25wt％、Mn：0.08wt％、Al：0.005 wt％、Ｎ：0.004 wt％、Ｓ：0.002 wt％、Se：0.001 wt％、Cu：0.01wt％およびSb：0.010 wt％を含有し、残部はFeおよび不可避不純物からなるスラブを複数用意し、1200℃に加熱後、熱間圧延して 2.5mm厚の熱延コイルとした。次に、熱延コイルに熱延板焼鈍を施し、酸洗したのち、0.34mmの厚みまでタンデム圧延機で１回で冷間圧延した。この際、熱延板焼鈍温度を 800〜1150℃の範囲で、また冷間圧延温度を80〜300 ℃の範囲で変化させた。その後、脱脂処理を行い、 800〜880 ℃で 120秒間の脱炭を兼ねた一次再結晶焼鈍を施した。
かくして、表２に番号１〜20で示すような、集合組織を大きく変化させた一次再結晶焼鈍板が得られた。
また、これらの一次再結晶焼鈍板の一部を採取し、表層付近の集合組織の測定を行った。集合組織は、Ｘ線極点図により測定し、測定データから３次元集合組織を計算により求めた。３次元集合組織はφ₁ 、Φ、φ₂ いずれも５°刻みで求めた。
【００５３】
ついで、これらの一次再結晶焼鈍板に、焼鈍分離剤を塗布してから、最終仕上焼鈍を施した。最終仕上げ焼鈍後、未反応分離剤を除去したのち、コロイタルシリカを含有するリン酸マグネシウムを主成分とする絶縁コーティングを塗布し、800 ℃で焼き付けて製品とした。
各製品から、圧延方向に沿ってエプスタインサイズの試験片を切り出し、磁束密度Ｂ₈ を測定した。
表２に、一次再結晶焼鈍板の集合組織における極大方位と製品の磁束密度Ｂ₈ を示す。
【００５４】
【表２】

【００５５】
同表に示したとおり、本発明に従う一次再結晶焼鈍板を用いて製品を製造した場合には、磁束密度が極めて良好な製品を得ることができた。
【００５６】
実施例２
Ｃ：0.070 wt％、Si：3.25wt％、Mn：0.08wt％、Al：0.025 wt％、Ｎ：0.009 wt％、Ｓ：0.002 wt％、Se：0.020 wt％、Cu：0.10wt％、Sb：0.020 wt％およびSn：0.12wt％を含有し、残部はFeおよび不可避不純物からなるスラブを複数用意し、1400℃に加熱後、熱間圧延して 2.5mm厚の熱延コイルとした。引き続き 800〜1150℃の温度で60秒間保持する熱延板焼鈍を施した。その後、酸洗し、1.7 mmの厚みまでタンデム圧延機により常温で第１回目の冷間圧廷を施したのち、950 ℃の温度で中間焼鈍を施し、再び酸洗したのち、0.22mmの厚みまでゼンジミア圧延機で第２回目の冷間圧延を施した。第２回目の冷間圧延では、圧延温度を80〜300 ℃の範囲で変化させた。ついで、脱脂処理後、 800〜880 ℃で120 秒間の脱炭を兼ねた一次再結晶焼鈍を施した。
かくして、表３に記号ア〜ヌで示すような、集合組織を大きく変化させた一次再結晶焼鈍板が得られた。
また、これらの一次再結晶焼鈍板の一部を採取し、表層付近の集合組織の測定を行った。集合組織は、Ｘ線極点図により測定し、測定データから３次元集合組織を計算により求めた。３次元集合組織はφ₁ 、Φ、φ₂ いずれも５°刻みで求めた。
【００５７】
ついで、これらの一次再結晶焼鈍板に、焼鈍分離剤を塗布してから、最終仕上焼鈍を施した。最終仕上げ焼鈍後、未反応分離剤を除去したのち、コロイダルシリカを含有するリン酸マグネシウムを主成分とする絶縁コーティングを塗布し、800 ℃で焼き付け製品とした。
各製品から、圧延方向に沿ってエプスタインサイズの試験片を切り出し、磁束密度Ｂ₈ を測定した。
表３に、一次再結晶焼鈍板の集合組織における極大方位と製品の磁束密度Ｂ₈ を示す。
【００５８】
【表３】

【００５９】
同表に示したとおり、本発明に従う一次再結晶焼鈍板を用いてた得られた一方向性電磁鋼板は、いずれも良好な磁束密度が得られている。
【００６０】
実施例３
Ｃ：0.040 wt％、Si：2.90wt％、Mn：0.08wt％、Al：0.003 wt％、Ｎ：0.003 wt％、Ｓ：0.001 wt％、Se：0.020 wt％、Cu：0.01wt％、Sb：0.020 wt％を含有し、残部はFeおよび不可避不純物からなるスラブを複数用意し、1200℃に加熱後、熱間圧延して 2.8mm厚の熱延コイルとした。その後、酸洗し、タンデム圧延機により常温で第１回目の冷間圧延を施した。第１回目の冷間圧延後の板厚（中間厚）は、0.50〜2.0 mmの範囲で変化させた。ついで、 900℃〜1100℃の温度で中間焼鈍を施したのち、再び酸洗し、ゼンジミア圧延機により0.22mmの厚みまでの第２回目の冷間圧延を施した。第２回目の冷間圧延では、圧延温度を80〜300 ℃の範囲で変化させた。その後、脱脂処理を行い、 850℃で120 秒間の脱炭を兼ねた一次再結晶焼鈍を施した。
かくして、表４に記号あ〜なで示すような、集合組織を大きく変化させた一次再結晶焼鈍板が得られた。
また、これらの一次再結晶焼鈍板の一部を採取し、表層付近の集合組織の測定を行った。集合組織は、Ｘ線極点図により測定し＜測定データから３次元集合組織を計算により求めた。３次元集合組織はφ₁ 、Φ、φ₂ いずれも５°刻みで求めた。
【００６１】
ついで、これらの一次再結晶焼鈍板に、焼鈍分離剤を塗布してから、最終仕上焼鈍を施した。最終仕上げ焼鈍後、末反応分離剤を除去したのち、コロイタルシリカを含有するリン酸マグネシウムを主成分とする絶縁コーティングを塗布し、800 ℃で焼き付け製品とした。
各製品から、圧延方向に沿ってエプスタインサイズの試験片を切り出し、磁束密度Ｂ₈ を測定した。
表４に、一次再結晶焼鈍板の集合組織における極大方位と製品の磁束密度Ｂ₈ を示す。
【００６２】
【表４】

【００６３】
同表に示したとおり、本発明の一次再結晶焼鈍板を用いることにより、製品の磁束密度が良好となった。
【００６４】
【発明の効果】
かくして、この発明に従い、一次再結晶焼鈍板の集合組織を的確に制御することにより、磁気特性を良好に保った方向性電磁鋼板を安定して製造することが可能となった。
【図面の簡単な説明】
【図１】 一次再結晶集合組織における(5 20 70）付近の極大方位の位置と製品の磁束密度との関係を示した図である。[0001]
[Industrial application fields]
  The present invention stably manufactures a grain-oriented electrical steel sheet with good magnetic properties.MethodIt is about.
[0002]
[Prior art]
Oriented silicon steel sheets are mainly used as iron core materials for transformers and other electrical equipment, and it is basically important that they have excellent magnetic properties such as magnetic flux density and iron loss value. Therefore, after the slab having a thickness of 100 to 300 mm is heated to a high temperature and then hot-rolled, this hot-rolled sheet is made into a final sheet thickness by one or more cold rollings sandwiching intermediate annealing. A complicated process is employed in which primary recrystallization annealing also serves as decarburization, and then an annealing separator is applied, followed by final finishing annealing for the purpose of secondary recrystallization and purification.
In order to enhance the magnetic characteristics, it is possible to grow {110} <001> -oriented grains in which the <001> axis, which is the easy axis of magnetization, is aligned in the rolling direction by secondary recrystallization in the final finish annealing step. is important.
[0003]
In order to effectively develop the secondary recrystallization accumulated in the {110} <001> orientation in the final annealing, it is extremely important to properly control the steel plate state before that, that is, after the decarburization annealing. The following three points are particularly important points to be controlled.
[0004]
The first is to disperse a dispersed phase called an inhibitor that suppresses grain growth to a uniform and appropriate size.
The inhibitor action suppresses the growth of primary recrystallized grains during the final finish annealing, but only the grains with the {110} <001> orientation, which has the most superior grain growth, engulf other orientations. Therefore, the inhibitor's restraining force must be controlled so that only the grains of {110} <001> orientation can grow and the growth of other grains can be prevented.
Typical examples of such inhibitors are sulfides such as MnS, MnSe, AlN and VN, Se compounds and nitrides, etc., which have extremely low solubility in steel. In this method, the inhibitor is controlled by controlling the inhibitory force by once completely dissolving the inhibitor during slab heating and then precipitating it finely in the subsequent steps.
[0005]
The second is to appropriately control the crystal grain size distribution after the primary recrystallization.
Studies have been conducted on the crystal grain size of the primary recrystallization structure from the viewpoint of controlling the driving force of secondary recrystallization. For example, JP-A-2-182866 discloses a primary recrystallized structure having an average primary recrystallized grain diameter of 15 μm or more and a coefficient of variation (standard deviation of grain size distribution normalized by the average diameter) of 0.6 or less. It is disclosed that it is important. Japanese Patent Laid-Open No. 4-337029 discloses that the amount of N in the steel in the annealing process before the final cold rolling is detected, and primary recrystallized grains in the range of 15 to 25 μm are obtained based on the result. A technique for changing a set temperature in recrystallization annealing is disclosed. Further, JP-A-6-33141 discloses that the primary recrystallized grains after decarburization annealing have an average diameter of 6 to 11 μm and a coefficient of variation of 0.5 or less, and the primary recrystallization immediately before the start of secondary recrystallization of final finish annealing. A technique for increasing the average diameter of recrystallized grains by 5 to 30% is disclosed.
[0006]
Thus, there are various theories on the optimal primary recrystallization grain size. In order to cause secondary recrystallization, it is important to finely control the balance between the driving force of grain growth and the inhibitory force of the inhibitor that suppresses it, and the inhibitor composition depends on the chemical composition and process conditions of the steel sheet. When the suppression force changes, the optimal driving force, that is, the optimal primary recrystallization grain size also changes.
[0007]
The third is proper control of the primary recrystallization texture.
Control of the inhibitor suppression force and grain growth driving force alone does not produce good secondary recrystallization, and the texture in the stage before final finish annealing is improved to the growth and orientation of the secondary grains ({110} <001>). The strength of the accumulation).
[0008]
  The present invention relates to such primary recrystallization texture control, and based on a new discovery that overturns conventional common knowledge, a primary recrystallization annealed plate having a texture advantageous for good secondary recrystallization is provided.Producing and using this as an intermediate material to produce unidirectional electrical steel with excellent magnetic propertiesTo do.
[0009]
Conventionally, with respect to the texture before final finish annealing, the main orientation is strongly accumulated in the {111} <112> orientation, and the {110} <001> orientation with high sharpness that becomes the nucleus of secondary recrystallization therein It has been considered important to exist. Such a concept is based on the theory that grain boundaries corresponding to Σ9 are easy to move, as disclosed in Japanese Patent Application Laid-Open No. 5-17I371 and Japanese Patent Publication No. 7-26155.
The Σ9 correspondence is that when the crystal lattices on both sides of the grain boundary are extended and overlapped and translated to match a pair of lattice points, 1 / Σ of the lattice points coincides with the adjacent lattice point In the case of the Σ9 correspondence, strictly speaking, the grains on both sides of the grain boundary are in a rotational relation of 38.9 ° around the <110> axis. In general, when the rotation angle is within a range of 38.9 ± 5.0 °, it can be regarded as a Σ9 correspondence (Brandon condition: 15 ° / Σ^1/2 If it is within the range, it can be regarded as a correspondence relationship).
[0010]
Since {110} <001> and {111} <112> have a rotational relationship of 35.3 ° around the <110> axis, they are within a range that can be regarded as a Σ9 relationship.
Therefore, in the primary recrystallized texture, a state in which {110} <001> having high sharpness is scattered in the base strongly accumulated in {111} <112> is the {110} <001> orientation. It has been considered advantageous for secondary recrystallization.
[0011]
Recently, it has been disclosed that the orientation of the base of the primary recrystallized annealing plate is not necessarily near {111} <112>, so that attention should also be paid to the secondary orientation. For example, JP-A-9-296219 and JP-A-9-256051 disclose that it is important to control the intensity of the {411} <148> direction which is the sub-direction. {110} <001> and {411} <148> are almost in a Σ9 correspondence, and here, the idea that a grain boundary in a Σ9 correspondence is easy to move was the basis.
[0012]
[Problems to be solved by the invention]
However, even in an ideal texture in view of such a correspondence, secondary recrystallization failure occurs, or there are many orientations deviated from {110} <001> although secondary recrystallization occurs. Since there are many cases where the magnetic properties of products often deteriorate, it is urgent to develop a primary recrystallized annealing plate as an intermediate material that can stably produce grain-oriented electrical steel sheets with good magnetic properties. It has become.
[0013]
  The present invention advantageously meets the above requirements,By controlling the assembly of the primary recrystallization annealed plate as an intermediate material,A grain-oriented electrical steel sheet with good magnetic properties can be manufactured stably.MethodThe purpose is to propose.
[0014]
[Means for Solving the Problems]
The inventors have previously found that the Goss orientation is independent of the secondary recrystallization and the Σ9 correspondence by analyzing the orientation distribution of the crystal grains in the middle of the secondary recrystallization. It was. And in JP-A-10-140297, in order to cause good secondary recrystallization, there are many orientation grains having an orientation difference of 20-40 ° from the Goss orientation after primary recrystallization. Disclosed that it is important.
This is presumably because when the crystal grains on both sides of the grain boundary have an orientation difference of 20 to 40 °, the grain boundary energy increases and the grain boundary moving speed increases.
Therefore, as a result of further diligent research, the inventors have found that grain boundaries with a misorientation of 30 ° have the highest grain boundary energy and are easy to move, even within a misalignment of 20 ° to 40 °. It was. Note that the orientation difference between the two directions here is the minimum rotation angle for overlapping the two directions.
[0015]
Therefore, it is important to have many azimuths with a difference of 30 ° from the Goth direction before the final annealing, but any direction with a difference of 30 ° from the Goss direction can be freely set. The orientation that is likely to appear in the primary recrystallized texture obtained as a result of rolling and annealing is limited to several.
Therefore, the primary recrystallization texture is analyzed in a three-dimensional orientation space, focusing on the first peak with the strongest accumulation and the second peak with the second strongest accumulation, and the center of these peaks is 30 ° from the Goss orientation. I hypothesized that it should be controlled so that
And as a result of many experiments and examinations based on this hypothesis, the present invention has been completed.
[0016]
  That is, the present inventionThe summary of is as follows.
1.C: 0.005-0.08 wt%,
    Si: 2.0 to 4.5 wt%,
    Mn: 0.03-2.5 wt%and
    Al: 0.003 to 0.050 wt%
TheContained, the balance is Fe and inevitable impurities composition silicon steel slab, hot-rolled, hot-rolled sheet annealed as necessary, then cold rolling more than once with intermediate or intermediate annealing In producing the unidirectional electrical steel by performing final annealing after the primary recrystallization annealing and then the final recrystallization annealing,
  In the steel plate stage after the primary recrystallization annealing, the texture near the surface layer of the steel plate is represented by Bunge Euler angle, φ₁= 5 °, Φ = 20 °, φ₂= To have a maximum orientation within 10 ° from 70 ° orientation,the aboveMaterial components,1200 ~ 1400 ℃Slab heatingtemperature,800 ~ 1150 ℃Hot-rolled sheet annealingtemperature,900 ~ 1100 ℃Intermediate annealingtemperature,80 ~ 300 ℃Cold rollingtemperatureand800 ~ 880 ℃Primary recrystallization annealingTemperatureA method for producing a unidirectional electrical steel sheet characterized by adjusting any one of conditions selected from.
  Here, the vicinity of the surface layer means that the subscale is removed from the surface and in the thickness direction. 50 μ m It means the part that is within.
[0017]
2. In 1 above,The texture near the surface layer of the steel sheet after primary recrystallization annealing is Bunge's Euler angle display.₁= 5 °, Φ = 20 °, φ₂= Maximum orientation within 10 ° from 70 ° orientation, and φ₁= 90 °, Φ = 60 °, φ₂A method for producing a unidirectional electrical steel sheet, characterized in that adjustment is made to have a maximum orientation within 5 ° from an orientation of 45 °.
3. The silicon steel slab further
    Se : 0.003 ~ 0.050 wt %and
    S: 0.003 ~ 0.050 wt %
3. One or two selected from among the above-mentioned items 1 or 2 above, The silicon steel slab further
    Sb : 0.001 ~ 0.3 wt %and
    Sn : 0.001 ~ 0.3 wt %
The manufacturing method of the unidirectional electrical steel sheet in any one of said 1-3 characterized by containing 1 type or 2 types selected from these.
5. The silicon steel slab further
    Cr : 0.001 ~ 0.3 wt %,
    Cu : 0.005 ~ 0.5 wt %,
    Nb : 0.OOl ~ 0.3 wt %and
    B: 0.0001 ~ 0.05wt %
The method for producing a unidirectional electrical steel sheet according to any one of the above 1 to 4, comprising one or more selected from among the above.
[0019]
For the display of crystal orientation by Euler angles, Roe's display method (ψ, θ, φ display) and Bunge display method (φ₁ , Φ, φ₂ Display).
[0020]
First, the display method of Roe is explained.
An orthogonal coordinate system fixed in space is X, Y, Z (X is an RD direction, Y is a TD direction, and Z is an ND direction), and an orthogonal coordinate system fixed to a crystal is x, y, z (x [100] direction, y is [010] direction, and z is [001] direction). From a state in which (X, Y, Z) and (x, y, z) coincide, the crystal is rotated φ around the Z axis (ND), then θ rotated around the Y axis (TD), and finally again The direction rotated by ψ around the Z axis (ND) is the (ψ, θ, φ) direction by the Roe display method.
[0021]
Bunge's notation has a slightly different definition of variables, but has the following relationship with Roe's notation:
φ₁(Bunge) ＝ ψ (Roe) + 90 °
Φ (Bunge) ＝ θ (Roe)
φ₂(Bunge) ＝ φ (Roe) −90 °
Recently, the Bunge display method is more commonly used. Therefore, in the present invention, the crystal orientation is expressed by the Bunge display method.
[0022]
The maximum direction is defined as follows.
In other words, Bunge's Euler angle display₁ , Φ, φ₂ Random intensity ratio of f (φ₁ , Φ, φ₂ ) And φ₁ = X, Φ = y, φ₂ The direction of = z is the maximum direction, which is defined as the following (1), (2) and (3) are all satisfied.
(1) For all positive and negative h values with sufficiently small absolute values,
f (x + h, y, z) −f (x, y, z) <0
(2) For all positive and negative k values with sufficiently small absolute values,
f (x, y + k, z) −f (x, y, z) <0
(3) For all positive and negative 1 values with sufficiently small absolute values,
f (x, y, z + 1) −f (x, y, z) <0
The random intensity ratio represents the existence ratio of a specific orientation,
(Existence ratio of parts with specific orientation at the measurement site) ÷
(Existence ratio of the part with the orientation in the hypothetical case where there is no orientation)
It is defined as
[0023]
For texture, a pole figure is measured from the diffraction intensity of X-rays, and a three-dimensional intensity distribution can be calculated from the result by an orientation distribution function (ODF). The intensity distribution can also be obtained by directly measuring the orientation of each crystal grain using EIectron Back Scattering Pattern (EBSP), Electron Channeling Pattern (ECP), or the like.
In general, the texture changes in the thickness direction of the plate.
In the present invention, the texture is measured in the vicinity of the surface layer of the sample (the portion where the subscale is removed from the sample surface and the thickness is within 50 μm). The reason for paying attention to the vicinity of the surface layer is that secondary recrystallized grains are relatively easy to generate and grow from the vicinity of the surface layer, and the texture at this position is extremely important for causing good secondary recrystallization.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the experimental results on which the present invention is based will be described.
C: 0.060 wt%, Si: 3.00 wt%, Mn: 0.08 wt%, Al: 0.020 wt%, N: 0.008 wt%, S: 0.001 wt%, Se: 0.020 wt%, Cu: 0.10 wt% and Sb: A plurality of slabs containing 0.020 wt% and the balance being Fe and inevitable impurities were prepared, heated to a temperature of 1200 to 1400 ° C., and hot-rolled to obtain a 2.3 mm thick hot rolled coil. Next, a part of the hot-rolled coil was sampled, subjected to hot-rolled sheet annealing in the laboratory, pickled, and then cold-rolled once with a tandem rolling mill to a thickness of 0.34 mm. At this time, the hot-rolled sheet annealing temperature was changed in the range of 800 to 1150 ° C, and the cold rolling temperature was changed in the range of 80 to 300 ° C. Thereafter, these rolled sheets were degreased and subjected to primary recrystallization annealing that also served as decarburization at 850 ° C. for 120 seconds, and then an annealing separator was applied, followed by final finish annealing.
[0025]
After the primary recrystallization annealing, a part of the sample was taken and the texture near the surface layer was measured. By changing the slab heating temperature, the hot-rolled sheet annealing temperature, and the cold rolling temperature, 22 samples with different primary recrystallization textures were prepared. The texture was measured by an X-ray pole figure, and a three-dimensional texture was calculated from the measured data. 3D texture is φ₁ , Φ, φ₂ Both were determined in 5 ° increments.
[0026]
After the final finish annealing, the unreacted separating agent was removed, and an insulating coating mainly composed of magnesium phosphate containing colloidal silica was applied and baked at 800 ° C. to obtain a product.
From each product, an Epstein-sized test piece is cut out along the rolling direction, and the magnetic flux density B₈ Was measured.
[0027]
From the analysis of the texture of the primary recrystallized annealed plate, the orientation that can appear frequently by rolling and recrystallization among orientations with an orientation difference of 30 ° from the Goss orientation is represented by the Bunge Euler angle, φ₁ = 90 °, Φ = 60 °, φ₂ = 45 ° (hereinafter abbreviated as (90 60 45)) and φ₁ = 5 °, Φ = 20 °, φ₂ = 70 ° (hereinafter abbreviated as (5 20 70)). However, it was found that (90 60 45) and (5 20 70) are not necessarily maximum orientations, and the maximum orientations shift considerably depending on process conditions.
Therefore, the maximum orientation and the magnetic properties B of the product₈ When the relationship with (T) was investigated, the results shown in Table 1 were obtained.
[0028]
[Table 1]

[0029]
As shown in the table, the maximum orientation in the vicinity of (5 20 70) shifts greatly depending on the process conditions. In Table 1, symbols a to v are attached in ascending order of the maximum azimuth closest to (5 20 70) and the azimuth difference between (5 20 70).
In order to improve the magnetic properties of the product, it is important to bring the maximum direction near (5 20 70) close to (5 20 70).₈ In order to obtain ≧ 1.85 (T), it is indispensable that the maximum direction exists within 10 ° from (5 20 70).
[0030]
As mentioned above, if the maximum orientation is within 10 ° from (5 20 70), the magnetic properties of the product will be good, but the maximum orientation in the vicinity of (90 60 45) is also brought closer to (90 60 45). As a result, the magnetic characteristics are further stabilized and improved.
The maximum azimuth in the vicinity of (90 60 45) is characterized by the fact that the peak position is less likely to change compared to (5 20 70), but delicate control of this azimuth peak is important. Control within the range of ° is effective to stabilize the magnetic properties.
[0031]
The results in Table 1 can be summarized as the relationship between the position of the maximum direction near (5 20 70) and the magnetic flux density of the product as shown in FIG.
[0032]
In the present invention, it is important whether or not the (5 20 70) orientation and the (90 60 45) orientation are maximum orientations, and the degree of integration is not particularly limited. Moreover, it is not limited whether another strong peak exists.
[0033]
Both {111} <112> and {411} <148>, which have been attracting attention in the past, are within the range of the corresponding azimuth relationship between Goss azimuth and Σ9 (Brandon condition), but are the subject of the present invention ( 5 20 70) and (90 60 45) are not within the range of the corresponding orientation relationship between Goss orientation and Σ9.
(5 20 70) has an orientation difference of 12.4 ° from {411} <148>, and is an orientation that has not been considered at all in the conventional texture control technology.
Further, (90 60 45) is close to {554} <225> in the Miller index display, and is known as a relatively frequently generated orientation as the primary recrystallization texture of the BCC metal polycrystalline material (steel sheet steel) Recrystallization and texture of steel; Showa 49 Iron and Steel Fundamental Research Group Recrystallization Section), as the primary recrystallization texture of unidirectional electrical steel sheet, from the viewpoint of the corresponding orientation relationship with Goss orientation {111} Attention has been attracted by <112>.
However, the present invention revealed that Goss orientation secondary recrystallization and the corresponding orientation relationship are irrelevant, and not (111) <112> but (90 60 45).
[0034]
Methods for controlling the texture of primary recrystallized annealed sheets include material components, slab heating conditions, hot rolling conditions, hot rolled sheet annealing conditions, intermediate annealing conditions, cold rolling conditions (especially rolling reduction, rolling temperature and aging). Adjustment of processing conditions) and primary recrystallization annealing conditions.
Specific examples for strongly accumulating the texture of primary recrystallized annealed plates, which had been strongly accumulated in {111} <112> and {411} <148> in the prior art, in (5 20 70) and (90 60 45) For example, there are the following methods.
[0035]
Method 1: A method of enlarging the grain size before the final cold rolling and promoting recrystallization from within the grains by significantly reducing the inhibitor component contained in the slab from the conventional level.
By promoting recrystallization from within the grains, recrystallization in the (5 20 70) direction becomes frequent, and peaks accumulated in {111} <112> ((90 54.7 45) in 3D display) Shifts in the direction of (90 60 45).
[0036]
Method 2: Method of promoting (5 20 70) orientation recrystallization from a band structure in which the <110> direction is aligned with the rolling direction by increasing the rolling temperature (warm rolling).
In particular, warm rolling with a tandem rolling mill is effective.
[0037]
Method 3: A method of adjusting the final cold rolling reduction ratio according to the material component (particularly the inhibitor component).
This is a method of using a combination of the property that the peak of accumulation of the primary recrystallized texture shifts when the material components are different and the property that the peak of accumulation of the primary recrystallized texture shifts when the rolling reduction is different.
[0038]
In the present invention, as described above, it is important to control the texture of the primary recrystallization annealing plate. Although the method of controlling is not particularly limited, it is generally desirable to comply with the following production conditions.
[0039]
  First, the component composition range of a raw material is demonstrated.
C: 0.005 wt% or more, 0.08 wt% or less
  C is an element necessary for improving the structure and stabilizing secondary recrystallization. For that purpose, C is contained in an amount of 0.005 wt% or more.There is a need. However, 0.If it exceeds 08 wt%, not only will the number of fractures during cold rolling increase, but the annealing time required for decarburization will become longer, leading to deterioration in productivity.There is a need.
[0040]
Si: 2.0 wt% or more, 4.5 wt% or less
  Si is an indispensable element for increasing electrical resistance and reducing iron loss. For this purpose, it is necessary to contain 2.0 wt% or more, but if it exceeds 4.5 wt%, the workability deteriorates, and Processing of the product becomes extremely difficult, so it should be contained in the range of 2.0 wt% or more and 4.5 wt% or less.There is a need.
[0041]
Mn: 0.03wt% or more, 2.5wt% or less
  Mn is also an element useful for increasing electrical resistance and improving hot workability during production. For this purpose, it is necessary to contain 0.03 wt% or more. However, if it exceeds 2.5 wt%, it induces γ transformation and deteriorates the magnetic properties, so 0.03 wtwt or more, 2.5 wt% The following rangeThere is a need.
[0042]
Inhibitor component
  Al, Se, S, Sb, Sn and the like are added as necessary to function as inhibitors. In these cases, the addition amounts of these elements are Al: 0.003 to 0.050 wt%, Se: 0.003 to 0.050 wt%, S: 0.003 to 0.050 wt%, Sb: 0.001 to 0.3 wt%, Sn: 0.001 to 0.3 wt, respectively.%WhenDoThere is a need.
[0043]
  Al combines with N to play an inhibitor role as AIN. In order to function effectively as an inhibitor, it is necessary to make a solid solution at the time of slab heating before hot rolling and to finely precipitate it at a subsequent slab, but if the content exceeds 0.050 wt%, The solution is incomplete, but if it is less than 0.003 wt%, the amount of inhibitor is insufficient and the effect cannot be exerted, so it should be contained in the range of 0.003 to 0.050 wt%.There is a need.
[0044]
  Se and S combine with Mn to play an inhibitor role as MnSe and MnS. In order to function effectively as an inhibitor, as with Al, it is necessary to make a solid solution during slab heating before hot rolling and to precipitate finely in the subsequent process, but when the content exceeds 0.050 wt%, On the other hand, if it is less than 0.003 wt%, the amount of the inhibitor is insufficient and the effect cannot be exerted, so it is contained in the range of 0.003 to 0.050 wt%.There is a need.
[0045]
  Sb and Sn segregate at the grain boundaries and function as inhibitors. In order to function sufficiently as an inhibitor, it is necessary to contain 0.001 wt% or more, but if it exceeds 0.3 wt%, the mechanical properties such as the bend characteristics of the product deteriorate, so it is contained in the range of 0.001 to 0.3 wt%. MakeThere is a need.
[0046]
  As an inhibitor, Cr, Cu, Nb, B, etc. can be added in addition to the above elements. The addition amount should be within a range that can sufficiently exert the inhibitor function and does not deteriorate the mechanical properties such as the bend characteristics of the product, Cr: 0.001 to 0.3 wt%, Cu: 0.005 to 0.5 wt%, Nb, respectively. : 0.001 to 0.3 wt%, B: 0.0001 to 0.05 wt%%WhenDoThere is a need.
  Recently, there has been reported a technique for generating secondary recrystallization by utilizing the orientation difference dependency of grain boundary mobility without adding an inhibitor element. This technique is also disclosed in the present invention. It is an adaptable technology.
[0047]
Next, the manufacturing process will be described.
Hot rolling process
The slab adjusted to the above component composition is subjected to slab heating in accordance with a normal method, and is then formed into a hot-rolled coil by hot rolling.
In recent years, a method of directly hot rolling after continuous casting without performing slab heating has been proposed, but this method can also be applied to the present invention.
[0048]
Hot-rolled sheet annealing process
If necessary, the hot-rolled coil is subjected to hot-rolled sheet annealing in the temperature range of 800 to 1150 ° C. in order to homogenize the structure and finely precipitate the inhibitor.
[0049]
Cold rolling and intermediate annealing process
The steel sheet after the hot rolling coil or the hot rolled sheet annealing is subjected to cold rolling at least once and sandwiching the intermediate annealing to obtain a product sheet thickness. Cold rolling may be performed by a tandem rolling mill or a Sendzimir rolling mill. The rolling temperature may be normal temperature, or higher than normal temperature if necessary, and the texture can be controlled using dynamic strain aging during rolling and static strain aging between passes. It is.
[0050]
Decarburization and primary recrystallization annealing process
The steel sheet rolled to the product thickness is subjected to annealing for decarburization and primary recrystallization.
[0051]
The primary recrystallization annealed plate thus obtained is used as an intermediate material for producing a unidirectional electrical steel sheet.
In general, an annealing separator is applied, finish annealing is performed, an insulating coating is applied and baked as necessary, and a flattening annealing is performed to obtain a product.
[0052]
【Example】
Example 1
C: 0.045 wt%, Si: 3.25 wt%, Mn: 0.08 wt%, Al: 0.005 wt%, N: 0.004 wt%, S: 0.002 wt%, Se: 0.001 wt%, Cu: 0.01 wt% and Sb: A plurality of slabs containing 0.010 wt% and the balance being Fe and inevitable impurities were prepared, heated to 1200 ° C., and hot-rolled to obtain a 2.5 mm thick hot rolled coil. Next, the hot-rolled coil was subjected to hot-rolled sheet annealing, pickled, and then cold-rolled once with a tandem rolling mill to a thickness of 0.34 mm. At this time, the hot-rolled sheet annealing temperature was changed in the range of 800 to 1150 ° C, and the cold rolling temperature was changed in the range of 80 to 300 ° C. Thereafter, degreasing treatment was performed, and primary recrystallization annealing was performed at 800 to 880 ° C. for 120 seconds.
Thus, primary recrystallized annealing plates having greatly changed textures as shown in Table 2 with numbers 1 to 20 were obtained.
A part of these primary recrystallization annealed plates was collected and the texture near the surface layer was measured. The texture was measured by an X-ray pole figure, and a three-dimensional texture was calculated from the measured data. 3D texture is φ₁ , Φ, φ₂ Both were determined in 5 ° increments.
[0053]
Subsequently, an annealing separator was applied to these primary recrystallization annealed plates, and then final finish annealing was performed. After the final finish annealing, after removing the unreacted separating agent, an insulating coating mainly composed of magnesium phosphate containing colloidal silica was applied and baked at 800 ° C. to obtain a product.
From each product, an Epstein-sized test piece is cut out along the rolling direction, and the magnetic flux density B₈ Was measured.
Table 2 shows the maximum orientation in the texture of the primary recrystallization annealed plate and the magnetic flux density B of the product.₈ Indicates.
[0054]
[Table 2]

[0055]
As shown in the table, when a product was manufactured using the primary recrystallization annealed plate according to the present invention, a product with extremely good magnetic flux density could be obtained.
[0056]
Example 2
C: 0.070 wt%, Si: 3.25 wt%, Mn: 0.08 wt%, Al: 0.025 wt%, N: 0.009 wt%, S: 0.002 wt%, Se: 0.020 wt%, Cu: 0.10 wt%, Sb: A plurality of slabs containing 0.020 wt% and Sn: 0.12 wt% with the balance being Fe and inevitable impurities were prepared, heated to 1400 ° C., and hot rolled to obtain a 2.5 mm thick hot rolled coil. Subsequently, hot-rolled sheet annealing was performed by holding at a temperature of 800 to 1150 ° C. for 60 seconds. After pickling, the first cold pressing was performed at room temperature with a tandem rolling mill to a thickness of 1.7 mm, followed by intermediate annealing at a temperature of 950 ° C., pickling again, and a thickness of 0.22 mm The second cold rolling was performed with a Sendzimir rolling mill. In the second cold rolling, the rolling temperature was changed in the range of 80 to 300 ° C. Next, after the degreasing treatment, primary recrystallization annealing was performed at 800 to 880 ° C. for 120 seconds.
Thus, primary recrystallized annealed plates having greatly changed texture as shown by the symbols A to N in Table 3 were obtained.
A part of these primary recrystallization annealed plates was collected and the texture near the surface layer was measured. The texture was measured by an X-ray pole figure, and a three-dimensional texture was calculated from the measured data. 3D texture is φ₁ , Φ, φ₂ Both were determined in 5 ° increments.
[0057]
Subsequently, an annealing separator was applied to these primary recrystallization annealed plates, and then final finish annealing was performed. After the final finish annealing, the unreacted separating agent was removed, and then an insulating coating mainly composed of magnesium phosphate containing colloidal silica was applied and baked at 800 ° C.
From each product, an Epstein-sized test piece is cut out along the rolling direction, and the magnetic flux density B₈ Was measured.
Table 3 shows the maximum orientation in the texture of the primary recrystallization annealed plate and the magnetic flux density B of the product.₈ Indicates.
[0058]
[Table 3]

[0059]
As shown in the table, all the unidirectional electrical steel sheets obtained using the primary recrystallization annealed plate according to the present invention have a good magnetic flux density.
[0060]
Example 3
C: 0.040 wt%, Si: 2.90 wt%, Mn: 0.08 wt%, Al: 0.003 wt%, N: 0.003 wt%, S: 0.001 wt%, Se: 0.020 wt%, Cu: 0.01 wt%, Sb: A plurality of slabs containing 0.020 wt% and the balance consisting of Fe and inevitable impurities were prepared, heated to 1200 ° C., and hot-rolled to obtain a 2.8 mm thick hot rolled coil. Then, it pickled and the 1st cold rolling was performed at normal temperature with the tandem rolling mill. The plate thickness (intermediate thickness) after the first cold rolling was changed in the range of 0.50 to 2.0 mm. Then, after intermediate annealing at a temperature of 900 ° C. to 1100 ° C., pickling was performed again, and a second cold rolling to a thickness of 0.22 mm was performed by a Sendzimir rolling mill. In the second cold rolling, the rolling temperature was changed in the range of 80 to 300 ° C. After that, degreasing treatment was performed, and primary recrystallization annealing was performed at 850 ° C. for 120 seconds.
Thus, a primary recrystallized annealed plate having a greatly changed texture as shown in Table 4 by the symbol “Ana” was obtained.
A part of these primary recrystallization annealed plates was collected and the texture near the surface layer was measured. The texture was measured by an X-ray pole figure, and a three-dimensional texture was calculated from the measured data. 3D texture is φ₁ , Φ, φ₂ Both were determined in 5 ° increments.
[0061]
Subsequently, an annealing separator was applied to these primary recrystallization annealed plates, and then final finish annealing was performed. After the final finish annealing, the end reaction separating agent was removed, and then an insulating coating mainly composed of magnesium phosphate containing colloidal silica was applied to obtain a baked product at 800 ° C.
From each product, an Epstein-sized test piece is cut out along the rolling direction, and the magnetic flux density B₈ Was measured.
Table 4 shows the maximum orientation in the texture of the primary recrystallization annealed sheet and the magnetic flux density B of the product.₈ Indicates.
[0062]
[Table 4]

[0063]
As shown in the table, the magnetic flux density of the product was improved by using the primary recrystallization annealing plate of the present invention.
[0064]
【The invention's effect】
Thus, according to the present invention, by properly controlling the texture of the primary recrystallization annealed plate, it became possible to stably produce a grain oriented electrical steel sheet having good magnetic properties.
[Brief description of the drawings]
FIG. 1 is a diagram showing the relationship between the position of the maximum orientation near (5 20 70) in a primary recrystallization texture and the magnetic flux density of a product.

Claims (5)

C: 0.005-0.08 wt%,
Si: 2.0 to 4.5 wt%,
Mn: 0.03-2.5 wt% and
Al: 0.003 to 0.050 wt %
The remainder of the steel steel slab with a composition of Fe and unavoidable impurities is hot-rolled and subjected to hot-rolled sheet annealing as necessary, and then one or two or more cold sandwiches between intermediate annealing When producing a unidirectional electrical steel by rolling to a final plate thickness, then performing primary annealing after primary recrystallization annealing,
In the steel plate stage after the primary recrystallization annealing, the texture near the surface layer of the steel plate is within 10 ° from the orientation of φ ₁ = 5 °, φ = 20 °, φ ₂ = 70 ° in the Bunge Euler angle display. to have a maximum orientation, the material component, 1200 ~ 1400 ° C. the slab heating temperature, 800 ~ 1150 ° C. hot-rolled sheet annealing temperature, 900 ~ 1100 ° C. of the intermediate annealing temperature, 80-300 inter ° C. cold rolling temperature and A method for producing a unidirectional electrical steel sheet, characterized by adjusting any one of conditions selected from a primary recrystallization annealing temperature of 800 to 880 ° C.
Here, the vicinity of the surface layer, to remove the sub-scale from a surface, it means within containing portion 50 mu m in the thickness direction. In claim 1, the texture in the vicinity of the surface layer of the steel sheet after the primary recrystallization annealing is 5 ° from the orientation of φ ₁ = 90 °, φ = 60 °, φ ₂ = 45 ° in Bunge's Euler angle display. A method for producing a unidirectional electrical steel sheet, characterized in that the maximum orientation is adjusted within the range. The silicon steel slab further
Se : 0.003 ~ 0.050 wt %and
S: 0.003 ~ 0.050 wt %
The method for producing a unidirectional electrical steel sheet according to claim 1, comprising one or two selected from among the above. The silicon steel slab further
Sb : 0.001 ~ 0.3 wt %and
Sn : 0.001 ~ 0.3 wt %
The manufacturing method of the unidirectional electrical steel sheet in any one of Claims 1-3 characterized by including the 1 type or 2 types selected from these. The silicon steel slab further
Cr : 0.001 ~ 0.3 wt %,
Cu : 0.005 ~ 0.5 wt %,
Nb : 0.OOl ~ 0.3 wt %and
B: 0.0001 ~ 0.05wt %
A method for producing a unidirectional electrical steel sheet according to any one of claims 1 to 4, comprising one or more selected from among the above.

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