JP4123847B2 - Oriented silicon steel sheet - Google Patents

Description

【００２０】
【表２】

【００２１】
同表から明らかなように、焼鈍分離剤中に、タリウムや鉛の塩化物またはふっ化物を少量添加すると共に、 800〜900 ℃の温度域を徐加熱とすることにより、｛１１０｝面の板面に対する角度を４〜８°の適正範囲に制御することができるだけでなく、安定した鏡面化が達成されると共に、鋼板の純化が促進され、その結果ヒステリシス損（Ｗh_17/50）を効果的に低減することができた。
特に、1000℃以上における水素分圧を 0.9 atm以上にした場合には、鋼板の純化および鏡面化が一層促進され、さらに、 600〜900 ℃における範囲をAr雰囲気とした場合には、フォルステライト被膜の形成が格段に抑制されると共に、一層の純化、ひいては低Ｗh_17/50化が達成されている。
【００２２】
なお、塩化タリウムや塩化鉛等の添加量が 0.1重量部よりも少ないとフォルステライト被膜の形成が顕著になり、安定してRa≦0.4 μm という鏡面が得られず、一方添加量が10重量部を超えたり、 800〜900 ℃の温度域の昇温速度が８℃/hを上回った場合には、｛１１０｝面の板面に対する角度を安定して４〜８°の範囲におさめることができず、その結果、この発明で所期したほど良好な低履歴損失を得ることができなかった。
【００２３】
また、発明者らの研究によれば、｛１１０｝面の板面に対する角度は、インヒビター形成元素であるＳ，Se量と強い相関があり、Ｓ量を 0.005mass％未満に抑制すると共に、Se量を0.01〜0.03mass％の範囲に制限することが好ましい。
【００２４】
実験２
Ｓ量およびSe量をそれぞれ、Ｓ：0.002 mass％、Se：0.02mass％にすること以外、上記の実験１と同様にして実質的にフォルステライト被膜を有しない方向性珪素鋼板を製造した。
なお、この時、焼鈍分離剤中に添加した添加物および二次再結晶焼鈍条件は、表３に示したとおりである。
かくして得られた製品板について、実験１と同様な調査を行った結果を表４に示す。
【００２５】
【表３】

【００２６】
【表４】

【００２７】
表４に示したとおり、インヒビター形成元素として添加するＳ量を抑制すると共に、Seを適正量添加することにより、二次再結晶後の｛１１０｝面の板面に対する角度を４〜６°の最適範囲に的確に制御することができ、その結果、ヒステリシス損を安定して低減することができた。
なお、この場合でも、1000℃以上における水素分圧を 0.9 atm以上にし、さらには 600〜900 ℃における範囲をAr雰囲気とすることが、鋼板の純化および鏡面化ひいては低Ｗ h _17/50 化の面でに有利であることに変わりはなかった。
【００２８】
この発明に従い、焼鈍分離剤中にタリウムや鉛の塩化物またはふっ化物を少量添加すると共に、二次再結晶昇温過程中、 800〜900 ℃の温度範囲を徐熱することによって、｛１１０｝面の方位が的確に制御されるだけでなく、鋼板表面が平滑化されて炭化物等の有害成分が減少する機構については、まだ明確に解明されたわけではないが、タリウムまたは鉛と塩素またはふっ素元素との相乗作用によって、｛１１０｝面の鋼板表面エネルギーが変化するか、あるいは二次再結晶時の粒界移動速度に影響を与えて、特定方位の二次再結晶粒の成長を促す等の作用で二次再結晶粒の主方位が定まり、しかもこのような粒界移動時に純化も促進されるためと考えられる。
【００２９】
次に、この発明の方向性珪素鋼板において、その構成要件を前記の範囲に限定した理由について説明する。
この発明の方向性珪素鋼板は、フォルステライト被膜を形成させることなく製造して得た方向性珪素鋼板に限定される。
成分組成については次のとおりである。
Si：1.5 〜7.0 mass％
Siは、鋼板の電気抵抗を高め、鉄損を低減するのに有効な成分であるが、含有量が 7.0mass％を超えると硬くなって加工が困難となり、一方 1.5mass％に満たないと二次再結晶焼鈍中に変態を生じて安定した二次再結晶組織が得られないので、Si含有量は 1.5〜7.0 mass％の範囲に限定した。
なお、製品板中におけるＣ，Ｓ，SeおよびＮなどの元素はいずれも、磁気特性上有害な作用があり、特に鉄損を劣化させるので、製品板においてはそれぞれ、Ｃ：0.003 mass％以下、Ｓ，Se：0.002 mass％以下、Ｎ：0.002 mass％以下程度に低減することが望ましいが、後述するように、この発明では、析出物量の総和を所定量以下まで低減することが特に重要である。
【００３０】
｛１１０｝面の板面に対する角度：４〜８°
この規定は、この発明において特に重要であり、二次再結晶後の結晶粒については、その｛１１０｝面を板面に対して面積加重平均で４〜８°だけ傾けさせることが肝要である。
これは、従来知られている圧延方向と＜１００＞軸との傾きの変化による磁区細分化効果だけではなく、圧延方向と直角方向の＜１１０＞軸と板面とのなす角度が履歴損に大きな影響を与えるからであり、この効果は、フォルステライト被膜あるいはそのアンカーによる凹凸を持たない鏡面化鋼板で特に大きい。
ここに、この角度が４°に満たなかったり、８°を超えた場合には、この発明で所期したほどの低鉄損を得ることができない。
【００３１】
表面粗さRa：0.4 μm 以下
表面粗さRaが 0.4μm を超えると、ヒステリシス損の劣化等の不利が生じるだけでなく、後述する炭化物等の有害成分が増大して、鉄損の低減が達成できない。
そこで、この発明では、鋼板の表面粗さRaにつき 0.4μm 以下に限定した。
【００３２】
炭化物、硫化物およびセレン化物の総量が（Ｃ＋Ｓ＋Se）重量で35 ppm以下
炭化物、硫化物およびセレン化物等の析出物はいずれも、磁壁の移動を阻害してヒステリシス損ひいては鉄損を劣化させる有害成分であるので、極力低減することが好ましいが、35 ppm以下であれば許容できる。
【００３３】
Ｗ h _17/50 ：0.35 W/kg 以下
この発明では、上述したとおり、｛１１０｝面の板面に対する角度を２〜８°の範囲に制御すると共に、表面粗さRaを 0.4μm 以下、（Ｃ＋Ｓ＋Se）量を35 ppm以下とすることにより、低Ｗ h _17/50 化を安定して達成することができるので、従来実現が難しかったＷ h _17/50 ≦0.35 W/kg を特徴事項として掲げた。
【００３４】
また、この発明では、張力コーティングを付与することにより、わずかな張力で効果的にＷ h _17/50 を 0.30 W/kg以下まで低減することができる。
さらに、この発明では、製造工程の途中または製造後に、線状または点状の歪付加領域または溝形成等による磁区細分化処理が施すことによって、鉄損を一層低減することもできる。
なお、鋼板の板厚は特に限定されることはないが、渦電流損のうち古典的渦電流損は板厚の関数であるので、要求される鉄損に応じてコストとの勘案の上で定められ、通常0.10〜0.25mm程度とすることが好ましい。
【００３５】
次に、この発明の方向性電磁鋼板の製造方法について説明する。
まず、素材の成分組成範囲について説明する。
Si：1.5 〜7.0 mass％
製品である方向性電磁鋼板について説明したとおり、含有量が 1.5mass％に満たないと二次再結晶焼鈍中に変態を生じて安定した二次再結晶組織が得られず、一方 7.0mass％を超えると固くなって加工が困難となるので、Si含有量は 1.5〜7.0 mass％の範囲に限定した。
【００３６】
Al：0.06mass％以下、Ｎ：0.01mass％以下
Alは、Ｎと結合し、インヒビターとして有用なAlＮを形成する。特に初期鋼中にAlを 0.006mass％以上含有させることによって結晶配向性を一層向上させることができる。しかしながら、0.06mass％を超えて含有させると再び結晶配向性の劣化が生じるので、Alは0.06mass％以下に限定した。
また、Ｎ含有量が 0.01 mass％を超えるとふくれ欠陥の発生が懸念されるので、Ｎ量は0.01mass％以下に限定した。なお、下限は特に規定しないけれども、20 ppm以下まで低下させるのは経済的な不利が大きい。
【００３７】
Seおよび／またはＳ：0.01〜0.06mass％、Mn：0.02〜0.2 mass％
Se，ＳとMnは、互いに結合して、インヒビターMnSe，MnＳを形成する。ここに適正量のMnSe，MnＳを確保するためには、初期鋼中に（Se＋Ｓ）の和で0.01mass％以上、0.06mass％以下と、Mn：0.02〜0.2 mass％を不可欠とする。というのは、これらの量がそれぞれ下限に満たないと二次再結晶を好適に生じさせるためのインヒビター量が不足し、一方上限を超えると熱間圧延前の固溶が困難となるからである。
なお、後述するように、最終冷延後、２次再結晶焼鈍前の間に増窒素処理を行う場合には、Se，ＳおよびMnの添加は必ずしも必要とはしないが、Mnについては鋼の延性改善等を目的として添加することが好ましい。
【００３８】
また、前記実験２において述べたとおり、Ｓ，Se量は、｛１１０｝面の板面に対する角度と強い相関があり、この角度を４〜６°の好適範囲に制御するためには、Ｓ量を 0.005mass％未満に抑制すると共に、Se量を0.01〜0.03mass％の範囲に制限することが好適である。
【００３９】
Ｂ，Bi，Sb，Mo，Te，Sn，Ｐ，Ge，As，Nb，Ni，Cr，Ti，Cu，Pb，ZnおよびInのうちから選んだ少なくとも１種：0.0005〜2.0 mass％
これらの元素はいずれも、表面や粒界への偏析、析出物形成等によって、二次再結晶方位を制御する目的で添加されるものであるが、含有量が0.0005mass％に満たないとその添加効果に乏しく、一方 2.0mass％を超えると磁東密度の低下を招くので、単独使用または併用いずれの場合においても0.0005〜2.0 mass％の範囲で含有させるものとした。
【００４０】
さらに、この発明では、初期鋼中に、熱間圧延中での再結晶を促進して磁気特性を向上させる目的で、Ｃを0.0050〜0.08mass％程度の範囲で含有させることもできる。
【００４１】
次に、具体的な製造工程について説明する。
所定の成分に調整された鋼塊やスラブを、公知の方法により、熱間圧延および冷間・温間圧延して最終板厚とする。鋼素材としては、連続熱延法やシートバーキャスト法、ストリップキャスト法等で得たものを適用することもできる。
【００４２】
ついで、１次再結晶焼鈍後、２次再結晶焼鈍を施すが、この発明では、最終冷延後、２次再結晶焼鈍前の間に増窒素処理を施すこともできる。
この処理は、鋼板表面の窒素濃度を上昇させて、２次再結晶時にAlＮによるインヒビター機能を強化させるために行うものである。
従って、この処理を行う場合には、スラブ段階においてAlＮを固溶させるための高温加熱処理が必ずしも必要ではないので、スラブ加熱温度を1280℃以下程度まで低減できる利点がある。
【００４３】
さて、２次再結晶焼鈍を施す場合には、それに先立ち、鋼板の表面に焼鈍分離剤を塗布するが、この発明では、この焼鈍分離剤中にタリウムまたは鉛の塩素化合物またはふっ素化合物を含有させることが好適である。
というのは、これらタリウムまたは鉛の塩素化合物またはふっ素化合物は、前記実験１で述べたとおり、少量の添加で｛１１０｝面の板面に対する角度を適正範囲に制御できるだけでなく、安定した鏡面化および純化が達成され、その結果ヒステリシス損（Ｗ h _17/50 ）を効果的に低減することができるからである。
【００４４】
ここに、タリウムまたは鉛の塩素化合物またはふっ素化合物の添加量は、通常の焼鈍分離剤：100 重量部に対し 0.1〜10重量部の範囲とすることが好ましい。というのは、0.1 重量部に満たないとその添加効果に乏しく、一方10重量部を超えると従来より少量とはいえ塩化物に起因した炉体の腐食や製品板における発錆が懸念されるからである。
なお、焼鈍分離剤の主成分としては、MgＯやA1₂O₃ など従来公知のものいずれもが使用できる。
また、塗布方法としては、静電塗布や水スラリー塗布など公知の手法を用いることができる。塗布量については３〜30 g/m² 程度が好適である。
さらに、金属塩化物、水酸化物、ほう酸塩、硝酸塩、燐酸塩、炭酸塩、硫酸塩および硫化物を適宜加えて上記の分離剤を補足することも可能である。
【００４５】
ついで、上記のようなタリウムまたは鉛の塩素化合物またはふっ素化合物を適量添加した焼鈍分離剤を鋼板表面に塗布したのち、２次再結晶焼鈍を施すわけであるが、この２次再結晶焼鈍工程中、特にその昇温過程において 800℃から 900℃までの昇温速度を８℃/h以下の徐加熱とすることが好ましい。
というのは、 800〜900 ℃における昇温速度が８℃/hを上回ると、二次再結晶の方位安定性が低下するからである。
【００４６】
かくして、実質的にフォルステライト被膜の形成がない鏡面化状態で、炭化物等の析出も少なく、また｛１１０｝面の方位が的確に制御された方向性珪素鋼板が得られるのである。
【００４７】
ところで、この発明において、鋼板表面の鏡面化および純化を一層促進するためには、1000℃以上における水素分圧を 0.9 atm以上にすることが望ましい。
というのは、1000℃以上における水素分圧を 0.9 atm以上にすれば、表面酸化物の形成が抑制されると共に、H₂ＳやH₂Seが効果的に気化されることにより、鋼板表面の鏡面化および純化が一層促進されるからである。
【００４８】
また、 600〜900 ℃における範囲をAr雰囲気としてやれば、フォルステライト被膜の形成が格段に抑制され、一層の鏡面化および純化が達成される。
この点、広く行われている窒素雰囲気では、フォルステライト等の被膜の前駆体酸化物の形成が促進される。
従って、この場合には、焼鈍分離剤に添加する塩化物量が少量でも所望の目的を達成することができる利点がある。
ここに、上記したAr雰囲気は、必ずしも 600℃から 900℃までの全温度範囲にわたって実施する必要はなく、この温度範囲の一部の温度域でも良い。
【００４９】
なお、この発明では、上記したような２次再結晶焼鈍による鏡面化後、さらにNaC1電解等で一層の表面平滑化を行うなど、公知の手法との組み合わせも可能である。
また、この発明では、上記のようにして得た鏡面化方向性珪素鋼板の表面に、張力被膜を被成した一層の鉄損低減を図ることもできる。
ここに、張力被膜としては、りん酸塩系の被膜およびＰＶＤ等によるセラミック被膜など、従来公知のものいずれもが適合する。
さらに、この発明は、従来の磁区細分化技術との併用が可能で、併用により加算的以上の相乗効果が得られる。ここでいう磁区細分化技術とは、例えば製品の鋼板表面にレーザーやプラズマジェットを照射して局所的に歪領域を設ける方法、鋼板表面に溝を設ける方法、鋼板表面の組織もしくは組成を被膜も含めて局所的に変更する方法などが挙げられ、実際の処理に際しても突起ロールやエッチング法など従来公知のものが適用できる。
【００５０】
【実施例】
実施例１
Ｃ：0.05mass％、Si：3.2 mass％、Mn：0.06mass％、Ｓ：0.03mass％、A1：0.02mass％、Ｎ：80 ppm，Sn：0.3 mass％およびCu：0.2 mass％を含有し、残部はFeおよび不可避的不純物からなるスラブを、1370℃に加熱したのち、熱間圧延により 2.0mm厚の熱延板とし、ついで温間圧延により板厚：0.21mmの最終板厚に仕上げたのち、脱炭を兼ねた１次再結晶焼鈍を施した。
この鋼板を２分割し、一方には A1₂0₃：100 重量部に対してふっ化鉛を0.15重量部添加した焼鈍分離剤を（発明例）、他方には A1₂0₃単独の焼鈍分離剤（比較例）をそれぞれ静電塗布により 18 g/m²塗布し、 800℃までN₂雰囲気中で平均50℃/hの速度で昇温し、 800℃から 900℃まで（25%N₂+75%H₂)の混合雰囲気中にて平均 4.5℃/hの速度で昇温し、その後、水素＋窒素混合雰囲気中（水素分圧：0.8 atm)で1200℃まで平均14℃/hの速度で昇温し、引き続き1200℃で６時間の純化を兼ねた二次再結晶仕上げ焼鈍を施したのち、放冷して、フォルステライト被膜のない方向性珪素鋼板を得た。
【００５１】
かくして得られた方向性珪素鋼板の｛１１０｝面の板面となす角度の平均値（面積加重平均）は、発明例は 4.6°であったのに対し、比較例は 9.9°であった。
また、鋼板表面の粗度は、発明例はRa：0.32μm 、比較例はRa：0.45μm であった。
さらに、発明例では、残留炭化物量は８ ppm、硫化物は主にCu₂Sが22 ppm，Se化物は主にMnSeが３ ppmで、（Ｃ＋Ｓ＋Se）合計で33 ppmであり、またＷ h _17/50 ＝0.33 W/kg であったのに対し、比較例はそれぞれ15 ppm，35 ppm，５ ppmで、（Ｃ＋Ｓ＋Se）合計で55 ppmであり、Ｗ h _17/50 ＝0.51 W/kg であった。
【００５２】
また、上記の発明例についての製造工程中、1000℃以上の温度域における水素分圧を 1.0 atmまで上げた場合には、｛１１０｝面の板面と成す角度の平均値は3.8 °、鋼板の表面粗度はRa：0.29μm 、（Ｃ＋Ｓ＋Se）合計：26 ppmで、Ｗ h _17/50 ＝0.30 W/kg という良好なヒステリシス損が得られた。
【００５３】
さらに、上記の製造工程中、 800℃までの昇温雰囲気をAr雰囲気としたところ、｛１１０｝面の板面と成す角度の平均値は4.5 °、鋼板の表面粗度はRa：0.26μm 、（Ｃ＋Ｓ＋Se）合計：23 ppmで、Ｗ h _17/50 ＝0.28 W/kg という一層良好なヒステリシス損が得られた。
【００５４】
実施例２
Si：3.2 mass％、Mn：0.06mass％、Al：0.02mass％、Ｎ：80 ppm，Sb：0.1 mass％およびBi：0.0005mass％を含有し、残部はFeおよび不可避的不純物からなるスラブを、1150℃に加熱したのち、熱間圧延により 2.0mmの熱延板とし、ついで熱延板焼鈍後、冷間圧延により板厚：0.29mmに仕上げたのち、１次再結晶焼鈍を施した。
ついで、H₂＋N₂＋アンモニア混合雰囲気中で、 800℃，１ minの増窒素処理を施したのち、MgＯ：100 重量部に対して塩化タリウム：６重量部を添加した焼鈍分離剤を水スラリーで 14 g/m²塗布し、乾燥後、 800℃までをN₂雰囲気中で平均50℃/hの速度で昇温し、 800℃から 900℃までを（25%N₂+75%H₂)の混合雰囲気中にて平均 4.5℃/hの速度で昇温し、 900℃から1150℃までを水素＋窒素混合雰囲気中（水素分圧：0.8 atm)で平均20℃/hの速度で昇温し、その後水素中で1150℃, ６時間の純化焼鈍を兼ねた二次再結晶仕上げ焼鈍を施したのち、放冷して、フォルステライト被膜のない方向性珪素鋼板を得た。
【００５５】
かくして得られた方向性珪素鋼板の｛１１０｝面の板面と成す角度の平均値は3.2 °であり、鋼板の表面粗度はRa：0.25μm 、残留炭化物量は16 ppm、硫化物は主にMnＳで８ ppm，Se化物は主に Cu₂Seで４ ppmで、（Ｃ＋Ｓ＋Se）合計で28 ppmであり、またＷ h _17/50 ＝0.33 W/kg であった。
【００５６】
また、上記の処理中、1000℃以上の温度域における水素分圧を 1.02 atm まで上げた場合には、｛１１０｝面の板面と成す角度の平均値は 4.1°、鋼板の表面粗度はRa：0.22μm 、（Ｃ＋Ｓ＋Se）合計：22 ppmで、Ｗ h _17/50 ＝0.25 W/kg という良好なヒステリシス損値が得られた。
【００５７】
さらに、上記の処理中、 800℃までの昇温雰囲気をAr雰囲気としたところ、｛１１０｝面の板面と成す角度の平均値は 4.4°、鋼板の表面粗度はRa：0.20μm、（Ｃ＋Ｓ＋Se）合計：18 ppmで、Ｗ h _17/50 ＝0.23 W/kg という一層良好なヒステリシス損が得られた。
【００５８】
実施例３
Ｃ：0.06mass％、Si：3.2 mass％、Mn：0.06mass％、Ｓ：0.002 mass％、Se：0.02mass％、Al：0.03mass％、Ｎ：90 ppm，Sb：0.07mass％、Cu：0.2 mass％およびNi：0.1 mass％を含有し、残部はFeおよび不可避的不純物からなるスラブを、1410℃に誘導加熱したのち、熱間圧延により 2.0mmの熱延板とし、ついで熱延板焼鈍後、冷間圧延と中間焼鈍に引き続く温間圧延により板厚：0.19mmに仕上げたのち、NaCl電解槽中で線状の磁区細分化溝（溝幅：0.2 mm、溝深さ：15μm 、溝間隔：３mm）を形成した。
その後、脱炭を兼ねた１次再結晶焼鈍を施したのち、MgＯ：100 重量部に対して塩化鉛を0.15重量部添加した焼鈍分離剤を、水スラリーで塗布し、焼き付け乾燥後、 800℃までをAr雰囲気中で平均30℃/hの速度で昇温し、 800℃から900 ℃までをAr雰囲気中で平均 6.5℃/hの速度で昇温し、その後、1.02 atmの水素雰囲気中で1200℃まで10℃/hの速度で昇温し、この温度で４時間の純化を兼ねた二次再結晶焼鈍を施したのち、放冷して、フォルステライト被膜のない方向性珪素鋼板を得た。
【００５９】
かくして得られた方向性珪素鋼板の｛１１０｝面の板面と成す角度の平均値は5.2 °であり、鋼板表面の粗度はRa：0.19μm 、残留炭化物は５ ppm、硫化物は分析下限（１ ppm）未満、Se化物は主にMnSeで２ ppmで、（Ｃ＋Ｓ＋Se）合計で約７ ppmであり、またＷ h _17/50 ＝0.21 W/kg 、Ｗ_17/50 ＝0.58 W/kg であった。
【００６０】
さらに、この鋼板に、軽酸洗と片側 0.5μm のNaCl水溶液中での電解研磨を施したところ、Ｗ h _17/50 は 0.18 W/kgまで低減し、さらにCrめっきによる張力コーティングを施したところ、Ｗ h _17/50 ＝0.17 W/kg 、Ｗ_17/50 ＝0.49 W/kg という良好な鉄損値が得られた。
【００６１】
実施例４
Ｃ：0.06mass％、Si：3.2 mass％、Mn：0.06mass％、Ｓ：0.001 mass％、Se：0.03mass％、Sb：0.07mass％およびMo：0.02mass％を含有し、残部はFeおよび不可避的不純物からなるスラブを、1410℃に誘導加熱したのち、熱間圧延により2.0mm の熱延板とし、ついで熱延板焼鈍後、冷間圧延と中間焼鈍に引き続く温間圧延により板厚：0.19mmに仕上げたのち、NaCl電解槽中で線状の磁区細分化溝（溝幅：0.2 mm、溝深さ：15μm 、溝間隔：３mm）を形成した。
その後、脱炭を兼ねた１次再結晶焼鈍を施したのち、MgＯ：100 重量部に対して塩化鉛を0.15重量部添加した焼鈍分離剤を、水スラリーで塗布し、焼き付け乾燥後、 800℃までをAr雰囲気中で平均30℃/hの速度で昇温し、 800℃から 900℃を（25%N₂+75%H₂)の混合雰囲気中で平均 6.5℃/hの速度で昇温し、引き続き1000℃までを平均15℃/hの速度で昇温し、雰囲気を水素雰囲気（水素分圧：1.0 atm)に切り替えて平均15℃/hの速度で1200℃まで昇温し、その後1.02気圧の水素中で1200℃, ４時間の純化焼鈍を兼ねた二次再結晶焼鈍を施したのち、放冷して、フォルステライト被膜のない方向性珪素鋼板を得た。
【００６２】
かくして得られた方向性珪素鋼板の｛１１０｝面の板面と成す角度の平均値は5.8 °であり、鋼板表面の粗度はRa＝0.29μm 、残留炭化物は５ ppm、硫化物は１ ppm、Se化物は主にMnSeで３ ppmで、（Ｃ＋Ｓ＋Se）合計で約９ ppmであり、またＷ h _17/50 ＝0.28 W/kg 、Ｗ_17/50 ＝0.62 W/kg であった。
【００６３】
【発明の効果】
かくして、この発明によれば、フォルステライト被膜を形成させることなく製造して得た方向性珪素鋼板について、ヒステリシス損を効果的に低減することができ、ひいては従来に比べ鉄損特性が一層改善された方向性珪素鋼板を安定して得ることができる。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a grain-oriented silicon steel sheet suitable as a core material for transformers, generators, etc.About grain-oriented silicon steel sheet obtained by manufacturing without forming a forsterite film,The present invention intends to further improve the iron loss characteristic by effectively reducing the hysteresis loss (hysteresis loss).
[0002]
[Prior art]
A grain-oriented electrical steel sheet containing Si and having a crystal orientation in the (110) [001] orientation or the (100) [001] orientation has excellent soft magnetic properties, so that it can be used as various iron core materials in the commercial frequency range. Widely used. The characteristics required for such an electrical steel sheet include iron loss (generally, loss when magnetized to 1.7 T at a frequency of 50 Hz)_17/50 (Expressed in (W / kg)) is important.
[0003]
In order to reduce iron loss, effective methods for reducing eddy current loss (We) include a method of increasing the electrical resistance by containing Si, a method of reducing the plate thickness, and a method of reducing the crystal grain size. On the other hand, as an effective method for reducing the hysteresis loss (Wh), a method of highly aligning the <100> axis in the rolling direction is known.
[0004]
Of these, the Si-containing method has a limit because it causes a decrease in saturation magnetic flux density and causes an increase in the size of the iron core if excessively contained, and the method of reducing the plate thickness significantly increases the manufacturing cost. After all, there was a limit.
Furthermore, the method of aligning the crystal orientation is also the magnetic flux density B₈ Products with high values of 1.96T and 1.97T have already been obtained, and there is little room for further improvement.
[0005]
In addition, in recent years, a technology has been developed to reduce the iron loss by introducing a plasma jet or laser light to introduce strain locally on the steel sheet surface or artificially subdividing the magnetic domain width by forming grooves. The iron loss can be reduced. However, there is a limit to the effect of reducing iron loss by this technology.
[0006]
Apart from these methods, Japanese Patent Publication No. 52-24499 discloses that the iron loss of the material is greatly reduced by reducing the roughness of the interface between the metal surface of the steel sheet and the non-metal coating and applying tension treatment. It has been reported to do.
[0007]
Furthermore, with regard to the annealing separator used at the time of secondary recrystallization annealing of the grain-oriented silicon steel sheet, in the annealing separator mainly composed of MgO, a dense film mainly composed of forsterite is formed on the surface of the steel sheet after annealing. Not only is the roughness of the steel sheet metal surface formed not reduced, but also inconveniences occur in the subsequent mirror polishing and thermal etching to obtain a mirror surface.
In order to prevent the formation of such a film having forsterite as a main component, for example, Japanese Patent Application Laid-Open No. 7-48674 discloses a method of performing secondary recrystallization annealing after removing subscales generated by primary recrystallization annealing. Proposed, but this method inevitably increases costs.
[0008]
From the above viewpoint, when manufacturing a mirror-oriented silicon steel sheet,₂O_Three An annealing separator containing chloride and an annealing separator containing chloride are used. For example, Japanese Patent Application Laid-Open No. 64-62476 discloses 2 to 40 wt.% Of MgO and alkali or alkaline earth metal chloride. A method of using a partly added annealing separator has been proposed.
[0009]
HoweverIn steel sheets that do not have a forsterite film, problems such as S and Se that are absorbed and removed by the film during secondary recrystallization annealing are inferior to purification, and carbon dioxide marks that are unavoidably contained in the separation agent. In addition, the problem of carburization due to the absorption of carbon generated by the decomposition of contaminated organic matters remains as a problem.
[0010]
[Problems to be solved by the invention]
This invention was developed in view of the above-mentioned present situation,In a process that does not form a forsterite film during secondary recrystallization annealing,It is an object of the present invention to propose a grain-oriented silicon steel sheet that effectively reduces hysteresis loss and thus achieves further improvement in iron loss characteristics.
[0011]
[Means for Solving the Problems]
Now, as a result of intensive studies to achieve the above object, the inventors have
(1) If a silicon steel material with a specific composition and an annealing separator with a specific composition are used and the temperature rise conditions and further the atmospheric conditions in the secondary recrystallization annealing process are controlled, a slight amount of chlorine compound or fluorine can be obtained. Mirror surface can be achieved stably with chemicals.
(2) In such mirror material, not only the angle between the <100> direction of the secondary recrystallized grains and the rolling direction, but also the angle between the <110> direction and the sheet width direction affects the iron loss value.
(3) Of the precipitates remaining inside the mirror steel sheet, carbides, sulfides, and selenides have a large effect on iron loss.
I got that knowledge.
The present invention is based on the above findings.
[0012]
  That is, the gist configuration of the present invention is as follows.
1. A grain-oriented silicon steel sheet produced without forming a forsterite film, containing Si: 1.5 to 7.0 mass%, and the {110} face of a crystal grain produced by secondary recrystallization on the plate surface On the other hand, the area weighted average is inclined in the range of 4 to 8 °, the surface of the steel is smooth with an arithmetic average roughness Ra of 0.4 μm or less, and the total amount of carbide, sulfide and selenide in steel is (C + S + Se) Less than 35 ppm and hysteresis loss Wh_17/50Satisfying 0.35 W / kg or lessWhoOriented silicon steel sheet.
  Therefore, the grain-oriented silicon steel sheet of the present invention is limited to the grain-oriented silicon steel sheet produced without forming the forsterite film.
[0013]
2. In 1 above, the surface of the steel sheet is provided with a tension insulation coating, and the hysteresis loss Wh_1.7Is 0.30 W / kg or lessWhoOriented silicon steel sheet.
[0014]
3. In the above 1 or 2, a linear or point-like strain-added region or groove forming region for magnetic domain subdivision is introduced on the steel sheet surface.WhoOriented silicon steel sheet.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described below.
First, the experimental results that led to the invention will be described.
Experiment 1
C: 0.05 mass%, Si: 3.2 mass%, Mn: 0.06 mass%, S: 0.02 mass%, Se: 0.001 mass%, Al: 0.02 mass%, N: 80 ppm and Cu: 0.2 mass%, The remainder is a slab composed of Fe and unavoidable impurities, heated to 1400 ° C, hot rolled into a 2.0 mm thick hot rolled sheet, then warm rolled to a 0.21 mm thick, and then decarburized. The primary recrystallization annealing was also performed.
[0016]
Next, an annealing separator added with various chlorides or fluorides shown in Table 1 with respect to 100 parts by weight of MgO was applied as a water slurry, baked and dried, and then subjected to secondary recrystallization under the same conditions as shown in Table 1. Annealed.
In the temperature range of 1000 ° C. or higher, the temperature was raised to 1200 ° C. at a rate of 10 ° C./h, and a secondary recrystallization finish annealing was performed at the same temperature for 6 hours of purification.
The product plate thus obtained has its surface crystal orientation, mirrored state, precipitation amount of carbide, sulfide and selenide, and hysteresis loss when magnetized to 1.7T at 50Hz (W h _17/50 Table 2 shows the results of the investigation on ().
[0017]
The crystal orientation on the surface of the product plate is expressed by an area weighted average which is the average of the angles of the {110} planes of the crystal grains with respect to the plate surface. This is because, according to this display, not only the angle between the <100> direction of the secondary recrystallized grains and the rolling direction but also the angle between the <110> direction and the sheet width direction can be expressed simultaneously. .
Here, the area weighted average is obtained by Laue's method for the orientation of each point of 5 pieces of 5 processed products under the same condition, with respect to 40 points of 5 × 8 grids at 2 cm intervals on each product, {110} The minimum angle formed between the surface and the plate surface was calculated, and the total values obtained were averaged.
Of course, about several tens of secondary grains may be selected, and an area weighted average may be obtained from their area and orientation.
[0018]
Further, the precipitation amount of carbide, sulfide and selenide [expressed by the precipitation weight of (C + Se + S)] indicates the degree of purification of the steel sheet. The smaller the amount, the less harmful elements in the steel and the less the purification of the steel sheet. It can be said that it is progressing,Precipitation is likely to occur in steel sheets produced by a process that does not form a forsterite film.In particular, since a deposited state is harmful, it is necessary to control the amount of precipitation by using a precipitation quantitative method (which may be arbitrary).
[0019]
[Table 1]

[0020]
[Table 2]

[0021]
  As apparent from the table, by adding a small amount of thallium or lead chloride or fluoride to the annealing separator and gradually heating the temperature range of 800 to 900 ° C., a {110} face plate The angle to the surface4Not only can it be controlled within an appropriate range of ~ 8 °, but also a stable mirror surface is achieved and the purification of the steel sheet is promoted, resulting in hysteresis loss (Wh_17/50) Could be effectively reduced.
  In particular, when the hydrogen partial pressure at 1000 ° C. or higher is 0.9 atm or higher, the steel sheet is further purified and mirror-finished. Further, when the range at 600 to 900 ° C. is an Ar atmosphere, the forsterite film Formation is remarkably suppressed and further purification is achieved._17/50Has been achieved.
[0022]
  If the amount of addition of thallium chloride or lead chloride is less than 0.1 parts by weight, the formation of forsterite film becomes prominent, and a mirror surface of Ra ≦ 0.4 μm cannot be obtained stably, while the amount added is 10 parts by weight. If the temperature rise rate in the temperature range of 800 to 900 ° C exceeds 8 ° C / h, the angle of the {110} plane with respect to the plate surface is stabilized.4As a result, it was not possible to obtain a low history loss as good as expected in the present invention.
[0023]
Further, according to the study by the inventors, the angle of the {110} plane with respect to the plate surface has a strong correlation with the amount of S and Se as inhibitor forming elements, and suppresses the amount of S to less than 0.005 mass%, while Se Limit the amount to the range of 0.01-0.03mass%Is preferred.
[0024]
Experiment 2
A grain oriented silicon steel sheet having substantially no forsterite coating was produced in the same manner as in Experiment 1 except that the S content and Se content were S: 0.002 mass% and Se: 0.02 mass%, respectively.
At this time, the additives and secondary recrystallization annealing conditions added to the annealing separator are as shown in Table 3.
Table 4 shows the results of the same investigation as in Experiment 1 for the product plate thus obtained.
[0025]
[Table 3]

[0026]
[Table 4]

[0027]
As shown in Table 4, while suppressing the amount of S added as an inhibitor-forming element and adding an appropriate amount of Se, the angle of the {110} plane after secondary recrystallization with respect to the plate surface is 4 to 6 °. As a result, the hysteresis loss could be stably reduced.
Even in this case, the hydrogen partial pressure at 1000 ° C. or higher should be 0.9 atm or higher, and the range from 600 to 900 ° C. should be Ar atmosphere.W h _17/50 It was still advantageous in terms of conversion.
[0028]
According to the present invention, {110} is obtained by adding a small amount of thallium or lead chloride or fluoride to the annealing separator and gradually heating the temperature range of 800 to 900 ° C. during the secondary recrystallization heating process. Not only is the orientation of the surface precisely controlled, but the mechanism by which the steel plate surface is smoothed to reduce harmful components such as carbides has not yet been clearly clarified, but thallium or lead and chlorine or fluorine elements The surface energy of the {110} plane changes due to the synergistic action with the above, or influences the grain boundary moving speed during secondary recrystallization, and promotes the growth of secondary recrystallized grains with a specific orientation. This is considered to be because the main orientation of the secondary recrystallized grains is determined by the action, and purification is also promoted during such grain boundary movement.
[0029]
  Next, in the grain-oriented silicon steel sheet of the present invention, the reason why the constituent requirements are limited to the above range will be described.
  The grain-oriented silicon steel sheet of the present invention is limited to the grain-oriented silicon steel sheet obtained by manufacturing without forming a forsterite film.
  The component composition is as follows.
Si: 1.5 to 7.0 mass%
  Si is an effective component for increasing the electrical resistance of steel sheets and reducing iron loss. However, if the content exceeds 7.0 mass%, it becomes hard and difficult to process, while if it is less than 1.5 mass%, it is difficult to process. Since a stable secondary recrystallized structure could not be obtained due to transformation during secondary recrystallization annealing, the Si content was limited to a range of 1.5 to 7.0 mass%.
  In addition, all elements such as C, S, Se and N in the product plate have a harmful effect on the magnetic properties, and particularly deteriorate iron loss. Therefore, in the product plate, C: 0.003 mass% or less, Although it is desirable to reduce S, Se: 0.002 mass% or less and N: 0.002 mass% or less, as described later, in the present invention, it is particularly important to reduce the total amount of precipitates to a predetermined amount or less. .
[0030]
Angle of {110} plane to plate surface:4~ 8 °
  This rule is particularly important in the present invention. For the crystal grains after secondary recrystallization, the {110} plane is an area weighted average with respect to the plate plane.4It is important to tilt it by ~ 8 °.
  This is not only due to the conventionally known magnetic domain refinement effect due to the change in inclination between the rolling direction and the <100> axis, but also the angle formed between the <110> axis perpendicular to the rolling direction and the plate surface causes hysteresis loss. This is because it has a great influence, and this effect is particularly great in a mirror-finished steel sheet that does not have irregularities due to a forsterite film or its anchor.
  Here is the angle4If it is less than 0 ° or exceeds 8 °, the low iron loss as expected in the present invention cannot be obtained.
[0031]
Surface roughness Ra: 0.4 μm or less
When the surface roughness Ra exceeds 0.4 μm, not only disadvantages such as deterioration of hysteresis loss occur, but also harmful components such as carbides described later increase, and reduction of iron loss cannot be achieved.
Therefore, in the present invention, the surface roughness Ra of the steel plate is limited to 0.4 μm or less.
[0032]
The total amount of carbides, sulfides and selenides is 35 ppm or less by weight (C + S + Se)
Precipitates such as carbides, sulfides, and selenides are harmful components that inhibit the domain wall movement and deteriorate hysteresis and iron loss, so it is preferable to reduce them as much as possible. acceptable.
[0033]
W h _17/50 : 0.35 W / kg or less
In the present invention, as described above, the angle of the {110} plane with respect to the plate surface is controlled in the range of 2 to 8 °, the surface roughness Ra is 0.4 μm or less, and the (C + S + Se) amount is 35 ppm or less. LowW h _17/50 Has been difficult to achieve in the past.W h _17/50 ≤0.35 W / kg is listed as a feature item.
[0034]
In addition, in the present invention, by applying a tension coating, it can be effectively performed with a slight tension.W h _17/50 Can be reduced to 0.30 W / kg or less.
Furthermore, in the present invention, the iron loss can be further reduced by performing a magnetic domain subdivision process such as formation of a linear or dotted strain added region or groove during or after the manufacturing process.
The plate thickness of the steel plate is not particularly limited, but the classical eddy current loss of eddy current loss is a function of the plate thickness. Usually, it is preferably about 0.10 to 0.25 mm.
[0035]
Next, the manufacturing method of the grain-oriented electrical steel sheet of this invention is demonstrated.
First, the component composition range of a raw material is demonstrated.
Si: 1.5 to 7.0 mass%
As explained for the grain-oriented electrical steel sheet, which is a product, if the content is less than 1.5 mass%, transformation occurs during secondary recrystallization annealing and a stable secondary recrystallization structure cannot be obtained, while 7.0 mass% is reduced. If it exceeds, it becomes hard and processing becomes difficult, so the Si content is limited to the range of 1.5 to 7.0 mass%.
[0036]
Al: 0.06 mass% or less, N: 0.01 mass% or less
Al combines with N to form AlN useful as an inhibitor. In particular, the crystal orientation can be further improved by containing 0.006 mass% or more of Al in the initial steel. However, if the content exceeds 0.06 mass%, the crystal orientation deteriorates again, so Al is limited to 0.06 mass% or less.
Moreover, since generation | occurrence | production of a blister defect will be anxious when N content exceeds 0.01 mass%, N amount was limited to 0.01 mass% or less. Although the lower limit is not specified, it is economically disadvantageous to reduce it to 20 ppm or less.
[0037]
Se and / or S: 0.01 to 0.06 mass%, Mn: 0.02 to 0.2 mass%
Se, S and Mn combine with each other to form the inhibitors MnSe, MnS. In order to secure an appropriate amount of MnSe and MnS here, 0.01 mass% or more and 0.06 mass% or less and Mn: 0.02 to 0.2 mass% are indispensable in the sum of (Se + S) in the initial steel. The reason is that if these amounts are less than the lower limit, the amount of the inhibitor for suitably causing secondary recrystallization is insufficient, while if the upper limit is exceeded, solid solution before hot rolling becomes difficult. .
As will be described later, in the case of performing a nitrogen increase treatment after the final cold rolling and before the secondary recrystallization annealing, the addition of Se, S and Mn is not necessarily required. It is preferable to add for the purpose of improving ductility.
[0038]
In addition, as described in Experiment 2, the S and Se amounts have a strong correlation with the angle of the {110} plane with respect to the plate surface, and in order to control this angle within a suitable range of 4 to 6 °, the S amount Is preferably limited to less than 0.005 mass%, and the Se content is preferably limited to a range of 0.01 to 0.03 mass%.
[0039]
At least one selected from B, Bi, Sb, Mo, Te, Sn, P, Ge, As, Nb, Ni, Cr, Ti, Cu, Pb, Zn and In: 0.0005 to 2.0 mass%
All of these elements are added for the purpose of controlling secondary recrystallization orientation by segregation to the surface and grain boundaries, precipitate formation, etc., but if the content does not reach 0.0005 mass%, The addition effect is poor, and on the other hand, if it exceeds 2.0 mass%, the decrease in the magnetic east density is caused. Therefore, in either case of single use or combined use, it is included in the range of 0.0005 to 2.0 mass%.
[0040]
Furthermore, in the present invention, C can be contained in the initial steel in the range of about 0.0050 to 0.08 mass% for the purpose of promoting recrystallization during hot rolling and improving magnetic properties.
[0041]
Next, a specific manufacturing process will be described.
A steel ingot or slab adjusted to a predetermined component is subjected to hot rolling and cold / warm rolling to a final thickness by a known method. Steel materials include continuous hot rolling and sheet bar casting,stripWhat was obtained by the casting method etc. can also be applied.
[0042]
Next, secondary recrystallization annealing is performed after the primary recrystallization annealing. In the present invention, nitrogen increase treatment can be performed after the final cold rolling and before the secondary recrystallization annealing.
This treatment is performed in order to increase the nitrogen concentration on the surface of the steel sheet and strengthen the inhibitor function by AlN during secondary recrystallization.
Therefore, when this treatment is performed, a high-temperature heat treatment for dissolving AlN in the slab stage is not necessarily required, and there is an advantage that the slab heating temperature can be reduced to about 1280 ° C. or less.
[0043]
When the secondary recrystallization annealing is performed, an annealing separator is applied to the surface of the steel plate prior to the second recrystallization annealing. In this invention, a thallium or lead chlorine compound or a fluorine compound is contained in the annealing separator. CanSuitableIt is.
This is because these thallium or lead chlorine compounds or fluorine compounds can control the angle of the {110} plane with respect to the plate surface to an appropriate range with a small amount of addition, as described in Experiment 1, and can be made into a stable mirror surface. And purification is achieved, resulting in hysteresis loss (W h _17/50 ) Can be effectively reduced.
[0044]
Here, the amount of thallium or lead chlorine compound or fluorine compound added is 0.1 to 10 parts by weight with respect to 100 parts by weight of the normal annealing separator.Is preferable. This is because if the amount is less than 0.1 parts by weight, the effect of addition is poor. On the other hand, if it exceeds 10 parts by weight, there is a concern about corrosion of the furnace body and rusting on the product plate due to chloride, although it is less than conventional parts. It is.
The main component of the annealing separator is MgO or A1.₂O_Three Any conventionally known one can be used.
As a coating method, a known method such as electrostatic coating or water slurry coating can be used. About application amount 3-30 g / m² The degree is preferred.
Further, the above separating agent can be supplemented by adding metal chloride, hydroxide, borate, nitrate, phosphate, carbonate, sulfate and sulfide as appropriate.
[0045]
Next, after applying an annealing separator containing an appropriate amount of a thallium or lead chlorine compound or fluorine compound as described above to the steel sheet surface, secondary recrystallization annealing is performed. During this secondary recrystallization annealing step, In particular, during the heating process, the heating rate from 800 ° C to 900 ° C should be gradually heated to 8 ° C / h or less.preferable.
This is because the orientation stability of the secondary recrystallization decreases when the heating rate at 800 to 900 ° C. exceeds 8 ° C./h.
[0046]
Thus, it is possible to obtain a grain-oriented silicon steel sheet in which the forsterite film is substantially not formed, the precipitation of carbides and the like is small, and the orientation of the {110} plane is precisely controlled.
[0047]
By the way, in this invention, in order to further promote the mirror finishing and purification of the steel sheet surface, it is desirable that the hydrogen partial pressure at 1000 ° C. or higher is 0.9 atm or higher.
This is because when the hydrogen partial pressure at 1000 ° C. or higher is 0.9 atm or higher, the formation of surface oxides is suppressed, and H₂S or H₂This is because the effective vaporization of Se further promotes the mirroring and purification of the steel sheet surface.
[0048]
Further, if the range at 600 to 900 ° C. is used as an Ar atmosphere, the formation of the forsterite film is remarkably suppressed, and further mirror finishing and purification are achieved.
In this respect, formation of a precursor oxide of a film such as forsterite is promoted in a widely used nitrogen atmosphere.
Therefore, in this case, there is an advantage that the desired object can be achieved even if the amount of chloride added to the annealing separator is small.
Here, the Ar atmosphere described above does not necessarily have to be performed over the entire temperature range from 600 ° C. to 900 ° C., and may be a partial temperature range of this temperature range.
[0049]
In addition, in this invention, after mirror-finishing by secondary recrystallization annealing as described above, it is possible to combine with other known methods such as further smoothing the surface by NaC1 electrolysis or the like.
Further, in the present invention, it is possible to further reduce the iron loss by forming a tension coating on the surface of the mirror-oriented silicon steel plate obtained as described above.
Here, as the tension coating, any conventionally known coating such as a phosphate coating and a ceramic coating by PVD or the like is suitable.
Furthermore, the present invention can be used in combination with the conventional magnetic domain refinement technique, and a synergistic effect more than additive can be obtained by the combined use. The magnetic domain subdivision technology mentioned here is, for example, a method of locally irradiating a steel plate surface of a product with a laser or plasma jet, a method of providing a strained region, a method of providing grooves on the steel plate surface, a structure or composition of the steel plate surface, Including the method of locally changing including the conventional methods such as a protrusion roll and an etching method can be applied in actual processing.
[0050]
【Example】
Example 1
C: 0.05 mass%, Si: 3.2 mass%, Mn: 0.06 mass%, S: 0.03 mass%, A1: 0.02 mass%, N: 80 ppm, Sn: 0.3 mass% and Cu: 0.2 mass%, The remainder is a slab consisting of Fe and inevitable impurities, heated to 1370 ° C, hot-rolled into a 2.0 mm thick hot-rolled sheet, and then warm-rolled to a final thickness of 0.21 mm First recrystallization annealing that also serves as decarburization was performed.
This steel plate is divided into two, one side is A1₂0_Three: An annealing separator with 0.15 parts by weight of lead fluoride added to 100 parts by weight (invention example), the other being A1₂0_ThreeA single annealing separator (comparative example), 18 g / m each by electrostatic application²Apply and N up to 800 ℃₂Increase the temperature in the atmosphere at an average rate of 50 ° C / h, and increase from 800 ° C to 900 ° C (25% N₂+ 75% H₂) In a mixed atmosphere at an average rate of 4.5 ° C / h, and then heated up to 1200 ° C in a hydrogen + nitrogen mixed atmosphere (hydrogen partial pressure: 0.8 atm) at an average rate of 14 ° C / h. Subsequently, secondary recrystallization finish annealing was performed at 1200 ° C. for 6 hours, followed by cooling to obtain a grain-oriented silicon steel sheet without a forsterite coating.
[0051]
The average value (area weighted average) of the angles formed with the {110} face of the grain-oriented silicon steel sheet thus obtained was 4.6 ° in the invention example, and 9.9 ° in the comparative example.
The roughness of the steel sheet surface was Ra: 0.32 μm in the inventive example and Ra: 0.45 μm in the comparative example.
Furthermore, in the invention example, the amount of residual carbide is 8 ppm, and sulfide is mainly Cu.₂S is 22 ppm, Se compound is mainly MnSe 3 ppm, (C + S + Se) total 33 ppm, andW h _17/50 = 0.33 W / kg, while the comparative examples were 15 ppm, 35 ppm, and 5 ppm, respectively, and (C + S + Se) was 55 ppm in total.W h _17/50 = 0.51 W / kg.
[0052]
In addition, when the hydrogen partial pressure in the temperature range of 1000 ° C. or higher is raised to 1.0 atm during the manufacturing process for the above invention example, the average value of the angle formed with the {110} plane is 3.8 °, and the steel plate Surface roughness of Ra: 0.29 μm, (C + S + Se) total: 26 ppm,W h _17/50 = Good hysteresis loss of 0.30 W / kg was obtained.
[0053]
Further, in the above manufacturing process, when the temperature rising atmosphere up to 800 ° C. was Ar atmosphere, the average value of the angle formed with the {110} plane was 4.5 °, and the surface roughness of the steel plate was Ra: 0.26 μm, (C + S + Se) total: 23 ppm,W h _17/50 A better hysteresis loss of 0.28 W / kg was obtained.
[0054]
Example 2
Si: 3.2 mass%, Mn: 0.06 mass%, Al: 0.02 mass%, N: 80 ppm, Sb: 0.1 mass% and Bi: 0.0005 mass%, the balance being a slab composed of Fe and inevitable impurities, After heating to 1150 ° C., a hot-rolled sheet having a thickness of 2.0 mm was formed by hot rolling, and after hot-rolled sheet annealing, the sheet was finished to a thickness of 0.29 mm by cold rolling, followed by primary recrystallization annealing.
Then H₂+ N₂+ After annealing at 800 ° C for 1 min in a mixed ammonia atmosphere, an annealing separator containing 6 parts by weight of thallium chloride with respect to 100 parts by weight of MgO is 14 g / m in water slurry.²After applying and drying, N up to 800 ° C₂Increase the temperature at an average rate of 50 ° C / h in the atmosphere, and increase the temperature from 800 ° C to 900 ° C (25% N₂+ 75% H₂) At an average rate of 4.5 ° C / h, and an increase from 900 ° C to 1150 ° C at an average rate of 20 ° C / h in a hydrogen + nitrogen mixed atmosphere (hydrogen partial pressure: 0.8 atm). Then, after subjecting to secondary recrystallization finish annealing in hydrogen at 1150 ° C. for 6 hours, it was allowed to cool to obtain a grain-oriented silicon steel sheet having no forsterite coating.
[0055]
The average value of the angle formed with the {110} face of the directional silicon steel sheet thus obtained is 3.2 °, the steel sheet has a surface roughness of Ra: 0.25 μm, the residual carbide content is 16 ppm, and the sulfide is mainly used. In addition, MnS is 8 ppm, Se is mainly Cu.₂Se at 4 ppm, (C + S + Se) total 28 ppm, andW h _17/50 = 0.33 W / kg.
[0056]
In addition, when the hydrogen partial pressure in the temperature range of 1000 ° C. or higher is raised to 1.02 atm during the above treatment, the average value of the angle formed with the {110} plane is 4.1 °, and the surface roughness of the steel plate is Ra: 0.22 μm, (C + S + Se) total: 22 ppm,W h _17/50 = Good hysteresis loss value of 0.25 W / kg was obtained.
[0057]
Further, during the above treatment, when the temperature rising atmosphere up to 800 ° C. was Ar atmosphere, the average value of the angle formed with the {110} plane was 4.4 °, the surface roughness of the steel plate was Ra: 0.20 μm, ( C + S + Se) Total: 18 ppm,W h _17/50 A better hysteresis loss of 0.23 W / kg was obtained.
[0058]
Example 3
C: 0.06 mass%, Si: 3.2 mass%, Mn: 0.06 mass%, S: 0.002 mass%, Se: 0.02 mass%, Al: 0.03 mass%, N: 90 ppm, Sb: 0.07 mass%, Cu: 0.2 slab containing mass% and Ni: 0.1 mass%, the balance being Fe and inevitable impurities, induction-heated to 1410 ° C, hot rolled into 2.0mm hot rolled sheet, and then after hot rolled sheet annealing After finishing by cold rolling and warm rolling followed by intermediate annealing to a sheet thickness of 0.19mm, linear magnetic domain subdivision grooves (groove width: 0.2mm, groove depth: 15μm, groove spacing in NaCl electrolytic cell : 3 mm).
Then, after performing primary recrystallization annealing also used for decarburization, an annealing separator added with 0.15 parts by weight of lead chloride with respect to 100 parts by weight of MgO was applied in a water slurry, baked and dried, then 800 ° C Up to 800 ° C to 900 ° C in Ar atmosphere at an average speed of 6.5 ° C / h, then in a hydrogen atmosphere of 1.02 atm The temperature is increased to 1200 ° C at a rate of 10 ° C / h, and after this, secondary recrystallization annealing is performed for 4 hours of purification, and then left to cool to obtain a grain-oriented silicon steel sheet without forsterite coating. It was.
[0059]
The average angle formed with the {110} face of the grain-oriented silicon steel sheet thus obtained is 5.2 °, the roughness of the steel sheet surface is Ra: 0.19 μm, residual carbide is 5 ppm, and sulfide is the lower limit of analysis. Less than (1 ppm), Se compound is mainly 2 ppm in MnSe, (C + S + Se) total is about 7 ppm, andW h _17/50 = 0.21 W / kg, W_17/50 = 0.58 W / kg.
[0060]
Furthermore, when this steel plate was subjected to light pickling and electropolishing in a 0.5 μm NaCl aqueous solution on one side,W h _17/50 Reduced to 0.18 W / kg, and when tension coating by Cr plating was applied,W h _17/50 = 0.17 W / kg, W_17/50 = Good iron loss value of 0.49 W / kg was obtained.
[0061]
Example 4
Contains C: 0.06 mass%, Si: 3.2 mass%, Mn: 0.06 mass%, S: 0.001 mass%, Se: 0.03 mass%, Sb: 0.07 mass% and Mo: 0.02 mass%, the balance being Fe and inevitable A slab composed of mechanical impurities is induction-heated to 1410 ° C, and then hot-rolled into a 2.0 mm hot-rolled sheet, and after hot-rolled sheet annealing, the sheet thickness is 0.19 by warm rolling followed by cold rolling and intermediate annealing. After finishing to mm, linear magnetic domain subdivided grooves (groove width: 0.2 mm, groove depth: 15 μm, groove interval: 3 mm) were formed in a NaCl electrolytic cell.
Then, after performing primary recrystallization annealing also used for decarburization, an annealing separator added with 0.15 parts by weight of lead chloride with respect to 100 parts by weight of MgO was applied in a water slurry, baked and dried, then 800 ° C Up to an average temperature of 30 ° C / h in an Ar atmosphere to 800 ° C to 900 ° C (25% N₂+ 75% H₂) In the mixed atmosphere at an average rate of 6.5 ° C / h, then up to 1000 ° C at an average rate of 15 ° C / h, and switching the atmosphere to a hydrogen atmosphere (hydrogen partial pressure: 1.0 atm) The temperature was raised to 1200 ° C at an average rate of 15 ° C / h, and then subjected to secondary recrystallization annealing that also served as purification annealing at 1200 ° C for 4 hours in 1.02 atmospheres of hydrogen, then left to cool, and forsterite A grain-oriented silicon steel sheet without a coating was obtained.
[0062]
The average angle formed with the {110} face of the directional silicon steel sheet thus obtained is 5.8 °, the roughness of the steel sheet surface is Ra = 0.29 μm, the residual carbide is 5 ppm, and the sulfide is 1 ppm. Se compounds are mainly 3 ppm for MnSe and about 9 ppm in total for (C + S + Se), andW h _17/50 = 0.28 W / kg, W_17/50 = 0.62 W / kg.
[0063]
【The invention's effect】
  Thus, according to the present invention,About grain-oriented silicon steel sheet obtained by manufacturing without forming a forsterite film,Hysteresis loss can be effectively reduced, and as a result, a grain-oriented silicon steel sheet having further improved iron loss characteristics as compared with the prior art can be stably obtained.

Claims (3)

A grain oriented silicon steel sheet produced without forming a forsterite film, containing Si: 1.5 to 7.0 mass%, and the {110} face of the crystal grains produced by secondary recrystallization on the plate surface On the other hand, the area weighted average is inclined in the range of 4 to 8 °, the surface of the steel is smooth with an arithmetic average roughness Ra of 0.4 μm or less, and the total amount of carbide, sulfide and selenide in the steel is (C + S + Se) weight. tropism silicon steel towards you, characterized in that at 35 ppm or less, and hysteresis loss Wh _17/50 satisfies the following 0.35 W / kg in. According to claim 1, comprising a tension insulating coating on the steel sheet surface, tropic silicon steel sheet towards you, wherein the hysteresis loss Wh _17/50 is not more than 0.30 W / kg. According to claim 1 or 2, the surface of the steel sheet, a linear or tropic silicon steel towards you, characterized in that the introduction of point-like distortion additional area or the groove forming region for domain refining.