JPH04289121A - Production of thin grain-oriented silicon steel sheet having stable magnetic property - Google Patents
Production of thin grain-oriented silicon steel sheet having stable magnetic propertyInfo
- Publication number
- JPH04289121A JPH04289121A JP3074365A JP7436591A JPH04289121A JP H04289121 A JPH04289121 A JP H04289121A JP 3074365 A JP3074365 A JP 3074365A JP 7436591 A JP7436591 A JP 7436591A JP H04289121 A JPH04289121 A JP H04289121A
- Authority
- JP
- Japan
- Prior art keywords
- annealing
- hot
- rolling
- rolled
- silicon steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910000976 Electrical steel Inorganic materials 0.000 title claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 238000000137 annealing Methods 0.000 claims abstract description 60
- 238000005096 rolling process Methods 0.000 claims abstract description 35
- 238000005097 cold rolling Methods 0.000 claims abstract description 24
- 230000009467 reduction Effects 0.000 claims abstract description 15
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 9
- 239000010959 steel Substances 0.000 claims abstract description 9
- 238000005261 decarburization Methods 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 9
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 5
- 238000005098 hot rolling Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 14
- 238000001953 recrystallisation Methods 0.000 abstract description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 8
- 230000002159 abnormal effect Effects 0.000 abstract description 6
- 239000011162 core material Substances 0.000 abstract description 3
- 239000000047 product Substances 0.000 description 12
- 238000002474 experimental method Methods 0.000 description 6
- 239000007858 starting material Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 230000004907 flux Effects 0.000 description 4
- 239000003112 inhibitor Substances 0.000 description 4
- 229910052711 selenium Inorganic materials 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 238000005554 pickling Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 229910052718 tin Inorganic materials 0.000 description 3
- 238000009749 continuous casting Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000000265 homogenisation Methods 0.000 description 2
- 238000003303 reheating Methods 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Manufacturing Of Steel Electrode Plates (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】この発明は、主にトランスやその
他の電気機器の鉄心材料として使用される方向性けい素
鋼板、特に板厚が０．１０〜０．２５ｍｍと薄手の方向
性けい素鋼板における磁気特性を安定化する方法に関す
る。
【０００２】
【従来の技術】この種電気機器の鉄心材料としては、磁
気特性に優れること、具体的には磁場の強さ８００ Ａ
／ｍにおける磁束密度Ｂ８ （Ｔ）が高く、また５０Ｈ
ｚの交流磁束密度１．７ Ｔにおける鉄損特性Ｗ１７／
５０ （Ｗ／ｋｇ）が低いことが要求される。このため
方向性けい素鋼板は、２次再結晶を利用して｛１１０｝
＜００１＞方位いわゆるゴス方位の結晶粒を発達させた
ものである。そして磁気特性の優れた材料を得るには、
磁化容易軸である＜００１＞軸を圧延方向に高度に揃え
ることが必要であり、適当な圧延と熱処理を組合せた諸
工程によって、ゴス方位に２次再結晶粒を安定して発達
させることが重要である。特にインヒビターと呼ばれる
ＭｎＳ， ＭｎＳｅ，ＡｌＮ等の析出物を均一かつ微細
に分散させること及び上記２次再結晶に有利な集合組織
を有することが必須条件であるのは既に知られたところ
である。
【０００３】一方低鉄損化に有利な製品厚みが０．１０
〜０．２５ｍｍの方向性けい素鋼板に対する需要も高ま
りつつあるが、板厚が薄くなるほど、安定して２次再結
晶させることが困難になり、製品の磁気特性にばらつき
が生じるため、磁気特性の安定化に問題を残していた。
【０００４】磁気特性の安定化については、２次再結晶
焼鈍の初期に高温処理してから引続き通常の焼鈍を行う
方法（特公昭５８−５５２１２ 号公報参照）や脱炭焼
鈍時に生成される酸化物量を制御する方法（特開昭６０
−１０３１７３号公報参照）、またインヒビターとして
ＡｌＮ を含む素材に関しては、脱炭焼鈍の前の工程で
０．００７０〜０．０３０ ％の脱炭を行う方法（特開
昭６１−１１７２１５号公報参照）やＳｎあるいはＣｕ
の添加を行う方法（特開平２−２０９４２７号公報参照
）等が提案されている。
【０００５】
【発明が解決しようとする課題】しかしながら、これら
の方法により磁気特性は改善されるものの、コイル全長
にわたって一定の磁気特性を付与することは難しい。特
に最終仕上焼鈍において２次再結晶粒をコイル全長にわ
たり良好に発達させることは、板厚が薄くなるほど難し
い。なぜなら板厚が薄くなるほど、２次再結晶粒の核と
なり得る｛１１０｝＜００１＞方位粒が減少するためで
ある。なおこの理由は明らかではないが、冷間圧延時の
剪断歪分布が板厚により異なるためと考えられる。ちな
みに特開昭６１−２３８９１６号公報では、集合組織改
善法としてＣＢＳ（Ｃｏｎｔａｃｔ ＢｅｎｄＳｔｒｅ
ｔｃｈ： 特殊異周速圧延法） 圧延法を開示してい
るが、このような方法は生産性が悪く実現性に乏しい。
そこでこの発明は、安定した磁気特性を有する方向性け
い素鋼板の製造方法について提案することを目的とする
。
【０００６】この発明は、Ｃ：０．０２〜０．１０ｗｔ
％（以下単に％で示す）、Ｓｉ：２．５ 〜４．０ ％
及びＭｎ：０．０３〜０．１５％を含み、さらにＳｅ及
び／又はＳを０．０１〜０．０４％含有する組成になる
鋼スラブを熱間圧延して熱延板とした後、この熱延板に
中間焼鈍を挟む２回以上の冷間圧延を施したのち、脱炭
焼鈍ついで最終仕上げ焼鈍を施す一連の工程によって方
向性けい素鋼板を製造するに当たり、該冷間圧延に先立
ち、熱延板を（ロール径）／（板厚）≧５０の圧延機に
よって圧下率：０．５ 〜１５％で圧下した後、７００
〜１１００℃の温度域での熱延板焼鈍を施すことを特
徴とする磁気特性の安定した薄手方向性けい素鋼板の製
造方法である。
【０００７】以下この発明の基礎となった実験結果を詳
細に説明する。発明者らは、中間焼鈍を挟む２回の冷間
圧延により板厚０．１０〜０．２５ｍｍの方向性けい素
鋼板の製造工程のうち、最終の冷間圧延圧下率を６５％
として、先ず中間焼鈍前の１次冷間圧延の圧下率を最適
化する試みの実験を行った。実験は、Ｃ：０．０４５
％、Ｓｉ：３．３５％、Ｍｎ：０．０８０ ％、Ｓ：０
．０２５ ％、Ｓｂ：０．０２７ ％を含む板厚１．８
ｍｍ の熱延板を出発材料とした。熱延板には、種々の
圧下率で予備の冷間圧延（以下予備圧延と示す）して板
厚を種々に変化させた後、それぞれに１０００℃で３０
ｓの均一化焼鈍を施したものを用いた。そしてこれらの
板厚の異なる素材を冷間圧延によりすべて０．４ｍｍ
厚に仕上げ、９５０ ℃で６０ｓの中間焼鈍後０．１４
ｍｍ厚まで冷間圧延し、次いで８５０ ℃で２分間の脱
炭焼鈍を行い、引き続きＭｇＯを主成分とする分離剤を
塗布後、最終仕上焼鈍を行った。
得られた製品の磁気特性について調べた結果を表１に示
す。
【０００８】
【０００９】同表に示す実験結果は、中間焼鈍前の１次
冷間圧延の圧下率が７５〜７６．５％で２次再結晶が安
定して発達したことから、さらに板厚を１．７ｍｍ で
仕上げて予備圧延を施さない熱延板を出発材として、同
表Ｂに従う条件で追試実験を行ったが、異常組織の発生
により良好な磁気特性は得られなかった。したがって１
次冷延圧下率と異常組織の発生率との間に相関関係はな
く、磁気特性の向上は他の因子によるものと推察された
。
【００１０】そこで発明者らは熱延板焼鈍前の予備の冷
間圧延の影響を調べるために、さらに実験を重ねた。す
なわち出発材は上記の板厚１．７ｍｍ の熱延板とこの
熱延板を熱延板焼鈍前に予備圧延で１．５ｍｍ 厚及び
１．３ｍｍ 厚に仕上げた熱延板とを用いた。その後は
表１と同一条件で熱延板焼鈍、１次冷間圧延、中間焼鈍
、２次冷間圧延、脱炭焼鈍、そして最終仕上焼鈍して得
た製品の磁気特性について測定した結果を表２に示す。
【００１１】
【００１２】発明者らは、表１及び２の結果から、熱延
板焼鈍前の予備圧延が引起こす影響について鋭意究明し
たところ、予備圧延後１０００℃で３０秒の均一化焼鈍
を施した試料とそうでない試料との結晶組織に大きな差
があることが判った。
【００１３】通常けい素鋼熱延板の組織は、熱間圧延方
向に伸びたバンド状の未再結晶組織からなる。予備圧延
をしなかった試料Ａ，Ｆでは、熱延板焼鈍後も、このバ
ンド状組織がそのまま残存していた。また予備圧延した
試料Ｄ，Ｅ，Ｈでは、バンド状の名残りはあるものの板
厚全体を通じて再結晶粒より成っていた。ところが予備
圧延圧下率の少ない試料Ｂ，Ｃ，Ｇでは、表面から板厚
１／４程度の厚みまでは再結晶粒であり、中心層ではバ
ンド状組織という層状の組織となっていた。この理由は
明らかではないが、このような再結晶組織とバンド状組
織の構造をもつ試料の場合は、薄板製品であっても磁気
特性が安定することが判明した。
【００１４】更に予備圧延の適用範囲を定める再現実験
を繰り返したところ、使用する圧延機により効果の得ら
れない場合もあることが新たに判明した。これらの圧延
機はロール径に差があるため、さらに同一の圧延機を用
いてワークロール径を変更した実験を行った。素材は、
２．０ｍｍ 厚の熱延板とし、予備圧延に用いるロール
径を８０ｍｍφ、１５０ ｍｍφ、３００ ｍｍφ、５
００ ｍｍφの４水準に、また予備圧延圧下率を０．５
％、１％、５％、１０％、１５％、２０％、２５％とし
た予備圧延を実施し、次いで１０００℃で３０ｓの熱延
板焼鈍を施した後、１次冷間圧延の仕上厚を０．４ｍｍ
に揃えた。その後９５０ ℃で６０ｓの中間焼鈍を経
て０．１４ｍｍの最終板厚とし、さらに８５０ ℃×２
分間の脱炭焼鈍、ＭｇＯ を主成分とする焼鈍分離剤の
塗布、そして最終仕上焼鈍を施して得た製品の磁束密度
及び異常組織の発生率について調べた結果を、図１及び
表３に示す。
【００１５】
【００１６】同表の結果から、圧下率が０．５ 〜１５
％の範囲の予備圧延を行うことで異常組織の発生を回避
し得ることが判った。またロール径も再結晶挙動に影響
を与えること、すなわちロール径の大きさにより、板に
及ぼす応力状態が変わり、結果として板表層部の再結晶
挙動に差をもたらすと考えられる。これはその他の実験
結果からも明らかで、ロール径と熱延板の板厚比が５０
倍以上のとき良好な結果が得られることも判った。
【００１７】
【作用】この発明の出発材となる鋼スラブの成分組成は
、Ｃ：０．０２〜０．１０％、Ｓｉ：２．５〜４．０
％、Ｍｎ：０．０３〜０．１５％、Ｓｅ及び／又はＳ：
０．０１〜０．０４％が必要である。
以下に各成分の含有量の限定理由を説明する。Ｃ：０．
０２〜０．１０％
Ｃは、熱延時にγ変態を利用するために０．０２％以上
は必要であるが、０．１０％を越すと後工程の脱炭焼鈍
が困難となる。
Ｓｉ：２．５ 〜４．０ ％
Ｓｉは、２．５ ％より少ない場合は電気抵抗が低く鉄
損特性の向上が望めず、一方４．０ ％を越すと冷間圧
延が著しく困難となる。
Ｍｎ：０．０３〜０．１５％、Ｓｅ及び／又はＳ：０．
０１〜０．０４％ＭｎとＳｅ及びＳは、ＭｎＳｅ， Ｍ
ｎＳ を形成するために必要な元素であり、Ｍｎの適量
は０．０３〜０．１５％、Ｓｅ及び／又はＳは０．０１
％より少ないとＭｎＳｅ， ＭｎＳ の量が不足し、０
．０５％を越すと均一微細なサイズに分散析出させるこ
とが困難となる。
【００１８】なお上記成分の他にも、Ｓｂ， Ｃｕ，
Ｓｎ， Ｃｒ， Ｎｉ及びＭｏ等公知の元素を１種ある
いは複合で含むことは問題ない。これらの元素の添加量
の許容最高値は、Ｃｕ， Ｓｎ，Ｃｒ， Ｎｉは０．３
％、Ｓｂ， Ｍｏは０．０５％である。すなわちＣｕ
， Ｓｎ， Ｃｒ， Ｎｉ等については、０．３ ％を
越すと磁気特性が劣化するだけでなく、酸洗性、脱炭性
が悪くなり好ましくない。またＳｂ， Ｍｏについても
０．０５％を越すと著しく脱炭性を阻害するため好まし
くない。
【００１９】上記成分組成になる溶鋼は、常法に従う製
鋼及び鋳造工程にてスラブとなし、１３５０℃以上の高
温でインヒビター成分の溶体化処理を施したのち、熱間
圧延により熱延板とする。次いで熱延板焼鈍後に中間焼
鈍を挟む２回以上の冷間圧延を行うが、それぞれ圧下率
は３０〜８０％が適当である。
【００２０】ここで熱延板焼鈍に先立ち、圧延機のワー
クロール径 （ｍｍ） と熱延板の板厚 （ｍｍ） の
比が５０倍以上である圧延機により、全圧下率で０．５
〜１５％の圧延を１回あるいは複数パスで施すこと、
その後７００ 〜１１００℃で短時間の熱延板焼鈍を行
って冷間圧延前の結晶組織を板厚方向で制御することが
肝要である。熱延板焼鈍は、上記予備圧延した熱延板の
表面層を再結晶させるために７００ ℃以上にする必要
があり、一方１１００℃を越えるとＭｎＳｅ， ＭｎＳ
等の析出物が粗大成長して、インヒビター機能が損わ
れるので好ましくない。時間については、再結晶を目的
としているので、該温度に到達すればよく、焼鈍を安定
して行なえる条件範囲で短くても問題ない。
【００２１】
【実施例】実施例１
表４に示す組成になる溶鋼を連続鋳造によりスラブとし
、１４３０℃で１５分の高温再加熱後、板厚２．７ｍｍ
の熱延板とした。この熱延板にワークロール径９００
ｍｍφのスキンパスミルを用いて２パス合計で８％の
圧延を施した。また比較として、同一組成の別コイルに
ワークロール径８５ｍｍφのゼンジマーミルを用いて２
パス合計で８％の圧延を施した。その後１０００℃で１
５ｓの熱延板焼鈍・酸洗を経て１回目の冷間圧延を行な
い０．７８ｍｍの板厚に仕上げた。
さらに中間焼鈍として昇温時に軽脱炭を施し、１０００
℃で６０ｓの均熱後、引続き室温まで急冷した。その後
２回目の冷間圧延で最終板厚０．３０ｍｍに仕上げ、さ
らに湿水素雰囲気で８５０ ℃で３分間の脱炭焼鈍を施
した後ＭｇＯ を主成分とした焼鈍分離剤を塗布してか
ら、２次再結晶焼鈍、そして仕上焼鈍を施した。かくし
て得られた製品の磁気特性について調べた結果を表５に
示すように、この発明の適用により、良好な磁気特性が
得られた。
【００２２】
【００２３】
【００２４】実施例２
Ｃ：０．０４％、Ｓｉ：３．３５％、Ｍｎ：０．０７％
、Ｓｅ：０．０２１ ％、Ｓｂ：０．０２７ ％、Ｃｕ
：０．０６％を含む組成の鋼スラブを１４３０℃で２０
分加熱後、熱間圧延して板厚１．８ｍｍ に仕上げたコ
イルと、同一組成の熱延板をワークロール径８５０ ｍ
ｍφのスキンパス圧延機、ワークロール径３５０ ｍｍ
φのタンデム圧延機、ワークロール径９０ｍｍφのゼン
ジマー圧延機でそれぞれ合計で１０％の予備圧延を施し
たコイルを用意した。その後９００ ℃で１００ ｓの
熱延板焼鈍を施し、冷間圧延により０．５ｍｍ 厚に仕
上げた。次いで９５０ ℃で６０ｓの中間焼鈍を施して
から室温まで急冷し、２回目の冷間圧延で０．２０ｍｍ
厚に仕上げた。さらに８５０ ℃で２分間の脱炭焼鈍を
施した後ＭｇＯ を主成分とした焼鈍分離剤を塗布して
から、２次再結晶焼鈍し、仕上焼鈍を施した。かくして
得られた製品の磁気特性について調べた結果を表６に示
すように、この発明の適用により、良好な磁気特性が得
られた。
【００２５】
【００２６】実施例３
表７に示す溶鋼を連続鋳造によりスラブとし、１４３０
℃で２０分の高温再加熱後、板厚１．８ｍｍ と１．４
ｍｍ の熱延板とした。この熱延板にワークロール径６
００ ｍｍφのスキンパスミルを用いて１パスで圧下率
５％の圧延を施した。また比較として、同一組成の別コ
イルをワークロール径８０ｍｍφのゼンジマーミルを用
いて１パスで圧下率５％の圧延を施した。その後１００
０℃で３０ｓの熱延板焼鈍を施した後酸洗を行い、次い
で１回目の冷間圧延にて、１．８ｍｍ 厚の熱延板を出
発材にしたものは（Ａ）０．６ｍｍ 厚と（Ｂ） ０．
４ｍｍ 厚に仕上げ、１．４ｍｍ厚の熱延板を出発材に
したものは（Ｃ）０．３ｍｍ 厚に仕上げた。引き続き
９５０ ℃×６０ｓの中間焼鈍後に２回目の冷間圧延を
行い（Ａ） ０．２３ｍｍ、（Ｂ） ０．１５ｍｍ、（
Ｃ） ０．１０ ｍｍ の製品厚仕上げたのち８５０
℃で２分間の脱炭焼鈍を施し、ＭｇＯ を主成分とする
焼鈍分離剤を塗布してから８５０ ℃の２次再結晶焼鈍
引き続き１２００℃の純化焼鈍から成る最終仕上焼鈍を
行った。かくして得られた製品の磁気特性について調べ
た結果を表８に示すように、この発明の適用により、良
好な磁気特性が得られた。
【００２７】
【００２８】
【００２９】
【発明の効果】この発明によれば、特に製品厚みが０．
１０〜０．２５ｍｍの方向性けい素薄鋼板に生じやすい
、２次再結晶が未発達の異常組織を無くし、例えばコイ
ル全長にわたってばらつきのない安定した磁気特性を付
与することができる。Detailed Description of the Invention [0001] [Industrial Application Field] This invention relates to grain-oriented silicon steel sheets mainly used as core materials for transformers and other electrical equipment, particularly those having a thickness of 0.10 to This invention relates to a method for stabilizing the magnetic properties of a grain-oriented silicon steel sheet as thin as 0.25 mm. [Prior Art] Iron core materials for this type of electrical equipment must have excellent magnetic properties, specifically magnetic field strength of 800 A.
The magnetic flux density B8 (T) at /m is high and 50H
Iron loss characteristic W17/ at AC magnetic flux density 1.7 T of z
50 (W/kg) is required. For this reason, grain-oriented silicon steel sheets utilize secondary recrystallization to improve {110}
It has developed crystal grains with <001> orientation, the so-called Goss orientation. In order to obtain materials with excellent magnetic properties,
It is necessary to highly align the <001> axis, which is the axis of easy magnetization, in the rolling direction, and it is possible to stably develop secondary recrystallized grains in the Goss orientation through various processes that combine appropriate rolling and heat treatment. is important. In particular, it is already known that it is essential to uniformly and finely disperse precipitates such as MnS, MnSe, AlN, etc. called inhibitors, and to have a texture favorable to the above-mentioned secondary recrystallization. On the other hand, the product thickness is 0.10, which is advantageous for reducing iron loss.
The demand for ~0.25 mm grain-oriented silicon steel sheets is increasing, but as the sheet thickness becomes thinner, it becomes difficult to achieve stable secondary recrystallization, which causes variations in the magnetic properties of the product. This left problems with stabilization. [0004] Regarding stabilization of magnetic properties, methods include performing high-temperature treatment at the initial stage of secondary recrystallization annealing, followed by normal annealing (see Japanese Patent Publication No. 58-55212), and oxidation generated during decarburization annealing. Method of controlling quantity (Unexamined Japanese Patent Publication No. 1983
For materials containing AlN as an inhibitor, 0.0070 to 0.030% decarburization is performed in the step before decarburization annealing (see JP-A-61-117215). or Sn or Cu
A method of adding (see JP-A-2-209427) and the like have been proposed. [0005]However, although these methods improve the magnetic properties, it is difficult to provide constant magnetic properties over the entire length of the coil. In particular, it is more difficult to properly develop secondary recrystallized grains over the entire length of the coil during final finish annealing as the plate thickness becomes thinner. This is because as the plate thickness becomes thinner, the number of {110}<001> oriented grains that can become nuclei of secondary recrystallized grains decreases. Although the reason for this is not clear, it is thought that the shear strain distribution during cold rolling differs depending on the plate thickness. By the way, in Japanese Patent Application Laid-Open No. 61-238916, CBS (Contact BendStretch) is used as a texture improvement method.
tch: Special Different Circumferential Speed Rolling Method) Although a rolling method is disclosed, such a method has poor productivity and lacks feasibility. Therefore, an object of the present invention is to propose a method for manufacturing a grain-oriented silicon steel sheet having stable magnetic properties. [0006] This invention provides C: 0.02 to 0.10wt.
% (hereinafter simply shown as %), Si: 2.5 to 4.0%
and Mn: 0.03 to 0.15%, and further contains Se and/or S by 0.01 to 0.04%. In manufacturing a grain-oriented silicon steel sheet through a series of steps in which a hot-rolled sheet is cold-rolled two or more times with intermediate annealing in between, followed by decarburization annealing and final finish annealing, prior to the cold rolling, After rolling down the hot-rolled plate with a rolling mill with (roll diameter)/(plate thickness)≧50 at a rolling reduction rate of 0.5 to 15%, 700
This is a method for producing a thin grain-oriented silicon steel sheet with stable magnetic properties, which is characterized by subjecting the hot-rolled sheet to annealing in a temperature range of ~1100°C. [0007] The experimental results that formed the basis of this invention will be explained in detail below. In the process of manufacturing grain-oriented silicon steel sheets with a thickness of 0.10 to 0.25 mm, the inventors performed two cold rollings with intermediate annealing in between, and the final cold rolling reduction rate was 65%.
First, an experiment was conducted to try to optimize the rolling reduction ratio in the primary cold rolling before intermediate annealing. Experiment: C: 0.045
%, Si: 3.35%, Mn: 0.080%, S: 0
．． 025%, plate thickness 1.8 including Sb: 0.027%
The starting material was a hot-rolled sheet of mm2. Hot-rolled sheets are subjected to preliminary cold rolling (hereinafter referred to as pre-rolling) at various rolling reduction ratios to variously change the sheet thickness, and then each sheet is rolled at 1000°C for 30°C.
A material subjected to homogenization annealing of s was used. All these materials with different thicknesses are cold rolled to 0.4mm.
Finished to a thickness of 0.14 after intermediate annealing at 950°C for 60s.
After cold rolling to a thickness of mm, decarburization annealing was performed at 850° C. for 2 minutes, and after applying a separation agent containing MgO as a main component, final annealing was performed. Table 1 shows the results of investigating the magnetic properties of the obtained product. [0009] The experimental results shown in the same table show that secondary recrystallization developed stably when the reduction ratio of the first cold rolling before intermediate annealing was 75 to 76.5%, and the plate thickness was further increased. A follow-up experiment was conducted using a hot-rolled sheet finished to a thickness of 1.7 mm and not pre-rolled as a starting material under the conditions shown in Table B, but good magnetic properties could not be obtained due to the occurrence of an abnormal structure. Therefore 1
There was no correlation between the subsequent cold rolling reduction and the incidence of abnormal structures, and it was inferred that the improvement in magnetic properties was due to other factors. [0010] Therefore, the inventors conducted further experiments in order to investigate the influence of preliminary cold rolling before hot-rolled sheet annealing. That is, the starting materials used were the above-mentioned hot-rolled sheet with a thickness of 1.7 mm and hot-rolled sheets that were pre-rolled to a thickness of 1.5 mm and 1.3 mm before annealing the hot-rolled sheet. After that, the results of measuring the magnetic properties of the products obtained by hot-rolled plate annealing, primary cold rolling, intermediate annealing, secondary cold rolling, decarburization annealing, and final finish annealing under the same conditions as Table 1 are shown. Shown in 2. [0012] From the results shown in Tables 1 and 2, the inventors diligently investigated the effects caused by pre-rolling before annealing hot rolled sheets, and found that homogenization annealing at 1000°C for 30 seconds after pre-rolling was performed. It was found that there was a large difference in the crystal structure between the sample subjected to the treatment and the sample not treated. [0013] Normally, the structure of hot rolled silicon steel sheets consists of a band-like unrecrystallized structure extending in the hot rolling direction. In samples A and F that were not pre-rolled, this band-like structure remained as it was even after hot-rolled sheet annealing. In addition, in pre-rolled samples D, E, and H, the entire plate thickness was made up of recrystallized grains, although there were band-like remnants. However, in samples B, C, and G, which had a small pre-rolling reduction, recrystallized grains formed from the surface to about 1/4 of the plate thickness, and the center layer had a layered structure called a band structure. Although the reason for this is not clear, it has been found that samples with such recrystallized and band-like structures have stable magnetic properties even if they are thin plate products. Furthermore, when we repeated reproduction experiments to determine the applicable range of preliminary rolling, it was newly discovered that the effect may not be obtained depending on the rolling mill used. Since these rolling mills have different roll diameters, we conducted an experiment in which the same rolling mill was used with different work roll diameters. The material is
The hot-rolled plate is 2.0 mm thick, and the roll diameters used for preliminary rolling are 80 mmφ, 150 mmφ, 300 mmφ, and 5 mm.
00 mmφ, and the pre-rolling reduction rate was 0.5.
%, 1%, 5%, 10%, 15%, 20%, 25%, and then hot-rolled plate annealing at 1000°C for 30 seconds, the finished thickness of the first cold rolling 0.4mm
Aligned to. After that, it was intermediately annealed at 950°C for 60s to give a final thickness of 0.14mm, and further annealed at 850°C x 2
Figure 1 and Table 3 show the results of investigating the magnetic flux density and abnormal structure occurrence rate of products obtained by decarburizing annealing for 1 minute, applying an annealing separator mainly composed of MgO, and final annealing. . [0015] From the results in the same table, it can be seen that when the rolling reduction ratio is 0.5 to 15
It has been found that the occurrence of abnormal structures can be avoided by performing preliminary rolling in the range of 1.5%. It is also believed that the roll diameter also affects the recrystallization behavior, that is, the stress state exerted on the plate changes depending on the size of the roll diameter, resulting in a difference in the recrystallization behavior of the plate surface layer. This is clear from other experimental results, and the ratio of roll diameter to hot rolled sheet thickness is 50.
It has also been found that good results can be obtained when the amount is more than twice as large. [Operation] The composition of the steel slab that is the starting material of this invention is C: 0.02 to 0.10%, Si: 2.5 to 4.0%.
%, Mn: 0.03-0.15%, Se and/or S:
0.01-0.04% is required. The reason for limiting the content of each component will be explained below. C: 0.
02 to 0.10% C is required to be 0.02% or more in order to utilize γ transformation during hot rolling, but if it exceeds 0.10%, decarburization annealing in the subsequent process becomes difficult. Si: 2.5 to 4.0% If Si is less than 2.5%, the electrical resistance is low and no improvement in iron loss characteristics can be expected, while if it exceeds 4.0%, cold rolling becomes extremely difficult. . Mn: 0.03-0.15%, Se and/or S: 0.
01-0.04% Mn and Se and S are MnSe, M
It is an element necessary to form nS, and the appropriate amount of Mn is 0.03 to 0.15%, and Se and/or S is 0.01%.
%, the amount of MnSe and MnS is insufficient, and 0.
．． If it exceeds 0.05%, it becomes difficult to disperse and precipitate to a uniform fine size. [0018] In addition to the above components, Sb, Cu,
There is no problem in containing one or a combination of known elements such as Sn, Cr, Ni, and Mo. The maximum allowable amount of these elements is 0.3 for Cu, Sn, Cr, and Ni.
%, Sb, and Mo are 0.05%. That is, Cu
, Sn, Cr, Ni, etc., if the content exceeds 0.3%, not only the magnetic properties deteriorate, but also pickling properties and decarburization properties are deteriorated, which is not preferable. Furthermore, if Sb or Mo exceeds 0.05%, decarburization is significantly inhibited, which is not preferable. [0019] The molten steel having the above-mentioned composition is formed into a slab through a steelmaking and casting process according to conventional methods, subjected to solution treatment for the inhibitor component at a high temperature of 1350°C or higher, and then hot-rolled into a hot-rolled plate. . Next, after hot-rolled sheet annealing, cold rolling is performed two or more times with intermediate annealing in between, and the appropriate rolling reduction ratio for each is 30 to 80%. Prior to annealing the hot-rolled sheet, a rolling mill in which the ratio of the work roll diameter (mm) of the rolling mill to the thickness (mm) of the hot-rolled sheet is 50 times or more is used to reduce the total rolling reduction to 0.5.
Applying ~15% rolling in one or multiple passes,
It is important that the hot-rolled sheet is then annealed for a short time at 700 to 1100°C to control the crystal structure in the thickness direction before cold rolling. Hot-rolled sheet annealing must be performed at a temperature of 700°C or higher in order to recrystallize the surface layer of the pre-rolled hot-rolled sheet.On the other hand, if the temperature exceeds 1100°C, MnSe, MnS
This is not preferable because the precipitates such as the like will grow coarsely and the inhibitor function will be impaired. Regarding the time, since the purpose is recrystallization, it is sufficient to reach the desired temperature, and there is no problem even if the time is short as long as the annealing can be performed stably. [Example] Example 1 Molten steel having the composition shown in Table 4 was made into a slab by continuous casting, and after high temperature reheating at 1430°C for 15 minutes, the plate thickness was 2.7 mm.
It was made into a hot rolled sheet. This hot rolled sheet has a work roll diameter of 900.
Rolling was performed by a total of 8% in two passes using a mmφ skin pass mill. In addition, for comparison, a Sendzimer mill with a work roll diameter of 85 mmφ was used for another coil of the same composition.
Rolling was performed by 8% in total in passes. Then 1 at 1000℃
After hot-rolled plate annealing and pickling for 5 seconds, the first cold rolling was performed to obtain a plate thickness of 0.78 mm. Furthermore, as intermediate annealing, light decarburization is performed when the temperature is raised to 1000
After soaking at ℃ for 60 seconds, the mixture was rapidly cooled to room temperature. After that, it was finished with a second cold rolling to a final plate thickness of 0.30 mm, and then subjected to decarburization annealing at 850 °C for 3 minutes in a wet hydrogen atmosphere, and then an annealing separator mainly composed of MgO was applied. Secondary recrystallization annealing and final annealing were performed. As shown in Table 5, the results of investigating the magnetic properties of the thus obtained product showed that good magnetic properties were obtained by applying the present invention. [0022] [0024] Example 2 C: 0.04%, Si: 3.35%, Mn: 0.07%
, Se: 0.021%, Sb: 0.027%, Cu
: A steel slab with a composition containing 0.06% was heated at 1430℃ for 20
After heating for 30 minutes, the coil was hot-rolled to a thickness of 1.8 mm and the hot-rolled sheet of the same composition was rolled into a work roll with a diameter of 850 m.
mφ skin pass rolling mill, work roll diameter 350 mm
Coils were prepared which were pre-rolled by a total of 10% using a tandem rolling mill with a diameter of φ and a Sendzimer rolling mill with a work roll diameter of 90 mm. Thereafter, the hot-rolled plate was annealed at 900°C for 100 seconds, and finished to a thickness of 0.5 mm by cold rolling. Next, it was subjected to intermediate annealing at 950 °C for 60 seconds, then rapidly cooled to room temperature, and then cold rolled for the second time to a thickness of 0.20 mm.
Finished thickly. After further decarburizing annealing at 850° C. for 2 minutes, an annealing separator containing MgO as a main component was applied, followed by secondary recrystallization annealing and final annealing. As shown in Table 6, the magnetic properties of the thus obtained product were investigated, and as shown in Table 6, good magnetic properties were obtained by applying the present invention. Example 3 The molten steel shown in Table 7 was made into a slab by continuous casting.
After high temperature reheating at ℃ for 20 minutes, the plate thickness was 1.8 mm and 1.4 mm.
It was made into a hot rolled sheet of mm. This hot-rolled plate has a work roll diameter of 6
Rolling was performed at a rolling reduction of 5% in one pass using a skin pass mill with a diameter of 0.00 mm. For comparison, another coil having the same composition was rolled at a reduction rate of 5% in one pass using a Sendzimer mill with a work roll diameter of 80 mm. then 100
After annealing the hot-rolled sheet for 30 seconds at 0°C, pickling was carried out, and then the first cold rolling was performed using a hot-rolled sheet with a thickness of 1.8 mm as a starting material (A) 0.6 mm thick. and (B) 0.
(C) A product using a 1.4 mm thick hot-rolled plate as a starting material was finished to a thickness of 0.3 mm. Subsequently, after intermediate annealing at 950 °C x 60 s, a second cold rolling was performed to (A) 0.23 mm, (B) 0.15 mm, (
C) After finishing the product thickness of 0.10 mm, 850
Decarburization annealing was performed at 1200° C. for 2 minutes, and an annealing separator containing MgO 2 as a main component was applied, followed by final finish annealing consisting of secondary recrystallization annealing at 850° C. followed by purification annealing at 1200° C. As shown in Table 8, the results of investigating the magnetic properties of the thus obtained product showed that good magnetic properties were obtained by applying the present invention. [0027] [0028] [0029] According to the present invention, in particular, the product thickness is 0.
It is possible to eliminate the abnormal structure due to undeveloped secondary recrystallization that tends to occur in grain-oriented silicon thin steel sheets of 10 to 0.25 mm, and for example, it is possible to impart stable magnetic properties without variations over the entire length of the coil.
【図１】磁束密度におけるロール径の影響を示すグラフ
である。FIG. 1 is a graph showing the influence of roll diameter on magnetic flux density.
Claims (1)
：２．５ 〜４．０ ｗｔ％及びＭｎ：０．０３〜０．
１５ｗｔ％を含み、さらにＳｅ及び／又はＳを０．０１
〜０．０４ｗｔ％含有する組成になる鋼スラブを熱間圧
延して熱延板とした後、この熱延板に中間焼鈍を挟む２
回以上の冷間圧延を施したのち、脱炭焼鈍ついで最終仕
上げ焼鈍を施す一連の工程によって方向性けい素鋼板を
製造するに当たり、該冷間圧延に先立ち、熱延板を（ロ
ール径）／（板厚）≧５０の圧延機によって圧下率：０
．５ 〜１５％で圧下した後、７００〜１１００℃の温
度域での熱延板焼鈍を施すことを特徴とする磁気特性の
安定した薄手方向性けい素鋼板の製造方法。[Claim 1] C: 0.02 to 0.10 wt%, Si
:2.5-4.0 wt% and Mn:0.03-0.
Contains 15 wt% and further contains 0.01 Se and/or S.
After hot rolling a steel slab with a composition containing ~0.04 wt% to make a hot rolled sheet, this hot rolled sheet is subjected to intermediate annealing.
In manufacturing grain-oriented silicon steel sheets through a series of steps of cold rolling several times, followed by decarburization annealing and final finish annealing, the hot rolled sheets (roll diameter)/ (Plate thickness) ≧ 50 rolling mill Reduction rate: 0
．． 1. A method for producing a thin grain-oriented silicon steel sheet with stable magnetic properties, which comprises rolling the steel sheet by 5 to 15% and then annealing the hot-rolled sheet in a temperature range of 700 to 1100°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3074365A JPH04289121A (en) | 1991-03-15 | 1991-03-15 | Production of thin grain-oriented silicon steel sheet having stable magnetic property |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3074365A JPH04289121A (en) | 1991-03-15 | 1991-03-15 | Production of thin grain-oriented silicon steel sheet having stable magnetic property |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04289121A true JPH04289121A (en) | 1992-10-14 |
Family
ID=13545060
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3074365A Pending JPH04289121A (en) | 1991-03-15 | 1991-03-15 | Production of thin grain-oriented silicon steel sheet having stable magnetic property |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04289121A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998046802A1 (en) * | 1997-04-16 | 1998-10-22 | Acciai Speciali Terni S.P.A. | New process for the production of grain oriented electrical steel from thin slabs |
| WO2008133337A1 (en) | 2007-04-24 | 2008-11-06 | Nippon Steel Corporation | Process for producing unidirectionally grain oriented electromagnetic steel sheet |
-
1991
- 1991-03-15 JP JP3074365A patent/JPH04289121A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998046802A1 (en) * | 1997-04-16 | 1998-10-22 | Acciai Speciali Terni S.P.A. | New process for the production of grain oriented electrical steel from thin slabs |
| WO2008133337A1 (en) | 2007-04-24 | 2008-11-06 | Nippon Steel Corporation | Process for producing unidirectionally grain oriented electromagnetic steel sheet |
| US8236110B2 (en) | 2007-04-24 | 2012-08-07 | Nippon Steel Corporation | Method of producing grain-oriented electrical steel sheet |
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