JPH05156361A - Manufacture of grain-oriented electric steel sheet excellent in magnetic property - Google Patents
Manufacture of grain-oriented electric steel sheet excellent in magnetic propertyInfo
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- JPH05156361A JPH05156361A JP3281071A JP28107191A JPH05156361A JP H05156361 A JPH05156361 A JP H05156361A JP 3281071 A JP3281071 A JP 3281071A JP 28107191 A JP28107191 A JP 28107191A JP H05156361 A JPH05156361 A JP H05156361A
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、トランス等の鉄心とし
て使用される磁気特性の優れた一方向性電磁鋼板の製造
方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a grain-oriented electrical steel sheet having excellent magnetic properties, which is used as an iron core of a transformer or the like.
【０００２】[0002]
【従来の技術】一方向性電磁鋼板は、主にトランスその
他の電気機器の鉄心材料として使用されており、励磁特
性、鉄損特性等の磁気特性に優れていることが要求され
る。励磁特性を表す数値としては、通常磁場の強さ８０
０Ａ／ｍにおける磁束密度Ｂ8 が通常使用される。ま
た、鉄損特性を表す数値としては、周波数５０Hzで１．
７テスラー（Ｔ）まで磁化した時の１kg当りの鉄損Ｗ
17/50 を使用している。磁束密度は、鉄損特性の最大支
配因子であり、一般的にいって磁束密度が高いほど鉄損
特性が良好になる。なお、一般的に磁束密度を高くする
と二次再結晶粒が大きくなり、鉄損特性が不良となる場
合がある。これに対しては、磁区制御により、二次再結
晶粒の粒径に拘らず、鉄損特性の改善することができ
る。2. Description of the Related Art Unidirectional electrical steel sheets are mainly used as iron core materials for transformers and other electrical equipment, and are required to have excellent magnetic characteristics such as excitation characteristics and iron loss characteristics. As a numerical value showing the excitation characteristic, the strength of a normal magnetic field is 80
A magnetic flux density B 8 at 0 A / m is normally used. In addition, as a numerical value showing the iron loss characteristic, at a frequency of 50 Hz, 1.
Iron loss W per 1kg when magnetized to 7 Tesler (T)
I am using 17/50 . The magnetic flux density is the most dominant factor of the iron loss characteristics, and generally speaking, the higher the magnetic flux density, the better the iron loss characteristics. Generally, when the magnetic flux density is increased, the secondary recrystallized grains become large, which may result in poor iron loss characteristics. On the other hand, by controlling the magnetic domain, the iron loss characteristics can be improved regardless of the grain size of the secondary recrystallized grains.
【０００３】この一方向性電磁鋼板は、最終仕上焼鈍工
程で二次再結晶を起こさせ、鋼板面に｛１１０｝、圧延
方向に＜００１＞軸を持ったいわゆるゴス組織を発達さ
せることにより製造されている。良好な磁気特性を得る
ためには、磁化容易軸である＜００１＞を圧延方向に高
度に揃えることが必要である。This unidirectional electrical steel sheet is manufactured by causing secondary recrystallization in the final finishing annealing step to develop a so-called Goss structure having {110} axis on the steel sheet surface and <001> axis in the rolling direction. Has been done. In order to obtain good magnetic properties, it is necessary to highly align <001>, which is the easy magnetization axis, in the rolling direction.
【０００４】このような高磁束密度一方向性電磁鋼板の
製造技術として代表的なものに田口悟等による特公昭４
０−１５６４４号公報及び今中拓一等による特公昭５１
−１３４６９号公報記載の方法がある。前者においては
主なインヒビターとしてＭｎＳ及びＡｌＮを、後者では
ＭｎＳ、ＭｎＳｅ、Ｓｂ等を用いている。従って現在の
技術においてはこれらインヒビターとして機能する析出
物の大きさ、形態及び分散状態を適性制御することが不
可欠である。ＭｎＳに関して言えば、現在の工程では熱
延前のスラブ加熱時にＭｎＳを一旦完全固溶させた後、
熱延時に析出させる方法がとられている。二次再結晶に
必要な量のＭｎＳを完全固溶するためには１４００℃程
度の温度が必要である。これは普通鋼のスラブ加熱温度
に比べて２００℃以上も高く、この高温スラブ加熱処理
には以下に述べるような不利な点がある。 １）方向性電磁鋼専用の高温スラブ加熱炉が必要。 ２）加熱炉のエネルギー原単位が高い。 ３）溶融スケール量が増大し、いわゆるノロかき出し等
に見られるように操業上の悪影響が大きい。A representative technique for producing such a high magnetic flux density grain-oriented electrical steel sheet is Satoshi Taguchi et al.
0-15644 and Japanese Patent Publication Sho 51
There is a method described in JP-A-13469. In the former, MnS and AlN are used as main inhibitors, and in the latter, MnS, MnSe, Sb, etc. are used. Therefore, in the present technology, it is essential to appropriately control the size, morphology and dispersion state of the precipitates that function as these inhibitors. Speaking of MnS, in the present process, after MnS is completely solid-soluted at the time of heating the slab before hot rolling,
A method of precipitating during hot rolling is adopted. A temperature of about 1400 ° C. is necessary to completely form a solid solution of the required amount of MnS for secondary recrystallization. This is higher than the slab heating temperature of ordinary steel by 200 ° C. or more, and this high temperature slab heating treatment has the following disadvantages. 1) A high temperature slab heating furnace exclusively for grain oriented electrical steel is required. 2) The energy intensity of the heating furnace is high. 3) The amount of molten scale increases, and the adverse effect on operation is large, as seen in so-called shaving.
【０００５】このような問題点を回避するためには、ス
ラブ加熱温度を普通鋼並みに下げれば良いわけである
が、このことは同時にインヒビターとして有効なＭｎＳ
の量を少なくするかあるいは全く用いないことを意味
し、必然的に二次再結晶の不安定化をもたらす。このた
め低温スラブ加熱化を実現するためには何らかの形でＭ
ｎＳ以外の析出物などによりインヒビターを強化し、仕
上焼鈍時の正常粒成長の抑制を充分にする必要がある。
このようなインヒビターとしては硫化物の他、窒化物、
酸化物及び粒界析出元素等が考えられ、公知の技術とし
て例えば次のようなものがあげられる。In order to avoid such problems, the slab heating temperature should be lowered to the level of ordinary steel, but this is also effective as an inhibitor of MnS.
Is meant to be used in a small amount or not used at all, which necessarily causes destabilization of secondary recrystallization. Therefore, in order to realize low-temperature slab heating, M
It is necessary to strengthen the inhibitor with precipitates other than nS to sufficiently suppress normal grain growth during finish annealing.
Such inhibitors include sulfides, nitrides,
Oxides, grain boundary precipitation elements and the like are considered, and known techniques include, for example, the following.
【０００６】特公昭５４−２４６８５号公報ではＡｓ、
Ｂｉ、Ｓｎ、Ｓｂ等の粒界偏析元素を鋼中に含有するこ
とにより、スラブ加熱温度を１０５０〜１３５０℃の範
囲にする方法が開示され、特開昭５２−２４１１６号公
報ではＡｌの他、Ｚｒ、Ｔｉ、Ｂ、Ｎｂ、Ｔａ、Ｖ、Ｃ
ｒ、Ｍｏ等の窒化物生成元素を含有することによりスラ
ブ加熱温度を１１００〜１２６０℃の範囲にする方法が
開示されている。また、特開昭５７−１５８３２２号公
報にはＭｎ含有量を下げ、Ｍｎ／Ｓの比率を２．５以下
にすることにより低温スラブ加熱化を行い、さらにＣｕ
の添加により二次再結晶を安定化する技術を開示してい
る。一方、これらインヒビターの補強と組み合わせて金
属組織の側から改良を加えた技術も開示された。すなわ
ち特開昭５７−８９４３３号公報ではＭｎに加えＳ、Ｓ
ｅ、Ｓｂ、Ｂｉ、Ｐｂ、Ｓｎ、Ｂ等の元素を加え、これ
にスラブの柱状晶率と二次冷延圧下率を組み合わせるこ
とにより１１００〜１２５０℃の低温スラブ加熱化を実
現している。さらに特開昭５９−１９０３２４号公報で
はＳあるいはＳｅに加え、Ａｌ及びＢと窒素を主体とし
てインヒビターを構成し、これに冷延後の一次再結晶焼
鈍時にパルス焼鈍を施すことにより二次再結晶を安定化
する技術を提示している。このように方向性電磁鋼板製
造における低温スラブ加熱化実現のためには、これまで
に多大な努力が続けられてきている。In Japanese Patent Publication No. 54-24685, As,
A method of controlling the slab heating temperature in the range of 1050 to 1350 ° C. by containing grain boundary segregation elements such as Bi, Sn, and Sb in the steel is disclosed, and in JP-A-52-24116, in addition to Al, Zr, Ti, B, Nb, Ta, V, C
There is disclosed a method in which the slab heating temperature is set to a range of 1100 to 1260 ° C. by containing a nitride-forming element such as r or Mo. Further, in JP-A-57-158322, low temperature slab heating is performed by reducing the Mn content and setting the Mn / S ratio to 2.5 or less.
Discloses a technique for stabilizing the secondary recrystallization by adding. On the other hand, a technique was also disclosed in which improvement was made from the side of the metal structure in combination with reinforcement of these inhibitors. That is, in JP-A-57-89433, S, S
Elements such as e, Sb, Bi, Pb, Sn, and B are added, and the columnar crystal ratio of the slab and the secondary cold rolling reduction are combined to achieve low temperature slab heating at 1100 to 1250 ° C. Further, in JP-A-59-190324, an inhibitor is mainly composed of Al and B and nitrogen in addition to S or Se, and secondary annealing is performed by performing pulse annealing during primary recrystallization annealing after cold rolling. The technology that stabilizes is presented. Thus, in order to realize low temperature slab heating in the production of grain-oriented electrical steel sheets, great efforts have been made so far.
【０００７】さて、特開昭５９−５６５２２号公報にお
いては、Ｍｎを０．０８〜０．４５％、Ｓを０．００７
％以下にすることにより低温スラブ加熱化を可能にする
技術が開示された。この方法により高温スラブ加熱時の
スラブ結晶粒粗大化に起因する製品の線状二次再結晶不
良発生の問題が解消された。Now, in JP-A-59-56522, Mn is 0.08 to 0.45% and S is 0.007.
A technique has been disclosed that enables low temperature slab heating by controlling the content to be not more than%. By this method, the problem of defective linear secondary recrystallization of the product due to coarsening of the slab crystal grains during heating of the high temperature slab was solved.
【０００８】[0008]
【発明が解決しようとする課題】低温スラブ加熱化が可
能となったこと自体は上記の如く工業的には大きなメリ
ットがあるが、生産管理等に余分の労力をさくことは、
コストダウンの点で好ましくない。そこで、低温スラブ
加熱を前提として、生産管理等の労力を少なくし、かつ
磁気特性を高位安定化させる工程設計が必要となる。こ
のためには、工程数を増すことも総合的には許容される
場合もある。本発明は、このような要求を充足し、かつ
優れた磁気特性を有する一方向性電磁鋼板の製造方法を
提供するものである。The fact that low-temperature slab heating is possible has a great industrial advantage as described above, but it is not necessary to put extra effort into production control.
It is not preferable in terms of cost reduction. Therefore, on the premise of low-temperature slab heating, it is necessary to reduce the labor such as production control and design the process to stabilize the magnetic characteristics at a high level. For this purpose, it may be totally acceptable to increase the number of steps. The present invention provides a method for manufacturing a grain-oriented electrical steel sheet which satisfies such requirements and has excellent magnetic properties.
【０００９】[0009]
【課題を解決するための手段】本発明の要旨とするとこ
ろは下記の通りである。すなわち、 (1) 重量％で Ｃ：０．０２５〜０．０７５％、Ｓｉ：２．５〜４．５
％、酸可溶性Ａｌ：０．０１０〜０．０６０％、Ｎ：
０．００１０〜０．０１３０％、Ｓ＋０．４０５Ｓｅ：
０．０１４％以下、Ｍｎ：０．０５〜０．８％を含有
し、残部がＦｅ及び不可避的不純物からなるスラブを１
２８０℃未満の温度で加熱した後、熱延し、得られた熱
延板を圧下率６０〜７９％の最終冷延を含み、必要に応
じて中間焼鈍をはさむ２回以上の冷延を行い、次いで脱
炭焼鈍、最終仕上焼鈍を施して一方向性電磁鋼板を製造
する方法において、脱炭焼鈍完了後、最終仕上焼鈍開始
までの一次再結晶粒の平均粒径を１０〜３５μｍとし、
熱延後、最終仕上焼鈍の二次再結晶開始までの間に鋼板
に窒化処理を施すことを特徴とする磁気特性の優れた一
方向性電磁鋼板の製造方法。The gist of the present invention is as follows. That is, (1) C: 0.025 to 0.075% by weight%, Si: 2.5 to 4.5
%, Acid-soluble Al: 0.010 to 0.060%, N:
0.0010 to 0.0130%, S + 0.405Se:
A slab containing 0.014% or less, Mn: 0.05 to 0.8%, and the balance being Fe and inevitable impurities is 1
After heating at a temperature of less than 280 ° C., hot rolling is performed, and the obtained hot rolled sheet includes final cold rolling with a rolling reduction of 60 to 79%, and if necessary, is subjected to two or more cold rollings with intermediate annealing. , Then, decarburization annealing, in the method of producing a final finishing annealing to produce a grain-oriented electrical steel sheet, after decarburization annealing is completed, the average particle size of the primary recrystallized grains until the start of final finishing annealing is 10 to 35 μm,
A method for producing a grain-oriented electrical steel sheet having excellent magnetic properties, which comprises subjecting a steel sheet to a nitriding treatment after hot rolling and before the start of secondary recrystallization of final finish annealing.
【００１０】(2) 前項の最終仕上焼鈍での二次再結晶開
始直前の鋼板には重量％でＮ：０．０１００％以上が含
有されることを特徴とする磁気特性の優れた一方向性電
磁鋼板の製造方法である。(2) The steel sheet immediately before the start of secondary recrystallization in the final finish annealing described in the preceding paragraph contains N: 0.0100% or more by weight%, which is an excellent unidirectional property of magnetic properties. It is a method of manufacturing an electromagnetic steel sheet.
【００１１】[0011]
【作用】本発明が対象としている一方向性電磁鋼板は、
従来用いられている製鋼法で得られた溶鋼を連続鋳造法
あるいは造塊法で鋳造し、必要に応じて分塊工程をはさ
んでスラブとし、引き続き熱間圧延して熱延板とし、次
いで必要に応じて熱延板焼鈍を施し、この熱延板に圧下
率６０〜７９％の最終冷延を含み、中間焼鈍をはさむ２
回以上の冷延を行い、次いで脱炭焼鈍、最終仕上焼鈍を
順次行うことによって製造される。The function of the grain-oriented electrical steel sheet of the present invention is
The molten steel obtained by the conventional steelmaking method is cast by a continuous casting method or an ingot making method, and if necessary, the slab is separated by a slab, and then hot-rolled into a hot-rolled sheet. If necessary, hot-rolled sheet annealing is performed, and this hot-rolled sheet includes final cold rolling with a rolling reduction of 60 to 79%, and intermediate annealing is performed 2.
It is manufactured by performing cold rolling more than once and then sequentially performing decarburization annealing and final finishing annealing.
【００１２】本発明の特徴である脱炭焼鈍完了後、最終
仕上焼鈍開始までの間での一次再結晶粒径制御の効果に
ついて、実験結果を基に説明する。図１は一次再結晶粒
径が製品の磁束密度に与える影響をあらわしたグラフで
ある。ここでの実験は、重量％で、Ｃ＝０．０５３％、
Ｓｉ＝３．２５％、酸可溶性Ａｌ＝０．０１５〜０．０
４３％、Ｎ＝０．００３３〜０．００９５％、Ｓ＝０．
００７％、Ｍｎ＝０．１４％を含有し、残部Ｆｅ及び不
可避的不純物からなる４０mm厚のスラブを１１５０℃に
加熱し、６パスで２．３mm厚の熱延板とした。この熱延
板を酸洗し、次いで圧下率約４２％で冷延し、１．３４
mm厚とした。しかる後この鋼板に１１００℃×３０秒均
熱し、９００℃まで徐冷後急冷する中間焼鈍を施し、次
いで、圧下率７５％で冷延し、０．３３５mm厚の冷延板
とした。その後、この冷延板を７８０〜１０００℃に１
５０秒保持する脱炭焼鈍を施した。この時の焼鈍雰囲気
はＮ2 ２５％とＨ2 ７５％の混合ガスで露点は６２℃で
あった。しかる後、７５０℃に３０秒保持する熱処理
中、雰囲気ガス中にＮＨ3 ガスを混入させ鋼板に窒素処
理を施した。窒化後の鋼板のＮ量は０．０１７９〜０．
０２０８重量％であった。また、この鋼板の一次再結晶
粒の平均粒径（円相当直径）を光学顕微鏡と画像解析機
を用いて測定した。次いで、窒化後の鋼板にＭｇＯを主
成分とする焼鈍分離剤を塗布し、Ｎ2 ：２５％、Ｈ2 ：
７５％の混合ガス中で１２００℃まで１５℃／hrで昇温
し、Ｈ2 ：１００％中に１２００℃で２０時間保持する
最終仕上焼鈍を行った。The effect of controlling the primary recrystallized grain size between the completion of decarburization annealing and the start of final finish annealing, which is a feature of the present invention, will be described based on experimental results. FIG. 1 is a graph showing the effect of the primary recrystallized grain size on the magnetic flux density of the product. In this experiment, the weight% is C = 0.053%,
Si = 3.25%, acid-soluble Al = 0.015 to 0.0
43%, N = 0.333 to 0.0095%, S = 0.
A slab containing 007% and Mn = 0.14% and having a balance of Fe and unavoidable impurities and having a thickness of 40 mm was heated to 1150 ° C., and a hot rolled sheet having a thickness of 2.3 mm was formed by 6 passes. The hot-rolled sheet was pickled, then cold-rolled at a rolling reduction of about 42% to obtain 1.34.
mm thickness. Thereafter, this steel sheet was soaked at 1100 ° C. for 30 seconds, subjected to intermediate annealing by gradually cooling to 900 ° C. and then rapidly cooling, and then cold rolled at a rolling reduction of 75% to obtain a 0.335 mm thick cold rolled sheet. Then, this cold rolled sheet is heated to 780 to 1000 ° C for 1 hour.
Decarburization annealing was performed for 50 seconds. At this time, the annealing atmosphere was a mixed gas of 25% N 2 and 75% H 2 , and the dew point was 62 ° C. After that, during the heat treatment of holding at 750 ° C. for 30 seconds, NH 3 gas was mixed in the atmosphere gas to subject the steel sheet to nitrogen treatment. The N content of the steel sheet after nitriding was 0.0179 to 0.
It was 0208% by weight. The average grain size (equivalent circle diameter) of the primary recrystallized grains of this steel sheet was measured using an optical microscope and an image analyzer. Then, an annealing separator containing MgO as a main component is applied to the steel sheet after nitriding, and N 2 : 25%, H 2 :
A final finishing annealing was carried out by raising the temperature to 1200 ° C. at a rate of 15 ° C./hr in a 75% mixed gas and holding the temperature in H 2 : 100% at 1200 ° C. for 20 hours.
【００１３】図１から明らかなように一次再結晶粒の平
均粒径が１０〜３５μｍの範囲で、Ｂ8 ≧１．８５Ｔな
る良好な磁気特性が得られている。As is apparent from FIG. 1, good magnetic properties of B 8 ≧ 1.85 T are obtained when the average grain size of the primary recrystallized grains is in the range of 10 to 35 μm.
【００１４】図１に示した如き関係が成立する理由につ
いては必ずしも明らかではないが、本発明者らは次のよ
うに推察している。すなわち、二次再結晶方位に対する
一時再結晶集合組織の影響メカニズムは、対応方位とい
う概念を用いて説明できると考えられる。本発明の如き
６０〜７９％の低圧下率最終冷延の場合、一次再結晶集
合組織は、それほど尖鋭には発達しない。従って、二次
再結晶方位に対する対応方位もそれほど強くならない。
この様な場合、二次再結晶する核の存在量とそれに対す
る対応方位の量の積の多い核が二次再結晶しやすいと考
えられる。この時、上記の積の二次再結晶に必要な臨界
値が重要となり、この臨界値が高過ぎると、様々な方位
を持つ二次再結晶粒が発生することとなる。そして、一
次再結晶粒径の逆数は、二次再結晶粒の粒成長の駆動力
に比例する量と考えられるので、一次再結晶の平均粒径
が小さいほど、上臨界値が低く、大きいほど臨界値が高
いと考えれる。従って図１に示した如く、１０〜３５μ
ｍに一次再結晶の平均粒径の適性値が存在したものとい
える。１０μｍ超の場合、何れも、二次再結晶が不良と
なっており、上記臨界値の適性範囲と一次再結晶粒径の
適性範囲が対応しているものと解される。Although the reason why the relationship shown in FIG. 1 is established is not always clear, the present inventors presume as follows. That is, it is considered that the mechanism of influence of the temporary recrystallization texture on the secondary recrystallization orientation can be explained by using the concept of corresponding orientation. In the case of 60-79% low pressure final cold rolling as in the present invention, the primary recrystallization texture does not develop so sharply. Therefore, the orientation corresponding to the secondary recrystallization orientation does not become so strong.
In such a case, it is considered that the nuclei having a large product of the abundance of the secondary recrystallized nuclei and the corresponding orientation amount are likely to be secondary recrystallized. At this time, the critical value required for secondary recrystallization of the above product becomes important, and if this critical value is too high, secondary recrystallized grains having various orientations will be generated. Since the reciprocal of the primary recrystallized grain size is considered to be proportional to the driving force for grain growth of the secondary recrystallized grain, the smaller the average grain size of the primary recrystallized grains, the lower the upper critical value, the larger the It seems that the critical value is high. Therefore, as shown in FIG.
It can be said that there was an appropriate value of the average particle size of the primary recrystallization in m. In the case where it exceeds 10 μm, the secondary recrystallization is poor in all cases, and it is understood that the appropriate range of the critical value and the appropriate range of the primary recrystallized grain size correspond to each other.
【００１５】次に本発明の構成要件の限定理由について
述べる。先ず、スラブ成分とスラブ加熱温度に関して限
定理由を詳細に説明する。Ｃは０．０２５重量％（以下
単に％と略述）未満になると二次再結晶が不安定にな
り、かつ二次再結晶した場合でもＢ8 ＞１．８０（Ｔ）
が得がたいので０．０２５％以上とした。一方、Ｃが多
くなり過ぎると脱炭焼鈍時間が長くなり経済的でないの
で０．０７５％以下とした。Next, the reasons for limiting the constituent features of the present invention will be described. First, the reasons for limiting the slab components and the slab heating temperature will be described in detail. When C is less than 0.025% by weight (hereinafter simply referred to as%), the secondary recrystallization becomes unstable, and even when the secondary recrystallization is performed, B 8 > 1.80 (T)
Since it is difficult to obtain, it was set to 0.025% or more. On the other hand, if C is too much, the decarburization annealing time becomes long and it is not economical, so the content was made 0.075% or less.
【００１６】Ｓｉは４．５％を超えると冷延時の割れが
著しくなるので４．５％以下とした。また、２．５％未
満では素材の固有抵抗が低過ぎ、トランス鉄心材料とし
て必要な低鉄損が得られないので２．５％以上とした。
望ましくは３．２％以上である。If Si exceeds 4.5%, cracking during cold rolling becomes significant, so Si is set to 4.5% or less. If it is less than 2.5%, the specific resistance of the material is too low, and the low iron loss required for the transformer core material cannot be obtained.
It is preferably 3.2% or more.
【００１７】Ａｌは二次再結晶の安定化に必要なＡｌＮ
もしくは（Ａｌ，Ｓｉ）窒化物を確保するため、酸可溶
性Ａｌとして０．０１０％以上が必要である。酸可溶性
Ａｌが０．０６０％を超えると熱延板のＡｌＮが不適切
となり二次再結晶が不安定となるので０．０６０％以下
とした。Al is AlN necessary for stabilizing secondary recrystallization.
Alternatively, in order to secure (Al, Si) nitride, 0.010% or more is required as acid-soluble Al. If the acid-soluble Al exceeds 0.060%, the AlN of the hot-rolled sheet becomes unsuitable and the secondary recrystallization becomes unstable, so the content was made 0.060% or less.
【００１８】Ｎについては通常の製鋼作業では０．００
１０％未満にすることが困難であり、かつ経済的に好ま
しくないので０．００１０％以上とし、一方、０．０１
３０％を超えるとブリスターと呼ばれる“鋼板のふく
れ”が発生するので０．０１３０％以下とした。N is 0.00 in the ordinary steelmaking work.
Since it is difficult to make it less than 10% and it is not economically preferable, it is set to 0.0010% or more, while 0.01
When it exceeds 30%, "blister of steel plate" called blister occurs, so the content is made 0.0130% or less.
【００１９】ＭｎＳ、ＭｎＳｅが鋼中に存在しても、製
造工程の条件を適性に選ぶことによって磁気特性を良好
にすることは可能である。しかしながらＳやＳｅが高い
と線状細粒と呼ばれる二次再結晶不良部が発生する傾向
があり、この二次再結晶不良部の発生を予防するために
は（Ｓ＋０．４０５Ｓｅ）≦０．０１４％とすべきであ
る。ＳあるいはＳｅが上記値を超える場合には製造条件
をいかに変更しても二次再結晶不良部が発生する確率が
高くなり好ましくない。また、最終仕上焼鈍で純化する
のに要する時間が長くなり過ぎて好ましくなく、この様
な観点からＳあるいはＳｅを不必要に増すことは意味が
ない。Even if MnS and MnSe are present in the steel, it is possible to improve the magnetic properties by appropriately selecting the conditions of the manufacturing process. However, if S and Se are high, secondary recrystallization defects called linear fine grains tend to occur. To prevent the generation of secondary recrystallization defects, (S + 0.405Se) ≦ 0.014 Should be%. If S or Se exceeds the above value, the probability of occurrence of defective secondary recrystallization is increased no matter how the manufacturing conditions are changed, which is not preferable. In addition, the time required for purification in the final finish annealing is undesirably long, and it is meaningless to increase S or Se unnecessarily from this viewpoint.
【００２０】Ｍｎの下限値は０．０５％である。０．０
５％未満では、熱間圧延によって得られる熱延板の形状
（平坦さ）、ストリップの側縁部が波形状となり製品歩
留りを低下させる問題が発生する。一方、Ｍｎ量が０．
８％を超えると製品の磁束密度を低下させ、好ましくな
いので、Ｍｎ量の上限を０．８％とした。The lower limit of Mn is 0.05%. 0.0
If it is less than 5%, the shape (flatness) of the hot-rolled sheet obtained by hot rolling and the side edge portion of the strip become wavy, which causes a problem of lowering the product yield. On the other hand, the Mn content is 0.
If it exceeds 8%, the magnetic flux density of the product is lowered, which is not preferable, so the upper limit of the amount of Mn was set to 0.8%.
【００２１】この他、インヒビター構成元素としている
Ｓｎ、Ｓｂ、Ｃｒ、Ｃｕ、Ｎｉ、Ｂ、Ｔｉ等を微量に含
有することは差し支えない。In addition to this, a small amount of Sn, Sb, Cr, Cu, Ni, B, Ti, etc., which are inhibitor constituent elements, may be contained.
【００２２】スラブ加熱温度は、普通鋼並にしてコスト
ダウンを行うという目的から１２８０℃未満と限定し
た。好ましくは１２００℃以下である。スラブ加熱に引
き続き、通常の方法で熱延が行われ、熱延板となる。次
いで、圧下率６０〜７９％の最終冷延を含み、必要に応
じて中間焼鈍をはさみ２回以上の冷延を行う。最終冷延
の圧下率が６０％未満では｛１１１｝＜１１２＞等｛１
１０｝＜００１＞に対する対応方位が少なすぎて高い磁
束密度を得るには好ましくなく、７９％超では、高磁束
密度は得られるものの、適性な一次再結晶粒径の範囲が
狭くなるので良好な磁気特性を安定して得る点では不利
である。このため、最終冷延圧下率を６０〜７９％と規
定した。The slab heating temperature is limited to less than 1280 ° C. for the purpose of cost reduction in the same manner as ordinary steel. It is preferably 1200 ° C or lower. Subsequent to slab heating, hot rolling is performed by a usual method to obtain a hot rolled sheet. Then, the final cold rolling with a rolling reduction of 60 to 79% is included, and if necessary, intermediate annealing is performed, and cold rolling is performed twice or more. If the final cold rolling reduction is less than 60%, {111} <112> etc. {1
10} <001> is too small to obtain a high magnetic flux density, and if it exceeds 79%, a high magnetic flux density can be obtained, but an appropriate range of primary recrystallized grain size becomes narrow, which is preferable. It is disadvantageous in that the magnetic characteristics are stably obtained. Therefore, the final cold rolling reduction rate is defined as 60 to 79%.
【００２３】かかる冷延後の鋼板は、通常の方法で脱炭
焼鈍、焼鈍分離剤塗布、最終仕上焼鈍を施されて最終製
品となる。ここで脱炭焼鈍完了後、最終仕上焼鈍開始ま
での間の一次再結晶粒の平均粒径を１０〜３５μｍとし
たのは、図１に示した如くこの値の範囲でＢ8 （Ｔ）
１．８５なる良好な磁束密度が得られるからである。そ
して、熱延後最終仕上焼鈍の二次再結晶開始までの間に
鋼板に窒化処理を施すと規定したのは、本発明の如き低
温スラブ加熱を前提とするプロセスでは、二次再結晶に
必要なインヒビター強度が不足がちになるからである。
窒化の方法としては特に限定するものではなく、脱炭焼
鈍後引き続き焼鈍雰囲気にＮＨ3 ガスを混入させ窒化す
る方法、プラズマを用いる方法、焼鈍分離剤に窒化物を
添加し、最終仕上焼鈍の昇温中に窒化物が分解してでき
た窒素を鋼板に吸収させる方法、最終仕上焼鈍の雰囲気
のＮ2 分圧を高めとし、鋼板を窒化する方法等何れの方
法でも良い。窒化量については特に限定するものではな
いが、１ppm 以上は必要である。The steel sheet after cold rolling is subjected to decarburization annealing, application of an annealing separating agent, and final finishing annealing by a usual method to obtain a final product. The average grain size of the primary recrystallized grains after the completion of decarburization annealing and before the start of final finishing annealing is set to 10 to 35 μm as shown in FIG. 1 within the range of B 8 (T).
This is because a good magnetic flux density of 1.85 can be obtained. Then, it is defined that the steel sheet is subjected to the nitriding treatment before the start of the secondary recrystallization of the final finish annealing after the hot rolling, in the process premised on the low temperature slab heating as in the present invention, it is necessary for the secondary recrystallization. This is because the inhibitor strength tends to be insufficient.
The method of nitriding is not particularly limited, and it is a method of mixing NH 3 gas into the annealing atmosphere after decarburization annealing to perform nitriding, a method of using plasma, a nitride is added to an annealing separating agent, and a final finishing annealing is performed. Any method may be used, such as a method of absorbing nitrogen generated by decomposition of nitrides in the temperature into the steel sheet, or a method of nitriding the steel sheet by increasing the N 2 partial pressure in the atmosphere of final annealing. The nitriding amount is not particularly limited, but 1 ppm or more is necessary.
【００２４】最終仕上焼鈍においては、例えば、Ｈ2 中
で焼鈍する等の場合、鋼板から脱窒が生じやすく、たと
え、最終仕上焼鈍前に窒化処理を施したとしても、二次
再結晶を生ぜしめ、かつ良好な磁気特性を得るための析
出物が不足する場合も考える。二次再結晶開始直前の鋼
板においては、Ｎが重量で０．０１００％以上が含有さ
れていることが、良好な磁気特性を得るためにさらに好
ましい。最終仕上焼鈍条件は、特に限定するものではな
いが、Ｎ2 分圧を１％以上とした雰囲気中で焼鈍するこ
とは、二次再結晶安定化の点で好ましい。In the final finish annealing, for example, in the case of annealing in H 2 or the like, denitrification is likely to occur from the steel sheet, and even if a nitriding treatment is performed before the final finish annealing, secondary recrystallization occurs. It is also considered that there is a shortage of precipitates for tightening and obtaining good magnetic properties. In the steel sheet immediately before the start of secondary recrystallization, it is more preferable that the N content is 0.0100% or more by weight in order to obtain good magnetic properties. The final finish annealing conditions are not particularly limited, but annealing in an atmosphere with a N 2 partial pressure of 1% or more is preferable from the viewpoint of stabilizing secondary recrystallization.
【００２５】[0025]
【実施例】以下実施例を説明する。 ［実施例１］Ｃ：０．０５５重量％、Ｓｉ：３．２４重
量％、Ｍｎ：０．１５重量％、Ｓ：０．００７重量％、
酸可溶性Ａｌ：０．０２９重量％、Ｎ：０．００７６重
量％を含有し、残部Ｆｅ及び不可避的不純物からなる４
０mm厚スラブを１１５０℃の温度で６０分加熱した後、
１０８０℃で熱延を開始し、２．３mm厚の熱延板とし
た。この熱延板を酸洗し、次いで圧下率約３４％で冷却
し、１．５２mm厚とした。しかる後この鋼板を１０５０
℃×３０秒（均熱）の処理後、９００℃まで徐冷した後
急冷する中間焼鈍を施した。次いで圧下率約７８％で冷
却し、０．３３５mm厚の冷延板とした。EXAMPLES Examples will be described below. [Example 1] C: 0.055 wt%, Si: 3.24 wt%, Mn: 0.15 wt%, S: 0.007 wt%,
Acid-soluble Al: 0.029% by weight, N: 0.0076% by weight, balance Fe and unavoidable impurities 4
After heating the 0 mm thick slab at a temperature of 1150 ° C. for 60 minutes,
Hot rolling was started at 1080 ° C. to obtain a hot rolled sheet having a thickness of 2.3 mm. The hot rolled sheet was pickled and then cooled at a rolling reduction of about 34% to a thickness of 1.52 mm. After that, this steel plate is 1050
After the treatment at 30 ° C. for 30 seconds (soaking), the intermediate annealing was performed by gradually cooling to 900 ° C. and then rapidly cooling. Then, it was cooled at a rolling reduction of about 78% to obtain a cold-rolled sheet having a thickness of 0.335 mm.
【００２６】この冷延板に８３０℃×１５０秒（均熱）
なる脱炭焼鈍を施した。脱炭焼鈍後の鋼板の平均粒径
（円相当直径）は、２２μｍであった。次いでかかる鋼
板に、７５０℃に３０秒保持する熱処理中、雰囲気ガ
ス中にＮＨ3 ガスを混入させて窒化処理，処理なしの
２条件の処理を施した。条件の窒化後の鋼板のＮ量
は、０．０１８８重量％であった。その後、の鋼板
にＭｇＯを主成分とする焼鈍分離剤を塗布し、公知の方
法で最終仕上焼鈍を行った。実験条件と製品の磁気特性
の結果を表１に示す。830 ° C. × 150 seconds (soaking) on this cold rolled sheet
Decarburization annealing was applied. The average grain size (circle equivalent diameter) of the steel sheet after decarburization annealing was 22 μm. Next, during the heat treatment of holding the steel plate at 750 ° C. for 30 seconds, NH 3 gas was mixed into the atmosphere gas and subjected to the two conditions of nitriding treatment and non-treatment. The N content of the steel sheet after nitriding under the conditions was 0.0188% by weight. After that, an annealing separator having MgO as a main component was applied to the steel sheet, and final finish annealing was performed by a known method. Table 1 shows the experimental conditions and the results of the magnetic properties of the products.
【００２７】[0027]
【表１】 [Table 1]
【００２８】［実施例２］Ｃ：０．０４８重量％、Ｓ
ｉ：３．２３重量％、Ｍｎ：０．１４重量％、Ｓ：０．
００７重量％、酸可溶性Ａｌ：０．０１８重量％、Ｎ：
０．００８９重量％を含有し、残部Ｆｅ及び不可避的不
純物からなる４０mm厚スラブを１２５０℃の温度で６０
分加熱した後、直ちに熱延を行い、２．３mm厚の熱延板
とした。この熱延板を酸洗し、次いで圧下率約４２％で
冷却し、１．３４mm厚とした。しかる後この鋼板に９８
０℃×２分（均熱）後、６００℃まで空冷した後急冷す
る中間焼鈍を施し、次いで圧下率７５％で冷却し、０．
３３５mm厚の冷延板とした。[Example 2] C: 0.048% by weight, S
i: 3.23% by weight, Mn: 0.14% by weight, S: 0.
007% by weight, acid-soluble Al: 0.018% by weight, N:
A 40 mm thick slab containing 0.0089% by weight and the balance Fe and unavoidable impurities was added at a temperature of 1250 ° C. to 60
Immediately after heating for a minute, hot rolling was performed to obtain a hot rolled sheet having a thickness of 2.3 mm. The hot rolled sheet was pickled and then cooled at a rolling reduction of about 42% to have a thickness of 1.34 mm. Then 98 on this steel plate
After 0 ° C. × 2 minutes (soaking), it was air-cooled to 600 ° C. and then subjected to an intermediate annealing of rapid cooling, followed by cooling at a reduction rate of 75%,
A cold-rolled sheet having a thickness of 335 mm was used.
【００２９】その後この冷延板にａ：８００℃×１５０
秒（均熱），ｂ：８４０℃×１５０秒（均熱）なる２水
準の脱炭焼鈍を施した。この場合、一次再結晶粒の平均
粒径（円相当直径）はａ：９μｍ，ｂ：１３μｍであっ
た。かかる鋼板に実施例１記載の窒化処理、を施し
た。条件の窒化後の鋼板のＮ量は、０．０１６９〜
０．０１８１重量％であった。しかる後、ＭｇＯを主成
分とする焼鈍分離剤を塗布し、公知の方法で最終仕上焼
鈍を行った。実験条件と製品の磁気特性を表２に示す。Thereafter, a: 800 ° C. × 150 was applied to this cold rolled sheet.
Seconds (soaking), b: 840 ° C. × 150 seconds (soaking), two levels of decarburization annealing. In this case, the average grain size (equivalent circle diameter) of the primary recrystallized grains was a: 9 μm, b: 13 μm. This steel sheet was subjected to the nitriding treatment described in Example 1. The N content of the steel sheet after nitriding under the conditions is 0.0169 to
It was 0.0181% by weight. After that, an annealing separator containing MgO as a main component was applied, and final finish annealing was performed by a known method. Table 2 shows the experimental conditions and the magnetic properties of the products.
【００３０】[0030]
【表２】 [Table 2]
【００３１】［実施例３］Ｃ：０．０４０重量％、Ｓ
ｉ：３．３０重量％、Ｍｎ：０．１４重量％、Ｓ：０．
００６重量％、酸可溶性Ａｌ：０．０４８重量％、Ｎ：
０．００５１重量％を含有し、残部Ｆｅ及び不可避的不
純物からなる４０mm厚スラブを１１００℃の温度で６０
分加熱した後、直ちに熱延を行い、２．３mm厚の熱延板
とした。この熱延板に１０００℃×２分間均熱後、６０
０℃まで空冷した後急冷する熱延板焼鈍を施し、次いで
酸洗、圧下率５０％の冷延を施し、１．１５mm厚の冷延
板とした。しかる後、この冷延板に１０００℃×２分
（均熱）の処理後、９００℃まで徐冷した後急冷する中
間焼鈍を施した。次いで圧下率約７５％で冷却し、０．
２８５mm厚の冷延板とした。[Example 3] C: 0.040% by weight, S
i: 3.30% by weight, Mn: 0.14% by weight, S: 0.
006% by weight, acid-soluble Al: 0.048% by weight, N:
A 40 mm-thick slab containing 0.0051% by weight and the balance Fe and unavoidable impurities at a temperature of 1100 ° C.
Immediately after heating for a minute, hot rolling was performed to obtain a hot rolled sheet having a thickness of 2.3 mm. After soaking this hot rolled sheet for 2 minutes at 1000 ° C, 60
A hot-rolled sheet was annealed by air-cooling to 0 ° C. and then rapidly cooled, then pickled and cold-rolled at a reduction rate of 50% to obtain a 1.15 mm-thick cold-rolled sheet. Thereafter, this cold-rolled sheet was subjected to an intermediate annealing of 1000 ° C. × 2 minutes (soaking), then gradually cooled to 900 ° C. and then rapidly cooled. Then, it is cooled at a reduction rate of about 75%, and
A cold rolled sheet having a thickness of 285 mm was used.
【００３２】この冷延板にａ：８５０℃×１５０秒（均
熱），ｂ：９５０℃×１５０秒（均熱）なる２水準の脱
炭焼鈍を施した。この場合、一次再結晶粒の平均粒径
（円相当直径）はａ：２６μｍ，ｂ：３７μｍであっ
た。かかる鋼板に実施例１記載の窒化処理、を施し
た。条件の窒化後の鋼板のＮ量は、０．０１９３〜
０．０２０１重量％であった。その後、ＭｇＯを主成分
とする焼鈍分離剤を塗布し、公知の方法で最終仕上焼鈍
を行った。実験条件と製品の磁気特性を表３に示す。This cold-rolled sheet was subjected to two levels of decarburization annealing: a: 850 ° C. × 150 seconds (soaking), b: 950 ° C. × 150 seconds (soaking). In this case, the average grain size (equivalent circle diameter) of the primary recrystallized grains was a: 26 μm, b: 37 μm. This steel sheet was subjected to the nitriding treatment described in Example 1. The N content of the steel sheet after nitriding under the conditions is 0.0193 to
It was 0.0201% by weight. After that, an annealing separator containing MgO as a main component was applied, and final finish annealing was performed by a known method. Table 3 shows the experimental conditions and the magnetic properties of the products.
【００３３】[0033]
【表３】 [Table 3]
【００３４】［実施例４］Ｃ：０．０４５重量％、Ｓ
ｉ：３．２５重量％、Ｍｎ：０．１５重量％、Ｓ：０．
００７重量％、酸可溶性Ａｌ：０．０３０重量％、Ｎ：
０．００８７重量％、Ｓｎ：０．０５０重量％を含有
し、残部Ｆｅ及び不可避的不純物からなる４０mm厚スラ
ブを１１５０℃の温度で６０分加熱した後、直ちに熱延
を行い、２．３mm厚の熱延板とした。この熱延板を酸洗
し、次いで圧下率約３４％で冷延し、１．５２mm厚とし
た。しかる後、この鋼板を１１００℃×３０秒（均熱）
なる処理後、９００℃まで徐冷した後急冷する中間焼鈍
を施し、次いで圧下率約７８％で冷却し、０．３３５mm
厚の冷延板とした。[Example 4] C: 0.045% by weight, S
i: 3.25% by weight, Mn: 0.15% by weight, S: 0.
007% by weight, acid-soluble Al: 0.030% by weight, N:
A 40 mm thick slab containing 0.0087 wt% and Sn: 0.050 wt% and the balance Fe and unavoidable impurities was heated at a temperature of 1150 ° C. for 60 minutes and immediately hot-rolled to a thickness of 2.3 mm. It was used as a hot rolled sheet. The hot-rolled sheet was pickled and then cold-rolled at a rolling reduction of about 34% to a thickness of 1.52 mm. After that, the steel plate was heated at 1100 ° C for 30 seconds (soaking).
After the above treatment, an intermediate annealing is performed in which the material is gradually cooled to 900 ° C and then rapidly cooled, and then cooled at a reduction rate of about 78% to obtain a thickness of 0.335 mm.
It was a thick cold-rolled sheet.
【００３５】この冷延板に８２０℃×１５０秒（均熱）
なる脱炭焼鈍を施した。脱炭焼鈍後の鋼板の平均粒径
（円相当直径）は２１μｍであった。次いでこの鋼板
に、７５０℃に３０秒保持する熱処理中、雰囲気ガス
中にＮＨ3 ガスを混入させて窒化処理，処理なしの２
条件の処理を施した。条件の窒化後の鋼板のＮ量は、
０．０１２４重量％であった。その後、ＭｇＯを主成分
とする焼鈍分離剤を塗布し、１５／hrで１２００℃まで
昇温し、１２００℃に２０時間保持する最終仕上焼鈍を
施した。この時１２００℃の２０時間保定においては、
Ｈ2 １００％なる焼鈍雰囲気中で行い、昇温過程では
ａ：Ｎ2 ２５％、Ｈ2 ７５％，ｂ：Ｈ2 １００％なる２
水準の雰囲気条件とした。なお、最終仕上焼鈍中の９０
０℃から１２００℃までの間に２５℃間隔で試料を炉か
ら取り出し、二次再結晶開始直前の試料のＮ量を調査し
た。窒化処理を施していない試料については、二次再結
晶が生じなかった。窒化処理を施した試料については、
雰囲気ａの場合、１０５０℃で二次再結晶粒が観察さ
れ、１０２５℃での鋼板（二次再結晶開始直前）のＮ量
は、０．０１４６重量％であった。一方、雰囲気ｂの場
合、１０７５℃で二次再結晶粒が観察され、１０５０℃
での鋼板（二次再結晶開始直前）のＮ量は、０．００９
５重量％であった。実験条件と製品の磁気特性を表４に
示す。This cold-rolled sheet was heated at 820 ° C. for 150 seconds (soaking).
Decarburization annealing was applied. The average grain size (equivalent circle diameter) of the steel sheet after decarburization annealing was 21 μm. Then, during the heat treatment of holding this steel plate at 750 ° C. for 30 seconds, NH 3 gas was mixed in the atmosphere gas to perform nitriding treatment and no treatment.
The condition was processed. The N content of the steel sheet after nitriding under the conditions is
It was 0.0124% by weight. After that, an annealing separator containing MgO as a main component was applied, the temperature was raised to 1200 ° C. at 15 / hr, and final finishing annealing was performed at 1200 ° C. for 20 hours. At this time, in a 20-hour retention at 1200 ° C,
It is performed in an annealing atmosphere of H 2 100%, and in the temperature rising process, a: N 2 25%, H 2 75%, b: H 2 100% 2.
The standard atmosphere conditions were used. In addition, 90 during final finish annealing
Samples were taken out of the furnace at intervals of 25 ° C. from 0 ° C. to 1200 ° C., and the N content of the samples immediately before the start of secondary recrystallization was investigated. Secondary recrystallization did not occur in the sample that was not subjected to the nitriding treatment. For samples that have undergone nitriding,
In the atmosphere a, secondary recrystallized grains were observed at 1050 ° C., and the N content of the steel sheet at 1025 ° C. (immediately before the start of secondary recrystallization) was 0.0146 wt%. On the other hand, in the case of the atmosphere b, secondary recrystallized grains were observed at 1075 ° C and 1050 ° C.
The N content of the steel sheet (immediately before the start of secondary recrystallization) was 0.009.
It was 5% by weight. Table 4 shows the experimental conditions and the magnetic properties of the products.
【００３６】[0036]
【表４】 [Table 4]
【００３７】［実施例５］Ｃ：０．０４８重量％、Ｓ
ｉ：３．３１重量％、Ｍｎ：０．１５重量％、Ｓ：０．
００７重量％、酸可溶性Ａｌ：０．０３１重量％、Ｎ：
０．００６９重量％を含有し、残部Ｆｅ及び不可避的不
純物からなる４０mm厚スラブを１１５０℃の温度で６０
分加熱した後、直ちに熱延を行い、２．３mm厚の熱延板
とした。この熱延板を酸洗し、次いで圧下率約４９％で
冷延し、１．１８mm厚の冷延板とした。しかる後、この
冷延板に１０５０℃×３０秒（均熱）なる処理後、９０
０℃まで徐冷した後急冷する中間焼鈍を施し、次いで圧
下率約７８％で冷却し、０．２６０mm厚の冷延板とし
た。[Example 5] C: 0.048% by weight, S
i: 3.31% by weight, Mn: 0.15% by weight, S: 0.
007% by weight, acid-soluble Al: 0.031% by weight, N:
A 40 mm thick slab containing 0.0069% by weight and the balance Fe and unavoidable impurities at a temperature of 1150 ° C.
Immediately after heating for a minute, hot rolling was performed to obtain a hot rolled sheet having a thickness of 2.3 mm. The hot rolled sheet was pickled and then cold rolled at a rolling reduction of about 49% to obtain a cold rolled sheet having a thickness of 1.18 mm. Thereafter, the cold-rolled sheet was treated at 1050 ° C. for 30 seconds (soaking), then 90
An intermediate annealing was performed in which the steel was gradually cooled to 0 ° C. and then rapidly cooled, and then cooled at a rolling reduction of about 78% to obtain a 0.260 mm-thick cold-rolled sheet.
【００３８】この冷延板にａ：８２０℃×１５０秒（均
熱），ｂ：８５０℃×１５０秒（均熱）なる２水準の脱
炭焼鈍を施した。この場合、一次再結晶粒の平均粒径
（円相当直径）はａ：２１μｍ，ｂ：２４μｍであっ
た。かかる鋼板に実施例１記載の窒化処理を施した。
窒化後の鋼板のＮ量は、０．０１９５〜０．０２１０重
量％であった。その後、ＭｇＯを主成分とする焼鈍分離
剤を塗布し、１０／hrで１２００℃まで昇温し、１２０
０℃に２０時間保持する最終仕上焼鈍を施した。この時
１２００℃の２０時間保定においては、Ｈ2 １００％な
る焼鈍雰囲気中で行い、昇温過程ではａ：Ｎ2 ２５％、
Ｈ2 ７５％，ｂ：Ｎ2 ７５％、Ｈ2 ２５％なる２水準の
雰囲気条件とした。なお、最終仕上焼鈍中に実施例４記
載の条件で試料を炉から取り出し、二次再結晶開始直前
の試料のＮ量を調査した。脱炭焼鈍条件ａで最終仕上焼
鈍の雰囲気条件Ａの場合、１０５０℃で二次再結晶粒が
観察され、１０２５℃での鋼板（二次再結晶開始直前）
のＮ量は、０．０１９８重量％であった。脱炭焼鈍条件
ａで最終仕上焼鈍の雰囲気条件Ｂの場合、１０７５℃で
二次再結晶粒が観察され、１０５０℃での鋼板（二次再
結晶開始直前）のＮ量は、０．０２５４重量％であっ
た。脱炭焼鈍条件ｂで最終仕上焼鈍の雰囲気条件Ａの場
合、１０７５℃で二次再結晶粒が観察され、１０５０℃
での鋼板（二次再結晶開始直前）のＮ量は、０．０１８
４重量％であった。脱炭焼鈍条件ｂで最終仕上焼鈍の雰
囲気条件Ｂの場合、１１００℃で二次再結晶粒が観察さ
れ、１０７５℃での鋼板（二次再結晶開始直前）のＮ量
は、０．０２４５重量％であった。実験条件と製品の磁
気特性を表５に示す。This cold-rolled sheet was subjected to two levels of decarburization annealing: a: 820 ° C. × 150 seconds (soaking), b: 850 ° C. × 150 seconds (soaking). In this case, the average grain size (equivalent circle diameter) of the primary recrystallized grains was a: 21 μm, b: 24 μm. This steel sheet was subjected to the nitriding treatment described in Example 1.
The N content of the steel sheet after nitriding was 0.0195 to 0.0210% by weight. After that, an annealing separating agent containing MgO as a main component is applied, and the temperature is raised to 1200 ° C. at 10 / hr, and 120
A final finish annealing was carried out at 0 ° C for 20 hours. At this time, the temperature was kept at 1200 ° C. for 20 hours in an annealing atmosphere of H 2 100%, and in the temperature rising process, a: N 2 25%,
H 2 75%, b: N 2 75%, and H 2 25% were set as two levels of atmospheric conditions. During the final finish annealing, the sample was taken out from the furnace under the conditions described in Example 4, and the N content of the sample immediately before the start of secondary recrystallization was investigated. In the case of decarburizing annealing condition a and final finishing annealing atmosphere condition A, secondary recrystallized grains were observed at 1050 ° C., and a steel plate at 1025 ° C. (immediately before the start of secondary recrystallization)
The amount of N was 0.0198% by weight. In the case of decarburization annealing condition a and final finishing annealing atmosphere condition B, secondary recrystallized grains were observed at 1075 ° C., and the N content of the steel plate at 1050 ° C. (immediately before the start of secondary recrystallization) was 0.0254 wt. %Met. In the case of decarburization annealing condition b and final finishing annealing atmosphere condition A, secondary recrystallized grains are observed at 1075 ° C. and 1050 ° C.
The N content of the steel sheet (immediately before the start of secondary recrystallization) was 0.018
It was 4% by weight. In the case of decarburization annealing condition b and final finishing annealing atmosphere condition B, secondary recrystallized grains are observed at 1100 ° C., and the N content of the steel plate at 1075 ° C. (immediately before the start of secondary recrystallization) is 0.0245 wt. %Met. Table 5 shows the experimental conditions and the magnetic properties of the products.
【００３９】[0039]
【表５】 [Table 5]
【００４０】[0040]
【発明の効果】以上説明したように、本発明において、
２回以上の冷延を行うプロセスの最終冷延の圧下率を６
０〜７９％とし、脱炭焼鈍完了後、最終仕上焼鈍開始ま
での間での一次再結晶粒径を１０〜３５μｍとし、熱延
後最終仕上焼鈍の二次再結晶開始までの間に鋼板に窒化
処理を施し、さらには二次再結晶開始直前での鋼板のＮ
量を制御することにより、低温スラブ加熱条件で、良好
な磁気特性を安定して得られるので、その工業的効果は
極めて大である。As described above, in the present invention,
The final cold rolling reduction rate of the process of performing cold rolling two or more times is 6
0 to 79%, the primary recrystallization grain size is 10 to 35 μm after the completion of decarburization annealing and before the start of final finish annealing, and after hot rolling, the steel sheet is formed before the start of secondary recrystallization of final finish annealing. Nitriding treatment was performed, and N of the steel sheet immediately before the start of secondary recrystallization
By controlling the amount, good magnetic properties can be stably obtained under the low temperature slab heating condition, so that its industrial effect is extremely large.
【図１】一次再結晶粒径（円相当直径）と製品の磁束密
度の関係を表す図である。FIG. 1 is a diagram showing a relationship between a primary recrystallized grain size (equivalent circle diameter) and a magnetic flux density of a product.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成４年１１月１７日[Submission date] November 17, 1992
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１４[Correction target item name] 0014
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１４】図１に示した如き関係が成立する理由につ
いては必ずしも明らかではないが、本発明者らは次のよ
うに推察している。すなわち、二次再結晶方位に対する
一次再結晶集合組織の影響メカニズムは、対応方位とい
う概念を用いて説明できると考えられる。本発明の如き
６０〜７９％の低圧下率最終冷延の場合、一次再結晶集
合組織は、それほど尖鋭には発達しない。従って、二次
再結晶方位に対する対応方位もそれほど強くならない。
この様な場合、二次再結晶する核の存在量とそれに対す
る対応方位の量の積の多い核が二次再結晶しやすいと考
えられる。この時、上記の積の二次再結晶に必要な臨界
値が重要となり、この臨界値が高過ぎると、二次再結晶
が起こらず、低過ぎると、様々な方位を持つ二次再結晶
粒が発生することとなる。そして、一次再結晶粒径の逆
数は、二次再結晶粒の粒成長の駆動力に比例する量と考
えられるので、一次再結晶の平均粒径が小さいほど、上
臨界値が低く、大きいほど臨界値が高いと考えれる。従
って図１に示した如く、１０〜３５μｍに一次再結晶の
平均粒径の適性値が存在したものといえる。１０μｍ超
の場合、何れも、二次再結晶が不良となっており、上記
臨界値の適性範囲と一次再結晶粒径の適性範囲が対応し
ているものと解される。Although the reason why the relationship shown in FIG. 1 is established is not always clear, the present inventors presume as follows. That is, for the secondary recrystallization orientation
The mechanism of influence of primary recrystallization texture can be explained by using the concept of corresponding orientation. In the case of 60-79% low pressure final cold rolling as in the present invention, the primary recrystallization texture does not develop so sharply. Therefore, the orientation corresponding to the secondary recrystallization orientation does not become so strong.
In such a case, it is considered that the nuclei having a large product of the abundance of the secondary recrystallized nuclei and the corresponding orientation amount are likely to be secondary recrystallized. At this time, the critical value required for secondary recrystallization of the above product becomes important, and if this critical value is too high, secondary recrystallization
Does not occur and is too low, secondary recrystallized grains having various orientations will be generated. Since the reciprocal of the primary recrystallized grain size is considered to be proportional to the driving force of the grain growth of the secondary recrystallized grains, the smaller the average grain size of the primary recrystallized grains, the lower the upper critical value, the larger the It seems that the critical value is high. Therefore, as shown in FIG. 1, it can be said that there is an appropriate value for the average particle size of primary recrystallization in the range of 10 to 35 μm. In the case where it exceeds 10 μm, the secondary recrystallization is poor in any case, and it is understood that the appropriate range of the critical value and the appropriate range of the primary recrystallized grain size correspond to each other.
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１７[Correction target item name] 0017
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１７】Ａｌは二次再結晶の安定化に必要なＡｌＮ
もしくは（Ａｌ，Ｓｉ）Ｎを確保するため、酸可溶性Ａ
ｌとして０．０１０％以上が必要である。酸可溶性Ａｌ
が０．０６０％を超えると熱延板のＡｌＮが不適切とな
り二次再結晶が不安定となるので０．０６０％以下とし
た。Al is AlN necessary for stabilizing secondary recrystallization.
Alternatively , in order to secure (Al, Si) N , acid-soluble A
0.01% or more is required as l. Acid soluble Al
Is more than 0.060%, the AlN of the hot-rolled sheet becomes unsuitable and the secondary recrystallization becomes unstable, so the content was made 0.060% or less.
【手続補正３】[Procedure 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２３[Name of item to be corrected] 0023
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００２３】かかる冷延後の鋼板は、通常の方法で脱炭
焼鈍、焼鈍分離剤塗布、最終仕上焼鈍を施されて最終製
品となる。ここで脱炭焼鈍完了後、最終仕上焼鈍開始ま
での間の一次再結晶粒の平均粒径を１０〜３５μｍとし
たのは、図１に示した如くこの値の範囲でＢ8 （Ｔ）≧
１．８５なる良好な磁束密度が得られるからである。そ
して、熱延後最終仕上焼鈍の二次再結晶開始までの間に
鋼板に窒化処理を施すと規定したのは、本発明の如き低
温スラブ加熱を前提とするプロセスでは、二次再結晶に
必要なインヒビター強度が不足がちになるからである。
窒化の方法としては特に限定するものではなく、脱炭焼
鈍後引き続き焼鈍雰囲気にＮＨ3 ガスを混入させ窒化す
る方法、プラズマを用いる方法、焼鈍分離剤に窒化物を
添加し、最終仕上焼鈍の昇温中に窒化物が分解してでき
た窒素を鋼板に吸収させる方法、最終仕上焼鈍の雰囲気
のＮ2 分圧を高めとし、鋼板を窒化する方法等何れの方
法でも良い。窒化量については特に限定するものではな
いが、１ppm 以上は必要である。The steel sheet after cold rolling is subjected to decarburization annealing, application of an annealing separating agent, and final finishing annealing by a usual method to obtain a final product. The average grain size of the primary recrystallized grains after completion of decarburization annealing and before the start of final finishing annealing is set to 10 to 35 μm as shown in FIG. 1 within the range of B 8 (T) ≧
This is because a good magnetic flux density of 1.85 can be obtained. Then, it is defined that the steel sheet is subjected to the nitriding treatment before the start of the secondary recrystallization of the final finish annealing after the hot rolling, in the process premised on the low temperature slab heating as in the present invention, it is necessary for the secondary recrystallization. This is because the inhibitor strength tends to be insufficient.
The nitriding method is not particularly limited, and a method of denitrifying and then subsequently nitriding by mixing NH 3 gas in an annealing atmosphere, a method of using plasma, a method of adding a nitride to an annealing separator and adding a final finishing annealing step Any method such as a method of absorbing nitrogen formed by decomposition of nitrides in the temperature into the steel sheet or a method of nitriding the steel sheet by increasing the N 2 partial pressure in the atmosphere of final annealing is applicable. The nitriding amount is not particularly limited, but 1 ppm or more is necessary.
【手続補正４】[Procedure amendment 4]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００４０[Item name to be corrected] 0040
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００４０】[0040]
【発明の効果】以上説明したように、本発明において、
２回以上の冷延を行うプロセスの最終冷延の圧下率を６
０〜７９％とし、脱炭焼鈍完了後、最終仕上焼鈍開始ま
での間での一次再結晶粒の平均粒径を１０〜３５μｍと
し、熱延後最終仕上焼鈍の二次再結晶開始までの間に鋼
板に窒化処理を施し、さらには二次再結晶開始直前での
鋼板のＮ量を制御することにより、低温スラブ加熱条件
で、良好な磁気特性を安定して得られるので、その工業
的効果は極めて大である。As described above, in the present invention,
The final cold rolling reduction rate of the process of performing cold rolling two or more times is 6
0 to 79%, the average grain size of the primary recrystallized grains is 10 to 35 μm after the completion of decarburization annealing and before the start of final finish annealing, and after the hot rolling until the start of secondary recrystallization of final finish annealing. By nitriding the steel sheet and controlling the N content of the steel sheet immediately before the start of secondary recrystallization, good magnetic properties can be stably obtained under low-temperature slab heating conditions. Is extremely large.
【手続補正５】[Procedure Amendment 5]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】図面の簡単な説明[Name of item to be corrected] Brief description of the drawing
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【図面の簡単な説明】[Brief description of drawings]
【図１】一次再結晶粒の平均粒径（円相当直径）と製品
の磁束密度の関係を表す図である。FIG. 1 is a diagram showing the relationship between the average grain size (equivalent circle diameter) of primary recrystallized grains and the magnetic flux density of a product.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０１Ｆ 1/16 Ｂ 7371−5Ｅ (72)発明者 河野 彪 福岡県北九州市戸畑区飛幡町１番１号 新 日本製鐵株式会社八幡製鐵所内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification number Internal reference number FI technical display location H01F 1/16 B 7371-5E (72) Inventor Akira Kono No. 1 Hibata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka No. 1 inside Nippon Steel Co., Ltd. Yawata Works
Claims (2)
ブを、１２８０℃未満の温度で加熱した後、熱延し、得
られた熱延板を圧下率６０〜７９％の最終冷延を含み、
必要に応じて中間焼鈍をはさむ２回以上の冷延を行い、
次いで脱炭焼鈍、最終仕上焼鈍を施して一方向性電磁鋼
板を製造する方法において、脱炭焼鈍完了後、最終仕上
焼鈍開始までの一次再結晶粒の平均粒径を１０〜３５μ
ｍとし、熱延後、最終仕上焼鈍の二次再結晶開始までの
間に鋼板に窒化処理を施すことを特徴とする磁気特性の
優れた一方向性電磁鋼板の製造方法。1. By weight%, C: 0.025 to 0.075%, Si: 2.5 to 4.5%, acid-soluble Al: 0.010 to 0.060%, N: 0.0010 to 0. After heating a slab containing 0.0130%, S + 0.405Se: 0.014% or less, Mn: 0.05 to 0.8% and the balance of Fe and inevitable impurities at a temperature of less than 1280 ° C., Hot-rolled, the resulting hot-rolled sheet including final cold rolling with a rolling reduction of 60 to 79%,
If necessary, perform cold rolling twice or more with intermediate annealing.
Then, in the method of producing a unidirectional electrical steel sheet by performing decarburization annealing and final finishing annealing, after decarburization annealing is completed, the average grain size of the primary recrystallized grains until the start of final finishing annealing is 10 to 35 μm.
m, a nitriding treatment is performed on the steel sheet after hot rolling and before the start of secondary recrystallization in the final finish annealing, a method for producing a unidirectional electrical steel sheet having excellent magnetic properties.
鋼板に、重量％でＮ：０．０１００％以上が含有される
ことを特徴とする請求項１記載の磁気特性の優れた一方
向性電磁鋼板の製造方法。2. A steel sheet immediately before the start of secondary recrystallization in the final finish annealing contains N: 0.0100% or more by weight%. Manufacturing method of grain-oriented electrical steel sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3281071A JPH05156361A (en) | 1991-10-28 | 1991-10-28 | Manufacture of grain-oriented electric steel sheet excellent in magnetic property |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3281071A JPH05156361A (en) | 1991-10-28 | 1991-10-28 | Manufacture of grain-oriented electric steel sheet excellent in magnetic property |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05156361A true JPH05156361A (en) | 1993-06-22 |
Family
ID=17633915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3281071A Withdrawn JPH05156361A (en) | 1991-10-28 | 1991-10-28 | Manufacture of grain-oriented electric steel sheet excellent in magnetic property |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05156361A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0726328A1 (en) * | 1995-02-13 | 1996-08-14 | Kawasaki Steel Corporation | Method of manufacturing grain-oriented silicon steel sheet having excellent characteristics |
| US5720196A (en) * | 1995-04-18 | 1998-02-24 | Kawasaki Steel Corporation | Hot-rolling method of steel piece joint during continuous hot-rolling |
| CN100455690C (en) * | 2005-11-30 | 2009-01-28 | 宝山钢铁股份有限公司 | Oriented silicon steel based on thin slab continuous casting and rolling and its manufacturing method |
-
1991
- 1991-10-28 JP JP3281071A patent/JPH05156361A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0726328A1 (en) * | 1995-02-13 | 1996-08-14 | Kawasaki Steel Corporation | Method of manufacturing grain-oriented silicon steel sheet having excellent characteristics |
| US5665178A (en) * | 1995-02-13 | 1997-09-09 | Kawasaki Steel Corporation | Method of manufacturing grain-oriented silicon steel sheet having excellent magnetic characteristics |
| US5720196A (en) * | 1995-04-18 | 1998-02-24 | Kawasaki Steel Corporation | Hot-rolling method of steel piece joint during continuous hot-rolling |
| CN100455690C (en) * | 2005-11-30 | 2009-01-28 | 宝山钢铁股份有限公司 | Oriented silicon steel based on thin slab continuous casting and rolling and its manufacturing method |
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