JPH08199239A - Production of grain oriented magnetic steel sheet with high magnetic flux density - Google Patents

Abstract

PURPOSE: To produce a grain oriented magnetic steel sheet excellent in magnetic properties and surface characteristic, free from edge crack, and having high magnetic flux density by applying specific N addition to a steel containing specific amounts of Si, Al, V, and S and further applying specific secondary recrystallization annealing. CONSTITUTION: A steel stab, containing, by weight, 1-4% Si, 0.01-0.05% Al, 0.01-0.10% V, an <=0.01% S and further containing, if necessary, 0.008-0.08% Nb, is soaked to 1000-1270 deg.C and hot-rolled. After finishing temp. is regulated to <=850 deg.C, cold rolling and primary and secondary recrystallization annealings are done. Further, 0.01-0.04% N is added to the molten steel or the steel before a secondary recrystallization annealing temp. of 950 deg.C is reached. At this time, (ξ) represented by ξ=N-14/51V, (η) represented by η=Al-27/14ξ, and primary recrystallization annealing temp. To are regulated so that they satisfy inequalities I, II, and III. Moreover, secondary recrystallization annealing is done at (0.1 to 80) deg.C/hr temp. rise rate with or without the addition of 0.05-5.0% Sb compound to MgO for forming forsterite or at (5 to 400) deg.C/hr temp. rise rate with the addition of 0.05-5.0% B compound, etc.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は磁気特性および表面特性
に優れた方向性珪素鋼板の製造法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a grain-oriented silicon steel sheet having excellent magnetic properties and surface properties.

【０００２】[0002]

【従来の技術】トランス用等の磁気特性に優れた珪素鋼
板を製造するに際して、高磁束密度特性の鋼に絶縁特性
と鋼板表面に張力を与えトランスの性能向上に必要な磁
気特性を向上させ、かつ鋼板との密着性が良好なフォル
ステライトと呼ばれる一次被膜を形成させることは大変
重要である。通常の技術では脱炭を伴う一次焼鈍後に鋼
板にマグネシアと呼ばれる酸化マグネシウム（ＭｇＯ）
の微粉末を水溶させたスラリー状のものを塗布し、必要
に応じて乾燥させた後、二次再結晶焼鈍工程で焼成さ
せ、鋼板中のＳｉとの反応でフォルステライト（Ｍｇ₂
ＳｉＯ₄ ）と呼ばれるセラミックス質状の絶縁被膜（一
次被膜）を形成させる。これが鋼板に張力を与え、磁気
特性とりわけ鉄損や磁歪と呼ばれるトランスの効率や騒
音特性を支配する特性値を向上させるのに有効である。
しかも、このフォルステライト形成の状態が、二次再結
晶で鋼板の結晶方位を通称Ｇｏｓｓ方位と呼ばれ、透磁
率や磁束密度の向上に不可欠な鋼板長手方向（圧延方
向）に対して｛１１０｝〈００１〉の結晶方位を有する
やや粗大な二次再結晶粒を成長させるのにも重要な役割
を果たしていることもよく知られている。2. Description of the Related Art When manufacturing a silicon steel sheet having excellent magnetic characteristics for transformers, etc., the steel having high magnetic flux density characteristics is provided with insulating characteristics and tension on the surface of the steel sheet to improve the magnetic characteristics necessary for improving the performance of the transformer. Moreover, it is very important to form a primary coating called forsterite that has good adhesion to the steel sheet. In the usual technology, magnesium oxide (MgO) called magnesia is applied to the steel sheet after the primary annealing accompanied by decarburization.
Of the fine powder of water is applied, dried as needed, and then fired in the secondary recrystallization annealing step. Forsterite (Mg ₂
A ceramic-like insulating coating (primary coating) called SiO ₄ ) is formed. This is effective for giving tension to the steel sheet and improving the magnetic characteristics, particularly iron loss and magnetostriction, which are characteristics of the transformer that control efficiency and noise characteristics.
In addition, this state of forsterite formation is called the Goss orientation in the crystal orientation of the steel sheet in the secondary recrystallization, and is {110} with respect to the steel sheet longitudinal direction (rolling direction) that is essential for improving the magnetic permeability and the magnetic flux density. It is also well known that it also plays an important role in growing slightly coarse secondary recrystallized grains having a <001> crystal orientation.

【０００３】すなわち、二次再結晶焼鈍昇温過程中に十
分緻密な被膜が形成されないまま二次再結晶させようと
しても、鋼板内のインヒビターと呼ばれる微細な窒化物
や硫化物等がそのままの状態で、あるいは分解して早く
鋼板外に抜け出てしまう。このため、昇温中にＧｏｓｓ
方位粒を優先的に成長させ、他の方位粒の成長を抑制さ
せる役目のインヒビター効果が発揮できず、通称、細粒
と呼ばれ、Ｇｏｓｓ方位粒の二次再結晶粒の成長が部分
的あるいは全面的に行われない、極めて磁気特性の劣る
鋼板を生み出すことになる。なお、このＭｇＯの中に酸
化チタン（ＴｉＯ₂ 等）やその他の化合物を添加させ、
さらに緻密な一次被膜を形成させることも行われる。That is, even if an attempt is made to carry out secondary recrystallization without forming a sufficiently dense film during the secondary recrystallization annealing temperature rising process, fine nitrides, sulfides, etc. called inhibitors in the steel sheet remain as they are. Or, it disassembles and quickly escapes from the steel plate. Therefore, during the temperature rise, Goss
Since the inhibitor effect of the role of preferentially growing the oriented grains and suppressing the growth of other oriented grains cannot be exhibited, it is commonly called fine grain, and the growth of the secondary recrystallized grains of the Goss oriented grains is partially or It will produce a steel sheet with extremely inferior magnetic properties, which is not done entirely. In addition, titanium oxide (TiO ₂ etc.) and other compounds are added to this MgO,
It is also performed to form a denser primary coating.

【０００４】一方、方向性電磁鋼板の重要な特性に磁束
密度と呼ばれる鋼の単位面積当たりにどの程度の磁束を
蓄え得るか、の目安を表す磁気特性値があり、これが高
いほど高透磁率で磁化特性や磁歪特性に優れ、かつとり
わけ磁区制御後の鉄損が小さくできることを示す。通常
８００A/m 程度の磁界を与えたときの磁束密度（Ｂ
₈（単位：Ｔまたはテスラ）と慣用的に表す）が高いほ
ど、磁性が良いというような表現をする。この磁束密度
が高いだけでは低鉄損や低磁歪は得られず、磁束密度が
高く、かつ被膜張力が大きいことが低鉄損および低磁歪
に好ましいとされている。つまり、高磁束密度とともに
良好な一次被膜の形成で被膜張力の大きいことが揃うこ
とが方向性電磁鋼板の使用性能を著しく高め、これが本
発明の狙いでもある。On the other hand, an important characteristic of the grain-oriented electrical steel sheet is a magnetic characteristic value, which is a measure of how much magnetic flux can be stored per unit area of steel called magnetic flux density. The higher this value, the higher the magnetic permeability. It is shown that the magnetization and magnetostriction characteristics are excellent, and especially the iron loss after the magnetic domain control can be reduced. Magnetic flux density (B when a magnetic field of about 800 A / m is applied)
_The higher the ₈ (unit: T or Tesla), the better the magnetism. It is considered that low iron loss and low magnetostriction cannot be obtained only by high magnetic flux density, and high magnetic flux density and high coating tension are preferable for low iron loss and low magnetostriction. In other words, the high magnetic flux density and the formation of a good primary coating have a large coating tension, which significantly enhances the use performance of the grain-oriented electrical steel sheet, which is also the aim of the present invention.

【０００５】磁束密度を高めるにはＭｎＳやＡｌＮ等の
微細析出物をインヒビターとして使用することが公知で
ある。とりわけＡｌＮの有効な存在を可能にするために
一次焼鈍中や後に窒素添加する方法も公知である。しか
るに、実際は上記の技術知見があってもなおかつ十分な
一次被膜および高磁束密度のための良好な二次再結晶組
織を併せて安定して作ることは容易ではなく、さらなる
適正なインヒビターとなる元素の選択やフォルステライ
ト被膜形成のための技術の開発が必要であった。It is known to use fine precipitates such as MnS and AlN as inhibitors to increase the magnetic flux density. In particular, a method of adding nitrogen during or after the primary annealing is also known in order to enable the effective presence of AlN. However, in reality, even with the above technical knowledge, it is not easy to stably produce a sufficient primary coating and a good secondary recrystallized structure for high magnetic flux density, and it is an element that becomes a more appropriate inhibitor. It was necessary to develop a technology for selection of forsterite film and formation of forsterite film.

【０００６】[0006]

【発明が解決しようとする課題】ＭｎＳ等をＡｌＮと併
用する鋼ではＭｎＳ以外にもさらに有効にインヒビター
として活動せしめる他の元素の添加も行われ、それなり
に高い磁束密度の鋼を得ている。しかし、ＭｎＳを利用
する場合の最大の課題の一つは熱延板の耳割れである。
従って、ＭｎＳを使わず、熱延のスラブ加熱温度を比較
的低くし、ＡｌＮをインヒビターとして有効に使う必要
があるが、従来はこのような鋼でのＢ₈ ≧１．９４Ｔの
高磁束密度はたとえば一次被膜を形成させないような特
殊の製造法以外は困難と考えられてきた。本発明ではＭ
ｎＳをインヒビターとして積極的に使わず、耳割れも殆
どない方向性電磁鋼板の製造法を提供する。In the steel in which MnS and the like are used in combination with AlN, in addition to MnS, other elements that act more effectively as inhibitors are added to obtain steel with a reasonably high magnetic flux density. However, one of the biggest problems when using MnS is cracking of the hot rolled sheet.
Therefore, it is necessary to make the slab heating temperature of hot rolling relatively low and use AlN effectively as an inhibitor without using MnS. Conventionally, the high magnetic flux density of B ₈ ≧ 1.94T in such steel is For example, it has been considered difficult except for a special manufacturing method that does not form a primary coating. In the present invention, M
Provided is a method for producing a grain-oriented electrical steel sheet which does not use nS as an inhibitor positively and has little ear cracking.

【０００７】[0007]

【課題を解決するための手段】本発明はこのような課題
に対して以下の技術的知見を得たものである。高磁束密
度鋼を得るには二次再結晶で通称Ｇｏｓｓ方位と呼ばれ
る｛１１０｝〈００１〉の結晶方位を有する粗大な粒を
いかに先鋭に作るかが技術の要である。これは一つには
一次焼鈍組織の一次再結晶粒の大きさとインヒビターの
強さのバランスで決まることが知られているが、先鋭な
Ｇｏｓｓ方位の二次再結晶粒を得るにはさらにそのメカ
ニズムを詳細に追求することが重要でその一つに次の考
え方がある。The present invention has obtained the following technical knowledge with respect to such problems. In order to obtain a high magnetic flux density steel, it is essential for the technique to sharply form coarse grains having a crystal orientation of {110} <001>, which is commonly called a Goss orientation, in secondary recrystallization. It is known that this is partly determined by the balance between the size of the primary recrystallized grains in the primary annealed structure and the strength of the inhibitor, but the mechanism is still more important for obtaining the secondary recrystallized grains with a sharp Goss orientation. It is important to pursue in detail and one of them is the following way of thinking.

【０００８】二次再結晶焼鈍において一次焼鈍組織の中
のＧｏｓｓ核の方位｛１１０｝〈００１〉を有する一次
再結晶粒のみが優先的に成長し、他の方位の粒成長がイ
ンヒビターでうまく抑制されるためには、二次再結晶初
期の比較的低い温度（１０００℃前後）での有効なイン
ヒビターの存在が必要であり、これを従来のＭｎＳやＭ
ｎＳの役割を助長する添加元素をＡｌＮと併用する技術
が種々発明されてきた。しかしながら前述のようにＭｎ
Ｓを主として使用する鋼は熱延耳割れが避けられず、か
つ、ＭｎＳを固溶させる目的等でスラブ加熱温度を１３
００℃以上にする等の工業的困難さを伴うことがあり、
従って熱延耳割れがないかあっても極めて小さい鋼でか
つスラブ加熱温度も低くできるようにするためには、そ
れに代替する新たな技術が必要であった。In the secondary recrystallization annealing, only the primary recrystallized grains having the orientation {110} <001> of Goss nuclei in the primary annealed structure grow preferentially, and grain growth in other orientations is well suppressed by the inhibitor. In order to be effective, the existence of an effective inhibitor at a relatively low temperature (around 1000 ° C.) in the initial stage of secondary recrystallization is required.
Various techniques have been invented in which an additive element that promotes the role of nS is used in combination with AlN. However, as described above, Mn
Steel using S as a main component is inevitable with hot-rolled ear cracks, and the slab heating temperature is set to 13 for the purpose of forming a solid solution with MnS.
There may be industrial difficulties such as making it over 00 ℃,
Therefore, in order to make it possible to reduce the slab heating temperature with extremely small steel even with or without hot-rolled ear cracks, a new technology to replace it was necessary.

【０００９】本発明の知見の一つはＶおよび／あるいは
Ｎｂの利用である。ＶはＮと化合しＶＮを形成する。こ
れの分解温度はＳｉ₃ Ｎ₄ （９００〜９５０℃前後）と
ＡｌＮ（１０７０〜１１００℃前後）の中間で約１００
０℃前後である。これはＭｎＳのそれにも近い。また、
Ｎｂの窒化物のそれはＶより少し高く１０３０℃前後で
あるが、Ｖに次ぐ効果が期待される。この分解温度がＡ
ｌＮより低いということはやがてＡｌＮがインヒビター
としての役割を高温域で受け継いで、Ｇｏｓｓ方位の二
次再結晶粒がさらなる成長をするための、いわばＧｏｓ
ｓ核の萌芽期の重要なコントロールの役割に相当してい
る、とも言えるので初期インヒビターとも考えられる。
これに対しＡｌＮは後期インヒビターとも言える。従っ
て、ＡｌＮとの分解温度との差が高磁束密度に重要であ
る。さらに分解温度が低いことはインヒビターとしての
役割が終了した後で、自らの純化もしやすく鉄損を低く
するためにも重要である。One of the findings of the present invention is the use of V and / or Nb. V combines with N to form VN. Its decomposition temperature is about 100 between Si ₃ N ₄ (around 900 to 950 ° C) and AlN (around 1070 to 1100 ° C).
It is around 0 ° C. This is close to that of MnS. Also,
The Nb nitride is slightly higher than V and is around 1030 ° C., but an effect next to V is expected. This decomposition temperature is A
Since it is lower than 1N, AlN inherits its role as an inhibitor at a high temperature region and the secondary recrystallized grains in the Goss orientation further grow.
Since it can be said that it corresponds to an important control role of the s nucleus in the embryonic stage, it is considered to be an early inhibitor.
On the other hand, AlN can be said to be a late-stage inhibitor. Therefore, the difference from the decomposition temperature with AlN is important for high magnetic flux density. Furthermore, a low decomposition temperature is important in order to easily purify itself after the role as an inhibitor is finished and to reduce iron loss.

【００１０】ところが、本発明で明らかになったのは、
単にＶやＮｂの発見だけではＢ₈ ≧１．９４ＴのＢ₈ や
良好な一次被膜ができないという事実である。これを克
服したのが本発明の最大の知見の一つである。まず、重
要なのは、ξ＝Ｎ％−（１４／５１）Ｖ％の概念であ
る。なお本発明で％は重量％（wt％）を意味する。これ
はＶＮが生成された残りのＮの量を示すが、本発明によ
りＶＮが生成され初期インヒビターとしての役割があっ
ても、残りのＮが後期インヒビターのＡｌＮの形成にあ
る程度十分確保されていないと、先鋭なＧｏｓｓ二次再
結晶粒の成長を引き継げないことが分かったものであ
る。このためにはξは最低０．００２％必要である。一
方、０．０４％超ではフリーのＮが多すぎてまず微細に
安定した初期インヒビターのＶＮの生成を抑制してしま
う。However, the present invention has revealed that
Simply discovery of V and Nb is the fact that can not be B ₈ and good primary film of B ₈ ≧ 1.94T. One of the greatest findings of the present invention is to overcome this. First, what is important is the concept of ξ = N% − (14/51) V%. In the present invention,% means% by weight (wt%). This shows the amount of residual N in which VN was produced, but even if the present invention produced VN and served as an early inhibitor, the residual N was not sufficiently secured for the formation of the late inhibitor AlN. It was found that the sharp growth of Goss secondary recrystallized grains could not be succeeded. For this, ξ must be at least 0.002%. On the other hand, if it exceeds 0.04%, the amount of free N is too large, and the production of VN which is a finely stable initial inhibitor is suppressed first.

【００１１】さらにξの規制だけでは高Ｂ₈ は得られな
いことが明らかになった。つまり、ＶＮの初期インヒビ
ターからＡｌＮの後期インヒビターへの引き継ぎがスム
ーズにいくためには、ＶやＡｌやＮが十分あればそれで
本発明の目的とする高Ｂ₈ の磁束密度が得られるという
わけにはいかないことが分かった。すなわちη＝Ａｌ％
−（２７／１４）ξという量がＶとの関係で極めて重要
なことが分かった。ηはＶＮが形成され、やがてＡｌＮ
も形成された後の残りのＡｌＮ量に対応するもので、い
わば鋼マトリックス中のＡｌの余裕存在量ないしはＡｌ
Ｎ形成に本来必要なＡｌの不足分の量（負符号）を表す
もので、いわば初期インヒビターのＶＮ等から後期イン
ヒビターＡｌＮへの移行の促進活性化の度合いを示して
いる。Further, it became clear that high B ₈ cannot be obtained only by controlling ξ. In other words, in order to smoothly carry over from the early inhibitor of VN to the late inhibitor of AlN, if V, Al, and N are sufficient, the magnetic flux density of high B _{8 that} is the object of the present invention can be obtained. I knew it wasn't. That is, η = Al%
It has been found that the quantity − (27/14) ξ is extremely important in relation to V. η formed VN, and eventually AlN
Also corresponds to the amount of remaining AlN after the formation, so to speak, the surplus existing amount of Al in the steel matrix or Al.
It represents the amount of Al deficiency originally required for N formation (negative sign), which means the degree of promotion activation of the transition from the early inhibitor VN or the like to the late inhibitor AlN, so to speak.

【００１２】従って、この値とＶ量との相対的な関係、
Ｖ％−η、はその値が大きいほど初期インヒビターのＶ
ＮがＡｌＮに対して安定して初期インヒビターの役割を
いかに十分果たすかを示しており、高磁束密度を狙う本
発明鋼ではＶ％−ηは最低０．００５％は必要である。
この値の大きいほどＶＮは安定しているが大きすぎる
と、後期インヒビターＡｌＮへのスムーズな移行がしに
くくなりＢ₈ ≧１．９４Ｔは困難となるため、Ｖ％−η
の上限が必要であり、本発明鋼においてはその最大値は
０．０７％となる。Therefore, the relative relationship between this value and the V amount,
V% −η, the larger the value, the V of the initial inhibitor
It shows how N stably plays a sufficient role as an initial inhibitor against AlN, and V% -η is required to be at least 0.005% in the steel of the present invention aiming at a high magnetic flux density.
The larger this value is, the more stable the VN is, but if it is too large, smooth transition to the late-stage inhibitor AlN becomes difficult and B ₈ ≧ 1.94T becomes difficult, so V% −η.
Is required, and the maximum value in the steel of the present invention is 0.07%.

【００１３】また、Ｖ％−ηが大きいと一次再結晶粒の
成長も抑制して高温の一次焼鈍温度まで一次再結晶粒を
小さく保つので、二次再結晶時の細粒化も抑える効果も
あるが、一方、大きすぎると殆ど一次再結晶粒は成長し
なくなる。一方、Ｖ％−ηは小さすぎても（負も含め）
良くない。このときはＶＮがＡｌＮに比べて不安定であ
り、初期インヒビターの作用が弱く、二次再結晶はして
も前述のようにＧｏｓｓの先鋭な方位が得られにくくＢ
₈ ≧１．９４Ｔは困難である。これらを含めると０．０
１％≦Ｖ％−η≦０．０５％が最も好ましい。これらの
関係を図示したのが図１である。Further, when V% -η is large, the growth of primary recrystallized grains is suppressed and the primary recrystallized grains are kept small up to the high temperature primary annealing temperature. However, on the other hand, if it is too large, the primary recrystallized grains hardly grow. On the other hand, if V% -η is too small (including negative)
Not good. At this time, VN is more unstable than AlN, the action of the initial inhibitor is weak, and even if the secondary recrystallization is performed, it is difficult to obtain the sharp Goss orientation as described above.
₈ ≧ 1.94T is difficult. 0.0 including these
Most preferably, 1% ≦ V% −η ≦ 0.05%. FIG. 1 illustrates these relationships.

【００１４】さらに本発明では高磁束密度を得るには一
次再結晶焼鈍温度をＶ％−ηと連動させて設けることが
必要であることが分かった。これは、Ｇｏｓｓの先鋭な
二次再結晶方位を得るには一次再結晶粒の大きさとイン
ヒビター強度のバランスが重要なためである。すなわち
一次再結晶粒が大きすぎると粒界駆動力が弱すぎていわ
ゆる二次再結晶せずに、いわゆる細粒の現象が起き、ま
た、粒が小さすぎるとＧｏｓｓ以外の方位も成長し、高
磁束密度は得られない。Further, in the present invention, it was found that it is necessary to provide the primary recrystallization annealing temperature in conjunction with V% -η in order to obtain a high magnetic flux density. This is because the balance between the size of the primary recrystallized grains and the inhibitor strength is important to obtain the sharp secondary recrystallization orientation of Goss. That is, if the primary recrystallized grains are too large, the grain boundary driving force is too weak and so-called secondary recrystallization does not occur, so-called fine grain phenomenon occurs, and if the grains are too small, orientations other than Goss grow and Magnetic flux density cannot be obtained.

【００１５】ＶＮは初期段階で一次再結晶粒の成長を抑
制するので先鋭なＧｏｓｓ粒を得るための最適な一次再
結晶粒を得るには、Ｖ％−ηに対応して焼鈍温度を高く
することが好ましい。逆にいえば、最適の高磁束密度を
得るには、一次再結晶焼鈍温度は初期インヒビター強度
に対応するＶ％−ηに連動させる必要があることが分か
った。本発明によれば一次再結晶焼鈍温度をＴ₀ （℃）
としたとき、７８０℃＋１００（Ｖ％−η）≦Ｔ₀ ≦７
８０℃＋５０００（Ｖ％−η）で行う必要がある。Ｔ₀
の下限は、これより低い温度では良好なＧｏｓｓ方位の
二次再結晶粒を得るのに十分な正常な一次再結晶粒の大
きさが得られず、一方、この上限より高いと一次再結晶
粒が粗大化し、二次再結晶で細粒が出始める。Ｇｏｓｓ
粒の均一な成長でさらなる高磁束密度を得るには好まし
くは７８０℃＋５００（Ｖ％−η）≦Ｔ₀ ≦７８０℃＋
３０００（Ｖ％−η）が良い。図２はこの関係を図示し
たものである。Since VN suppresses the growth of primary recrystallized grains in the initial stage, in order to obtain the optimum primary recrystallized grains for obtaining sharp Goss grains, the annealing temperature is increased corresponding to V% -η. It is preferable. Conversely, it was found that the primary recrystallization annealing temperature needs to be linked to V% -η corresponding to the initial inhibitor strength in order to obtain the optimum high magnetic flux density. According to the present invention, the primary recrystallization annealing temperature is set to T ₀ (° C)
, 780 ° C. + 100 (V% −η) ≦ T ₀ ≦ 7
It is necessary to carry out at 80 ° C. + 5000 (V% −η). T ₀
The lower limit of is that at a temperature lower than this, a normal primary recrystallized grain size sufficient to obtain good Goss-oriented secondary recrystallized grains cannot be obtained, while when it is higher than this upper limit, Becomes coarse and fine grains start to appear in the secondary recrystallization. Goss
To obtain a higher magnetic flux density by uniform grain growth, preferably 780 ° C. + 500 (V% −η) ≦ T ₀ ≦ 780 ° C. +
3000 (V% -η) is good. FIG. 2 illustrates this relationship.

【００１６】ここで７８０℃の意味はＶやＮｂを含まな
いときの基礎的な二次再結晶でＧｏｓｓ方位が得られる
本発明対象鋼の下限の一次再結晶焼鈍温度に相当するも
のである。ＮｂはＶほどではないが、それに準ずる効果
作用がある。ＮｂでＶを一部または全部を代替する場合
は、Ｎとの関係で原子量比から（５１／９３）Ｎｂ％が
Ｖの代替としての役割をする。一方、方向性電磁鋼板は
高磁束密度だけでは実際の使用に耐えられない。鋼板の
表面にフォルステライト被膜を十分に形成させないと、
鋼板に張力が得られないために、とりわけ磁区制御等を
して、鉄損を低くしようとしても磁区は細分化せずに低
鉄損を得られないばかりか、磁歪特性も劣ってしまう。Here, the meaning of 780 ° C. corresponds to the lower limit primary recrystallization annealing temperature of the steel of the present invention in which the Goss orientation can be obtained by basic secondary recrystallization when V and Nb are not contained. Although Nb is not as high as V, it has a similar effect. When Nb is partially or entirely substituted for V, (51/93) Nb% of the atomic weight ratio in relation to N serves as a substitute for V. On the other hand, grain-oriented electrical steel sheets cannot withstand actual use with high magnetic flux density alone. If the forsterite film is not formed sufficiently on the surface of the steel plate,
Since tension cannot be obtained in the steel sheet, even if magnetic domain control or the like is performed to reduce the iron loss, not only the magnetic domain is not subdivided but low iron loss cannot be obtained, but also the magnetostriction characteristic is deteriorated.

【００１７】さらに、電気的絶縁性も得られず、トラン
ス等の主力商品の使用には無理がある。従来技術におい
ても本発明鋼のようにＭｎＳ等を積極的に使用しない方
向性電磁鋼板でも、その使用目的から意図的に一次被膜
を形成させない場合は高磁束密度を得ることは比較的達
成可能であった。これは一つには二次再結晶焼鈍時にガ
ス雰囲気からのＮ等の補給を媒体とした補助インヒビタ
ー的役割に負う面と、一方、磁束密度そのものの測定が
厚い被膜がない方が高い値が得られやすいという面に負
うところも多かったためである。Furthermore, since electrical insulation is not obtained, it is impossible to use main products such as transformers. Even in the prior art, even with a grain-oriented electrical steel sheet that does not actively use MnS or the like like the steel of the present invention, it is relatively achievable to obtain a high magnetic flux density if the primary coating is not intentionally formed for the purpose of use. there were. This is due in part to the fact that it plays a role of an auxiliary inhibitor using the supply of N and the like from the gas atmosphere during secondary recrystallization annealing as a medium, and on the other hand, the measurement of the magnetic flux density itself is higher when there is no thick coating. This is because there were many points in which it was easy to obtain.

【００１８】本発明の狙いは通常の良好な一次被膜を持
ちつつ、低磁歪や低鉄損特性に優れた高磁束密度の方向
性電磁鋼板を得ることであり、このためには上記以外に
下記の本発明の知見が重要である。すなわち、二次再結
晶焼鈍の前に塗布するマグネシア（ＭｇＯ）や水酸化マ
グネシウムの中にアンチモン系の化合物やほう酸系の化
合物等を反応活性化のために使用し、かつ、この添加物
の種類によって二次再結晶焼鈍の昇温速度を最適にもっ
ていく必要があることを知見したのである。この詳細に
ついては後述する。本発明は、上記を骨子とする方法に
おいて従来技術における課題を解決し、熱延板の耳割れ
の殆どない方向性電磁鋼板で磁束密度Ｂ₈ ≧１．９４Ｔ
の良好なフォルステライト被膜のついた製品の製造方法
を提供するものである。The object of the present invention is to obtain a grain-oriented electrical steel sheet having a high magnetic flux density which is excellent in low magnetostriction and low iron loss characteristics while having an ordinary good primary coating. The findings of the present invention are important. That is, an antimony compound or a boric acid compound is used for reaction activation in magnesia (MgO) or magnesium hydroxide applied before the secondary recrystallization annealing, and the kind of this additive is used. Therefore, it was found that it is necessary to optimize the temperature rising rate of the secondary recrystallization annealing. The details will be described later. The present invention solves the problems in the prior art in a method using the above as the essence, and is a magnetic grain density B ₈ ≧ 1.94T in a grain-oriented electrical steel sheet with almost no cracks in the edge of the hot rolled sheet.
The present invention provides a method for producing a product with a good forsterite coating.

【００１９】本発明の要旨とするところは下記の通りで
ある。 （１）重量比で、Ｓｉ：１〜４％、Ａｌ：０．０１〜
０．０５％、Ｖ：０．０１〜０．１０％、Ｓ：０．０１
％以下を含む鋼を溶製し、１０００〜１２７０℃のスラ
ブ均熱温度、８５０℃以上の熱延仕上温度の熱間圧延、
冷間圧延、一次再結晶焼鈍および二次再結晶焼鈍を基本
工程とする方向性電磁鋼板の製造において、さらに溶鋼
中および熱間圧延後から二次再結晶焼鈍工程の二次再結
晶焼鈍温度９５０℃に到達する前のいずれかの工程で鋼
に合計Ｎ：０．０１〜０．０４％の窒素添加を行い、か
つその合計のＮ量に対してξ＝Ｎ％−（１４／５１）Ｖ
％と定義したとき０．００２％≦ξ≦０．０４％を満た
し、かつ、η＝Ａｌ％−（２７／１４）ξと定義したと
きＶ％−ηが０．００５％≦Ｖ％−η≦０．０７％を満
たすようにインヒビターを付与せしめ、さらに、一次再
結晶焼鈍温度Ｔ₀ を７８０℃＋１００（Ｖ％−η）≦Ｔ
₀ ≦７８０℃＋５０００（Ｖ％−η）で行い、かつ、上
記の二次再結晶焼鈍前にフォルステライトを主体とする
一次被膜形成のために塗布するマグネシアの中にアンチ
モン系の化合物を０．０５〜５．０％添加するか、ある
いはなにも意図的に添加しない場合は二次再結晶焼鈍で
の８００℃〜最高到達温度の平均昇温速度を毎時０．１
〜８０℃とし、一方、マグネシアの中にボロン系、スト
ロンチウム・バリウム系、炭・窒化物系、硫化物系、塩
化物系の１種または２種以上を合計０．０５〜５．０％
添加する場合は二次再結晶焼鈍での８００℃〜最高到達
温度の平均昇温速度を毎時５〜４００℃とすることを特
徴とする高磁束密度方向性電磁鋼板の製造法。The gist of the present invention is as follows. (1) By weight ratio, Si: 1-4%, Al: 0.01-
0.05%, V: 0.01 to 0.10%, S: 0.01
% Of slab, and slab soaking temperature of 1000 to 1270 ° C., hot rolling of hot rolling finishing temperature of 850 ° C. or more,
In the production of grain-oriented electrical steel sheet having cold rolling, primary recrystallization annealing and secondary recrystallization annealing as basic steps, the secondary recrystallization annealing temperature of the secondary recrystallization annealing step 950 in the molten steel and after hot rolling. Nitrogen was added to the steel in a total amount of 0.01 to 0.04% in any step before reaching ℃, and ξ = N% − (14/51) V with respect to the total amount of N.
When defined as%, 0.002% ≦ ξ ≦ 0.04% is satisfied, and when defined as η = Al% − (27/14) ξ, V% −η is 0.005% ≦ V% −η An inhibitor is added so as to satisfy ≦ 0.07%, and the primary recrystallization annealing temperature T ₀ is 780 ° C. + 100 (V% −η) ≦ T.
₀ ≦ 780 ° C. + 5000 (V% −η), and before the secondary recrystallization annealing described above, an antimony-based compound was added to magnesia to form a primary film mainly composed of forsterite. In the case of adding 0.5 to 5.0% or not intentionally, the average rate of temperature increase from 800 ° C. to the maximum attainable temperature in the secondary recrystallization annealing is 0.1 per hour.
〜80 ℃, while one or more of boron-based, strontium-barium-based, carbon / nitride-based, sulfide-based, chloride-based magnesia in total of 0.05-5.0%
A method for producing a high magnetic flux density grain-oriented electrical steel sheet, characterized in that when added, the average temperature rising rate from 800 ° C. to the maximum reached temperature in secondary recrystallization annealing is 5 to 400 ° C. per hour.

【００２０】（２）Ｎｂ：０．００８〜０．０８％を溶
鋼中に含み、また、（１）記載の式中のＶ％に代えてＶ
％＋（５１／９３）Ｎｂ％と置くことを特徴とする
（１）記載の製造法。 （３）Ｖの代わりにＮｂ：０．００８〜０．０８％を溶
鋼中に含み、また、（１）記載の式中のＶ％に代えて
（５１／９３）Ｎｂ％と置くことを特徴とする（１）記
載の製造法。(2) Nb: 0.008 to 0.08% is contained in the molten steel, and V is substituted for V% in the formula described in (1).
% + (51/93) Nb%. The production method according to (1), characterized in that (3) Nb: 0.008 to 0.08% is contained in the molten steel instead of V, and (51/93) Nb% is set instead of V% in the formula of (1). The manufacturing method according to (1).

【００２１】以下に本発明を詳細に説明する。前述のよ
うに方向性珪素鋼板の二次再結晶はＧｏｓｓ方位と呼ば
れる｛１１０｝〈００１〉方位の粒を二次再結晶焼鈍
（仕上焼鈍とも呼ばれる）時に十分成長させることが肝
要である。これは一次再結晶焼鈍（一次焼鈍とも呼ぶ）
の中のある特定粒（Ｇｏｓｓ粒）のみを粗大再結晶させ
るもので、このときにインヒビター（Ｉｎｈｉｂｉｔｏ
ｒ）と呼ばれるたとえばＭｎＳやＡｌＮのような微細析
出物を仕上焼鈍前に十分に作っておくことが技術上必要
であることがよく知られている。そして、このために必
要なＳやＮを鋼溶製時またはとりわけＮを一次焼鈍後ま
たは他の工程中に添加することが行われる。ここでＮを
添加する際の一次焼鈍後と呼ぶ内容を補足するが、これ
は通常脱炭反応も機能する一次焼鈍の設備の一部にアン
モニア、窒素化合物等により、あるいは物理的、化学的
蒸着法等により、窒化反応を行う設備を内部または近接
して設置し、一次焼鈍後またはそれと平行させて窒化反
応させる方法である。The present invention will be described in detail below. As described above, in the secondary recrystallization of the grain-oriented silicon steel sheet, it is important to sufficiently grow the grains having the {110} <001> orientation called the Goss orientation during the secondary recrystallization annealing (also called finish annealing). This is primary recrystallization annealing (also called primary annealing)
Among them, only certain specific grains (Goss grains) are coarsely recrystallized. At this time, an inhibitor (Inhibito) is used.
It is well known in the art that fine precipitates such as MnS and AlN called r) are sufficiently prepared before finish annealing. Then, S and N necessary for this purpose are added at the time of steel melting, or particularly N is added after primary annealing or during other steps. Here, the content referred to as "after primary annealing when adding N" is supplemented. This is because ammonia, nitrogen compounds, or physical or chemical vapor deposition is used in a part of the equipment for primary annealing that normally also functions for decarburization. This is a method in which the equipment for performing the nitriding reaction is installed inside or in the vicinity thereof by the method or the like, and the nitriding reaction is performed after the primary annealing or in parallel therewith.

【００２２】一次焼鈍は鋼の冷間圧延（冷延）後の組織
を焼鈍組織にし、最適な一次再結晶粒径を得る目的以外
に鋼の脱炭やそれに伴う、二次再結晶焼鈍時の一次被膜
（フォルステライト等）を良好に形成するための酸化層
を作る目的もある。鋼溶製時に十分低炭素化した鋼では
脱炭機能よりも一次焼鈍後の表面層の酸化物層を変え
て、被膜形成に有利な形にすることがむしろ重要な役割
となる。In the primary annealing, the structure after cold rolling (cold rolling) of steel is changed to an annealing structure to obtain an optimum primary recrystallized grain size, and in addition to decarburization of steel and accompanying secondary recrystallization annealing. It also has the purpose of forming an oxide layer for favorably forming a primary coating (forsterite, etc.). In the case of steel having a sufficiently low carbon content during steel melting, it is more important than the decarburizing function to change the oxide layer of the surface layer after the primary annealing so that the oxide film has an advantageous shape for film formation.

【００２３】さて一次焼鈍し、必要に応じて窒化した鋼
板にＭｇＯを主体とし、これを水に溶かして通称ＭｇＯ
パウダー水溶液というものをスラリー状に鋼板表面に塗
布し、次の仕上焼鈍工程で被膜生成および二次再結晶を
行わせしめる。図３は一次焼鈍および必要に応じて窒化
処理後の３％Ｓｉ鋼板にＭｇＯパウダーをスラリー状に
塗布して、二次再結晶焼鈍の８００℃〜最高到達温度の
平均昇温速度を変えて実験を行った結果である。Now, primary annealing is carried out, and if necessary, the steel sheet nitrided contains MgO as a main component, and this is dissolved in water to obtain a so-called MgO.
An aqueous powder solution is applied to the surface of the steel sheet in the form of a slurry, and film formation and secondary recrystallization are performed in the next finish annealing step. FIG. 3 shows an experiment in which MgO powder is applied in a slurry form on a 3% Si steel sheet after primary annealing and, if necessary, nitriding treatment, and the average temperature rising rate of secondary recrystallization annealing from 800 ° C. to the maximum reached temperature is changed. Is the result of doing.

【００２４】ここでパウダーにＳｂ系、Ｂ系とあるのは
ここではそれぞれＭｇＯパウダーに微量のＴｉＯ₂ （５
％）とＳｂ₂ （ＳＯ₄ ）₃ （０．２％）、ＴｉＯ₂ （５
％）とＮａ₂ Ｂ₄ Ｏ₇ （０．３％）を添加し、フォルス
テライト形成等を促進させたものである。ここで一次被
膜の形成状態を目視観察で二重丸（極めて良）、○（か
なり良）、△（一部はげている）、×（殆ど被膜ができ
てない）で分類した。なお、フォルステライトの生成は
ＭｇＯと鋼板中の表面濃化したＳｉが反応し、２ＭｇＯ
＋ＳｉＯ₂ →Ｍｇ₂ ＳｉＯ₄ の反応を起こしたものと一
般的に考えられている。Here, the powders are referred to as Sb-based and B-based, respectively. Here, a small amount of TiO ₂ (5
%), Sb ₂ (SO ₄ ) ₃ (0.2%), TiO ₂ (5
%) And Na ₂ B ₄ O ₇ (0.3%) were added to promote forsterite formation and the like. Here, the state of formation of the primary coating was visually classified into double circles (extremely good), ◯ (quite good), Δ (partially peeled), and × (almost no coating was formed). In addition, forsterite is produced by reacting MgO and surface-concentrated Si in the steel sheet with 2MgO.
It is generally considered that the reaction of + SiO ₂ → Mg ₂ SiO ₄ has occurred.

【００２５】図３の実験結果にみられるようにＳｂ系の
化合物をＭｇＯに微量添加した場合、ＭｇＯの溶融は比
較的低温で行われるので、たとえば二次再結晶焼鈍の８
００℃〜最高到達温度の平均昇温速度を比較的小さくし
た方がより早くフォルステライトの生成を促進させ、優
れた一次被膜を生成させやすいことが分かった。なおア
ンチモン（Ｓｂ）系の化合物とは当実験で用いたＳｂ₂
（ＳＯ₄ ）₃ のみならずＳｂを含む他の化合物でも類似
の効果が期待できる。As can be seen from the experimental results of FIG. 3, when a small amount of Sb-based compound is added to MgO, the melting of MgO is performed at a relatively low temperature.
It has been found that a relatively small average temperature increase rate from 00 ° C. to the maximum reached temperature accelerates the formation of forsterite more quickly and makes it easier to form an excellent primary coating. The antimony (Sb) -based compound is the Sb ₂ used in this experiment.
Similar effects can be expected with other compounds containing Sb as well as (SO ₄ ) ₃ .

【００２６】一方、同じ低融点化合物でもボロン（Ｂ）
系の化合物をＭｇＯに微量添加した場合は、ＭｇＯの溶
融はＳｂ系の化合物よりも比較的高温で行われるので、
たとえば二次再結晶焼鈍の８００℃〜最高到達温度の平
均昇温速度を比較的大きくした方がより早くフォルステ
ライトの生成を促進させる。なお、ボロン（Ｂ）系はこ
の例のＮａ系のみならずＮａの代わりにＣａ，Ｍｇ等を
含む化合物やほう酸（Ｈ₃ ＢＯ₃ ）やほう酸ソーダでも
類似の効果が期待できる。On the other hand, even with the same low melting point compound, boron (B)
When a trace amount of a system compound is added to MgO, the melting of MgO is performed at a relatively higher temperature than that of the Sb system compound.
For example, when the average temperature rising rate of the secondary recrystallization annealing from 800 ° C. to the maximum reached temperature is made relatively large, generation of forsterite is promoted faster. The boron (B) -based material is not limited to the Na-based material in this example, but a compound containing Ca, Mg or the like instead of Na, boric acid (H ₃ BO ₃ ) or sodium borate can be expected to have similar effects.

【００２７】さらに、アンチモン系よりも高融点系とい
う点でストロンチウム・バリウム系、炭・窒化物系、硫
化物系、塩化物系もボロン系と同等の作用が認められ
る。これらの化合物を総称してボロン系または非アンチ
モン系と呼ぶことにする。なお、通常ＭｇＯにはＴｉＯ
₂ 等の酸化物を添加させ高温反応を容易にすることがし
ばしば行われるが、本発明の上記の添加物の効果はその
酸化物の添加量に関係なく発揮されるのでＭｇＯにＴｉ
Ｏ₂ 酸化物が添加されるだけの場合も、これをプレイン
材と称してアンチモン系の化合物のベース材の一部とみ
なしている。Furthermore, strontium / barium type, carbon / nitride type, sulfide type, and chloride type substances have the same action as boron type in that they are higher melting point type than antimony type. These compounds will be collectively referred to as boron-based or non-antimony-based compounds. Note that TiO is usually used for MgO.
It is often the case that an oxide such as ₂ is added to facilitate the high temperature reaction. However, since the effects of the above-mentioned additives of the present invention are exhibited regardless of the amount of the oxide added, it is possible to add Ti to MgO.
Even when only O ₂ oxide is added, this is referred to as a plain material and is regarded as a part of the base material of the antimony-based compound.

【００２８】図３の実験結果にみられるようにＳｂ系の
化合物をＭｇＯに０．０５〜５％添加した場合、ＭｇＯ
の溶融は比較的低温で行われるので、たとえば二次再結
晶焼鈍でフォルステライト形成の最も行われやすい８０
０℃〜最高到達温度の平均昇温速度を比較的小さくした
方が、より早くフォルステライトの生成を促進させ、優
れた一次被膜を生成させやすいことになる。なおアンチ
モン（Ｓｂ）系の化合物とは前述のように当実験で用い
たＳｂ₂ （ＳＯ₄ ）₃ のみならずＳｂを含む他の化合物
を含む。このためアンチモン系の添加物をＭｇＯに添加
する場合は、二次再結晶焼鈍の８００℃〜最高到達温度
の平均昇温速度を最大８０℃／hrにする必要がある。初
期インヒビターＶＮから後期インヒビターＡｌＮへの移
行をよりスムーズに行い、さらなる高磁束密度を得るに
は５０℃／hr以下が好ましい。一方、０．１℃／hr未満
では工業的に成り立たないばかりか、本発明では後期イ
ンヒビターＡｌＮへの移行が遅れる。As shown in the experimental result of FIG. 3, when 0.05 to 5% of Sb-based compound was added to MgO, MgO
Is melted at a relatively low temperature, so that forsterite formation is most likely to occur by secondary recrystallization annealing.
If the average temperature increase rate from 0 ° C. to the highest temperature is set to be relatively small, the production of forsterite will be promoted more quickly and an excellent primary coating film will be produced more easily. The antimony (Sb) -based compound includes not only Sb ₂ (SO ₄ ) ₃ used in this experiment but other compounds containing Sb as described above. Therefore, when an antimony-based additive is added to MgO, it is necessary to set the average temperature rising rate of the secondary recrystallization annealing from 800 ° C to the highest reached temperature to a maximum of 80 ° C / hr. It is preferably 50 ° C./hr or less in order to make the transition from the early inhibitor VN to the late inhibitor AlN more smoothly and to obtain a higher magnetic flux density. On the other hand, if it is less than 0.1 ° C./hr, it is not industrially feasible, and in the present invention, the transition to the late-stage inhibitor AlN is delayed.

【００２９】一方、同じ低融点化合物でもボロン（Ｂ）
系の化合物をＭｇＯに０．０５〜５％添加した場合は、
ＭｇＯの溶融はＳｂ系の化合物よりも比較的高温で行わ
れるので、たとえば二次再結晶焼鈍の８００℃〜最高到
達温度の平均昇温速度を比較的大きくした方が、より早
くフォルステライトの生成を促進させる。このため、ボ
ロン（Ｂ）系の添加物をＭｇＯに添加する場合は二次再
結晶焼鈍の８００℃〜最高到達温度の平均昇温速度を最
低５℃／hrにする必要がある。しかしながら、４００℃
／hr超ではフォルステライトそのものの形成反応が安定
しない。On the other hand, even with the same low melting point compound, boron (B)
When 0.05 to 5% of the compound of the system is added to MgO,
Since the melting of MgO is performed at a relatively higher temperature than that of the Sb-based compound, for example, it is faster to generate forsterite by increasing the average temperature rising rate of the secondary recrystallization annealing from 800 ° C. to the highest reached temperature. Promote. Therefore, when the boron (B) -based additive is added to MgO, the average temperature rising rate of the secondary recrystallization annealing from 800 ° C to the highest reached temperature must be at least 5 ° C / hr. However, 400 ° C
If it exceeds / hr, the formation reaction of forsterite itself is not stable.

【００３０】本発明においてはＶＮからＡｌＮへの移行
が早すぎて高磁束密度が得られにくいので、最大５０℃
／hr未満が好ましい。このように珪素鋼板の特性に重要
な支配要因となる一次被膜は本発明により、その添加物
組成と製造方法との組み合わせにより、良好な状態にコ
ントロールすることが可能となった。In the present invention, since the transition from VN to AlN is too fast and it is difficult to obtain a high magnetic flux density, the maximum temperature is 50 ° C.
/ Hr is preferred. As described above, according to the present invention, the primary coating, which is an important controlling factor for the properties of the silicon steel sheet, can be controlled in a good state by the combination of the additive composition and the manufacturing method.

【００３１】さて、ここで珪素鋼板の製造方法に触れる
必要がある。本発明で極めて重要な点はＶとＮｂの挙動
であるがこれについては上述した。本発明の骨子はＳ
ｉ：１〜４％、Ａｌ：０．０１〜０．０５％、Ｖ：０．
０１〜０．１０％、Ｓ：０．０１％以下を含む鋼を溶製
し、１０００〜１２７０℃のスラブ均熱温度、８５０℃
以上の熱延仕上温度の熱間圧延、冷間圧延、一次再結晶
焼鈍および二次再結晶焼鈍を基本工程とする方向性電磁
鋼板の製造において、さらに溶鋼中および熱間圧延後か
ら二次再結晶焼鈍工程の二次再結晶焼鈍温度９５０℃に
到達する前のいずれかの工程で鋼に合計Ｎ：０．０１〜
０．０４％の窒素添加を行い、かつその合計のＮ量に対
してξ＝Ｎ％−（１４／５１）Ｖ％と定義したとき０．
００２％≦ξ≦０．０４％を満たし、かつ、η＝Ａｌ％
−（２７／１４）ξと定義したときＶ％−ηが０．００
５％≦Ｖ％−η≦０．０７％を満たすようにインヒビタ
ーを付与せしめ、かつ、一次再結晶焼鈍温度Ｔ₀ を７８
０℃＋１００（Ｖ％−η）≦Ｔ₀ ≦７８０℃＋５０００
（Ｖ％−η）で行い、かつ、上記の二次再結晶焼鈍前に
フォルステライトを主体とする一次被膜形成のために塗
布するマグネシアの中にアンチモン系の化合物を０．０
５〜５．０％添加するかあるいは全く何も意図的に添加
しない場合は二次再結晶焼鈍での８００℃〜最高到達温
度の平均昇温速度を毎時０．１〜８０℃とし、一方、マ
グネシアの中にボロン系、ストロンチウム・バリウム
系、炭・窒化物系、硫化物系、塩化物系の１種または２
種以上を合計０．０５〜５．０％添加する場合は二次再
結晶焼鈍での８００℃〜最高到達温度の平均昇温速度を
毎時５〜４００℃とすることを特徴とする。Now, it is necessary to touch on the method of manufacturing a silicon steel sheet. A very important point in the present invention is the behavior of V and Nb, which has been described above. The essence of the present invention is S
i: 1 to 4%, Al: 0.01 to 0.05%, V: 0.
Steel containing 01 to 0.10% and S: 0.01% or less is melted, slab soaking temperature of 1000 to 1270 ° C., 850 ° C.
In the production of grain-oriented electrical steel sheets with hot rolling at the above hot rolling finishing temperatures, cold rolling, primary recrystallization annealing and secondary recrystallization annealing as the basic steps, further during the molten steel and after the hot rolling, the secondary re-rolling In any of the steps before reaching the secondary recrystallization annealing temperature of 950 ° C. in the crystal annealing step, the total N: 0.01-
When adding 0.04% nitrogen and defining ξ = N% − (14/51) V% with respect to the total N amount,
002% ≦ ξ ≦ 0.04% and η = Al%
When defined as − (27/14) ξ, V% −η is 0.00
An inhibitor is added so as to satisfy 5% ≦ V% −η ≦ 0.07%, and the primary recrystallization annealing temperature T ₀ is 78.
0 ° C. + 100 (V% −η) ≦ T ₀ ≦ 780 ° C. + 5000
(V% -η) and before the secondary recrystallization annealing, magnesia applied for forming a primary film mainly composed of forsterite contains 0.0% of an antimony compound.
When 5 to 5.0% is added or nothing is intentionally added, the average rate of temperature increase from 800 ° C. to the maximum temperature reached in the secondary recrystallization annealing is 0.1 to 80 ° C./hour, while One or two of boron, strontium / barium, charcoal / nitride, sulfide, chloride in magnesia
In the case of adding 0.05 to 5.0% in total of the seeds or more, it is characterized in that the average temperature rising rate from 800 ° C. to the maximum reached temperature in the secondary recrystallization annealing is 5 to 400 ° C. per hour.

【００３２】必要に応じてさらにＮｂ：０．００８〜
０．０８％を溶鋼中に含み（このときは、式の中のＶ％
の項の代わりにＶ％＋（５１／９３）Ｎｂ％と置く）あ
るいはＶの代わりにＮｂ：０．００８〜０．０８％を溶
鋼中に含む（このときは、式の中のＶ％の項の代わりに
（５１／９３）Ｎｂ％と置く）ことを特徴としている。If necessary, Nb: 0.008-
0.08% in molten steel (at this time, V% in the formula
Vb + (51/93) Nb% instead of the term of) or Nb: 0.008 to 0.08% in the molten steel instead of V (at this time, V% of V Instead of the term, (51/93) Nb% is set).

【００３３】もちろん上記元素以外に、Ｍｎ，Ｓｅ，Ｓ
ｂ，Ｃｕ，Ｂ，Ｂｉ，Ｔｉ，Ｎｉ，Ｃｒ，Ｃｏ，Ｈｆ，
Ｃａ，Ｍｇ，Ｏ等の他の添加元素を付加的に添加させ、
磁気特性の向上をはかることは本発明の基本を変えるも
のではない。ただしこれらの元素は本発明の本質を損わ
ないためにはその合計で最大１％である必要がある。ま
た、特に本発明鋼の高磁束密度を補佐する元素として、
Ｐは有効であり、０．００５％以上からその効果が認め
られた。０．１％以下ならば鋼の脆性も引き起こさずむ
しろ添加する方が好ましい。Of course, in addition to the above elements, Mn, Se, S
b, Cu, B, Bi, Ti, Ni, Cr, Co, Hf,
By adding other additive elements such as Ca, Mg and O,
Improving the magnetic properties does not change the basics of the invention. However, in order not to impair the essence of the present invention, the total of these elements must be 1% at the maximum. Further, particularly as an element to assist the high magnetic flux density of the steel of the present invention,
P is effective, and the effect was recognized from 0.005% or more. If it is 0.1% or less, brittleness of steel is not caused, and it is more preferable to add it.

【００３４】また、二次再結晶粒の粗大化を防止し。鉄
損の低減にＳｎを添加することは有効である。Ｓｎの上
限は０．３％であり、これ以上では被膜形成が十分行わ
れず、一方、鉄損低減効果は０．０２％以上から認めら
れる。Ｃは通常０．１％以下程度存在し、磁性向上にも
間接的に寄与し、本発明では０．０３〜０．０７％程度
が適当だが、必ずしも本発明の高磁束密度で必須という
わけではない。It also prevents coarsening of secondary recrystallized grains. It is effective to add Sn to reduce iron loss. The upper limit of Sn is 0.3%, and if it is more than this, film formation is not sufficiently performed, while the iron loss reducing effect is recognized from 0.02% or more. C is usually present in an amount of about 0.1% or less and indirectly contributes to the improvement of magnetism. In the present invention, about 0.03 to 0.07% is suitable, but it is not always essential for the high magnetic flux density of the present invention. Absent.

【００３５】Ｎは珪素鋼板製造工程における冷延後の一
次焼鈍中または直後に鋼板に直接窒化反応を介して鋼に
Ｎを強制的に添加せしめる等の方法により、溶鋼中のＮ
と併せ二次再結晶焼鈍の９５０℃に到達する前にＮを
０．０１〜０．０４％が鋼に含まれることを特徴とす
る。０．０１％未満ではＶＮ，ＡｌＮ，ＮｂＮあるいは
付帯的にＳｉ₃ Ｎ₄ 等のインヒビターが十分できず、高
磁束密度が得られず、一方、０．０４％超ではフォルス
テライト被膜が良好にできない。N is contained in the molten steel by a method such as forcibly adding N to the steel through a direct nitriding reaction on the steel during or immediately after the primary annealing after cold rolling in the silicon steel sheet manufacturing process.
In addition, 0.01 to 0.04% of N is contained in the steel before reaching 950 ° C. in the secondary recrystallization annealing. If it is less than 0.01%, sufficient inhibitors such as VN, AlN, NbN or incidentally Si ₃ N ₄ cannot be obtained, and high magnetic flux density cannot be obtained. On the other hand, if it exceeds 0.04%, the forsterite coating cannot be well formed. .

【００３６】なお、二次再結晶焼鈍の９５０℃はＶＮ等
のインヒビターがほぼ十分に生成されている温度であ
り、これより高い温度ではじめてＮが十分供給されても
本発明の高磁束密度は得にくい。なお、溶鋼中には０．
００３〜０．０１２％程度含まれることが本発明では最
適である。Ｓｉは本発明においては上記のようにフォル
ステライト形成のためと鉄損低減のために最低１％は必
要である。一方、４％を超えると飽和磁束密度が低下し
高磁束密度鋼には適さない。The temperature of 950 ° C. in the secondary recrystallization annealing is the temperature at which the inhibitors such as VN are almost sufficiently formed, and even if N is sufficiently supplied at a temperature higher than this temperature, the high magnetic flux density of the present invention is high. Hard to get. It should be noted that, in the molten steel, 0.
In the present invention, the optimum content is about 003 to 0.012%. In the present invention, Si is required to be at least 1% for forming forsterite and reducing iron loss as described above. On the other hand, if it exceeds 4%, the saturation magnetic flux density is lowered and it is not suitable for high magnetic flux density steel.

【００３７】ＡｌはＡｌＮインヒビター形成に有効であ
り、最低０．０１％は必要である。しかし０．０５％を
超えるとＶ等との関係で前述の理由で高磁束密度は得ら
れないばかりか、ＡｌＮ等の析出物の生成促進をかえっ
て阻害し、いわゆるインヒビター不足となって細粒とな
りやすい。この他の元素は本発明では以下に制約するこ
とが好ましい。Al is effective in forming an AlN inhibitor, and a minimum amount of 0.01% is necessary. However, if it exceeds 0.05%, not only a high magnetic flux density cannot be obtained due to the relationship with V and the like for the above-mentioned reason, but also the promotion of the formation of precipitates such as AlN is rather hindered and so-called inhibitor deficiency occurs, resulting in fine grains. Cheap. In the present invention, the other elements are preferably restricted as follows.

【００３８】ＳはＭｎと反応してＭｎＳインヒビターを
形成するが本発明では必須ではなくむしろ熱延板の耳割
れ防止のために０．０１％以下にする必要がある。Ｍｎ
は必須ではないが、Ｓと化合し、耳割れ防止にも０．０
５％以上入れることは有効であるが、０．２０％超では
磁性劣化をもたらす。Ｏは鋼溶製後に０．０３％以下で
あればＡｌ₂ Ｏ₃ を多量に作りすぎず清浄度的に好まし
い。S reacts with Mn to form an MnS inhibitor, but it is not essential in the present invention, and is preferably 0.01% or less in order to prevent the edge cracking of the hot rolled sheet. Mn
Is not essential, but it combines with S to prevent ear cracking at 0.0
It is effective to add 5% or more, but if it exceeds 0.20%, magnetic deterioration is caused. If O is 0.03% or less after the steel is melted, a large amount of Al ₂ O ₃ is not excessively produced, which is preferable in terms of cleanliness.

【００３９】次に化学成分以外の本発明の製造方法につ
いて述べる。鋼を転炉または電気炉等で出鋼し、必要に
応じて精錬工程を加えて成分調整を行った溶鋼を連続鋳
造法、造塊分塊圧延法あるいは熱延工程省略のための薄
スラブ連続鋳造法等により、厚さ３０〜４００mm（薄ス
ラブ連続鋳造法では５０mm以下）のスラブとする。ここ
で３０mmは生産性の下限であり、４００mmは中心偏析で
Ａｌ₂ Ｏ₃ 等の分布が異常になることを防ぐための上限
である。また薄スラブ連続鋳造法での５０mmは冷速が小
さくなって粗大粒が出てくることを抑制するための上限
である。Next, the production method of the present invention other than the chemical components will be described. Continuous casting method, ingot-agglomeration and rolling method, or thin slab continuous method for omitting hot rolling step, in which steel is tapped in a converter or electric furnace, and a refining step is added as necessary to adjust the composition. A slab having a thickness of 30 to 400 mm (50 mm or less in the thin slab continuous casting method) is formed by a casting method or the like. Here, 30 mm is the lower limit of productivity, and 400 mm is the upper limit for preventing abnormal distribution of Al ₂ O ₃ etc. due to center segregation. Further, 50 mm in the thin slab continuous casting method is the upper limit for suppressing the generation of coarse particles due to the low cooling rate.

【００４０】該スラブをガス加熱、電気利用加熱等によ
り１０００〜１２７０℃に再加熱を行い、引き続き熱間
圧延を行って厚さ１０mm以下のホットコイルとする。こ
こで１０００℃はＡｌＮがスラブでも十分溶解する下限
であり、１２７０℃はスラブおよび熱延後の肌荒れと組
織粗大化による線条細粒等の磁性劣化を防止するための
上限である。また１０mmは適正な析出物を生成する冷速
を得る上限である。なお、薄スラブ連続鋳造法では直接
コイル状にすることも可能であり、そのためには１０mm
以下が好ましい。The slab is reheated to 1000 to 1270 ° C. by gas heating, electric heating, etc., and then hot rolled to obtain a hot coil having a thickness of 10 mm or less. Here, 1000 ° C. is a lower limit at which AlN is sufficiently dissolved even in a slab, and 1270 ° C. is an upper limit for preventing magnetic deterioration such as filament fine grains due to roughening of the surface of the slab and hot rolling and coarsening of the structure. Further, 10 mm is an upper limit for obtaining a cold speed at which an appropriate precipitate is formed. In the thin slab continuous casting method, it is possible to directly form a coil, for which 10 mm
The following are preferred.

【００４１】さて通常のスラブからの熱延において、仕
上温度は８５０℃以上にする必要がある。これ未満の温
度ではＡｌＮ等が熱延板中に粗大析出しやすく後の一次
焼鈍組織がコントロールしにくくなり、結果的に高磁束
密度が得られない。さらに巻取り温度は本発明では必ず
しも本質的ではないものの、６８０℃以下にすることで
ＡｌＮの粗大析出を防ぎ、高磁束密度に良い。なお、連
続（または連連続）熱延法と称し、粗圧延後、中間製品
の厚手の熱延板を一時的にコイル状に巻いたりして、保
熱して、次々と該コイルを接合し、さらに連続的に熱延
する方法は、とりわけ長手方向の組織、成分均一化とそ
の保熱中の析出物コントロールによる後工程の熱延板焼
鈍の一部または全部の代替の効果が期待され、本発明鋼
にも有効である。In hot rolling from a normal slab, the finishing temperature must be 850 ° C or higher. If the temperature is lower than this, AlN or the like is likely to be coarsely precipitated in the hot-rolled sheet, which makes it difficult to control the subsequent primary annealing structure, and as a result, high magnetic flux density cannot be obtained. Further, although the winding temperature is not always essential in the present invention, setting it to 680 ° C. or lower prevents coarse precipitation of AlN and is good for high magnetic flux density. Incidentally, referred to as continuous (or continuous continuous) hot rolling method, after rough rolling, by temporarily winding a thick hot rolled sheet of an intermediate product into a coil shape, heat retention, and joining the coils one after another, Further, the method of continuous hot rolling is expected to have the effect of substituting a part or all of the annealing of the hot rolled sheet in the subsequent step by controlling the precipitate in the longitudinal direction, the homogenization of the composition, the uniformization of the components, and the like. It is also effective for steel.

【００４２】このように作ったホットコイルを再び８０
０〜１２５０℃で焼鈍（熱延板焼鈍）し、長手方向の磁
性の均一化とさらなる向上をはかることもしばしば行わ
れる。ここで８００℃はコイル長手方向の組織均一化の
下限であり、１２５０℃はＡｌＮ粗大化防止による高磁
束密度化のための上限である。The hot coil made in this way is used again for 80
Annealing (hot-rolled sheet annealing) at 0 to 1250 ° C. is often performed to make the longitudinal magnetism uniform and further improve. Here, 800 ° C. is the lower limit for uniforming the structure in the coil longitudinal direction, and 1250 ° C. is the upper limit for increasing the magnetic flux density by preventing AlN coarsening.

【００４３】かかる処理工程の後、ホットコイルを直接
またはバッチ的に酸洗後冷間圧延を行う。冷間圧延は圧
下率６０〜９５％で行うが、６０％は本発明で再結晶可
能な限界であり、好ましくは７０％以上が一次焼鈍で
｛１１１｝〈１１２〉方位粒を多くして、二次再結晶焼
鈍時のＧｏｓｓ方位粒の生成を促進させる下限である。
さらに、よりＧｏｓｓ方位を二次再結晶で先鋭化させる
には１回冷延法では８５％以上が好ましい。After this treatment step, the hot coil is directly or batch-pickled and then cold-rolled. Cold rolling is carried out at a rolling reduction of 60 to 95%, 60% being the limit of recrystallization in the present invention, preferably 70% or more by primary annealing and increasing {111} <112> oriented grains, This is the lower limit for promoting the generation of Goss-oriented grains during secondary recrystallization annealing.
Further, in order to further sharpen the Goss orientation by secondary recrystallization, it is preferably 85% or more in the single cold rolling method.

【００４４】一方９５％超では二次再結晶焼鈍で首振り
Ｇｏｓｓ粒と称するＧｏｓｓ方位粒が板面内回転した磁
気特性に好ましくない粒が生成される。以上はいわゆる
１回冷延法で製造する場合だが、２回冷延法と称して冷
延−焼鈍−冷延を行う場合は、１回目の圧下率は１０〜
８０％、２回目の圧下率は５０〜９５％となる。ここで
１０％は再結晶に必要な最低圧下率、８０％と９５％は
それぞれ二次再結晶時に適正なＧｏｓｓ方位粒を生成さ
せるための上限圧下率、また５０％は２回冷延法におい
ては一次焼鈍時の｛１１１｝〈１１２〉方位粒を適正に
残す下限圧下率である。On the other hand, if it exceeds 95%, secondary recrystallization annealing causes Goss-oriented grains, which are called swinging Goss grains, to rotate in the plane of the plate to produce grains unfavorable to the magnetic properties. The above is the case of manufacturing by the so-called one-time cold rolling method, but in the case of performing cold rolling-annealing-cold rolling by calling the two-time cold rolling method, the first reduction rate is 10 to 10.
The rolling reduction of 80% for the second time is 50 to 95%. Here, 10% is the minimum reduction ratio necessary for recrystallization, 80% and 95% are the upper limit reduction ratios for producing proper Goss-oriented grains at the time of secondary recrystallization, and 50% in the double cold rolling method. Is the lower limit of the reduction rate in which the {111} <112> oriented grains are appropriately left during the primary annealing.

【００４５】なお、通称パス間エージングと称し、冷間
圧延の途中で鋼板を適当な方法で１００〜４００℃の範
囲で、加熱または冷間圧延の加工熱を利用し保熱するこ
とも磁気特性の向上に有効である。１００℃未満ではエ
ージングの効果がなく、一方、４００℃超では転位が回
復してしまう。It is also called "pass-aging", and it is also possible to heat-treat the steel sheet by a suitable method during the cold rolling in the range of 100 to 400 ° C by utilizing the working heat of heating or cold rolling. Is effective in improving. If it is less than 100 ° C, the effect of aging is not obtained, while if it exceeds 400 ° C, dislocations are recovered.

【００４６】しかる後、１回冷延法でも２回冷延法でも
一次焼鈍を行うわけであるが、この焼鈍で脱炭を行うこ
とは有効である。これは、前述のようにＣは二次再結晶
粒のＧｏｓｓ粒の核生成に有効であるが、不純物として
残ると鉄損の劣化を招くためである。なお、予め鋼の溶
製時にＣを下げておくと脱炭工程が短縮化されるばかり
か｛１１１｝〈１１２〉方位粒も増やすので、その鋼の
要求特性によって本発明でも好ましい場合がある。な
お、この脱炭焼鈍工程で適正な露点を設定することで後
の一次被膜生成に必要な酸化層の確保が行われる。Thereafter, the primary annealing is carried out by either the single cold rolling method or the double cold rolling method, and it is effective to carry out decarburization by this annealing. This is because C is effective for nucleating the Gosss grains of the secondary recrystallized grains as described above, but if it remains as an impurity, the iron loss is deteriorated. It should be noted that if C is lowered in advance during melting of steel, not only the decarburization step is shortened but also {111} <112> oriented grains are increased, so that the present invention may be preferable depending on the required characteristics of the steel. By setting an appropriate dew point in this decarburization annealing step, the oxide layer necessary for the subsequent formation of the primary coating can be secured.

【００４７】一次焼鈍温度は本発明鋼では重要である。
その制約の条件と理由は前述した。さらに、ＡｌＮやＶ
Ｎ，ＮｂＮあるいは付随的なＳｉ₃ Ｎ₄ インヒビターの
Ｎの一部をこの一次焼鈍時または直後に窒化法等で強制
添加することを窒化法の一つとしてその特徴とする本発
明においては、上記の一次焼鈍中または直後に引き続き
アンモニア（ＮＨ₃ ）等で窒化法により窒化することが
しばしば行われる。この場合の窒化法の温度は６００〜
９５０℃が好ましい。ここで６００℃は窒化反応を起こ
す下限であり、一方９５０℃は粗大粒発生を抑える上限
である。The primary annealing temperature is important in the steel of the present invention.
The conditions and reasons for the restrictions have been described above. In addition, AlN and V
In the present invention, one of the nitriding methods is characterized in that N, NbN or a part of N of an accompanying Si ₃ N ₄ inhibitor is forcibly added by a nitriding method during or immediately after the primary annealing. During or immediately after the primary annealing, nitriding is often performed subsequently with ammonia (NH ₃ ) or the like by a nitriding method. The temperature of the nitriding method in this case is 600 to
950 ° C is preferred. Here, 600 ° C. is the lower limit for causing the nitriding reaction, while 950 ° C. is the upper limit for suppressing the generation of coarse particles.

【００４８】本発明においては窒化は一次再結晶焼鈍直
後に行うのが好ましいが、これは前述のように工業的に
は同じ炉内の後面に仕切りを設けて雰囲気を必要に応じ
て多少変えて、ＮＨ₃ ガスを流すか、近接した設備で行
うため一次再結晶と平行して窒化されることがしばしば
行われる。なお、窒化の一部を二次再結晶焼鈍中に行う
ことも９５０℃以下であれば本発明の主旨を損わない。
一次焼鈍あるいは上記窒化法を併用したコイルをその
後、酸化マグネシウム（ＭｇＯを主成分とする、以下Ｍ
ｇＯと呼ぶ）パウダーを水または水を主成分とする水溶
液に溶かしスラリー状にして鋼板に塗布する。In the present invention, the nitriding is preferably performed immediately after the primary recrystallization annealing, but this is industrially provided with a partition on the rear surface of the same furnace and the atmosphere is slightly changed as necessary as described above. , NH ₃ gas is flown or is performed in a nearby facility, so that nitriding is often performed in parallel with primary recrystallization. It should be noted that part of the nitriding may be performed during the secondary recrystallization annealing as long as it is 950 ° C. or lower without impairing the gist of the present invention.
The coil obtained by combining the primary annealing or the above nitriding method is then subjected to magnesium oxide (MgO as a main component, hereinafter referred to as M
The powder is called gO) is dissolved in water or an aqueous solution containing water as a main component to form a slurry, which is applied to a steel sheet.

【００４９】この際、後の二次再結晶焼鈍時にＭｇＯパ
ウダーの溶融を容易にさせ、フォルステライト生成反応
を促進させる目的で、適当な化合物を微量添加すること
も行われる。ＴｉＯ₂ を添加する場合は１〜１５％が好
ましいが、ここで１％はフォルステライト反応促進効果
を発揮する下限であり、１５％超ではＭｇＯが少なくな
ってかえってフォルステライト反応が進まない。Ｓｂ₂
（ＳＯ₄ ）₃ 等のアンチモン系の化合物はＭｇＯを比較
的低温で溶融させるのに効果があり、添加を行う場合は
０．０５〜５％が好ましい。ここで、０．０５％は上記
低温溶融を起こす下限であり、一方、５％を超える場合
は多すぎてＭｇＯのフォルステライトの本来の反応を不
活性化する。At this time, a trace amount of an appropriate compound may be added for the purpose of facilitating the melting of the MgO powder during the subsequent secondary recrystallization annealing and accelerating the forsterite formation reaction. When TiO ₂ is added, it is preferably 1 to 15%, but 1% is the lower limit at which the effect of promoting the forsterite reaction is exhibited, and if it exceeds 15%, the amount of MgO decreases and the forsterite reaction does not proceed. Sb ₂
An antimony-based compound such as (SO ₄ ) ₃ is effective in melting MgO at a relatively low temperature, and when added, 0.05 to 5% is preferable. Here, 0.05% is the lower limit for causing the above-mentioned low-temperature melting, while if it exceeds 5%, it is too much to inactivate the original reaction of MgO forsterite.

【００５０】Ｎａ₂ Ｂ₄ Ｏ₇ 等のボロン系の化合物およ
びそれと同様の作用を持つストロンチウム・バリウム
系、炭・窒化物系、硫化物系、塩化物系の化合物はアン
チモン系よりは比較的高温でＭｇＯを溶融させるのに効
果があり、添加する場合は０．０５〜５％が好ましい。
ここで、０．０５％は上記の効果を発揮する下限であ
り、一方５％超ではやはりＭｇＯのフォルステライトの
本来の反応を不活性化するので好ましくない。Boron-based compounds such as Na ₂ B ₄ O ₇ and strontium / barium-based, carbon / nitride-based, sulfide- and chloride-based compounds having a similar action to those of the compounds have a relatively higher temperature than antimony-based compounds. Is effective in melting MgO, and when added, 0.05 to 5% is preferable.
Here, 0.05% is the lower limit for exhibiting the above-mentioned effect, while if it exceeds 5%, the original reaction of MgO forsterite is inactivated, which is not preferable.

【００５１】なおこれらの化合物は互いに複合して添加
することも可能である。ただしアンチモン系の低温溶融
型とボロン系（非アンチモン系）、他の比較的高温溶融
型の化合物を混ぜて使用するときは、その効果は高温溶
融型に近いことになるが、本発明の主旨と矛盾するもの
ではなく、その場合は本発明のボロン系の高温溶融型の
昇温速度をとることが好ましい。It should be noted that these compounds can be added in combination with each other. However, when an antimony low-temperature melting type compound, a boron-type (non-antimony type) compound, and other relatively high-temperature melting type compound are mixed and used, the effect is close to that of the high-temperature melting type compound. In that case, it is preferable to use the boron-based high temperature melting type temperature rising rate of the present invention.

【００５２】なお、ここで添加する化合物の％はＭｇＯ
の重量を１００％としたときの重量比を％で示してあ
る。二次再結晶焼鈍は最高到達温度を１１００〜１３０
０℃で行うのが好ましい。１１００℃はＡｌＮを使う二
次再結晶がほぼ十分に行われ、かつ、諸元素の純化が行
われる下限の温度であり、一方１３００℃超では結晶粒
が粗大化しすぎて鉄損の劣化を招く。なお、前述のよう
に、この二次再結晶焼鈍中の９５０℃までの比較的前段
階で雰囲気や固体、液体の鋼板との反応等によりＮを追
加添加する窒化法が行われることもあるし、焼鈍雰囲気
から不可避的に窒素が侵入することもある。この場合も
本発明では９５０℃以下での鋼中の合計のＮ量が高磁束
密度に作用することはいうまでもない。さて、この二次
再結晶焼鈍の昇温速度はとりわけ本発明では重要である
がその理由は前述した。The percentage of the compound added here is MgO.
The weight ratio is shown in% when the weight of is 100%. Secondary recrystallization annealing has a maximum temperature of 1100 to 130
It is preferably carried out at 0 ° C. 1100 ° C is a lower limit temperature at which secondary recrystallization using AlN is almost sufficiently performed and purification of various elements is performed. On the other hand, if it exceeds 1300 ° C, crystal grains are excessively coarsened and iron loss is deteriorated. . Note that, as described above, the nitriding method in which N is additionally added may be performed at a relatively prior stage up to 950 ° C. during the secondary recrystallization annealing due to reaction with the atmosphere, solid, or liquid steel sheet. However, nitrogen may inevitably invade from the annealing atmosphere. Even in this case, it goes without saying that in the present invention, the total amount of N in steel at 950 ° C. or lower acts on the high magnetic flux density. Now, the temperature rising rate of the secondary recrystallization annealing is particularly important in the present invention, and the reason is as described above.

【００５３】以上が本発明の珪素鋼板の製造方法での重
要な部分であるが、工業的にはさらに絶縁特性や張力付
与による鉄損等の磁気特性を向上させる目的で鋼板に有
機質や無機質や半有機質による二次被膜の生成や、さら
にその前後いずれかに歯車法やプレス法等による溝付け
等の機械的方法あるいは化学的方法により溝付けする方
法、またはレーザー照射等のエネルギー付与による非接
触型の不均質部付与の方法等による磁区制御法を行うこ
とは、本発明の高磁束密度鋼の優れた特長を活かすのに
最適である。The above is an important part of the method for producing a silicon steel sheet according to the present invention. Industrially, the steel sheet may be made of an organic or inorganic material for the purpose of improving magnetic properties such as insulation loss and iron loss due to tension application. Non-contact by semi-organic secondary film formation, and mechanical or chemical grooving either before or after it by a gear method or a pressing method, or by applying energy such as laser irradiation. Performing a magnetic domain control method such as a method of imparting a non-uniform portion of the die is optimal for utilizing the excellent features of the high magnetic flux density steel of the present invention.

【００５４】[0054]

【実施例】表１に示すような化学成分の鋼を転炉で溶製
し、表１に示すような条件で製造した。熱延板焼鈍の条
件（１）とは９００℃×２分均熱後空冷し、７５０℃か
ら８０℃に湯冷、条件（２）とは１１２０℃×３０秒均
熱後炉冷し、９００℃から空冷、７５０℃から８０℃に
湯冷したことを示す。また冷間圧延時のパス間エージン
グをＢ１〜Ｂ５、Ｆ１〜Ｆ４以外は全て行ったがその条
件は２５０℃である。なお、ここで本発明にとりわけ重
要な一次再結晶焼鈍に引き続く窒化は同一炉内に仕切り
を設けた炉中内部分で同一ガス組成で雰囲気をドライに
し、ＮＨ₃ ガスを一定量流して行ったものである。EXAMPLES Steels having chemical compositions shown in Table 1 were melted in a converter and manufactured under the conditions shown in Table 1. Condition (1) of hot-rolled sheet annealing is soaked at 900 ° C. for 2 minutes and then air-cooled, and hot-water cooled from 750 ° C. to 80 ° C. Condition (2) is soaked at 1120 ° C. for 30 seconds and furnace-cooled, 900 The figure shows that it was cooled by air from ℃ and cooled by hot water from 750 ℃ to 80 ℃. In addition, aging between passes during cold rolling was performed except for B1 to B5 and F1 to F4, but the condition was 250 ° C. Here, the nitriding subsequent to the primary recrystallization annealing, which is particularly important in the present invention, was performed by making the atmosphere dry with the same gas composition and flowing a certain amount of NH ₃ gas in the inside of the furnace where the partition was provided in the same furnace. It is a thing.

【００５５】表１で溶鋼以外の窒化法有としたものはＢ
１〜Ｂ５以外は全てこの方法で行ったが、Ｂ１〜Ｂ５は
二次再結晶焼鈍の７５０〜９００℃の温度域で窒化し
た。この表での二次再結晶焼鈍の９５０℃までのＮ％と
は熱間圧延前のスラブ（通常、溶鋼の値と等しい）の窒
素量とこれらの窒化法によって加わった窒素量の合計を
示している。なお、表１のＮｂを添加したＣ１〜Ｃ４、
Ｄ１〜Ｄ５、Ｊ１についてはξやＶ％−ηの中に表され
るＶ％の代わりにＶ％＋（５１／９３）Ｎｂ％（Ｖを添
加しない鋼では（５１／９３）Ｎｂ％）を使用した。In Table 1, those having a nitriding method other than molten steel are B
All the processes except 1 to B5 were performed by this method, but B1 to B5 were nitrided in the temperature range of 750 to 900 ° C. of the secondary recrystallization annealing. The N% up to 950 ° C. in the secondary recrystallization annealing in this table indicates the sum of the nitrogen content of the slab before hot rolling (usually equal to the value of molten steel) and the nitrogen content added by these nitriding methods. ing. In addition, C1 to C4 to which Nb in Table 1 is added,
For D1 to D5 and J1, V% + (51/93) Nb% ((51/93) Nb% in steel without V added) is used instead of V% represented in ξ or V% −η. used.

【００５６】さらに、この鋼板にパウダーを塗布した
が、パウダーは水に溶解させスラリー状にして塗布後、
３５０℃で乾燥させた。パウダーの種類で、プレインと
はＭｇＯ＋ＴｉＯ₂ （５％）の組成であり、Ｓｂ系とは
ＭｇＯ＋ＴｉＯ₂ （５％）＋Ｓｂ₂ （ＳＯ₄ ）₃ （０．
２％）のことであり、また、Ｂ系（１）とはＭｇＯ＋Ｔ
ｉＯ₂ （５％）＋Ｎａ₂ Ｂ₄ Ｏ₇ （０．３％）、Ｂ系
（２）とはＭｇＯ＋Ｎａ₂Ｂ₄ Ｏ₇ （０．１％）＋Ｓｒ
ＣＯ₃ （０．０８％）＋ＢａＣｌ₂ （０．５％）＋Ｂａ
（ＯＨ）₂ （０．１％）＋Ｓｂ₂ （ＳＯ₄ ）₃ （０．２
％）、Ｂ系（３）とはＭｇＯ＋ＭｇＳＯ₄ （４．０％）
＋ＦｅＳＯ₄ （０．１％）＋ＭｇＣｌ₂ （０．４％）の
ことを示す。また、Ｓ０はＭｇＯ＋ＴｉＯ₂ （５％）＋
Ｓｂ₂ （ＳＯ₄ ）₃ （０．０３％）、Ｓ５はＭｇＯ＋Ｔ
ｉＯ₂ （３％）＋Ｓｂ₂ （ＳＯ₄ ）₃（６％）を示し、
一方、Ｂ０はＭｇＯ＋ＴｉＯ₂ （５％）＋Ｎａ₂ Ｂ₄ Ｏ
₇ （０．０２％）、Ｂ５はＭｇＯ＋ＴｉＯ₂ （５％）＋
Ｎａ₂ Ｂ₄ Ｏ₇ （７％）のことを示す。ここで、％はＭ
ｇＯの重量を１００％としたときの重量比率である。Further, powder was applied to this steel sheet. The powder was dissolved in water to form a slurry, and after application,
It was dried at 350 ° C. A type of powder, the plain is a composition of MgO + TiO ₂ (5%), and the Sb type is MgO + TiO ₂ (5%) + Sb ₂ (SO ₄ ) ₃ (0.
2%), and B type (1) means MgO + T
iO ₂ (5%) + Na ₂ B ₄ O ₇ (0.3%), B system (2) means MgO + Na ₂ B ₄ O ₇ (0.1%) + Sr
CO ₃ (0.08%) + BaCl ₂ (0.5%) + Ba
(OH) ₂ (0.1%) + Sb ₂ (SO ₄ ) ₃ (0.2
%) And B type (3) means MgO + MgSO ₄ (4.0%)
+ FeSO ₄ (0.1%) + MgCl ₂ (0.4%). In addition, S0 is MgO + TiO ₂ (5%) +
Sb ₂ (SO ₄ ) ₃ (0.03%), S5 is MgO + T
iO ₂ (3%) + Sb ₂ (SO ₄ ) ₃ (6%),
On the other hand, B0 is MgO + TiO ₂ (5%) + Na ₂ B ₄ O
₇ (0.02%), B5 is MgO + TiO ₂ (5%) +
It means Na ₂ B ₄ O ₇ (7%). Where% is M
It is a weight ratio when the weight of gO is 100%.

【００５７】しかる後に、８００℃〜最高到達温度の平
均昇温速度を種々変えて二次再結晶焼鈍を行った。さら
に水洗後、リン酸系の絶縁被膜（二次被膜）（但し、Ｅ
１〜Ｅ４のみはゾルゲル法＋リン酸系の絶縁被膜の組み
合わせ、Ｆ１〜Ｆ４のみはゾルゲル法の絶縁被膜）を加
熱塗布した後、板取りし、歪取り焼鈍８５０℃×４時間
（Ｎ₂ ９０−Ｈ₂ １０，Ｄｒｙ）を行い、一次被膜およ
びマクロ外観検査、磁気測定、被膜密着性試験等を行っ
た。表１にその結果を示す。なお、一部については歪取
り焼鈍前後にさらに磁区制御を行ったが、ここで（１）
は機械法（歯車）、（２）はレーザー法、（３）は化学
的エッチング法を使用したことを示す。After that, secondary recrystallization annealing was carried out by changing the average heating rate from 800 ° C. to the maximum reached temperature variously. After further washing with water, phosphoric acid-based insulating film (secondary film) (however, E
1 to E4 only is a combination of a sol-gel method + phosphoric acid type insulating coating, and F1 to F4 is only a sol-gel method insulating coating) is heat-coated, then plate-cut and strain relief annealing 850 ° C. × 4 hours (N ₂ 90 -H ₂ 10, Dry) performed, primary coatings and macro visual inspection, magnetic measurements, the coating adhesion test, etc. conducted. The results are shown in Table 1. Some of the magnetic domains were further controlled before and after the strain relief annealing.
Indicates that the mechanical method (gear) was used, (2) the laser method, and (3) the chemical etching method.

【００５８】ここで、被膜外観検査は、○：スケール、
シモフリ欠陥なし、△：若干のシモフリ欠陥あり、×：
スケール、シモフリが多く被膜が十分できていない、こ
とを示す。ここでスケールとは一次被膜がある程度広く
はがれた状態を示しており、シモフリとは点状のはがれ
欠陥である。被膜の密着性試験は直径２０mmの円柱に鋼
板を巻き付けるような曲げ試験において、その判定を、
○：被膜のクラックなし、△：被膜の微細クラックあ
り、×：ほぼ全幅にクラック、で評価した。また、マク
ロ外観検査は、○：十分な二次再結晶ができている、
△：部分的に細粒が認められる、×：全面に細粒が認め
られる、ことを示す。Here, the visual inspection of the film is as follows: ○: scale,
No shimou defect, △: Some shimmi defect, ×:
It shows that there are many scales and shimofuri and the film is not sufficiently formed. Here, the scale means a state in which the primary coating is widely peeled to some extent, and the shimofuri is a point-like peeling defect. The adhesion test of the coating is determined by a bending test in which a steel plate is wrapped around a cylinder having a diameter of 20 mm,
◯: No cracks in the coating, Δ: fine cracks in the coating, ×: cracks almost in the entire width. In addition, the macro visual inspection is ◯: Sufficient secondary recrystallization,
Δ: Fine particles are partially observed, ×: Fine particles are observed on the entire surface.

【００５９】磁気測定は６０×３００（圧延方向）mmの
単板のＳＳＴ試験法で測定し、Ｂ₈（８００A/m の磁束
密度、単位はテスラ）およびＷ_17/50 （５０Hzで１．７
テスラのときの鉄損、単位はワット／kg）、および磁歪
を測定した。磁歪は６０×３００（長手方向）mmの試験
片をドップラー式の磁歪測定器で５０Hz、磁束密度１．
７Ｔで行い、磁歪カーブの最大値から最小値を引いた値
で示した。なお、Ｂ１〜Ｂ５のみは試験片長手方向に
０．３kg／mm² の圧縮力を加えて磁歪測定した。なお、
磁区制御材の磁気特性については全て磁区制御後の値を
示した。The magnetic measurement was carried out by the SST test method of a single plate of 60 × 300 (rolling direction) mm, B ₈ (magnetic flux density of 800 A / m, unit: Tesla) and W _17/50 (1.7 at 50 Hz).
The iron loss at Tesla, the unit is watt / kg, and the magnetostriction were measured. Magnetostriction was 60 × 300 (longitudinal direction) mm and a Doppler-type magnetostriction measuring instrument was used to measure 50 Hz and magnetic flux density was 1.
The value was obtained by subtracting the minimum value from the maximum value of the magnetostrictive curve. Only B1 to B5 were subjected to magnetostriction measurement by applying a compressive force of 0.3 kg / mm ^{2 in} the longitudinal direction of the test piece. In addition,
The magnetic properties of the magnetic domain control materials are all the values after magnetic domain control.

【００６０】[0060]

【表１】 [Table 1]

【００６１】[0061]

【表２】 [Table 2]

【００６２】[0062]

【表３】 [Table 3]

【００６３】[0063]

【表４】 [Table 4]

【００６４】[0064]

【表５】 [Table 5]

【００６５】[0065]

【表６】 [Table 6]

【００６６】[0066]

【表７】 [Table 7]

【００６７】[0067]

【表８】 [Table 8]

【００６８】[0068]

【表９】 [Table 9]

【００６９】[0069]

【表１０】 [Table 10]

【００７０】[0070]

【表１１】 [Table 11]

【００７１】[0071]

【表１２】 [Table 12]

【００７２】[0072]

【表１３】 [Table 13]

【００７３】[0073]

【表１４】 [Table 14]

【００７４】[0074]

【表１５】 [Table 15]

【００７５】[0075]

【表１６】 [Table 16]

【００７６】[0076]

【発明の効果】本発明鋼は熱延条件やＶ，Ｎｂ，Ａｌ，
Ｎの複雑なバランスとそれをベースにした一次再結晶焼
鈍温度の最適な温度範囲およびマグネシアパウダーへの
添加物と、二次再結晶焼鈍の８００℃〜最高到達温度の
平均昇温速度の諸因子の中で、熱延耳割れがないか非常
に小さく、かつ極めて高い磁束密度と良好な一次被膜の
双方が組み合わさることによる低鉄損、低磁歪を有する
ことを示された。とりわけ低磁歪や磁区制御材での鉄損
低減効果が顕著である。INDUSTRIAL APPLICABILITY The steel according to the present invention has hot rolling conditions, V, Nb, Al,
Optimum temperature range of primary recrystallization annealing temperature based on the complicated balance of N and additives to magnesia powder, and factors of average heating rate of secondary recrystallization annealing from 800 ° C to the maximum reached temperature Among them, it was shown that there is little or no hot-rolled ear crack, and that it has low iron loss and low magnetostriction due to the combination of both extremely high magnetic flux density and good primary coating. In particular, the effect of reducing iron loss with a low magnetostriction or magnetic domain control material is remarkable.

【図面の簡単な説明】[Brief description of drawings]

【図１】Ｖ％−ηと製品Ｂ₈ との関係を示す図表。FIG. 1 is a chart showing the relationship between V% -η and product B ₈ .

【図２】Ｖ％−ηと一次再結晶温度と製品Ｂ₈ との関係
を示す図表。FIG. 2 is a chart showing the relationship between V% -η, primary recrystallization temperature, and product B ₈ .

【図３】二次再結晶温度の８００℃〜最高到達温度の平
均昇温速度（℃／hr）とＢ₈ との関係を示す図表と一次
被膜外観検査結果を示す。FIG. 3 shows a diagram showing the relationship between the average temperature rising rate (° C./hr) of the secondary recrystallization temperature of 800 ° C. to the maximum reached temperature (° C./hr) and B ₈ and the appearance inspection result of the primary coating.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 熊野 知二 東京都千代田区大手町２−６−３ 新日本 製鐵株式会社内 (72)発明者 岩永 功 東京都千代田区大手町２−６−３ 新日本 製鐵株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoji Kumano 2-6-3 Otemachi, Chiyoda-ku, Tokyo Within Nippon Steel Corporation (72) Inventor Isao Iwanaga 2-6-Otemachi, Chiyoda-ku, Tokyo 3 Within Nippon Steel Corporation

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 重量比で、Ｓｉ：１〜４％、Ａｌ：０．
０１〜０．０５％、Ｖ：０．０１〜０．１０％、Ｓ：
０．０１％以下を含む鋼を溶製し、１０００〜１２７０
℃のスラブ均熱温度、８５０℃以上の熱延仕上温度の熱
間圧延、冷間圧延、一次再結晶焼鈍および二次再結晶焼
鈍を基本工程とする方向性電磁鋼板の製造において、さ
らに溶鋼中および熱間圧延後から二次再結晶焼鈍工程の
二次再結晶焼鈍温度９５０℃に到達する前のいずれかの
工程で鋼に合計Ｎ：０．０１〜０．０４％の窒素添加を
行い、かつその合計のＮ量に対してξ＝Ｎ％−（１４／
５１）Ｖ％と定義したとき０．００２％≦ξ≦０．０４
％を満たし、かつ、η＝Ａｌ％−（２７／１４）ξと定
義したときＶ％−ηが０．００５％≦Ｖ％−η≦０．０
７％を満たすようにせしめ、さらに、一次再結晶焼鈍温
度Ｔ₀ を７８０℃＋１００（Ｖ％−η）≦Ｔ₀ ≦７８０
℃＋５０００（Ｖ％−η）で行い、かつ、上記の二次再
結晶焼鈍前にフォルステライトを主体とする一次被膜形
成のために塗布するマグネシアの中にアンチモン系の化
合物を０．０５〜５．０％添加するか、あるいはなにも
意図的に添加しない場合は二次再結晶焼鈍での８００℃
〜最高到達温度の平均昇温速度を毎時０．１〜８０℃と
し、一方、マグネシアの中にボロン系、ストロンチウム
・バリウム系、炭・窒化物系、硫化物系、塩化物系の１
種または２種以上を合計０．０５〜５．０％添加する場
合は二次再結晶焼鈍での８００℃〜最高到達温度の平均
昇温速度を毎時５〜４００℃とすることを特徴とする高
磁束密度方向性電磁鋼板の製造法。1. A weight ratio of Si: 1 to 4% and Al: 0.
01-0.05%, V: 0.01-0.10%, S:
Steel containing 0.01% or less is melted and 1000 to 1270
Slab soaking temperature of ℃, hot rolling finishing temperature of 850 ℃ or more hot rolling, cold rolling, primary recrystallization annealing and secondary recrystallization annealing in the production of grain oriented electrical steel sheet And nitrogen is added to the steel in a total amount of N: 0.01 to 0.04% in any step after reaching the secondary recrystallization annealing temperature of 950 ° C. in the secondary recrystallization annealing step after hot rolling, And for the total amount of N, ξ = N% − (14 /
51) 0.002% ≦ ξ ≦ 0.04 when defined as V%
%, And when defined as η = Al% − (27/14) ξ, V% −η is 0.005% ≦ V% −η ≦ 0.0
7%, and the primary recrystallization annealing temperature T ₀ is 780 ° C. + 100 (V% −η) ≦ T ₀ ≦ 780.
C. + 5000 (V%-. Eta.), And before the secondary recrystallization annealing, 0.05 to 5 antimony-based compounds are added to magnesia which is applied to form a primary coating mainly composed of forsterite. 0.0% in secondary recrystallization annealing, if not added intentionally.
~ The average temperature increase rate of the highest temperature is set to 0.1 ~ 80 ℃ per hour, while one of boron, strontium / barium, carbon / nitride, sulfide, and chloride is contained in magnesia.
In the case of adding 0.05 to 5.0% in total of two or more kinds, it is characterized in that the average rate of temperature increase from 800 ° C. to the maximum reached temperature in the secondary recrystallization annealing is 5 to 400 ° C. per hour. High magnetic flux density grain oriented electrical steel sheet manufacturing method. 【請求項２】 さらにＮｂ：０．００８〜０．０８％を
溶鋼中に含み、また、請求項１記載の式中のＶ％に代え
てＶ％＋（５１／９３）Ｎｂ％と置くことを特徴とする
請求項１記載の製造法。2. Further, Nb: 0.008 to 0.08% is contained in the molten steel, and V% + (51/93) Nb% is set in place of V% in the formula of claim 1. The manufacturing method according to claim 1, wherein: 【請求項３】 Ｖの代わりにＮｂ：０．００８〜０．０
８％を溶鋼中に含み、また、請求項１記載の式中のＶ％
に代えて（５１／９３）Ｎｂ％と置くことを特徴とする
請求項１記載の製造法。3. Nb: 0.008 to 0.0 instead of V
8% in molten steel, and V% in the formula according to claim 1.
The production method according to claim 1, wherein (51/93) Nb% is set instead of.