JP4292616B2 - Manufacturing method of electrical steel sheet - Google Patents

Description

【００２２】
ε_i(0) は鋼板が熱間仕上げ圧延機の第ｉ番目のスタンドで受ける歪み量、ｔ_i は鋼板が第ｉ番目のスタンドから最終スタンドに入るまでの時間（秒）、ｆは熱間仕上げ圧延機を構成するスタンドの総数 (台）、Ｔi は第ｉ番目のスタンドにおける鋼板の圧延温度（Ｋ）を意味する。
【００２４】
【発明の実施の形態】
まず、この発明の製造条件について説明する。
先願（特願平10−213883号公報) では、特殊な条件下で熱間圧延した場合に、フェライト粒界から（０１５）〔１００〕方位が生成することについて開示したが、本発明者らは、さらに研究を重ねた結果、特殊な熱延条件に依存することなく、熱間圧延後の再結晶過程で容易に（０１５）〔１００〕方位を発現させること、より具体的には前記再結晶後の集合組織を、（０１５）〔１００〕方位強度／ランダム方位強度の比が3.0 以上である組織にすることによって、Ｌ方向及びＣ方向の磁気特性が優れた電磁鋼板が得られること、更には、熱間仕上げ圧延機の最終スタンドに入る際の鋼板の歪みの回復挙動と最終スタンドでの圧下率が、（０１５）〔１００〕方位粒の生成に強く影響を及ぼすことを見出し、この発明を完成するに至ったものである。
【００２５】
(I) 冷間圧延前の鋼板の（０１５）〔１００〕方位の強度：ランダム方位の強度の3.0 倍以上の範囲
冷間圧延前の鋼板中の（０１５）〔１００〕方位粒の密度が増加すると、冷間圧延、仕上げ焼鈍後の面上立方方位の密度が増加するとともに、 ＜１１１＞//ＮＤ方位が減少し、磁気特性が向上する。そのため、冷間圧延前の鋼板中の（０１５）〔１００〕方位の強度はランダム組織のそれの 3.0倍以上の範囲にすることが必要である。
【００２６】
この発明の集合組織を形成ための方法は、以下のとおりである。
【００２７】
(II)前記集合組織を形成するための条件
(i)熱間仕上げ圧延機の第１スタンドに入る際の鋼板の組織がフェライト単相組織であること
前述の先願（特平願10−213883号公報）の発明では、熱間仕上げ圧延後の焼鈍で発現する（０１５）〔１００〕方位粒が、フェライト結晶粒界から生成することを開示しているが、この発明でも、熱問仕上げ圧延時にオーステナイト相を生じる成分組成を有する鋼については、Ａr₁変態点以下にするなどして、フェライト単相域にしておく必要がある。
【００２８】
(ii)熱間仕上げ圧延機の最終スタンド入る際の鋼板は、下記(a) 式で定義されるスタンド間での回復による歪エネルギーの解放を考慮した有効蓄積歪み量Ｒが1.0 以上であること
【化３】

（０１５）〔１００〕方位粒は、未再結晶のフェライト粒界から生成するものであり、そこから生成する（０１５）〔１００〕方位粒は、もとのフェライト粒の方位によらず、新たに発現する特異な結晶方位である。
【００２９】
一方、結晶粒界には、熱間圧延を行うことによって歪エネルギーが導入されて蓄積するが、この蓄積された歪エネルギーを、熱間圧延機を構成するスタンド間で回復によって解放してしまった場合には、粒界が湾曲し、張り出し機構（バルジング）によってサブグレイン、やがては再結晶が生じるようになる。
【００３０】
バルジングによって生成した再結晶化した結晶粒は、その生成機構からもとのフェライト粒の結晶方位をそのまま受け継ぐ傾向があるため、（０１５）〔１００〕方位粒を生成することはできない。
【００３１】
従って、本発明者らは、フェライト粒を未再結晶にし、かつ回復による歪エネルギーの解放を起こさずにフェライト粒界に歪みを蓄積させておくことによって、この蓄積された歪エネルギーが駆動力となって、（０１５）〔１００〕が生成するものと考え、本発明における数多くの実験を行なった結果、実験式として、熱間仕上げ圧延時のスタンド間での回復による歪エネルギーの解放を考慮した蓄積歪み量、すなわち、最終スタンドに入る際の有効蓄積歪み量Ｒを表わす上記(a) 式を導くことに成功したのである。
【００３２】
そして、本発明者らは、さらに実験を重ねた結果、この歪み量Ｒを1.0 以上とすることで、最終スタンドに入る際の粒界の回復が抑制されるとともに、歪みエネルギーが蓄積され、（０１５）〔１００〕がより強く発現できることを見出した。
【００３３】
図１は、Siを2.0 wt％含有する鋼スラブを熱間粗圧延し、(a) 式で求めた有効蓄積歪み量Ｒ及び熱間仕上げ圧延機の最終スタンドでの圧下率を変化させた場合に得られる鋼板の、ランダム強度に対する（０１５）〔１００〕方位の強度の比を測定した結果をプロットしたものである。
【００３４】
この図からも明らかなように、有効蓄積歪み量Ｒが1.0 以上のとき、熱間仕上げ圧延機の最終スタンドでの圧下率が20％以上であることを前提条件として、前記強度比が3.0 倍以上であることがわかる。
【００３５】
尚、有効蓄積歪み量Ｒを1.0 以上にするための具体的に製造条件としては、例えば、熱延温度の低下、又は高速熱間圧延によるスタンド間での滞在時間の短縮等が挙げられる。
【００３６】
(iii) 熱間仕上げ圧延機の最終スタンドでの圧下率が20％以上であること
同様に、（０１５）〔１００〕が発現できる歪み量を確保するためには、熱間仕上げ圧延機の最終スタンドでの圧下率が20％以上でなければならない。これは、上記のように、バルジングの生じていない粒界からの（０１５）〔１００〕方位が核生成するための駆動力を与えるのに必要であるからである。以上のことは、上述した図１に示す実験結果からも明らかである。尚、Ｌ方向及びＣ方向の磁気特性をより一層向上させる必要がある場合には、上記圧下率を30％以上にすることがより好適である。
【００３７】
従って、この発明において、前記集合組織を形成するための条件としては、熱間仕上げ圧延機の第１スタンドに入る際の鋼板の組織がフェライト単相であること、前記有効蓄積歪み量Ｒを1.0以上にすること、及び熱間仕上げ圧延機の最終スタンドでの圧下率を20％以上とすることである。
【００３８】
（III）鋼片中の成分組成
この発明では、前記鋼片に、Si：4.0wt％以下、Mn：2.0wt％以下、Ｐ：0.3wt％以下、Al：2.0wt％以下を含有する。理由は以下の通りである。
【００３９】
Si：4.0wt％以下
Siは比抵抗を増大させ、渦電流損を低減させる効果があり、この発明では有効な添加元素である。しかし、Si含有量が4.0％を越えると、磁束密度の低下が大きくなるとともに加工性が低下する。従って、Siの含有量は4.0wt％以下に限定する。
【００４０】
Mn：2.0wt％以下、Al：2.0wt％以下
MnとAlは、ともに鋼の脱酸剤として、また比抵抗を増大させ渦電流損を低減させる効果がある有効な元素である。しかし、MnとAlの含有量がそれぞれ2.0wt％をを越えると、磁束密度の低下や加工性の低下が大きくなる。従って、MnとAlの含有量は2.0wt％以下の範囲に限定する。
【００４１】
Ｐ：0.3wt％以下
Ｐは比抵抗を増大させ、渦電流損を低減させる効果がある有効な元素である。しかし、0.3wt％を越えると加工性が低下する。従って、Ｐの含有量は0.3wt％以下の範囲に限定する。
【００４２】
(IV)その他の製造条件
この発明の製造方法は、上記(I)，(II)及び(III)に記載した条件を満足することが少なくとも必要であるが、これに加えて、以下に示す製造条件を満足することがより好適である。
【００４３】
(i）冷間圧延での圧下率：50〜85％
熱間圧延により形成された集合組織を冷間圧延する際に、冷間圧延で圧下しすぎると、＜１１１＞//ＮＤ方位の増加を招く傾向があるため、冷間圧延の圧下率の上限は85％にするのが望ましい。また、前記圧下率が小さすぎると、面上立方方位が減少するため、前記圧下率は50％以上であることが望ましい。
【００４４】
尚、上述したところは、この発明の実施形態の一例を示したにすぎず、請求の範囲において種々の変更を加えることができる。
【００４５】
【実施例】
表１に示す鋼を転炉溶製し、連続鋳造により200mm 厚さの鋼片（鋼スラブ）とした。これらの鋼スラブを1200℃に再加熱し、40mm厚のシートバーに熱間粗圧延を行い、引き続き熱間仕上げ圧延を行った。その際の熱間仕上げ圧延条件を表２に示す。熱間仕上げ圧延後の板厚は2.3mm とした。
【００４６】
そして、熱間仕上げ圧延後に 850〜1000℃で再結晶処理を行い、次いで、冷間圧延を行い板厚を0.50mmとし、その後、 850〜1000℃で仕上げ焼鈍を行うことによって電磁鋼板（鋼Ｎo.１〜27）を製造した。
表２に、各製造条件と共に、集合組織及び磁気特性を併記した。
尚、集合組織の測定は、 シュルツＸ線回折法により（１１０）、（２００）、（２１１）極点図を求め、３次元方位分布密度を計算する方法によって行なった。
【００４７】
【表１】

【００４８】
【表２】

【００４９】
以下に、本発明による磁気特性の改善結果について表２に基づいて述べる。ここで、本発明には、鉄損改善のための比抵抗増加成分も含まれている。したがって、表２に示す磁気特性は、鉄損と磁束密度の双方の結果から総合的に評価した。
【００５０】
この発明に従って製造した鋼１〜３, ７〜10,14 〜17, 22〜24と、この発明の製造条件のうちの少なくとも１つが適正範囲外である条件で製造した鋼Ｎo.４〜６，11〜13,18 〜21,25 〜27とを鋼種ごとに比較すると、前者は、後者に比べて磁気特性が顕著に優れているのがわかる。
【００５１】
また、表２中の熱間圧延及び再結晶後の（０１５）［１００］の強度のランダム組織の強度に対する比率は3.0 倍以上とすることにより、仕上げ焼鈍後の、面上立方方位の強度の前記比率は2.0 倍以上、かつ、ゴス方位の強度の前記比率は2.0 〜10.0倍の範囲となり、そして、＜１１１＞//ＮＤ方位の強度の前記比率は2.0 倍以下となり、良好な磁気特性を有しているのがわかる。
【００５２】
よって、この発明では、熱間圧延及び再結晶後の（０１５）［１００］の集積度のランダム組織に対する比率を3.0 倍以上とし、仕上げ焼鈍後の、面上立方方位の強度の前記比率を2.0 倍以上、かつ、ゴス方位の強度の前記比率を2.0 〜10.0倍の範囲とし、そして、 ＜１１１＞//ＮＤ方位の強度の前記比率を2.0 倍以下にすることがより好適である。
【００５３】
【発明の効果】
この発明の製造方法によれば、Ｌ方向及びＣ方向の磁気特性に優れた電磁鋼板の製造が可能になり、しかも、特殊または複雑な製造条件や工程に頼ることなく、通常の製造工程で行えるため、工業的かつ安価に製造することができる。
【図面の簡単な説明】
【図１】 有効蓄積歪み量Ｒ及び熱間仕上げ圧延機の最終スタンドでの圧下率を変化させた場合に得られる鋼板の、ランダム強度に対する（０１５）〔１００〕方位の強度の比を測定した結果をプロットしたものである。[0001]
BACKGROUND OF THE INVENTION
The present invention is used for an AC magnetic core and is particularly excellent in magnetic properties in two directions, ie, a rolling direction (hereinafter referred to as “L direction”) and a direction perpendicular thereto (hereinafter referred to as “C direction”). It relates to the manufacturing method.
[0002]
[Prior art]
Iron core materials for transformers and motors are required to have high magnetic flux density and low iron loss in order to increase the efficiency and miniaturization of these devices. As a magnetic alloy used for this type of iron core material, an Fe—Si alloy is known and widely used as a non-oriented electrical steel sheet.
[0003]
Various attempts have been made to improve the texture in order to improve the magnetic properties of the non-oriented electrical steel sheet. Among them, it is described in JP-A-54-110121 and the like that iron loss is reduced and magnetic flux density is particularly increased by enriching crystal grains of (011) [100] orientation, that is, Goth orientation. Has been. Usually, the Goth orientation improves the magnetic characteristics in the L direction, and as a result, the average characteristics including the C direction are improved.
[0004]
However, since the magnetic properties in the C direction are not sufficiently improved, there is a limit to improving the average properties.
[0005]
On the other hand, it is known that the {100} <001> orientation, that is, the in-plane cubic orientation, simultaneously improves the magnetic properties in the two directions of the L direction and the C direction.
[0006]
However, in order to obtain a structure accumulated only in the cubic orientation on the surface, a method of performing high temperature intermediate annealing described in Japanese Patent Publication No. 46-23814, two directions described in Japanese Patent Laid-Open No. 05-271883. Rolling method, quenching ribbon method described in JP-A No. 05-306438, γ-α transformation method accompanying decarburization described in JP-A No. 01-108345, etc. In addition, it takes a long time and costs are high, and it is assumed that industrial practicality cannot be established.
[0007]
Furthermore, as a method for improving the magnetic characteristics, it is important to suppress the orientation that deteriorates the magnetic characteristics as well as enrich the crystal grains with the orientation that improves the magnetic characteristics.
[0008]
There are crystal grains with <111> // ND (direction perpendicular to the steel plate surface) orientation as the orientation that degrades the magnetic properties, and it is desirable to suppress the formation of these crystal grains. Except for the case of using the means, it was difficult to reduce the crystal grains of this orientation in the manufacturing method of the non-oriented electrical steel sheet.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a manufacturing method for manufacturing industrially and inexpensively an electrical steel sheet that is particularly excellent in the magnetic properties in the two directions of the L direction and the C direction.
[0010]
[Means for Solving the Problems]
As a result of extensive research on means for practically improving the properties of non-oriented electrical steel sheets, the present inventors have found that the texture can be controlled by hot finish rolling after hot rough rolling. Proposed in No. 10-213883.
[0011]
The essence of this is that hot ferrite rolling is performed on coarse ferrite grains in an unrecrystallized temperature range and under conditions where the ratio of hot rolling speed / reduction ratio at each stand is large, that is, under conditions of a large hot rolling speed. In the recrystallization process after hot rolling, (015) [100] oriented grains were produced, and this utilized the fact that they developed as {100} <001> oriented grains that were most favorable for magnetic properties during cold rolling and annealing. Is.
[0012]
Incidentally, the point that (015) [100] grains change to {001} <100> by cold rolling and recrystallization annealing is already known (Taoka et al .: Iron and Steel, 54 (1968) 162.). However, the production method capable of industrially expressing (015) [100] was completely unknown.
[0013]
For this reason, the present inventors have found a technique for the expression and control of (015) [100] grains, and further, the presence of (015) [100] degrades the magnetic properties after cold rolling annealing. As the number of ND fibers decreases and (011) [100], which improves the magnetic properties in the L direction, increases, it has been newly found that the magnetic properties of the average in the L direction and the C direction are improved.
[0014]
However, when applying the above technique to an actual process, it is important to increase the ratio of hot rolling speed / shrinkage ratio in each rolling stand, that is, to increase the hot rolling speed, among the above manufacturing conditions. However, it is currently difficult to use a large hot rolling speed in the manufacturing process of the electromagnetic steel sheet in terms of the capability of the rolling mill, shape control, and the like.
[0015]
The invention of the above-mentioned prior application (Japanese Patent Application No. 10-213883) is based on the fact that special recrystallized grains having the (015) [100] orientation are generated in the recrystallization process after hot rolling under special conditions. However, the present inventors have newly found that the (015) [100] orientation can be easily expressed in the recrystallization process after hot rolling without depending on special hot rolling conditions. I found it.
[0016]
In addition, by defining the amount of strain considering the recovery rate between each stand up to just before the final stand during hot finish rolling and the reduction rate at the final stand, the (015) [100] orientation can be expressed more easily. I also found out that I can do it.
[0017]
That is, the present invention contains, by mass%, Si: 4.0% or less, Mn: 2.0% or less, P: 0.3% or less, Al: 2.0% or less, the balance Fe and inevitable impurities A hot-rolled sheet is obtained by subjecting a steel slab comprising hot rolling to hot finish rolling under the conditions shown in (1), (2) and (3) below, followed by recrystallization. (015) [100] The ratio of [100] orientation strength / random orientation strength is 3.0 or more, and then cold rolling and annealing are performed.
[0020]
1
(1) The structure of the steel sheet when entering the first stand of the hot finish rolling mill is a ferrite single phase structure.
(2) The steel sheet when entering the final stand of the hot finish rolling mill has an effective accumulated strain amount (R) considering the release of strain energy due to recovery between the stands defined by the following formula (a). Must be 1.0 or higher.
(3) The rolling reduction at the final stand of the hot finish rolling mill should be 20% or more.
[0021]
2
[Chemical formula 2]

[0022]
ε _i (0) is the amount of strain that the steel sheet undergoes at the i-th stand of the hot finish rolling mill, t _i is the time (seconds) until the steel sheet enters the final stand from the i-th stand, and f is hot The total number (stands) of stands constituting the finish rolling mill, Ti means the rolling temperature (K) of the steel plate in the i-th stand.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
First, the manufacturing conditions of the present invention will be described.
The prior application (Japanese Patent Application No. 10-213883) discloses that the (015) [100] orientation is generated from the ferrite grain boundary when hot rolled under special conditions. As a result of further research, it is possible to easily develop the (015) [100] orientation in the recrystallization process after hot rolling without depending on special hot rolling conditions. By making the texture after crystallization into a structure in which the ratio of (015) [100] orientation strength / random orientation strength is 3.0 or more, an electrical steel sheet having excellent magnetic properties in the L direction and the C direction can be obtained, Furthermore, it was found that the strain recovery behavior of the steel sheet when entering the final stand of the hot finish rolling mill and the reduction rate at the final stand strongly influence the formation of (015) [100] oriented grains. Which led to the completion of the invention. That.
[0025]
(I) Strength of (015) [100] orientation of steel sheet before cold rolling: range of 3.0 times or more of random orientation strength Increase of density of (015) [100] orientation grain in steel plate before cold rolling Then, the density of the cubic orientation on the surface after cold rolling and finish annealing increases, the <111> // ND orientation decreases, and the magnetic properties are improved. Therefore, the strength of the (015) [100] orientation in the steel sheet before cold rolling needs to be in the range of 3.0 times or more that of the random structure.
[0026]
The method for forming the texture of the present invention is as follows.
[0027]
(II) Conditions for forming the texture
(i) The structure of the steel sheet when entering the first stand of the hot finish rolling mill is a ferrite single phase structure. In the invention of the previous application (Japanese Patent Application No. 10-213883), after the hot finish rolling (015) [100] oriented grains appearing in the annealing of steel are disclosed to be generated from ferrite grain boundaries. In this invention as well, steel having a component composition that generates an austenitic phase during hot finish rolling is disclosed. It is necessary to keep the ferrite single phase region, for example, below the Ar ₁ transformation point.
[0028]
(ii) The steel sheet when entering the final stand of the hot finish rolling mill has an effective accumulated strain amount R of 1.0 or more in consideration of release of strain energy due to recovery between stands defined by the following formula (a) [Chemical 3]

The (015) [100] oriented grains are generated from unrecrystallized ferrite grain boundaries, and the (015) [100] oriented grains generated therefrom are new regardless of the orientation of the original ferrite grains. Is a unique crystal orientation.
[0029]
On the other hand, strain energy is introduced and accumulated in the grain boundaries by performing hot rolling, but the accumulated strain energy has been released by recovery between the stands constituting the hot rolling mill. In some cases, the grain boundaries are curved, and subgrains and eventually recrystallization occur due to the overhang mechanism (bulging).
[0030]
Since the recrystallized crystal grains generated by bulging tend to inherit the crystal orientation of the original ferrite grains from the generation mechanism, (015) [100] oriented grains cannot be generated.
[0031]
Therefore, the present inventors have made the accumulated strain energy as a driving force by making the ferrite grains non-recrystallized and accumulating strain at the ferrite grain boundaries without causing the release of strain energy by recovery. Therefore, (015) [100] is considered to be generated, and as a result of many experiments in the present invention, the release of strain energy due to recovery between stands during hot finish rolling was considered as an empirical formula. It succeeded in deriving the above equation (a) representing the accumulated strain amount, that is, the effective accumulated strain amount R when entering the final stand.
[0032]
Further, as a result of further experiments, the present inventors set the strain amount R to 1.0 or more, thereby suppressing the recovery of grain boundaries when entering the final stand and accumulating strain energy. 015) It was found that [100] can be expressed more strongly.
[0033]
Fig. 1 shows a case where hot slabs containing 2.0 wt% Si are hot-rolled and the effective accumulated strain amount R obtained by equation (a) and the rolling reduction ratio at the final stand of the hot finish rolling mill are changed. The results obtained by measuring the ratio of the strength of the (015) [100] orientation to the random strength of the steel sheet obtained in Fig. 3 are plotted.
[0034]
As is clear from this figure, when the effective accumulated strain amount R is 1.0 or more, the strength ratio is 3.0 times on the precondition that the rolling reduction at the final stand of the hot finish rolling mill is 20% or more. It turns out that it is above.
[0035]
Specific production conditions for setting the effective accumulated strain amount R to 1.0 or more include, for example, a reduction in hot rolling temperature or a reduction in residence time between stands by high-speed hot rolling.
[0036]
(iii) The rolling reduction at the final stand of the hot finish rolling mill is 20% or more. Similarly, in order to secure the amount of distortion that can express (015) [100], the final finish of the hot finish rolling mill The rolling reduction at the stand must be at least 20%. This is because, as described above, the (015) [100] orientation from the grain boundary where no bulging occurs is necessary to provide a driving force for nucleation. The above is clear from the experimental results shown in FIG. In addition, when it is necessary to further improve the magnetic properties in the L direction and the C direction, it is more preferable to set the rolling reduction to 30% or more.
[0037]
Therefore, in the present invention, the condition for forming the texture is that the structure of the steel sheet when entering the first stand of the hot finish rolling mill is a ferrite single phase, and the effective accumulated strain amount R is 1.0. The above is to make the reduction ratio at the final stand of the hot finish rolling mill 20% or more.
[0038]
(III) Component composition in steel slab
In the present invention, the steel slab contains Si: 4.0 wt% or less, Mn: 2.0 wt% or less, P: 0.3 wt% or less, and Al: 2.0 wt% or less. The reason is as follows.
[0039]
Si: 4.0wt% or less
Si has an effect of increasing specific resistance and reducing eddy current loss, and is an effective additive element in the present invention. However, if the Si content exceeds 4.0%, the magnetic flux density is greatly reduced and the workability is reduced. Therefore, the Si content is limited to 4.0 wt% or less.
[0040]
Mn: 2.0 wt% or less, Al: 2.0 wt% or less
Both Mn and Al are effective elements that are effective as steel deoxidizers and increase specific resistance and reduce eddy current loss. However, when the contents of Mn and Al each exceed 2.0 wt%, the magnetic flux density and workability are greatly reduced. Therefore, the contents of Mn and Al are limited to the range of 2.0 wt% or less.
[0041]
P: 0.3wt% or less
P is an effective element that has an effect of increasing specific resistance and reducing eddy current loss. However, if it exceeds 0.3 wt%, the workability decreases. Therefore, the P content is limited to a range of 0.3 wt% or less.
[0042]
(IV) Other manufacturing conditions
The production method of the present invention needs to satisfy at least the conditions described in the above (I), (II) and (III), but in addition to this, it is more preferable to satisfy the production conditions shown below. Is preferred.
[0043]
(i) Cold rolling reduction: 50-85%
When cold rolling a texture formed by hot rolling, if it is over-rolled by cold rolling, it tends to cause an increase in <111> // ND orientation, so the upper limit of the cold rolling reduction ratio 85% is desirable. Further, if the rolling reduction is too small, the on-plane cubic orientation decreases, and therefore the rolling reduction is preferably 50% or more.
[0044]
The above description only shows an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.
[0045]
【Example】
The steel shown in Table 1 was melted in a converter and formed into a steel piece (steel slab) with a thickness of 200 mm by continuous casting. These steel slabs were reheated to 1200 ° C., hot rough rolling was performed on a 40 mm thick sheet bar, and then hot finish rolling was performed. Table 2 shows the hot finish rolling conditions at that time. The thickness after hot finish rolling was 2.3 mm.
[0046]
Then, after hot finish rolling, recrystallization treatment is performed at 850 to 1000 ° C., then cold rolling is performed to obtain a sheet thickness of 0.50 mm, and then finish annealing is performed at 850 to 1000 ° C. 0.1 to 27) were produced.
Table 2 shows the texture and magnetic properties together with the production conditions.
The texture was measured by a method of calculating (110), (200), (211) pole figures by Schulz X-ray diffraction method and calculating a three-dimensional orientation distribution density.
[0047]
[Table 1]

[0048]
[Table 2]

[0049]
Below, the improvement result of the magnetic characteristic by this invention is described based on Table 2. FIG. Here, the specific resistance increasing component for iron loss improvement is also included in the present invention. Therefore, the magnetic characteristics shown in Table 2 were comprehensively evaluated from the results of both iron loss and magnetic flux density.
[0050]
Steels 1 to 3, 7 to 10, 14 to 17, 22 to 24 manufactured in accordance with the present invention, and steels No. 4 to 6, manufactured on condition that at least one of the manufacturing conditions of the present invention is outside the proper range Comparing 11-13, 18-21, 25-27 for each steel type, it can be seen that the former has significantly better magnetic properties than the latter.
[0051]
In addition, the ratio of the strength of (015) [100] after hot rolling and recrystallization in Table 2 to the strength of the random structure is 3.0 times or more, so that the strength of the cubic orientation on the surface after finish annealing is increased. The ratio is 2.0 times or more, the ratio of Goss orientation strength is in the range of 2.0 to 10.0 times, and the ratio of <111> // ND orientation strength is 2.0 times or less, and good magnetic properties are obtained. You can see that it has.
[0052]
Therefore, in the present invention, the ratio of the degree of accumulation of (015) [100] to the random structure after hot rolling and recrystallization is set to 3.0 times or more, and the ratio of the in-plane cubic orientation strength after finish annealing is set to 2.0. More preferably, the ratio of the Goss azimuth strength is in the range of 2.0 to 10.0 times, and the <111> // ND azimuth strength ratio is 2.0 times or less.
[0053]
【The invention's effect】
According to the manufacturing method of the present invention, it is possible to manufacture an electrical steel sheet having excellent magnetic properties in the L direction and the C direction, and it can be performed in a normal manufacturing process without depending on special or complicated manufacturing conditions and processes. Therefore, it can be manufactured industrially and inexpensively.
[Brief description of the drawings]
1 shows the ratio of the strength of a (015) [100] orientation to the random strength of a steel sheet obtained by changing the effective accumulated strain amount R and the rolling reduction at the final stand of a hot finish rolling mill. The results are plotted.

Claims (1)

A steel slab containing, in mass%, Si: 4.0% or less, Mn: 2.0% or less, P: 0.3% or less, Al: 2.0% or less, and the balance Fe and unavoidable impurities is heated. After hot rough rolling, hot finish rolling is performed under the conditions shown in the following 1 (1), (2) and (3), followed by recrystallization, whereby the texture of the hot rolled sheet is (015). ) [100] A method for producing an electrical steel sheet , wherein the ratio of azimuth strength / random azimuth strength is 3.0 or more, followed by cold rolling and annealing.
1
(1) The structure of the steel sheet when entering the first stand of the hot finish rolling mill is a ferrite single phase structure.
(2) The steel sheet that enters the final stand of the hot finish rolling mill has an effective accumulated strain amount (R) that takes into account the release of strain energy due to recovery between the stands defined by equation (a) below. Must be 1.0 or higher.
(3) The rolling reduction at the final stand of the hot finish rolling mill should be 20% or more.
2

epsilon _{i (0)} is the amount of strain the steel sheet is subjected at the i-th stand of the hot finish rolling machine, t _i is the time until the steel sheet enters the final stand from the i-th stand (s), f is hot The total number (stands) of the stands constituting the finish rolling mill, T _i means the rolling temperature (K) of the steel plate in the i-th stand.

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