JPH0425346B2

JPH0425346B2 -

Info

Publication number: JPH0425346B2
Application number: JP61098901A
Authority: JP
Inventors: Akira Sakaida; Ichiro Tateno; Shinichi Nishida
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 1986-04-28
Filing date: 1986-04-28
Publication date: 1992-04-30
Also published as: JPS62256917A

Description

[Detailed description of the invention]

（産業上の利用分野）本発明は、回転機の回転部に鉄心として用いら
れる電磁鋼板、特に回転時の応力あるいは加減速
時の繰返し応力に耐え得る優れた機械特性と磁気
特性、即ち鉄損、磁束密度を劣化させることなく
具備した高抗張力無方向性電磁鋼板に関するもの
である。（従来の技術）近年、エレクトロニクスの発達により回転機の
駆動システムの機能が高度化し、さまざまな回転
駆動制御が可能となつてきた。即ち、駆動電源の
周波数を制御することにより、可変速運転、高周
波数以上での高速運転を可能とした回転機が増加
してきた。一方、メカトロニクスの発展により、
回転機の高速化の要求が高まり、さらに従来、高
速回転機は比較的小容量に限られていたが、この
傾向は中・大型の回転機分野にも広がりつつあ
る。このような高速回転機を実現するには、高速回
転に耐え得る構造の回転子とする必要がある。一
般に、回転する物体に作用する遠心力は回転半径
に比例し、回転速度の２乗に比例して大きくなる
ので、中・大型の高速回転機ではその回転子に作
用する力が60Kg／mm²を越える場合がある。また、
超大型の回転機の場合、回転数が比較的低くても
回転子の直径が大きいために、結果的に60Kg／mm²
以上の応力が作用する場合があり、回転子には高
抗張力の素材が必要となる。さらに、可変速運転
が必要な回転機では加減速が頻繁に行なわれるた
め、素材として単に抗張力が高いだけでなく、繰
返し応力に対して疲労破壊する限度応力（疲労
限）の高い素材でなければならない。通常、回転機の回転子には積層した無方向性電
磁鋼板が使われるが、前記のような回転機では所
要の機械強度を満足できない場合があり、その際
には中実の鋳鋼製の回転子などが採用されてい
る。しかし、回転機の回転子は電磁気現象を利用
するものであるから、その素材としては前述の機
械特性と同時に磁気特性が優れていることが要求
される。回転子用の鉄心素材に要求される磁気特性のう
ち、特に重要であるのは鉄損と磁束密度である。
回転子に発生する鉄損の主たるものは、回転子鉄
心表面に生じるリツプル損と呼ばれる高周波磁束
による損失で、その周波数f_Rは次式のように表わ
される。 f_R＝２・f₀・Ｍ／Ｐここにf₀：駆動電源の周波数Ｍ：固定子鉄心の歯数（テイース数）Ｐ：回転機の磁極数一例として、駆動電源の周波数を商用周波数の
２倍程度とした２極回転機の場合を考えると、そ
のリツプル磁束の周波数は１〜10kHzの範囲とな
る。従つて、このような回転子用鉄心素材としては
上記の周波数領域における鉄損が小さいものが望
ましい。しかし、前述の中実鋳鋼の回転子は一体
ものであるために、高周波領域では渦電流損失が
非常に大きくなつて、電磁鋼板を積層してなる回
転子を用いた場合に比べ、回転機としての効率が
数％低いと言われている。もう一つの重要な磁気特性である。回転子鉄心
素材の磁束密度が低いと、所要のトルクを発生さ
せるために必要な磁束を回転子に流すために、励
磁アンペアターンを大きくしなければならない。
これは励磁コイルでの銅損の増加につながるた
め、回転機の総合的な効率の低下を招く。即ち、
中実鋳鋼製の回転子から、機械特性および鉄損と
もに優れた素材を積層した回転子に置き換えれ
ば、鉄損は確実に減少するが、その素材の磁束密
度が低いと銅損が増加し、場合によつては鉄損の
減少分が相殺されて、効率が向上しないこともあ
りうる。このように、かかる回転機の回転子鉄心素材と
しては、機械的には高い抗張力と疲労強度を有
し、かつ磁気的には高周波数における鉄損が低
く、磁束密度が高いことを同時に満足するもので
なければならない。鋼板の機械強度を高める手段として、冷延鋼板
の分野で一般的に用いられる方法には、固溶硬
化、析出硬化、細粒化による硬化、変態組織によ
る硬化などがあるが、一般に、高い機械強度と低
鉄損・高磁束密度という優れた磁気特性とは相反
する関係にあり、これらを同時に満足させるのは
困難であつた。公知の技術として、例えば特開昭60−238421号
公報記載の方法のようにSi含有量を3.5〜7.0％と
高め、これに固溶硬化の大きい元素を添加し、抗
張力を高める方法が提案されているが、この方法
ではSi含有量に依存している割合が高いために、
熱延板から最終冷延厚みに圧延するに際して100
〜600℃の温間圧延が必要という欠点があつた。
さらに、この技術によつて得られる鋼板の磁束密
度はB₅₀は1.56〜1.61Tと極めて低いという大きな
問題があつた。また特開昭61−9520号公報では、Si含有量を高
め、これに固溶硬化の大きい元素を添加した溶鋼
を急冷凝固法により鋼帯とし、これを冷間あるい
は熱間圧延し、さらに焼鈍を施して、抗張力が高
く、鉄損の低い高抗張力無方向性電磁鋼板を製造
する方法が提案されている。この技術によれば、
Si含有量を高めても急冷凝固法であるため、従来
の圧延による製造法のように材料の脆化による制
約は緩和される。しかし、前出の技術と同様、例
えば70Kg／mm²以上の高抗張力を得るためには、Si
含有量を４〜4.5％と高めねばならず、磁束密度
B₅₀は非常に低くなるという問題があつた。一方、特開昭55−65349号公報などに提案され
ているように、センダスト系の、硬度が非常に高
く、透磁率の高い磁性材料を製造する技術がある
が、これらの材料は主に磁気ヘツドあるいは小型
の高周波トランスなどの静止器用である。本発明が対象としている回転機の回転子鉄心
は、通常、打ち抜きにより加工され、積層結束さ
れる。そして実際の回転機の運転状態では回転・
停止・加減速による繰返し応力を受ける。従つ
て、かかる回転子用鉄心材料としては、打ち抜き
加工で割れなどが発生することなく、かつ繰返し
応力に対する破壊強度の高いものでなければなら
ない。センダスト系の材料は機械的に高強度で耐
摩耗性に優れているが、反面、非常に脆いため、
上記の観点から回転機用には使用できなかつた。（発明が解決しようとする問題点）本発明の目的は、急冷凝固法などによらず、従
来の圧延技術で工業的規模の製造が可能な機械特
性ならびに磁気特性の優れた回転機用高抗張力無
方向性電磁鋼板およびその製造方法を提供しよう
とするものである。（問題点を解決するための手段）本発明の要旨とするところは下記のとおりであ
る。 (1) 重量で、Si：2.0％以上、3.5％未満、Ｃ：
0.008％以下、Ｐ：0.03％以上、0.2％未満、
Ni：0.3％以上、10％未満を含有し、残部Feお
よび不可避的不純物からなる、抗張力TS≧65
Kg／mm²、かつ高周波鉄損W_5/1000≦50W／Kg、
磁束密度B₅₀≧1.65Tの優れた機械的特性およ
び磁気特性を有する回転機用高抗張力無方向性
電磁鋼板。 (2) 重量で、Si：2.0％以上、3.5％未満、Ｃ：
0.008％以下、Ｐ：0.03％以上、0.2％未満、Ni
およびMnを0.3％≦Ni＋Mn＜10％の範囲内で
含有し、残部Feおよび不可避的不純物からな
る、抗張力TS≧65Kg／mm²、かつ高周波鉄損
W_5/1000≦50W／Kg、磁束密度B₅₀≧1.65Tの優
れた機械的特性および磁気特性を有する回転機
用高抗張力無方向性電磁鋼板。 (3) 重量で、Si：2.0％以上、3.5％未満、Ｃ：
0.008％以下、Ｐ：0.03％以上、0.2％未満、Ni
およびMnを0.3％≦Ni＋Mn＜10％の範囲内で
含有し、さらにAl：1.0％未満およびＢ：40±
30ppmの何れか１種を含み、残部Feおよび不
可避的不純物からなる、抗張力TS≧65Kg／mm²、
かつ高周波鉄損W_5/1000≦50W／Kg、磁束密度
B₅₀≧1.65Tの優れた機械的特性および磁気特
性を有する回転機用高抗張力無方向性電磁鋼
板。 (4) 重量で、Si：2.0％以上、3.5％未満、Ｃ：
0.008％以下、Ｐ：0.03％以上、0.2％未満、
Ni：0.3％以上、10％未満を含有し、残部Feお
よび不可避的不純物からなる鋼を、連続鋳造に
よつて或は鋳型に注入して鋼塊とし、これを分
塊圧延してスラブとし、次いで熱間圧延して熱
延板とし、そのまま或は熱延板焼鈍を施した後
酸洗し、冷間圧延して最終板厚とした後、650
℃以上、850℃未満の温度域で低温再結晶焼鈍
することを特徴とする回転機用高抗張力無方向
性電磁鋼板の製造方法。 (5) 重量で、Si：2.0％以上、3.5％未満、Ｃ：
0.008％以下、Ｐ：0.03％以上、0.2％未満、Ni
およびMnを0.3％≦Ni＋Mn＜10％の範囲内で
含有し、残部Feおよび不可避的不純物からな
る鋼を、連続鋳造によつて或は鋳型に注入して
鋼塊とし、これを分塊圧延してスラブとし、次
いで熱間圧延して熱延板とし、そのまま或は熱
延板焼鈍を施した後酸洗し、冷間圧延して最終
板厚とした後、650℃以上、850℃未満の温度域
で低温再結晶焼鈍することを特徴とする回転機
用高抗張力無方向性電磁鋼板の製造方法。 (6) 重量で、Si：2.0％以上、3.5％未満、Ｃ：
0.008％以下、Ｐ：0.03％以上、0.2％未満、Ni
およびMnを0.3％≦Ni＋Mn＜10％の範囲内で
含有し、さらにAl：1.0未満およびＢ：40±
30ppmの何れか１種を含み、残部Feおよび不
可避的不純物からなる鋼を、連続鋳造によつて
或は鋳型に注入して鋼塊とし、これを分塊圧延
してスラブとし、次いで熱間圧延して熱延板と
し、そのまま或は熱延板焼鈍を施した後酸洗
し、冷間圧延して最終板厚とした後、650℃以
上、850℃未満の温度域で低温再結晶焼鈍する
ことを特徴とする回転機用高抗張力無方向性電
磁鋼板の製造方法。他の要旨は、前記の成分を有する鋼を連続鋳造
あるいは鋼塊−分塊圧延によつてスラブとし、次
いで熱間圧延して、無焼鈍のままあるいは焼鈍し
た後、酸洗し、冷間圧延をして最終板厚となした
後、650℃以上、850℃未満の温度範囲で低温再結
晶させるところにある。以下にこの発明を詳細に説明する。まず成分を上記の範囲に限定した理由について
説明する。 Si：2.0％以上、3.5％未満 Siは鋼の固有抵抗を増し、過電流を減少させる
ので、鉄損減少に最も効果の大きい元素である。
同時にSiは抗張力を高めるにも有効な元素である
が、添加量が２％未満ではその効果が小さい。一
方、Siは前述のように鋼を脆化し、かつ製品の磁
束密度を低下させる。従つて、本発明では従来の
圧延技術で工業的規模の製造が可能で、かつ高い
磁束密度を確保するため、Si含有量を3.5％未満
とする。Ｃ：0.008％以下Ｃは鋼の強度を高めるが、一方、鉄損はＣ含有
量に対して急激に悪化するため、0.008％以下に
限定する。Ｐ：0.03％以上、0.2％未満Ｐは抗張力を高める効果が非常に大きい元素で
あるが、0.03％未満ではほとんど効果がない。一
方、Ｐは粒界に偏析し、鋳片・熱延板・冷延板を
脆化させる。従つて、工業的規模での連続鋳造・
熱間圧延・冷間圧延を可能とするために、0.2％
未満とする。 Mn，Ni：0.3％≦Mn＋Ni＜10％ Mn，Niはともに無方向性電磁鋼板の磁気特性
に与える悪影響が比較的小さく、固溶硬化によつ
て鋼の抗張力を高める効果が大きい。Mnは、鋼
の抗張力を高めるとともに固有抵抗を高くするか
ら、製品の高周波数域における鉄損を小さくする
点で有利である。Niは、無方向性電磁鋼板の磁
気特性に与える悪影響が比較的小さく、かつ鋼の
靭性を損なうことなしに抗張力を高める効果が大
きい元素である。Niを単独に添加する場合、0.3
％未満では効果を発現することができない。一
方、10％以上添加すると、無方向性電磁鋼板の磁
気特性、わけても磁束密度を低下させる。本発明においては、実施例にも示すように、
MnとNiを複合して添加することによつて、機械
的特性、わけても抗張力が高く、磁気特性に優れ
た無方向性電磁鋼板を得ることができる。複合添
加の場合においても、NiとMnの合計量で0.3％
未満では効果を発現することができない。一方、
10％以上添加すると、無方向性電磁鋼板の磁気特
性、わけても磁束密度を低下させ、本発明におけ
る技術的課題である1.65T以上の磁束密度を有す
る無方向性電磁鋼板を得ることができない。上に述べた各元素は、一般に、鋼を脆化させる
から、抗張力、靭性ともに高い製品を得ようとす
る場合は、鋼の結晶粒界を強化する目的でＢを40
±30ppmの範囲内で添加する。また、本発明を実
施するに際し、さらに優れた磁気特性、わけても
鉄損値の低い製品を得ようとする場合は、Alを
1.0％未満の範囲内で添加する。上記成分以外は、Feおよび不可避的不純物元
素である。（作用）次に本発明の製造方法について説明する。上記の適性範囲の成分からなる鋼は、転炉ある
いは電気炉など公知の方法で溶製され、連続鋳造
あるいは鋼塊に鋳造した後、分塊圧延によりスラ
ブとされる。次いでこのスラブを公知の方法で加
熱炉にて加熱あるいはホツト・チヤージし、ある
いは分塊圧延後、直送して熱間圧延し、例えば
1.5〜５mmの板厚とする。この熱延板を無焼鈍の
まま、あるいはノルマライジングのために例えば
900℃で２分間焼鈍した後、酸洗する。次いで１
回または途中に熱処理を含んで２回の公知の方法
で冷間圧延し、最終板厚、例えば0.30〜0.80mmと
する。しかる後、650℃以上、850℃未満の温度範囲で
低温再結晶焼鈍を行う。ここで焼鈍温度を上記の
範囲に限定したのは、650℃以下では所要の磁気
特性が得られず、また焼鈍後、鋼帯が平坦となら
ないためである。一方、焼鈍温度が850℃以上で
あると、結晶粒成長が急激に進行して機械特性が
劣化するので、安定して所要の機械特性と磁気特
性を同時に得るため上記の温度範囲とする。（実施例） (1) 実施例１表１に示す成分組成の各鋼を鋼塊に鋳造し、
1100℃に加熱して分塊圧延し、スラブとした。次
いで、1150℃に加熱してから熱間圧延を施して板
厚を2.0mmとした後、酸洗し、しかる後に冷間圧
延により最終板厚を0.5mmとした。続いて、この
冷延鋼帯を水素ガス10％を含む保護雰囲気下で
825℃で１分間焼鈍した。得られた各鋼帯の抗張
力と鉄損W_5/1000、磁束密度B₅₀を調査し、その結
果を同じく表１に示した。比較のため、従来の方
法で得られた鋼帯の各特性値を併記した。表１から明らかなように、Niを添加した本発
明鋼は、高い抗張力と低い鉄損値を示している。 (Industrial Application Field) The present invention relates to an electromagnetic steel sheet used as an iron core in the rotating part of a rotating machine, which has excellent mechanical properties and magnetic properties that can withstand stress during rotation or repeated stress during acceleration/deceleration, that is, iron loss. The present invention relates to a high tensile strength non-oriented electrical steel sheet having magnetic flux density without deterioration. (Prior Art) In recent years, with the development of electronics, the functions of drive systems for rotating machines have become more sophisticated, and various rotational drive controls have become possible. That is, by controlling the frequency of the drive power source, there has been an increase in the number of rotating machines that are capable of variable speed operation and high speed operation at higher frequencies. On the other hand, with the development of mechatronics,
The demand for faster rotating machines is increasing, and while high-speed rotating machines have traditionally been limited to relatively small capacities, this trend is expanding to the field of medium- and large-sized rotating machines. In order to realize such a high-speed rotating machine, the rotor must have a structure that can withstand high-speed rotation. Generally, the centrifugal force that acts on a rotating object is proportional to the radius of rotation, and increases in proportion to the square of the rotational speed, so in medium to large high-speed rotating machines, the force acting on the rotor is 60 kg/mm ² may exceed. Also,
In the case of ultra-large rotating machines, even if the rotation speed is relatively low, the diameter of the rotor is large, resulting in a weight loss of 60Kg/mm ²
In some cases, the above stress may be applied, and the rotor must be made of a material with high tensile strength. Furthermore, since acceleration and deceleration are frequently performed in rotating machines that require variable speed operation, the material must not only have high tensile strength, but also a high limit stress (fatigue limit) that can cause fatigue failure under repeated stress. No. Normally, laminated non-oriented electrical steel plates are used for the rotor of rotating machines, but there are cases where the above-mentioned rotating machine cannot satisfy the required mechanical strength, and in that case, solid cast steel rotating plates are used. Children are being employed. However, since the rotor of a rotating machine utilizes electromagnetic phenomena, its material is required to have excellent magnetic properties as well as the mechanical properties mentioned above. Of the magnetic properties required of rotor core materials, the most important are iron loss and magnetic flux density.
The main iron loss that occurs in the rotor is ripple loss that occurs on the surface of the rotor core due to high-frequency magnetic flux, and its frequency f _R is expressed as follows. f _R =2・f ₀・M/P where f ₀ : Frequency of driving power source M : Number of teeth of stator core P : Number of magnetic poles of rotating machine If we consider the case of a two-pole rotating machine where the frequency is approximately doubled, the frequency of the ripple magnetic flux will be in the range of 1 to 10 kHz. Therefore, it is desirable that such a rotor core material has a small iron loss in the above frequency range. However, since the solid cast steel rotor mentioned above is a one-piece piece, the eddy current loss becomes extremely large in the high frequency range, making it difficult to use as a rotating machine compared to a rotor made of laminated electromagnetic steel sheets. It is said that the efficiency is several percent lower. This is another important magnetic property. If the magnetic flux density of the rotor core material is low, the excitation ampere turns must be increased to flow the necessary magnetic flux through the rotor to generate the required torque.
This leads to an increase in copper loss in the excitation coil, resulting in a decrease in the overall efficiency of the rotating machine. That is,
Replacing a rotor made of solid cast steel with a rotor made of laminated materials with excellent mechanical properties and iron loss will definitely reduce iron loss, but if the magnetic flux density of that material is low, copper loss will increase. In some cases, the reduction in iron loss may be offset and efficiency may not improve. In this way, the rotor core material of such a rotating machine satisfies the following requirements: mechanically, it has high tensile strength and fatigue strength, and magnetically, it has low iron loss at high frequencies and high magnetic flux density. It has to be something. Methods commonly used in the field of cold-rolled steel sheets to increase the mechanical strength of steel sheets include solid solution hardening, precipitation hardening, hardening by grain refinement, and hardening by transformed structure. Strength and excellent magnetic properties such as low iron loss and high magnetic flux density are in a contradictory relationship, and it has been difficult to satisfy both at the same time. As a known technique, a method has been proposed, for example, as described in JP-A-60-238421, in which the Si content is increased to 3.5 to 7.0% and an element with high solid solution hardening is added to increase the tensile strength. However, since this method is highly dependent on the Si content,
100 when rolling from hot-rolled sheet to final cold-rolled thickness
The drawback was that warm rolling at ~600°C was required.
Furthermore, there was a major problem in that the magnetic flux density of the steel sheet obtained by this technique was extremely low, with a _B50 of 1.56 to 1.61T. Furthermore, in JP-A No. 61-9520, molten steel with increased Si content and addition of elements with high solid solution hardening is made into a steel strip by rapid solidification, which is then cold- or hot-rolled and then annealed. A method has been proposed for producing a high tensile strength non-oriented electrical steel sheet with high tensile strength and low iron loss. According to this technology,
Even if the Si content is increased, the rapid solidification method is used, so the constraints caused by material embrittlement as in the conventional rolling manufacturing method are alleviated. However, as with the previous technology, in order to obtain a high tensile strength of 70 Kg/mm ² or more, Si
The content must be increased to 4-4.5%, and the magnetic flux density
The problem was that the _B50 was very low. On the other hand, as proposed in Japanese Patent Application Laid-Open No. 55-65349, there is a technology for manufacturing sendust-based magnetic materials with extremely high hardness and high magnetic permeability, but these materials are mainly used for magnetic It is used for stationary devices such as heads or small high-frequency transformers. The rotor core of a rotating machine, which is the object of the present invention, is usually processed by punching and then laminated and bundled. In the actual operating condition of a rotating machine, the rotation and
Subject to repeated stress due to stopping, acceleration and deceleration. Therefore, such a rotor core material must be free from cracking during punching and must have high breaking strength against repeated stress. Sendust-based materials have high mechanical strength and excellent wear resistance, but on the other hand, they are extremely brittle.
From the above point of view, it could not be used for rotating machines. (Problems to be Solved by the Invention) The purpose of the present invention is to provide high tensile strength for rotating machines with excellent mechanical and magnetic properties that can be manufactured on an industrial scale using conventional rolling technology without using rapid solidification methods. The present invention aims to provide a non-oriented electrical steel sheet and a method for manufacturing the same. (Means for solving the problems) The gist of the present invention is as follows. (1) By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%,
Contains Ni: 0.3% or more and less than 10%, with the balance consisting of Fe and unavoidable impurities, tensile strength TS≧65
Kg/mm ² , and high frequency iron loss W _5/1000 ≦50W/Kg,
A high tensile strength non-oriented electrical steel sheet for rotating machines that has excellent mechanical and magnetic properties with a magnetic flux density B ₅₀ ≧1.65T. (2) By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, Ni
and Mn in the range of 0.3%≦Ni+Mn<10%, with the balance consisting of Fe and unavoidable impurities, tensile strength TS≧65Kg/mm ² and high frequency iron loss.
High tensile strength non-oriented electrical steel sheet for rotating machines with excellent mechanical and magnetic properties of W _5/1000 ≦50W/Kg and magnetic flux density B ₅₀ ≧1.65T. (3) By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, Ni
and Mn within the range of 0.3%≦Ni+Mn<10%, further Al: less than 1.0% and B: 40±
Tensile strength TS ≧ 65Kg/mm ² , containing any one of 30ppm and the remainder consisting of Fe and unavoidable impurities.
and high frequency iron loss W _5/1000 ≦50W/Kg, magnetic flux density
High tensile strength non-oriented electrical steel sheet for rotating machines with excellent mechanical and magnetic properties of B ₅₀ ≧1.65T. (4) By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%,
A steel containing Ni: 0.3% or more and less than 10%, the balance consisting of Fe and unavoidable impurities, is made into a steel ingot by continuous casting or injected into a mold, and this is bloomed into a slab, Next, hot rolled to make a hot rolled plate, either as it is or after hot rolled plate annealing, pickling, cold rolling to final plate thickness, 650
A method for manufacturing a high tensile strength non-oriented electrical steel sheet for rotating machines, characterized by low temperature recrystallization annealing in a temperature range of ℃ or higher and lower than 850℃. (5) By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, Ni
A steel containing Mn and Mn in the range of 0.3%≦Ni+Mn<10%, with the balance consisting of Fe and unavoidable impurities is made into a steel ingot by continuous casting or injected into a mold, and this is then bloomed and rolled. The slab is then hot-rolled to make a hot-rolled plate, either as it is or after hot-rolled plate annealing, pickled, cold-rolled to the final thickness, and then heated to a temperature of 650°C or more and less than 850°C. A method for manufacturing a high tensile strength non-oriented electrical steel sheet for rotating machines, characterized by low temperature recrystallization annealing in a temperature range. (6) By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, Ni
and Mn within the range of 0.3%≦Ni+Mn<10%, and further Al: less than 1.0 and B: 40±
A steel containing 30 ppm of any one of the above, with the remainder being Fe and unavoidable impurities, is made into a steel ingot by continuous casting or injected into a mold, which is then bloomed into a slab, and then hot rolled. The hot-rolled sheet is made into a hot-rolled sheet, either as is or after hot-rolled sheet annealing, pickled, cold-rolled to the final thickness, and then low-temperature recrystallization annealed at a temperature range of 650℃ or higher and lower than 850℃. A method for producing a high tensile strength non-oriented electrical steel sheet for rotating machines, characterized by: Another gist is that steel having the above components is made into a slab by continuous casting or steel ingot-blubber rolling, then hot rolled, left unannealed or after annealing, pickled, and cold rolled. After the final plate thickness is achieved, low-temperature recrystallization is performed at a temperature range of 650°C or higher and lower than 850°C. This invention will be explained in detail below. First, the reason why the components were limited to the above ranges will be explained. Si: 2.0% or more, less than 3.5% Si increases the specific resistance of steel and reduces overcurrent, so it is the most effective element for reducing iron loss.
At the same time, Si is an effective element for increasing tensile strength, but its effect is small if the amount added is less than 2%. On the other hand, as mentioned above, Si makes steel brittle and lowers the magnetic flux density of the product. Therefore, in the present invention, the Si content is set to less than 3.5% in order to enable production on an industrial scale using conventional rolling techniques and to ensure high magnetic flux density. C: 0.008% or less C increases the strength of steel, but on the other hand, iron loss deteriorates rapidly with respect to C content, so it is limited to 0.008% or less. P: 0.03% or more, less than 0.2% P is an element that has a very large effect of increasing tensile strength, but if it is less than 0.03%, it has almost no effect. On the other hand, P segregates at grain boundaries and embrittles slabs, hot-rolled sheets, and cold-rolled sheets. Therefore, continuous casting on an industrial scale
0.2% to enable hot rolling and cold rolling
less than Mn, Ni: 0.3%≦Mn+Ni<10% Both Mn and Ni have a relatively small adverse effect on the magnetic properties of the non-oriented electrical steel sheet, and have a large effect on increasing the tensile strength of the steel through solid solution hardening. Since Mn increases the tensile strength and specific resistance of steel, it is advantageous in reducing iron loss in the high frequency range of the product. Ni is an element that has a relatively small adverse effect on the magnetic properties of non-oriented electrical steel sheets and has a large effect of increasing the tensile strength without impairing the toughness of the steel. When Ni is added alone, 0.3
If the amount is less than %, no effect can be achieved. On the other hand, if it is added in an amount of 10% or more, the magnetic properties of the non-oriented electrical steel sheet, especially the magnetic flux density, will be reduced. In the present invention, as shown in the examples,
By adding Mn and Ni in combination, it is possible to obtain a non-oriented electrical steel sheet with high mechanical properties, particularly high tensile strength, and excellent magnetic properties. Even in the case of combined addition, the total amount of Ni and Mn is 0.3%
If the amount is less than that, the effect cannot be expressed. on the other hand,
If it is added in an amount of 10% or more, the magnetic properties of the non-oriented electrical steel sheet, especially the magnetic flux density, will be reduced, making it impossible to obtain a non-oriented electrical steel sheet having a magnetic flux density of 1.65 T or more, which is the technical problem of the present invention. Each of the above-mentioned elements generally makes steel brittle, so if you are trying to obtain a product with high tensile strength and toughness, add 40% B to strengthen the grain boundaries of the steel.
Add within the range of ±30ppm. In addition, when implementing the present invention, if you want to obtain a product with even better magnetic properties, especially a lower iron loss value, Al may be used.
Add within the range of less than 1.0%. Components other than the above are Fe and inevitable impurity elements. (Function) Next, the manufacturing method of the present invention will be explained. Steel having the above-mentioned suitable range of components is melted by a known method such as a converter or an electric furnace, continuously cast or cast into a steel ingot, and then made into a slab by blooming. Next, this slab is heated or hot-charged in a heating furnace by a known method, or after blooming, it is sent directly and hot-rolled, e.g.
The plate thickness shall be 1.5 to 5 mm. This hot-rolled sheet can be left unannealed or for normalizing, for example.
After annealing at 900°C for 2 minutes, pickling is performed. then 1
Cold rolling is carried out by a known method twice or twice, including heat treatment, to give a final thickness of, for example, 0.30 to 0.80 mm. After that, low-temperature recrystallization annealing is performed at a temperature range of 650°C or higher and lower than 850°C. The reason why the annealing temperature is limited to the above range is that the required magnetic properties cannot be obtained below 650° C., and the steel strip does not become flat after annealing. On the other hand, if the annealing temperature is 850°C or higher, crystal grain growth will proceed rapidly and mechanical properties will deteriorate, so the above temperature range is set in order to stably obtain the required mechanical properties and magnetic properties at the same time. (Example) (1) Example 1 Each steel having the composition shown in Table 1 was cast into a steel ingot,
It was heated to 1100°C and bloomed to form a slab. Next, it was heated to 1150°C and hot rolled to a plate thickness of 2.0 mm, followed by pickling, and then cold rolled to a final plate thickness of 0.5 mm. This cold-rolled steel strip is then subjected to a protective atmosphere containing 10% hydrogen gas.
Annealed at 825°C for 1 minute. The tensile strength, iron loss W _5/1000 , and magnetic flux density B ₅₀ of each of the obtained steel strips were investigated, and the results are also shown in Table 1. For comparison, each characteristic value of the steel strip obtained by the conventional method is also listed. As is clear from Table 1, the steel of the present invention to which Ni is added exhibits high tensile strength and low iron loss values.

【表】 (2) 実施例２表２に示す成分組成の各鋼を連続鋳造してスラ
ブとなし、1200℃に加熱してから熱間圧延を施し
て板厚2.8mmの熱延板を得た。この熱延板を920℃
で１分間焼鈍した後、酸洗し、次いで冷間圧延し
て最終板厚を0.7mmとした。この冷延鋼帯を725℃
で20秒間焼鈍した。得られた各鋼帯の抗張力と鉄
損W_5/1000、磁束密度B₅₀を同じく表２に示した。表２から明らかなように、熱延板焼鈍を施して
得られる本発明の製品は、70Kg／mm²近くの高い抗
張力と低い鉄損値を有している。[Table] (2) Example 2 Each steel having the composition shown in Table 2 was continuously cast into a slab, heated to 1200°C, and then hot rolled to obtain a hot rolled plate with a thickness of 2.8 mm. Ta. This hot-rolled plate is heated to 920℃
After annealing for 1 minute, the material was pickled and then cold rolled to a final thickness of 0.7 mm. This cold-rolled steel strip is heated to 725℃
Annealed for 20 seconds. Table 2 also shows the tensile strength, iron loss W _5/1000 , and magnetic flux density B ₅₀ of each steel strip obtained. As is clear from Table 2, the product of the present invention obtained by annealing hot-rolled sheets has a high tensile strength of nearly 70 Kg/mm ² and a low iron loss value.

【表】 (3) 実施例３表３に示す成分組成の各鋼を連続鋳造して得ら
れたスラブを、そのまま直送して熱間圧延を施し
て板厚2.8mmの熱延板とした。この熱延板を焼鈍
せずに酸洗のみ行い、次いで冷間圧延して最終板
厚を0.5mmとした。この冷延鋼帯を700℃で30秒間
焼鈍した。得られた各鋼帯の抗張力と鉄損
W_5/1000、磁束密度B₅₀を同じく表３に示した。表３から明らかなように、本発明によつて得ら
れる無方向性電磁鋼板は、50W／Kg以下の低い鉄
損値を有するとともに、極めて高い抗張力を有す
る。[Table] (3) Example 3 Slabs obtained by continuous casting of each steel having the composition shown in Table 3 were directly delivered as they were and hot rolled to form hot rolled plates with a thickness of 2.8 mm. This hot-rolled sheet was only pickled without annealing, and then cold-rolled to a final sheet thickness of 0.5 mm. This cold rolled steel strip was annealed at 700°C for 30 seconds. Tensile strength and iron loss of each steel strip obtained
W _5/1000 and magnetic flux density B ₅₀ are also shown in Table 3. As is clear from Table 3, the non-oriented electrical steel sheet obtained by the present invention has a low iron loss value of 50 W/Kg or less and an extremely high tensile strength.

【表】（発明の効果）以上のように、本発明により、高い抗張力を有
し、かつ鉄損が低く、磁束密度が高いことを同時
に併せ持つ高抗張力無方向性電磁鋼板が得られ、
回転機の中・大型化による高効率化に伴い、その
回転子用鉄心材料として用いられる高抗張力無方
向性電磁鋼板に対する要請に十分応えることがで
き、その工業的効果は非常に大きい。[Table] (Effects of the invention) As described above, the present invention provides a high tensile strength non-oriented electrical steel sheet that has high tensile strength, low core loss, and high magnetic flux density.
With the increasing efficiency of medium- and large-sized rotating machines, we can fully meet the demand for high tensile strength non-oriented electrical steel sheets used as core materials for rotors, and the industrial effect is extremely large.

Claims

[Claims] 1. By weight, Si: 2.0% or more and less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, Ni:
Tensile strength TS≧65Kg/mm ² , containing 0.3% or more and less than 10%, with the balance consisting of Fe and unavoidable impurities.
and high frequency iron loss W _5/1000 ≦50W/Kg, magnetic flux density B ₅₀
High tensile strength non-oriented electrical steel sheet for rotating machines with excellent mechanical and magnetic properties of ≧1.65T. 2 By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, contains Ni and Mn within the range of 0.3%≦Ni+Mn<10%, the balance consists of Fe and unavoidable impurities, tensile strength TS≧65Kg/mm ² , and High frequency iron loss W _5/1000 ≦
High tensile strength non-oriented electrical steel sheet for rotating machines with excellent mechanical and magnetic properties of 50W/Kg and magnetic flux density B ₅₀ ≧1.65T. 3 By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, contains Ni and Mn within the range of 0.3%≦Ni+Mn<10%, and Al: less than 1.0% and B: 40±30ppm
Contains any one of the above, with the balance consisting of Fe and unavoidable impurities, tensile strength TS≧65Kg/mm ² , high-frequency iron loss W _5/1000 ≦50W/Kg, and magnetic flux density B ₅₀ ≧1.65T
High tensile strength non-oriented electrical steel sheet for rotating machines with excellent mechanical and magnetic properties. 4 By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, Ni:
A steel containing 0.3% or more but less than 10%, with the balance consisting of Fe and unavoidable impurities, is made into a steel ingot by continuous casting or injected into a mold, which is then bloomed into a slab, and then heated. After being rolled into a hot-rolled plate, either as it is or after hot-rolled plate annealing, pickling, cold rolling to the final thickness, and then low-temperature recrystallization in a temperature range of 650℃ or higher and lower than 850℃. A method for producing a high tensile strength non-oriented electrical steel sheet for rotating machines, which comprises annealing. 5 By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, steel containing Ni and Mn within the range of 0.3%≦Ni+Mn<10%, the balance consisting of Fe and inevitable impurities,
A steel ingot is made by continuous casting or injected into a mold,
This is bloomed into a slab, then hot-rolled into a hot-rolled plate, either as it is or after hot-rolled plate annealing, pickled, and cold-rolled to the final thickness.
A method for producing a high tensile strength non-oriented electrical steel sheet for rotating machines, which comprises performing low-temperature recrystallization annealing in a temperature range of 650°C or higher and lower than 850°C. 6 By weight, Si: 2.0% or more, less than 3.5%, C:
0.008% or less, P: 0.03% or more, less than 0.2%, contains Ni and Mn within the range of 0.3%≦Ni+Mn<10%, and Al: less than 1.0% and B: 40±30ppm
A steel containing any one of the following, with the remainder being Fe and unavoidable impurities, is made into a steel ingot by continuous casting or by pouring it into a mold, which is then bloomed into a slab, and then hot rolled. The hot-rolled sheet is made into a hot-rolled sheet, either as it is or after hot-rolled sheet annealing, pickled, cold-rolled to the final thickness, and then subjected to low-temperature recrystallization annealing at a temperature range of 650℃ or higher and lower than 850℃. A method for manufacturing a high tensile strength non-oriented electrical steel sheet for rotating machines, characterized by: