JP6414172B2 - Non-oriented electrical steel sheet and manufacturing method thereof - Google Patents
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Description
本発明は、モータやトランスの鉄心など、電気材料として用いるのに好適な磁気特性に優れた無方向性電磁鋼板に関するものである。 The present invention relates to a non-oriented electrical steel sheet having excellent magnetic properties suitable for use as an electrical material such as a motor or a transformer iron core.
磁気特性に優れる無方向性電磁鋼板は主に、電気自動車の駆動用モータや、家電機器のモータとして用いられ、それらのエネルギ使用効率向上のために低鉄損が要求され、また、モータの小型化のために高磁束密度が要求されている。 Non-oriented electrical steel sheets with excellent magnetic properties are mainly used as electric motor drive motors and home appliance motors. Low iron loss is required to improve the energy efficiency of these products. High magnetic flux density is required in order to make it easier.
このような要求に対し、磁気特性向上に不利な集合組織である(111)面方位を低減するために、冷間圧延前の粒径を粗大化させたり、熱延板を可能な限り薄くして冷延率を低減させたりする手法がとられてきた。 In response to these requirements, in order to reduce the (111) plane orientation, which is a texture that is disadvantageous for improving magnetic properties, the grain size before cold rolling is increased, and the hot-rolled sheet is made as thin as possible. Thus, a technique for reducing the cold rolling rate has been taken.
また、鋼中の不純物を限りなく低減させ、析出物形成によるヒステリシス損の増大を抑制する試みがなされてきた。 In addition, attempts have been made to reduce impurities in steel as much as possible and suppress an increase in hysteresis loss due to precipitate formation.
さらに、低圧雰囲気での高温焼鈍によって、極めて高い磁束密度を得る技術が知られている。これは、低圧雰囲気では、表面エネルギの低い(100)面方位や(110)面方位を有する結晶粒が、より表面エネルギの高い他の方位を有する結晶粒を蚕食することによって成長する機構を利用したものである。この手法はSiやAl添加などの方法に頼らないため、合金コストのトレンドに左右されることなく良好な磁性を有する無方向性電磁鋼板を生産できるといった利点がある。特に、(100)面方位は、圧延面内に磁化容易軸が２つ存在するため、磁化容易軸が１つである(110)面方位と比較して、面内方向での平均的な磁束密度がより高くなる方位であって、無方向性電磁鋼板に理想的な結晶方位であると考えられている。 Furthermore, a technique for obtaining an extremely high magnetic flux density by high-temperature annealing in a low-pressure atmosphere is known. This is because a low-pressure atmosphere uses a mechanism in which a crystal grain having a low (100) or (110) plane orientation grows by engulfing a crystal grain having another orientation with a higher surface energy. It is a thing. Since this method does not depend on methods such as Si or Al addition, there is an advantage that a non-oriented electrical steel sheet having good magnetism can be produced without being influenced by the trend of alloy costs. In particular, since the (100) plane orientation has two easy magnetization axes in the rolling surface, the average magnetic flux in the in-plane direction compared to the (110) plane orientation with one easy magnetization axis. It is an orientation with higher density, and is considered to be an ideal crystal orientation for a non-oriented electrical steel sheet.
もう一つの重要な磁気特性である鉄損は、便宜的に、励磁周波数に依存しないヒステリシス損と、励磁周波数に依存する渦電流損とに分離して考えることがある。近年の無方向性電磁鋼板においては、渦電流損の低減がより求められる傾向にある。これは、モータの回転数を増大させるため、高周波励磁条件下で無方向性電磁鋼板が使用されることが多くなり、この場合には、全鉄損に占める渦電流損の割合が増大するためである。 For the sake of convenience, iron loss, which is another important magnetic characteristic, may be considered separately as hysteresis loss that does not depend on the excitation frequency and eddy current loss that depends on the excitation frequency. In recent non-oriented electrical steel sheets, reduction of eddy current loss tends to be more demanded. This increases the number of rotations of the motor, and non-oriented electrical steel sheets are often used under high-frequency excitation conditions. In this case, the ratio of eddy current loss to total iron loss increases. It is.
例えば、特許文献１に示されるように、従来材においては、真空雰囲気での焼鈍技術によって、非常に良好な磁束密度Ｂ50および鉄損Ｗ15/100が得られていたが、高周波域でも優れた鉄損を得ることが困難であった。 For example, as shown in Patent Document 1, in the conventional material, a very good magnetic flux density B 50 and iron loss W 15/100 have been obtained by the annealing technique in a vacuum atmosphere. It was difficult to obtain iron loss.
本発明者らが調査した結果、従来材の組織は、磁束密度の向上に有利な(100)集合組織が形成されているものの、圧延方向（以下、「Ｌ方向」とする。）、圧延方向に対して直角の方向（以下、「Ｃ方向」とする。）、および圧延方向に対して45°の方向（以下、「Ｄ方向」とする。）における磁束密度Ｂ50の差が大きく、極端な例では、Ｌ方向が1.65Ｔである一方で、Ｄ方向で1.82Ｔとなることがあった。これは、磁化容易軸がある特定の方向（上記の例ではＤ方向あるいはそれに近い方向）にのみ向いてしまっているためと考えられる。このような異方性が形成されると、磁気特性の劣位な方向において、鉄損が極めて高くなってしまう。さらに、従来材の組織は、結晶粒径のばらつきが非常に大きく、例えば、数mm径から最大で圧延方向に40mmに至る径の超粗大結晶粒が分散していた。一般的に、鋼板の鉄損の一部である渦電流損は、粗大粒であるほど増大する。これは、渦電流損に影響をおよぼす、結晶粒内の磁区幅が増大するためであると考えられる。このため、粗大な結晶粒を有する鋼板は、高周波鉄損での鉄損優位性を示すのが困難となるのが一般的である。 As a result of investigations by the present inventors, the structure of the conventional material is formed in the rolling direction (hereinafter referred to as “L direction”) and the rolling direction, although the (100) texture that is advantageous for improving the magnetic flux density is formed. Difference in magnetic flux density B 50 in a direction perpendicular to the direction (hereinafter referred to as “C direction”) and 45 ° to the rolling direction (hereinafter referred to as “D direction”) is extremely large. In an example, the L direction was 1.65T, while the D direction was 1.82T. This is presumably because the easy magnetization axis is oriented only in a certain direction (in the above example, the D direction or a direction close thereto). When such anisotropy is formed, the iron loss becomes extremely high in the direction of inferior magnetic properties. Furthermore, the structure of the conventional material has a very large variation in crystal grain size, for example, ultra coarse crystal grains having a diameter ranging from a few mm to a maximum of 40 mm in the rolling direction are dispersed. Generally, the eddy current loss which is a part of the iron loss of a steel plate increases as the grain size increases. This is considered to be due to an increase in the magnetic domain width in the crystal grains, which affects the eddy current loss. For this reason, it is generally difficult for a steel sheet having coarse crystal grains to exhibit an iron loss advantage in high-frequency iron loss.
本発明は、上記の課題に鑑み、磁束密度が高く、さらに低周波鉄損のみならず、高周波鉄損も低い無方向性電磁鋼板を提供することを目的とする。 In view of the above problems, an object of the present invention is to provide a non-oriented electrical steel sheet having a high magnetic flux density and low low-frequency iron loss as well as low-frequency iron loss.
本発明者らは、上記した低圧雰囲気での焼鈍後に認められた極めて粗大な結晶粒が出現した原因を調査した結果、低圧雰囲気での焼鈍前に鋼板表層に析出するSi酸化物の量が多く存在するほど、焼鈍後に粗大な結晶粒が生成しやすいことを見出した。さらに、本発明者らは、(100)面の磁化容易軸の分布を、冷間圧延条件によって制御できることを見出した。 As a result of investigating the cause of the appearance of extremely coarse crystal grains observed after annealing in the low-pressure atmosphere, the present inventors have found that the amount of Si oxide precipitated on the steel sheet surface layer before annealing in the low-pressure atmosphere is large. It has been found that the more it is present, the easier it is to produce coarse crystal grains after annealing. Furthermore, the present inventors have found that the distribution of easy axes of the (100) plane can be controlled by cold rolling conditions.
以下、本発明を導くに至った実験結果について説明する。
図１は、Ｌ方向:280mm×Ｃ方向:30mm幅の鋼を試料として、電子線マイクロアナライザー（EPMA）解析によって測定した表面の酸素カウント値と、鋼中のＳ量と、焼鈍後の粗大結晶粒の存在の有無との関係を示す。焼鈍条件は、均熱温度1200℃、均熱時間60分、0.05Paの低圧雰囲気とした。圧延方向に20mm以上の粒径を有する結晶粒を粗大結晶粒とし、その存在の有無については、有の場合は×、無の場合は○で示した。
Hereinafter, experimental results that led to the present invention will be described.
Fig. 1 shows the surface oxygen count value measured by electron beam microanalyzer (EPMA) analysis, the amount of S in the steel, and the coarse crystal after annealing, using a steel of L direction: 280 mm × C direction: 30 mm width as a sample. The relationship with the presence or absence of grains is shown. The annealing conditions were a soaking temperature of 1200 ° C., a soaking time of 60 minutes, and a low pressure atmosphere of 0.05 Pa. The crystal grains having a grain size of 20 mm or more in the rolling direction were coarse crystal grains, and the presence / absence thereof was indicated by “X” when present and “◯” when absent.
鋼中のMnは0.01％、Ｐは0.006％であった。
EPMA解析は、EPMA-1600シリーズ(島津製作所製)の装置によって、電子線の加速電圧は15kV、スポットサイズは20μm、１点のサンプリング時間は70msecの条件下で行った。ここで、酸素カウント値とは、O-Kα線カウント値であり、サンプリング時間を70msecとしたときの波長分散型検出器による総カウント数を意味する。
Mn in the steel was 0.01% and P was 0.006%.
The EPMA analysis was performed using an EPMA-1600 series device (manufactured by Shimadzu Corporation) under the conditions of an electron beam acceleration voltage of 15 kV, a spot size of 20 μm, and a sampling time of 70 msec. Here, the oxygen count value is an O-Kα ray count value, and means the total count number by the wavelength dispersion detector when the sampling time is 70 msec.
酸素カウント値の測定領域は、5mm×5mmとし、その中で、スポット間隔を2μmとして、250×250の点でサンプリングを行い、その平均値を求めた。この結果、酸素カウント値が250以下になると、粗大粒の出現を抑制することが可能であることが明らかとなった。また、酸素カウント値は、鋼中のＳ量との関連性を示し、鋼中のＳ量が低いほど、酸素カウント値が低くなる傾向を示した。さらに、板厚断面観察の結果、粒界にも同様のSi系酸化物が存在し、鋼中のＳ量が低いほどSi系酸化物が少なくなることが確認された。また、酸素以外の元素分析の結果から、この酸化物は、Si系の酸化物であることが判明した。 The measurement area of the oxygen count value was 5 mm × 5 mm, in which the spot interval was 2 μm, sampling was performed at 250 × 250 points, and the average value was obtained. As a result, it has been clarified that when the oxygen count value is 250 or less, the appearance of coarse particles can be suppressed. Further, the oxygen count value showed a relationship with the amount of S in steel, and the oxygen count value tended to be lower as the amount of S in steel was lower. Furthermore, as a result of plate thickness cross-sectional observation, it was confirmed that similar Si-based oxides exist at the grain boundaries, and that the Si-based oxides decrease as the S content in the steel decreases. The results of elemental analysis other than oxygen revealed that this oxide was a Si-based oxide.
さらに、本発明者らは、鋼中のＳ量が十分低い場合であっても、鋼中のＰ量が多い場合には、最終の低圧雰囲気での焼鈍後に所望の結晶組織が得られないことを見出した。これは、Ｐが熱延板および続く工程で得られる鋼板のフェライト組織を微細化し、表面エネルギを駆動力とした粒成長を起こしやすい、板厚貫通粒の形成を抑制するためと考えている。また、Ｓ量も同様にフェライト粒の大きさに影響を与えることから、Ｓ量が低い場合には許容されるＰ量の上限は高くなると考え、所望する組織を得るために必要な鋼組成として、鋼中のＳ量とＰ量の積の値に着目した。図２に、鋼中のＳ量と、鋼中のＳ量とＰ量の積と、所望組織の達成有無を示す。鋼板の表層における(100)面の傾きが圧延面に対して3°以内である結晶粒の総面積率が70％以上であって、かつ該結晶粒の前記鋼板の圧延方向における平均粒径が10mm以下である組織が得られた場合を○、得られなかった場合を×で示す。この結果から、鋼中のＳ量(ppm)×Ｐ量(ppm)が400未満であれば、所望の組織が得られる傾向が認められた。 Furthermore, the present inventors cannot obtain a desired crystal structure after annealing in the final low-pressure atmosphere if the amount of P in the steel is large even when the amount of S in the steel is sufficiently low. I found. This is because P refines the ferrite structure of the hot-rolled sheet and the steel sheet obtained in the subsequent process, and suppresses the formation of sheet-thickness through grains that easily cause grain growth using surface energy as a driving force. In addition, since the amount of S similarly affects the size of the ferrite grains, the upper limit of the allowable amount of P is increased when the amount of S is low, and as a steel composition necessary for obtaining a desired structure. Attention was paid to the product of the amount of S and the amount of P in steel. FIG. 2 shows the amount of S in steel, the product of the amount of S and P in steel, and whether or not the desired structure has been achieved. The total area ratio of the crystal grains in which the inclination of the (100) plane in the surface layer of the steel sheet is within 3 ° with respect to the rolling surface is 70% or more, and the average grain diameter of the crystal grains in the rolling direction of the steel sheet is A case where a structure of 10 mm or less is obtained is indicated by ◯, and a case where the structure is not obtained is indicated by ×. From this result, when the amount of S in the steel (ppm) × P amount (ppm) was less than 400, a tendency to obtain a desired structure was recognized.
低圧雰囲気での焼鈍前の鋼中の表面Si酸化物量が多い場合に、粗大粒を生成する異常粒成長が助長されたことの原因については、不明な部分が多いが、低圧雰囲気での焼鈍後には、表層酸化物はカウント数100以下まで減少したことから、SiＯ2などの析出物が、低圧雰囲気での焼鈍初期にインヒビタとして機能し、それらが減少（おそらくは鋼中にわずかに含有されるＣと反応して低圧雰囲気中に分解）するにつれて異常粒成長が発現したのではないかと推定している。また、鋼中のＰ量が多い場合には、結晶粒が小さくなる傾向が認められたことから、焼鈍中に粒成長が過度に抑制され、表面エネルギを駆動力とした(100)面方位の結晶粒の粒成長が抑制されたと考えられる。 There are many unclear reasons why abnormal grain growth that generates coarse grains is promoted when the amount of surface Si oxide in the steel before annealing in a low-pressure atmosphere is large, but after annealing in a low-pressure atmosphere Since the surface layer oxide was reduced to a count of 100 or less, precipitates such as SiO 2 functioned as inhibitors in the early stage of annealing in a low-pressure atmosphere, and they decreased (perhaps a slight amount of C contained in the steel). It is presumed that abnormal grain growth was developed as it decomposed in a low-pressure atmosphere. In addition, when the amount of P in the steel is large, the tendency of the crystal grains to become smaller was recognized, so that the grain growth was excessively suppressed during annealing, and the surface energy was used as the driving force in the (100) plane orientation. It is thought that the grain growth of the crystal grains was suppressed.
続いて、本発明者らは、以下の冷間圧延条件によって、Ｌ方向、Ｃ方向、およびＤ方向での磁束密度Ｂ50を均一化できることを見出した。鋼中に、Ｃを0.0008％、Siを3.00％、Mnを0.03％、Ｐを0.005％、Sを0.0004％および残部はFeおよび不可避的不純物を含有する熱延板を、表１に示す冷間圧延条件で、最終板厚0.1mmの最終焼鈍前の状態に仕上げた。また、中間焼鈍はいずれも950℃均熱時間2分Ar雰囲気中で行った。これを、窒素大気圧雰囲気から圧力0.5Paまで減圧した真空中で、1200℃3時間の均熱処理を行った。その後SST（単板磁気試験器）でＬ方向、Ｃ方向、Ｄ方向の磁束密度Ｂ50を測定し、その最大値と最小値の差をΔＢ50として求めた。ΔＢ50は、冷間圧延の回数が1回より2回、3回の方が小さくなる傾向であった。また、Ｎ−１回目の冷間圧延における圧延率は80％より高いか、あるいは、最終冷間圧延の圧延率が80％以上であると、ΔＢ50が0.10より大きくなった。最終焼鈍後の結晶粒は、最終冷間圧延した鋼板内に存在する結晶粒が、再結晶・粒成長過程において、選択的に成長したものと考えられる。従って、冷間圧延を適正化することによって、最終冷延板に磁化容易軸が様々な方向を向いた(100)面方位を有する結晶粒が多く残存し、さらに再結晶・粒成長中にこれらの結晶粒が優先的に成長できる冷延板の集合組織が形成されたものと推定している。 Subsequently, the present inventors have found that the magnetic flux density B 50 in the L direction, the C direction, and the D direction can be made uniform by the following cold rolling conditions. Table 1 shows hot rolled sheets containing 0.0008% C, 3.00% Si, 0.03% Mn, 0.005% P, 0.0004% S and the balance Fe and unavoidable impurities in steel. In the rolling conditions, the final plate thickness was 0.1 mm before final annealing. In addition, intermediate annealing was performed in an Ar atmosphere at 950 ° C. for 2 minutes. This was soaked at 1200 ° C. for 3 hours in a vacuum reduced from an atmospheric pressure of nitrogen to a pressure of 0.5 Pa. Thereafter, the magnetic flux density B 50 in the L direction, C direction, and D direction was measured with an SST (single plate magnetic tester), and the difference between the maximum value and the minimum value was determined as ΔB 50 . ΔB 50 tended to be smaller when the number of cold rolling operations was twice or three times than once. In addition, when the rolling rate in the N-1th cold rolling was higher than 80%, or when the rolling rate in the final cold rolling was 80% or more, ΔB 50 was larger than 0.10. It is considered that the crystal grains after the final annealing were selectively grown in the recrystallization / grain growth process by the crystal grains existing in the steel plate that was finally cold-rolled. Therefore, by optimizing the cold rolling, a large number of crystal grains having (100) plane orientation with the easy axis of magnetization oriented in various directions remain in the final cold rolled sheet, and these crystals are further grown during recrystallization and grain growth. It is presumed that a texture of cold-rolled plates that allows the crystal grains to grow preferentially was formed.
本発明は、上記の実験結果から導かれる、低圧雰囲気での焼鈍前の表面Si酸化物量（Ｓの含有量と相関関係がある）を低減させることによって粗大粒の生成が抑制され、また、ＳおよびＰ含有量を低減させることによって表面エネルギを駆動力とした粒成長が発現され、さらに、冷間圧延の適正化により、低圧雰囲気での最終焼鈍中に無方向性電磁鋼板の磁気特性に好ましい結晶方位の優先的な成長が促進可能である、との技術思想に基づき、その他の諸条件の適正化を合わせて完成させたものである。
本発明はかかる知見に基づきなされたもので、以下のような構成を有する。
According to the present invention, the formation of coarse particles is suppressed by reducing the amount of surface Si oxide (which has a correlation with the S content) before annealing in a low-pressure atmosphere, which is derived from the above experimental results. And by reducing the P content, grain growth with surface energy as the driving force is expressed, and by optimizing cold rolling, it is preferable for the magnetic properties of the non-oriented electrical steel sheet during final annealing in a low pressure atmosphere Based on the technical idea that preferential growth of crystal orientation can be promoted, it was completed by optimizing other conditions.
The present invention has been made based on such knowledge, and has the following configuration.
１．質量％で、
Ｃ:0.0050％以下、
Si:1.00％以上5.00％以下、
Ｐ:0.1000％以下、
Mn:2.00％以下
Ｓ:0.0009％以下および
Ca:0.0005％以下
を含有し、残部はFeおよび不可避的不純物からなる成分組成を有し、
鋼板の表層における(100)面の傾きが圧延面に対して3°以内である結晶粒の総面積率が70％以上であって、圧延方向、圧延方向に対して直角の方向、および圧延方向に対して45°の方向における磁束密度Ｂ50の最大値と最小値との差が0.10Ｔ未満であり、かつ該結晶粒の前記鋼板の圧延方向における平均粒径が10mm以下であることを特徴とする無方向性電磁鋼板。
1. % By mass
C: 0.0050% or less,
Si: 1.00% to 5.00%,
P: 0.1000% or less,
Mn: 2.00% or less S: 0.0009% or less
Ca: 0.0005% or less, the balance has a component composition consisting of Fe and inevitable impurities,
The total area ratio of crystal grains in which the inclination of the (100) plane in the surface layer of the steel sheet is within 3 ° with respect to the rolling surface is 70% or more, and the rolling direction, the direction perpendicular to the rolling direction, and the rolling direction The difference between the maximum value and the minimum value of the magnetic flux density B 50 in the direction of 45 ° is less than 0.10 T, and the average grain size of the crystal grains in the rolling direction of the steel sheet is 10 mm or less. Non-oriented electrical steel sheet.
２．前記成分組成は、さらに、
質量％で、
SbおよびSnのいずれか１種または２種を合計で0.030％以下、含有することを特徴とする、上記１に記載の無方向性電磁鋼板。
2. The component composition further includes:
% By mass
The non-oriented electrical steel sheet according to 1 above, which contains one or two of Sb and Sn in a total amount of 0.030% or less.
３．上記１または２に記載の成分組成を有する鋼素材を熱間圧延し、冷間圧延し、最終焼鈍を施す無方向性電磁鋼板の製造方法であって、
前記冷間圧延は、計Ｎ回（Ｎ＝2，3）行い、各冷間圧延の間には中間焼鈍を行い、
Ｎ−１回目の冷間圧延における圧延率は80％以下であり、かつ最終の冷間圧延率は40％以上80％未満であり、
前記最終焼鈍は、1.0Pa以下かつ1100℃以上の雰囲気で行うことを特徴とする無方向性電磁鋼板の製造方法。
3. A method for producing a non-oriented electrical steel sheet that hot-rolls a steel material having the component composition described in 1 or 2 above, cold-rolls, and performs final annealing,
The cold rolling is performed a total of N times (N = 2, 3), and intermediate annealing is performed between each cold rolling,
The rolling reduction in the (N-1) th cold rolling is 80% or less, and the final cold rolling reduction is 40% or more and less than 80%,
The method for producing a non-oriented electrical steel sheet, wherein the final annealing is performed in an atmosphere of 1.0 Pa or lower and 1100 ° C. or higher.
４．前記いずれかの冷間圧延前に、1050℃以上の非酸化性雰囲気で焼鈍を行うことを特徴とする、上記３に記載の無方向性電磁鋼板の製造方法。 4). 4. The method for producing a non-oriented electrical steel sheet according to 3 above, wherein annealing is performed in a non-oxidizing atmosphere at 1050 ° C. or higher before any of the cold rolling.
５．上記１または２に記載の成分組成を有する鋼素材を熱間圧延し、
該熱間圧延後の鋼板を冷間圧延して最終板厚とし、
該最終板厚を有する鋼板を、1.0Pa以下の低圧雰囲気で、1100℃以上の温度で焼鈍し、
前記鋼素材は、ＰとＳとの含有量（ppm）の積が400未満であり、
前記焼鈍に供される鋼板は、その表層の酸素量が、サンプリング時間を70msec、加速電圧を15kV、スポットサイズを20μｍとしたときの波長分散型検出器によるＯ-Kα線カウント値の総数で250カウント値以下であることを特徴とする無方向性電磁鋼板の製造方法。
5. Hot-rolling a steel material having the component composition described in 1 or 2 above,
Cold rolling the steel sheet after the hot rolling to the final thickness,
The steel sheet having the final thickness is annealed at a temperature of 1100 ° C. or higher in a low pressure atmosphere of 1.0 Pa or lower,
The steel material has a product of P and S content (ppm) of less than 400,
Steel sheet to be subjected to the annealing, oxygen content of the table layer, the sampling time 70 msec, the acceleration voltage 15kV, the total number of O-K [alpha line count value of the wavelength dispersive detector when the spot size and 20μm A method for producing a non-oriented electrical steel sheet, wherein the count value is 250 counts or less.
本発明によれば、磁束密度が高く、さらに低周波鉄損が低いのみならず、高周波鉄損も低い無方向性電磁鋼板を得ることができる。 According to the present invention, it is possible to obtain a non-oriented electrical steel sheet that has a high magnetic flux density, low low-frequency iron loss, and low high-frequency iron loss.
以下、本発明の一実施形態に係る無方向性電磁鋼板について説明する。まず、鋼の成分組成の限定理由について述べる。なお、本明細書において、各成分元素の含有量を表す「％」は、特に断らない限り「質量％」を意味する。 Hereinafter, a non-oriented electrical steel sheet according to an embodiment of the present invention will be described. First, the reasons for limiting the component composition of steel will be described. In the present specification, “%” representing the content of each component element means “% by mass” unless otherwise specified.
Ｃ：0.0050％以下
Ｃが高いと、磁気時効し、磁気特性を劣化させることから、0.0050％以下とする。より高温環境下での鋼板の使用に伴う磁気時効の抑制する観点や、過度にＣ含有量を低くすることによる製造コストの増大の観点から、さらに好ましい範囲は、0.0003％以上0.0030％以下である。また、鋼中にSiＯ２が存在する場合には、低圧雰囲気での焼鈍中に、
SiＯ２＋2Ｃ → Si＋2ＣＯ
と推定される反応によって脱炭が進むことから、Ｃが0.0030％から0.0050％の範囲であっても、最終的には磁気時効に悪影響を与えない0.0030％以下程度にすることができる。
C: 0.0050% or less When C is high, magnetic aging is performed and magnetic characteristics are deteriorated. From the viewpoint of suppressing the magnetic aging associated with the use of the steel sheet in a higher temperature environment and the viewpoint of increasing the manufacturing cost by excessively reducing the C content, a more preferable range is 0.0003% or more and 0.0030% or less. . Also, when SiO 2 is present in the steel, during annealing in a low pressure atmosphere,
SiO 2 + 2C → Si + 2CO
Therefore, even if C is in the range of 0.0030% to 0.0050%, it can be finally reduced to about 0.0030% or less which does not adversely affect magnetic aging.
Si:1.00％以上5.00％以下
Siは、比抵抗を増大する元素であり、渦電流損を改善させることが可能であるため、1.00％以上の添加は必須である。一方で、過度に添加すると、磁束密度を減少させるため、5.00％以下とする。より好ましい範囲は、1.50％以上4.00％以下である。
Si: 1.00% to 5.00%
Since Si is an element that increases the specific resistance and can improve eddy current loss, addition of 1.00% or more is essential. On the other hand, if excessively added, the magnetic flux density is decreased, so the content is made 5.00% or less. A more preferable range is 1.50% or more and 4.00% or less.
Mn:2.00％以下
Mnは、比抵抗を増大する元素であるが、過度に添加するとコストが増大するため2.00％以下にする。MnＳ生成によるフェライト粒の微細化を抑制するため、特に好ましくは、0.12％以下である。下限については製鋼段階での過度な脱Mnコストが生じないよう0.001％とするのが好ましい。これによって、MnＳの体積分率が減少し、インヒビタとしての粒成長抑制力が弱まり、低圧雰囲気での焼鈍中に(100)の面方位を有する結晶粒の異常粒成長が抑制され、安定的に＜001＞軸が圧延面内にランダムに分布した結晶粒群（(100)[0vw]ともいう）を優先成長させることが可能である。
Mn: 2.00% or less
Mn is an element that increases the specific resistance, but if added excessively, the cost increases, so it is made 2.00% or less. In order to suppress the refinement of ferrite grains due to MnS generation, the content is particularly preferably 0.12% or less. The lower limit is preferably 0.001% so as not to cause excessive de-Mn cost at the steel making stage. This reduces the volume fraction of MnS, weakens the inhibitory effect on grain growth as an inhibitor, and suppresses abnormal grain growth of crystal grains having a (100) orientation during annealing in a low-pressure atmosphere. It is possible to preferentially grow a crystal grain group (also referred to as (100) [0vw]) in which the <001> axis is randomly distributed in the rolling surface.
Ｐ:0.1000％以下
Ｐは、鋼板を高強度化し、打ち抜き性を改善させる効果があるが、一方で、鋼板を脆化させるため、上限を0.1000％とする。また、最終冷間圧延前に非酸化性雰囲気にて高温焼鈍してＳを純化させない場合には、Ｐの含有量は、Ｓ(ppm)×Ｐ(ppm)＜400を満たすようにする。
P: 0.1000% or less P has the effect of increasing the strength of the steel sheet and improving the punchability. On the other hand, the upper limit is made 0.1000% in order to embrittle the steel sheet. When S is not purified by high-temperature annealing in a non-oxidizing atmosphere before the final cold rolling, the P content is set to satisfy S (ppm) × P (ppm) <400.
Ｓ:0.0009％以下
Ｓは、MnＳを形成し、粒成長性を損なうだけでなく、表面酸化物の形成を促進するため、特に低減する必要がある。そのためには、0.0009％以下とする。より好ましくは、0.0007％以下とする。また、最終冷間圧延前に非酸化性雰囲気にて高温焼鈍してＳを純化させない場合には、Ｓの含有量は、Ｓ(ppm)×Ｐ(ppm)＜400を満たすようにする。
S: 0.0009% or less S forms MnS and not only impairs the grain growth but also promotes the formation of surface oxides, so it needs to be reduced particularly. For that purpose, it is 0.0009% or less. More preferably, it is 0.0007% or less. When S is not purified by high-temperature annealing in a non-oxidizing atmosphere before the final cold rolling, the S content is set to satisfy S (ppm) × P (ppm) <400.
Ca:0.0005％以下
Caは、脱酸や固溶Ｓを析出するために添加され、これらの析出物が十分粗大に析出すれば、固溶Ｓ低減によって、粒成長抑制効果を減じる効果が認められるものの、析出物が不可避的に微細に鋼中に分散すると、正常粒成長ならびに異常粒成長を抑制するため、添加しないことが好ましい。よって、0.0005％以下とする。より好ましくは、0.0002％以下である。
Ca: 0.0005% or less
Ca is added for deoxidation and precipitation of the solid solution S. If these precipitates are precipitated sufficiently coarsely, the effect of reducing the grain growth suppression effect by reducing the solid solution S is recognized. Inevitably, when finely dispersed in steel, normal grain growth and abnormal grain growth are suppressed. Therefore, it is 0.0005% or less. More preferably, it is 0.0002% or less.
以上、本発明の基本成分について説明した。上記成分以外の残部はＦｅおよび不可避的不純物であるが、その他にも必要に応じて、以下の元素を適宜含有させることができる。 The basic components of the present invention have been described above. The balance other than the above components is Fe and inevitable impurities, but in addition, the following elements can be appropriately contained as required.
SbおよびSnのいずれか１種または２種を合計で0.030％以下
SbおよびSnは、表面に偏析して、焼鈍中鋼板内部への窒素侵入を抑制し、磁気特性劣化の原因となる窒化物の形成を抑制することから、必要に応じて添加してもよい。
ただし、過度に添加された場合には、コストを増大するため、SbおよびSnの少なくともいずれかを合計で0.030％以下とする。より好ましくは、0.010％以下である。
0.030% or less of one or two of Sb and Sn in total
Sb and Sn segregate on the surface, suppress nitrogen penetration into the steel plate during annealing, and suppress the formation of nitrides that cause deterioration of magnetic properties, so may be added as necessary.
However, when added excessively, in order to increase the cost, at least one of Sb and Sn is made 0.030% or less in total. More preferably, it is 0.010% or less.
なお、不可避的不純物において、AlおよびＮは以下の範囲で含まれることとしてもよい。 In the inevitable impurities, Al and N may be included in the following ranges.
Al:0.0050％以下
Alは、AlＮを形成し、粒成長性を著しく損なうため、0.0050％以下とする。より好ましくは、0.0040％以下である。
Al: 0.0050% or less
Al forms AlN and remarkably impairs the grain growth, so 0.0050% or less. More preferably, it is 0.0040% or less.
Ｎ:0.0030％以下
Ｎは、Al、Siと窒化物を形成し、磁気特性を劣化させるため、0.0030％以下とする。より好ましくは、0.0020％以下である。
N: 0.0030% or less N forms 0.0030% or less in order to form nitrides with Al, Si and deteriorate magnetic properties. More preferably, it is 0.0020% or less.
上記以外の元素であっても、工業的に除去できない不可避的不純物であれば含有されていても問題はなく、合計で0.05％未満程度であれば含有されていてもよい。しかし、Ti、Nb、Ｖ、Zrは、磁気特性劣化の原因となる炭窒化物、硫化物等を形成するため、0.001％未満の含有量であることが好ましく、また、不可避的不純物として混在しやすいCuは、硫化物を形成するため、0.005％以下とすることが好ましい。 Even if it is an element other than the above, there is no problem even if it is an inevitable impurity that cannot be removed industrially, and it may be contained if it is less than about 0.05% in total. However, since Ti, Nb, V, and Zr form carbonitrides and sulfides that cause deterioration of magnetic properties, their content is preferably less than 0.001%, and they are mixed as inevitable impurities. Cu, which is easy to form sulfides, is preferably 0.005% or less.
本発明は低圧雰囲気で焼鈍を行うものであることから、特にその低圧雰囲気での焼鈍の前後で鋼中の元素量が変化しやすいが、上記の数値範囲は、焼鈍前の成分組成においても満たされていることが重要である。 Since the present invention performs annealing in a low-pressure atmosphere, the amount of elements in the steel is likely to change before and after annealing in the low-pressure atmosphere, but the above numerical range is satisfied even in the component composition before annealing. It is important that
次に、本発明の一実施形態に係る無方向性電磁鋼板の結晶方位について述べる。
本発明の無方向性電磁鋼板は、(100)の面方位を有する結晶粒が優先的に存在していることとする。
結晶方位は、リガク社製のＸ線単結晶方位測定装置を使用し、ラウエ回折スポットの解析により測定した。
Next, the crystal orientation of the non-oriented electrical steel sheet according to one embodiment of the present invention will be described.
In the non-oriented electrical steel sheet of the present invention, crystal grains having a (100) plane orientation preferentially exist.
The crystal orientation was measured by analyzing a Laue diffraction spot using an X-ray single crystal orientation measuring device manufactured by Rigaku Corporation.
ここで、(100)の面方位を有するとは、結晶中の(100)の結晶面の、圧延面に対する角度の最小値（β角）が3°以内にあることと定義する。また、(100)の面方位を有する結晶粒の存在率は高い方が良く、表面観察によって求めた、(100) の面方位を有する結晶粒の面積率は70％以上とする。より好ましくは、80％以上である。 Here, having a (100) plane orientation is defined as the minimum value (β angle) of the angle of the (100) crystal plane in the crystal with respect to the rolling plane being within 3 °. In addition, the presence rate of the crystal grains having the (100) plane orientation is preferably high, and the area ratio of the crystal grains having the (100) plane orientation determined by surface observation is 70% or more. More preferably, it is 80% or more.
また、本発明例で得られた無方向性電磁鋼板は、(100)の面方位を有する結晶粒の<100>軸がランダムな方向で分散されていることもひとつの特徴である。具体的には、(100)の面方位を有する結晶粒のうち、<100>軸と圧延方向とのなす角（α角）の大きさが35〜45°である結晶粒の割合が12％以上であって、0〜10°である結晶粒の割合も12％以上であった。このため、圧延方向とその直交方向のみならず、圧延方向から圧延面内に45°傾いた方向であっても、極めて良好な磁気特性が得られる。これによって、ΔＢ50を0.10Ｔ以下の異方性の低い磁気特性を得ることができる。 Another feature of the non-oriented electrical steel sheet obtained in the example of the present invention is that the <100> axes of crystal grains having a (100) plane orientation are dispersed in random directions. Specifically, among crystal grains having a (100) plane orientation, the ratio of crystal grains having an angle (α angle) between the <100> axis and the rolling direction of 35 to 45 ° is 12%. The ratio of crystal grains that are 0 to 10 ° was also 12% or more. For this reason, extremely good magnetic properties can be obtained not only in the rolling direction and the direction orthogonal thereto but also in a direction inclined by 45 ° from the rolling direction into the rolling surface. As a result, it is possible to obtain magnetic characteristics with low anisotropy of ΔB 50 of 0.10 T or less.
次に、本発明の一実施形態に係る無方向性電磁鋼板の結晶粒径について述べる。
結晶粒径は、研磨・エッチングした試料表面から光学顕微鏡で測定し、１結晶粒iのＬ方向粒径をdi、面積率をSiとしたとき、平均結晶粒径はΣdi×Siにて定義した。特に1mm以上の結晶粒においては、光学顕微鏡では、粒界の観察が困難であったので、結晶方位測定によって、隣接する結晶粒の方位差（α角、β角）が0.5°以内であれば、結晶粒界は無いものとし、その境界に隣接する２つの結晶は同一の結晶粒に含まれると判断した。
Next, the crystal grain size of the non-oriented electrical steel sheet according to one embodiment of the present invention will be described.
The crystal grain size was measured with an optical microscope from the polished and etched sample surface. When the grain size in the L direction of one crystal grain i was di and the area ratio was Si, the average crystal grain size was defined as Σdi × Si. . Especially for crystal grains of 1 mm or more, it was difficult to observe grain boundaries with an optical microscope, so if the orientation difference (α angle, β angle) of adjacent crystal grains was within 0.5 ° by crystal orientation measurement, It was determined that there was no crystal grain boundary, and two crystals adjacent to the boundary were included in the same crystal grain.
次に、本発明の一実施形態に係る無方向性電磁鋼板の製造方法について説明する。
上記成分組成の数値範囲となるように調整したスラブについて、1200℃以下で再加熱を行う。熱延最終圧延スタンドの出側における板温は800℃以上が好ましい。フェライト組織が粗大化し、冷延焼鈍後の(111)面方位の生成を抑制することができるためである。より好ましくは850℃以上である。スラブの再加熱温度が1200℃より高くなると、粒成長抑制の原因となるMnＳやAlＮの微細分散が生じる。より好ましくは、再加熱温度は1150℃以下である。
Next, the manufacturing method of the non-oriented electrical steel sheet which concerns on one Embodiment of this invention is demonstrated.
About the slab adjusted so that it may become the numerical range of the said component composition, it reheats at 1200 degrees C or less. The plate temperature on the exit side of the hot rolling final rolling stand is preferably 800 ° C. or higher. This is because the ferrite structure becomes coarse and generation of (111) plane orientation after cold rolling annealing can be suppressed. More preferably, it is 850 ° C. or higher. When the reheating temperature of the slab is higher than 1200 ° C., fine dispersion of MnS and AlN causing grain growth suppression occurs. More preferably, the reheating temperature is 1150 ° C. or lower.
スラブの再加熱後は、熱間圧延を行う。熱間圧延後の巻き取り温度は、600℃以下とする。冷間圧延前にＣおよびＮを可能な限り析出させずに固溶させることによって磁気特性に有利な集合組織を形成するためである。 After reheating the slab, hot rolling is performed. The coiling temperature after hot rolling is 600 ° C. or less. This is because C and N are solid-dissolved without precipitation as much as possible before cold rolling to form a texture that is advantageous for magnetic properties.
熱間圧延の仕上げ板厚は薄い方が好ましく、3mm以下とする。なぜなら、熱間仕上厚が厚い場合、続く冷延圧下率が高くなって、磁気特性に好ましくない(111)の結晶面方位が増大するためである。熱間圧延後は、熱延板焼鈍を行っても良いし、行わなくても良い。熱延板焼鈍を行った場合の方が磁気特性上は若干良好な値を示すが、コストが増大するデメリットもある。 The thickness of the hot-rolled finished plate is preferably thin, and should be 3 mm or less. This is because when the hot finish thickness is large, the subsequent cold rolling reduction rate increases, and the (111) crystal plane orientation which is undesirable for the magnetic properties increases. After hot rolling, hot-rolled sheet annealing may or may not be performed. The hot-rolled sheet annealing shows a slightly better value in terms of magnetic properties, but has the disadvantage of increasing costs.
続く冷間圧延で、冷延圧下率が95％以上と過度に高い条件が含まれる場合には、冷延負荷減少のため、熱延板焼鈍を行って軟質化させておくことが好ましい。熱延板焼鈍を行う場合、水素雰囲気あるいはAr雰囲気で行うことがより好ましい。窒素雰囲気にて焼鈍を行うと、地鉄中に窒素が侵入し、磁気特性劣化の原因となる窒化珪素を析出させるためである。 In the subsequent cold rolling, if the cold rolling reduction ratio is excessively high, such as 95% or more, it is preferable to soften by hot-rolled sheet annealing to reduce the cold rolling load. When hot-rolled sheet annealing is performed, it is more preferably performed in a hydrogen atmosphere or an Ar atmosphere. This is because when annealing is performed in a nitrogen atmosphere, nitrogen enters the ground iron and precipitates silicon nitride that causes deterioration of magnetic properties.
続いて、熱延板あるいは熱延焼鈍板を、ショットブラストや塩酸酸洗等の通常の方法でスケール除去をした後、Ｎ回法（Ｎ＝2または3）の冷間圧延を行う。Ｎ回法の冷間圧延とは、Ｎ回の冷間圧延の間に、中間焼鈍工程を挟むことと定義する。上述の通り、Ｎ−１回目の冷間圧延における圧延率は80％以下とし、Ｎ回目の冷間圧延率は80％未満とする。また、Ｎ回目の冷間圧延率は40％以上とする。40％未満であると、結晶粒が過度に粗大化し、低圧雰囲気での焼鈍中に、磁気特性に有利な(100)の面方位を有する結晶粒の成長駆動力が小さくなってしまうためである。より望ましくは50％以上である。 Subsequently, the hot-rolled sheet or hot-rolled annealed sheet is scale-removed by a normal method such as shot blasting or hydrochloric acid pickling, and then cold-rolled by N times (N = 2 or 3). N rolling cold rolling is defined as sandwiching an intermediate annealing step between N cold rollings. As described above, the rolling rate in the (N-1) th cold rolling is 80% or less, and the Nth cold rolling rate is less than 80%. The Nth cold rolling rate is 40% or more. If it is less than 40%, the crystal grains become excessively coarse, and the growth driving force of the crystal grains having the (100) plane orientation advantageous for magnetic properties is reduced during annealing in a low-pressure atmosphere. . More desirably, it is 50% or more.
最終板厚である、冷間圧延後の板厚は0.35mm以下0.05mm以上とする。板厚が過度に厚いと、続く低圧雰囲気での焼鈍において、(100)の面方位を有する結晶粒が十分に形成されない。これは、表面エネルギの駆動力がその他の粒成長駆動力に対して低くなるためと推定している。また、板厚が過度に薄すぎると、冷間圧延の負荷が増大するだけでなく、鋼板のハンドリング性が損なわれ、折れ曲がり変形などを生じやすくなって、磁気特性を劣化させるため好ましくない。中間焼鈍を行う場合には、熱延板焼鈍と同様に、水素雰囲気あるいはAr雰囲気で行うことが好ましい。焼鈍は、組織が軟質化する温度で行えば良いが、800℃以上で行うのが好ましい。これは、組織を粗大化することで、低圧雰囲気での焼鈍の前半で磁気特性向上に好ましい結晶方位の面積率を高めるためである。より好ましくは900℃以上である。 The final thickness is 0.35 mm or less and 0.05 mm or more after cold rolling. When the plate thickness is excessively large, crystal grains having a (100) plane orientation are not sufficiently formed in the subsequent annealing in a low-pressure atmosphere. This is presumed to be because the driving force of surface energy is lower than the driving force of other grain growth. On the other hand, if the plate thickness is too thin, not only the cold rolling load increases, but also the handleability of the steel plate is impaired, bending deformation and the like are likely to occur, and the magnetic properties are deteriorated. When performing the intermediate annealing, it is preferable to perform the annealing in a hydrogen atmosphere or an Ar atmosphere as in the case of the hot rolled sheet annealing. The annealing may be performed at a temperature at which the structure is softened, but is preferably performed at 800 ° C. or higher. This is because the area ratio of crystal orientation preferable for improving magnetic properties is increased in the first half of annealing in a low-pressure atmosphere by coarsening the structure. More preferably, it is 900 ° C. or higher.
また、熱延工程終了後から低圧雰囲気での焼鈍工程の前までに、必要に応じて、上記のスケール除去とは別に、酸洗工程を行い、表面に不可避的に形成された酸化物を、表層酸素（O-Kα）カウント値が250/70msec以下となるまでに調整する。このような酸化物は、熱延中、熱延板焼鈍中、中間焼鈍中いずれの焼鈍中においても、不可避的に混在する水や酸素の存在によって、発生し得る。酸化物の形態としては、SiＯ2やFe2SiＯ4などが認められているが、フッ化水素水あるいは塩酸などの酸との混合液によって酸洗し除去することが可能である。 In addition, after the hot rolling process and before the annealing process in a low-pressure atmosphere, if necessary, separately from the above scale removal, the pickling process is performed, and the oxide inevitably formed on the surface, Adjust until the surface oxygen (O-Kα) count value is 250/70 msec or less. Such an oxide may be generated due to the presence of water and oxygen inevitably mixed during any of the annealing during hot rolling, hot-rolled sheet annealing, and intermediate annealing. As the form of the oxide, SiO 2 , Fe 2 SiO 4, etc. are recognized, but it can be removed by pickling with a mixed solution with an acid such as hydrogen fluoride water or hydrochloric acid.
さらに、本発明者らは、表層酸化物の形成量は、鋼のＳ含有量によって大きく異なることを知見し、Ｓ:7ppm以下であれば、この酸洗工程無しに、表層酸化物を上記の値に抑えることが可能であることを見出した。この原因はまだ明らかになっていないが、このような酸化物は既に熱延板の段階で少なくとも一部が生成されていることがわかっている。 Furthermore, the present inventors have found that the formation amount of the surface layer oxide varies greatly depending on the S content of the steel, and if S: 7 ppm or less, the surface layer oxide is added to the above-mentioned without the pickling step. It was found that it was possible to suppress the value. The cause of this has not yet been clarified, but it has been found that such an oxide has already been produced at least partially at the stage of hot rolling.
また、熱延工程終了後から最終冷間圧延工程の前までに、必要に応じて、特に、Ｓ(ppm)×Ｐ(ppm)＜400を満たさない場合には、非酸化性雰囲気、好ましくは10Pa以下の低圧雰囲気で1050℃以上の温度で焼鈍する。これによって、地鉄中のＳを純化し、5ppm程度以下にまで低減することが可能である。また、この焼鈍を、熱延板焼鈍、あるいは中間焼鈍と兼ねても良い。 Further, from the end of the hot rolling process to before the final cold rolling process, if necessary, particularly when S (ppm) × P (ppm) <400 is not satisfied, a non-oxidizing atmosphere, preferably Annealing is performed at a temperature of 1050 ° C. or higher in a low pressure atmosphere of 10 Pa or lower. As a result, it is possible to purify S in the ground iron and reduce it to about 5 ppm or less. Moreover, this annealing may be combined with hot-rolled sheet annealing or intermediate annealing.
最終板厚まで冷間圧延した鋼板は、低圧雰囲気で焼鈍を行う。低圧雰囲気での圧力は1.0Pa以下とする。過度に低くすると、ポンプ設備などが大型化し製造コスト増を招くので、0.005Pa程度を下限とする。最高到達温度までの平均昇温速度は、30℃/hr以上とするのが生産性の観点から好ましい。さらに好ましくは、10℃/min以上である。最高温度は1100℃以上とし、1100℃以上での保持時間は、5sec以上、より好ましくは20min以上である。 The steel sheet cold-rolled to the final sheet thickness is annealed in a low-pressure atmosphere. The pressure in the low-pressure atmosphere is 1.0 Pa or less. If it is too low, the size of the pump equipment will increase, leading to an increase in manufacturing costs. The average rate of temperature increase up to the maximum temperature is preferably 30 ° C./hr or more from the viewpoint of productivity. More preferably, it is 10 ° C./min or more. The maximum temperature is 1100 ° C. or higher, and the holding time at 1100 ° C. or higher is 5 seconds or longer, more preferably 20 minutes or longer.
（実施例１）
実施例を以下に示す。はじめに表２に示す成分を有する鋼を、ラボでの低圧雰囲気溶解試験にて溶解、鋳造、切削加工して作製したスラブを1150℃に再加熱し、板厚1.8mmあるいは1.3mmまで熱間圧延した。板厚を1.3mmまで熱間圧延した条件は、表３のNo.20からNo.24のみである。仕上げ温度は840℃、巻き取り温度は550℃とした。その後の工程を表３に、得られた特性を表４（熱延板焼鈍温度：950℃）および表５（熱延板焼鈍温度：1020℃）に示す。ここで、表面調整条件とは、熱間圧延後、最終焼鈍前までにおいて行う表面酸化物除去の工程の有無を示したものである。本工程が「有り」の場合は、鋼板をフッ化水素酸と過酸化水素酸の混合液に5sec〜2minの間、浸漬させた。また、磁気特性は、280mm×30mmのサイズの試料を切出し、歪取り焼鈍を行い、エプスタイン試験で評価した。ここで、280mmの方向が、圧延方向のものと、圧延直交方向のもの、さらに圧延方向から-45°および45°面内に傾いた方向のものの４セットを測定し、それぞれの平均値を求めた。また、ΔＢ50の評価は、280mm×30mmの板1枚1枚をSSTにより評価してＢ50を求め、Ｌ方向、Ｃ方向、Ｄ方向(−45°傾いたものと45°傾いたものの平均値)のＢ50のうち、最大値から最小値を引いた値として求めた。表４、５中には、ΔＢ50が0.10Ｔ以上のものには×、0.10Ｔ未満には〇と評価した。
Example 1
Examples are shown below. First, slabs prepared by melting, casting, and cutting steels having the components shown in Table 2 in a low-pressure atmosphere dissolution test in a laboratory are reheated to 1150 ° C and hot rolled to a thickness of 1.8mm or 1.3mm. did. The conditions for hot rolling to a thickness of 1.3 mm are only No. 20 to No. 24 in Table 3. The finishing temperature was 840 ° C and the winding temperature was 550 ° C. The subsequent steps are shown in Table 3, and the obtained characteristics are shown in Table 4 (hot-rolled sheet annealing temperature: 950 ° C.) and Table 5 (hot-rolled sheet annealing temperature: 1020 ° C.). Here, the surface adjustment conditions indicate the presence or absence of a surface oxide removal step performed after hot rolling and before final annealing. When this step was “present”, the steel sheet was immersed in a mixed solution of hydrofluoric acid and hydrogen peroxide acid for 5 seconds to 2 minutes. Magnetic properties were evaluated by an Epstein test by cutting a sample of 280 mm × 30 mm size, performing strain relief annealing. Here, the 280 mm direction is measured in four sets, one in the rolling direction, one in the direction perpendicular to the rolling direction, and one inclined in the -45 ° and 45 ° planes from the rolling direction, and the average value is obtained for each. It was. In addition, ΔB 50 is evaluated by SST for each 280 mm × 30 mm plate to obtain B 50 , and the average of L direction, C direction, D direction (−45 ° tilted and 45 ° tilted) of B 50 value) was determined as a value obtained by subtracting the minimum value from the maximum value. In Tables 4 and 5, when ΔB 50 is 0.10T or more, it was evaluated as x, and when it was less than 0.10T, it was evaluated as ◯.
結晶方位は、Ｘ線ラウエ法により測定した。
また、結晶粒径は、500μm×500μmの領域の光学顕微鏡観察の結果および上述の結晶方位測定の結果をもとに導出した。
The crystal orientation was measured by the X-ray Laue method.
The crystal grain size was derived based on the result of optical microscope observation of a 500 μm × 500 μm region and the result of the crystal orientation measurement described above.
（実施例２）
表６に示す成分を有する鋼を、ラボでの低圧雰囲気溶解試験にて溶解、鋳造、切削加工して作製したスラブを1200℃に再加熱し、板厚3.0mmまで熱間圧延した。仕上げ温度は880℃、巻き取り温度は580℃とした。その後の工程を、表７に示す条件で行った。熱延板焼鈍は省略し、最終仕上げ厚は0.1mmとした。表面調整はしていない。得られた特性を表８に示す。
(Example 2)
A slab produced by melting, casting and cutting steel having the components shown in Table 6 in a low-pressure atmosphere dissolution test in a laboratory was reheated to 1200 ° C. and hot-rolled to a plate thickness of 3.0 mm. The finishing temperature was 880 ° C and the winding temperature was 580 ° C. Subsequent steps were performed under the conditions shown in Table 7. Hot-rolled sheet annealing was omitted and the final finished thickness was 0.1 mm. The surface is not adjusted. Table 8 shows the obtained characteristics.
本発明によれば、磁束密度が高く、さらに低周波鉄損が低いのみならず、高周波鉄損も低い無方向性電磁鋼板を製造することが可能であり、産業上有用である。 According to the present invention, it is possible to produce a non-oriented electrical steel sheet having not only a high magnetic flux density and a low low-frequency iron loss but also a low high-frequency iron loss, which is industrially useful.
Claims (5)
Ｃ:0.0050％以下、
Si:1.00％以上5.00％以下、
Ｐ:0.1000％以下、
Mn:2.00％以下
Ｓ:0.0009％以下および
Ca:0.0005％以下
を含有し、残部はFeおよび不可避的不純物からなる成分組成を有し、
鋼板の表層における(100)面の傾きが圧延面に対して3°以内である結晶粒の総面積率が70％以上であって、圧延方向、圧延方向に対して直角の方向、および圧延方向に対して45°の方向における磁束密度Ｂ50の最大値と最小値との差が0.10Ｔ未満であり、かつ該結晶粒の前記鋼板の圧延方向における平均粒径が10mm以下であることを特徴とする無方向性電磁鋼板。 % By mass
C: 0.0050% or less,
Si: 1.00% to 5.00%,
P: 0.1000% or less,
Mn: 2.00% or less S: 0.0009% or less
Ca: 0.0005% or less, the balance has a component composition consisting of Fe and inevitable impurities,
The total area ratio of crystal grains in which the inclination of the (100) plane in the surface layer of the steel sheet is within 3 ° with respect to the rolling surface is 70% or more, the rolling direction, the direction perpendicular to the rolling direction, and the rolling direction The difference between the maximum value and the minimum value of the magnetic flux density B 50 in the direction of 45 ° is less than 0.10 T, and the average grain size of the crystal grains in the rolling direction of the steel sheet is 10 mm or less. Non-oriented electrical steel sheet.
質量％で、
SbおよびSnのいずれか１種または２種を合計で0.030％以下、含有することを特徴とする、請求項１に記載の無方向性電磁鋼板。 The component composition further includes:
% By mass
The non-oriented electrical steel sheet according to claim 1, wherein one or two of Sb and Sn are contained in a total amount of 0.030% or less.
前記冷間圧延は、計Ｎ回（Ｎ＝2，3）行い、各冷間圧延の間には中間焼鈍を行い、
Ｎ−１回目の冷間圧延における圧延率は80％以下であり、かつ最終の冷間圧延率は40％以上80％未満であり、
前記最終焼鈍は、1.0Pa以下かつ1100℃以上の雰囲気で行うことを特徴とする請求項１または２に記載の無方向性電磁鋼板の製造方法。 A steel material having the component composition according to claim 1 or 2 is hot-rolled, cold-rolled, and a method for producing a non-oriented electrical steel sheet for final annealing,
The cold rolling is performed a total of N times (N = 2, 3), and intermediate annealing is performed between each cold rolling,
The rolling reduction in the (N-1) th cold rolling is 80% or less, and the final cold rolling reduction is 40% or more and less than 80%,
The method for producing a non-oriented electrical steel sheet according to claim 1 or 2, wherein the final annealing is performed in an atmosphere of 1.0 Pa or lower and 1100 ° C or higher.
該熱間圧延後の鋼板を冷間圧延して最終板厚とし、
該最終板厚を有する鋼板を、1.0Pa以下の低圧雰囲気で、1100℃以上の温度で焼鈍し、
前記鋼は、ＰとＳとの含有量（ppm）の積が400未満であり、
前記焼鈍に供される鋼板は、その表層の酸素量が、サンプリング時間を70msec、加速電圧を15kV、スポットサイズを20μｍとしたときの波長分散型検出器によるＯ-Kα線カウント値の総数で250カウント値以下であることを特徴とする請求項１または２に記載の無方向性電磁鋼板の製造方法。 Hot-rolling a steel material having the component composition according to claim 1 or 2,
Cold rolling the steel sheet after the hot rolling to the final thickness,
The steel sheet having the final thickness is annealed at a temperature of 1100 ° C. or higher in a low pressure atmosphere of 1.0 Pa or lower,
The steel has a product of P and S content (ppm) of less than 400,
The steel sheet subjected to the annealing is 250 in total O-Kα ray count value by the wavelength dispersion detector when the surface oxygen amount is 70 msec for sampling time , 15 kV for acceleration voltage, and 20 μm for spot size. It is below a count value, The manufacturing method of the non-oriented electrical steel sheet of Claim 1 or 2 characterized by the above-mentioned .
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