JP2020007637A - Production process of grain-oriented electromagnetic steel sheet - Google Patents
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 37
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- 238000004519 manufacturing process Methods 0.000 title claims description 16
- 238000000137 annealing Methods 0.000 claims abstract description 88
- 238000002791 soaking Methods 0.000 claims abstract description 62
- 238000010438 heat treatment Methods 0.000 claims abstract description 36
- 238000001953 recrystallisation Methods 0.000 claims description 49
- 239000012298 atmosphere Substances 0.000 claims description 48
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 44
- 229910001224 Grain-oriented electrical steel Inorganic materials 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 238000005098 hot rolling Methods 0.000 claims description 7
- 229910052710 silicon Inorganic materials 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
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- 239000003795 chemical substances by application Substances 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 72
- 238000000034 method Methods 0.000 abstract description 39
- 229910052742 iron Inorganic materials 0.000 abstract description 34
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- 238000002474 experimental method Methods 0.000 description 6
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- 229910052782 aluminium Inorganic materials 0.000 description 4
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
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- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
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- 229910052726 zirconium Inorganic materials 0.000 description 1
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Abstract
Description
本発明は、変圧器の鉄心材料として好適な方向性電磁鋼板の製造方法に関するものである。 TECHNICAL FIELD The present invention relates to a method for manufacturing a grain-oriented electrical steel sheet suitable as a core material of a transformer.
方向性電磁鋼板は、変圧器や大型発電機の鉄心材料として用いられる軟磁性材料で、鉄の磁化容易軸である結晶方位の＜００１＞軸が鋼板の圧延方向に高度に揃った結晶集合組織を有している。かような集合組織は、二次再結晶により、Goss方位と称される｛１１０｝＜００１＞方位の結晶粒を優先的に巨大成長させることで得られる。 A grain-oriented electrical steel sheet is a soft magnetic material used as an iron core material for transformers and large generators. The crystal texture in which the <001> axis of the crystal orientation, which is the axis of easy magnetization of iron, is highly aligned with the rolling direction of the steel sheet. have. Such a texture can be obtained by preferentially growing crystal grains of the {110} <001> orientation called Goss orientation by secondary recrystallization.
このような方向性電磁鋼板の製造方法としては、インヒビターと呼ばれる析出物を利用して仕上焼鈍中にGoss方位を有する結晶粒を二次再結晶させることが一般的な技術として知られている。 As a method of manufacturing such a grain-oriented electrical steel sheet, it is known as a general technique to use a precipitate called an inhibitor to secondary recrystallize a crystal grain having a Goss orientation during finish annealing.
例えば、インヒビターと呼ばれる析出物を利用する方法として、特許文献１にはAlN、MnSを利用する方法が、また特許文献２にはMnS、MnSeを利用する方法が開示され、それぞれ工業的に実用化されている。これらのインヒビターを用いる方法は、インヒビター成分の完全固溶のために1300℃以上と高温でのスラブ加熱を必要とするものの、安定して二次再結晶粒を発達させるためには極めて有用な方法であった。 For example, as a method using a precipitate called an inhibitor, Patent Document 1 discloses a method using AlN and MnS, and Patent Document 2 discloses a method using MnS and MnSe. Have been. Although the method using these inhibitors requires slab heating at a high temperature of 1300 ° C or higher for complete solid solution of the inhibitor component, it is an extremely useful method for stably developing secondary recrystallized grains. Met.
さらに、これらのインヒビターの働きを強化するために、特許文献３にはPb、Sb、Nb、Teを利用する方法が、また特許文献４にはZr、Ti、Ｂ、Nb、Ta、Ｖ、Cr、Moを利用する方法が開示されている。 Further, in order to enhance the function of these inhibitors, Patent Document 3 discloses a method utilizing Pb, Sb, Nb, and Te, and Patent Document 4 discloses a method utilizing Zr, Ti, B, Nb, Ta, V, and Cr. , A method utilizing Mo is disclosed.
またさらに、特許文献５には、酸可溶性Al（sol.Al）を0.010〜0.060質量％含有させ、スラブ加熱を低温に抑え、脱炭焼鈍工程で適正な窒化雰囲気下で窒化を行うことにより、二次再結晶焼鈍中に(Al,Si)Ｎを析出させてインヒビターとして用いる方法が提案されている。このような途中工程で窒化処理を行い、(Al,Si)ＮあるいはAlＮをインヒビターとして利用する方法は窒化法と称して数多く提案されている。 Furthermore, Patent Document 5 discloses that by adding 0.010 to 0.060% by mass of acid-soluble Al (sol. Al), suppressing slab heating to a low temperature, and performing nitriding in an appropriate nitriding atmosphere in a decarburizing annealing step, A method has been proposed in which (Al, Si) N is precipitated during secondary recrystallization annealing and used as an inhibitor. Many methods of performing nitriding treatment in such an intermediate step and using (Al, Si) N or AlN as an inhibitor have been proposed as a nitriding method.
一方、インヒビター成分を含有しない素材において、Goss方位結晶粒を二次再結晶により発達させる技術が特許文献６等に開示されている。この技術は、インヒビター成分のような不純物を極力排除することで、一次再結晶時の結晶粒界が持つ粒界エネルギーの粒界方位差角依存性を顕在化させ、インヒビターを用いずともGoss方位を有する結晶粒を二次再結晶させる技術であり、その効果をテクスチャーインヒビション効果と呼んでいる。この方法では、インヒビターの鋼中微細分散が必要ではないため、従来必須とされた高温スラブ加熱が必要でないなど、コスト面でもメンテナンス面でも大きなメリットを有する方法である。 On the other hand, Patent Document 6 and the like disclose a technique for developing Goss-oriented crystal grains by secondary recrystallization in a material containing no inhibitor component. This technology removes impurities such as inhibitor components as much as possible to make the grain boundary orientation angle dependence of the grain boundary energy possessed by the grain boundaries at the time of primary recrystallization evident, so that the Goss orientation can be achieved without using an inhibitor. This is a technique for secondary recrystallization of crystal grains having the following effect, and this effect is called a texture inhibition effect. Since this method does not require fine dispersion of the inhibitor in the steel, it is a method having great advantages in terms of cost and maintenance, such as not requiring high-temperature slab heating, which is conventionally required.
ただし、インヒビター成分を含有しない素材を用いる方法では、一次再結晶焼鈍時に正常粒成長を抑制し、一定の粒径にそろえ、さらに二次再結晶時にGoss方位の先鋭性を高める機能を有するインヒビターが存在しないために、インヒビターを利用する方法よりも、最終的な磁気特性が劣る場合が散見された。 However, in the method using a material that does not contain an inhibitor component, an inhibitor having a function of suppressing normal grain growth during primary recrystallization annealing, adjusting the grain size to a constant value, and further enhancing the sharpness of the Goss orientation during secondary recrystallization. Due to their absence, the final magnetic properties were occasionally inferior to those using inhibitors.
この問題の解決策として、特許文献７には、熱延板焼鈍における昇温速度を速くすることで、インヒビター成分を含有しない素材においても高い磁束密度を有することを可能とする技術が開示されている。
しかしながら、この技術を適用していく過程で、鉄損が悪化するという課題が新たに認められた。この原因は、最終製品板の粒径が粗大となるためと考えられた。
As a solution to this problem, Patent Literature 7 discloses a technique that makes it possible to have a high magnetic flux density even in a material containing no inhibitor component by increasing a heating rate in hot-rolled sheet annealing. I have.
However, in the process of applying this technology, a new problem that iron loss worsens was recognized. This was thought to be due to the grain size of the final product plate becoming coarse.
本発明は、熱延板焼鈍の昇温速度を極力速くした場合、磁束密度は向上するものの、鉄損が悪化するという前述の問題を、二次再結晶焼鈍の加熱パターンを規制すると共に、雰囲気を制御することにより解決するものである。 The present invention solves the above-mentioned problem that the magnetic flux density is improved but the iron loss is deteriorated when the heating rate of the hot-rolled sheet annealing is increased as much as possible, while regulating the heating pattern of the secondary recrystallization annealing and the atmosphere. Is solved by controlling.
以下、本発明を成功に至らしめた実験について説明する。
＜実験１＞
質量％で、Ｃ：0.020％、Si：3.08％、Mn：0.26％、および質量ppmで、Ｎ：18ppm、sol.Al：36ppm、Ｓ：11ppmおよびSe：20ppmを含有する鋼スラブを、連続鋳造にて製造し、1220℃で30分均熱するスラブ加熱を施したのち、熱間圧延により2.2mmの厚さに仕上げた。ついで、乾燥窒素雰囲気中にて1025℃で30秒の熱延板焼鈍を施した。この際、昇温過程において、常温から400℃に到達するまでの昇温速度を75℃/sとし、引き続き400℃から900℃に到達するまでの時間を50秒とした。熱延板焼鈍後、酸洗にて表面のスケールを除去したのち、冷間圧延により0.23mmの最終板厚に仕上げた。さらに、最終板厚に仕上げた鋼板に、50％H2-50％N2、露点50℃の湿潤雰囲気中にて850℃で120秒の脱炭を伴う一次再結晶焼鈍を施した。その後、MgOを主体とする焼鈍分離剤を塗布してから、二次再結晶焼鈍を施し、製品板とした。
Hereinafter, an experiment which has succeeded in the present invention will be described.
<Experiment 1>
Continuous casting of a steel slab containing, by mass%, 0.020% C, 3.08% Si, 0.26% Mn, and 18 ppm N, sol. Al: 36ppm, S: 11ppm and Se: 20ppm by mass ppm. After slab heating by soaking at 1220 ° C. for 30 minutes, it was finished to a thickness of 2.2 mm by hot rolling. Then, hot rolled sheet annealing was performed at 1025 ° C. for 30 seconds in a dry nitrogen atmosphere. At this time, in the heating process, the heating rate from normal temperature to 400 ° C was 75 ° C / s, and the time from 400 ° C to 900 ° C was 50 seconds. After annealing of the hot-rolled sheet, the scale on the surface was removed by pickling, followed by cold rolling to finish to a final sheet thickness of 0.23 mm. Further, the steel sheet finished to the final thickness was subjected to primary recrystallization annealing accompanied by decarburization at 850 ° C. for 120 seconds in a humid atmosphere of 50% H 2 -50% N 2 and a dew point of 50 ° C. Thereafter, an annealing separator mainly composed of MgO was applied, and then subjected to secondary recrystallization annealing to obtain a product plate.
二次再結晶のパターンは、条件Ａ：1200℃で５時間、H2雰囲気下で保定、条件Ｂ：850℃で40時間、N2雰囲気中で保定したのち、1200℃で５時間、H2雰囲気下で保定、条件Ｃ：850℃で40時間保定し、保定時間が20時間まではN2雰囲気とし、20時間から40時間まではAr雰囲気中（非N2雰囲気下）で保定したのち、1200℃で５時間、H2雰囲気下で保定する、の３条件とした。 Secondary recrystallization patterns, Condition A: 1200 ° C. for 5 hours, retention under an atmosphere of H 2 Condition B: at 850 ° C. 40 hours, after retaining in a N 2 atmosphere for 5 hours at 1200 ° C., H 2 Hold in atmosphere, condition C: Hold at 850 ° C for 40 hours, hold in N 2 atmosphere for 20 hours, and hold in Ar atmosphere (non-N 2 atmosphere) for 20 to 40 hours, The conditions were set to be maintained at 1200 ° C. for 5 hours in an H 2 atmosphere.
かくして得られた方向性電磁鋼板からサンプルを切り出し、磁束密度Ｂ8（800A/mで励磁した時の磁束密度）と鉄損Ｗ17/50（交流50Hzで1.7Ｔまで励磁したときの鉄損）をJISC 2550に記載の方法で測定した。
得られた磁束密度Ｂ8と鉄損Ｗ17/50を図１（ａ）、（ｂ）に示す。
同図に示したとおり、磁束密度Ｂ8はどの条件もほぼ同等であったが、鉄損Ｗ17/50は条件Ｃが最も低く良好であることが判明した。
A sample was cut out from the grain- oriented electrical steel sheet thus obtained, and the magnetic flux density B 8 (magnetic flux density when excited at 800 A / m) and iron loss W 17/50 (iron loss when excited to 1.7 T at 50 Hz AC) Was measured by the method described in JISC 2550.
The obtained magnetic flux density B 8 and iron loss W 17/50 are shown in FIGS. 1 (a) and 1 (b).
As shown in the figure, the magnetic flux density B 8 was almost the same under all conditions, but it was found that the condition C was the lowest and the iron loss W 17/50 was favorable.
＜実験２＞
質量％で、Ｃ：0.070％、Si：3.45％、Mn：0.15％、および質量ppmで、Ｎ：20ppm、sol.Al：34ppmおよびＳ：25ppmを含有する鋼スラブを、連続鋳造にて製造し、1260℃で45分均熱するスラブ加熱を施したのち、熱間圧延により2.0mmの厚さに仕上げた。ついで、N2雰囲気中にて1050℃で90秒の熱延板焼鈍を施した。この際、昇温過程において、常温から400℃に到達するまでの昇温速度を100℃/sとし、引き続き400℃から900℃に到達するまでの時間を70秒とした。熱延板焼鈍後、酸洗にて表面のスケールを除去したのち、冷間圧延により0.20mmの最終板厚に仕上げた。さらに、最終板厚に仕上げた鋼板に、60％H2-40％N2、露点55℃の湿潤雰囲気中にて840℃で90秒の脱炭を伴う一次再結晶焼鈍を施した。その後、MgOを主体とする焼鈍分離剤を塗布してから、二次再結晶焼鈍を施し、製品板とした。
<Experiment 2>
A steel slab containing, by mass%, C: 0.070%, Si: 3.45%, Mn: 0.15%, and mass ppm: N: 20ppm, sol. Al: 34ppm and S: 25ppm was produced by continuous casting. After slab heating at 1,260 ° C. for 45 minutes, the slab was hot-rolled to a thickness of 2.0 mm. Subsequently, hot-rolled sheet annealing was performed at 1050 ° C. for 90 seconds in an N 2 atmosphere. At this time, in the heating process, the heating rate from normal temperature to 400 ° C. was 100 ° C./s, and the time from 400 ° C. to 900 ° C. was 70 seconds. After annealing of the hot-rolled sheet, the scale on the surface was removed by pickling and then finished by cold rolling to a final sheet thickness of 0.20 mm. Further, the steel sheet finished to the final thickness was subjected to primary recrystallization annealing with decarburization at 840 ° C. for 90 seconds in a humid atmosphere of 60% H 2 -40% N 2 and a dew point of 55 ° C. Thereafter, an annealing separator mainly composed of MgO was applied, and then subjected to secondary recrystallization annealing to obtain a product plate.
二次再結晶焼鈍は、一次均熱として900℃で50時間保定したのち、二次均熱として1200℃で10時間、水素雰囲気下で保定するパターンとした。この時、一次均熱の雰囲気は、初めにN2雰囲気とし、種々のタイミングでAr雰囲気（非N2雰囲気）に切り替えた。
得られたサンプルの磁束密度Ｂ8と鉄損Ｗ17/50をJIS C 2550に記載の方法で測定した。
得られた磁束密度Ｂ8および鉄損Ｗ17/50をN2の切り替えタイミングで整理した結果を、図２（ａ）、（ｂ）に示す。なお、N2からAr雰囲気への切り替えタイミングは、一次均熱期間（すなわち本実験では50時間）におけるN2雰囲気焼鈍期間の割合で評価した。
その結果、図２に示したとおり、N2雰囲気割合が、10％以下の場合は磁束密度Ｂ8および鉄損Ｗ17/50とも大きく劣化する一方、90％を超えると磁束密度Ｂ8は同等であったが、鉄損Ｗ17/50が悪化する結果となった。
The secondary recrystallization annealing had a pattern in which the temperature was maintained at 900 ° C. as a primary soaking for 50 hours, and then the temperature was maintained as a secondary soaking at 1200 ° C. for 10 hours in a hydrogen atmosphere. At this time, the atmosphere of the primary soaking was initially an N 2 atmosphere, and was switched to an Ar atmosphere (non-N 2 atmosphere) at various timings.
The magnetic flux density B 8 and iron loss W 17/50 of the obtained sample were measured by the method described in JIS C 2550.
FIGS. 2A and 2B show the results of the obtained magnetic flux density B 8 and iron loss W 17/50 arranged at the switching timing of N 2 . The timing of switching from N 2 to the Ar atmosphere was evaluated based on the ratio of the N 2 atmosphere annealing period in the primary soaking period (ie, 50 hours in this experiment).
As a result, as shown in FIG. 2, while N 2 atmosphere ratio is, in the case of 10% or less significantly deteriorated with the magnetic flux density B 8 and iron loss W 17/50 and the magnetic flux density B 8 exceeds 90% equivalent However, the iron loss W 17/50 worsened.
熱延板焼鈍において常温から400℃までを急速に加熱することで磁束密度が向上する理由は、特許文献７に記されている。このような状況下で、二次再結晶焼鈍の一次均熱期間におけるN2雰囲気導入割合を規定することで鉄損が低減する理由は、必ずしも明らかではないが、発明者らは次のように考えている。 The reason why the magnetic flux density is improved by rapidly heating from room temperature to 400 ° C. in hot-rolled sheet annealing is described in Patent Document 7. Under such circumstances, why the iron loss is reduced by defining the N 2 blanketing ratio in the primary soaking period of the secondary recrystallization annealing is not necessarily clear, the inventors, as follows thinking.
鉄損低減の原因を探るべく、実験１で得られたサンプルを85℃の５％HCl水溶液に浸漬して被膜を除去し、二次粒の外観が確認できる状態として、二次粒径を算出したところ、条件Ｃの粒径が最も小さい結果となった。一般的にも、二次粒径が小さいほど、鉄損が低い傾向があるので、鉄損低減効果は、二次粒細粒化の効果であったといえる。 In order to investigate the cause of iron loss reduction, the sample obtained in Experiment 1 was immersed in a 5% HCl aqueous solution at 85 ° C. to remove the coating, and the secondary particle size was calculated so that the appearance of the secondary particles could be confirmed. As a result, the particle size under the condition C was the smallest. Generally, the smaller the secondary particle size is, the lower the iron loss tends to be. Therefore, it can be said that the iron loss reduction effect was an effect of secondary grain refinement.
もともと熱延板焼鈍の急熱の効果は、鋼中のAlN析出物の分布が密にかつ析出物径が小さくなり、二次再結晶後のGoss方位の先鋭性が高まるために発現すると記されている。特に、今回のような中間焼鈍を含まない冷延１回法では、このAlNの分布は二次再結晶焼鈍開始時まで保持されていると考えられる。 Originally, the rapid heating effect of hot-rolled sheet annealing was described as manifested because the distribution of AlN precipitates in the steel was dense and the precipitate diameter was small, and the sharpness of the Goss orientation after secondary recrystallization was increased. ing. In particular, in the single cold rolling method including no intermediate annealing as in this case, it is considered that this AlN distribution is maintained until the start of the secondary recrystallization annealing.
まず、実験１の条件Ａの、一次保定がなく1200℃でH2雰囲気下に保定される場合、昇温中に析出物の分解がH2雰囲気により促進され、その最中に二次再結晶が開始されると考えられる。しかし、この二次再結晶開始後も、焼鈍温度は上昇し続けるため、熱エネルギーが二次再結晶粒粒成長の駆動力となって、結晶粒が極めて大きくなった結果、磁束密度は高いが鉄損が劣化したものと推定される。 First, in the condition A of the experiment 1, when the primary retention is not performed and the temperature is kept at 1200 ° C. in the H 2 atmosphere, the decomposition of the precipitate is promoted by the H 2 atmosphere during the temperature rise, and the secondary recrystallization is performed during the heating. Is thought to be started. However, even after the start of the secondary recrystallization, the annealing temperature continues to rise, so that the thermal energy becomes a driving force for the growth of the secondary recrystallized grains, and the crystal grains become extremely large. It is estimated that iron loss has deteriorated.
次に、条件Ｂの、一次均熱がありその区間はすべてN2雰囲気で焼鈍した場合であるが、800〜950℃で長時間焼鈍されると、雰囲気からＮが鋼中に侵入し、固溶Alやその他窒化物形成元素が窒化物を形成し析出すると考えられる。この析出物の影響で、二次再結晶が開始するまでの一次再結晶粒は焼鈍されているにもかかわらず粒成長をほとんどしないといえる。すなわち、二次再結晶が開始した時点では、一次粒は粒径が小さく、二次再結晶粒の粒成長の駆動力が高い状態にあり、ある場所で二次再結晶が開始するとその二次粒の粒成長は速く進行し、粒径が大きく成長してしまうことが推測される。 Next, the condition B, and all primary soaking is there that interval is a case where the annealing in N 2 atmosphere, when it is a long time annealing at 800 to 950 ° C., N from the atmosphere penetrates into the steel, the solid It is considered that dissolved Al and other nitride-forming elements form and precipitate nitrides. Due to the influence of the precipitate, it can be said that the primary recrystallized grains until the secondary recrystallization starts are hardly grown even though they are annealed. That is, at the time when the secondary recrystallization starts, the primary grains have a small particle size, and the driving force for the grain growth of the secondary recrystallized grains is in a high state. It is presumed that the grain growth proceeds rapidly and the grain size grows large.
これに対し、条件Ｃでは、一次均熱で非N2雰囲気を導入するため、その際は、逆に脱窒が起こり、AlN等の分解が生じると考えられる。分解が起こると、一次粒が若干粒成長するため、二次再結晶粒の粒成長の駆動力を低下させ、二次再結晶が開始しても、その成長が抑制され、結果的に二次粒径が小さくなると推定される。すなわち、二次粒径を小さくし、鉄損を低減するためには、実験２で得られた結果のように、少なくともN2雰囲気導入期間は一次均熱期間の90％以下とし、非N2雰囲気の期間を10％以上導入する必要があるといえる。また、N2雰囲気導入期間が10％以下で磁気特性が大きく劣化したのは、上述のとおり非N2雰囲気により脱窒が進むことで一次粒の粒成長が過剰に促進され、二次再結晶の駆動力が大幅に低下して二次再結晶が不安定になってしまったためと推測される。 On the other hand, under the condition C, since the non-N 2 atmosphere is introduced by the primary soaking, it is considered that denitrification occurs on the contrary and decomposition of AlN or the like occurs. When the decomposition occurs, the primary grains grow slightly, so that the driving force for the growth of the secondary recrystallized grains is reduced, and even when secondary recrystallization starts, the growth is suppressed. It is estimated that the particle size becomes smaller. That is, in order to reduce the secondary particle size and reduce the iron loss, at least the N 2 atmosphere introduction period is set to 90% or less of the primary soaking period and the non-N 2 It can be said that it is necessary to introduce an atmosphere period of 10% or more. The reason why the magnetic properties deteriorated significantly when the N 2 atmosphere introduction period was 10% or less is that, as described above, the denitrification in the non-N 2 atmosphere promoted the primary grain growth excessively, and the secondary recrystallization. It is presumed that the driving force of the semiconductor wafer greatly decreased and secondary recrystallization became unstable.
上述したとおり、本発明者らは、インヒビターレス素材において、熱延板焼鈍の昇温過程における昇温速度や900℃までの到達時間を短時間化すると共に、二次再結晶焼鈍の一次均熱において非N2雰囲気を活用することで、磁気特性を向上させることに成功した。
本発明は上記の知見を基にさらに鋭意研究を重ねて完成したものである。
As described above, the present inventors have found that in inhibitorless materials, while shortening the heating rate and the time required to reach 900 ° C. in the heating process of hot-rolled sheet annealing, the primary soaking of secondary recrystallization annealing By using a non-N 2 atmosphere, the magnetic properties were successfully improved.
The present invention has been completed based on the above findings and further intensive studies.
すなわち、本発明の要旨構成は次のとおりである。
１．質量％で、Ｃ：0.002〜0.100％、Si：1.5〜4.5％およびMn：0.02〜1.00％を含有し、質量ppmで、Ｓ，ＮおよびSeをそれぞれ50ppm以下、sol.Alを100 ppm未満に抑制し、残部はFeおよび不可避的不純物の組成からなる鋼スラブを、1300℃以下の温度に再加熱後、熱間圧延により熱延板としたのち、熱延板焼鈍を施し、ついで１回の冷間圧延により最終板厚の冷延板とし、ついで該冷延板を一次再結晶焼鈍後、鋼板表面に焼鈍分離剤を塗布してから、二次再結晶焼鈍を行う方向性電磁鋼板の製造方法において、
上記熱延板焼鈍における均熱温度を950℃以上とし、その昇温過程において室温から400℃までの温度域を50℃/s以上の速度で昇温し、
上記二次再結晶焼鈍を、800〜950℃で５時間以上保定する一次均熱工程と、1100℃以上で２時間以上保定する二次均熱工程を有するパターンとし、さらに該一次均熱工程において、N2雰囲気で焼鈍する期間を一次均熱期間の20％以上90％以下とし、それ以外は非N2雰囲気で焼鈍することを特徴とする方向性電磁鋼板の製造方法。
That is, the gist configuration of the present invention is as follows.
1. In terms of mass%, C: 0.002 to 0.100%, Si: 1.5 to 4.5% and Mn: 0.02 to 1.00%, S, N and Se are less than 50 ppm and sol.Al is less than 100 ppm in mass ppm. After the steel slab consisting of the composition of Fe and unavoidable impurities is reheated to a temperature of 1300 ° C. or less, a hot-rolled sheet is formed by hot rolling, and then a hot-rolled sheet is annealed. Production of a grain-oriented electrical steel sheet in which a cold-rolled sheet having a final thickness is formed by cold rolling, then the cold-rolled sheet is subjected to primary recrystallization annealing, an annealing separator is applied to the steel sheet surface, and then subjected to secondary recrystallization annealing. In the method,
The soaking temperature in the hot-rolled sheet annealing is 950 ° C. or higher, and the temperature range from room temperature to 400 ° C. is raised at a rate of 50 ° C./s or higher in the heating process,
The secondary recrystallization annealing, a primary soaking step of maintaining at 800 to 950 ° C. for 5 hours or more, and a pattern having a secondary soaking step of maintaining at 1100 ° C. or more for 2 hours or more, further in the primary soaking step , a period for annealing in N 2 atmosphere to 90% or less than 20% of the primary soaking period, the production method of the grain-oriented electrical steel sheet which otherwise characterized by annealing in a non-N 2 atmosphere.
２．前記一次均熱工程における非N2雰囲気をAr雰囲気とすることを特徴とする、前記１記載の方向性電磁鋼板の製造方法。 2. 2. The method for producing a grain-oriented electrical steel sheet according to the above 1, wherein the non-N 2 atmosphere in the primary soaking step is an Ar atmosphere.
３．前記一次均熱工程における非N2雰囲気をAr雰囲気とArを含むかまたはAr以外の非N2雰囲気とし、該Ar雰囲気で焼鈍する期間を前記一次均熱期間の10％以上60％以下とすることを特徴とする前記１記載の方向性電磁鋼板の製造方法。 3. The non-N 2 atmosphere in the primary soaking step includes an Ar atmosphere and a non-N 2 atmosphere other than Ar or a non-N 2 atmosphere other than Ar, and a period of annealing in the Ar atmosphere is 10% or more and 60% or less of the primary soaking period. 2. The method for producing a grain-oriented electrical steel sheet according to the above item 1, wherein
４．前記鋼スラブが、質量％でさらに、Sb：0.01〜0.50％、Sn：0.01〜0.50％、Ni：0.005〜1.5％、Cu：0.005〜1.5％、Cr：0.005〜0.1％、Ｐ：0.005〜0.5％、Mo：0.005〜0.5％およびNb：0.0005〜0.1％のうちから選んだ１種または２種以上を含有することを特徴とする前記１〜３のいずれかに記載の方向性電磁鋼板の製造方法。 4. The steel slab further contains, by mass%, Sb: 0.01 to 0.50%, Sn: 0.01 to 0.50%, Ni: 0.005 to 1.5%, Cu: 0.005 to 1.5%, Cr: 0.005 to 0.1%, P: 0.005 to 0.5 %, Mo: 0.005 to 0.5%, and Nb: 0.0005 to 0.1%, comprising one or more selected from the group consisting of the above-mentioned items 1 to 3, Method.
本発明によれば、インヒビターレス素材において、熱延板焼鈍の昇温過程における昇温速度や900℃までの到達時間を短時間化すると共に、二次再結晶焼鈍の一次均熱において非N2雰囲気を活用して二次再結晶粒を細粒化し、もって磁束密度の向上と同時に鉄損の低減を図ることができる。 According to the present invention, in the inhibitor-less raw material, the heating rate in the heating process of hot-rolled sheet annealing and the time required to reach 900 ° C. are shortened, and the non-N 2 By utilizing the atmosphere, the secondary recrystallized grains can be made finer, so that the magnetic flux density can be improved and the iron loss can be reduced at the same time.
以下、本発明を具体的に説明する。
まず、本発明において鋼スラブの成分組成を前記の範囲に限定した理由について述べる。なお、成分に関する「％」表示は質量％、「ppm」表示は質量ppmをそれぞれ表すものとする。
Ｃ：0.002〜0.100％
Ｃ量が0.100％を超えると、脱炭焼鈍で磁気時効の起こらない0.005％以下に低減することが困難となる。一方、Ｃ量が0.002％未満では熱間脆化が顕著となり、スラブ鋳込みや熱間圧延でのトラブルが多発する。よって、Ｃ量は0.002〜0.100％の範囲とする。好ましくは0.020〜0.070％の範囲である。
Hereinafter, the present invention will be described specifically.
First, the reason why the composition of the steel slab is limited to the above range in the present invention will be described. The “%” and “ppm” of the components indicate mass% and ppm, respectively.
C: 0.002 to 0.100%
If the C content exceeds 0.100%, it becomes difficult to reduce the carbon content to 0.005% or less where magnetic aging does not occur in decarburizing annealing. On the other hand, when the C content is less than 0.002%, hot embrittlement becomes remarkable, and troubles in slab casting and hot rolling frequently occur. Therefore, the C content is in the range of 0.002 to 0.100%. Preferably it is in the range of 0.020 to 0.070%.
Si：1.5〜4.5％
Siは、鋼の比抵抗を高め、鉄損を低減するのに必要な元素である。この効果は、Si量が1.5％未満では十分ではなく、一方4.5％を超えると加工性が低下し、圧延して製造すること困難となる。よって、Si量は1.5〜4.5％の範囲とする。好ましくは2.5〜4.0％の範囲である。
Si: 1.5-4.5%
Si is an element necessary for increasing the specific resistance of steel and reducing iron loss. This effect is not sufficient if the Si content is less than 1.5%, while if it exceeds 4.5%, the workability is reduced and it is difficult to manufacture by rolling. Therefore, the Si content is in the range of 1.5 to 4.5%. Preferably it is in the range of 2.5 to 4.0%.
Mn：0.02〜1.00％
Mnは、鋼の熱間加工性を改善するために必要な元素である。この効果は、Mn量が0.02％未満では十分ではなく、一方1.00％を超えると製品板の磁束密度が低下するようになる。よって、Mn量は0.02〜1.00％の範囲とする。好ましくは0.04〜0.30％の範囲である。
Mn: 0.02-1.00%
Mn is an element necessary for improving the hot workability of steel. This effect is not sufficient when the amount of Mn is less than 0.02%, while when it exceeds 1.00%, the magnetic flux density of the product plate is reduced. Therefore, the Mn content is in the range of 0.02 to 1.00%. Preferably it is in the range of 0.04 to 0.30%.
また本発明では、インヒビター形成元素であるAl、Ｓ、ＮおよびSeは極力除くことが望ましい。しかしながら、工業的には完全に除去することは不可能であることから、Ｓ、ＮおよびSeはそれぞれ50ppm以下、またsol.Alは100 ppm未満であれば残存を許容するものとした。 In the present invention, Al, S, N, and Se, which are inhibitor-forming elements, are desirably removed as much as possible. However, since it is impossible to completely remove it industrially, it is assumed that S, N, and Se are allowed to remain if 50 ppm or less and sol. Al is less than 100 ppm, respectively.
さらに本発明では、磁束密度を向上させる目的で、Sb：0.01〜0.50％、Sn：0.01〜0.50％、Ni：0.005〜1.5％、Cu：0.005〜1.5％、Cr：0.005〜0.1％、Ｐ：0.005〜0.5％、Mo：0.005〜0.5％およびNb：0.0005〜0.1％のうちから選んだ１種または２種以上を、単独または複合して含有させることができる。各元素の含有量が下限値より少ない場合には磁束密度の向上効果に乏しく、一方上限値を超えると二次再結晶不良を招き、磁気特性の劣化をきたす。 Further, in the present invention, in order to improve the magnetic flux density, Sb: 0.01 to 0.50%, Sn: 0.01 to 0.50%, Ni: 0.005 to 1.5%, Cu: 0.005 to 1.5%, Cr: 0.005 to 0.1%, P: One or more selected from 0.005 to 0.5%, Mo: 0.005 to 0.5%, and Nb: 0.0005 to 0.1% can be contained alone or in combination. When the content of each element is less than the lower limit, the effect of improving the magnetic flux density is poor. On the other hand, when the content exceeds the upper limit, secondary recrystallization failure is caused and the magnetic properties are deteriorated.
次に、本発明の製造方法について述べる。製造方法は一般的な電磁鋼板を製造する方法を利用できる。
すなわち、所定の成分調整がなされた溶鋼を、通常の造塊法もしくは連続鋳造法で鋼スラブとする。前述した添加成分については、途中工程で加えることは困難であるので、溶鋼段階で添加することが望ましい。鋼スラブは、通常の方法で加熱して熱間圧延に供される。本発明の成分系では、AlやＮが低減されているため、これらを固溶させるための高温加熱を必要とせず、1300℃以下の低温とすることができ、これによりコスト低減が達成される。なお、加熱温度の下限は1100℃程度が好適である。
Next, the manufacturing method of the present invention will be described. As a manufacturing method, a general method of manufacturing an electromagnetic steel sheet can be used.
That is, the molten steel having been subjected to the predetermined component adjustment is made into a steel slab by a normal ingot making method or a continuous casting method. Since it is difficult to add the above-mentioned additional components in the middle of the process, it is desirable to add them at the molten steel stage. The steel slab is heated in a usual manner and subjected to hot rolling. In the component system of the present invention, since Al and N are reduced, high-temperature heating for dissolving them is not required, and the temperature can be lowered to 1300 ° C. or lower, thereby achieving cost reduction. . Note that the lower limit of the heating temperature is preferably about 1100 ° C.
次いで、熱延板焼鈍を施すが、この熱延板焼鈍においては。前述した理由により、昇温過程において室温から400℃までの温度域における昇温速度を50℃/s以上とすることが必要である。また、400℃から900℃に到達するまでの時間は100秒以下とすることが望ましい。さらに望ましくは、昇温速度は100℃/s以上であり、400℃から900℃までの到達時間は60秒以下である。なお、昇温速度の上限は300℃/s程度とするのが好ましい。
さらに、鋼中のSi3N4析出物からAlN析出物への置換を確実とするために、熱延板焼鈍における均熱温度を950℃以上とすることも不可欠である。均熱温度は望ましくは、1000℃以上1100℃以下である。1000℃未満では析出物の置換が十分でなく、磁性が劣化する可能性がある。一方、1100℃超では二次再結晶が不安定となる可能性がある。
加熱方法については特に制限はないが、50℃/s以上の昇温速度を達成させるためには、従来のヒーターやバーナーによる加熱方法の他、誘導加熱方法や通電加熱方法が考えられる。
Next, hot-rolled sheet annealing is performed, and in this hot-rolled sheet annealing. For the above-mentioned reason, it is necessary to set the heating rate in the temperature range from room temperature to 400 ° C. in the heating process at 50 ° C./s or more. Further, the time required to reach from 400 ° C. to 900 ° C. is desirably 100 seconds or less. More desirably, the rate of temperature rise is 100 ° C./s or more, and the arrival time from 400 ° C. to 900 ° C. is 60 seconds or less. Note that the upper limit of the heating rate is preferably about 300 ° C./s.
Furthermore, in order to ensure the replacement of Si 3 N 4 precipitates in steel with AlN precipitates, it is essential to set the soaking temperature in hot-rolled sheet annealing to 950 ° C. or higher. The soaking temperature is desirably 1000 ° C. or more and 1100 ° C. or less. If the temperature is lower than 1000 ° C., the replacement of the precipitate is not sufficient, and the magnetism may be deteriorated. On the other hand, if it exceeds 1100 ° C., the secondary recrystallization may be unstable.
The heating method is not particularly limited, but in order to achieve a heating rate of 50 ° C./s or more, an induction heating method or an energization heating method can be considered in addition to a conventional heating method using a heater or a burner.
上記の熱延板焼鈍後、冷間圧延により最終板厚の冷延板である鋼板としたのち、一次再結晶焼鈍を行う。この冷間圧延では、鋼板温度を100〜300℃に上昇させて行うことや、冷間圧延の途中で100〜300℃の範囲での時効処理を１回または複数回行うことが、再結晶集合組織を変化させて磁気特性を向上させる上で有効である。また、本発明では、前述した理由により、冷間圧延法は中間焼鈍を挟まない冷延１回法に限定される。 After the above hot-rolled sheet annealing, a cold-rolled steel sheet having a final thickness is formed by cold rolling, and then subjected to primary recrystallization annealing. In this cold rolling, the temperature of the steel sheet is raised to 100 to 300 ° C., and one or more aging treatments in the range of 100 to 300 ° C. are performed during the cold rolling, and the recrystallization aggregation is performed. This is effective in improving the magnetic properties by changing the structure. In the present invention, the cold rolling method is limited to the single cold rolling method without intermediate annealing for the above-mentioned reason.
一次再結晶焼鈍では、鋼板の脱炭を兼ねさせてもよい。焼鈍温度は、800℃以上900℃以下が脱炭性の観点から好適である。また脱炭の観点からは、雰囲気は湿潤雰囲気とすることが望ましい。ただし、脱炭が不要なＣを0.005％以下しか含有していない場合は、上記以外の条件でも問題ない。さらに、一次再結晶焼鈍における保定温度までの昇温速度は50℃/s以上400℃/s以下とすることが最終磁気特性を良好とする上で望ましい。 In the primary recrystallization annealing, the steel sheet may be decarburized. The annealing temperature is preferably from 800 ° C. to 900 ° C. from the viewpoint of decarburization. From the viewpoint of decarburization, the atmosphere is desirably a humid atmosphere. However, if the content of C that does not require decarburization is only 0.005% or less, there is no problem under the conditions other than the above. Further, it is desirable that the rate of temperature rise up to the holding temperature in the primary recrystallization annealing be 50 ° C./s or more and 400 ° C./s or less in order to improve the final magnetic properties.
ついで、鋼板正面にMgOを主体とする焼鈍分離剤を塗布してから、二次再結晶焼鈍を施してGoss方位を有する二次粒を発達させると共に、フォルステライト被膜を形成させる。
ここに、二次再結晶焼鈍は、800〜950℃で５時間以上保定する一次均熱工程と1100℃以上で２時間以上保定する二次均熱工程を有するものとし、さらに一次均熱工程において、N2雰囲気で焼鈍する期間を一次均熱期間の20％以上90％以下とし、それ以外は非N2雰囲気で焼鈍する、すなわち非N2雰囲気で焼鈍する期間は一次均熱期間の10％以上80％以下とすることが重要である。
Then, an annealing separator mainly composed of MgO is applied to the front surface of the steel sheet, and then subjected to secondary recrystallization annealing to develop secondary grains having a Goss orientation and form a forsterite film.
Here, the secondary recrystallization annealing shall have a primary soaking step of maintaining at 800 to 950 ° C for 5 hours or more and a secondary soaking step of maintaining at 1100 ° C or more for 2 hours or more. The annealing period in the N 2 atmosphere is 20% or more and 90% or less of the primary soaking period, and other than that, annealing in a non-N 2 atmosphere is performed. That is, the annealing period in the non-N 2 atmosphere is 10% of the primary soaking period. It is important that it is not less than 80%.
一次均熱温度が800℃未満の場合は二次再結晶が起こらず、一方950℃を超えると磁束密度Ｂ8が劣化する。一次均熱時間が５時間に満たないと二次再結晶が十分でない。また、一次均熱は20時間以上行うことが二次再結晶の発現安定化のために有効である。なお一次均熱時間の上限は100時間が好ましい。また、二次均熱が1100℃未満の場合は、純化不足となり、鉄損が大幅に低下する。そして、二次均熱は1175℃以上で５時間以上保定とすることが安定して純化を達成する観点から極めて有効である。なお、二次均熱時間の上限は20時間とするのが好ましい。また二次均熱における雰囲気はH2雰囲気とすることが好ましい。 When the primary soaking temperature is less than 800 ° C., secondary recrystallization does not occur, while when it exceeds 950 ° C., the magnetic flux density B 8 deteriorates. If the primary soaking time is less than 5 hours, secondary recrystallization is not sufficient. It is effective to perform the primary soaking for 20 hours or more to stabilize the onset of secondary recrystallization. The upper limit of the primary soaking time is preferably 100 hours. On the other hand, if the secondary soaking is lower than 1100 ° C., purification becomes insufficient, and iron loss is significantly reduced. It is extremely effective to keep the secondary soaking at 1175 ° C. or more for 5 hours or more from the viewpoint of stably achieving purification. The upper limit of the secondary soaking time is preferably set to 20 hours. The atmosphere in the secondary soaking is preferably an H 2 atmosphere.
さらに、一次均熱工程におけるN2導入期間は、全期間の50％以上70％未満とすることが好ましい。また、一次均熱工程における非N2雰囲気としては、前述したArの他、H2やHeなどが有利に適合し、これらの混合ガスや、これら非N2雰囲気ガスを切り替えて使用しても問題はない。特に、後述する実施例の通り、非N2雰囲気ガスをAr雰囲気とし、かかるAr雰囲気で焼鈍する期間を一次均熱期間の10％以上60％以下とすると、さらに鉄損が低減するため望ましい。なお、ArやH2、Heを用いる場合、ArやH2、He等を適宜切り替える、または混合する等して、併せて用いることができる。この場合は、非N2雰囲気ガス全体で一次均熱期間の10％以上80％以下とすれば本発明の効果を得られるが、Ar雰囲気で焼鈍する期間は一次均熱期間の10％以上60％以下とするのが鉄損低減の観点から望ましい。また、非N2雰囲気がAr雰囲気のときはかかるAr雰囲気の期間を10〜60％、残りの一次均熱工程の期間をN2雰囲気とすることがより好ましい。 Further, N 2 in period in the primary soaking step is preferably 50% or more and less than 70% of the entire period. In addition, as the non-N 2 atmosphere in the primary soaking step, in addition to the above-described Ar, H 2 , He, or the like is advantageously adapted, and a mixed gas thereof or a non-N 2 atmosphere gas may be used by switching. No problem. In particular, as in the embodiments described later, it is preferable that the non-N 2 atmosphere gas be an Ar atmosphere and the period of annealing in the Ar atmosphere be 10% or more and 60% or less of the primary soaking period, since iron loss is further reduced. When Ar, H 2 , or He is used, Ar, H 2 , He, or the like can be used together by appropriately switching or mixing. In this case, the effect of the present invention can be obtained by setting the entire non-N 2 atmosphere gas to 10% or more and 80% or less of the primary soaking period. However, the annealing period in the Ar atmosphere is 10% to 60% of the primary soaking period. % Is desirable from the viewpoint of reducing iron loss. Further, when the non-N 2 atmosphere is an Ar atmosphere, it is more preferable that the period of the Ar atmosphere be 10 to 60% and the remaining period of the primary soaking step be the N 2 atmosphere.
上記の二次再結晶焼鈍後は、付着した焼鈍分離剤を除去するため、水洗やブラッシング、酸洗を行うことが有用である。その後、さらに平坦化焼鈍を行って形状を矯正することが鉄損低減のために有効である。
鋼板を積層して使用する場合には、鉄損を改善するために、平坦化焼鈍前もしくは後に、鋼板表面に絶縁コーティングを施すことが有効である。この場合、鋼板に張力を付与できるコーティングとすることが鉄損低減の面で望ましい。このとき、バインダーを介した張力コーティング塗布方法や物理蒸着法や化学蒸着法により無機物を鋼板表層に蒸着させコーティングとする方法を採用すると、コーティング密着性に優れ、かつ著しい鉄損低減効果があるため望ましい。
After the above-mentioned secondary recrystallization annealing, it is useful to perform water washing, brushing, and acid washing in order to remove the attached annealing separating agent. After that, it is effective to further reduce the iron loss by performing flattening annealing to correct the shape.
When steel sheets are stacked and used, it is effective to apply an insulating coating to the steel sheet surface before or after flattening annealing in order to improve iron loss. In this case, it is desirable to use a coating that can apply tension to the steel sheet from the viewpoint of reducing iron loss. At this time, if a method in which an inorganic substance is deposited on the surface layer of the steel sheet by a coating method such as a tension coating application method via a binder, a physical vapor deposition method, or a chemical vapor deposition method to form a coating is adopted, the coating is excellent in adhesion and has a significant iron loss reduction effect. desirable.
（実施例１）
Ｃ：0.015％、Si：2.78％、Mn：0.04％、sol.Al：50ppm、Ｎ：27ppm、Ｓ：９ppmおよびSe：40ppmを含み、残部はFeおよび不可避的不純物の組成からなる鋼スラブを、連続鋳造にて製造し、1170℃でスラブ加熱後、熱間圧延により1.6mmの厚さに仕上げた。ついで、90vol％N2＋10vol％CO2、露点40℃の雰囲気中にて975℃で80秒の熱延板焼鈍を施した。その際、昇温過程において、常温から400℃に到達するまでの昇温速度を表１に示すように種々に変更した。ついで、酸洗にて表面のスケールを除去したのち、冷間圧延により0.23mmの最終板厚に仕上げた。その後、50vol％H2-50vol％N2、露点50℃の湿潤雰囲気中にて850℃で60秒の脱炭を伴う一次再結晶焼鈍を施した。さらに、MgOを主体とする焼鈍分離剤を塗布してから、900℃で40時間の一次均熱後に、H2雰囲気中にて1220℃で５時間の二次均熱を施す二次再結晶焼鈍を行った。一次均熱の際、一部はN2雰囲気とし、それ以外はAr雰囲気とし、一次均熱期間においてN2雰囲気で焼鈍する割合を表１に示すとおり種々変化させた。ただし、6-2は、Ar雰囲気の一部をさらに、H2雰囲気とした。すなわち、6-2は、一次均熱期間においてN2雰囲気が20％、Ar雰囲気が60％、H2雰囲気が20％である。また、6-3は、Ar雰囲気の一部をさらに、30vol％ArのH2雰囲気とした。すなわち、6-３は、一次均熱期間においてN2雰囲気が20％、Ar雰囲気が60％、30vol％Ar＋70vol％H2雰囲気が20％である。
得られたサンプルの磁束密度Ｂ8および鉄損Ｗ17/50について調べた結果を表１に併記する。
(Example 1)
A steel slab containing C: 0.015%, Si: 2.78%, Mn: 0.04%, sol. Al: 50 ppm, N: 27 ppm, S: 9 ppm and Se: 40 ppm, with the balance being Fe and inevitable impurities, Manufactured by continuous casting, the slab was heated at 1170 ° C, and finished to a thickness of 1.6 mm by hot rolling. Then, hot rolled sheet annealing was performed at 975 ° C. for 80 seconds in an atmosphere of 90 vol% N 2 +10 vol% CO 2 and a dew point of 40 ° C. At that time, in the heating process, the heating rate from normal temperature to 400 ° C. was variously changed as shown in Table 1. Then, after removing the scale on the surface by pickling, it was finished to a final thickness of 0.23 mm by cold rolling. Thereafter, primary recrystallization annealing with decarburization was performed at 850 ° C. for 60 seconds in a humid atmosphere of 50 vol% H 2 -50 vol% N 2 and a dew point of 50 ° C. Further, after applying an annealing separator mainly composed of MgO, after primary soaking at 900 ° C. for 40 hours, secondary recrystallization annealing in which a secondary soaking is performed at 1220 ° C. for 5 hours in an H 2 atmosphere. Was done. At the time of the primary soaking, part was made into an N 2 atmosphere, and the rest was made into an Ar atmosphere, and the annealing rate in the N 2 atmosphere during the primary soaking period was variously changed as shown in Table 1. However, in 6-2, a part of the Ar atmosphere was further changed to an H 2 atmosphere. That is, in the case of 6-2, the N 2 atmosphere is 20%, the Ar atmosphere is 60%, and the H 2 atmosphere is 20% in the primary soaking period. In 6-3, a part of the Ar atmosphere was further changed to a 30 vol% Ar H 2 atmosphere. That is, in 6-3, the N 2 atmosphere is 20%, the Ar atmosphere is 60%, and the 30 vol% Ar + 70 vol% H 2 atmosphere is 20% in the primary soaking period.
Table 1 also shows the results of an examination on the magnetic flux density B 8 and iron loss W 17/50 of the obtained sample.
同表から明らかなように、本発明に従う条件で製造した方向性電磁鋼板はいずれも、良好な磁束密度Ｂ8と鉄損Ｗ17/50を得ることができた。また、発明例の中でも、特に、同表の条件No.6-1の結果と比較して、No.6-2、6-3、7、8、9、10、13、16の結果の方が良好な鉄損値を示していることから、Ar雰囲気の期間が10〜60％の範囲内の場合、さらに良好な鉄損が得られることがわかる。 As it is apparent from the table, both oriented electrical steel sheet produced under the conditions according to the invention, it was possible to obtain a good magnetic flux density B 8 and iron loss W 17/50. Also, among the invention examples, in particular, the results of Nos. 6-2, 6-3, 7, 8, 9, 10, 13, and 16 were compared with the results of condition No. 6-1 in the same table. Indicates that a good iron loss value is obtained when the Ar atmosphere period is in the range of 10 to 60%.
（実施例２）
表２に示す成分を含み、残部はFeおよび不可避的不純物の組成からなる鋼スラブを、連続鋳造にて製造し、1200℃でスラブ加熱後、熱間圧延により2.4mmの厚さに仕上げた。ついで、N2雰囲気中にて1060℃で45秒の熱延板焼鈍を施した。その際、昇温過程において、常温から400℃に到達するまでの昇温速度を100℃/ｓとした。ついで、熱延板焼鈍後、酸洗にて表面のスケールを除去したのち、150℃の温間圧延にて0.27mmの最終板厚に仕上げた。その後、55vol％H2-45vol％N2、露点50℃の湿潤雰囲気下の850℃で150秒の脱炭を伴う一次再結晶焼鈍を施した。さらに、MgOを主体とする焼鈍分離剤を塗布してから、920℃で30時間の一次均熱後に、H2雰囲気中にて1200℃で10時間の二次均熱を施す二次再結晶焼鈍を行った。一次均熱の際、一部はN2雰囲気としそれ以外はH2雰囲気とした。また、一次均熱期間にN2雰囲気で焼鈍する期間の割合は75％とした。
得られたサンプルの磁束密度Ｂ8および鉄損Ｗ17/50について調べた結果を表２に併記する。
(Example 2)
A steel slab containing the components shown in Table 2 and having the balance of Fe and unavoidable impurities was manufactured by continuous casting, heated at 1200 ° C., and finished to a thickness of 2.4 mm by hot rolling. Subsequently, hot rolled sheet annealing was performed at 1060 ° C. for 45 seconds in an N 2 atmosphere. At that time, in the heating process, the heating rate from normal temperature to 400 ° C. was set to 100 ° C./s. Then, after annealing the hot-rolled sheet, the scale on the surface was removed by pickling, and the sheet was warm-rolled at 150 ° C. to a final sheet thickness of 0.27 mm. Thereafter, primary recrystallization annealing accompanied by decarburization for 150 seconds at 850 ° C. in a humid atmosphere with 55 vol% H 2 -45 vol% N 2 and a dew point of 50 ° C. was performed. Furthermore, after applying an annealing separator mainly composed of MgO, after primary soaking at 920 ° C. for 30 hours, secondary recrystallization annealing in which a secondary soaking is performed at 1200 ° C. for 10 hours in an H 2 atmosphere. Was done. At the time of the primary soaking, a part was set to the N 2 atmosphere, and the others were set to the H 2 atmosphere. The ratio of the period of annealing in the N 2 atmosphere during the primary soaking period was 75%.
Table 2 also shows the results of an examination on the magnetic flux density B 8 and iron loss W 17/50 of the obtained sample.
同表に示したとおり、成分組成が本発明の範囲を満足する場合には、良好な磁束密度Ｂ8と鉄損Ｗ17/50が得られている。
As shown in the table, when the component composition satisfies the range of the present invention, good magnetic flux density B 8 and iron loss W 17/50 were obtained.
Claims (4)
上記熱延板焼鈍における均熱温度を950℃以上とし、その昇温過程において室温から400℃までの温度域を50℃/s以上の速度で昇温し、
上記二次再結晶焼鈍を、800〜950℃で５時間以上保定する一次均熱工程と、1100℃以上で２時間以上保定する二次均熱工程を有するものとし、さらに該一次均熱工程において、N2雰囲気で焼鈍する期間を一次均熱期間の20％以上90％以下とし、それ以外は非N2雰囲気で焼鈍することを特徴とする方向性電磁鋼板の製造方法。 By mass%, C: 0.002 to 0.100%, Si: 1.5 to 4.5% and Mn: 0.02 to 1.00%, S, N and Se are less than 50 ppm and sol.Al is less than 100 ppm by mass ppm. After the steel slab consisting of the composition of Fe and unavoidable impurities is reheated to a temperature of 1300 ° C. or less, a hot-rolled sheet is formed by hot rolling, and then a hot-rolled sheet is annealed. Cold-rolled to a cold-rolled sheet having a final thickness, after the cold-rolled sheet is subjected to primary recrystallization annealing, after applying an annealing separating agent to the steel sheet surface, and then subjected to secondary recrystallization annealing method for producing a grain-oriented electrical steel sheet At
The soaking temperature in the hot-rolled sheet annealing is 950 ° C. or higher, and the temperature range from room temperature to 400 ° C. is raised at a rate of 50 ° C./s or higher in the heating process,
The secondary recrystallization annealing has a primary soaking step of maintaining at 800 to 950 ° C. for 5 hours or more, and a secondary soaking step of maintaining at 1100 ° C. or more for 2 hours or more. , a period for annealing in N 2 atmosphere to 90% or less than 20% of the primary soaking period, the production method of the grain-oriented electrical steel sheet which otherwise characterized by annealing in a non-N 2 atmosphere.
The steel slab further contains, by mass%, Sb: 0.01 to 0.50%, Sn: 0.01 to 0.50%, Ni: 0.005 to 1.5%, Cu: 0.005 to 1.5%, Cr: 0.005 to 0.1%, P: 0.005 to 0.5 %, Mo: 0.005 to 0.5%, and Nb: 0.0005 to 0.1%, and contains one or more selected from the group consisting of: Steel plate manufacturing method.
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