JP6572956B2 - Method for producing grain-oriented electrical steel sheet - Google Patents
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- 229910001224 Grain-oriented electrical steel Inorganic materials 0.000 title claims description 31
- 238000004519 manufacturing process Methods 0.000 title claims description 29
- 238000000137 annealing Methods 0.000 claims description 120
- 229910000831 Steel Inorganic materials 0.000 claims description 62
- 239000010959 steel Substances 0.000 claims description 62
- 238000001953 recrystallisation Methods 0.000 claims description 52
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 48
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 42
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 34
- 238000000034 method Methods 0.000 claims description 31
- 229910052742 iron Inorganic materials 0.000 claims description 19
- 229910052757 nitrogen Inorganic materials 0.000 claims description 18
- 238000005097 cold rolling Methods 0.000 claims description 16
- 229910052717 sulfur Inorganic materials 0.000 claims description 16
- 230000005381 magnetic domain Effects 0.000 claims description 14
- 229910052802 copper Inorganic materials 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 9
- 229910052748 manganese Inorganic materials 0.000 claims description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 229910052718 tin Inorganic materials 0.000 claims description 5
- 238000010894 electron beam technology Methods 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 36
- 239000003112 inhibitor Substances 0.000 description 29
- 238000010438 heat treatment Methods 0.000 description 25
- 239000012298 atmosphere Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 15
- 239000000047 product Substances 0.000 description 15
- 229910052739 hydrogen Inorganic materials 0.000 description 13
- 238000005096 rolling process Methods 0.000 description 13
- 238000005098 hot rolling Methods 0.000 description 10
- 238000005261 decarburization Methods 0.000 description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 8
- 230000004907 flux Effects 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 229910052711 selenium Inorganic materials 0.000 description 8
- 239000002244 precipitate Substances 0.000 description 7
- 239000002344 surface layer Substances 0.000 description 7
- 229910052787 antimony Inorganic materials 0.000 description 6
- 239000012299 nitrogen atmosphere Substances 0.000 description 6
- 229910000976 Electrical steel Inorganic materials 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- ILRRQNADMUWWFW-UHFFFAOYSA-K aluminium phosphate Chemical compound O1[Al]2OP1(=O)O2 ILRRQNADMUWWFW-UHFFFAOYSA-K 0.000 description 5
- 239000008119 colloidal silica Substances 0.000 description 5
- 230000002401 inhibitory effect Effects 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 238000005121 nitriding Methods 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000005498 polishing Methods 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 238000003303 reheating Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 230000001629 suppression Effects 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 239000012300 argon atmosphere Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000011162 core material Substances 0.000 description 2
- 230000008034 disappearance Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 150000004763 sulfides Chemical class 0.000 description 2
- -1 sulfuric acid compound Chemical class 0.000 description 2
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- MAHNFPMIPQKPPI-UHFFFAOYSA-N disulfur Chemical compound S=S MAHNFPMIPQKPPI-UHFFFAOYSA-N 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910052839 forsterite Inorganic materials 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- QHGNHLZPVBIIPX-UHFFFAOYSA-N tin(II) oxide Inorganic materials [Sn]=O QHGNHLZPVBIIPX-UHFFFAOYSA-N 0.000 description 1
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Description
本発明は、主として変圧器や発電機等の鉄心に用いられる方向性電磁鋼板、より具体的には板厚が0.14〜0.24mmの極薄かつ低鉄損の方向性電磁鋼板の製造方法に関するものである。 The present invention relates to a grain-oriented electrical steel sheet mainly used for iron cores such as transformers and generators, and more specifically to a method for manufacturing a grain-oriented electrical steel sheet having a thickness of 0.14 to 0.24 mm and an extremely thin and low iron loss. It is.
Siを含有し、結晶方位が[110]<001>方位（Goss方位）や[100]<001>方位（Cube方位）に高度に配向した方向性電磁鋼板は、優れた軟磁気特性を示すことから、商用周波数領域で用いられる各種電気機器の鉄心材料として広く用いられている。このような用途に用いられる方向性電磁鋼板は、一般に、50Hzの周波数で1.7Ｔに磁化させたときの磁気損失を表す鉄損Ｗ17/50（W/kg）が低いことが求められる。その理由は、発電機や変圧器の効率は、Ｗ17/50の値が低い鉄心材料を用いることで、大幅に向上させることができるからである。そのため、鉄損の低い材料の開発が益々強く求められるようになってきている。 A grain-oriented electrical steel sheet containing Si and highly oriented in the [110] <001> orientation (Goss orientation) and [100] <001> orientation (Cube orientation) should exhibit excellent soft magnetic properties. Therefore, it is widely used as a core material for various electric devices used in the commercial frequency range. The grain-oriented electrical steel sheet used for such applications is generally required to have a low iron loss W 17/50 (W / kg) representing magnetic loss when magnetized to 1.7T at a frequency of 50 Hz. The reason is that the efficiency of generators and transformers can be greatly improved by using iron core materials with low W 17/50 values. Therefore, development of materials with low iron loss has been increasingly demanded.
電磁鋼板の鉄損は、結晶方位や純度等に依存するヒステリシス損と、板厚や比抵抗、磁区の大きさ等に依存する渦電流損との和で表される。したがって、鉄損を低減する方法としては、結晶方位の集積度を高めて磁束密度を向上し、ヒステリシス損を低減する方法や電気抵抗を高めるSiの含有量を増加させたり、鋼板の板厚を低減したり、磁区を細分化したりすることで渦電流損を低減する方法等が知られている。 The iron loss of an electrical steel sheet is represented by the sum of hysteresis loss that depends on crystal orientation and purity, and eddy current loss that depends on sheet thickness, specific resistance, magnetic domain size, and the like. Therefore, methods for reducing iron loss include increasing the degree of integration of crystal orientation to improve magnetic flux density, reducing hysteresis loss, increasing the Si content to increase electrical resistance, and increasing the thickness of the steel sheet. A method of reducing eddy current loss by reducing or subdividing magnetic domains is known.
これらの鉄損低減方法のうち、ヒステリシス損を低減させるべく磁束密度を向上させる方法に関しては、例えば特許文献１および特許文献２に、AlNをインヒビターとする方向性電磁鋼板を製造するに際し、Niを添加しかつNi添加量に応じてSbを所定の範囲で添加することで、一次再結晶粒の正常粒成長に対し極めて強い抑制力効果を発揮させ、一次再結晶粒集合組織の改善と二次再結晶粒の微細化を図ると共に、[110]<001>方位の圧延方向に対する平均面内ずれ角を小さくすることにより、鉄損を大幅に低減する技術が開示されている。 Of these iron loss reduction methods, regarding the method of improving the magnetic flux density in order to reduce hysteresis loss, for example, Patent Document 1 and Patent Document 2 describe that Ni is manufactured when a grain-oriented electrical steel sheet using AlN as an inhibitor is manufactured. Addition and addition of Sb in a predetermined range according to the amount of Ni added, exerts a very strong inhibitory effect on normal grain growth of primary recrystallized grains, improves primary recrystallized grain texture and secondary A technique for significantly reducing iron loss by reducing the average in-plane misalignment angle with respect to the rolling direction of the [110] <001> orientation while reducing the size of recrystallized grains has been disclosed.
一方、渦電流損を低減する方法のうち板厚を低減する方法に関しては、圧延による方法と化学研磨を用いる方法が知られているが、化学研磨で板厚を薄くする方法は、歩留まりの低下が大きく、工業的規模での生産には適さない。そのため、板厚を薄くする方法には、専ら圧延による方法が用いられている。しかし、圧延して板厚を薄くすると、仕上焼鈍における二次再結晶が不安定となり、磁気特性の優れた製品を安定して製造することが難しくなるという問題があった。 On the other hand, regarding the method of reducing the plate thickness among the methods of reducing eddy current loss, a method using rolling and a method using chemical polishing are known, but a method of reducing the plate thickness by chemical polishing reduces the yield. Is not suitable for production on an industrial scale. For this reason, a rolling method is exclusively used as a method for reducing the plate thickness. However, when the sheet thickness is reduced by rolling, there is a problem that secondary recrystallization in finish annealing becomes unstable and it is difficult to stably manufacture a product having excellent magnetic properties.
この問題に対しては、例えば特許文献３に、AlNを主インヒビターとし、強圧下最終冷延を特徴とする薄手一方向性電磁鋼板の製造において、SnとSeの複合添加に加えて、さらにCuおよび／またはSbを添加することにより優れた鉄損値が得られることが記載されている。 To deal with this problem, for example, in Patent Document 3, in the manufacture of a thin unidirectional electrical steel sheet characterized by AlN as a main inhibitor and final cold rolling under high pressure, in addition to the combined addition of Sn and Se, Cu is further added. It is described that an excellent iron loss value can be obtained by adding S and / or Sb.
特許文献４には、板厚0.20mm以下の薄手一方向性電磁鋼板の製造方法において、Nbを添加することによって炭窒化物の微細分散が促進されてインヒビターが強化され、これにより磁気特性が向上することが記載されている。 In Patent Document 4, in the method for producing a thin unidirectional electrical steel sheet having a thickness of 0.20 mm or less, the addition of Nb promotes fine dispersion of carbonitrides and strengthens the inhibitor, thereby improving the magnetic properties. It is described to do.
特許文献５には、熱延板の板厚を薄くし、コイルの巻取温度を下げると共に、仕上焼鈍パターンを適正に制御することで、１回の冷延で磁気特性の優れた薄手一方向性電磁鋼板を製造する方法が記載されている。 In Patent Document 5, the thickness of the hot-rolled sheet is reduced, the coil winding temperature is lowered, and the finish annealing pattern is appropriately controlled to achieve a thin one-way with excellent magnetic properties by one cold rolling. Describes a method for producing a heat-resistant electrical steel sheet.
特許文献６には、熱延コイルの板厚を1.9mm以下とすることで、0.23mm以下の方向性電磁鋼板を一回冷延法で製造する方法が提案されている。 Patent Document 6 proposes a method of producing a directional electrical steel sheet having a thickness of 0.23 mm or less by a single cold rolling method by setting the thickness of a hot-rolled coil to 1.9 mm or less.
特許文献７および８には、スラブにおける(sol.Al/N)と二次再結晶焼鈍時の鋼板板厚ｄの関係を制御すると共に、仕上げ焼鈍において775〜875℃の温度域に40〜200時間保定し、さらに仕上焼鈍の875〜1050℃の温度域における昇温速度を10〜60℃/hに制御することにより、板厚が薄い方向性電磁鋼板において良好な二次再結晶を得る技術が提案されている。
これらの技術の適用により、板厚が薄くても、磁気特性に優れた方向性電磁鋼板の製造が可能になってきた。
In Patent Documents 7 and 8, the relationship between (sol.Al/N) in the slab and the steel sheet thickness d at the time of secondary recrystallization annealing is controlled, and 40 to 200 in the temperature range of 775 to 875 ° C. in finish annealing. Technology for obtaining good secondary recrystallization in grain-oriented electrical steel sheets with thin plate thickness by controlling the temperature rising rate in the temperature range of 875-1050 ° C for finish annealing to 10-60 ° C / h. Has been proposed.
Application of these technologies has made it possible to produce grain-oriented electrical steel sheets with excellent magnetic properties even when the plate thickness is small.
しかしながら、上記のように、仕上焼鈍中に40〜200時間の保定を要する条件では、炉内滞在時間が長くコストが嵩むという課題が残っていた。また、仕上焼鈍中の昇温速度を高めることで焼鈍中のコイル内の温度勾配が大きくなる、つまりコイル中巻部と外巻部とで熱処理履歴に差異が生じ表層粒成長挙動が異なってしまうことにより、コイル内で磁気特性にバラツキが生じるという問題があった。 However, as described above, under the condition that it is necessary to hold for 40 to 200 hours during the finish annealing, there is a problem that the residence time in the furnace is long and the cost is increased. In addition, increasing the heating rate during finish annealing increases the temperature gradient in the coil during annealing, that is, the heat treatment history differs between the coil inner winding and the outer winding, resulting in different surface grain growth behavior. As a result, there is a problem in that the magnetic characteristics vary within the coil.
そこで、発明者らは、板厚が薄い方向性電磁鋼板の二次再結晶が不安定となる原因とその解決策について、鋭意検討を行った。
すなわち、仕上焼鈍途中の鋼板中のインヒビターおよび粒成長挙動を調査した結果、板厚が薄い方向性電磁鋼板において二次再結晶が不安定となる原因は、仕上焼鈍中に粒成長を抑制する役割を持つインヒビターが鋼板表面の酸化に伴い消失することで、表層粒の粗大化が進行するためであることを突き止めた。
Therefore, the inventors diligently studied the cause of the secondary recrystallization of the grain-oriented electrical steel sheet having a small thickness and the solution thereof.
That is, as a result of investigating the inhibitor and grain growth behavior in the steel sheet during finish annealing, the cause of the instability of secondary recrystallization in a grain-oriented electrical steel sheet with a thin plate thickness is the role of suppressing grain growth during finish annealing. It has been found that this is because the coarsening of the surface layer proceeds by the disappearance of the inhibitor having a surface with the oxidation of the steel plate surface.
この結果を受け、発明者らは、板厚の薄い方向性電磁鋼板において二次再結晶を安定化させるためには、仕上焼鈍中に、特に表層におけるインヒビターの劣化を抑制することが重要であると考え、さらに検討を重ねた。
その結果、一次再結晶焼鈍後の鋼板に塗布する焼鈍分離剤中に、硫酸Mgや硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Srおよび硫化Baなどを適量添加することにより、仕上焼鈍中に長時間の保定などの必要なしに安定して二次再結晶が生じることを見出した。この理由は、焼鈍分離剤中に上記したような硫酸化合物を添加すると、かような硫酸化合物が仕上焼鈍中に分解して鋼板内部へＳが侵入し、これによりインヒビター効果が強化され、その結果、表層における粒成長が効果的に抑制されて安定した二次再結晶効果が得られるためであると考えられる。
本発明は、上記の知見に基づいて開発されたものである。
In view of this result, the inventors are required to suppress the deterioration of the inhibitor particularly in the surface layer during finish annealing in order to stabilize the secondary recrystallization in the grain-oriented electrical steel sheet having a small thickness. We thought about this and made further studies.
As a result, by adding an appropriate amount of sulfuric acid Mg, sulfuric acid Ca, sulfuric acid Sr, sulfuric acid Ba, Mg sulfide, Ca sulfide, sulfur sulfide, Ba sulfide, etc. in the annealing separator applied to the steel sheet after the primary recrystallization annealing, It was found that secondary recrystallization occurs stably during the finish annealing without the need for long-term holding. The reason for this is that when a sulfuric acid compound as described above is added to the annealing separator, such a sulfuric acid compound decomposes during the finish annealing and S penetrates into the steel sheet, thereby strengthening the inhibitor effect. This is probably because grain growth in the surface layer is effectively suppressed and a stable secondary recrystallization effect is obtained.
The present invention has been developed based on the above findings.
すなわち、本発明の要旨構成は次のとおりである。
１．Ｃ：0.04〜0.12mass％、Si：1.5〜5.0mass％、Mn：0.01〜1.0mass％、sol.Al：0.010〜0.040mass％、Ｎ：0.004〜0.02mass％、Ｓおよび／またはSe：0.005〜0.05mass％を含有し、残部がFeおよび不可避的不純物からなる鋼スラブを、1250℃以上に加熱したのち、熱間圧延により板厚1.8mm以上の熱延板とし、ついで１回または中間焼鈍を挟む２回以上の冷間圧延により最終板厚0.14〜0.24mmの冷延板とし、一次再結晶焼鈍後、焼鈍分離剤を鋼板に塗布してから仕上焼鈍を施す一連の工程からなる方向性電磁鋼板の製造方法において、
MgOを主成分とする焼鈍分離剤中に、該MgO：100質量部に対し、硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Srおよび硫化Baのうちから選ばれる１種または２種以上を2.0〜20.0質量部添加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. C: 0.04 to 0.12 mass%, Si: 1.5 to 5.0 mass%, Mn: 0.01 to 1.0 mass%, sol.Al: 0.010 to 0.040 mass%, N: 0.004 to 0.02 mass%, S and / or Se: 0.005 to A steel slab containing 0.05 mass% and the balance consisting of Fe and inevitable impurities is heated to 1250 ° C or higher, then hot rolled to a hot rolled sheet with a thickness of 1.8 mm or more, and then subjected to one time or intermediate annealing. A directional electromagnetic consisting of a series of processes in which a cold rolled sheet with a final thickness of 0.14 to 0.24 mm is formed by cold rolling two or more times, and after the primary recrystallization annealing, the annealing separator is applied to the steel sheet and then the finish annealing is performed. In the manufacturing method of the steel sheet,
1 selected from Mg sulfate: Ca sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide, and Ba sulfide in an annealing separator containing MgO as the main component. A method for producing a grain-oriented electrical steel sheet comprising adding 2.0 to 20.0 parts by mass of seeds or two or more seeds.
２．前記鋼スラブが、前記成分に加えてさらに、Sb：0.01〜0.15mass％、Ni：0.10〜1.0mass％、Cu：0.02〜1.0mass％およびMo：0.002〜1.0mass％のうちから選ばれる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に記載の方向性電磁鋼板の製造方法。 2. In addition to the above components, the steel slab is further selected from Sb: 0.01 to 0.15 mass%, Ni: 0.10 to 1.0 mass%, Cu: 0.02 to 1.0 mass%, and Mo: 0.002 to 1.0 mass% Or the manufacturing method of the grain-oriented electrical steel sheet of said 1 characterized by containing 2 or more types.
３．前記鋼スラブが、前記成分に加えてさらに、Ge，Bi，Ｖ，Nb，Te，CrおよびSnのうちから選らばれる１種または２種以上を合計で0.002〜1.0mass％含有することを特徴とする前記１または２に記載の方向性電磁鋼板の製造方法。 3. The steel slab contains 0.002 to 1.0 mass% in total of one or more selected from Ge, Bi, V, Nb, Te, Cr and Sn in addition to the above components. The manufacturing method of the grain-oriented electrical steel sheet according to 1 or 2 above.
４．前記鋼スラブのsol.AlとＮの含有量の比(sol.Al/Ｎ)と、焼鈍分離剤中に添加する硫
酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Srおよび硫化Baのうちから選ばれる１種または２種以上の合計量Ｘ（質量部）および最終板厚ｔ(mm)が下記式を満たす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。
記
３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20
4). The ratio of sol.Al and N content of the steel slab (sol.Al/N) and Mg sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide added to the annealing separator. And the total thickness X (part by mass) and the final thickness t (mm) of one or more kinds selected from Ba sulfide and Ba sulfide satisfy the following formula: A method for producing grain-oriented electrical steel sheets.
3 ≦ (X × t 2 × 1000) / (sol.Al/N) 3 ≦ 20
５．前記冷間圧延以降のいずれかの段階で、磁区細分化処理を施す前記１〜４のいずれかに記載の方向性電磁鋼板の製造方法。 5). The method for producing a grain-oriented electrical steel sheet according to any one of the above 1 to 4, wherein the magnetic domain refinement process is performed at any stage after the cold rolling.
６．前記磁区細分化処理が、二次再結晶焼鈍後の鋼板表面への電子ビーム照射によるものである前記５に記載の方向性電磁鋼板の製造方法。 6). 6. The method for producing a grain-oriented electrical steel sheet according to 5 above, wherein the magnetic domain refinement treatment is performed by electron beam irradiation on the steel sheet surface after the secondary recrystallization annealing.
７．前記磁区細分化処理が、二次再結晶焼鈍後の鋼板表面へのレーザー照射によるものである前記５に記載の方向性電磁鋼板の製造方法。 7). 6. The method for producing a grain-oriented electrical steel sheet according to 5 above, wherein the magnetic domain refinement treatment is performed by laser irradiation on the steel sheet surface after secondary recrystallization annealing.
８．前記磁区細分化処理が、冷間圧延後の鋼板表面への溝形成によるものである前記５に記載の方向性電磁鋼板の製造方法。 8). 6. The method for producing a grain-oriented electrical steel sheet according to 5 above, wherein the magnetic domain refinement treatment is performed by forming a groove on the steel sheet surface after cold rolling.
本発明によれば、仕上焼鈍中に長時間の保定をすることなしに板厚が薄い方向性電磁鋼板の二次再結晶を安定的に得ることが可能となる。また、仕上焼鈍における昇温速度を高める必要がなく、仕上焼鈍中のコイル内での温度勾配が小さいため、コイル内で磁気特性のバラツキが生じないという効果もある。 According to the present invention, secondary recrystallization of a grain-oriented electrical steel sheet having a thin plate thickness can be stably obtained without holding for a long time during finish annealing. In addition, there is no need to increase the rate of temperature increase in finish annealing, and since the temperature gradient in the coil during finish annealing is small, there is an effect that magnetic characteristics do not vary in the coil.
以下、本発明を具体的に説明する。
以下、本発明に至った実験について説明する。
Ｃ：0.07mass％，Si：3.40mass％，Mn：0.08mass％，sol.Al：0.027mass％，Ｎ：0.01mass％，Mo：0.002mass％，Ｓ：0.01mass％，Se：0.02mass％，Ni：0.3mass％，Cu：0.1mass％，Sb：0.06mass％，Sn：0.001mass％およびCr：0.002mass％を含有するスラブを、熱間圧延により板厚2.4mmの熱延コイルとしたのち、1000℃，40秒の熱延板焼鈍を施し、酸洗後、冷間圧延により板厚：1.7mmの中間冷延板とし、1150℃，80秒の中間焼鈍後、200℃での温間圧延により最終板厚：0.17mmの冷延板とした。その後、上記冷延板を脱脂処理したのち、H2：50vol％とN2：50vol％からなる湿水素雰囲気下で、850℃，２分間の脱炭を兼ねた一次再結晶焼鈍を施した。
Hereinafter, the present invention will be specifically described.
Hereinafter, the experiment that led to the present invention will be described.
C: 0.07 mass%, Si: 3.40 mass%, Mn: 0.08 mass%, sol.Al: 0.027 mass%, N: 0.01 mass%, Mo: 0.002 mass%, S: 0.01 mass%, Se: 0.02 mass%, After a slab containing Ni: 0.3 mass%, Cu: 0.1 mass%, Sb: 0.06 mass%, Sn: 0.001 mass% and Cr: 0.002 mass% is hot rolled into a hot rolled coil with a thickness of 2.4 mm Hot-rolled sheet annealed at 1000 ° C for 40 seconds, pickled, cold-rolled to obtain an intermediate cold-rolled sheet with a thickness of 1.7 mm, heated at 1150 ° C for 80 seconds, and then warmed at 200 ° C A cold rolled sheet having a final thickness of 0.17 mm was obtained by rolling. Thereafter, the cold-rolled sheet was degreased, and then subjected to primary recrystallization annealing also serving as decarburization at 850 ° C. for 2 minutes in a wet hydrogen atmosphere composed of H 2 : 50 vol% and N 2 : 50 vol%.
ついで、一次再結晶後の鋼板表面に、表１に示す量の硫酸Mgを添加したMgOを主成分とする焼鈍分離剤を鋼板両面合計で14.0g/m2塗布し、乾燥した。なお、表１に示す硫酸Mg量は、焼鈍分離剤中のMgO：100質量部に対する割合である。ついで、仕上焼鈍として、850℃までをN2雰囲気下で昇温速度20℃/hで加熱し、850℃から1200℃までは25vol％N2-75vol％H2の混合雰囲気下で昇温速度５℃/hで加熱し、1200℃で10時間保持する熱処理を施した。
その後、仕上焼鈍後の鋼板表面から未反応の焼鈍分離剤を除去したのち、リン酸アルミニウムとコロイダルシリカを主成分とする絶縁被膜を形成して、製品コイルとした。
Next, an annealing separator mainly composed of MgO added with the amount of Mg sulfate shown in Table 1 was applied to the surface of the steel sheet after the primary recrystallization at a total of 14.0 g / m 2 on both sides of the steel sheet and dried. In addition, the amount of sulfuric acid Mg shown in Table 1 is a ratio with respect to 100 parts by mass of MgO in the annealing separator. Next, as finish annealing, heat up to 850 ° C under N 2 atmosphere at a heating rate of 20 ° C / h, and from 850 ° C to 1200 ° C under a mixed atmosphere of 25vol% N 2 -75vol% H 2 Heat treatment was performed at 5 ° C./h and maintained at 1200 ° C. for 10 hours.
Then, after removing the unreacted annealing separator from the surface of the steel sheet after the finish annealing, an insulating coating mainly composed of aluminum phosphate and colloidal silica was formed to obtain a product coil.
かくして得られた全長4000mの製品コイルのコイル長手方向０m、1000m、2000m、3000mおよび4000mの計５箇所の位置から、磁気測定用の試験片を採取し、JIS C 2550に記載の方法で、鉄損Ｗ17/50および磁束密度Ｂ8を測定した。
それらの測定値の中で、特性が最も悪い値をコイル内保証値、最も良好な値をコイル内良好値とし、その結果を表１に併記する。
The specimens for magnetic measurement were collected from the total length of the coil length direction of 0m, 1000m, 2000m, 3000m and 4000m of the product coil with a total length of 4000m obtained in this way, and the method described in JIS C 2550 The loss W 17/50 and the magnetic flux density B 8 were measured.
Among these measured values, the worst value is the guaranteed value in the coil, the best value is the good value in the coil, and the results are also shown in Table 1.
表１に示したとおり、焼鈍分離剤中に硫酸Mgを添加することで磁気特性のコイル内保証値および良好値が共に向上した。ただし、焼鈍分離剤中の硫酸Mgが2.0質量部に満たない場合や、20.0質量部を超えた場合には十分な磁気特性の改善効果は認められなかった。 As shown in Table 1, both the guaranteed value in the coil and the good value of the magnetic properties were improved by adding Mg sulfate to the annealing separator. However, when Mg sulfate in the annealing separator was less than 2.0 parts by mass or exceeded 20.0 parts by mass, a sufficient effect of improving magnetic properties was not recognized.
次に、本発明の各構成要件の限定理由について述べる。
Ｃ：0.04〜0.12mass％
Ｃは、熱間圧延、冷間圧延中の組織の均一微細化ならびにGoss方位の発達のために有用な元素であり、少なくとも0.04mass％を含有させる必要がある。しかし、0.12mass％を超えて添加すると、一次再結晶焼鈍で脱炭不足を起こし、磁気特性が劣化するおそれがある。よって、Ｃは0.04〜0.12mass％の範囲とする。好ましくは0.05〜0.10mass％の範囲である。
Next, the reasons for limiting the respective constituent requirements of the present invention will be described.
C: 0.04-0.12 mass%
C is an element useful for uniform refinement of the structure during hot rolling and cold rolling and the development of Goss orientation, and it is necessary to contain at least 0.04 mass%. However, if added over 0.12 mass%, decarburization may be insufficient due to primary recrystallization annealing, and the magnetic properties may deteriorate. Therefore, C is set to a range of 0.04 to 0.12 mass%. Preferably it is the range of 0.05-0.10 mass%.
Si：1.5〜5.0mass％
Siは、鋼板の比抵抗を高めて鉄損の低減に有効に寄与する元素であり、良好な磁気特性を確保する観点から、本発明では1.5mass％以上含有させるものとした。一方、5.0mass％を超える添加は、冷間加工性を著しく害するようになる。よって、Siは1.5〜5.0mass％の範囲とする。好ましくは2.0〜4.0mass％の範囲である。
Si: 1.5-5.0mass%
Si is an element that increases the specific resistance of the steel sheet and contributes effectively to the reduction of iron loss. From the viewpoint of ensuring good magnetic properties, Si is contained in an amount of 1.5 mass% or more in the present invention. On the other hand, the addition exceeding 5.0 mass% significantly impairs cold workability. Therefore, Si is set to a range of 1.5 to 5.0 mass%. Preferably it is the range of 2.0-4.0 mass%.
Mn：0.01〜1.0mass％
Mnは、熱間加工性を改善し、熱間圧延時の表面疵を防止するのに有効な元素であり、この効果を得るためには0.01mass％以上含有させる必要がある。しかし、1.0mass％を超えて添加すると、磁束密度が低下するようになる。よって、Mnは0.01〜1.0mass％の範囲とする。好ましくは0.04〜0.2mass％の範囲である。
Mn: 0.01-1.0mass%
Mn is an element effective for improving hot workability and preventing surface flaws during hot rolling, and in order to obtain this effect, it is necessary to contain 0.01 mass% or more. However, if added over 1.0 mass%, the magnetic flux density decreases. Therefore, Mn is set to a range of 0.01 to 1.0 mass%. Preferably it is the range of 0.04-0.2 mass%.
sol.Al：0.010〜0.040mass％
Alは、インヒビターであるAlNを構成する必須の元素でありが、sol.Alとして0.010mass％未満では、熱延時や熱延板焼鈍の昇温過程等において析出するAlNの量が不足し、十分なインヒビター効果を得ることができない。一方、0.040mass％を超えて添加すると、析出するインヒビターが粗大化し、逆に正常粒成長の抑制力（以下、単に抑制力ともいう）が低下してしまう。よって、AlNのインヒビター効果を十分に得るためには、Alはsol.Alで0.010〜0.040mass％の範囲とする必要がある。好ましくは0.020〜0.030mass％の範囲である。
sol.Al: 0.010 ~ 0.040mass%
Al is an essential element that constitutes the inhibitor AlN, but if it is less than 0.010 mass% as sol.Al, the amount of AlN that precipitates during hot rolling or during the temperature rising process of hot-rolled sheet annealing is sufficient, Inhibitor effect cannot be obtained. On the other hand, when added in excess of 0.040 mass%, the precipitated inhibitor becomes coarse, and conversely, the suppressive power of normal grain growth (hereinafter, also simply referred to as suppressive power) decreases. Therefore, in order to sufficiently obtain the inhibitor effect of AlN, Al needs to be in the range of 0.010 to 0.040 mass% as sol.Al. Preferably it is the range of 0.020-0.030 mass%.
Ｎ：0.004〜0.02mass％
Ｎは、Alと同様、インヒビターであるAlNを構成する必須の元素である。ただし、このＮは、窒化処理を施すことで添加可能なので、スラブ段階では、0.004mass％以上含有していればよい。ただし、窒化処理を施さない場合には0.005mass％以上含有させる必要がある。一方、Ｎを0.02mass％超えて添加した場合には、熱間圧延においてふくれを生じるおそれがある。よって、Ｎは0.004〜0.02mass％の範囲とする。好ましくは0.005〜0.01mass％の範囲である。
N: 0.004 to 0.02 mass%
N, like Al, is an essential element constituting the inhibitor AlN. However, since this N can be added by performing nitriding treatment, it may be contained at 0.004 mass% or more in the slab stage. However, when nitriding is not performed, it is necessary to contain 0.005 mass% or more. On the other hand, when N is added exceeding 0.02 mass%, there is a risk of causing blistering in hot rolling. Therefore, N is set to a range of 0.004 to 0.02 mass%. Preferably it is the range of 0.005-0.01 mass%.
ＳおよびSeの１種または２種合計：0.005〜0.05mass％
ＳおよびSeは、Cu2SやCu2Se等を、AlNと複合して微細析出させ、インヒビターとして利用するために必要な元素である。この目的のため、本発明では、単独もしくは合計で0.005mass％以上を含有させる必要がある。しかし、0.05mass％を超えて添加すると、析出物の粗大化を招く。よって、ＳおよびSeは単独または合計で0.005〜0.05mass％の範囲とする。好ましくは0.01〜0.03mass％の範囲である。
1 type or 2 types total of S and Se: 0.005-0.05 mass%
S and Se are elements necessary for using Cu 2 S, Cu 2 Se, or the like as an inhibitor by being finely precipitated in combination with AlN. For this purpose, in the present invention, it is necessary to contain 0.005 mass% or more alone or in total. However, if added over 0.05 mass%, the precipitate becomes coarse. Therefore, S and Se are made into the range of 0.005-0.05 mass% individually or in total. Preferably it is the range of 0.01-0.03 mass%.
以上、基本成分について説明したが、本発明では、以下に述べる元素を適宜添加することができる。
Sb：0.01〜0.15mass％
Sbは、析出したインヒビターであるAlNやCu2S，Cu2Se，MnS，MnSeの表面に偏析し、インヒビターの粗大化を抑止するために有用な元素である。かかる効果は0.01mass％以上の添加で得られる。しかし、0.15mass％を超えて添加すると、脱炭反応を阻害し、磁気特性の劣化を招くようになる。よって、Sbは0.01〜0.15mass％の範囲とする。好ましくは0.02〜0.10mass％の範囲である。
The basic components have been described above. In the present invention, the following elements can be appropriately added.
Sb: 0.01-0.15mass%
Sb is a useful element for segregating on the surface of precipitated inhibitors AlN, Cu 2 S, Cu 2 Se, MnS, and MnSe, and inhibiting the coarsening of the inhibitor. Such an effect can be obtained by addition of 0.01 mass% or more. However, if added over 0.15 mass%, the decarburization reaction is inhibited and the magnetic properties are deteriorated. Therefore, Sb is set to a range of 0.01 to 0.15 mass%. Preferably it is the range of 0.02-0.10 mass%.
Ni：0.10〜1.0mass％
Niは、粒界にSbと共偏析して、Sbの偏析効果を促進し、インヒビターの粗大化を抑止する元素であるので、0.10mass％以上含有させることが望ましい。しかし、1.0mass％を超えて添加すると、一次再結晶焼鈍後の集合組織が劣化し、磁気特性が低下する原因となる。よって、Niは0.10〜1.0mass％の範囲とする。好ましくは0.10〜0.50mass％の範囲である。
Ni: 0.10-1.0mass%
Ni is an element that co-segregates with Sb at the grain boundary, promotes the segregation effect of Sb, and suppresses the coarsening of the inhibitor, so it is desirable to contain 0.10 mass% or more. However, if added over 1.0 mass%, the texture after the primary recrystallization annealing deteriorates, which causes the magnetic properties to deteriorate. Therefore, Ni is in the range of 0.10 to 1.0 mass%. Preferably it is the range of 0.10-0.50mass%.
Cu：0.02〜1.0mass％
Cuは、Cu2SやCu2Seを構成し、インヒビターを強化するために添加することが望ましい元素である。極薄方向性電磁鋼板においては、インヒビターがMnSやMnSeであると、仕上焼鈍中に抑制力が低下し、二次再結晶が不安定となる。これに対し、インヒビターがCu2S、Cu2Seで、かつNi，Sbと共に複合添加されている場合には、インヒビターの抑制力
は低下し難い。そのため、Cuを0.02mass％以上添加することが好ましい。しかし、1.0mass％を超えて含有させると、インヒビターの粗大化を招くばかりでなく、ふくれの発生を招く。よって、Cuは0.02〜1.0mass％の範囲とする。好ましくは0.04〜0.5mass％の範囲である。
Cu: 0.02 to 1.0 mass%
Cu constitutes Cu 2 S and Cu 2 Se and is an element that is desirably added to strengthen the inhibitor. In an ultrathin grain-oriented electrical steel sheet, if the inhibitor is MnS or MnSe, the suppressive force is reduced during finish annealing, and secondary recrystallization becomes unstable. On the other hand, when the inhibitor is Cu 2 S, Cu 2 Se and is added together with Ni and Sb, the inhibitory power of the inhibitor is unlikely to decrease. Therefore, it is preferable to add Cu by 0.02 mass% or more. However, if the content exceeds 1.0 mass%, not only the inhibitor is coarsened, but also blistering occurs. Therefore, Cu is set to a range of 0.02 to 1.0 mass%. Preferably it is the range of 0.04-0.5 mass%.
Mo：0.002〜1.0mass％
Moは、インヒビターを強化する元素として添加される。しかし、添加量が0.002mass％に満たないとインヒビター強化の効果が小さく、Mo添加の効果が得られにくい。一方、1.0mass％を超えて添加すると二次再結晶が不安定となり磁気特性の劣化を招く。よって、Moは0.002〜1.0mass％の範囲とする。好ましくは0.002〜0.5mass％の範囲、より好ましくは0.05〜0.1mass％の範囲である。
Mo: 0.002 to 1.0 mass%
Mo is added as an element that strengthens the inhibitor. However, if the addition amount is less than 0.002 mass%, the effect of reinforcing the inhibitor is small, and the effect of adding Mo is difficult to obtain. On the other hand, if added over 1.0 mass%, secondary recrystallization becomes unstable, leading to deterioration of magnetic properties. Therefore, Mo is in the range of 0.002 to 1.0 mass%. Preferably it is the range of 0.002-0.5 mass%, More preferably, it is the range of 0.05-0.1 mass%.
本発明では、上記成分に加えてさらに、インヒビター補助成分として、Ge，Bi，Ｖ，Nb，Te，CrおよびSnのうちから選ばれる１種または２種以上を、合計で0.002〜1.0mass％の範囲で含有させることができる。これらの元素は、いずれも析出物を形成し、結晶粒界や析出物の表面に偏析して抑制力を強化する補助的機能を果たす。かかる作用を得るためには、これらの元素を１種または２種類以上の合計で0.002mass％以上含有させる必要がある。しかし、1.0mass％を超える添加は、鋼の脆化や脱炭不良を招くため上限を1.0％とした。よって、上記元素は合計で0.002〜1.0mass％の範囲で含有させるのが好ましい。 In the present invention, in addition to the above-described components, one or more selected from Ge, Bi, V, Nb, Te, Cr and Sn are further added as an inhibitor auxiliary component in a total amount of 0.002 to 1.0 mass%. It can be contained in a range. All of these elements form precipitates and segregate on the grain boundaries and the surface of the precipitates to perform an auxiliary function of strengthening the suppression force. In order to obtain such an action, it is necessary to contain 0.002 mass% or more of these elements in a total of one or more kinds. However, addition exceeding 1.0 mass% causes embrittlement and poor decarburization of the steel, so the upper limit was made 1.0%. Therefore, it is preferable to contain the above elements in the range of 0.002 to 1.0 mass% in total.
焼鈍分離剤中の硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Sr、硫化Baのうちいずれか１種あるいは２種以上の合計添加量：2.0〜20.0質量部
焼鈍分離剤中に添加する硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Sr、硫化Baのうちいずれか１種あるいは２種以上は、仕上焼鈍中の鋼板表層におけるインヒビターを補強するために必須である。通常、方向性電磁鋼板の仕上焼鈍中に、鋼板表面の酸化に伴いインヒビターの消失が進行するために、表層粒の粗大化が進行する。この表層粒粗大化が二次再結晶の発現を不安定にする。この点、焼鈍分離剤中に上記の添加剤（例えば硫酸Mg）が2.0質量部以上存在すれば、焼鈍中に硫酸Mgが分解してＳが鋼板内部に侵入し析出物を生成することで、インヒビターが補強される。しかしながら、添加量が2.0質量部に満たないとその効果が充分に得られず二次再結晶が安定化しない。一方、20.0質量部を超えて添加されると、二次再結晶が発現しないばかりでなく製品板にＳが残留することによる磁気特性の劣化を招くおそれがある。よって、焼鈍分離剤への添加量は2.0〜20.0質量部とした。より好ましくは3.0〜10.0質量部の範囲である。
Total amount of one or more of sulfuric acid Mg, sulfuric acid Ca, sulfuric acid Sr, sulfuric acid Ba, sulfurized Mg, sulfurized Ca, sulfurized Sr, and sulfurized sulfur in the annealing separator: 2.0-20.0 parts by mass Annealing separation One or more of Mg sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide, and Ba sulfide added to the agent reinforces the inhibitor on the surface layer of the steel plate during finish annealing. It is essential to do. Usually, during the finish annealing of the grain-oriented electrical steel sheet, the disappearance of the inhibitor proceeds with the oxidation of the steel sheet surface, so that the coarsening of the surface layer grains proceeds. This coarsening of the surface layer makes the expression of secondary recrystallization unstable. In this respect, if the above-mentioned additive (for example, Mg sulfate) is present in an annealing separator in an amount of 2.0 parts by mass or more, Mg sulfate is decomposed during annealing, and S enters the inside of the steel sheet to generate precipitates. Inhibitors are reinforced. However, if the addition amount is less than 2.0 parts by mass, the effect cannot be sufficiently obtained and secondary recrystallization is not stabilized. On the other hand, if it is added in an amount exceeding 20.0 parts by mass, not only secondary recrystallization will not occur, but also S may remain on the product plate, leading to deterioration of magnetic properties. Therefore, the addition amount to the annealing separator is 2.0 to 20.0 parts by mass. More preferably, it is in the range of 3.0 to 10.0 parts by mass.
(sol.Al/N)と、焼鈍分離剤中に含まれる硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Sr、硫化Baのうちいずれか１種または２種以上の合計量Ｘ(質量部)および最終板厚ｔとが、３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20の関係を満たす
本発明では、前記した成分組成を満たすとともに、酸可溶Alであるsol.Alの含有量とＮの含有量の比と、焼鈍分離剤中に添加する硫化物および板厚との関係が、３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20を満たすことが有利である。このメカニズムについては、必ずしも明らかではないが、発明者らは以下のように推測している。
(sol.Al/N) and any one or more of Mg sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide, and Ba sulfide contained in the annealing separator The total amount X (parts by mass) and the final thickness t satisfy the relationship of 3 ≦ (X × t 2 × 1000) / (sol.Al/N) 3 ≦ 20 In the present invention, the above-described component composition is satisfied. In addition, the relationship between the ratio of the content of sol.Al, which is acid-soluble Al, and the content of N, and the sulfide added to the annealing separator and the plate thickness is 3 ≦ (X × t 2 × 1000) It is advantageous to satisfy /(sol.Al/N) 3 ≦ 20. Although it is not necessarily clear about this mechanism, the inventors have estimated as follows.
板厚に応じて二次再結晶の発現に必要な抑制力が変化し、良好な磁気特性を得るにはそれらを適正な関係に制御する必要がある。これは、特に板厚が薄いほど、表層での結晶粒の粗大化を防ぐことが良好な二次再結晶を得るために重要な因子であるという前述した知見に基づくものである。つまり板厚が薄い場合、良好な二次再結晶を得るためには抑制力が強く保たれる必要がある。スラブ中の成分における(sol.Al/Ｎ)が大きい場合はインヒビターであるAlNが粗大に析出しているために、粒成長抑制力としては弱い。一方で(sol.Al/Ｎ)が小さいとAlNが微細に析出するために粒成長抑制力としては強い。
これに対して、焼鈍分離剤中の硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Sr、硫化Baのうちいずれか１種あるいは２種以上の合計量Ｘに応じて、仕上焼鈍中に鋼板へ侵入するＳ量が増加してインヒビターの補強効果が発現する。以上より、これらのパラメータの間に適正な関係が存在する。
発明者らは、これらの関係について鋭意検討を重ねた結果、これらが３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20の関係を満足させることにより、良好な結果が得られることを突き止めたのである。
The suppression force required for the development of secondary recrystallization varies depending on the plate thickness, and it is necessary to control them in an appropriate relationship in order to obtain good magnetic properties. This is based on the above-described finding that, in particular, the thinner the plate thickness is, the more important factor for obtaining good secondary recrystallization is to prevent the coarsening of crystal grains in the surface layer. That is, when the plate thickness is thin, it is necessary to keep the suppression force strong in order to obtain good secondary recrystallization. When (sol.Al/N) in the components in the slab is large, since the inhibitor AlN is coarsely precipitated, the grain growth inhibiting power is weak. On the other hand, when (sol.Al/N) is small, AlN precipitates finely, so that it is strong as a grain growth inhibiting force.
On the other hand, depending on the total amount X of any one or two or more of Mg sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide, and Ba sulfide in the annealing separator. In addition, the amount of S entering the steel plate during the finish annealing increases, and the reinforcing effect of the inhibitor appears. From the above, an appropriate relationship exists between these parameters.
As a result of intensive studies on these relationships, the inventors have obtained satisfactory results by satisfying the relationship of 3 ≦ (X × t 2 × 1000) / (sol.Al/N) 3 ≦ 20. It has been determined that can be obtained.
次に、本発明の好適製造条件について説明する。
本発明の方向性電磁鋼板の製造方法は、上述した成分組成に調整した鋼スラブを、再加熱後、熱間圧延し、必要に応じて熱延板焼鈍を施したのち、１回または中間焼鈍を挟む２回以上の冷間圧延を施し、一次再結晶焼鈍後、仕上焼鈍を施す一連の工程からなるものである。
上記鋼スラブの製造法については、上述した本発明の成分組成を満たしている限り、特に制限はなく、通常公知の製造条件で製造することができる。
Next, preferred manufacturing conditions of the present invention will be described.
The method for producing a grain-oriented electrical steel sheet according to the present invention includes a steel slab adjusted to the above-described component composition, re-heated, hot-rolled, and subjected to hot-rolled sheet annealing as necessary, once or intermediate annealing. It is composed of a series of processes in which cold rolling is performed twice or more, and after the primary recrystallization annealing, finish annealing is performed.
There is no restriction | limiting in particular about the manufacturing method of the said steel slab, as long as the component composition of this invention mentioned above is satisfy | filled, It can manufacture on a well-known manufacturing condition normally.
上記鋼スラブは、その後、1250℃以上の温度に再加熱した後、熱間圧延に供する。再加熱温度が1250℃未満では、添加した元素が鋼中に固溶しないからである。なお、再加熱する方法は、ガス炉、誘導加熱炉、通電炉などの公知の方法を用いることができる。また、熱間圧延の条件は、従来公知の条件であればよく、特に制限はない。 The steel slab is then reheated to a temperature of 1250 ° C. or higher and then subjected to hot rolling. This is because when the reheating temperature is less than 1250 ° C., the added element does not dissolve in the steel. In addition, the method of reheating can use well-known methods, such as a gas furnace, an induction heating furnace, and an electric furnace. Moreover, the conditions of hot rolling should just be conventionally well-known conditions, and there is no restriction | limiting in particular.
上記スラブの再加熱後、熱間圧延により板厚1.8mm以上の熱延板とする。ここで、熱延板の板厚を1.8mm以上に限定する理由は、圧延時間を短縮し、熱延鋼板の圧延方向の温度差を低減させるためである。なお、熱間圧延の条件は、常法に準じて行えばよく、特に制限はない。 After reheating the slab, a hot rolled sheet having a thickness of 1.8 mm or more is formed by hot rolling. Here, the reason for limiting the thickness of the hot-rolled sheet to 1.8 mm or more is to shorten the rolling time and reduce the temperature difference in the rolling direction of the hot-rolled steel sheet. In addition, the hot rolling conditions may be performed according to a conventional method, and there is no particular limitation.
熱間圧延して得た熱延板は、その後、必要に応じて熱延板焼鈍を施したのち、酸洗し、１回または中間焼鈍を挟む２回以上の冷間圧延によって最終板厚の冷延板とする。
上記熱延板焼鈍および中間焼鈍は、熱間圧延や冷間圧延で導入された歪を利用して再結晶せるため、800℃以上の温度で行うことが好ましい。また、上記焼鈍における冷却を、急速冷却とし、鋼中の固溶Ｃ量を高めることは、二次再結晶の核生成頻度を高める効果があるので好ましい。また、急速冷却した後、所定の温度範囲で保定することは、微細カーバイドを鋼中に析出させ上記効果を高めるのでより好ましい。
なお、上記の冷間圧延では、パス間時効や温間圧延を適用してもよいことは勿論である。さらに、上記冷延板は、一次再結晶焼鈍する前に、製品板の鉄損を低減するため、鋼板表面にエッチングで溝を形成する磁区細分化処理を施してもよい。また、上記冷延板は、二次再結晶させる前までに、公知の磁区細分化処理、たとえば微細結晶粒を生成させるための点線状の局所的熱処理や化学的処理を施してもよい。
The hot-rolled sheet obtained by hot rolling is then subjected to hot-rolled sheet annealing as necessary, and then pickled, and the final sheet thickness is obtained by cold rolling at least once with one or intermediate annealing in between. Cold-rolled sheet.
The hot-rolled sheet annealing and intermediate annealing are preferably performed at a temperature of 800 ° C. or higher in order to recrystallize using strain introduced by hot rolling or cold rolling. Moreover, it is preferable to set the cooling in the annealing to rapid cooling and increase the amount of dissolved C in the steel because it has an effect of increasing the nucleation frequency of secondary recrystallization. Moreover, it is more preferable to hold | maintain in a predetermined temperature range after rapid cooling, since a fine carbide precipitates in steel and the said effect is heightened.
Of course, in the above cold rolling, aging between passes or warm rolling may be applied. Furthermore, before the primary recrystallization annealing, the cold-rolled plate may be subjected to a magnetic domain refinement process in which grooves are formed by etching on the steel plate surface in order to reduce iron loss of the product plate. Further, the cold-rolled plate may be subjected to a known magnetic domain refinement process, for example, a dotted-line local heat treatment or a chemical process for generating fine crystal grains, before secondary recrystallization.
最終板厚とした冷延板は、脱脂処理し、脱炭焼鈍を兼ねた一次再結晶焼鈍を施す。さらに、一次再結晶焼鈍では、必要に応じて窒化処理を兼ねて行ってもよく、また一次再結晶焼鈍とは別に、冷間圧延後から仕上焼鈍前までの間に窒化処理工程を付加してもよい。
上記に加えて、一次再結晶焼鈍の加熱過程における200〜700℃間の昇温速度を50℃/s以上とすることにより、一次再結晶板集合組織におけるGoss方位粒の数を増加させ、二次再結晶粒を細粒化することができるので、鉄損特性をさらに改善することができる。
The cold-rolled sheet having the final thickness is degreased and subjected to primary recrystallization annealing that also serves as decarburization annealing. Furthermore, in the primary recrystallization annealing, it may be performed as a nitriding treatment if necessary. In addition to the primary recrystallization annealing, a nitriding treatment step is added between the cold rolling and before the finish annealing. Also good.
In addition to the above, by increasing the heating rate between 200-700 ° C. in the heating process of primary recrystallization annealing to 50 ° C./s or more, the number of Goss orientation grains in the primary recrystallization plate texture is increased, Since the next recrystallized grains can be made finer, the iron loss characteristics can be further improved.
また、鋼板表面に塗布する焼鈍分離剤は、前述した硫化物以外は公知のものを用いることができる。
すなわち、MgOを主成分とし、これに対し、必要に応じてTiO2やSnO、SnO2、Sb2O3等を0.1〜15質量部の範囲で添加したものを用いることができる。
また、かかる焼鈍分離剤の塗布量は、鋼板両面合計で５〜30g/m2程度とすることが好ましい。
Moreover, as the annealing separator applied to the steel plate surface, known ones other than the sulfides described above can be used.
That is, it is possible to use a material containing MgO as a main component and adding TiO 2 , SnO, SnO 2 , Sb 2 O 3 or the like in a range of 0.1 to 15 parts by mass as necessary.
Moreover, it is preferable that the application quantity of this annealing separation agent shall be about 5-30 g / m < 2 > in the steel plate both surface total.
仕上焼鈍は、通常、二次再結晶焼鈍と純化焼鈍を兼ねて、最高1200℃程度の温度で行われる。
二次再結晶は、通常1000℃程度で発現するが、二次再結晶が完了するまでの焼鈍雰囲気は窒素雰囲気や水素雰囲気やアルゴン雰囲気あるいはこれらの混合雰囲気であることが望ましい。これは二次再結晶焼鈍中に鋼板を過度に酸化させないためである。なお、本発明においては、従来の極薄方向性電磁鋼板の二次再結晶焼鈍のように、必ずしも特許文献５のように加熱速度を10℃/h〜60℃/hに制御する必要はない。ただし、60℃/hを超える場合は、二次再結晶粒のGoss方位への先鋭度の低下を招く可能性があるので、60℃/h以下であることが望ましい。また、５℃/h以下の昇温速度では炉内滞在時間を不必要に伸ばすことになるので、５℃/h以上であることが望ましい。
また、二次再結晶完了後に1200℃程度の高温域において水素雰囲気中で３〜10時間の保定を行うことが望ましい。３時間以下では鋼板の純化反応が充分でなく、磁気特性の劣化を招くし、10時間以上となるとコイルの形状が悪化する原因となる。また、保定を終えた後の冷却時における焼鈍雰囲気は水素雰囲気やアルゴン雰囲気あるいはこれらの混合雰囲気であることが望ましい。これは過度な酸化を防止するとともに、鋼板の窒化を防止するためである。
The finish annealing is usually performed at a temperature of about 1200 ° C. at the maximum for both secondary recrystallization annealing and purification annealing.
Secondary recrystallization usually appears at about 1000 ° C., but the annealing atmosphere until the completion of secondary recrystallization is preferably a nitrogen atmosphere, a hydrogen atmosphere, an argon atmosphere, or a mixed atmosphere thereof. This is because the steel sheet is not excessively oxidized during the secondary recrystallization annealing. In the present invention, it is not always necessary to control the heating rate to 10 ° C./h to 60 ° C./h as in Patent Document 5 as in the secondary recrystallization annealing of the conventional ultrathin grain-oriented electrical steel sheet. . However, when it exceeds 60 ° C./h, there is a possibility that the sharpness of the secondary recrystallized grains in the Goss orientation will be lowered, so that it is preferably 60 ° C./h or less. Further, since the staying time in the furnace is unnecessarily extended at a heating rate of 5 ° C./h or less, it is desirable that the temperature is 5 ° C./h or more.
In addition, it is desirable to hold for 3 to 10 hours in a hydrogen atmosphere in a high temperature range of about 1200 ° C. after the completion of secondary recrystallization. If the time is less than 3 hours, the steel plate is not sufficiently purified, leading to deterioration of magnetic properties, and if it is longer than 10 hours, the shape of the coil deteriorates. Moreover, it is desirable that the annealing atmosphere at the time of cooling after finishing the holding is a hydrogen atmosphere, an argon atmosphere, or a mixed atmosphere thereof. This is for preventing excessive oxidation and preventing nitriding of the steel sheet.
仕上焼鈍した鋼板は、その後、鋼板表面に残存する未反応の焼鈍分離剤を除去した後、必要に応じて、絶縁コーティングを塗布・焼付けたり、平坦化焼鈍を施したりして製品板とする。上記絶縁コーティングは、鉄損を低減するためには、張力コーティングを用いることが好ましい。
また、仕上焼鈍後の鋼板に、鉄損を低減するため、プラズマジェットやレーザー照射、電子ビーム照射を線状に施したり、突起状ロールで線状の歪を付与したりする公知の磁区細分化処理を施してもよい。さらに、仕上焼鈍により鋼板表面に形成されるフォルステライト被膜を酸洗や研磨により除去したのち、鋼板表面を電解や化学研磨などにより鏡面化し、さらに張力コーティングを施して製品板としてもよい。
Then, after finishing the unreacted annealing separator remaining on the surface of the steel sheet, the finish-annealed steel sheet is coated with an insulating coating or baked or flattened annealed as necessary to obtain a product plate. The insulating coating is preferably a tension coating in order to reduce iron loss.
In addition, in order to reduce iron loss to the steel sheet after finish annealing, a known magnetic domain subdivision is applied in which a plasma jet, laser irradiation, or electron beam irradiation is linearly applied, or linear distortion is imparted by a protruding roll. Processing may be performed. Furthermore, after removing the forsterite film formed on the steel plate surface by finish annealing by pickling or polishing, the steel plate surface may be mirror-finished by electrolysis or chemical polishing, and further coated with tension to form a product plate.
実施例１（焼鈍分離剤へ添加する硫化物の種類）
Ｃ：0.06mass％，Si：3.30mass％，Mn：0.06mass％，sol.Al：0.027mass％，Ｎ：0.008mass％，Ｓ：0.02mass％，Se：0.01mass％，Ni：0.3mass％，Cu：0.1mass％，Sb：0.07mass％，Mo：0.005mass％，Bi：0.001mass％およびＶ：0.001mass％を含有するスラブを、熱間圧延により板厚2.4mmの熱延コイルとしたのち、1000℃×40秒の熱延板焼鈍を施し、酸洗後、冷間圧延により板厚：1.7mmの中間冷延板とし、1150℃×80秒の中間焼鈍後、200℃での温間圧延により最終板厚を0.20mmの冷延板とした。
その後、上記冷延板を脱脂処理し、H2：50vol％とN2：50vol％からなる湿水素雰囲気下で850℃，２分間の脱炭を兼ねた一次再結晶焼鈍を施した。
ついで、一次再結晶後の鋼板表面に、表２に示す硫化物をMgOを主成分とする焼鈍分離剤中に種々の割合で添加したものを鋼板両面合計で14.0g/m2塗布し、乾燥した。仕上焼鈍として、850℃までをN2雰囲気下で昇温速度20℃/hで加熱し、850℃から1200℃までは25vol％N2-75vol％H2の混合雰囲気下で昇温速度10℃/hで加熱し、1200℃に10時間保持する熱処理を施した。
Example 1 (type of sulfide added to annealing separator)
C: 0.06 mass%, Si: 3.30 mass%, Mn: 0.06 mass%, sol.Al: 0.027 mass%, N: 0.008 mass%, S: 0.02 mass%, Se: 0.01 mass%, Ni: 0.3 mass%, After a slab containing Cu: 0.1 mass%, Sb: 0.07 mass%, Mo: 0.005 mass%, Bi: 0.001 mass% and V: 0.001 mass% is hot rolled into a hot rolled coil having a thickness of 2.4 mm , Hot-rolled sheet annealed at 1000 ℃ for 40 seconds, pickled, cold-rolled to obtain an intermediate cold-rolled sheet with a thickness of 1.7mm, after intermediate annealing at 1150 ℃ for 80 seconds, warm at 200 ℃ A cold-rolled sheet having a final thickness of 0.20 mm was obtained by rolling.
Thereafter, the cold-rolled sheet was degreased and subjected to primary recrystallization annealing that also served as decarburization at 850 ° C. for 2 minutes in a wet hydrogen atmosphere composed of H 2 : 50 vol% and N 2 : 50 vol%.
Next, 14.0 g / m 2 of steel sheet in total was added to the surface of the steel sheet after the primary recrystallization, and the sulfides shown in Table 2 were added in various proportions to an annealing separator mainly composed of MgO, and dried. did. As finish annealing, heating up to 850 ° C under N 2 atmosphere at a heating rate of 20 ° C / h, and from 850 ° C to 1200 ° C, heating rate of 10 ° C in a mixed atmosphere of 25vol% N 2 -75vol% H 2 A heat treatment was performed by heating at 1200 h and holding at 1200 ° C. for 10 hours.
ついで、仕上焼鈍後の鋼板表面から未反応の焼鈍分離剤を除去した後、リン酸アルミニウムとコロイダルシリカを主成分とする絶縁被膜を被成したのち、電子ビームを、加速電圧：80kV、照射間隔：４mm、ビーム電流：３mAの条件で圧延直角方向に連続照射して製品コイルとした。 Next, after removing the unreacted annealing separator from the surface of the steel sheet after the finish annealing, an insulating film composed mainly of aluminum phosphate and colloidal silica is formed, and then an electron beam is applied with an acceleration voltage of 80 kV and an irradiation interval. : 4 mm, beam current: 3 mA. Continuous irradiation in the direction perpendicular to the rolling direction was used as a product coil.
かくして得られた全長4000mの製品コイルのコイル長手方向０m、1000m、2000m、3000mおよび4000mの計５箇所の位置から、磁気測定用の試験片を採取し、JIS C 2550に記載の方法で、鉄損Ｗ17/50および磁束密度Ｂ8を測定した。
それらの測定値の中で、特性が最も悪い値をコイル内保証値、最も良好な値をコイル内良好値とし、その結果を表２に併記する。
The specimens for magnetic measurement were collected from the total length of the coil length direction of 0m, 1000m, 2000m, 3000m and 4000m of the product coil with a total length of 4000m obtained in this way, and the method described in JIS C 2550 The loss W 17/50 and the magnetic flux density B 8 were measured.
Among these measured values, the worst value is the guaranteed value in the coil, the best value is the good value in the coil, and the results are also shown in Table 2.
表２に示したとおり、焼鈍分離剤中に硫化物を添加しなかった場合に比べ、焼鈍分離剤中に硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Srおよび硫化Baのうちいずれか１種あるいは２種以上の合計で2.0〜20.0質量部添加した場合には良好な磁気特性を得ることができた。 As shown in Table 2, Mg, Sulfuric acid, Ca, Sr, Sr, Ba, Sulfur, Ca, Sr and Sulfur were added to the annealing separator compared to the case where no sulfide was added to the annealing separator. In the case where 2.0 to 20.0 parts by mass of any one or two or more of Ba were added, good magnetic properties could be obtained.
実施例２（最終板厚に対する適正な焼鈍分離剤中の硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Sr、硫化Baのうちいずれか１種あるいは２種以上の合計量）
Ｃ：0.07mass％，Si：3.40mass％，Mn：0.07mass％，sol.Al：0.025mass％，Ｎ：0.01mass％，Ｓ：0.02mass％，Se：0.01mass％，Ni：0.3mass％，Cu：0.1mass％，Sb：0.07mass％，Mo：0.002mass％およびGe：0.002mass％を含有するスラブを、熱間圧延により板厚2.4mmの熱延コイルとしたのち、1000℃，40秒の熱延板焼鈍を施し、酸洗後、冷間圧延により板厚：1.7mmの中間冷延板とし、1150℃×80秒の中間焼鈍後、200℃での温間圧延により最終板厚がそれぞれ0.14、0.17，0.20，0.24mmの冷延板とした。
その後、上記冷延板を脱脂処理し、H2：50vol％とN2：50vol％からなる湿水素雰囲気下で850℃×２分間の脱炭を兼ねた一次再結晶焼鈍を施した。
次いで、一次再結晶後の鋼板表面に、それぞれの板厚に対し表３に示す量の硫酸Mgを添加したMgOを主成分とする焼鈍分離剤を鋼板両面合計で14.0g/m2塗布し、乾燥した。仕上焼鈍として、850℃までをN2雰囲気下で昇温速度20℃/hで加熱し、850℃から1200℃までは25vol％N2-75vol％H2の混合雰囲気下で昇温速度20℃/hで加熱し、1200℃に10時間保持する熱処理を施した。
Example 2 (total of any one or more of Mg sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide, and Ba sulfide in an appropriate annealing separator for the final thickness) amount)
C: 0.07 mass%, Si: 3.40 mass%, Mn: 0.07 mass%, sol.Al: 0.025 mass%, N: 0.01 mass%, S: 0.02 mass%, Se: 0.01 mass%, Ni: 0.3 mass%, A slab containing Cu: 0.1 mass%, Sb: 0.07 mass%, Mo: 0.002 mass%, and Ge: 0.002 mass% was hot rolled into a hot rolled coil with a thickness of 2.4 mm, and then 1000 ° C for 40 seconds. After hot-rolled sheet annealing, pickling and cold rolling to obtain an intermediate cold-rolled sheet with a thickness of 1.7 mm, after intermediate annealing at 1150 ° C x 80 seconds, the final sheet thickness is obtained by warm rolling at 200 ° C. Cold-rolled sheets of 0.14, 0.17, 0.20, and 0.24 mm were used, respectively.
Thereafter, the cold-rolled sheet was degreased and subjected to primary recrystallization annealing that also served as decarburization at 850 ° C. for 2 minutes in a wet hydrogen atmosphere composed of H 2 : 50 vol% and N 2 : 50 vol%.
Next, 14.0 g / m 2 of a steel sheet on both sides of an annealing separator mainly composed of MgO added with sulfuric acid Mg in an amount shown in Table 3 with respect to each sheet thickness was applied to the surface of the steel sheet after primary recrystallization. Dried. As finish annealing, heat up to 850 ° C in N 2 atmosphere at a heating rate of 20 ° C / h, and from 850 ° C to 1200 ° C in a mixed atmosphere of 25vol% N 2 -75vol% H 2 at a heating rate of 20 ° C A heat treatment was performed by heating at 1200 h and holding at 1200 ° C. for 10 hours.
ついで、仕上焼鈍後の鋼板表面から未反応の焼鈍分離剤を除去したのち、リン酸アルミニウムとコロイダルシリカを主成分とする絶縁被膜を形成し、製品コイルとした。
かくして得られた全長4000mの製品コイルのコイル長手方向０m、1000m、2000m、3000mおよび4000mの計５箇所の位置から、磁気測定用の試験片を採取し、JIS C 2550に記載の方法で、鉄損Ｗ17/50および磁束密度Ｂ8を測定した。
それらの測定値の中で、特性が最も悪い値をコイル内保証値、最も良好な値をコイル内良好値とし、その結果を表３に併記する。
Next, after removing the unreacted annealing separator from the surface of the steel sheet after the finish annealing, an insulating film mainly composed of aluminum phosphate and colloidal silica was formed to obtain a product coil.
The specimens for magnetic measurement were collected from the total length of the coil length direction of 0m, 1000m, 2000m, 3000m and 4000m of the product coil with a total length of 4000m obtained in this way, and the method described in JIS C 2550 The loss W 17/50 and the magnetic flux density B 8 were measured.
Among these measured values, the worst value is the guaranteed value in the coil, the best value is the good value in the coil, and the results are also shown in Table 3.
表３に示したとおり、いずれの最終板厚においても焼鈍分離剤中に硫酸Mgを２〜20質量部添加した場合には良好な磁気特性を得ることができた。
さらに、３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20を満たす条件では特に磁気特性は良好で、なおかつコイル内保証値と良好値の差も小さく、安定して磁気特性に優れたコイルを得ることができた。一方で、硫酸Mgを添加しなかった条件や20.0質量部を超えて添加した条件においては良好な二次再結晶が得られず、磁気特性不良となった。
As shown in Table 3, good magnetic properties could be obtained when 2 to 20 parts by mass of Mg sulfate was added to the annealing separator at any final thickness.
Furthermore, the magnetic properties are particularly good under the conditions satisfying 3 ≦ (X × t 2 × 1000) / (sol.Al/N) 3 ≦ 20, and the difference between the guaranteed value in the coil and the good value is small and stable. A coil with excellent magnetic properties could be obtained. On the other hand, good secondary recrystallization could not be obtained under the conditions in which Mg sulfate was not added or in excess of 20.0 parts by mass, resulting in poor magnetic properties.
実施例３（スラブ成分と焼鈍分離剤中の硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Sr、硫化Baのうちいずれか１種あるいは２種以上の合計量の関係）
表４に示す成分組成になるスラブを、熱間圧延により板厚2.2mmの熱延コイルとしたのち、1000℃，40秒の熱延板焼鈍を施し、酸洗後、冷間圧延により板厚：1.7mmの中間冷延板とし、1150℃，80秒の中間焼鈍後、200℃の温間圧延により最終板厚を0.19mmの冷延板とした。この冷延板に対し、鋼板表面に、幅：180μm、深さ：15μmで、圧延直角方向に延びる溝を圧延方向に５mmの間隔で形成する磁区細分化処理を施した。
ついで、H2：50vol％とN2：50vol％からなる湿水素雰囲気下で、850℃，２分間の脱炭を兼ねた一次再結晶焼鈍を施した。
ついで、一次再結晶後の鋼板表面に、表４に示す量の硫酸Mgを添加したMgOを主成分とする焼鈍分離剤を鋼板両面合計で14.0g/m2塗布し、乾燥した。その後、仕上焼鈍として、850℃までをN2雰囲気下で昇温速度20℃/hで加熱し、850℃から1200℃までは25vol％N2-75vol％H2の混合雰囲気下で昇温速度10℃/hで加熱し、1200℃に10時間保持する熱処理を施した。
Example 3 (Relationship between slab component and total amount of one or more of Mg sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide, and Ba sulfide in annealing separator) )
A slab having the composition shown in Table 4 was hot rolled into a hot rolled coil with a thickness of 2.2 mm, then subjected to hot rolled sheet annealing at 1000 ° C. for 40 seconds, pickled, and then cold rolled to obtain a plate thickness. : 1.7 mm intermediate cold-rolled sheet, after intermediate annealing at 1150 ° C. for 80 seconds, warm rolled at 200 ° C. to obtain a cold-rolled sheet having a final thickness of 0.19 mm. This cold-rolled sheet was subjected to a magnetic domain refinement process in which a groove having a width of 180 μm and a depth of 15 μm and extending in the direction perpendicular to the rolling was formed at intervals of 5 mm in the rolling direction.
Subsequently, primary recrystallization annealing was performed in a wet hydrogen atmosphere composed of H 2 : 50 vol% and N 2 : 50 vol%, which also served as decarburization at 850 ° C. for 2 minutes.
Next, an annealing separator mainly composed of MgO added with the amount of Mg sulfate shown in Table 4 was applied to the steel plate surface after the primary recrystallization at a total of 14.0 g / m 2 on both sides of the steel plate and dried. Then, as finish annealing, heat up to 850 ° C under N 2 atmosphere at a heating rate of 20 ° C / h, and from 850 ° C to 1200 ° C under a mixed atmosphere of 25vol% N 2 -75vol% H 2 Heat treatment was performed at 10 ° C / h and maintained at 1200 ° C for 10 hours.
ついで、仕上焼鈍後の鋼板表面から未反応の焼鈍分離剤を除去したのち、リン酸アルミニウムとコロイダルシリカを主成分とする絶縁被膜を形成し、製品コイルとした。
かくして得られた全長4000mの製品コイルのコイル長手方向０m、1000m、2000m、3000mおよび4000mの計５箇所の位置から、磁気測定用の試験片を採取し、JIS C 2550に記載の方法で、鉄損Ｗ17/50および磁束密度Ｂ8を測定した。
それらの測定値の中で、特性が最も悪い値をコイル内保証値、最も良好な値をコイル内良好値とし、その結果を表４に併記する。
Next, after removing the unreacted annealing separator from the surface of the steel sheet after the finish annealing, an insulating film mainly composed of aluminum phosphate and colloidal silica was formed to obtain a product coil.
The specimens for magnetic measurement were collected from the total length of the coil length direction of 0m, 1000m, 2000m, 3000m and 4000m of the product coil with a total length of 4000m obtained in this way, and the method described in JIS C 2550 The loss W 17/50 and the magnetic flux density B 8 were measured.
Among these measured values, the worst value is the guaranteed value in the coil, the best value is the good value in the coil, and the results are also shown in Table 4.
表４から明らかなように、焼鈍分離剤中に適量の硫酸Mgを添加することで良好な磁気特性が得られることが分かる。また、特に焼鈍分離剤中の硫酸Mg量Ｘと各々のスラブ成分に対して３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20の関係を満たす条件では特に磁気特性は良好で、かつコイル内保証値と良好値の差も小さく、安定して磁気特性に優れたコイルを得ることができた。さらに、スラブ成分で、Ni：0.1〜1.0mass％、Cu：0.02〜1.0mass％およびSb：0.01〜0.15mass％のうちから選ばれる１種または２種以上を含有する条件では、特に良好な磁気特性が得られた。 As is apparent from Table 4, it can be seen that good magnetic properties can be obtained by adding an appropriate amount of Mg sulfate to the annealing separator. In particular, the magnetic properties are especially satisfied under the condition satisfying the relationship of 3 ≦ (X × t 2 × 1000) / (sol.Al/N) 3 ≦ 20 for the Mg amount of sulfuric acid X in the annealing separator and each slab component. In addition, the difference between the guaranteed value in the coil and the good value was small, and a coil having excellent magnetic characteristics could be obtained stably. Furthermore, the magnetic properties are particularly good under the condition that the slab component contains one or more selected from Ni: 0.1 to 1.0 mass%, Cu: 0.02 to 1.0 mass%, and Sb: 0.01 to 0.15 mass%. Characteristics were obtained.
実施例４（板厚に対する発明の効果確認）
Ｃ：0.065mass％，Si：3.40mass％，Mn：0.08mass％，sol.Al：0.027mass％，Ｎ：0.010mass％，Ｓ：0.03mass％，Se：0.01mass％，Ni：0.3mass％，Cu：0.1mass％，Sb：0.07mass％，Mo：0.002mass％を含有し、残部はFeおよび不可避的不純物からなるスラブを、熱間圧延により板厚2.4mmの熱延コイルとしたのち、1000℃，40秒の熱延板焼鈍を施し、酸洗後、冷間圧延により板厚：1.7mmの中間冷延板とし、1150℃×80秒の中間焼鈍後、200℃での温間圧延により最終板厚がそれぞれ0.17，0.20，0.23，0.27，0.30mmの冷延板とした。
その後、上記冷延板を脱脂処理し、H2：50vol％とN2：50vol％からなる湿水素雰囲気下で850℃×２分間の脱炭を兼ねた一次再結晶焼鈍を施した。
次いで、一次再結晶後の鋼板表面に、それぞれの板厚に対し表５に示す量の硫酸Mgを添加したMgOを主成分とする焼鈍分離剤を鋼板両面合計で14.0g/m2塗布し、乾燥した。仕上焼鈍として、850℃までをN2雰囲気下で昇温速度30℃/hで加熱し、850℃から1200℃までは25vol％N2-75vol％H2の混合雰囲気下で昇温速度15℃/hで加熱し、1200℃に５時間保持する熱処理を施した。
Example 4 (Confirmation of effect of invention on plate thickness)
C: 0.065 mass%, Si: 3.40 mass%, Mn: 0.08 mass%, sol.Al: 0.027 mass%, N: 0.010 mass%, S: 0.03 mass%, Se: 0.01 mass%, Ni: 0.3 mass%, Cu: 0.1mass%, Sb: 0.07mass%, Mo: 0.002mass%, the balance slab consisting of Fe and inevitable impurities was hot rolled into a hot rolled coil with a thickness of 2.4mm, then 1000 ℃, hot-rolled sheet annealed for 40 seconds, pickled, cold rolled to a sheet thickness of 1.7mm, cold-rolled sheet with intermediate thickness of 1150 ℃ x 80 seconds, then warm-rolled at 200 ℃ Cold-rolled sheets with final sheet thicknesses of 0.17, 0.20, 0.23, 0.27, and 0.30 mm were used.
Thereafter, the cold-rolled sheet was degreased and subjected to primary recrystallization annealing that also served as decarburization at 850 ° C. for 2 minutes in a wet hydrogen atmosphere composed of H 2 : 50 vol% and N 2 : 50 vol%.
Next, the surface of the steel sheet after the primary recrystallization was coated with 14.0 g / m 2 of an annealing separator mainly composed of MgO added with Mg sulfate in an amount shown in Table 5 for each sheet thickness. Dried. As finish annealing, heat up to 850 ° C in N 2 atmosphere at a heating rate of 30 ° C / h, and from 850 ° C to 1200 ° C, the heating rate is 15 ° C in a mixed atmosphere of 25 vol% N 2 -75 vol% H 2 A heat treatment was performed by heating at 1200 ° C. and holding at 1200 ° C. for 5 hours.
ついで、仕上焼鈍後の鋼板表面から未反応の焼鈍分離剤を除去したのち、リン酸アルミニウムとコロイダルシリカを主成分とする絶縁被膜を形成し、製品コイルとした。
かくして得られた全長4000mの製品コイルのコイル長手方向０m、1000m、2000m、3000mおよび4000mの計５箇所の位置から、磁気測定用の試験片を採取し、JIS C 2550に記載の方法で、鉄損Ｗ17/50および磁束密度Ｂ8を測定した。
それらの測定値の中で、特性が最も悪い値をコイル内保証値、最も良好な値をコイル内良好値とし、その結果を表５に併記する。
また、図１に、硫酸Mgを最適範囲〔(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3が３〜20を満たす範囲〕で添加した場合における板厚と鉄損改善代との関係について調べた結果を示す。
Next, after removing the unreacted annealing separator from the surface of the steel sheet after the finish annealing, an insulating film mainly composed of aluminum phosphate and colloidal silica was formed to obtain a product coil.
The specimens for magnetic measurement were collected from the total length of the coil length direction of 0m, 1000m, 2000m, 3000m and 4000m of the product coil with a total length of 4000m obtained in this way, and the method described in JIS C 2550 The loss W 17/50 and the magnetic flux density B 8 were measured.
Among these measured values, the worst value is the guaranteed value in the coil, the best value is the good value in the coil, and the results are also shown in Table 5.
In addition, FIG. 1 shows the plate thickness and the iron loss improvement allowance when Mg sulfate is added in the optimum range [(X × t 2 × 1000) / (sol.Al/N) 3 satisfies 3 to 20]. The result of having investigated about the relationship of is shown.
表５に示したとおり、焼鈍分離剤中の硫酸Mg量Ｘが３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20の関係を満たす場合、すなわち硫酸Mgを最適範囲で添加した場合には、磁気特性は良好で、かつコイル内保証値と良好値の差も小さく、安定して磁気特性に優れたコイルを得ることができた。
ただし、図１に示したように、板厚が0.27mm以上の場合は鉄損の改善代が小さい。
As shown in Table 5, when the amount of sulfuric acid Mg in the annealing separator satisfies the relationship of 3 ≦ (X × t2 × 1000) / (sol.Al/N) 3 ≦ 20, that is, the sulfuric acid Mg is within the optimum range. When added, the magnetic characteristics were good, and the difference between the guaranteed value in the coil and the good value was small, and a coil having excellent magnetic characteristics was stably obtained.
However, as shown in FIG. 1, when the plate thickness is 0.27 mm or more, the margin for improving the iron loss is small.
Claims (7)
MgOを主成分とする焼鈍分離剤中に、該MgO：100質量部に対し、硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Srおよび硫化Baのうちから選ばれる１種または２種以上を2.0〜20.0質量部添加し、前記鋼スラブのsol.AlとＮの含有量の比(sol.Al/Ｎ)と、前記焼鈍分離剤中に添加する硫酸Mg、硫酸Ca、硫酸Sr、硫酸Ba、硫化Mg、硫化Ca、硫化Srおよび硫化Baのうちから選ばれる１種または２種以上の合計量Ｘ（質量部）および前記最終板厚ｔ(mm)とが下記式を満たすことを特徴とする方向性電磁鋼板の製造方法。
記
３≦(Ｘ×ｔ2×1000)/(sol.Al/Ｎ)3≦20 C: 0.04 to 0.12 mass%, Si: 1.5 to 5.0 mass%, Mn: 0.01 to 1.0 mass%, sol.Al: 0.010 to 0.040 mass%, N: 0.004 to 0.02 mass%, S and / or Se: 0.005 to A steel slab containing 0.05 mass% and the balance consisting of Fe and inevitable impurities is heated to 1250 ° C or higher, then hot rolled to a hot rolled sheet with a thickness of 1.8 mm or more, and then subjected to one time or intermediate annealing. A directional electromagnetic consisting of a series of processes in which a cold rolled sheet with a final thickness of 0.14 to 0.20 mm is formed by cold rolling at least twice, and after the primary recrystallization annealing, the annealing separator is applied to the steel sheet and then the finish annealing is performed. In the manufacturing method of the steel sheet,
1 selected from Mg sulfate: Ca sulfate, Ca sulfate, Sr sulfate, Ba sulfate, Mg sulfide, Ca sulfide, Sr sulfide, and Ba sulfide in an annealing separator containing MgO as the main component. 2.0 to 20.0 parts by mass of seeds or two or more kinds are added , the ratio of the sol.Al and N content of the steel slab (sol.Al/N), and Mg sulfate and Ca sulfate added to the annealing separator. The total amount X (parts by mass) of one or more selected from Sr, sulfuric acid Ba, sulfuric acid Mg, Ca sulfide, Ca sulfide, Sr and Ba sulfide and the final thickness t (mm) The manufacturing method of the grain-oriented electrical steel sheet characterized by satisfy | filling .
3 ≦ (X × t 2 × 1000) / (sol.Al/N) 3 ≦ 20
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