JP3033004B2 - Refining method of low Ti content molten steel - Google Patents
Refining method of low Ti content molten steelInfo
- Publication number
- JP3033004B2 JP3033004B2 JP5319684A JP31968493A JP3033004B2 JP 3033004 B2 JP3033004 B2 JP 3033004B2 JP 5319684 A JP5319684 A JP 5319684A JP 31968493 A JP31968493 A JP 31968493A JP 3033004 B2 JP3033004 B2 JP 3033004B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- content
- molten steel
- ferromagnetic iron
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
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- Treatment Of Steel In Its Molten State (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、鋼中Ｔｉ含有量がとり
わけ製品品質、特性に重大な影響を及ぼす鋼種における
鋼中のＴｉ含有量を効果的に低減する取鍋精錬方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladle refining method for effectively reducing the Ti content of steel in a steel grade in which the Ti content in steel has a significant effect on product quality and properties.
【０００２】[0002]
【従来の技術】鋼中Ｔｉ含有量が製品品質、特性に重大
な影響を及ぼす鋼種として、例えば、けい素鋼などがあ
げられる。けい素鋼は鋼中の微量不純物元素であるＴｉ
やＺｒ等を低減することにより、その電磁特性が著しく
向上することが知られている。これは、例えばＴｉを低
減すると、ＴｉＯ2 、ＴｉＮ等の微細介在物や微細析出
物が減少し、鋼板の回復、再結晶の過程で結晶粒界の移
動が容易となり、均一で粗大化された再結晶粒が得やす
くなるためである。2. Description of the Related Art Examples of steel types in which the Ti content in steel has a significant effect on product quality and properties include silicon steel. Silicon steel is Ti, a trace impurity element in steel.
It has been known that the electromagnetic characteristics are significantly improved by reducing Zr or Zr. This is because, for example, when Ti is reduced, fine inclusions and fine precipitates such as TiO 2 and TiN are reduced, and the movement of the crystal grain boundary in the process of recovery and recrystallization of the steel sheet is facilitated, and uniform and coarse. This is because recrystallized grains are easily obtained.
【０００３】従来、鋼中Ｔｉの含有量を低減する方法と
して、（１）溶銑中のＴｉ含有量を低減し、転炉等の製
鋼炉の出鋼Ｔｉ含有量及びスラグ中（ＴｉＯ2 ）含有量
を低減する、（２）転炉等の製鋼炉の出鋼時に流出する
炉内スラグ量をスラグストッパー等を用いて低減し、取
鍋のスラグの塩基度を低めにコントロールしてＴｉを低
減する（特公平３−７９４０７号公報）、（３）転炉等
の製鋼炉からの出鋼時あるいは出鋼後に添加する合金鉄
中のＴｉ含有量を低減して、取鍋内溶鋼中へのＴｉのイ
ンプットを減らす、等の対策がとられていた。Conventionally, methods for reducing the content of Ti in steel include (1) reducing the content of Ti in the hot metal, and the content of Ti in the steelmaking furnace such as a converter and the content of (TiO 2 ) in slag. (2) Reduce the amount of in-furnace slag flowing out of the steelmaking furnace, such as a converter, at tapping using a slag stopper, etc., and control the slag basicity of the ladle to a lower level to reduce Ti. (Japanese Patent Publication No. 3-79407), (3) The Ti content in the ferromagnetic iron added at or after tapping from a steelmaking furnace such as a converter is reduced, and the Ti content in the molten steel in the ladle is reduced. Measures such as reducing the input of Ti were taken.
【０００４】これらの鋼中Ｔｉ含有量低減方策により、
実績のＴｉ含有量はかなり低い値が得られている。[0004] By these measures for reducing the Ti content in steel,
The actual Ti content is quite low.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、前述の
けい素鋼のうち、材料特性上の対策として、鋼中Ｐの含
有量を０．０４％を超えるようにコントロールすること
が必要な鋼種がある。このけい素鋼を、溶銑中のＴｉ含
有量を低減し、転炉等の製鋼炉の出鋼Ｔｉ含有量及びス
ラグ中（ＴｉＯ2 ）含有量を低減する方法により得る場
合には、低Ｔｉ含有の溶銑を得ること自体が溶銑コスト
の負担を大きくし、また特公平３−７９４０７号公報に
示されるように、出鋼時の炉内スラグ量の流出を抑制す
るかあるいはスラグ塩基度を低めにコントロールする方
法により得る場合は、スラグの流出の抑制はかなり変動
して安定的にコントロールできず、しかもスラグ塩基度
を低めにコントロールする場合も塩基度コントロール用
副原料を要し、かつ溶鋼の温度低下等の問題が生じる。
さらに、出鋼後に添加する合金鉄中のＴｉ含有量を低減
するには特定の合金鉄の選択が必要であり、これ等もコ
スト負担を大きくする要因である等多くの問題点を含ん
でいる。However, among the above-mentioned silicon steels, there is a steel type for which it is necessary to control the content of P in the steel so as to exceed 0.04% as a measure against material properties. . When this silicon steel is obtained by a method of reducing the Ti content in hot metal and reducing the tapping Ti content of a steelmaking furnace such as a converter and the (TiO 2 ) content in slag, a low Ti content is obtained. The hot metal itself increases the burden of hot metal cost and, as shown in Japanese Patent Publication No. 3-79407, suppresses the flow of slag in the furnace during tapping or reduces the basicity of slag. When obtained by the control method, the control of slag outflow is considerably fluctuated and cannot be controlled stably, and even when the slag basicity is controlled to a low level, auxiliary raw materials for basicity control are required, and the temperature of the molten steel is reduced. Problems such as lowering occur.
Furthermore, in order to reduce the Ti content in ferromagnetic iron added after tapping, it is necessary to select a specific ferromagnetic iron, which also has many problems such as a factor that increases the cost burden. .
【０００６】特にＰ含有合金鉄中にはＴｉが含有されて
いるものがあり、ＡｌまたはＳｉ含有合金鉄を添加後、
あるいはＡｌやＳｉ含有合金鉄と同時にＰ含有合金鉄を
添加すると鋼中Ｔｉ含有量が増加する。しかも、Ｔｉは
Ｐ含有合金鉄の製造工程で不可避的に入るため、Ｔｉに
関する仕様をＰ含有合金鉄に付加することは極めて難し
く、またこれを敢えて行えば著しいコストアップとな
る。[0006] In particular, some P-containing ferroalloys contain Ti, and after adding Al or Si-containing ferroalloys,
Alternatively, when a P-containing ferromagnetic iron is added simultaneously with an Al or Si-containing ferromagnetic iron, the Ti content in the steel increases. In addition, since Ti is inevitably included in the manufacturing process of P-containing ferromagnetic iron, it is extremely difficult to add Ti-related specifications to P-containing ferromagnetic iron.
【０００７】本発明はこれ等従来の問題点であるＴｉの
含有量の変動を防止して安定的に低減し、しかもコスト
負担のない鋼中のＴｉ含有量を効果的に低減する取鍋精
錬方法を提供することを目的とする。[0007] The present invention provides a ladle refining method for stably reducing the content of Ti, which is a conventional problem, by effectively preventing the change in the content of Ti, and effectively reducing the Ti content in steel without cost burden. The aim is to provide a method.
【０００８】[0008]
【課題を解決するための手段】製鋼炉で溶製された未脱
酸溶鋼、もしくは弱脱酸溶鋼を取鍋精錬処理する場合に
おける、Ａｌ，Ｔｉ，Ｐ，Ｓｉの各元素の脱酸平衡を調
査したところ、脱酸力の強さは、Ａｌが最も強く、Ｔ
ｉ，Ｓｉ，Ｐの順に弱くなっている。また、Ｐ含有合金
鉄を添加する時の溶鋼中の溶解酸素濃度と鋼中Ｔｉ濃度
との関係を調査したところ、溶解酸素濃度が高いほど鋼
中Ｔｉ濃度が低いことが新たに判明した。Means for Solving the Problems The deoxidation equilibrium of each element of Al, Ti, P and Si in the case of ladle refining of undeoxidized molten steel or weakly deoxidized molten steel produced in a steelmaking furnace is investigated. According to the investigation, Al had the strongest deoxidizing power and T
It becomes weaker in the order of i, Si, and P. Further, when the relationship between the dissolved oxygen concentration in the molten steel and the Ti concentration in the steel at the time of adding the P-containing ferromagnetic iron was investigated, it was newly found that the higher the dissolved oxygen concentration, the lower the Ti concentration in the steel.
【０００９】よって従来のように最も脱酸力の強いＡｌ
を添加して、鋼中の溶解酸素濃度を低位に除去した後、
Ｔｉを含むＰ含有合金鉄を添加すると、添加されたＴｉ
は溶鋼中に歩留り良く残留し、けい素鋼板の製品の電磁
特性を悪化する程の鋼中Ｔｉ含有量となることを知見し
た。本発明の要旨とするところは、脱酸の順序を変更し
鋼中の溶解酸素濃度が１００ｐｐｍを超える溶鋼に、Ｔ
ｉを含むＰ含有合金鉄を添加することにより、鋼中Ｐ含
有量を０．０４％を超える所定の値にコントロールしな
がら、かつ鋼中Ｔｉ含有量を低減することを特徴とする
低Ｔｉ含有溶鋼の精錬方法にある。Therefore, Al having the strongest deoxidizing power as in the prior art
To remove the dissolved oxygen concentration in the steel to a low level,
When the P-containing ferromagnetic iron containing Ti is added, the added Ti
Found that Ti remained in the molten steel with a good yield, and the Ti content in the steel was such that the electromagnetic characteristics of the silicon steel product deteriorated. The gist of the present invention is that the order of deoxidation is changed so that molten steel having a dissolved oxygen concentration of more than 100 ppm
A low Ti content, characterized by adding a P-containing ferromagnetic iron containing i to reduce the Ti content in the steel while controlling the P content in the steel to a predetermined value exceeding 0.04%. It is in the method of refining molten steel.
【００１０】図１は溶鋼中におけるＡｌ，Ｔｉ，Ｐ，Ｓ
ｉの脱酸力の比較を示すが、図からわかるように、脱酸
力はＡｌ，Ｔｉ，Ｓｉ，Ｐの順に弱くなる。よって、Ａ
ｌにより脱酸された後、あるいは多量のＳｉにより脱酸
された後は、溶鋼中の溶解酸素濃度が低くなり、Ｔｉを
含むＰ含有合金鉄を添加した場合溶鋼中にＴｉが残留す
る可能性が充分考えられる。FIG. 1 shows Al, Ti, P, S in molten steel.
A comparison of the deoxidizing power of i is shown. As can be seen from the figure, the deoxidizing power decreases in the order of Al, Ti, Si, and P. Therefore, A
After being deoxidized by 1 or by a large amount of Si, the dissolved oxygen concentration in the molten steel becomes low, and when P-containing ferromagnetic iron containing Ti is added, Ti may remain in the molten steel. Is conceivable enough.
【００１１】図２に、Ｐ含有合金鉄を添加する時の溶鋼
中の溶解酸素濃度と鋼中Ｔｉ濃度との関係を示す。この
図からわかるように、溶鋼中の溶解酸素濃度が１００ｐ
ｐｍ超、好ましくは２００ｐｐｍ以上で鋼中Ｔｉ濃度は
低位に安定しているが、Ａｌ，Ｓｉ等による脱酸で溶鋼
中の溶解酸素濃度が低くなると、鋼中Ｔｉ濃度はかなり
高くなる。FIG. 2 shows the relationship between the dissolved oxygen concentration in molten steel and the Ti concentration in steel when P-containing ferromagnetic iron is added. As can be seen from this figure, the dissolved oxygen concentration in the molten steel is 100 p.
Although the Ti concentration in the steel is stable at a level higher than pm, preferably 200 ppm or more, the Ti concentration in the steel becomes considerably high when the dissolved oxygen concentration in the molten steel is reduced by deoxidation with Al, Si or the like.
【００１２】転炉等の製鋼炉で溶製された溶鋼は、通常
０．０１〜０．０２％のＰ含有量となっている。この溶
鋼に対し、Ｐ含有合金鉄を添加して溶鋼中のＰ含有量を
目標の値まで高くするわけであるが、目標Ｐ含有量が高
い程添加するＰ含有合金鉄の使用量が増加し、よってＰ
含有合金鉄中のＴｉによる溶鋼中Ｔｉ濃度が上昇すると
考えられた。Molten steel produced in a steelmaking furnace such as a converter usually has a P content of 0.01 to 0.02%. The P-containing ferromagnetic iron is added to the molten steel to increase the P content in the molten steel to a target value. The higher the target P content, the more the amount of the P-containing ferromagnetic iron to be added increases. , So P
It was considered that the Ti concentration in the molten steel due to the Ti in the contained ferromagnetic iron increased.
【００１３】目標鋼中Ｐ含有量（即ち、Ｐ含有合金鉄の
使用量）と溶鋼中Ｔｉ濃度との関係を調査したところ、
鋼中Ｐ含有量が０．０４％を超える溶鋼でＴｉ濃度が著
しく上昇しているのに対し、鋼中Ｐ含有量が０．０４％
より少ない鋼ではＴｉ濃度の上昇は見られたものの品質
特性に悪影響を及ぼす程の顕著なレベルには達しなかっ
た。これは、上述したようにＰ含有合金鉄添加前の溶鋼
は、通常０．０１〜０．０２％のＰを含有しており、目
標鋼中Ｐ含有量が０．０４％より少ない鋼では、Ｐ含有
合金鉄の添加量が極めて少ないためであることと、少量
添加されたＰ含有合金鉄のＴｉが、残留溶解酸素によっ
て酸化されたり、また取鍋あるいは槽内のスラグによっ
て酸化除去されたためと推定される。When the relationship between the target P content in steel (ie, the amount of P-containing ferroalloy used) and the Ti concentration in molten steel was investigated,
In molten steel having a P content of more than 0.04% in the steel, the Ti concentration is significantly increased, while the P content in the steel is 0.04%.
With lower steels, the increase in Ti concentration was seen but did not reach a significant level that adversely affected the quality characteristics. This is because, as described above, molten steel before the addition of P-containing ferroalloys usually contains 0.01 to 0.02% of P, and in steels having a target steel with a P content of less than 0.04%, The reason is that the addition amount of the P-containing ferromagnetic iron is extremely small, and that the Ti of the P-containing ferromagnetic iron added in a small amount is oxidized by the residual dissolved oxygen or oxidized and removed by the slag in the ladle or the tank. Presumed.
【００１４】従って、溶鋼中の溶解酸素濃度と鋼中のＰ
含有量の両方から最適な鋼中の溶解酸素濃度を考慮し、
Ｐ含有合金鉄を添加することにより低Ｔｉ含有溶鋼の精
錬が効率良く達成される。Therefore, the dissolved oxygen concentration in the molten steel and the P
Considering the optimal dissolved oxygen concentration in the steel from both the content,
Refining of low Ti-containing molten steel is efficiently achieved by adding the P-containing ferromagnetic iron.
【００１５】[0015]
【実施例】真空脱炭後、鋼中酸素濃度が２００〜３００
ｐｐｍと充分高い時期にＰ含有合金鉄を添加し、その後
Ａｌ、その他合金鉄を添加する本発明と、例えばＤＨの
ような脱ガス装置により真空脱炭後Ａｌを添加し、鋼中
酸素濃度が１０ｐｐｍ以下でＰ含有合金鉄及び他の合金
鉄を添加する従来の処理で、鋼中のＰ含有量は０．０５
％の条件で低Ｔｉ含有溶鋼の精錬を行った場合を図３
（本発明法）、図４（従来法）に示す。図３から本発明
の精錬処理パターンによって得られた溶鋼のＴｉ含有量
は０．００１〜０．００３％と極めて低位に安定してい
るのに対して、図４（従来法）では０．００１〜０．０
０５％であり、平均値も本発明の０．００１８％に対
し、０．００４１％と効果上に顕著な差があることが分
かる。[Example] After vacuum decarburization, the oxygen concentration in steel was 200-300.
The present invention in which a P-containing ferromagnetic iron is added at a time sufficiently high as ppm and then Al and other ferromagnetic irons are added, and for example, Al is added after vacuum decarburization by a degassing device such as DH, so that the oxygen concentration in the steel is reduced. With conventional processing of adding P-containing ferromagnetic iron and other ferromagnetic iron at 10 ppm or less, the P content in steel is 0.05
Fig. 3 shows the case of refining molten steel with low Ti content
(Method of the present invention) and FIG. 4 (Conventional method). From FIG. 3, the Ti content of the molten steel obtained by the refining processing pattern of the present invention is extremely low and stable at 0.001 to 0.003%, whereas in FIG. 4 (conventional method), it is 0.001. ~ 0.0
The average value was 0.0041% compared to 0.0018% in the present invention, indicating that there is a remarkable difference in effect.
【００１６】[0016]
【発明の効果】本発明によれば、鋼中Ｔｉ含有量は効果
的に低減され、これにより特に鋼中Ｔｉ含有量によって
その製品特性が大きく影響される鋼種について、大幅な
特性改善が可能となり、また、鋼中Ｔｉ含有量の低減の
ために、溶銑コスト増あるいはスラグコントロール用副
材量コスト増がなく、鋼中Ｔｉ低減の安定化が達成され
る。According to the present invention, the content of Ti in steel is effectively reduced, thereby making it possible to greatly improve the properties of steels whose product properties are greatly affected by the content of Ti in steel. Further, since the Ti content in the steel is reduced, there is no increase in the cost of hot metal or the cost of the auxiliary material for slag control, and the stabilization of the reduction of Ti in the steel is achieved.
【図１】溶鋼中におけるＡｌ，Ｔｉ，Ｐ，Ｓｉの脱酸力
の比較を示す図である。FIG. 1 is a diagram showing a comparison of the deoxidizing power of Al, Ti, P, and Si in molten steel.
【図２】Ｐ含有合金鉄を添加する時の溶鋼中の溶解酸素
濃度と鋼中Ｔｉ濃度との関係を示す図である。FIG. 2 is a graph showing the relationship between the dissolved oxygen concentration in molten steel and the Ti concentration in steel when a P-containing ferromagnetic iron is added.
【図３】本発明の一実施例の鋼中Ｔｉ含有量の分布とそ
の平均値を示す図である。FIG. 3 is a diagram showing a distribution of Ti content in steel and an average value thereof in one example of the present invention.
【図４】従来法の鋼中Ｔｉ含有量の分布とその平均値を
示す図である。FIG. 4 is a diagram showing a distribution of Ti content in steel and an average value thereof in a conventional method.
Claims (1)
弱脱酸溶鋼の取鍋精錬処理において、鋼中Ｐ含有量が
０．０４％を超える溶鋼に精錬するに当たり、Ｐ含有合
金鉄を鋼中の溶解酸素濃度が１００ｐｐｍを超える溶鋼
に添加することを特徴とする低Ｔｉ含有溶鋼の精錬方
法。1. In a ladle refining process of undeoxidized or weakly deoxidized molten steel melted in a steelmaking furnace, in refining molten steel having a P content of more than 0.04% in steel, the ferrous alloy containing P Refining method for molten steel having a low Ti content, characterized by adding to a molten steel having a dissolved oxygen concentration of more than 100 ppm in the steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5319684A JP3033004B2 (en) | 1993-12-20 | 1993-12-20 | Refining method of low Ti content molten steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5319684A JP3033004B2 (en) | 1993-12-20 | 1993-12-20 | Refining method of low Ti content molten steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07173519A JPH07173519A (en) | 1995-07-11 |
| JP3033004B2 true JP3033004B2 (en) | 2000-04-17 |
Family
ID=18113037
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5319684A Expired - Fee Related JP3033004B2 (en) | 1993-12-20 | 1993-12-20 | Refining method of low Ti content molten steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3033004B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102296157B (en) | 2010-06-23 | 2013-03-13 | 宝山钢铁股份有限公司 | Very low Ti control method of ultralow-carbon aluminum-silicon killed steel |
| CN102796948B (en) * | 2011-05-27 | 2014-03-19 | 宝山钢铁股份有限公司 | Non-oriented electrical steel plate with extremely low content of Ti and smelting method for non-oriented electrical steel plate |
-
1993
- 1993-12-20 JP JP5319684A patent/JP3033004B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07173519A (en) | 1995-07-11 |
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