JP3364534B2 - Manufacturing method of high clean steel - Google Patents
Manufacturing method of high clean steelInfo
- Publication number
- JP3364534B2 JP3364534B2 JP18137994A JP18137994A JP3364534B2 JP 3364534 B2 JP3364534 B2 JP 3364534B2 JP 18137994 A JP18137994 A JP 18137994A JP 18137994 A JP18137994 A JP 18137994A JP 3364534 B2 JP3364534 B2 JP 3364534B2
- Authority
- JP
- Japan
- Prior art keywords
- slag
- steel
- added
- molten steel
- ladle
- 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
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、転炉、電気炉などの酸
素を使用する精錬炉から出鋼する際に流出スラグを改質
する高清浄鋼の製造方法に関し、特に、製品欠陥の原因
となるアルミナ介在物などを除去するような取鍋スラグ
組成を形成させ、製品品質の向上を図る高清浄鋼の製造
方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing high-cleanliness steel for reforming outflow slag when tapping steel from a refining furnace using oxygen such as a converter and an electric furnace, and particularly to a cause of product defects. The present invention relates to a method for producing high-cleanliness steel for improving product quality by forming a ladle slag composition that removes alumina inclusions and the like.
【０００２】[0002]
【従来の技術】一般に、転炉等で生成された溶鋼は、成
分調整及び脱酸調整を実施し、溶鋼中の酸素量を制御し
ている。しかし、溶鋼上部に存在する酸化溶融スラグは
完全には脱酸されていないため、脱酸剤添加から溶鋼凝
固までの間に溶鋼中の酸素と親和力の強い元素（たとえ
ばＡｌ等）と、溶鋼上部に存在する酸化溶融スラグ（た
とえば酸化Ｆｅ、Ｍｎ等）とが反応し、脱酸物を生成す
る。この結果、鋼中酸素制御が著しく損なわれると共
に、生成した脱酸物が鋼の製品品質劣化の原因となって
いる。2. Description of the Related Art Generally, molten steel produced in a converter or the like is subjected to component adjustment and deoxidation adjustment to control the amount of oxygen in the molten steel. However, since the oxidized molten slag existing in the upper portion of the molten steel is not completely deoxidized, an element having a strong affinity with oxygen in the molten steel (such as Al) and the upper portion of the molten steel during the period from the addition of the deoxidizer to the solidification of the molten steel. Reacts with the oxidized molten slag (for example, Fe oxide, Mn, etc.) present in to produce a deoxidized product. As a result, the control of oxygen in the steel is significantly impaired, and the deoxidized product produced causes deterioration of the product quality of the steel.
【０００３】そこで従来より、この脱酸物が原因となっ
て生じる鋼の品質低下を防止するための種々の手法が提
案されている。Therefore, conventionally, various techniques have been proposed for preventing the deterioration of steel quality caused by the deoxidized product.
【０００４】特開昭６１−１９７２３号公報には、溶鋼
を溶解炉から取鍋に出鋼する際に、溶鋼中のｓｏｌ．Ａ
ｌを０．５０％以上となるようにＡｌを添加すること
で、鋼中酸素をＡｌ2 Ｏ3 としてスラグ化し、鋼中酸素
２０ｐｐｍ以下の清浄鋼を製造する方法が記載されてい
る。Japanese Patent Laid-Open No. 61-19723 discloses that when molten steel is tapped from a melting furnace to a ladle, sol. A
A method is described in which oxygen in steel is converted to Al 2 O 3 to form slag by adding Al so that 1 is 0.50% or more, and a clean steel having oxygen in steel of 20 ppm or less is produced.
【０００５】また、特開昭６１−２６６１７０号公報に
は、スラグの酸化膜上に珪酸塩質の改質剤を添加し、さ
らにＡｌ、石炭などの発熱剤を添加して昇温効果を高め
て取鍋を振動させて表面硬化スラグも改質剤と溶融反応
させ、改質作業が終了したのちに取鍋内残存物を排出す
るようにした製鋼スラグの改質方法が記載されている。In Japanese Patent Laid-Open No. 61-266170, a silicate modifier is added on the oxide film of slag, and a heat generating agent such as Al or coal is added to enhance the temperature raising effect. There is described a method for reforming steelmaking slag in which the ladle is vibrated to cause the surface-hardened slag to melt and react with the modifier, and after the reforming work is completed, the residue in the ladle is discharged.
【０００６】また、特開昭６３−２６２４１２号公報に
は、精錬直後の溶鋼表面スラグに強脱酸剤を添加してガ
ス攪拌してスラグ中のＦｅＯ、ＭｎＯを還元し、溶鋼ガ
ス攪拌で脱酸生成物を浮上させて除去する溶鋼の清浄化
方法が記載されている。Further, in Japanese Patent Laid-Open No. 63-262412, a strong deoxidizing agent is added to molten steel surface slag immediately after refining and gas stirring is performed to reduce FeO and MnO in the slag, and degassing is performed by stirring molten steel gas. A method for cleaning molten steel is described in which acid products are floated and removed.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、上記特
開昭６１−１９７２３号公報に記載の方法は、出鋼中に
Ａｌを添加し、溶鋼中のｓｏｌ．Ａｌを０．５０％以上
の高Ａｌ溶鋼とする必要があるため、合金コストが高く
なるという問題がある。またこの脱酸処理の後に目標Ａ
ｌ成分に到達するための脱Ａｌ処理が必要となり、操業
工程が複雑化するという問題も生じる。However, in the method described in the above-mentioned Japanese Patent Laid-Open No. 61-19723, Al is added to the tapped steel, and sol. Since Al needs to be a high Al molten steel of 0.50% or more, there is a problem that the alloy cost becomes high. In addition, after this deoxidation treatment, the target A
There is also a problem that a de-Al treatment for reaching the l component is required, which complicates the operation process.
【０００８】また、上記特開昭６１−２６６１７０号公
報に記載の方法は、スラグ酸化膜を含めての改質を目的
としているが、転炉流出スラグは塩基度が高く溶融温度
が高いため、この方法ではスラグ溶融は困難であり、た
とえば、連続鋳造においてノズル閉塞を招き、操業の安
定性に欠けるという問題がある。また、スラグ攪拌に関
しても取鍋振動のみでは充分な攪拌混合は達成されない
という問題がある。Further, the method described in JP-A-61-266170 aims at reforming including a slag oxide film, but since the slag flowing out of the converter has a high basicity and a high melting temperature, With this method, slag melting is difficult, and for example, there is a problem that nozzle clogging occurs in continuous casting, resulting in lack of operational stability. Also, regarding slag stirring, there is a problem that sufficient stirring and mixing cannot be achieved only by ladle vibration.
【０００９】また、特開昭６３−２６２４１２号公報に
記載の方法は、強脱酸剤を添加してスラグの酸化度を低
下させ、二次精錬処理中に溶鋼中のＡｌと酸素が反応し
てＡｌ2 Ｏ3 が生成することを抑制するものであるが、
転炉流出スラグは塩基度が高く難溶融であるためスラグ
との均一反応は困難であり、スラグ固相が大きく生成Ａ
ｌ2 Ｏ3 の吸収能も小さいという問題がある。Further, in the method described in JP-A-63-262412, a strong deoxidizer is added to reduce the oxidation degree of slag, and Al in the molten steel reacts with oxygen during the secondary refining treatment. To suppress the formation of Al 2 O 3 by
Since the slag flowing out of the converter has a high basicity and is difficult to melt, a uniform reaction with the slag is difficult and a large solid phase of slag is generated A
There is a problem that the absorption capacity of l 2 O 3 is also small.
【００１０】そこで本発明は、比較的簡単な工程を使用
し、アルミナ介在物を減らして製品の質を向上させると
共に、スラグを軟質化して鋳造操業の安定化を図ること
を目的とする。Therefore, the object of the present invention is to use a relatively simple process to reduce the inclusions of alumina to improve the quality of the product and to soften the slag to stabilize the casting operation.
【００１１】[0011]
【課題を解決するための手段】従来技術においては、取
鍋スラグ中のＳｉＯ2 ，ＭｎＯなどの低級酸化物が溶鋼
に対する酸素源として働き、Ａｌ2 Ｏ3 などの介在物を
生成するものと考え、酸素ポテンシャルの低下及びスラ
グ固化による反応抑制を実施してきた。In the prior art, it is considered that lower oxides such as SiO 2 and MnO in ladle slag act as an oxygen source for molten steel to form inclusions such as Al 2 O 3. , The oxygen potential has been reduced and the reaction has been suppressed by slag solidification.
【００１２】しかし、詳細調査を実施した結果、製品欠
陥と取鍋内スラグ酸化度低下あるいはＣａＯ添加による
チル化の効果は希薄であり、スラグ組成に大きく影響さ
れていることが判明した。[0012] However, as a result of detailed investigation, it was found that the product defects and the effect of lowering the degree of slag oxidation in the ladle or the chilling effect due to the addition of CaO were scarce and were greatly influenced by the slag composition.
【００１３】本発明においては、出鋼段階においてスラ
グ脱酸用Ａｌと組成制御用ＣａＯに加えて、流出スラグ
と添加ＣａＯの滓化促進を図るために、低融点のカルシ
ウム・アルミネートを添加する。カルシウム・アルミネ
ートは、重量比で投入石灰量の５％以上添加してスラグ
滓化を促進させ、精錬処理中に生成するアルミナ介在物
の吸収能を高める。In the present invention, in addition to Al for slag deoxidation and CaO for composition control in the tapping stage, low melting point calcium aluminate is added in order to promote slag formation of slag outflow and added CaO. . Calcium aluminate is added in an amount of 5% or more of the amount of lime added in a weight ratio to accelerate slag slag formation and enhance the absorption capacity of alumina inclusions generated during the refining process.
【００１４】[0014]
【作用】製品成績とスラグ中のＦｅＯ、ＭｎＯなどの低
級酸化物の含有量との間には、図１のような関係が確認
されている。図においては、製品成績は介在物指数で表
されている。図から判るように、スラグ中のＴ．Ｆｅ＋
ＭｎＯの量が８〜１０重量％より大きくなると、急激に
製品成績が悪化する。これは、精錬処理中に捲込まれた
スラグと鋼中のＡｌ成分との反応、あるいは、合金添加
時における酸化などで生成したＡｌ2 Ｏ3 系介在物に起
因するものである。The relationship between the product performance and the contents of lower oxides such as FeO and MnO in the slag has been confirmed as shown in FIG. In the figure, product performance is represented by inclusion index. As can be seen from the figure, the T. Fe +
When the amount of MnO is more than 8 to 10% by weight, the product performance deteriorates sharply. This is due to the reaction between the slag caught during the refining treatment and the Al component in the steel, or the Al 2 O 3 -based inclusions generated by the oxidation during addition of the alloy.
【００１５】実際、製品介在物としてはＡｌ2 Ｏ3 系介
在物が検出されており、スラグ改質の効率化と完全
シール化による二次酸化の抑制が必要である。In fact, Al 2 O 3 type inclusions have been detected as product inclusions, and it is necessary to suppress secondary oxidation by improving the efficiency of slag reforming and forming a complete seal.
【００１６】図２は、本発明における操業方法を説明す
るための模式図である。本発明においては、転炉１から
取鍋２に対して出鋼する際に、出鋼時の溶鋼熱と出鋼流
による攪拌力を利用して、スラグ滓化を目的として、Ｃ
ａＯと低融点化合物のカルシウム・アルミネート（１２
ＣａＯ ７Ａｌ2 Ｏ3 ）を同時に添加する。そして、出
鋼後にはスラグ低級酸化物を還元するためにＡｌなどの
脱酸材を添加する。FIG. 2 is a schematic diagram for explaining the operating method in the present invention. In the present invention, when steel is tapped from the converter 1 to the ladle 2, the molten steel heat at the tapping and the stirring force due to the tapping flow are used for the purpose of converting slag to C.
aO and low melting point compound calcium aluminate (12
CaO 7 Al 2 O 3 ) is added simultaneously. After tapping, a deoxidizer such as Al is added to reduce the slag lower oxide.
【００１７】本発明においては、カルシウム・アルミネ
ートがスラグ滓化促進剤として働き、高塩基度スラグも
滓化する。また、スラグ流動性が高くなり、転炉スラグ
と造滓剤との均一化及びスラグ脱酸剤との反応が効率化
され、スラグ酸化度を安定的に低位にさせることが可能
である。更に、スラグ溶融化により取鍋内の溶鋼が完全
に被覆され、大気と接触することがないので、二次酸化
が抑制される。In the present invention, calcium aluminate acts as a slag slag formation accelerator, and also slags of high basicity slag. Further, the slag fluidity is increased, the converter slag and the slag forming agent are made uniform, and the reaction with the slag deoxidizer is made efficient, so that the slag oxidation degree can be stably lowered. Further, the molten steel in the ladle is completely covered by the slag melting and does not come into contact with the atmosphere, so secondary oxidation is suppressed.
【００１８】[0018]
【実施例】出鋼中に添加するＣａＯに対するカルシウム
・アルミネートの量を変更して試験を行なった。試験結
果を表１に示す。但し、ＣａＯの添加量は６ｋｇ／ｔと
した。また、製品成績は介在物欠陥の発生率で示した。Example A test was conducted by changing the amount of calcium aluminate with respect to CaO added during tapping. The test results are shown in Table 1. However, the amount of CaO added was 6 kg / t. The product performance is indicated by the incidence of inclusion defects.
【００１９】[0019]
【表１】
カルシウム・アルミネート／ＣａＯを０．０２以上、好
ましくは０．０５以上とすることにより、取鍋スラグの
滓化は良好となり、二次精錬処理後の取鍋スラグの
（Ｔ．Ｆｅ）＋（ＭｎＯ）は安定して５重量％以下まで
低下しており、製品成績も大幅に改善されている。[Table 1] By setting the amount of calcium / aluminate / CaO to 0.02 or more, preferably 0.05 or more, the slag of the ladle slag becomes good, and the (T.Fe) + (of the ladle slag after the secondary refining treatment is obtained. (MnO) is stably reduced to 5 % by weight or less, and the product performance is significantly improved.
【００２０】また、スラグ滓化による溶鋼被覆効果の改
善で、精錬処理での〔Ｎ〕ピックアップは通常操業に比
べ改善される事を確認した。Further, it was confirmed that the improvement of the molten steel coating effect by the slag slag improves the [N] pickup in the refining process as compared with the normal operation.
【００２１】[0021]
【発明の効果】本発明は以下の効果を奏する。The present invention has the following effects.
【００２２】（１）製品におけるアルミナ介在物が低減
し、Ａｌキルドブリキで製品不合発生率が約１／５に低
減した。(1) Alumina inclusions in the product were reduced, and the rate of product incompleteness was reduced to about 1/5 due to Al kill tinplate.
【００２３】（２）取鍋スラグが、低融点で安定なカル
シウム・アルミネート組成に近づくため、連続鋳造にお
けるノズル閉塞が防止され、操業の安定化が図れる。(2) Since the ladle slag comes close to a stable calcium-aluminate composition with a low melting point, nozzle clogging in continuous casting is prevented and the operation can be stabilized.
【図１】 製品成績とスラグ中の低級酸化物の含有量と
の関係を示すグラフである。FIG. 1 is a graph showing the relationship between product performance and the content of lower oxides in slag.
【図２】 本発明における操業方法を説明するための模
式図である。FIG. 2 is a schematic diagram for explaining an operating method according to the present invention.
１…転炉、２…取鍋 1 ... Converter, 2 ... Ladle
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C21C 7/076 C21C 7/00 C21C 7/04 C21C 7/06 ─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) C21C 7/076 C21C 7/00 C21C 7/04 C21C 7/06
Claims (2)
に、ＣａＯとカルシウム・アルミネートを添加して前記
流出スラグと添加ＣａＯの滓化を促進することを特徴と
する高清浄鋼の製造方法。」1. A slag that flows out when tapping from a refining furnace
In the the addition of CaO and calcium aluminate
A method for producing highly clean steel, which comprises promoting slag formation of slag outflow and added CaO . "
する請求項１記載の高清浄鋼の製造方法。2. The method for producing a highly clean steel according to claim 1, wherein a deoxidizing agent is added after tapping.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18137994A JP3364534B2 (en) | 1994-08-02 | 1994-08-02 | Manufacturing method of high clean steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18137994A JP3364534B2 (en) | 1994-08-02 | 1994-08-02 | Manufacturing method of high clean steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0841526A JPH0841526A (en) | 1996-02-13 |
| JP3364534B2 true JP3364534B2 (en) | 2003-01-08 |
Family
ID=16099706
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18137994A Expired - Fee Related JP3364534B2 (en) | 1994-08-02 | 1994-08-02 | Manufacturing method of high clean steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3364534B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104630418B (en) * | 2015-01-15 | 2016-08-24 | 南京钢铁股份有限公司 | A kind of high-cleanness, high pipeline steel smelting technique |
| CN109280732A (en) * | 2018-11-08 | 2019-01-29 | 南京钢铁股份有限公司 | A kind of high cleanliness acid-resistant pipeline steel smelting process |
-
1994
- 1994-08-02 JP JP18137994A patent/JP3364534B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0841526A (en) | 1996-02-13 |
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