JP2002096145A - Continuous casting nozzle and method for continuous casting of steel using it - Google Patents
Continuous casting nozzle and method for continuous casting of steel using itInfo
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- JP2002096145A JP2002096145A JP2000281386A JP2000281386A JP2002096145A JP 2002096145 A JP2002096145 A JP 2002096145A JP 2000281386 A JP2000281386 A JP 2000281386A JP 2000281386 A JP2000281386 A JP 2000281386A JP 2002096145 A JP2002096145 A JP 2002096145A
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- nozzle
- continuous casting
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- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Compositions Of Oxide Ceramics (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、鋼の連続鋳造にお
いて、取鍋からタンディッシュ内、或いはタンディッシ
ュから鋳型内に溶鋼を注入するために使用される連続鋳
造用ノズルおよびそれを用いる連続鋳造方法に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting nozzle used for pouring molten steel from a ladle into a tundish or from a tundish into a mold in continuous casting of steel, and continuous casting using the nozzle. It is about the method.
【０００２】[0002]
【従来の技術】現在、連続鋳造においては、溶鋼を酸化
させることなくタンディッシュから鋳型内に供給するた
めに、連続鋳造用ノズルが利用されている。連続鋳造用
ノズルの材質としては、Ａｌ2 Ｏ3 及びＣを主体とし、
これに２０質量％程度のＳｉＯ 2 を含有するものが主流
となっている。このような、連続鋳造用ノズルでは、鋳
造時間の経過と共に鋼中析出物のＡｌ2 Ｏ3 がノズル内
壁に付着し、激しい場合にはノズル閉塞を引き起こし鋳
造を停止する場合もあった。また、ノズル閉塞は鋳型内
の溶鋼流動を乱す原因にもなるため、パウダー巻き込み
による介在物欠陥を増加させる。2. Description of the Related Art At present, in continuous casting, molten steel is oxidized.
Supply from the tundish to the mold without
For this purpose, a continuous casting nozzle is used. For continuous casting
The material of the nozzle is AlTwoOThreeAnd C as the subject,
About 20% by mass of SiO TwoMainstream containing
It has become. In such a continuous casting nozzle,
The precipitation of Al in steel with the passage ofTwoOThreeIs inside the nozzle
Adhering to the wall, in severe cases, causing nozzle blockage and casting
In some cases, the building was stopped. In addition, nozzle blockage
Powder may cause the flow of molten steel to be disturbed.
Increase inclusion defects.
【０００３】この問題を解決する手段の一つとして、例
えば特公昭５８−３４６７号公報に示されているよう
に、連続鋳造用ノズル内孔と同心円となる多孔質の筒状
耐火物（内孔体）をノズル本体に内挿し、この多孔質耐
火物内壁からＡｒその他の不活性ガスを吹き込むことが
知られている。このガス吹き込みは、ノズル内壁と溶鋼
との接触面積を減少させ、さらに溶鋼を攪拌すること、
或いは付着物をガス気泡により強制的に剥離させること
により、ノズル内壁面へのＡｌ2 Ｏ3 系介在物の付着成
長を防止する効果がある。また、別の手段として、例え
ば特開昭６４−４０１５４号公報に記載されているよう
に、ＺｒＯ2 −ＣａＯ−Ｃ質材料をノズル内壁に用いる
ことで、耐火物中ＣａＯと溶鋼中Ａｌ2 Ｏ3 とを反応さ
せカルシウムアルミネートの低融物を生成させる。この
低融物を溶鋼流により洗い流し、微少な溶損を与えるこ
とにより付着を防止するものである。As one means for solving this problem, as disclosed in Japanese Patent Publication No. 58-3467, for example, a porous cylindrical refractory (inner hole) concentric with the inner hole of a continuous casting nozzle. It has been known that a body is inserted into a nozzle body and Ar or another inert gas is blown from the inner wall of the porous refractory. This gas blowing reduces the contact area between the inner wall of the nozzle and the molten steel, and further stirs the molten steel,
Alternatively, by forcibly peeling off the deposits by gas bubbles, there is an effect of preventing the Al 2 O 3 inclusions from growing on the inner wall surface of the nozzle. As another means, for example, as described in JP-A-64-40154, by using a ZrO 2 —CaO—C material for the inner wall of the nozzle, CaO in the refractory and Al 2 O in the molten steel are used. 3 to form a low melt of calcium aluminate. This low melt is washed away by a molten steel stream to give a small amount of erosion, thereby preventing adhesion.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、ノズル
内壁へのＡｌ2 Ｏ3 の付着を確実に防止するためには、
溶鋼中に多量のＡｒガスを吹き込む必要があり、この場
合吹き込まれたＡｒ気泡は完全に浮上せず、モールド内
で凝固界面に捕捉され、熱間圧延、冷間圧延後に発生す
る気泡系欠陥の原因となる。特に、Ｃ濃度が０．０１％
以下の極低炭素鋼において気泡系欠陥の発生が顕著であ
る。これに対し、連続鋳造用ノズル内壁からのガス吹き
込みを効果的に実施するための各種方法が提案されてい
るが、気泡系欠陥が発生しない程度までＡｒガス流量を
低減し、その上でＡｌ2 Ｏ3 の付着を確実に防止できる
技術は開発されていない。一方、Ａｒガス吹き込みを実
施せず、Ａｌ2 Ｏ3 付着を防止するためにＺｒＯ2 −Ｃ
ａＯ−Ｃ材質のノズルが使用されているが、鋳造時間が
長いか、或いは溶鋼清浄性が低下する場合には、ノズル
内壁に付着したＡｌ2 Ｏ3 を低融点化するのに十分なＣ
ａＯを供給できなくなり、鋳造後半でノズル閉塞が発生
する。このため、ＺｒＯ2 −ＣａＯ−Ｃ質ノズルも確実
な閉塞防止対策になっていないのが現状である。However, in order to reliably prevent Al 2 O 3 from adhering to the inner wall of the nozzle,
It is necessary to blow a large amount of Ar gas into the molten steel. In this case, the blown Ar bubbles do not completely float, are trapped in the solidification interface in the mold, and are caused by bubble-based defects generated after hot rolling and cold rolling. Cause. In particular, the C concentration is 0.01%
In the following ultra-low carbon steels, generation of bubble-type defects is remarkable. On the other hand, various methods for effectively performing gas injection from the inner wall of the continuous casting nozzle have been proposed. However, the Ar gas flow rate is reduced to a level that does not cause bubble-based defects, and the Al 2 flow rate is further reduced. No technique has been developed that can reliably prevent O 3 from adhering. On the other hand, ZrO 2 -C was used to prevent Al 2 O 3 from adhering without blowing Ar gas.
Although a nozzle made of aO-C material is used, when the casting time is long or the cleanliness of molten steel is reduced, sufficient C 2 O 3 to lower the melting point of Al 2 O 3 attached to the inner wall of the nozzle is used.
The aO cannot be supplied, and nozzle clogging occurs in the latter half of casting. For this reason, at present, the ZrO 2 -CaO-C quality nozzle is not a reliable blockage prevention measure.
【０００５】これらの問題点に鑑み、本発明は、気泡系
欠陥を防止できる程度までノズル内壁からのガス吹き込
み流量を低減した上で、溶鋼中介在物のノズル内壁への
付着を確実に防止できる連続鋳造用ノズルとそれを用い
る連続鋳造方法を提供することを目的とするものであ
る。In view of these problems, the present invention can reliably prevent the inclusions in the molten steel from adhering to the inner wall of the nozzle after reducing the flow rate of the gas blown from the inner wall of the nozzle to such an extent that bubble-based defects can be prevented. It is an object of the present invention to provide a continuous casting nozzle and a continuous casting method using the same.
【０００６】[0006]
【課題を解決するための手段】上記課題を解決するため
に、本発明は以下の構成を要旨とする。即ち、 （１）鋼の連続鋳造用ノズルにおいて、ＭｇＯ含有率と
ＭｇＡｌ2 Ｏ4 含有率の総和が５０質量％以上、Ｃ含有
率を５質量％以下とし、工業的に不可避の不純物を含有
した組成の耐火物で構成したことを特徴とする鋼の連続
鋳造用ノズル。 （２）鋼の連続鋳造用ノズルにおいて、溶鋼と接触する
ノズル内壁全体、又はアルミナ付着が進行し易い部分
を、ＭｇＯ含有率とＭｇＡｌ2 Ｏ4 含有率の総和が５０
質量％以上、Ｃ含有率を５質量％以下とし、工業的に不
可避の不純物を含有した組成の耐火物で構成したことを
特徴とする連続鋳造用ノズル。 （３）鋼の連続鋳造用ノズルにおいて、ＭｇＯ含有率と
ＭｇＡｌ2 Ｏ4 含有率の総和が５０質量％以上、Ｃ含有
率を５質量％以下、ＳｉＯ2 含有率を１０質量％以下、
且つＡｌ2 Ｏ4 含有率を１０質量％以下とし、工業的に
不可避の不純物を含有した組成の耐火物で構成したこと
を特徴とする連続鋳造用ノズル。 （４）鋼の連続鋳造用ノズルにおいて、溶鋼と接触する
ノズル内壁全体、又はアルミナ付着が進行し易い部分
を、ＭｇＯ含有率とＭｇＡｌ2 Ｏ4 含有率の総和が５０
質量％以上、Ｃ含有率を５質量％以下、ＳｉＯ2 含有率
を１０質量％以下、且つＡｌ2 Ｏ4 含有率を１０質量％
以下とし、工業的に不可避の不純物を含有した組成の耐
火物で構成したことを特徴とする連続鋳造用ノズル。 （５）炭素濃度を０．０１質量％以下まで脱炭した溶鋼
を連続鋳造するに際し、上記（１）〜（４）のいずれか
１項記載の連続鋳造用ノズルを用いることを特徴とする
鋼の連続鋳造方法。である。Means for Solving the Problems In order to solve the above problems, the present invention has the following features. (1) In a nozzle for continuous casting of steel, the total of the MgO content and the MgAl 2 O 4 content was 50% by mass or more and the C content was 5% by mass or less, and contained impurities that were unavoidable industrially. A nozzle for continuous casting of steel, comprising a refractory having a composition. (2) In the nozzle for continuous casting of steel, the total of the MgO content and the MgAl 2 O 4 content of the entire inner wall of the nozzle in contact with the molten steel or the portion where the alumina adhesion is likely to progress is 50%.
A continuous casting nozzle comprising a mass of not less than 5 mass%, a C content of not more than 5 mass%, and a refractory having a composition containing industrially unavoidable impurities. (3) In the nozzle for continuous casting of steel, the total of the MgO content and the MgAl 2 O 4 content is 50% by mass or more, the C content is 5% by mass or less, the SiO 2 content is 10% by mass or less,
A continuous casting nozzle characterized in that it has an Al 2 O 4 content of 10% by mass or less and is made of a refractory having a composition containing industrially unavoidable impurities. (4) In the nozzle for continuous casting of steel, the total of the MgO content and the MgAl 2 O 4 content of the entire inner wall of the nozzle in contact with the molten steel, or the portion where the alumina adhesion is likely to progress, is 50%.
% By mass, C content of 5% by mass or less, SiO 2 content of 10% by mass or less, and Al 2 O 4 content of 10% by mass.
A continuous casting nozzle comprising: a refractory having a composition containing impurities unavoidable industrially; (5) A steel characterized by using the continuous casting nozzle according to any one of the above (1) to (4) when continuously casting molten steel decarbonized to a carbon concentration of 0.01% by mass or less. Continuous casting method. It is.
【０００７】[0007]
【発明の実施の形態】連続鋳造用ノズルの付着防止技術
を確立するためには、まずノズル内壁へのＡｌ2 Ｏ3 付
着機構を明らかにする必要がある。本発明者らは、実機
鋳造後の連続鋳造用ノズルを詳細に調査した結果、連続
鋳造用ノズルと溶鋼との反応により生成した反応Ａｌ2
Ｏ3 層を起点として、溶鋼中Ａｌ2 Ｏ3 の付着堆積が進
行することを知見した。さらに、連続鋳造用ノズルと溶
鋼との反応機構についても基礎的な検討を行い、付着の
起点となる反応Ａｌ2 Ｏ3 層は以下に示す反応過程を経
て形成されることも明らかにした。まず、（１）式で示
される連続鋳造用ノズル中のＳｉＯ2 がＣにより還元さ
れ、ＳｉＯガス、ＣＯガスを生成する。 ＳｉＯ2 （固）＋Ｃ（固体）＝ＳｉＯ（ガス）＋ＣＯ（ガス） （１） これらガスはノズル耐火物内部を拡散し、ノズル／溶鋼
界面で（２）式、（３）式により溶鋼中のＡｌと反応す
る。 ３ＳｉＯ（ガス）＋２Ａｌ（溶鋼中）＝ Ａｌ2 Ｏ3 （反応アルミナ層）＋３Ｓｉ（溶鋼中） （２） ３ＣＯ（ガス）＋２Ａｌ（溶鋼中）＝ Ａｌ2 Ｏ3 （反応アルミナ層）＋３Ｃ（溶鋼中） （３） この時、ノズル／溶鋼界面に形成される酸化膜が反応し
たＡｌ2 Ｏ3 層である。この反応Ａｌ2 Ｏ3 層は溶鋼中
Ａｌ2 Ｏ3 と付着し易いため、Ａｌ2 Ｏ3 付着の起点と
なる。これらの結果から、連続鋳造用ノズルへのＡｌ2
Ｏ3 付着を防止するためには、まず反応Ａｌ2 Ｏ3 層を
生成させないように（１）式の反応を回避することが重
要であり、その方法としては連続鋳造用ノズル中のＣを
低減することが有効である。DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to establish a technique for preventing adhesion of a continuous casting nozzle, it is first necessary to clarify the mechanism of Al 2 O 3 adhesion on the inner wall of the nozzle. The present inventors have conducted a detailed investigation on the continuous casting nozzle after the actual casting, and found that the reaction Al 2 formed by the reaction between the continuous casting nozzle and the molten steel.
It has been found that the deposition of Al 2 O 3 in molten steel proceeds from the O 3 layer as a starting point. Furthermore, a basic study was also conducted on the reaction mechanism between the continuous casting nozzle and the molten steel, and it was clarified that the reaction Al 2 O 3 layer serving as a starting point of the adhesion was formed through the following reaction process. First, SiO 2 in the continuous casting nozzle represented by the formula (1) is reduced by C to generate SiO gas and CO gas. SiO 2 (solid) + C (solid) = SiO (gas) + CO (gas) (1) These gases diffuse inside the nozzle refractory and are present in the molten steel at the nozzle / molten steel interface according to equations (2) and (3). Reacts with Al. 3SiO (gas) + 2Al (molten steel) = Al 2 O 3 (Reaction alumina layer) + 3Si (molten steel) (2) 3CO (gas) + 2Al (molten steel) = Al 2 O 3 (Reaction alumina layer) + 3C (in the molten steel (3) At this time, the oxide film formed at the nozzle / molten steel interface is the reacted Al 2 O 3 layer. The reaction Al 2 O 3 layer easily adheres to Al 2 O 3 in the molten steel, and thus serves as a starting point for Al 2 O 3 adhesion. From these results, it was found that Al 2
In order to prevent O 3 adhesion, it is important to first avoid the reaction of the formula (1) so as not to form a reactive Al 2 O 3 layer. As a method, C in the continuous casting nozzle is reduced. It is effective to do.
【０００８】上記方法による低Ｃ含有率の、或いはＣを
含有しない連続鋳造用ノズルを使用すると、Ａｌ2 Ｏ3
付着を若干抑制する傾向は見られるが、まだ十分なＡｌ
2 Ｏ 3 付着防止効果は得られない。これは、連続鋳造用
ノズルの構成材質としてＡｌ 2 Ｏ3 が使用されており、
このＡｌ2 Ｏ3 が溶鋼中Ａｌ2 Ｏ3 の付着起点として作
用するためである。本発明者らは、種々の酸化物とＡｌ
2 Ｏ3 との付着し易さは、酸化物と溶鋼間の界面エネル
ギーに依存すること、すなわち酸化物と溶鋼間の界面エ
ネルギーが小さいもの程、溶鋼中のＡｌ2 Ｏ3 と付着し
難い傾向があることを見いだした。この知見に基づけ
ば、ノズル材質としてＡｌ2 Ｏ3 の代わりに、溶鋼との
界面エネルギーを低下させるＭｇＯとＭｇＡｌ2 Ｏ4 を
用いることが、Ａｌ2 Ｏ3 付着の防止に効果的である。
したがって、連続鋳造用ノズルへのＡｌ2 Ｏ3 付着を防
止するためには、Ｃ含有率およびＡｌ2 Ｏ3 含有率を低
減し、その上でＭｇＯ、又ＭｇＡｌ2 Ｏ4 を含有させた
ノズル材質を用いることが有効である。[0008] The low C content or C by the above method
When using a continuous casting nozzle that does not containTwoOThree
There is a tendency to slightly suppress the adhesion, but still sufficient Al
TwoO ThreeNo anti-adhesion effect is obtained. This is for continuous casting
Al as the material of the nozzle TwoOThreeAre used,
This AlTwoOThreeIs Al in molten steelTwoOThreeAs a starting point for
To use. The present inventors have proposed various oxides and Al
TwoOThreeAdhesion between the oxide and the molten steel
Energy, that is, the interface energy between oxide and molten steel.
The smaller the energy, the more Al in the molten steelTwoOThreeAnd adhere
I found that they tend to be difficult. Based on this knowledge
If the nozzle material is AlTwoOThreeInstead of molten steel
MgO and MgAl that lower interfacial energyTwoOFourTo
It is possible to use AlTwoOThreeIt is effective in preventing adhesion.
Therefore, Al to the continuous casting nozzleTwoOThreePrevent adhesion
To stop, C content and AlTwoOThreeLow content
And then MgO and MgAlTwoOFourContained
It is effective to use a nozzle material.
【０００９】実験的検討から、（１）式の反応を溶鋼温
度で防止するためには、連続鋳造用ノズル中のＣ含有率
を５質量％以下にする必要がある。連続鋳造用ノズル中
には、Ａｌ2 Ｏ3 を含有しないことが望ましいが、必要
な場合には１０質量％以下で使用しても良い。Ａｌ2 Ｏ
3 の含有率が１０質量％を超えると、ノズル表面にＡｌ
2 Ｏ3 が露出する確率が高くなり、溶鋼中Ａｌ2 Ｏ3 の
付着起点となるためである。また、連続鋳造用ノズルに
おけるＭｇＯ含有率とＭｇＡｌ2 Ｏ4 含有率の総和を５
０質量％以上確保する必要があり、５０質量％未満では
Ａｌ2 Ｏ3 付着の防止効果が得られないためである。勿
論、ノズル材質としてＭｇＯとＭｇＡｌ 2 Ｏ4 を必ずし
も併用する必要はなく、単独で使用しても各々の含有率
が５０質量％以上であれば良い。低膨張性のＳｉＯ2 は
連続鋳造用ノズルの耐スポーリング性を向上させるた
め、必要な場合には１０質量％以下に限って使用でき
る。これは、ノズル中のＳｉＯ2 含有率が１０質量％を
超えると、溶鋼中のＡｌと直接反応して反応Ａｌ2 Ｏ3
層を生成するためである。From an experimental study, the reaction of equation (1)
In order to prevent the C content in the continuous casting nozzle
Must be 5% by mass or less. Inside the nozzle for continuous casting
Has AlTwoOThreeShould not be contained, but necessary
In such a case, it may be used at 10% by mass or less. AlTwoO
ThreeIf the content exceeds 10% by mass, Al
TwoOThreeIs more likely to be exposed, and AlTwoOThreeof
This is because it becomes an adhesion starting point. In addition, continuous casting nozzles
MgO content and MgAlTwoOFourThe sum of the content rates is 5
It is necessary to secure 0% by mass or more, and if it is less than 50% by mass,
AlTwoOThreeThis is because the effect of preventing adhesion cannot be obtained. Of course
Of the nozzle materials, MgO and MgAl TwoOFourMake sure
It is not necessary to use them together.
Should be 50% by mass or more. Low expansion SiOTwoIs
To improve spalling resistance of continuous casting nozzle
Therefore, if necessary, it can be used only up to 10% by mass.
You. This is due to the SiO in the nozzle.TwoContent is 10% by mass
If it exceeds, it reacts directly with Al in molten steel and reacts with AlTwoOThree
This is for generating a layer.
【００１０】上記ノズル材質は必ずしも連続鋳造用ノズ
ル全体に適用する必要はなく、溶鋼中Ａｌ2 Ｏ3 の付着
するノズル内壁面全体、或いは部分的に適用しても十分
な効果が得られる。本発明のノズル材質は、タンディッ
シュ−鋳型間の浸漬ノズルは勿論であるが、例えば取鍋
−タンディッシュ間の取鍋ノズルでも十分なＡｌ2 Ｏ 3
付着防止効果が得られるため、ここでの連続鋳造用ノズ
ルとは鋳造工程で使用される全てのノズルを指す。[0010] The material of the nozzle is not necessarily a nozzle for continuous casting.
It is not necessary to apply to the entire steelTwoOThreeAdhesion of
Sufficient even if applied to the entire or inner surface of the nozzle
Effects can be obtained. The nozzle material of the present invention is
The immersion nozzle between the shroud and the mold is of course
-Al enough for ladle nozzle between tundishTwoO Three
Since the anti-adhesion effect can be obtained, the nozzle for continuous casting here
The term refers to all nozzles used in the casting process.
【００１１】連続鋳造用ノズルへのＡｌ2 Ｏ3 付着は、
Ｃ濃度が０．０１質量％以下の極低炭素鋼において、特
に顕著である。これは、転炉、真空脱ガス処理により多
量の酸素を用いてＣ濃度を低下させた結果、溶鋼中酸素
濃度が高くなり、脱酸後に多量のＡｌ2 Ｏ3 系介在物を
生成するためである。通常、このような極低炭素鋼はＡ
ｌ2 Ｏ3 −Ｃ−ＳｉＯ2 材質の連続鋳造用ノズルを用い
て、ノズル内にＡｒガスを多量に吹き込むことによりＡ
ｌ2 Ｏ3 付着を回避してきた。しかし、先に述べたよう
に極低炭素鋼はＡｒガスに起因する気泡系欠陥が発生し
易いため、鋳片品質は大きく低下していた。本発明の連
続鋳造用ノズルはＡｌ2 Ｏ3 付着防止効果が非常に高
く、Ａｒガス吹き込み量を大幅に低減できるため、Ａｌ
2 Ｏ3 付着と気泡系欠陥が発生し易い極低炭素鋼の鋳造
に最適である。The adhesion of Al 2 O 3 to the nozzle for continuous casting is as follows.
This is particularly noticeable in ultra-low carbon steel having a C concentration of 0.01% by mass or less. This is because a large amount of oxygen is used in the converter and vacuum degassing to reduce the C concentration, and as a result, the oxygen concentration in the molten steel increases, and a large amount of Al 2 O 3 inclusions are formed after deoxidation. is there. Usually, such ultra-low carbon steel is A
Using a continuous casting nozzle made of l 2 O 3 —C—SiO 2 material, a large amount of Ar gas is blown into the nozzle to obtain A.
l 2 O 3 adhesion has been avoided. However, as described above, ultra-low carbon steel is liable to generate a bubble-type defect caused by Ar gas, so that the slab quality has been greatly reduced. The continuous casting nozzle of the present invention has a very high effect of preventing Al 2 O 3 adhesion and can significantly reduce the amount of Ar gas blown.
It is most suitable for casting ultra-low carbon steel in which 2 O 3 adhesion and bubble defects are likely to occur.
【００１２】[0012]
【実施例】以下に、実施例及び比較例を挙げて、本発明
について説明する。表１に示した原料含有物に結合剤を
外掛けで１０質量％添加して混練し、アイソスタティッ
クプレスを用いて１．０t/cm2 の圧力で図１に示すノズ
ル形状に成形した。１はノズル内壁、２はパウダーライ
ン部、３は吐出孔、４はノズル本体である。なお、パウ
ダーライン部２の耐火物はＺｒＯ2 を７５質量％、Ｃを
２５質量％含有するＺｒＯ2 −Ｃ質に、ノズル本体４の
耐火物はＡｌ2 Ｏ3 を６０質量％、ＳｉＯ2 を１６質量
％、Ｃを２４質量％含有するＡｌ2 Ｏ3 −Ｃ−ＳｉＯ 2
材質に統一した。さらに、この成形体を１２００℃の温
度で還元焼成し、連続鋳造用ノズル（外径１３５mm、内
径９０mm、吐出孔径７０mm、吐出孔角度３５度の逆Ｙ型
ノズル）を作成した。The present invention will be described below with reference to Examples and Comparative Examples.
Will be described. A binder is added to the raw material contents shown in Table 1.
Add 10% by mass on the outside and knead.
1.0t / cm using cuplessTwoAt the pressure of Fig. 1
It was formed into a round shape. 1 is the inner wall of the nozzle, 2 is the powder rye
Portion 3 is a discharge hole, and 4 is a nozzle body. In addition, Pow
The refractory of Darline 2 is ZrOTwo75% by mass, C
ZrO containing 25% by massTwo-C quality, the nozzle body 4
Refractory is AlTwoOThree60% by mass, SiOTwo16 mass
%, Al containing 24% by mass of CTwoOThree-C-SiO Two
Unified to the material. Further, the molded body was heated to 1200 ° C.
And firing for continuous casting, continuous casting nozzle (outside diameter 135mm, inside
Inverted Y type with a diameter of 90 mm, discharge hole diameter of 70 mm, and discharge hole angle of 35 degrees
Nozzle).
【００１３】このようにして得られた連続鋳造用ノズル
を用いて、Ｔｉを０．０２質量％含有する炭素濃度０．
００３質量％の極低炭素鋼を４００分間鋳造した。連続
鋳造用ノズルへのＡｒガス吹き込み量は、本発明の実施
例では２Nl/min、比較例では１０Nl/minとした。本発明
の実施例及び比較例とも鋳造寸法は厚み２４５mm×幅１
５００mmで、８５００mm長さに切断して１コイル単位と
した。このスラブを常法により熱間圧延、冷間圧延し、
最終的に厚み０．７mm×幅１５００mmコイルの冷延鋼板
とした。連続鋳造用ノズルへのＡｌ2 Ｏ3 付着防止効果
については、鋳造後にノズルを回収し、吐出孔直上部の
最大付着厚みを測定し、これを鋳造時間で除すことによ
り付着速度を算出した。また、鋳片品質については、冷
間圧延後の検査ラインで目視観察を行い、１コイル当た
りに発生する気泡系欠陥の個数を評価した。Using the continuous casting nozzle thus obtained, a carbon concentration of 0.02% by mass of Ti and a carbon concentration of 0.02% by mass.
003 mass% ultra low carbon steel was cast for 400 minutes. The amount of Ar gas blown into the continuous casting nozzle was 2 Nl / min in Examples of the present invention and 10 Nl / min in Comparative Examples. The casting dimensions of both the embodiment and the comparative example of the present invention are 245 mm thick × 1 width.
At 500 mm, it was cut into 8500 mm lengths to make one coil unit. This slab is hot-rolled and cold-rolled by a usual method,
Finally, a cold-rolled steel sheet having a thickness of 0.7 mm and a width of 1500 mm was formed. Regarding the effect of preventing Al 2 O 3 from adhering to the continuous casting nozzle, the nozzle was recovered after casting, the maximum adhesion thickness immediately above the discharge hole was measured, and this was divided by the casting time to calculate the adhesion speed. Further, regarding the slab quality, visual observation was performed on an inspection line after cold rolling, and the number of bubble-based defects generated per coil was evaluated.
【００１４】表１に示す如く、実施例では連続鋳造用ノ
ズル内壁全体を、ＭｇＯ含有率とＭｇＡｌ2 Ｏ4 含有率
の和を５０質量％以上、Ｃ含有率を５質量％以下、Ｓｉ
Ｏ2含有率を１０質量％以下、且つＡｌ2 Ｏ4 含有率を
１０質量％以下とした本発明の組成の耐火物で構成した
ことにより、常に安定してＡｌ2 Ｏ3 付着を防止でき
た。また、実施例ではＡｌ2 Ｏ3 付着が殆ど発生せず、
常にＡｒガス吹き込み量を２Nl/minの低位に保持できた
ため、気泡系欠陥の発生もなく、極めて良好な鋳片を得
ることができた。As shown in Table 1, in the embodiment, the entire inner wall of the continuous casting nozzle was made such that the sum of the MgO content and the MgAl 2 O 4 content was 50% by mass or more, the C content was 5% by mass or less, and the Si content was 5% by mass or less.
By using the refractory having the composition of the present invention in which the O 2 content was 10% by mass or less and the Al 2 O 4 content was 10% by mass or less, the adhesion of Al 2 O 3 could be always stably prevented. . In the examples, Al 2 O 3 adhesion hardly occurred,
Since the Ar gas blowing rate could always be maintained at a low level of 2 Nl / min, extremely good cast slabs could be obtained without generation of bubble-based defects.
【００１５】これに対し、比較例１はノズル内壁のＣ含
有率が５％を超えたため、比較例２及び比較例３はＭｇ
Ｏ含有率とＭｇＡｌ2 Ｏ4 含有率の和が５０％未満であ
ったため、何れもＡｌ2 Ｏ3 付着防止効果が十分に得ら
れず、鋳造開始後３００分で鋳造を停止した。また、比
較例ではＡｌ2 Ｏ3 付着が進行したため、Ａｒガスの吹
き込み量を鋳造２００min 以降、１０Nl/minから１５Nl
/minに増加させたため、気泡系欠陥が多発した。On the other hand, in Comparative Example 1, since the C content of the nozzle inner wall exceeded 5%, Comparative Examples 2 and 3
Since the sum of the O content and the MgAl 2 O 4 content was less than 50%, the effect of preventing Al 2 O 3 adhesion was not sufficiently obtained, and the casting was stopped 300 minutes after the start of casting. In the comparative example, since the deposition of Al 2 O 3 progressed, the injection amount of Ar gas was increased from 10 Nl / min to 15 Nl after 200 min of casting.
Since the rate was increased to / min, many bubble-based defects occurred.
【００１６】[0016]
【表１】 [Table 1]
【００１７】[0017]
【発明の効果】以上に説明したように、本発明の連続鋳
造用ノズルによれば、ノズルへのＡｌ 2 Ｏ3 付着を確実
に防止でき、気泡系欠陥も発生しないため、鋳片の品質
向上と安定化を実現でき、歩留まりも格段に向上する。
また、ノズルへのＡｌ2 Ｏ3 付着に起因する種々の非定
常作業を省略することができるため、操業性も良好とな
る。As described above, the continuous casting of the present invention
According to the manufacturing nozzle, the Al TwoOThreeEnsure adhesion
Quality of cast slabs since no air bubbles are generated.
Improvement and stabilization can be realized, and the yield is significantly improved.
In addition, AlTwoOThreeVarious uncertainties due to adhesion
Regular work can be omitted, so operability is also good.
You.
【図１】本発明の連続鋳造用ノズル各部の材質を説明す
るための図である。FIG. 1 is a view for explaining the material of each part of a continuous casting nozzle according to the present invention.
１ ノズル内壁 ２ パウダーライン部 ３ 吐出孔 ４ ノズル本体 DESCRIPTION OF SYMBOLS 1 Nozzle inner wall 2 Powder line part 3 Discharge hole 4 Nozzle body
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｃ０４Ｂ 35/043 Ｃ０４Ｂ 35/04 Ｅ ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) C04B 35/043 C04B 35/04 E
Claims (5)
含有率とＭｇＡｌ2Ｏ4 含有率の総和が５０質量％以
上、Ｃ含有率を５質量％以下とし、工業的に不可避の不
純物を含有した組成の耐火物で構成したことを特徴とす
る鋼の連続鋳造用ノズル。1. A nozzle for continuous casting of steel, comprising:
The steel is characterized in that the sum of the content and the MgAl 2 O 4 content is 50% by mass or more, the C content is 5% by mass or less, and the refractory has a composition containing industrially unavoidable impurities. Nozzle for continuous casting.
接触するノズル内壁全体、又はアルミナ付着が進行し易
い部分を、ＭｇＯ含有率とＭｇＡｌ2 Ｏ4 含有率の総和
が５０質量％以上、Ｃ含有率を５質量％以下とし、工業
的に不可避の不純物を含有した組成の耐火物で構成した
ことを特徴とする連続鋳造用ノズル。2. In a continuous casting nozzle for steel, the entire inner wall of the nozzle in contact with molten steel or a portion where alumina adheres easily progresses, when the sum of the MgO content and the MgAl 2 O 4 content is 50% by mass or more, A continuous casting nozzle having a content of 5% by mass or less and made of a refractory having a composition containing industrially unavoidable impurities.
含有率とＭｇＡｌ2Ｏ4 含有率の総和が５０質量％以
上、Ｃ含有率を５質量％以下、ＳｉＯ2 含有率を１０質
量％以下、且つＡｌ2 Ｏ4 含有率を１０質量％以下と
し、工業的に不可避の不純物を含有した組成の耐火物で
構成したことを特徴とする連続鋳造用ノズル。3. A nozzle for continuous casting of steel, comprising:
The sum of the content and the MgAl 2 O 4 content is 50% by mass or more, the C content is 5% by mass or less, the SiO 2 content is 10% by mass or less, and the Al 2 O 4 content is 10% by mass or less. A nozzle for continuous casting, comprising a refractory having a composition containing impurities that are unavoidable industrially.
接触するノズル内壁全体、又はアルミナ付着が進行し易
い部分を、ＭｇＯ含有率とＭｇＡｌ2 Ｏ4 含有率の総和
が５０質量％以上、Ｃ含有率を５質量％以下、ＳｉＯ2
含有率を１０質量％以下、且つＡｌ2 Ｏ4 含有率を１０
質量％以下とし、工業的に不可避の不純物を含有した組
成の耐火物で構成したことを特徴とする連続鋳造用ノズ
ル。4. In a continuous casting nozzle for steel, the entire inner wall of the nozzle in contact with molten steel or a portion where alumina adheres easily progresses, the total of the MgO content and the MgAl 2 O 4 content is 50% by mass or more, Content of 5% by mass or less, SiO 2
The content is 10% by mass or less, and the Al 2 O 4 content is 10% by mass.
A continuous casting nozzle comprising a refractory having a composition of not more than mass% and containing impurities which are unavoidable industrially.
した溶鋼を連続鋳造するに際し、請求項１〜４のいずれ
か１項記載の連続鋳造用ノズルを用いることを特徴とす
る鋼の連続鋳造方法。5. The continuous casting nozzle according to claim 1, wherein the molten steel decarbonized to a carbon concentration of 0.01% by mass or less is continuously cast. Continuous casting method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000281386A JP2002096145A (en) | 2000-09-18 | 2000-09-18 | Continuous casting nozzle and method for continuous casting of steel using it |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000281386A JP2002096145A (en) | 2000-09-18 | 2000-09-18 | Continuous casting nozzle and method for continuous casting of steel using it |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002096145A true JP2002096145A (en) | 2002-04-02 |
Family
ID=18766050
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000281386A Withdrawn JP2002096145A (en) | 2000-09-18 | 2000-09-18 | Continuous casting nozzle and method for continuous casting of steel using it |
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| Country | Link |
|---|---|
| JP (1) | JP2002096145A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011010501A1 (en) | 2009-07-24 | 2011-01-27 | 黒崎播磨株式会社 | Nozzle for discharging molten metal |
| TWI615220B (en) * | 2016-01-25 | 2018-02-21 | Krosakiharima Corp | Nozzle structure |
-
2000
- 2000-09-18 JP JP2000281386A patent/JP2002096145A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011010501A1 (en) | 2009-07-24 | 2011-01-27 | 黒崎播磨株式会社 | Nozzle for discharging molten metal |
| US8469243B2 (en) | 2009-07-24 | 2013-06-25 | Krosakiharima Corporation | Molten metal discharge nozzle |
| TWI615220B (en) * | 2016-01-25 | 2018-02-21 | Krosakiharima Corp | Nozzle structure |
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