JP2002263808A - Method for cleaning molten steel in tundish - Google Patents
Method for cleaning molten steel in tundishInfo
- Publication number
- JP2002263808A JP2002263808A JP2001072429A JP2001072429A JP2002263808A JP 2002263808 A JP2002263808 A JP 2002263808A JP 2001072429 A JP2001072429 A JP 2001072429A JP 2001072429 A JP2001072429 A JP 2001072429A JP 2002263808 A JP2002263808 A JP 2002263808A
- Authority
- JP
- Japan
- Prior art keywords
- tundish
- molten steel
- steel
- alloy
- gas
- 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.)
- Withdrawn
Links
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に溶鋼を注入する際、急
激な溶鋼の空気酸化を防止し、タンディッシュ内溶鋼の
清浄化を図る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 method for purifying molten steel in a tundish by preventing rapid oxidation of the molten steel in the air when the molten steel is poured into the tundish from a ladle in continuous casting of steel. Things.
【０００２】[0002]
【従来の技術】鋼の連続鋳造において、タンディッシュ
は取鍋と鋳型間に位置し、操業、品質上最も重要な役割
を果たす部分の一つである。その機能は、鋳型内への溶
鋼供給量の調整、溶鋼貯蔵、介在物の分離等である。特
に、介在物除去の機能は、近年の鋼材品質厳格化に伴い
極めて重要な機能となっている。しかし、取鍋からタン
ディッシュ内に溶鋼を注入する際、空気酸化による溶鋼
汚染の問題が生じるため、タンディッシュにおける介在
物除去効果が十分に発揮されていないのが現状である。
このため、タンディッシュ内における溶鋼汚染防止を目
的として、例えば特開昭６１−１７３４５号公報に記載
されているように、注入初期に保温材ボードで蓋をした
タンディッシュ内に不活性ガスを吹き込むことにより、
注入溶鋼の空気酸化防止が図られている。2. Description of the Related Art In continuous casting of steel, a tundish is located between a ladle and a mold and is one of the most important parts in operation and quality. Its functions are adjustment of molten steel supply into the mold, storage of molten steel, separation of inclusions, and the like. In particular, the function of removing inclusions has become an extremely important function with the recent strictness of steel material quality. However, when pouring molten steel from the ladle into the tundish, there is a problem of molten steel contamination due to air oxidation, and at present, the effect of removing inclusions in the tundish is not sufficiently exhibited.
For this reason, for the purpose of preventing molten steel contamination in the tundish, an inert gas is blown into the tundish covered with a heat insulating board at the initial stage of the injection as described in, for example, JP-A-61-17345. By doing
The air oxidation of the injected molten steel is prevented.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、タンデ
ィッシュ内に溶鋼を注入するためには、タンディッシュ
蓋に溶鋼注入用ノズルを挿入できる空間が必要であり、
タンディッシュを完全に密閉することは不可能である。
また、タンディッシュ内に不活性ガスを吹き込む場合、
溶鋼注入用ノズルの周囲にある空間から不活性ガスを吹
き込んでいるが、この方法ではかえって注入点で空気を
巻き込み溶鋼の酸化が激しくなるといった問題も生じ
る。このため、従来のシール方法では空気酸化を防止で
きる程度までタンディッシュ内の酸素濃度を低減できて
いないのが現状である。However, in order to inject molten steel into the tundish, a space for inserting a molten steel injection nozzle into the tundish lid is required.
It is not possible to completely seal the tundish.
Also, when blowing inert gas into the tundish,
Inert gas is blown from the space around the molten steel injection nozzle. However, this method has a problem that air is entrapped at the injection point and oxidation of the molten steel becomes severe. For this reason, at present, the oxygen concentration in the tundish cannot be reduced to the extent that air oxidation can be prevented by the conventional sealing method.
【０００４】これらの問題を鑑み、本発明は、溶鋼の清
浄性を低下させる主原因となっているタンディッシュ内
溶鋼の空気酸化を防止するために、タンディッシュ内の
酸素濃度を迅速で、且つ効率的に低減できる方法を提示
することを目的とするものである。[0004] In view of these problems, the present invention is to quickly and easily reduce the oxygen concentration in the tundish in order to prevent air oxidation of the molten steel in the tundish, which is the main cause of lowering the cleanliness of the molten steel. It is an object of the present invention to provide a method capable of efficiently reducing power consumption.
【０００５】[0005]
【課題を解決するための手段】本発明は、（１）鋼の連
続鋳造において、タンディッシュ内への溶鋼注入前に、
Ｍｇ合金をタンディッシュ内へ添加することを特徴とす
るタンディッシュ内溶鋼の清浄化方法である。また、
（２）鋼の連続鋳造において、タンディッシュ内への溶
鋼注入前に、Ｔｉ、Ｓｉ、Ｃｕ、Ｎｉ、Ｆｅの内少なく
とも一種類以上とＭｇからなる合金をタンディッシュ内
へ添加することを特徴とするタンディッシュ内溶鋼の清
浄化方法である。また、（３）鋼の連続鋳造において、
タンディッシュ内への溶鋼注入前に、Ｔｉ、Ｓｉ、Ｃ
ｕ、Ｎｉ、Ｆｅの内少なくとも一種類以上と１質量％か
ら８０質量％のＭｇからなる合金をタンディッシュ内へ
添加することを特徴とするタンディッシュ内溶鋼の清浄
化方法である。また、（４）鋼の連続鋳造において、タ
ンディッシュ内への溶鋼注入前に不活性ガスを吹き込む
ことを特徴とする上記（１）から（３）のいずれかの項
に記載のタンディッシュ内溶鋼の清浄化方法である。ま
た、（５）鋼の連続鋳造において、合金の粒径を１ｍｍ
以上２０ｍｍ以下としたことを特徴とする上記（１）か
ら（４）のいずれかの項に記載のタンディッシュ内溶鋼
の清浄化方法である。また、（６）溶鋼注入前のタンデ
ィッシュ内の酸素濃度を１％以下にしたことを特徴とす
る上記（１）から（５）のいずれかの項に記載のタンデ
ィッシュ内溶鋼の清浄化方法である。SUMMARY OF THE INVENTION The present invention relates to (1) continuous casting of steel, before molten steel is poured into a tundish,
This is a method for cleaning molten steel in a tundish, characterized by adding an Mg alloy into the tundish. Also,
(2) In the continuous casting of steel, an alloy consisting of at least one of Ti, Si, Cu, Ni and Fe and Mg is added into the tundish before injecting molten steel into the tundish. This is a method for cleaning molten steel in a tundish. (3) In continuous casting of steel,
Before injecting molten steel into the tundish, Ti, Si, C
A method for cleaning molten steel in a tundish, characterized by adding an alloy composed of at least one of u, Ni, and Fe and 1 to 80% by mass of Mg to the tundish. (4) In the continuous casting of steel, an inert gas is blown before injecting molten steel into the tundish, wherein the molten steel in the tundish according to any one of the above (1) to (3), Is a cleaning method. (5) In the continuous casting of steel, the grain size of the alloy is 1 mm.
The method for cleaning molten steel in a tundish according to any one of the above (1) to (4), characterized in that the thickness is not less than 20 mm. (6) The method for cleaning molten steel in a tundish according to any one of the above (1) to (5), wherein the oxygen concentration in the tundish before injecting the molten steel is set to 1% or less. It is.
【０００６】[0006]
【発明の実施の形態】一般に、取鍋からタンディッシュ
内に溶鋼を注入する際、取鍋に取り付けた溶鋼注入用ノ
ズルが湯面下に浸漬されるまでは注入流の攪拌エネルギ
ーが非常に大きいため、注入初期は溶鋼表面積が増大
し、（１）式の反応で示される空気酸化に起因して多数
の介在物が生成する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Generally, when molten steel is poured from a ladle into a tundish, the stirring energy of the injected flow is very large until the molten steel injection nozzle attached to the ladle is immersed below the surface of the molten metal. Therefore, the surface area of the molten steel increases in the initial stage of injection, and a large number of inclusions are generated due to the air oxidation shown by the reaction of the formula (1).
【０００７】 ４Ａｌ＋３Ｏ2＝２Ａｌ2Ｏ3 … （１） このように、注入初期の空気酸化速度は定常状態のそれ
に比べて極めて速く、タンディッシュにおける溶鋼汚染
の最大の原因となっている。本発明者らは、この注入初
期の空気酸化を防止するために、タンディッシュに蓋を
し、タンディッシュ内をＡｒガスで置換した上で、溶鋼
の注入を開始する方法について検討してきたが、従来の
タンディッシュ内へのＡｒガス吹き込み方法では、溶鋼
の酸化を防止できる程度まで酸素濃度を低減できないこ
とが分かった。4Al + 3O 2 = 2Al 2 O 3 (1) As described above, the air oxidation rate in the initial stage of injection is extremely faster than that in the steady state, and is the largest cause of molten steel contamination in the tundish. The present inventors have studied a method of starting the injection of molten steel after covering the tundish with Ar gas in order to prevent air oxidation at the initial stage of the injection, and replacing the inside of the tundish with Ar gas. It has been found that the conventional method of blowing Ar gas into a tundish cannot reduce the oxygen concentration to such an extent that the oxidation of molten steel can be prevented.
【０００８】図１は従来のタンディッシュシール方法を
説明するための図である。溶鋼注入に先だって、タンデ
ィッシュ１内の空気２をＡｒガス３で置換するために、
タンディッシュ蓋４に設けた取鍋５内溶鋼を溶鋼注入用
ノズル６を介して注入するための注入孔７にガス吹き込
み用ノズル８を設置し、ここからＡｒガス３をタンディ
ッシュ１内に吹き込んでいる。しかし、注入孔７を閉じ
ることは操業上困難であり、このためガス吹き込み用ノ
ズル８からタンディッシュ１内にＡｒガス３を吹き込む
と、Ａｒガス３噴流が周辺の空気２を巻き込み、タンデ
ィッシュ１内の酸素濃度は十分に低減できない。本発明
者らはガス吹き込み用ノズル８から吹き込まれたＡｒガ
ス３が巻き込む空気２の量を詳細に測定した結果、巻き
込み空気流量はＡｒガス流量の数倍にも達しており、タ
ンディッシュ内の酸素濃度低減には、この問題を解決す
ることが必須であることを見いだした。FIG. 1 is a view for explaining a conventional tundish sealing method. Prior to molten steel injection, to replace the air 2 in the tundish 1 with Ar gas 3,
A gas injection nozzle 8 is installed in an injection hole 7 for injecting molten steel in a ladle 5 provided on a tundish lid 4 through a molten steel injection nozzle 6, and Ar gas 3 is injected into the tundish 1 from here. In. However, it is difficult for the operation to close the injection hole 7. Therefore, when the Ar gas 3 is blown into the tundish 1 from the gas blowing nozzle 8, the Ar gas 3 jet entrains the surrounding air 2 and the tundish 1 The oxygen concentration in the interior cannot be reduced sufficiently. The present inventors measured the amount of air 2 entrained by the Ar gas 3 blown from the gas injection nozzle 8 in detail, and as a result, the flow rate of the entrained air reached several times the flow rate of the Ar gas. It has been found that solving this problem is essential for reducing the oxygen concentration.
【０００９】上記結果から、本発明者らは、タンディッ
シュ内へのＡｒガス吹き込み流量を低減する、或いは全
く実施しない状態でも、注入前のタンディッシュ内の酸
素濃度を効率的に低減できる方法について検討し、Ｍｇ
合金を注入前にタンディッシュ内に添加することが有効
であることを見いだした。Ｍｇ合金、例えばＭｇ−Ａｌ
合金を溶鋼の注入に先だってタンディッシュ内に添加す
ると、タンディッシュの予熱温度（１３００℃程度）で
Ａｌは溶解し、それと共にＭｇ（Ｍｇの沸点は約１１０
０℃）が蒸発する。このＭｇガスは、タンディッシュ内
の酸素と（２）式により反応するため、タンディッシュ
内の酸素濃度を低減することができる。From the above results, the present inventors have proposed a method for reducing the flow rate of Ar gas into the tundish or for efficiently reducing the oxygen concentration in the tundish before injection even without performing it at all. Consider, Mg
It has been found that it is effective to add the alloy into the tundish before pouring. Mg alloy, for example, Mg-Al
If the alloy is added to the tundish prior to injecting the molten steel, Al will melt at the preheating temperature of the tundish (about 1300 ° C.), and at the same time, Mg (Mg has a boiling point of about 110
0 ° C.) evaporates. Since this Mg gas reacts with oxygen in the tundish according to the equation (2), the oxygen concentration in the tundish can be reduced.
【００１０】２Ｍｇ＋Ｏ2＝ＭｇＯ … （２） タンディッシュ内におけるＭｇの蒸発は比較的速く進行
するため、Ｍｇ−Ａｌ合金の添加と共にタンディッシュ
内に多量のＭｇガスが発生し、タンディッシュ内は正圧
となる。その結果、Ａｒガス吹き込みによる外部からの
空気巻き込みも抑制され、短時間で効果的にタンディッ
シュ内の酸素濃度を低減することが可能となる。タンデ
ィッシュ内の酸素をＭｇＯとして固定するに十分なＭｇ
−Ａｌ合金を添加した場合には、従来のＡｒガス吹き込
みを併用しなくても、本発明だけで十分にタンディッシ
ュ内の酸素を低減できる。ここでは、Ｍｇ合金としてＭ
ｇ−Ａｌ合金を例に説明したが、Ｍｇを合金化する元素
はＡｌだけに限られたものではなく、Ｍｇと合金化でき
るもの、例えばＴｉ、Ｓｉ、Ｃｕ、Ｎｉ、Ｆｅでも良
く、或いはこの中から複数種類を含んでも良い。2Mg + O 2 = MgO (2) Since the evaporation of Mg in the tundish proceeds relatively quickly, a large amount of Mg gas is generated in the tundish with the addition of the Mg-Al alloy, and the inside of the tundish is positive. Pressure. As a result, the entrainment of air from the outside due to the blowing of the Ar gas is also suppressed, and the oxygen concentration in the tundish can be effectively reduced in a short time. Mg sufficient to fix oxygen in the tundish as MgO
When the Al alloy is added, oxygen in the tundish can be sufficiently reduced only by the present invention without using conventional Ar gas blowing. Here, M
Although the g-Al alloy has been described as an example, the element for alloying Mg is not limited to Al, but may be alloyable with Mg, for example, Ti, Si, Cu, Ni, Fe, or A plurality of types may be included.
【００１１】空気との反応によりＭｇ−Ａｌ合金中で生
成したＡｌ2Ｏ3は未反応のＭｇ−Ａｌ合金と一緒に、ま
た、Ｍｇ蒸気と空気との反応により生成したＭｇＯもガ
ス中でクラスター化し比較的大きな粒子となり、溶鋼の
注入と共に浮上分離するため、本発明により溶鋼の清浄
性が低下するといった問題は生じない。Ｍｇ合金中のＭ
ｇ含有率が８０質量％超になるとＭｇの蒸気圧が高くな
り過ぎるため、タンディッシュ内に添加すると一挙に反
応し、その後Ｍｇの蒸発反応が停滞するため、タンディ
ッシュ内の酸素濃度を低く維持できない。反対にＭｇ含
有率が１質量％未満になるとＭｇガスの供給速度が急激
に低下し、タンディッシュ内の酸素濃度を低減できなく
なる。このため、Ｍｇ合金中のＭｇ含有率は１質量％か
ら８０質量％にする必要がある。Ｍｇ合金の添加量は、
タンディッシュ容量やＡｒガス吹き込み流量との関係に
よりタンディッシュ内の酸素量が異なるため、一概には
規定できないが、基本的にはタンディッシュ内酸素量か
ら（２）式の化学量論的関係を用いて必要Ｍｇ量を決め
れば良い。なお、タンディッシュ内の酸素濃度が１％以
下になると溶鋼の空気酸化が防止されるため、Ｍｇ合金
の添加量はタンディッシュ内の酸素濃度が１％以下にな
るように規定した。Al 2 O 3 generated in the Mg—Al alloy by the reaction with air is mixed together with the unreacted Mg—Al alloy, and MgO generated by the reaction between the Mg vapor and the air is also clustered in the gas. The particles of the present invention become relatively large particles and float and separate with the injection of the molten steel. Therefore, the present invention does not cause a problem that the cleanliness of the molten steel is reduced. M in Mg alloy
If the g content exceeds 80% by mass, the vapor pressure of Mg becomes too high, and if added in a tundish, it reacts at once, and then the evaporation reaction of Mg stagnates, so that the oxygen concentration in the tundish is kept low. Can not. Conversely, when the Mg content is less than 1% by mass, the supply speed of the Mg gas is sharply reduced, and the oxygen concentration in the tundish cannot be reduced. Therefore, the Mg content in the Mg alloy needs to be 1% by mass to 80% by mass. The addition amount of Mg alloy
Since the amount of oxygen in the tundish differs depending on the relationship with the tundish capacity and the flow rate of Ar gas injection, it cannot be specified unconditionally. The necessary amount of Mg may be determined by using this. Since the air oxidation of the molten steel is prevented when the oxygen concentration in the tundish becomes 1% or less, the addition amount of the Mg alloy is specified so that the oxygen concentration in the tundish becomes 1% or less.
【００１２】Ｍｇ合金の粒径は１ｍｍ以上２０ｍｍ以下
にすることが好ましい。１ｍｍ未満の粒径ではＭｇの蒸
発速度が速くなり過ぎ溶鋼注入前にＭｇガスが全て発生
してしまうため、また２０ｍｍ超の粒径では（２）式の
反応速度が遅くなり過ぎＭｇガス量が不足するため、何
れもタンディッシュ内の酸素濃度を低減する機能が低下
する。また、Ｍｇ合金中には、ＭｇＯ、Ａｌ2Ｏ3等の酸
化物、ＡｌＮ、ＴｉＮ等の窒化物、或いはＭｇＳ等の硫
化物を１０質量％以下で含有しても良い。これは、不純
物の含有率が１０質量％を超えるとＭｇガスの供給速度
が低下し、タンディッシュ内の酸素濃度を低減する機能
が大きく低下するためである。The Mg alloy preferably has a particle size of 1 mm or more and 20 mm or less. If the particle diameter is less than 1 mm, the evaporation rate of Mg is too fast, and all the Mg gas is generated before the molten steel is injected. If the particle diameter is more than 20 mm, the reaction rate of the formula (2) becomes too slow, and the amount of Mg gas is too low. In all cases, the function of reducing the oxygen concentration in the tundish is reduced. Further, the Mg alloy may contain an oxide such as MgO or Al 2 O 3 , a nitride such as AlN or TiN, or a sulfide such as MgS at 10% by mass or less. This is because when the content of impurities exceeds 10% by mass, the supply rate of the Mg gas is reduced, and the function of reducing the oxygen concentration in the tundish is greatly reduced.
【００１３】[0013]
【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。 ＜実施例１＞容量５０ｔのタンディッシュに耐火性蓋を
した上で、内径２００ｍｍの溶鋼注入用ノズルをタンデ
ィッシュ底部から２００ｍｍの位置に設置した。タンデ
ィッシュへの溶鋼注入前に粒径１５ｍｍのＮｉ−１０質
量％Ｍｇ合金１０ｋｇをタンディッシュ内に添加した。
添加から２分後に、タンディッシュ内の酸素濃度は１％
以下となり安定したため、成分Ｃ：５０ｐｐｍ、Ｓｉ：
０．０１５％、Ｍｎ：０．２５％、Ｐ：０．０２％、
Ｓ：０．０１％、Ａｌ：０．０３５％、温度１５７０℃
の溶鋼２５０ｔを取鍋から２０ｔ／ｍｉｎで注入した。
この時、タンディッシュ出側の溶鋼中全酸素量は注入初
期から一定値を示し、安定して全酸素量１５ｐｐｍを確
保できた。これにより、溶鋼汚染は確実に防止でき、圧
延後の製品には表面欠陥は発生しなかった。 ＜実施例２＞容量５０ｔのタンディッシュに耐火性蓋を
した上で、内径２００ｍｍの溶鋼注入用ノズルをタンデ
ィッシュ底部から２００ｍｍの位置に設置し、タンディ
ッシュへの溶鋼注入前にＡｒガスを５０Ｎｍ3／ｈの流
量で吹き込んだ。同時に、粒径１０ｍｍで４０質量％Ｎ
ｉ−４０質量％Ｃｕ−２０質量％Ｍｇ合金６ｋｇをタン
ディッシュ内に添加した。添加から２分後に、タンディ
ッシュ内の酸素濃度は１％以下となり安定したため、成
分Ｃ：５０ｐｐｍ、Ｓｉ：０．０１５％、Ｍｎ：０．２
５％、Ｐ：０．０２％、Ｓ：０．０１％、Ａｌ：０．０
３５％、温度１５７０℃の溶鋼２５０ｔを取鍋から２０
ｔ／ｍｉｎで注入した。この時、タンディッシュ出側の
溶鋼中全酸素量は注入初期から一定値を示し、安定して
全酸素量１３ｐｐｍを確保できた。これにより、溶鋼汚
染は確実に防止でき、圧延後の製品には表面欠陥は発生
しなかった。 ＜比較例１＞容量５０ｔのタンディッシュに耐火性蓋を
した上で、内径２００ｍｍの溶鋼注入用ノズルをタンデ
ィッシュ底部から２００ｍｍの位置に設置し、タンディ
ッシュへの溶鋼注入前にＡｒガスを１５０Ｎｍ3／ｈの
流量で吹き込んだ。Ａｒガス吹き込み開始から１０分が
経過しても、タンディッシュ内の酸素濃度が８％以下に
ならなかったので、そのまま成分Ｃ：５０ｐｐｍ、Ｓ
ｉ：０．０１５％、Ｍｎ：０．２５％、Ｐ：０．０２
％、Ｓ：０．０１％、Ａｌ：０．０３５％、温度１５７
０℃の溶鋼２５０ｔを取鍋から２０ｔ／ｍｉｎで注入し
た。この時、タンディッシュ出側の溶鋼中全酸素量は注
入初期に９０ｐｐｍに達し、その後徐々に低下したが、
最終到達値は５０ｐｐｍであった。このため、注入初期
の汚染は防止できず、圧延後の製品には表面欠陥が発生
した。The present invention will be described below with reference to examples and comparative examples. <Example 1> A 50-ton capacity tundish was covered with a fire-resistant lid, and a molten steel injection nozzle having an inner diameter of 200 mm was set at a position 200 mm from the bottom of the tundish. Before injecting molten steel into the tundish, 10 kg of a Ni-10 mass% Mg alloy having a particle size of 15 mm was added into the tundish.
Two minutes after the addition, the oxygen concentration in the tundish is 1%
Since it became stable as below, component C: 50 ppm, Si:
0.015%, Mn: 0.25%, P: 0.02%,
S: 0.01%, Al: 0.035%, temperature 1570 ℃
Of molten steel was injected from a ladle at 20 t / min.
At this time, the total oxygen content in the molten steel on the tundish outlet side showed a constant value from the beginning of the injection, and a stable total oxygen content of 15 ppm was secured. Thereby, the molten steel contamination can be reliably prevented, surface defects did not occur in the product after rolling. <Example 2> A 50-ton capacity tundish was covered with a fire-resistant lid, and a 200-mm inside diameter nozzle for injecting molten steel was installed at a position 200 mm from the bottom of the tundish. Before injecting molten steel into the tundish, 50 Nm of Ar gas was injected. Blowing was performed at a flow rate of 3 / h. At the same time, 40 wt% in particle diameter 10 mm N
6 kg of i-40 mass% Cu-20 mass% Mg alloy was added into the tundish. Two minutes after the addition, the oxygen concentration in the tundish became 1% or less and stabilized, so that component C: 50 ppm, Si: 0.015%, and Mn: 0.2
5%, P: 0.02%, S: 0.01%, Al: 0.0
35%, temperature of 1570 ° C molten steel 250t from ladle 20
It was injected at t / min. At this time, the total oxygen content in the molten steel on the outlet side of the tundish showed a constant value from the initial stage of the injection, and the total oxygen content of 13 ppm was stably secured. As a result, molten steel contamination was reliably prevented, and no surface defects occurred in the product after rolling. <Comparative Example 1> A tundish having a capacity of 50 t was covered with a refractory lid, and a nozzle for injecting molten steel having an inner diameter of 200 mm was installed at a position 200 mm from the bottom of the tundish. It was blown at a flow rate of 3 / h. Even after 10 minutes from the start of the Ar gas injection, the oxygen concentration in the tundish did not become 8% or less.
i: 0.015%, Mn: 0.25%, P: 0.02
%, S: 0.01%, Al: 0.035%, temperature 157
250 t of molten steel at 0 ° C. was injected from the ladle at 20 t / min. At this time, the total oxygen content in the molten steel on the outlet side of the tundish reached 90 ppm in the initial stage of injection, and gradually decreased thereafter.
Ultimate value was 50ppm. For this reason, contamination at the initial stage of the injection could not be prevented, and surface defects occurred in the product after rolling.
【００１４】[0014]
【発明の効果】以上に説明したように、本発明のタンデ
ィッシュ内溶鋼の清浄化方法によれば、タンディッシュ
内の酸素濃度を迅速に、且つ効率的に低減できるため、
操業を乱すことなく、最も激しい注入初期の溶鋼汚染を
確実に防止でき、鋳片の品質も極めて向上する。As described above, according to the method for cleaning molten steel in a tundish of the present invention, the oxygen concentration in the tundish can be reduced quickly and efficiently.
Without disturbing the operation, the most severe contamination of molten steel in the early stage of pouring can be reliably prevented, and the quality of the slab is extremely improved.
【図１】第１図は従来のタンディッシュシール方法を説
明するための図である。FIG. 1 is a view for explaining a conventional tundish sealing method.
１…タンディッシュ ２…空気 ３…Ａｒガス ４…タンディッシュ蓋 ５…取鍋 ６…溶鋼注入用ノズル ７…注入孔 ８…ガス吹き込み用ノズル DESCRIPTION OF SYMBOLS 1 ... Tundish 2 ... Air 3 ... Ar gas 4 ... Tundish lid 5 ... Ladle 6 ... Nozzle for molten steel injection 7 ... Injection hole 8 ... Nozzle for gas injection
Claims (6)
内への溶鋼注入前に、Ｍｇ合金をタンディッシュ内へ添
加することを特徴とするタンディッシュ内溶鋼の清浄化
方法。1. A method for cleaning molten steel in a tundish, comprising adding an Mg alloy into a tundish before pouring molten steel into the tundish in continuous casting of steel.
内への溶鋼注入前に、Ｔｉ、Ｓｉ、Ｃｕ、Ｎｉ、Ｆｅの
内少なくとも一種類以上とＭｇからなる合金をタンディ
ッシュ内へ添加することを特徴とするタンディッシュ内
溶鋼の清浄化方法。2. In the continuous casting of steel, it is preferable to add an alloy comprising at least one of Ti, Si, Cu, Ni and Fe and Mg to the tundish before pouring molten steel into the tundish. Characteristic method for cleaning molten steel in tundish.
内への溶鋼注入前に、Ｔｉ、Ｓｉ、Ｃｕ、Ｎｉ、Ｆｅの
内少なくとも一種類以上と１質量％から８０質量％のＭ
ｇからなる合金をタンディッシュ内へ添加することを特
徴とするタンディッシュ内溶鋼の清浄化方法。3. In continuous casting of steel, at least one or more of Ti, Si, Cu, Ni and Fe and 1% by weight to 80% by weight of M are added before molten steel is poured into a tundish.
A method for cleaning molten steel in a tundish, comprising adding an alloy consisting of g into a tundish.
内への溶鋼注入前に不活性ガスを吹き込むことを特徴と
する請求項１から３のいずれかの項に記載のタンディッ
シュ内溶鋼の清浄化方法。4. The cleaning of molten steel in a tundish according to claim 1, wherein in the continuous casting of steel, an inert gas is blown before injecting the molten steel into the tundish. Method.
ｍｍ以上２０ｍｍ以下としたことを特徴とする請求項１
から４のいずれかの項に記載のタンディッシュ内溶鋼の
清浄化方法。5. In continuous casting of steel, the grain size of the alloy is set to 1
2. The thickness is set to not less than 20 mm and not more than 20 mm.
5. The method for cleaning molten steel in a tundish according to any one of the above items.
度を１％以下にしたことを特徴とする請求項１から５の
いずれかの項に記載のタンディッシュ内溶鋼の清浄化方
法。6. The method for cleaning molten steel in a tundish according to claim 1, wherein the oxygen concentration in the tundish before injecting the molten steel is set to 1% or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001072429A JP2002263808A (en) | 2001-03-14 | 2001-03-14 | Method for cleaning molten steel in tundish |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001072429A JP2002263808A (en) | 2001-03-14 | 2001-03-14 | Method for cleaning molten steel in tundish |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002263808A true JP2002263808A (en) | 2002-09-17 |
Family
ID=18930013
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001072429A Withdrawn JP2002263808A (en) | 2001-03-14 | 2001-03-14 | Method for cleaning molten steel in tundish |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002263808A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170023559A (en) | 2015-08-24 | 2017-03-06 | 주식회사 포스코 | Manufacturing method for molten metal |
| KR20170025113A (en) | 2015-08-27 | 2017-03-08 | 주식회사 포스코 | Casting apparatus and method thereof |
| KR20170024800A (en) | 2015-08-26 | 2017-03-08 | 주식회사 포스코 | Nozzle and continuous casting method of using the same |
-
2001
- 2001-03-14 JP JP2001072429A patent/JP2002263808A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170023559A (en) | 2015-08-24 | 2017-03-06 | 주식회사 포스코 | Manufacturing method for molten metal |
| KR101742076B1 (en) * | 2015-08-24 | 2017-05-31 | 주식회사 포스코 | Manufacturing method for molten metal |
| KR20170024800A (en) | 2015-08-26 | 2017-03-08 | 주식회사 포스코 | Nozzle and continuous casting method of using the same |
| KR20170025113A (en) | 2015-08-27 | 2017-03-08 | 주식회사 포스코 | Casting apparatus and method thereof |
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