JPH08215805A - Production of clean steel - Google Patents
Production of clean steelInfo
- Publication number
- JPH08215805A JPH08215805A JP2851795A JP2851795A JPH08215805A JP H08215805 A JPH08215805 A JP H08215805A JP 2851795 A JP2851795 A JP 2851795A JP 2851795 A JP2851795 A JP 2851795A JP H08215805 A JPH08215805 A JP H08215805A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- tundish
- inclusions
- steel
- inert 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.)
- Pending
Links
Landscapes
- Continuous Casting (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は普通鋼、ステンレス鋼等
の金属溶湯を連続鋳造する際に用いるタンディシュにお
いて、溶鋼中の介在物の浮上分離を促進することによっ
て、清浄鋼を製造するための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 tundish used for continuous casting of molten metal such as ordinary steel and stainless steel, for producing clean steel by promoting floating separation of inclusions in molten steel. It is about the method.
【０００２】[0002]
【従来の技術】連続鋳造等において、金属溶湯を鋳型に
注入する前に、タンディシュのような溶鋼収納容器を使
用している。その使用により介在物浮上が促進されるた
め従来から広く利用されている。従来、タンディシュで
は大型化等の形状適性化によって介在物を自然浮上させ
る領域を増加させ、介在物に浮上促進を図ってきた。こ
れらの方法によりかなりの介在物を浮上除去することが
可能となっている。 しかしながら、タンディシュの形
状だけでは自ずと限界があり、品質欠陥となる介在物を
皆無にすることはできない。即ち、介在物が自力浮上可
能な介在物径は１００μｍ以上程度であり、それ以下の
介在物は鋳型内に侵入し、凝固層に捕捉されるおそれが
ある。2. Description of the Related Art In continuous casting or the like, a molten steel container such as a tundish is used before pouring a molten metal into a mold. Since its use promotes floating of inclusions, it has been widely used. Conventionally, in the tundish, the area where the inclusions are allowed to float naturally has been increased by optimizing the shape such as increasing the size, and the floating of the inclusions has been promoted. By these methods, it is possible to float and remove a considerable amount of inclusions. However, the tundish shape alone has a limit, and it is impossible to completely eliminate inclusions that cause quality defects. That is, the diameter of the inclusions that allow the inclusions to float by themselves is about 100 μm or more, and inclusions smaller than that size may enter the mold and be trapped in the solidified layer.
【０００３】そのため、介在物系の品質欠陥を皆無にす
るためには、上記の方法では浮上しなかった介在物につ
いても浮上させる施策が必要となる。そのための方法と
して、例えば特開昭５８−５８９６５号公報の如く、溶
鋼中に不活性ガスを吹き込み、Ａｒ等の不活性ガスが接
触する部位の溶鋼流速を２０〜８０cm/secとすることに
より微細気泡を溶鋼中に発生させ、微小介在物を浮上除
去する方法が知られている。Therefore, in order to eliminate the quality defects of the inclusion system, it is necessary to take measures to float even the inclusions that did not float by the above method. As a method therefor, for example, as disclosed in Japanese Patent Laid-Open No. 58-58965, by injecting an inert gas into molten steel and setting the molten steel flow velocity at a portion in contact with an inert gas such as Ar to 20 to 80 cm / sec, A method is known in which bubbles are generated in molten steel to float and remove fine inclusions.
【０００４】[0004]
【発明が解決しようとする課題】介在物の径が１００μ
ｍ以下の微小介在物を浮上除去するために、先に述べた
如く、特開昭５８−５８９６５号公報の方法が知られて
いるが、このような方法でも依然として品質欠陥となる
介在物を皆無にすることができない。本発明はこのよう
な問題点を解消する清浄鋼の製造方法を提供することを
目的とするものである。The diameter of inclusions is 100 μm.
As described above, the method disclosed in Japanese Patent Laid-Open No. 58-58965 is known in order to float and remove fine inclusions of m or less. However, even with such a method, there are still no inclusions that cause quality defects. I can't. It is an object of the present invention to provide a method for producing clean steel that solves such problems.
【０００５】[0005]
【課題を解決するための手段】本発明の要旨は清浄鋼を
製造する際にタンディシュ内の溶鋼の流速を０．４m/s
以上とし、該溶鋼に不活性ガスをタンディシュに設けた
多孔質耐火物を介して１０〜５０Ｎリットル／min の流
量で吹き込むことを特徴とする清浄鋼の製造方法にあ
る。即ち、本発明は清浄鋼を得るために、タンディシュ
内の溶鋼に不活性ガスを吹き込み、微小介在物を浮上除
去するものであるが、その際に溶鋼の流速を高めると共
に不活性ガスの吹き込み流量を多くし、この双方の要件
を満足することにより介在物の浮上除去効果が極めて大
きくなるとする知見によりなされたものである。SUMMARY OF THE INVENTION The gist of the present invention is to provide a molten steel flow velocity in a tundish of 0.4 m / s when producing clean steel.
The above is a method for producing clean steel, characterized in that an inert gas is blown into the molten steel through a porous refractory provided in a tundish at a flow rate of 10 to 50 Nl / min. That is, in order to obtain clean steel, the present invention blows an inert gas into the molten steel in the tundish to float and remove fine inclusions.At that time, the flow rate of the molten steel is increased and the flow rate of the inert gas is increased. It was made based on the finding that the floating removal effect of inclusions becomes extremely large by satisfying both requirements.
【０００６】次に本発明を図１〜図５を用いて詳細に説
明する。先ず、図１（ａ）において、タンディシュｔの
１の部位に取鍋から溶鋼が供給され、タンディシュ内を
通り、ノズル２より鋳型へ溶鋼が供給される。その途中
に多孔質耐火物４を設置し、ガス供給管５より不活性ガ
ス（例えば、Ａｒガス）を吹き込む。この際、多孔質性
耐火物４は図１（ｂ）の如く、タンディシュｔの底部に
設置し下吹きする方法と、図１（ｃ）の如く、堰３の下
部に設置し上吹きする方法がある。どちらの方法でも本
発明の効果は得られるものであるが、図１（ｃ）の方法
であると、設置が容易であり、更に鋳造末期において、
スラグによる目詰まりを起こしにくいことから長寿命化
が期待でき、より好ましいものである。Next, the present invention will be described in detail with reference to FIGS. First, in FIG. 1 (a), molten steel is supplied from a ladle to the part 1 of the tundish t, passes through the inside of the tundish, and is supplied from the nozzle 2 to the mold. A porous refractory 4 is installed on the way, and an inert gas (for example, Ar gas) is blown from the gas supply pipe 5. At this time, the porous refractory material 4 is installed at the bottom of the tundish t as shown in FIG. 1 (b) and downward sprayed, or as installed at the bottom of the weir 3 as shown in FIG. 1 (c) and sprayed upward. There is. The effect of the present invention can be obtained by either method, but with the method of FIG. 1 (c), installation is easy, and at the end of casting,
Since it is unlikely to cause clogging due to slag, it can be expected to have a long life, which is more preferable.
【０００７】尚、タンディシュ内の溶鋼の流速を速める
手段としては特に、特定するものではないが、例えば、
図１に示したように、堰３を設け、流路断面積を小さく
し、不活性ガスの吹き込み部における溶鋼流速を大きく
する方法が好ましいものである。The means for increasing the flow velocity of the molten steel in the tundish is not particularly specified, but for example,
As shown in FIG. 1, it is preferable to provide a weir 3, reduce the flow passage cross-sectional area, and increase the molten steel flow velocity in the inert gas blowing portion.
【０００８】また、図２は溶鋼流速と多孔質耐火物の細
孔径がＡｒガスの平均気泡径に及ぼす影響を示すもので
あるが、Ａｒガスを溶鋼中で微細な状態（１０mm以下）
にするためには、多孔質耐火物の細孔径を２０μｍ以下
とするものである。尚、図２はオフラインのヒューズド
メタル実験で得られた結果に基づき、溶鋼の場合に換算
したものである。かくすることにより、溶鋼の流速を
０．４m/s 以上とし、吹き込みガスを溶鋼中に微細な状
態（１０mm以下）にすることが可能となるものである。FIG. 2 shows the influence of the molten steel flow velocity and the pore diameter of the porous refractory material on the average bubble diameter of Ar gas. Ar gas is in a fine state (10 mm or less) in molten steel.
In order to achieve this, the pore diameter of the porous refractory material is set to 20 μm or less. In addition, FIG. 2 is converted into the case of molten steel based on the result obtained in the offline fused metal experiment. By doing so, the flow velocity of the molten steel can be 0.4 m / s or more, and the blown gas can be made into a fine state (10 mm or less) in the molten steel.
【０００９】更に、本発明は溶鋼中の介在物を品質欠陥
のないようにするために、吹き込みガスを微細化するだ
けでなく、吹き込み量を特定するようにしたものであ
る。◎図３に吹き込みガス量と溶鋼流速が介在物浮上率
に及ぼす影響を示すものであるが、介在物の浮上率を高
めるためには溶鋼流速を０．４m/s 以上とするととも
に、吹き込みガス流量を１０Ｎリットル/min以上とする
ことが明らかである。しかし、吹き込みガス流量が多す
ぎるとボイリング等によりスラブを巻き込み、かえって
鋳片品質を悪化させるため、その上限を５０Ｎリットル
/minとする。尚、多孔質耐火物の寿命の点から背圧は
０．５kg／cm2 以下とすることが望ましい。Further, in order to prevent inclusions in molten steel from having quality defects, the present invention not only refines the blowing gas but also specifies the blowing amount. ◎ Fig. 3 shows the influence of the amount of blown gas and the flow rate of molten steel on the levitation rate of inclusions. To increase the levitation rate of inclusions, the flow rate of molten steel should be 0.4 m / s or more, and the blown gas It is clear that the flow rate is 10 N liter / min or more. However, if the blowing gas flow rate is too high, the slab will be entrained by boiling and the like, which will rather deteriorate the quality of the slab, so the upper limit is 50 Nl.
/ min. The back pressure is preferably 0.5 kg / cm 2 or less from the viewpoint of the life of the porous refractory material.
【００１０】[0010]
【実施例】次に本発明の実施例について述べる。図４に
示すタンディシュを用いて、多孔質耐火物としてアルミ
ナ質で作成したもの（平均細孔径１３μｍ）を用い、極
低炭素鋼において鋳造を実施した。◎平均鋳造速度７．
５ton/min 、溶鋼流速を０．４m/s 、Ａｒ流量１０Ｎリ
ットル／min 背圧０．５ｋg/cm2 で実施したモールド内
酸素源（トータル酸素）の推移を図５に示す。図５から
明らかなように、本発明によればモールド内トータル酸
素が少なく、非常に溶鋼清浄性の良好な鋳片が得られる
ものである。Next, an embodiment of the present invention will be described. Using the tundish shown in FIG. 4, a porous refractory material made of alumina (average pore diameter 13 μm) was used to perform casting on ultra-low carbon steel. ◎ Average casting speed 7.
FIG. 5 shows the transition of the oxygen source (total oxygen) in the mold, which was carried out at 5 ton / min, the molten steel flow rate was 0.4 m / s, the Ar flow rate was 10 Nl / min, and the back pressure was 0.5 kg / cm 2 . As is apparent from FIG. 5, according to the present invention, the total oxygen in the mold is small, and a slab having extremely good cleanliness of molten steel can be obtained.
【００１１】[0011]
【発明の効果】本発明の如く、タンディシュ内の溶鋼の
流速と該溶鋼に吹き付ける不活性ガスの流量の双方の条
件を特定することにより、品質欠陥となる介在物を皆無
にすることができ、その効果は極めて大きいものであ
る。As in the present invention, by specifying the conditions of both the flow rate of the molten steel in the tundish and the flow rate of the inert gas sprayed on the molten steel, inclusions that cause quality defects can be eliminated. The effect is extremely large.
【図１】図１（ａ）は本発明に用いるタンディシュの平
面図、（ｂ）は本発明に用いるタンディシュにおける不
活性ガスの下吹き法の説明図、（ｃ）は本発明に用いる
タンディシュにおける不活性ガスの上吹き法の説明図。FIG. 1 (a) is a plan view of a tundish used in the present invention, (b) is an explanatory view of an underflow method of an inert gas in a tundish used in the present invention, and (c) is a tundish used in the present invention. Explanatory drawing of the top blowing method of an inert gas.
【図２】溶鋼流速と多孔質耐火物の細孔径がＡｒガスの
平均気泡径に及ぼす影響を示す図。FIG. 2 is a diagram showing the influence of the molten steel flow velocity and the pore size of a porous refractory material on the average bubble size of Ar gas.
【図３】吹き込みガス量と溶鋼流速が介在物浮上率に及
ぼす影響を示す図。FIG. 3 is a diagram showing the influence of the blown gas amount and the molten steel flow rate on the inclusion levitation rate.
【図４】本発明の実施例に用いたタンディシュを示す
図。FIG. 4 is a diagram showing a tundish used in an example of the present invention.
【図５】本発明の実施例によるモールド内トータル酸素
を示す図である。FIG. 5 is a diagram showing total oxygen in a mold according to an example of the present invention.
１ 溶鋼の供給部 ２ ノズル ３ 堰 ４ 多孔質耐火物 ５ ガス供給管 ｔ タンディシュ 1 Molten Steel Supply Section 2 Nozzle 3 Weir 4 Porous Refractory 5 Gas Supply Pipe t Tundish
【手続補正書】[Procedure amendment]
【提出日】平成７年６月１４日[Submission date] June 14, 1995
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】図面[Document name to be corrected] Drawing
【補正対象項目名】図１[Name of item to be corrected] Figure 1
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【図１】 FIG.
Claims (1)
の溶鋼の流速を０．４m/s 以上とし、該溶鋼に不活性ガ
スをタンディシュに設けた多孔質耐火物を介して１０〜
５０Ｎリットル／min の流量で吹き込むことを特徴とす
る清浄鋼の製造方法。1. When producing clean steel, the flow rate of the molten steel in the tundish is set to 0.4 m / s or more, and an inert gas is added to the molten steel in the tundish through a porous refractory material for 10 to 10 times.
A method for producing clean steel, which comprises blowing at a flow rate of 50 Nl / min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2851795A JPH08215805A (en) | 1995-02-16 | 1995-02-16 | Production of clean steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2851795A JPH08215805A (en) | 1995-02-16 | 1995-02-16 | Production of clean steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08215805A true JPH08215805A (en) | 1996-08-27 |
Family
ID=12250883
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2851795A Pending JPH08215805A (en) | 1995-02-16 | 1995-02-16 | Production of clean steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08215805A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11203059B2 (en) | 2017-07-14 | 2021-12-21 | Posco | Molten material treatment apparatus |
-
1995
- 1995-02-16 JP JP2851795A patent/JPH08215805A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11203059B2 (en) | 2017-07-14 | 2021-12-21 | Posco | Molten material treatment apparatus |
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