JP3282105B2 - Cleaning method for molten steel in tundish - Google Patents
Cleaning method for molten steel in tundishInfo
- Publication number
- JP3282105B2 JP3282105B2 JP04059994A JP4059994A JP3282105B2 JP 3282105 B2 JP3282105 B2 JP 3282105B2 JP 04059994 A JP04059994 A JP 04059994A JP 4059994 A JP4059994 A JP 4059994A JP 3282105 B2 JP3282105 B2 JP 3282105B2
- Authority
- JP
- Japan
- Prior art keywords
- tundish
- molten steel
- injection
- inclusions
- 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
Landscapes
- Continuous Casting (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Description
【０００１】[0001]
【産業上の利用分野】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の注入を開始する際、
介在物除去速度を速めることにより、鋳込み初期の溶鋼
汚染の影響をすみやかに低減し、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 The present invention relates to a method for starting the injection of molten steel from a ladle into a tundish in continuous casting of steel.
The present invention relates to a method for purifying molten steel in a tundish by rapidly reducing the influence of molten steel contamination in the early stage of casting by increasing the removal rate of inclusions.
【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。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.
【０００３】その機能は、鋳型内への溶鋼供給量の調
節、溶鋼貯蔵、介在物の分離除去等である。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。[0003] Its functions are to control the supply of molten steel into a mold, to store molten steel, and to separate and remove inclusions. In particular, the function of removing inclusions has become an extremely important function with the recent strictness of steel material quality.
【０００４】しかし、取鍋からタンディッシュに溶鋼を
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。However, when pouring molten steel from a ladle into a 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.
【０００５】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種々の方法が検討され、実用化さ
れている。For this reason, various methods have been studied for the purpose of preventing molten steel contamination in a tundish and have been put to practical use.
【０００６】例えば、特開昭５９―１０５５号公報に記
載されているように、耐火ボード蓋で覆われたタンディ
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。For example, as described in JP-A-59-1055, air oxidation of injected molten steel is prevented by blowing an inert gas into a tundish covered with a refractory board lid. I have.
【０００７】また、特開昭６０―２６１６５１号公報で
は、取鍋から溶鋼を注入する際のタンディッシュ内の湯
面上昇速度を限定することにより空気巻き込み量を減少
させ空気酸化を抑制する方法、特開昭６１―３８７４９
号公報では、取鍋からタンディッシュに溶鋼を移送する
取鍋ロングノズルからＣａ系合金或はＣａ系フラックス
を添加することにより溶鋼中の介在物を効率的に除去す
る方法が提案され、或程度の効果を発揮している。Japanese Unexamined Patent Application Publication No. Sho 60-261651 discloses a method for suppressing air oxidation by reducing the amount of air entrapment by limiting the rising rate of the molten metal level in a tundish when pouring molten steel from a ladle. JP-A-61-38749
In the gazette, a method of efficiently removing inclusions in molten steel by adding a Ca-based alloy or a Ca-based flux from a ladle long nozzle for transferring molten steel from a ladle to a tundish has been proposed. The effect has been demonstrated.
【０００８】[0008]
【発明が解決しようとする課題】しかしながら、タンデ
ィッシュを耐火ボード蓋で覆い不活性ガスでシールする
方法については、タンディッシュや耐火ボード自体が高
温で変形するため、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分圧を低減することはできない。However, in the method of covering the tundish with a fireproof board lid and sealing with an inert gas, the tundish and the fireproof board themselves are deformed at a high temperature, so that the tundish can be prevented to the extent that air oxidation can be prevented. The oxygen partial pressure in the dish cannot be reduced.
【０００９】また、鋳込初期の注入流により巻き込まれ
た空気気泡は非常に微細であるため、反応界面積が大き
くなり、空気酸化速度は定常時の注入流に比べて格段に
速い。Further, since air bubbles entrained by the injection flow at the initial stage of casting are very fine, the reaction interface area becomes large, and the air oxidation rate is remarkably faster than that of the injection flow in a steady state.
【００１０】このため、鋳込初期においてタンディッシ
ュ内の湯面上昇速度を限定する方法は、空気酸化を幾分
抑制する効果があるものの十分な汚染防止対策にはなっ
ていない。For this reason, the method of limiting the rate of rise of the molten metal level in the tundish in the early stage of casting has the effect of suppressing air oxidation to some extent, but does not provide sufficient pollution prevention measures.
【００１１】さらに、取鍋ロングノズルからＣａ系合金
或はＣａ系フラックスを添加する方法は、介在物除去速
度を速める効果を有するものの、浮上した介在物が再び
注入流により巻き込まれるため、十分な溶鋼清浄性を確
保するには至っていない。Further, although the method of adding a Ca-based alloy or a Ca-based flux from a ladle long nozzle has the effect of increasing the removal rate of inclusions, the inclusions that have floated are again caught by the injection flow. The cleanliness of molten steel has not yet been secured.
【００１２】これらの問題を鑑み、本発明は、耐火ボー
ド蓋等の大がかりな設備を必要とせず、簡便な方法で最
も激しい鋳込初期の溶鋼汚染をすみやかに低減し、さら
にタンディッシュにおける介在物除去効果をも向上させ
るタンディッシュ内溶鋼の清浄化方法を提示することを
目的とするものである。In view of these problems, the present invention does not require a large-scale facility such as a refractory board lid, and can quickly reduce the most severe molten steel contamination in the early stage of casting by a simple method. It is an object of the present invention to provide a method for cleaning molten steel in a tundish that also improves the removal effect.
【００１３】[0013]
【課題を解決するための手段】取鍋からタンディシュに
溶鋼を注入する際、注入点直下のタンディシュ底部から
不活性ガスを吹き込むと共に、湯面を溶融性保温剤で被
覆することを特徴とするタンディシュ内溶鋼の清浄化方
法に関するものである。 When injecting molten steel from a ladle into a tundish, an inert gas is blown from the bottom of the tundish immediately below the injection point , and the molten metal surface is covered with a meltable heat insulating agent. The present invention relates to a method for cleaning internal molten steel .
【００１４】[0014]
【００１５】[0015]
【作用】一般に、取鍋からタンディッシュ内に溶鋼の注
入を開始すると、取鍋ロングノズルが湯面下に浸漬され
るまで、注入流は雰囲気中の酸素を多量に巻き込むた
め、溶鋼中には（１）式の反応で示される空気酸化に起
因する多数の介在物が生成する。[Function] In general, when pouring molten steel from the ladle into the tundish, the pouring flow involves a large amount of oxygen in the atmosphere until the ladle long nozzle is immersed below the surface of the molten metal. A large number of inclusions are generated due to the air oxidation shown by the reaction of the formula (1).
【００１６】[0016]
【化１】 ４Ａｌ（溶鋼中）＋３Ｏ2（空気中）＝２Ａｌ2Ｏ3（介在物） （１）Embedded image 4 Al (in molten steel) + 3O 2 (in air) = 2Al 2 O 3 (inclusions) (1)
【００１７】さらに、酸素は非常に微細な気泡として溶
鋼中に巻き込まれるため、その酸化速度は定常注入時の
酸化速度やスラグとの反応速度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。Furthermore, since oxygen is entrained in the molten steel as very fine bubbles, its oxidation rate is extremely faster than the oxidation rate during steady injection and the reaction rate with slag, and the maximum rate of molten steel contamination in the tundish is high. Cause.
【００１８】そこで、本発明者等らは、この鋳込初期の
空気酸化で生成した介在物及び取鍋から持ち込まれた介
在物の浮上分離を促進する方法について種々の検討を行
った結果、タンディッシュ底部から不活性ガスを吹き込
むと共に、湯面を溶融性保温剤で被覆することにより解
決できることを見いだした。Therefore, the present inventors have conducted various studies on a method for promoting the floating separation of the inclusions generated by the air oxidation in the early stage of casting and the inclusions brought in from the ladle. It has been found that the problem can be solved by blowing an inert gas from the bottom of the dish and coating the molten metal surface with a fusible heat insulating agent.
【００１９】図１は、更に詳細に説明するための図であ
る。予めタンデッシュ１に溶融性保温剤２を入れ置き
し、取鍋３から溶鋼４の注入を開始する際、タンデッシ
ュ底部６からＡｒ気泡９を溶鋼４中に吹き込む。[0019] FIG. 1 is a diagram for explaining further in detail. The meltable heat insulating agent 2 is put in the tundish 1 in advance, and when the injection of the molten steel 4 from the ladle 3 is started, Ar bubbles 9 are blown into the molten steel 4 from the bottom 6 of the tundish.
【００２０】このＡｒ気泡９吹き込みの攪拌力により介
在物の凝集合体が促進されると共に、気泡自身も周囲に
介在物を付着させるため、Ａｒガス吹き込みは介在物の
浮上分離速度を速める効果を有する。The agitation force of the blowing of the Ar bubbles 9 promotes the agglomeration and coalescence of the inclusions, and the bubbles themselves also cause the inclusions to adhere to the surroundings. Therefore, the Ar gas blowing has the effect of increasing the floating separation speed of the inclusions. .
【００２１】しかし、湯面が被覆されていない場合や介
在物を吸収できない固体保温剤が使用されている場合に
は、湯面付近でＡｒ気泡９の破裂に起因する介在物の再
巻き込みが生じるため、介在物濃度の到達値は改善され
ない。However, when the surface of the molten metal is not covered or when a solid heat insulating agent that cannot absorb inclusions is used, inclusions are re-engaged near the molten surface due to the burst of the Ar bubbles 9. Therefore, the attained value of the inclusion concentration is not improved.
【００２２】これに対し、溶鋼温度以下で液相が生成す
る溶融性保温剤２を使用すると介在物吸収能が高くな
り、浮上してきた介在物を確実に保温剤２中に吸収でき
るため、介在物濃度の到達値を従来よりも低下し清浄性
を高めることが可能となる。On the other hand, the use of the fusible heat insulating agent 2 which generates a liquid phase at a temperature lower than the temperature of the molten steel increases the inclusion absorbing ability and can reliably absorb the floating inclusions into the heat insulating agent 2. It is possible to reduce the ultimate value of the substance concentration and improve the cleanliness as compared with the related art.
【００２３】図３は、Ａｒガス吹き込みの効果と保温剤
の効果をるつぼ実験により求めた結果である。FIG. 3 shows the results of the effects of the Ar gas blowing and the effect of the heat insulating agent determined by crucible experiments.
【００２４】図から分かるように、Ａｒガス吹き込みは
全酸素量（介在物濃度）の減少速度を速める効果を、溶
融性保温剤の使用は全酸素量（介在物濃度）の到達値を
下げる効果を持つ。As can be seen from the figure, blowing Ar gas has the effect of increasing the rate of reduction of the total oxygen content (inclusion concentration), and the use of a fusible heat-reducing agent has the effect of lowering the ultimate value of the total oxygen content (inclusion concentration). have.
【００２５】また、溶融性保温剤は溶鋼を均一に被覆す
るため、空気酸化による汚染を抑制する効果も有してい
る。Further, since the meltable heat insulating agent covers the molten steel uniformly, it has an effect of suppressing contamination due to air oxidation.
【００２６】したがって、これらをタンディッシュ内で
併用することにより、鋳込み初期の空気酸化による影響
を低減すると共に、タンディッシュにおける介在物除去
効果をも向上できる。Therefore, by using these together in the tundish, it is possible to reduce the influence of air oxidation in the early stage of casting and to improve the effect of removing inclusions in the tundish.
【００２７】溶融性保温剤としては、できるだけ粘性が
低く介在物吸収能に優れたものが有効であるが、低粘性
の溶融性保温剤はタンディッシュ耐火物を激しく溶損す
るため、耐火物溶損が問題とならない範囲で低粘性化を
図る必要がある。It is effective to use a low-viscosity fusible insulating material which is as viscous as possible and excellent in the ability to absorb inclusions. It is necessary to reduce the viscosity within a range where does not cause a problem.
【００２８】また、保温剤中にＳｉＯ2等の低級酸化物
が多く含有されている場合、溶鋼中のＡｌと反応し介在
物を生成するため保温剤からの溶鋼汚染が生じる。Further, when the heat insulator contains a large amount of lower oxides such as SiO 2, it reacts with Al in the molten steel to generate inclusions, thereby causing contamination of the molten steel from the heat insulator.
【００２９】このため、保温剤中の低級酸化物の含有率
をできるだけ少なくすることが有効である。For this reason, it is effective to reduce the content of the lower oxide in the heat insulating agent as much as possible.
【００３０】ここに溶融性保温剤としては、ＣａＯ＋Ａ
ｌ2Ｏ3、ＣａＯ＋Ａｌ2Ｏ3＋ＭｇＯ等のものが好都合で
ある。Here, CaO + A is used as the melting heat insulating agent.
l 2 O 3, CaO + Al 2 O 3 + things such as MgO is convenient.
【００３１】保温剤の添加方法については、上記説明の
ように溶鋼注入を開始する以前に入れ置きする方法以外
に、溶鋼注入開始時に湯面上に添加する方法でも同様の
効果が得られる。Regarding the method of adding the heat insulating agent, the same effect can be obtained by adding the heat retaining agent to the molten steel surface at the start of the molten steel injection, in addition to the method of placing it before starting the injection of the molten steel as described above.
【００３２】一方、タンディッシュ底部における不活性
ガス吹き込み位置は、取鍋からタンディッシュへの溶鋼
注入点から浸漬ノズル配置位置までの間が良く、好まし
くはタンディッシュの幅方向全幅に亘ってポーラスプラ
グ８を設けＡｒ等の不活性ガスを吹き込む。On the other hand, the inert gas blowing position at the bottom of the tundish is preferably between the molten steel injection point from the ladle to the tundish and the position of the immersion nozzle, and preferably the porous plug extends over the entire width of the tundish in the width direction. 8 is provided, and an inert gas such as Ar is blown therein.
【００３３】この不活性ガスは微細であるほど介在物浮
上に効果があり、１０ｍｍφ以下の気泡として吹き込む
ことが好ましい。The finer the inert gas, the more effective it is at floating inclusions, and it is preferable that the inert gas be blown as bubbles having a diameter of 10 mm or less.
【００３４】また、不活性ガスの吹き込み流量は５〜１
００Ｎｌ／ｍｉｎ程度が好ましい。The blowing flow rate of the inert gas is 5 to 1
About 00Nl / min is preferable.
【００３５】すなわち、５Ｎｌ／ｍｉｎ未満では介在物
浮上効果が少なく、また１００Ｎｌ／ｍｉｎ超では溶鋼
のボイングが激しくなり過ぎるため好ましくない。That is, if it is less than 5 Nl / min, the effect of floating inclusions is small, and if it is more than 100 Nl / min, boring of the molten steel becomes too severe, which is not preferable.
【００３６】特に、タンデッシュ底部からのガス吹き込
みを本発明の図２に示すように注入直下で実施すれば、
注入流の攪拌力により気泡の微細化が促進され、介在物
の除去効率が向上する。In particular, if the gas is blown from the bottom of the tundish just below the injection as shown in FIG. 2 of the present invention ,
The stirring force of the injection flow promotes the miniaturization of bubbles, and improves the efficiency of removing inclusions.
【００３７】このため、設備上の制約がない場合には、
溶鋼の清浄化にとってガス吹き込み位置を注入点直下に
することが、最も効率的なガス吹き込み方法となる。For this reason, when there are no restrictions on equipment,
For cleaning the molten steel, setting the gas injection position immediately below the injection point is the most efficient gas injection method.
【００３８】さらに、鋳込み初期の最も溶鋼汚染が激し
い場合だけでなく、鋳造全域に渡って本発明を適用する
ことは十分可能であり、全体の鋳片品質を向上させるた
めにも有効な方法である。Furthermore, the present invention can be applied not only when the molten steel contamination is most severe at the beginning of casting, but also over the entire casting area, and is an effective method for improving the quality of the entire slab. is there.
【００３９】[0039]
【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。The present invention will be described below with reference to examples and comparative examples.
【００４０】[0040]
【比較例１】ＣａＯ：５０％、Ａｌ2 Ｏ3 ：５０％、融
点１４００℃の溶融性保温剤を図１に示す容量５０ｔの
タンディッシュ１（深さ１．０×幅２．０×長さ８．０
ｍ）内に予め入れ置きした。該タンディッシュ１はその
底部６に不活性ガス供給管７に接続されたガス吹き込み
用ボーラスプラグ８が浸漬ノズル１０に至る溶鋼流路の
途中に設けてある。[Comparative Example 1] CaO: 50%, Al 2 O 3: 50%, the tundish 1 (depth 1.0 × width 2.0 × length of capacity 50t shown in FIG. 1 the melting point 1400 ° C. meltable thermal insulation agent 8.0
m). The tundish 1 has a gas injection bolus plug 8 connected to an inert gas supply pipe 7 at the bottom 6 in the middle of the molten steel flow path leading to the immersion nozzle 10.
【００４１】成分Ｃ：５０ｐｐｍ、Ｓｉ：０．０１５
％、Ｍｎ：０．２５％、Ｐ：０．０２％、Ｓ：０．０１
％、Ａｌ：０．０３５％、温度１５５０℃（タンディッ
シュ内）の溶鋼２５０ｔを取鍋３からタンディッシュ１
内に２５ｔ／ｍｉｎで注入を開始すると共に、タンディ
ッシュ底部６のポーラスプラグ（アルミナ製）８から初
期気泡径１０ｍｍφのＡｒガスを５０Ｎｌ／ｍｉｎで吹
き込んだ。Component C: 50 ppm, Si: 0.015
%, Mn: 0.25%, P: 0.02%, S: 0.01
%, Al: 0.035%, temperature 1550 ° C. (within the tundish) 250 t of molten steel from ladle 3 to tundish 1
The injection was started at 25 t / min, and Ar gas with an initial bubble diameter of 10 mmφ was blown at 50 Nl / min from a porous plug (made of alumina) 8 at the bottom 6 of the tundish.
【００４２】タンディッシュ１内に溶鋼４が充満した
後、溶鋼注入量を８ｔ／ｍｉｎまで絞ると共に、鋳造を
開始した。この時、タンディッシュ出側の溶鋼中全酸素
量は注入初期から急激に低下し、鋳造を開始する２分後
には安定して全酸素量２０ｐｐｍを確保できるようにな
った。After the molten steel 4 was filled in the tundish 1, the molten steel injection rate was reduced to 8 t / min, and casting was started. At this time, the total amount of oxygen in the molten steel on the discharge side of the tundish dropped sharply from the initial stage of the injection, and a stable total oxygen amount of 20 ppm became available 2 minutes after the start of casting.
【００４３】これにより、溶鋼汚染は確実に防止でき、
圧延後の成品には表面欠陥は全く発生しなかった。Thus, the molten steel contamination can be reliably prevented,
No surface defects occurred in the product after rolling.
【００４４】[0044]
【実施例１】図２に示すタンディッシュ１を用いて操業
した例であり、該タンディッシュ１は比較例１と同一の
寸法を有するもので不活性ガス吹き込み位置が取鍋３に
設けたロングノズル５からの溶鋼注入点直下位置となさ
れている。Embodiment 1 This is an example of operation using the tundish 1 shown in FIG. 2, and the tundish 1 has the same dimensions as that of the comparative example 1, and the inert gas blowing position is long in the ladle 3. It is located just below the molten steel injection point from the nozzle 5.
【００４５】ＣａＯ：４７．５％、Ａｌ2Ｏ3：４７．５
％、ＭｇＯ：５．０％融点１４５０℃の溶融性保温剤２
を成分Ｃ：５０ｐｐｍ、Ｓｉ：０．０１５％、Ｍｎ：
０．２５％、Ｐ：０．０２％、Ｓ：０．０１％、Ａｌ：
０．０３５％、温度１５５０℃（タンディッシュ内）の
溶鋼２５０ｔを取鍋３からタンディッシュ１内に２５ｔ
／ｍｉｎで注入を開始すると同時に湯面上に添加した。CaO: 47.5%, Al 2 O 3 : 47.5
%, MgO: 5.0% Melting temperature insulator 2 with melting point of 1450 ° C
With component C: 50 ppm, Si: 0.015%, Mn:
0.25%, P: 0.02%, S: 0.01%, Al:
250 tons of molten steel at 0.035% at a temperature of 1550 ° C. (in a tundish) 25 t from ladle 3 into tundish 1
At the same time, the injection was started at a rate of / min.
【００４６】同時にタンディッシュ１の底部６のポーラ
スプラグ（アルミナ製）８から初期気泡径１０ｍｍφの
Ａｒガスを５０Ｎｌ／ｍｉｎで吹き込んだ。At the same time, Ar gas having an initial bubble diameter of 10 mmφ was blown at 50 Nl / min from a porous plug (made of alumina) 8 at the bottom 6 of the tundish 1.
【００４７】タンディッシュ１内に溶鋼が充満した後、
溶鋼注入量を８ｔ／ｍｉｎまで絞ると共に、浸漬ノズル
１０からモールド（図示省略）へ注入し鋳造を開始し
た。After the tundish 1 is filled with molten steel,
The molten steel injection amount was reduced to 8 t / min, and the molten steel was injected from a dipping nozzle 10 into a mold (not shown) to start casting.
【００４８】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急激に低下し、鋳造開始２分後には
安定して全酸素量１５ｐｐｍを確保できるようになっ
た。At this time, the total oxygen content in the molten steel on the discharge side of the tundish dropped sharply from the initial stage of injection, and a stable total oxygen content of 15 ppm became available 2 minutes after the start of casting.
【００４９】これにより、溶鋼汚染は確実に防止でき、
圧延後の成品には表面欠陥は全く発生しなかった。As a result, contamination of molten steel can be reliably prevented.
No surface defects occurred in the product after rolling.
【００５０】[0050]
【比較例２】ＭｇＯ：１００％、融点２８００℃の固体
保温剤を図１のタンディッシュ１内に予め入れ置きし
た。Comparative Example 2 A solid heat insulating agent having a MgO content of 100% and a melting point of 2800 ° C. was previously placed in the tundish 1 of FIG.
【００５１】成分Ｃ：５０ｐｐｍ、Ｓｉ：０．０１５
％、Ｍｎ：０．２５％、Ｐ：０．０２％、Ｓ：０．０１
％、Ａｌ：０．０３５％、温度１５５０℃（タンディッ
シュ内）の溶鋼２５０ｔを取鍋３からタンディッシュ１
内に２５ｔ／ｍｉｎで注入を開始し、Ａｒガス吹き込み
は実施しなかった。Component C: 50 ppm, Si: 0.015
%, Mn: 0.25%, P: 0.02%, S: 0.01
%, Al: 0.035%, temperature 1550 ° C. (within the tundish) 250 t of molten steel from ladle 3 to tundish 1
Injection was started at 25 t / min, and Ar gas injection was not performed.
【００５２】タンディッシュ１内に溶鋼４が充満した
後、溶鋼注入量を８ｔ／ｍｉｎまで絞ると共に、鋳造を
開始した。After the molten steel 4 was filled in the tundish 1, the molten steel injection rate was reduced to 8 t / min, and casting was started.
【００５３】注入開始から１８分までの間に溶鋼中全酸
素量は１４０ｐｐｍから６０ｐｐｍまで徐々に低下した
が、その後全酸素量の減少は停滞し最終到達値は６０ｐ
ｐｍであった。During the 18 minutes from the start of the injection, the total oxygen content in the molten steel gradually decreased from 140 ppm to 60 ppm, but thereafter, the decrease in the total oxygen content was stagnant and the final reached value was 60 p.
pm.
【００５４】このため、注入初期の溶鋼汚染防止機能及
びその後の介在物除去効果の向上は見られず、圧延後の
成品には表面欠陥が発生した。For this reason, the function of preventing molten steel contamination at the initial stage of injection and the effect of removing inclusions thereafter were not improved, and surface defects occurred in the product after rolling.
【００５５】[0055]
【比較例３】ＭｇＯ：１００％、融点２８００℃の固体
保温剤を図１のタンディッシュ１内に入れ置きした。Comparative Example 3 A solid warming agent having a MgO content of 100% and a melting point of 2800 ° C. was placed in the tundish 1 of FIG.
【００５６】成分Ｃ：５０ｐｐｍ、Ｓｉ：０．０１５
％、Ｍｎ：０．２５％、Ｐ：０．０２％、Ｓ：０．０１
％、Ａｌ：０．０３５％、温度１５５０℃（タンディッ
シュ内）の溶鋼２５０ｔを取鍋３からタンディッシュ１
内に２５ｔ／ｍｉｎで注入を開始すると共に、タンディ
ッシュ底部６の注入点直下から直径２５ｃｍのアルミナ
製ポーラスプラグ８により初期気泡径１０ｍｍφのもの
を５０Ｎｌ／ｍｉｎでＡｒガス９を吹き込んだ。Component C: 50 ppm, Si: 0.015
%, Mn: 0.25%, P: 0.02%, S: 0.01
%, Al: 0.035%, temperature 1550 ° C. (within the tundish) 250 t of molten steel from ladle 3 to tundish 1
The injection was started at 25 t / min, and an Ar gas 9 was blown at 50 Nl / min with an initial bubble diameter of 10 mmφ from an immediately below the injection point of the tundish bottom 6 through a 25 cm diameter alumina porous plug 8.
【００５７】タンディッシュ１内に溶鋼４が充満した
後、溶鋼注入量を８ｔ／ｍｉｎまで絞ると共に、鋳造を
開始した。After the molten steel 4 was filled in the tundish 1, the molten steel injection rate was reduced to 8 t / min, and casting was started.
【００５８】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急激に低下し鋳造を開始する２分後
には６０ｐｐｍに達したが、これ以降全酸素量は低下し
なかった。At this time, the total oxygen content in the molten steel on the discharge side of the tundish sharply decreased from the initial stage of injection, and reached 60 ppm two minutes after the start of casting. However, the total oxygen content did not decrease thereafter.
【００５９】これにより、注入初期の溶鋼汚染防止機能
は得られたものの、全酸素量の到達値は高く介在物除去
効果は向上しなかった。このため、圧延後の成品には表
面欠陥が発生した。As a result, although the function of preventing molten steel contamination at the initial stage of injection was obtained, the ultimate value of the total oxygen content was high and the effect of removing inclusions was not improved. For this reason, surface defects occurred in the product after rolling.
【００６０】[0060]
【比較例４】ＣａＯ：５０％、Ａｌ2 Ｏ3 ：５０％、融
点１４００℃の溶融性保温剤２を図１のタンディッシュ
１内に予め入れ置きした。Comparative Example 4 A fusible heat insulating agent 2 having a CaO content of 50%, an Al 2 O 3 content of 50% and a melting point of 1400 ° C. was previously placed in the tundish 1 shown in FIG.
【００６１】成分Ｃ：５０ｐｐｍ、Ｓｉ：０．０１５
％、Ｍｎ：０．２５％、Ｐ：０．０２％、Ｓ：０．０１
％、Ａｌ：０．０３５％、温度１５５０℃（タンディッ
シュ内）の溶鋼２５０ｔを取鍋３からタンディッシュ１
内に２５ｔ／ｍｉｎで注入を開始し、Ａｒガス吹き込み
は実施しなかった。Component C: 50 ppm, Si: 0.015
%, Mn: 0.25%, P: 0.02%, S: 0.01
%, Al: 0.035%, temperature 1550 ° C. (within the tundish) 250 t of molten steel from ladle 3 to tundish 1
Injection was started at 25 t / min, and Ar gas injection was not performed.
【００６２】タンディッシュ１内に溶鋼４が充満した
後、溶鋼注入量を８ｔ／ｍｉｎまで絞ると共に、鋳造を
開始した。After the molten steel 4 was filled in the tundish 1, the molten steel injection rate was reduced to 8 t / min, and casting was started.
【００６３】この時、タンディッシュ出側の溶鋼中全酸
素量は徐々に低下し、２２分程度で２０ｐｐｍに達し
た。このため、全酸素量の到達値は低く介在物除去効果
は向上したものの、全酸素量の低下速度は遅く、鋳造初
期の鋳片には圧延後表面欠陥が発生した。At this time, the total oxygen content in the molten steel on the discharge side of the tundish gradually decreased to reach 20 ppm in about 22 minutes. For this reason, although the ultimate value of the total oxygen content was low and the effect of removing inclusions was improved, the rate of decrease in the total oxygen content was slow, and the slabs at the beginning of casting had surface defects after rolling.
【００６４】[0064]
【発明の効果】以上のごとく、本発明のタンディッシュ
内溶鋼の清浄化方法によれば、大がかりな設備を必要と
せず、最も激しい鋳込初期の溶鋼汚染をすみやかに低減
し、さらにタンディッシュにおける介在物除去効果をも
向上できるため、鋳片の品質は極めて向上する。As described above, according to the method for cleaning molten steel in a tundish of the present invention, large-scale equipment is not required, the most severe molten steel contamination in the early stage of casting is promptly reduced, and furthermore, the tundish in the tundish is reduced. Since the effect of removing inclusions can also be improved, the quality of the slab is extremely improved.
【図１】比較例に用いたタンディッシュの例を示す説明
図。FIG. 1 is an explanatory diagram showing an example of a tundish used in a comparative example.
【図２】本発明実施例に用いたタンディッシュの例を示
す説明図。FIG. 2 is an explanatory view showing an example of a tundish used in the embodiment of the present invention.
【図３】るつぼ試験により評価したＡｒガス吹き込み及
び溶融性保温剤使用の効果を示す説明図。FIG. 3 is an explanatory diagram showing the effects of blowing Ar gas and using a fusible insulating agent evaluated by a crucible test.
１ タンディッシュ ２ 溶融性保温剤 ３ 取鍋 ４ 溶鋼 ５ ロングノズル ６ タンディッシュ底部 ７ 不活性ガス供給管 ８ ポーラスプラグ ９ Ａｒ気泡 １０ 浸漬ノズル DESCRIPTION OF SYMBOLS 1 Tundish 2 Melting heat insulator 3 Ladle 4 Molten steel 5 Long nozzle 6 Tundish bottom 7 Inert gas supply pipe 8 Porous plug 9 Ar bubble 10 Immersion nozzle
フロントページの続き (56)参考文献 特開 平２−55649（ＪＰ，Ａ) 特開 平５−104219（ＪＰ，Ａ) 特開 平１−180764（ＪＰ，Ａ) 特開 平６−7904（ＪＰ，Ａ) 特開 昭59−1055（ＪＰ，Ａ) 特開 昭58−68456（ＪＰ，Ａ) 特開 昭58−116962（ＪＰ，Ａ) 特開 昭62−192237（ＪＰ，Ａ) 特開 昭53−89828（ＪＰ，Ａ) 特開 昭60−261651（ＪＰ，Ａ) 特開 昭63−157745（ＪＰ，Ａ) 特開 昭58−116963（ＪＰ，Ａ) 特開 昭61−255750（ＪＰ，Ａ) 特開 昭61−82955（ＪＰ，Ａ) 特開 昭59−16659（ＪＰ，Ａ) 特開 昭61−38749（ＪＰ，Ａ) 特表 平９−501871（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B22D 11/11 B22D 11/108 B22D 11/111 B22D 11/117 Continuation of the front page (56) References JP-A-2-55649 (JP, A) JP-A-5-104219 (JP, A) JP-A-1-180644 (JP, A) JP-A-6-7904 (JP) JP-A-59-1055 (JP, A) JP-A-58-68456 (JP, A) JP-A-58-116962 (JP, A) JP-A-62-192237 (JP, A) 53-89828 (JP, A) JP-A-60-261165 (JP, A) JP-A-63-157745 (JP, A) JP-A-58-11663 (JP, A) JP-A-61-255750 (JP, A) A) JP-A-61-82955 (JP, A) JP-A-59-16659 (JP, A) JP-A-61-38749 (JP, A) Table 9-9-501871 (JP, A) (58) Survey Field (Int.Cl. 7 , DB name) B22D 11/11 B22D 11/108 B22D 11/111 B22D 11/117
Claims (1)
際、注入点直下のタンディシュ底部から不活性ガスを吹
き込むと共に、湯面を溶融性保温剤で被覆することを特
徴とするタンディシュ内溶鋼の清浄化方法。When injecting molten steel from a ladle into a tundish, an inert gas is blown from the bottom of the tundish immediately below the injection point , and the molten metal surface is covered with a melting heat insulating agent. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04059994A JP3282105B2 (en) | 1994-02-16 | 1994-02-16 | Cleaning method for molten steel in tundish |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04059994A JP3282105B2 (en) | 1994-02-16 | 1994-02-16 | Cleaning method for molten steel in tundish |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07223056A JPH07223056A (en) | 1995-08-22 |
| JP3282105B2 true JP3282105B2 (en) | 2002-05-13 |
Family
ID=12584983
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04059994A Expired - Fee Related JP3282105B2 (en) | 1994-02-16 | 1994-02-16 | Cleaning method for molten steel in tundish |
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| Country | Link |
|---|---|
| JP (1) | JP3282105B2 (en) |
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| CN107321945B (en) * | 2017-07-14 | 2019-04-30 | 山东钢铁股份有限公司 | A kind of method of purging upper nozzle for continuous casting tundish brick cup Argon removal of inclusions |
| CN107350443B (en) * | 2017-07-14 | 2019-04-30 | 山东钢铁股份有限公司 | A kind of method of continuous casting production air curtain barricade wall Argon removal of inclusions |
| CN115213393B (en) * | 2022-07-09 | 2023-07-21 | 江苏政田新材料有限公司 | Molten steel filtering device for casting anchor chain wheel |
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1994
- 1994-02-16 JP JP04059994A patent/JP3282105B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07223056A (en) | 1995-08-22 |
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