JPH0833960A - Insulating material for molten steel surface - Google Patents
Insulating material for molten steel surfaceInfo
- Publication number
- JPH0833960A JPH0833960A JP6191318A JP19131894A JPH0833960A JP H0833960 A JPH0833960 A JP H0833960A JP 6191318 A JP6191318 A JP 6191318A JP 19131894 A JP19131894 A JP 19131894A JP H0833960 A JPH0833960 A JP H0833960A
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- Japan
- Prior art keywords
- heat retaining
- retaining agent
- molten steel
- content
- cao
- 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.)
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- Continuous Casting (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は連続鋳造用タンディッシ
ュや取鍋などにより溶鋼を移送、又は精錬処理を行なう
際に、断熱・保温あるいは空気酸化防止を目的として溶
鋼表面を被覆する溶鋼表面保温剤に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten steel surface heat insulation for covering the molten steel surface for the purpose of heat insulation / heat retention or air oxidation prevention when the molten steel is transferred or refined by a continuous casting tundish or ladle. It is related to agents.
【０００２】[0002]
【従来の技術】連続鋳造用タンディッシュや取鍋などに
より溶鋼を移送、又は精錬処理を行なう際、保温剤を用
いて溶鋼表面を被覆し溶鋼からの熱放散と外気の浸入を
防止している。2. Description of the Related Art When molten steel is transferred or refined by a continuous casting tundish or ladle, a heat retaining agent is used to coat the surface of the molten steel to prevent heat dissipation from the molten steel and invasion of outside air. .
【０００３】従来から保温剤としては、籾殻を蒸し焼き
にした焼籾が主に用いられ、その主成分はＳｉＯ2とＣ
である。ＳｉＯ2は熱伝導率が低く保温効果に、Ｃは酸
素をＣＯガスに変えるため酸素の遮断効果に優れてい
る。このため、焼籾は保温効果及び空気遮断効果を有
し、しかも安価であることを特徴とする保温剤である。Conventionally, as the heat retaining agent, rice husks obtained by steaming rice husks have been mainly used, and their main components are SiO 2 and C.
Is. SiO 2 has a low thermal conductivity and has a heat retaining effect, and C has an excellent oxygen blocking effect because it converts oxygen into CO gas. Therefore, burned rice has a heat retaining effect and an air blocking effect, and is a cheap heat retaining agent.
【０００４】しかしながら、加工性向上の目的から鋼板
中のＣ濃度を極力低下させた、例えばＣ濃度が５０ｐｐ
ｍ以下の極低炭素鋼において、保温剤中のＣ成分が溶鋼
中にピックアップし鋼材の特性を低下させる欠点が知ら
れている。However, for the purpose of improving workability, the C concentration in the steel sheet is reduced as much as possible, for example, the C concentration is 50 pp.
It is known that in the ultra low carbon steel of m or less, the C component in the heat retaining agent is picked up in the molten steel and deteriorates the properties of the steel material.
【０００５】また、保温剤中のＳｉＯ2成分は溶鋼中の
Ａｌと反応しＡｌ2Ｏ3系の介在物を生成するため、表面
欠陥を増大させるといった問題も生じる。Further, the SiO 2 component in the heat retaining agent reacts with Al in the molten steel to form Al 2 O 3 type inclusions, which causes a problem of increasing surface defects.
【０００６】従来、焼籾のこれら欠点を解決するため、
Ｃ及びＳｉＯ2成分の少ない保温剤として、例えば特公
平３―４８１５２号公報に記載されているように、Ｍｇ
Ｏ系の保温剤が使用されている。Conventionally, in order to solve these drawbacks of rice hulls,
As a heat retaining agent containing a small amount of C and SiO 2 components, for example, as disclosed in Japanese Patent Publication No. 3-48152, Mg
An O-based heat retaining agent is used.
【０００７】また、ＭｇＯ自体は熱伝導率が高いため、
これに断熱性を付与した発泡ＭｇＯの製造方法について
も種々検討され、特公昭４８―７４８５号公報等に記載
されている。Further, since MgO itself has high thermal conductivity,
Various methods for producing foamed MgO having heat insulation properties have been investigated, and are described in Japanese Examined Patent Publication No. 48-7485.
【０００８】[0008]
【発明が解決しようとする課題】しかしながら、ＭｇＯ
を主成分とする保温剤は融点が高く、使用温度では主に
固相であるため、溶鋼表面の均一な被覆状態が得られ
ず、外気と溶鋼との反応によりＡｌ2Ｏ3系介在物を生成
する。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Since the heat-insulating agent containing as a main component has a high melting point and is mainly a solid phase at the operating temperature, a uniform coating state of the molten steel surface cannot be obtained, and Al 2 O 3 -based inclusions are generated by the reaction between the outside air and the molten steel. To generate.
【０００９】また、タンディッシュではモールド内への
溶鋼供給を制御するためにストッパーを使用している
が、ＭｇＯ系保温剤は粒子間で焼結が進み強固なスラグ
層を形成するためストッパー制御が困難となり、激しい
場合にはストッパーの折損に到る。Further, in the tundish, a stopper is used to control the supply of molten steel into the mold, but since the MgO type heat retaining agent is sintered between particles to form a strong slag layer, the stopper control can be performed. It becomes difficult, and if it is severe, the stopper will break.
【００１０】これに対し、ＭｇＯの一部をＳｉＯ2に置
き換え融点を下げる方法が考えられるが、この場合溶鋼
中ＡｌによりＳｉＯ2の還元が起こる。On the other hand, a method of replacing a part of MgO with SiO 2 to lower the melting point is conceivable. In this case, Al in molten steel causes reduction of SiO 2 .
【００１１】これらの問題を鑑み、本発明は、空気酸化
と保温剤の反応に起因する溶鋼汚染を確実に防止し、そ
の上で耐火物の損傷や溶損がなく保温機能も十分に有す
る保温剤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 reliably prevents the contamination of molten steel due to the reaction between air oxidation and a heat retaining agent, and further has a sufficient heat retaining function without damage or melting loss of refractory materials. The purpose is to provide an agent.
【００１２】[0012]
【課題を解決するための手段】本発明は、ＣａＯとＡｌ
2Ｏ3の含有率をＣａＯ／Ａｌ2Ｏ3で０．５〜１．０と
し、且つＭｇＯ含有率を５％以上３０％未満、ＳｉＯ2
含有率を１０％以下にした液相保温剤に、ＣａＯとＡｌ
2Ｏ3の含有率がＣａＯ／Ａｌ2Ｏ3で０．５未満又は２．
０を超える中空焼結体を５〜９０％含有させたことを特
徴とする溶鋼表面保温剤。The present invention is based on CaO and Al.
The content of 2 O 3 and 0.5 to 1.0 at CaO / Al 2 O 3, and the MgO content of 5% or more and less than 30%, SiO 2
Liquid phase heat insulating agent containing less than 10%, CaO and Al
2 O 3 less than in content of CaO / Al 2 O 3 0.5 or 2.
A molten steel surface heat retaining agent, characterized by containing 5 to 90% of a hollow sintered body exceeding 0.
【００１３】[0013]
【作用】溶鋼表面を被覆する保温剤として満足すべき条
件は、空気酸化と保温剤の反応に起因する溶鋼汚染を確
実に防止し、その上で耐火物の損傷や溶損がないことで
ある。[Function] A condition to be satisfied as a heat retaining agent for coating the surface of molten steel is that the contamination of molten steel caused by the reaction of air oxidation and the heat retaining agent is surely prevented, and further, there is no damage or melting loss of the refractory. .
【００１４】発明者等はこれら基本条件を満足すべく保
温剤の検討を進めてきた結果、空気酸化を抑制するため
には保温剤の液相化が、保温剤と溶鋼の反応を防止する
ためには低ＳｉＯ2化が有効であることを見いだした。
すなわち、保温剤の融点を下げ液相を生成することは溶
鋼表面の被覆状態を均一化し、保温剤自体の空気酸化防
止能を高める。[0014] As a result of the inventors' investigations on the heat retaining agent so as to satisfy these basic conditions, as a result, in order to suppress the air oxidation, the heat retaining agent is made into a liquid phase to prevent the reaction between the heat retaining agent and the molten steel. It was found that lowering SiO 2 is effective for this.
That is, lowering the melting point of the heat retaining agent to generate a liquid phase makes the coating state of the molten steel surface uniform and enhances the air oxidation preventing ability of the heat retaining agent itself.
【００１５】また、保温剤中のＳｉＯ2は（１）式によ
り溶鋼中のＡｌと反応するため、保温剤の低ＳｉＯ2化
はＡｌ2Ｏ3系介在物の生成防止に効果を有する。Further, since SiO 2 in the heat retaining agent reacts with Al in the molten steel according to the formula (1), lowering the SiO 2 content of the heat retaining agent is effective in preventing the formation of Al 2 O 3 type inclusions.
【００１６】[0016]
【化１】 ３ＳｉＯ2＋４Ａｌ＝２Ａｌ2Ｏ3＋３Ｓｉ （１）Embedded image 3SiO 2 +4 Al = 2Al 2 O 3 +3 Si (1)
【００１７】これらの点を考慮して、液相化と低ＳｉＯ
2化を満足する保温剤について検討を重ねた結果、Ｃａ
ＯとＡｌ2Ｏ3の含有率をＣａＯ／Ａｌ2Ｏ3で０．５〜
１．０の範囲とし、ＳｉＯ2含有率を１０％以下にする
ことが最適であることを見いだした。In consideration of these points, liquid phase formation and low SiO 2
As a result of repeated studies on heat insulation agents that satisfy the requirement of 2
0.5 The content of O and Al 2 O 3 with CaO / Al 2 O 3
It was found that the optimum range is 1.0 and the SiO 2 content is 10% or less.
【００１８】なお、ＣａＯ／Ａｌ2Ｏ3を０．５〜１．０
の範囲にしたのは、図１に示すように保温剤の軟化点が
タンディッシュにおける溶鋼温度（１５５０℃）以下と
なり、液相化するためである。CaO / Al 2 O 3 is added in an amount of 0.5 to 1.0.
The reason why the range is set is that the softening point of the heat retaining agent becomes the liquid steel temperature (1550 ° C.) or lower in the tundish and becomes a liquid phase as shown in FIG.
【００１９】また、ＳｉＯ2含有率を１０％以下にした
のは、図２に示すように保温剤中ＳｉＯ2と溶鋼中Ａｌ
の反応速度が急激に遅くなり工業的に問題となるレベル
以下に反応を抑えることができるためである。As shown in FIG. 2, the SiO 2 content is set to 10% or less because the SiO 2 in the heat retaining agent and the Al in the molten steel are
This is because the reaction rate of (1) is drastically slowed down and the reaction can be suppressed below a level that is industrially problematic.
【００２０】しかし、本成分の保温剤をタンディッシュ
に適用した場合、成分によってはストッパー耐火物の溶
損が急激に進行し、長時間の使用に耐えないことが分か
った。However, when the heat retaining agent of this component was applied to a tundish, it was found that depending on the component, the erosion of the stopper refractory material rapidly progressed and it could not withstand long-term use.
【００２１】そこで、本発明者らは、前述した成分の保
温剤でＣａＯ／Ａｌ2Ｏ3を変更すると共に、ＭｇＯを添
加し、保温剤が固相化しない範囲で融点を上げ、ストッ
パー耐火物の溶損防止を検討した。その結果を図３に示
す。Therefore, the inventors of the present invention changed the CaO / Al 2 O 3 with the heat retaining agent of the above-mentioned components, and added MgO to raise the melting point in the range where the heat retaining agent did not solidify, and the stopper refractory The prevention of melting damage was investigated. The result is shown in FIG.
【００２２】保温剤の成分がＣａＯ／Ａｌ2Ｏ3で１．０
より大きい範囲では溶損速度が速く、さらにＭｇＯの添
加はかえって溶損速度を速める。The component of the heat retaining agent is CaO / Al 2 O 3 and is 1.0
In the larger range, the dissolution rate is high, and addition of MgO rather accelerates the dissolution rate.
【００２３】これに対し、保温剤の成分がＣａＯ／Ａｌ
2Ｏ3で１．０以下の範囲では、ＭｇＯを５％以上添加す
ることにより溶損速度が急激に低下し、工業的に使用可
能（溶損速度で０．１ｍｍ／ｍｉｎ以下）なまでに溶損
を抑えることができる。On the other hand, the component of the heat retaining agent is CaO / Al.
When the content of 2 O 3 is 1.0 or less, the melt loss rate sharply decreases by adding MgO in an amount of 5% or more, and it becomes industrially usable (at a melt loss rate of 0.1 mm / min or less). Melt loss can be suppressed.
【００２４】しかし、溶鋼温度（１５５０℃）でＭｇＯ
含有率が３０％以上になると、保温剤中の液相は極めて
少なくなる。However, at the molten steel temperature (1550 ° C.), MgO
When the content is 30% or more, the liquid phase in the heat retaining agent becomes extremely small.
【００２５】その結果、保温剤は溶鋼表面を均一に覆わ
ず、外気の侵入によりＡｌ2Ｏ3系の介在物を生成する。
したがって、保温剤中への最適ＭｇＯ含有率は５％以上
３０％未満である。As a result, the heat retaining agent does not uniformly cover the surface of the molten steel, and Al 2 O 3 type inclusions are generated by the invasion of the outside air.
Therefore, the optimum MgO content in the heat retaining agent is 5% or more and less than 30%.
【００２６】以上に示した成分の保温剤を使用すること
により空気酸化と保温剤の反応に起因する溶鋼汚染及び
耐火物の溶損を確実に抑制できるが、保温剤の液相化に
伴い保温機能が低下する。By using the heat retaining agent having the above-mentioned components, it is possible to surely suppress the molten steel contamination and the melting loss of the refractory due to the reaction between the air oxidation and the heat retaining agent. Function deteriorates.
【００２７】このため、上記成分の液相保温剤を使用す
る場合、転炉やＲＨの処理温度を高めタンディッシュ内
の温度低下を補償する必要がある。For this reason, when the liquid phase heat retaining agent of the above components is used, it is necessary to raise the processing temperature of the converter and RH to compensate for the temperature drop in the tundish.
【００２８】しかし、処理温度を高めると転炉、ＲＨ及
び鍋の耐火物寿命が短くなることが予想される。However, it is expected that the refractory life of the converter, RH and pot will be shortened if the treatment temperature is raised.
【００２９】そこで、本発明者らは溶鋼温度低下の問題
をも同時に解消できる保温剤の研究を重ねた結果、前述
した成分の液相保温剤に中空の焼結体を含有させること
が有効であることを見いだした。Therefore, as a result of repeated studies of the heat retaining agent which can solve the problem of the molten steel temperature lowering at the same time, it is effective that the liquid phase heat retaining agent of the above-mentioned component contains a hollow sintered body. I found something.
【００３０】前述の液相保温剤に中空の焼結体を含有さ
せた場合、図４に示したように液相保温剤は液相化し下
部へ、見掛け比重が小さい中空の焼結体１は液相２の上
部に集まる。When the above-mentioned liquid phase heat retaining agent contains a hollow sintered body, as shown in FIG. 4, the liquid phase heat retaining agent is liquid-phased to the lower side, and the hollow sintered body 1 having a small apparent specific gravity is Collect at the top of liquid phase 2.
【００３１】その結果、タンディッシュ５内の保温剤４
は２層構造となり、溶鋼３と接する下部の液相２は溶鋼
３表面を均一に被覆し空気酸化防止機能を高め、さらに
上部の中空焼結体１は保温効果を高める。As a result, the heat retaining agent 4 in the tundish 5
Has a two-layer structure, the lower liquid phase 2 in contact with the molten steel 3 evenly covers the surface of the molten steel 3 to enhance the air oxidation preventing function, and the upper hollow sintered body 1 enhances the heat retaining effect.
【００３２】ここで、中空の焼結体が液相化すれば保温
機能を高める効果を失うため、鋳造温度では固相状態を
維持でき、且つ液相保温剤と反応して溶融しないことが
重要である。Here, since the effect of enhancing the heat retaining function is lost if the hollow sintered body is in the liquid phase, it is important that the solid state can be maintained at the casting temperature and that it does not melt by reacting with the liquid phase heat retaining agent. Is.
【００３３】そのためには、中空焼結体の軟化点を鋳造
温度より高くし、さらに液相保温剤と主成分を同じにす
ることが有効である。For that purpose, it is effective to make the softening point of the hollow sintered body higher than the casting temperature and to make the liquid phase heat insulating agent and the main component the same.
【００３４】よって、中空焼結体の主成分をＣａＯ、Ａ
ｌ2Ｏ3とし、液相保温剤とは逆に、図１よりＣａＯ／Ａ
ｌ2Ｏ3を０．５未満又は２．０超にすれば良い。また、
中空焼結体の含有率が５％未満では中空焼結体が保温剤
の上部全体を覆わないため保温機能は向上せず、９０％
を超えると反対に液相保温剤の量が少なくなり液相が湯
面全体を被覆しないため空気遮断能が低下する。したが
って、最適な中空焼結体の含有率は５〜９０％である。Therefore, the main components of the hollow sintered body are CaO and A.
1 2 O 3 and CaO / A as shown in FIG.
L 2 O 3 may be less than 0.5 or more than 2.0. Also,
If the content of the hollow sintered body is less than 5%, the hollow sintered body does not cover the entire upper part of the heat retaining agent, so the heat retaining function does not improve, and 90%
On the contrary, when the amount exceeds the above, the amount of the liquid phase heat retaining agent becomes small and the liquid phase does not cover the entire molten metal surface, so that the air blocking ability decreases. Therefore, the optimum hollow sintered body content is 5 to 90%.
【００３５】保温剤の基本的成分は以上に述べた通りで
あるが、本発明品の機能を低下させない範囲で、液相保
温剤にはＣａＣｌ2，ＣａＦ2等、中空焼結体にはＭｇＯ
等の他成分の添加も可能である。The basic components of the heat retaining agent are as described above, but CaCl 2 and CaF 2 are used as the liquid phase heat retaining agent and MgO is used as the hollow sintered body as long as the function of the product of the present invention is not deteriorated.
It is also possible to add other components such as.
【００３６】以上に示したように、本発明の保温剤を用
いることにより空気酸化と保温剤の反応に起因する溶鋼
汚染を確実に防止でき、その上で耐火物の損傷や溶損が
なく、十分な保温機能を有する溶鋼保温剤を提供でき
る。As shown above, by using the heat retaining agent of the present invention, it is possible to reliably prevent the contamination of molten steel due to the reaction of air oxidation and the heat retaining agent, and furthermore, there is no damage or melting loss of the refractory, A molten steel heat retaining agent having a sufficient heat retaining function can be provided.
【００３７】[0037]
【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。EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples.
【００３８】第１表に示す成分の保温剤４００ｋｇを容
量６０ｔｏｎのタンディッシュに添加し、低炭アルミキ
ルド鋼を４００分間鋳造した。400 kg of a heat retaining agent having the components shown in Table 1 was added to a tundish having a capacity of 60 tons, and low carbon aluminum killed steel was cast for 400 minutes.
【００３９】本発明の実施例及び比較例とも、鋳造寸法
は厚み２４５ｍｍ×幅１５００ｍｍで、８５００ｍｍ長
さに切断して１コイル単位とした。In both the examples and comparative examples of the present invention, the casting dimensions were 245 mm in thickness and 1500 mm in width, and cut into lengths of 8500 mm to make one coil unit.
【００４０】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。This slab was hot-rolled and cold-rolled by a conventional method to finally obtain a cold-rolled steel sheet having a thickness of 0.7 mm and a width of 1500 mm.
【００４１】保温剤の空気遮断効果及び反応防止効果は
タンディッシュ入側と出側の全酸素量の上昇量及び冷延
鋼板に発生した表面欠陥の発生個数により評価した。The air blocking effect and reaction preventing effect of the heat retaining agent were evaluated by the amount of increase in the total oxygen content on the tundish inlet side and the outlet side and the number of surface defects generated on the cold rolled steel sheet.
【００４２】また、耐火物の溶損については使用後スト
ッパーの溶損量を測定し、鋳造時間から溶損速度を算出
した。なお、鋳造において使用したストッパー耐火物の
材質はロウセキであった。Regarding the melting loss of the refractory material, the amount of the melting loss of the stopper after use was measured, and the melting rate was calculated from the casting time. The material of the stopper refractory used in the casting was wax.
【００４３】保温機能については、タンディッシュ入側
と出側の温度低下により評価した。The heat-retaining function was evaluated by the temperature decrease on the inlet side and the outlet side of the tundish.
【００４４】ここで、中空保温剤を添加しない液相保温
剤では、タンディッシュ入側・出側間で通常２５℃程度
の温度低下が生じていた。Here, in the liquid phase heat retaining agent to which the hollow heat retaining agent was not added, the temperature usually dropped by about 25 ° C. between the tundish inlet side and the tundish inlet side.
【００４５】[0045]
【表１】 [Table 1]
【００４６】第２表に示す如く、実施例ではＣａＯとＡ
ｌ2Ｏ3の含有率をＣａＯ／Ａｌ2Ｏ3で０．５〜１．０と
し、且つＭｇＯ含有率を５％以上３０％未満、ＳｉＯ2
含有率を１０％以下にした液相保温剤に、ＣａＯとＡｌ
2Ｏ3の含有率がＣａＯ／Ａｌ2Ｏ3で０．５未満又は２．
０を超える中空焼結体を５〜９０％含有させた保温剤を
使用したことで、空気酸化と保温剤の反応に起因する溶
鋼汚染を防止でき、タンディッシュ入側・出側間の溶鋼
全酸素量の上昇及び表面欠陥の発生は全くなかった。As shown in Table 2, in the examples, CaO and A were used.
The content of l 2 O 3 is CaO / Al 2 O 3 of 0.5 to 1.0, and the content of MgO is 5% or more and less than 30%, SiO 2
Liquid phase heat insulating agent containing less than 10%, CaO and Al
2 O 3 less than in content of CaO / Al 2 O 3 0.5 or 2.
By using the heat retaining agent containing 5 to 90% of the hollow sintered body exceeding 0, it is possible to prevent the molten steel contamination caused by the reaction of the air oxidizing agent and the heat retaining agent, so that the molten steel between the tundish inlet side and the outlet side can be completely prevented. There was no increase in oxygen content and generation of surface defects.
【００４７】また、ストッパー耐火物の溶損速度も低下
するため、連々鋳回数が増加する場合にも十分使用に耐
えうることが確認された。さらに、タンディッシュ入側
・出側間の温度低下も抑制された。Further, it was confirmed that the melting rate of the stopper refractory material was also lowered, so that the stopper refractory material could be sufficiently used even when the number of castings was continuously increased. Furthermore, the temperature drop between the tundish inlet side and outlet side was also suppressed.
【００４８】[0048]
【表２】 [Table 2]
【００４９】これに対し、比較例１は液相保温剤中のＣ
ａＯ／Ａｌ2Ｏ3が１．０を超え、さらに中空焼結体のＣ
ａＯ／Ａｌ2Ｏ3が０．５〜２．０の範囲にあったため、
比較例２は液相保温剤中のＭｇＯ含有率が５％未満で、
中空焼結体のＣａＯ／Ａｌ2Ｏ3が０．５〜２．０の範囲
にあったため、共にストッパー耐火物の溶損及びタンデ
ィッシュ温度の低下を抑制することができなかった。On the other hand, in Comparative Example 1, C in the liquid phase heat retaining agent was used.
aO / Al 2 O 3 exceeds 1.0, and C of the hollow sintered body
Since aO / Al 2 O 3 was in the range of 0.5 to 2.0,
Comparative Example 2 has a MgO content of less than 5% in the liquid phase heat retaining agent,
Since CaO / Al 2 O 3 of the hollow sintered body was in the range of 0.5 to 2.0, it was not possible to suppress the melting loss of the stopper refractory and the decrease of the tundish temperature.
【００５０】比較例３は液相保温剤中のＣａＯ／Ａｌ2
Ｏ3が０．５未満であったため、比較例４は液相保温剤
中のＭｇＯ含有率が３０％を超えたため、保温剤が固相
となり十分な断気効果が得られず、タンディッシュ入側
・出側間の溶鋼全酸素量が上昇し表面欠陥が発生した。Comparative Example 3 is CaO / Al 2 in the liquid phase heat retaining agent.
Since O 3 was less than 0.5, the MgO content in the liquid phase heat retaining agent exceeded 30% in Comparative Example 4, so that the heat retaining agent became a solid phase and a sufficient deaeration effect was not obtained. The total amount of molten steel oxygen between the side and outlet side increased and surface defects occurred.
【００５１】また、比較例５は液相保温剤中のＳｉＯ2
含有率が１０％を超えたため、溶鋼中Ａｌとの反応によ
りＡｌ2Ｏ3系介在物が生成した。In Comparative Example 5, SiO 2 in the liquid phase heat retaining agent was used.
Since the content exceeds 10%, Al 2 O 3 -based inclusions are generated by the reaction with Al in the molten steel.
【００５２】その結果、タンディッシュ入側・出側間の
溶鋼全酸素量が増大し、表面欠陥が発生した。As a result, the total amount of molten steel oxygen between the tundish inlet side and the tundish side increased, and surface defects occurred.
【００５３】比較例６は中空焼結体の含有率が９０％を
超えたため、反対に液相保温剤が湯面全体を被覆できな
くなり十分な断気効果が得られず、タンディッシュ入側
・出側間の溶鋼全酸素量が上昇し表面欠陥が発生した。In Comparative Example 6, since the content of the hollow sintered body exceeded 90%, on the contrary, the liquid phase heat retaining agent could not cover the entire surface of the molten metal and a sufficient deaeration effect could not be obtained. The total oxygen content of molten steel between the outlet side increased and surface defects occurred.
【００５４】さらに、比較例７は中空焼結体の含有率が
５％未満であったため、保温剤の上部全体を覆わず保温
機能は向上しなかった。Furthermore, in Comparative Example 7, the content of the hollow sintered body was less than 5%, so the whole upper part of the heat retaining agent was not covered and the heat retaining function was not improved.
【００５５】[0055]
【発明の効果】以上に説明したように、本発明の溶鋼保
温剤によれば溶鋼の汚染は全くなく、鋳片品質は極めて
向上する。また、耐火物の損傷や溶損もなく、且つ保温
機能も極めて高いため、操業面でも有効な保温剤を提供
できる。As described above, according to the molten steel heat retaining agent of the present invention, the molten steel is not contaminated at all, and the slab quality is extremely improved. Further, since the refractory is not damaged or melted and the heat retaining function is extremely high, it is possible to provide an effective heat retaining agent in terms of operation.
【図１】保温剤のＣａＯ／Ａｌ2Ｏ3と融点の関係を示す
図。FIG. 1 is a diagram showing a relationship between CaO / Al 2 O 3 of a heat retaining agent and a melting point.
【図２】保温剤中のＳｉＯ2含有率と反応速度の関係を
示す図。FIG. 2 is a diagram showing a relationship between a SiO 2 content rate in a heat retaining agent and a reaction rate.
【図３】保温剤中のＭｇＯ添加量と溶損速度の関係を示
す図。FIG. 3 is a graph showing the relationship between the amount of MgO added to the heat retaining agent and the dissolution rate.
【図４】本発明保温剤の使用時の状態を説明する図。FIG. 4 is a diagram illustrating a state of using the heat retaining agent of the present invention.
１ 中空焼結体 ２ 液相 ３ 溶鋼 ４ 保温剤 ５ タンディッシュ 1 Hollow Sintered Body 2 Liquid Phase 3 Molten Steel 4 Heat Retaining Agent 5 Tundish
Claims (1)
ｌ2Ｏ3で０．５〜１．０とし、且つＭｇＯ含有率を５％
以上３０％未満、ＳｉＯ2含有率を１０％以下にした液
相保温剤に、ＣａＯとＡｌ2Ｏ3の含有率がＣａＯ／Ａｌ
2Ｏ3で０．５未満又は２．０を超える中空焼結体を５〜
９０％含有させたことを特徴とする溶鋼表面保温剤。1. The content of CaO and Al 2 O 3 is CaO / A.
L 2 O 3 to 0.5 to 1.0, and MgO content 5%
The content of CaO and Al 2 O 3 is CaO / Al in a liquid phase heat insulating material having a SiO 2 content of 10% or less and less than 30%.
2 O 3 contains less than 0.5 or more than 2.0 hollow sintered body 5
A molten steel surface heat retaining agent containing 90%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6191318A JPH0833960A (en) | 1994-07-22 | 1994-07-22 | Insulating material for molten steel surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6191318A JPH0833960A (en) | 1994-07-22 | 1994-07-22 | Insulating material for molten steel surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0833960A true JPH0833960A (en) | 1996-02-06 |
Family
ID=16272566
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6191318A Withdrawn JPH0833960A (en) | 1994-07-22 | 1994-07-22 | Insulating material for molten steel surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0833960A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007260741A (en) * | 2006-03-29 | 2007-10-11 | Jfe Steel Kk | Method of starting continuous casting of molten steel |
-
1994
- 1994-07-22 JP JP6191318A patent/JPH0833960A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007260741A (en) * | 2006-03-29 | 2007-10-11 | Jfe Steel Kk | Method of starting continuous casting of molten steel |
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