JP3911221B2 - Refractories for continuous casting - Google Patents
Refractories for continuous casting Download PDFInfo
- Publication number
- JP3911221B2 JP3911221B2 JP2002271609A JP2002271609A JP3911221B2 JP 3911221 B2 JP3911221 B2 JP 3911221B2 JP 2002271609 A JP2002271609 A JP 2002271609A JP 2002271609 A JP2002271609 A JP 2002271609A JP 3911221 B2 JP3911221 B2 JP 3911221B2
- Authority
- JP
- Japan
- Prior art keywords
- refractory
- phase
- spinel
- continuous casting
- steel
- 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
Images
Landscapes
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Compositions Of Oxide Ceramics (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、鋼の連続鋳造で使用されるロングノズル、浸漬ノズル、ストッパー、ストッパーヘッド、上ノズル等に適した連続鋳造用耐火物に関するものである。
【０００２】
【従来の技術】
これらの連続鋳造用耐火物は、溶鋼の流量制御、溶鋼の酸化防止、溶融スラグや溶融パウダーの巻き込み防止等の機能をもっている。このような機能を持つ連続鋳造用耐火物は、耐熱性、耐溶損性、耐スポール性、耐酸化性について高い性能を要求されるため、これらを構成する耐火材としてはアルミナ−黒鉛質あるいはジルコニア−黒鉛質が適用されてきた。しかしながら、アルミナ−黒鉛質耐火物を、高Ｍｎ含有鋼、高酸素含有鋼、高Ｓｉ含有鋼、Ｃａ処理鋼の鋳造に用いると、溶損が主体の損耗が生じる。一方、ジルコニア−黒鉛質耐火物は、浸漬ノズルの主にパウダーライン部と呼ばれる溶融パウダーと接触する部分に用いられているが、黒鉛の酸化やジルコニア原料の崩壊・脱落が主体の損耗が生じる。このようなノズル耐火物の損耗は、耐火物の使用寿命の低下を招くばかりでなく、製鋼操業上の支障となり、また得られる鋼材の品質にも悪影響を与える。そこで、これらの損耗を防止するために有効な連続鋳造で使用される耐火物の開発が、急務となっている。
【０００３】
このような状況に対して、特開平３−２４３２５８号公報には、ａ）Ａｌ2Ｏ3を９０質量％以上含有、ｂ）ＭｇＯを９０質量％以上含有、ｃ）ＺｒＯ2を９０質量％以上含有、のカーボンレスの各耐火物材料を、円筒状スリーブとして１種または２種以上組み合わせて内挿使用する連続鋳造用ノズルが開示されている。しかしながら、このような材料を使用した場合、次のような問題点がある。１）高Ｍｎ含有鋼、高酸素含有鋼、Ｃａ処理鋼の鋼種を鋳造する場合、耐火物中のフリーＡｌ2Ｏ3の存在で低融点物を生成するため、耐火物が溶損する。２）ＺｒＯ2やＭｇＯは高熱膨張性を有することから耐スポーリング性が低下するため、予熱あるいは使用中に割れが発生する恐れがある。
【０００４】
【発明が解決しようとする課題】
本発明は、上記の問題点に鑑みてなされたものであって、その目的とするところは、優れた耐溶損性を有するとともに、十分な耐スポーリング性及び耐酸化性を兼備している鋼の連続鋳造用耐火物を提供することにある。
【０００５】
【課題を解決するための手段】
本発明に係る連続鋳造用溶耐火物は、「鋼の連続鋳造用耐火物において、その耐火物を構成している耐火原料の鉱物相がスピネル相単独もしくは８０％以上のスピネル相とペリクレース相の混合相から構成されるとともに、スピネル結晶構造内に固溶した状態でＴｉＯ２を１〜５質量％含有し、該耐火原料とその耐火原料に対して５〜２５質量％の黒鉛を含有することによりスピネル層の厚さが数十〜百μｍの範囲であることを特徴とする連続鋳造用耐火物。」を要旨とする。
【０００６】
【発明の実施の形態】
以下に、本発明に係わる鋼の連続鋳造用耐火物を詳細に説明する。本発明の連続鋳造用耐火物は、その耐火物を構成している鉱物相がスピネル相単独もしくはスピネル相とペリクレース相の混合相からなる耐火原料から構成される。鉱物相が混合相の場合、そこに含まれるスピネル相は８０％以上であること、換言すれば、ペリクレース相が２０％以下であることが必要である。また、連続鋳造用耐火物を構成している耐火原料には、ＴｉＯ2が１〜５質量％含有している。さらに、上記の耐火原料に対して黒鉛を５〜２５質量％含有させることに特徴がある。このような構成にする理由について、以下に述べる。
【０００７】
従来のアルミナ−黒鉛質耐火物やアルミナ−シリカ−黒鉛質耐火物の溶鋼に対する溶損機構は、まず溶鋼への黒鉛の溶解反応が起る。その後、溶鋼が高酸素含有鋼、高Ｍｎ含有鋼の場合は溶鋼中の溶融状態元素であるＭｎ、ＯおよびＦｅがＭｎＯやＦｅＯ状態で稼動面に接触し、耐火物中のＡｌ2Ｏ3やＳｉＯ2と反応し、Ａｌ2Ｏ3-ＳｉＯ2-ＭｎＯ-ＦｅＯ系化合物を生成する。この化合物は溶鋼温度よりも融点が低いたいめ溶鋼流れに流失しやすいので、その結果として耐火物の溶損が生じる。またＣａ処理鋼の場合は、溶鋼中のＣａが耐火物中のＡｌ2Ｏ3やＳｉＯ2を還元し、ＣａＯを生成させる。このＣａＯが稼動面に接触するＣａＯ-Ａｌ2Ｏ3-ＳｉＯ2系化合物を生成する。この化合物は溶鋼温度よりも融点が低いため耐火物の溶損が生じる。これらの耐火物の溶融スラグに対する溶損機構については、溶鋼−溶融スラグ界面での黒鉛の溶解と溶融スラグ中のＣａＯと耐火物中のＡｌ2Ｏ3との反応によりＣａＯ-Ａｌ2Ｏ3系化合物を生成し、溶損が生じると考えられている。
【０００８】
ジルコニア−黒鉛質耐火物は、主に浸漬ノズルのパウダーライン部に使用されており、ジルコニア源としてはＣａＯ安定化ジルコニアが多用されている。この耐火物の溶損機構については、溶鋼−溶融パウダー界面での黒鉛の溶解と溶融パウダー中のＳｉＯ2やＦと耐火物中のＺｒＯ2との反応によるジルコニア骨材の崩壊と流失により、その結果耐火物の溶損が生じる。
以上のことから、鋼の連続鋳造用耐火物の溶損は、溶鋼、溶融スラグ、溶融パウダーなどの溶融物と耐火物との界面における化学反応により発生していることが分かる。
【０００９】
そこで、本発明者らは、種々の耐火物について調査研究し、特に連続鋳造用耐火物について調査研究した結果、溶損を完全に防止できる耐火物を発明するに至った。すなわち、高温では、連続鋳造用耐火物の内部においては、スピネル中のＭｇＯと黒鉛との間で次の反応が起る。尚、式における（ｓ）は固相、（ｇ）は気相を意味する。
ＭｇＯ（ｓ）＋Ｃ（ｓ）→Ｍｇ（ｇ）＋ＣＯ（ｇ） （１）
生成したＭｇガスおよびＣＯガスが耐火物と溶鋼、溶融スラグ、溶融パウダーの各界面に拡散し、そこで次の反応により、耐火物の表面に緻密なＭｇＯ層が生成する。
Ｍｇ（ｇ）＋Ｏ→ＭｇＯ（ｓ） （２）
Ｍｇ（ｇ）＋ＣＯ（ｇ）→ＭｇＯ（ｓ）＋Ｃ （３）
このＭｇＯ層は、次の反応によりＡｌ2Ｏ3と反応してスピネル（二次スピネル）を生成する。
ＭｇＯ（ｓ）+Ａｌ2Ｏ3（ｓ）→ＭｇＯ・Ａｌ2Ｏ3 （４）
【００１０】
本発明の耐火原料にはＴｉＯ2を必須成分として含有しており、式（４）の二次スピネル化反応は促進される。その理由は、以下のようである。すなわち、ＭｇＯは二価金属イオンであるＭｇ2+イオンとＯ2-イオン、Ａｌ2Ｏ3は三価金属イオンであるＡｌ3+イオンとＯ2-イオンから構成されており、ＴｉＯ2中のＴｉ4+イオンがスピネルに固溶すると、結晶構造内での電荷補償の観点から、スピネル結晶構造内に格子欠陥（空隙）が発生し、これらのイオンの拡散運動が容易になり、スピネル結晶構造を安定化させ、その結果スピネル化反応を促進し、耐火物の表面に、より緻密で厚い層を形成する。そして、この層は保護層として働き、溶鋼への耐火物中の黒鉛の溶出、溶融スラグや溶融パウダー中のＣａＯ、ＳｉＯ2やＦと耐火原料との反応を完全に防止することができる。なお、スピネル層の厚みは数十〜百μｍであるため、耐火物表面からの剥離は生じない。また、スポーリング割れに対しても悪影響を及ぼさない。
【００１１】
ここで、図１は、スピネル相からなる耐火原料にＴｉＯ2を添加した時の耐火物表面に生成したスピネル層を主体とする保護層の厚みを調査した結果である。図１から本発明に用いる耐火原料に含まれるＴｉＯ2量は、１〜５質量％の範囲が好適であることが分かる。ＴｉＯ2量が１質量％未満では、二次スピネル化反応は進まず、その結果生成したスピネル層の厚みは薄いため、耐火物の損耗を抑制する効果がない。一方、ＴｉＯ2量が５質量％を超えると、二次スピネル化反応の他にコランダムの生成反応が起るため、コランダムの溶損が起り保護層は薄くなり、その結果耐火物の溶損を防止することができない。なお本発明では、チタニアは耐火原料を構成しているスピネル結晶構造内に固溶している（チタニアが単独存在していない）ことが必要である。
【００１２】
次に、本発明の耐火原料にＴｉＯ2以外の金属酸化物を加えることについての効果について説明すると、Ｌｉ+、Ｎａ+、Ｋ+などの一価金属イオンについては、これらの金属イオンは１５００〜１６００℃の使用温度下では蒸発し固溶しない。Ｃａ2+、Ｂａ2+などの二価金属イオンは固溶せず、ＣａＯ・２Ａｌ2Ｏ3、ＢａＯ・Ａｌ2Ｏ3などの化合物を生成するためスピネル結晶構造の安定化には寄与しない。三価金属イオンであるＹ3+イオンや四価金属イオンであるＺｒ4+イオンはそのイオン半径がそれぞれ０．９３Å、０．８０ÅでＭｇ2+イオン（０．６５Å）、Ａｌ3+イオン（０．５０Å）に比べ大きく、スピネル構造内には固溶しない。Ｓｉ4+イオンやＶ5+イオンはＭｇＯやＡｌ2Ｏ3と反応し、スピネル以外の化合物を生成する。これらのことから、スピネル結晶構造の安定化と生成促進にはＴｉＯ2の添加が有効であり、他の金属酸化物は不適であることがわかる。
【００１３】
本発明の連続鋳造用耐火物において、さらに黒鉛量を５〜２５質量％含有させることが好ましいとした理由は、黒鉛量が５質量％未満であれば、耐火物の耐熱的スポーリング性が低下し、予熱中や使用中に割れるためである。一方、２５質量％を超えると、耐火物の耐酸化性が悪くなり、予熱中や使用中の組織劣化が起り溶鋼流などによる流動摩耗や、先に述べたように耐火物稼動面にスピネル緻密層が形成されても剥離しやすくなり化学的侵食が大きくなるためである。
【００１４】
また、耐火物を構成するスピネル相とペリクレース相の混合相から構成される耐火原料において、スピネル相が８０％以上の耐火原料としたのは、スピネル相が８０％未満とすると、例えばペリクレース相の存在割合が高くなることとなり、それ自身の高熱膨張性に起因して熱的スポーリング性が低下し、予熱中や使用中に割れる、またコランダム相の存在割合が高くなると溶損が大きくなる、などの理由から本発明ではスピネル相の含有量を８０％以上とした。
【００１５】
本発明の連続鋳造用耐火物は、連続鋳造用設備におけるロングノズル、浸漬ノズル、ストッパー、ストッパーヘッド、上ノズル、下ノズル等に使用される。上記の耐火物をこれらのノズルの全体に使用しても良いし、必要に応じてノズルの局部、例えば溶鋼と接する内孔部、溶融スラブと接するスラグライン部や溶融パウダーと接するパウダーライン部分等に使用される。
【００１６】
【実施例】
次に、本発明の実施例を従来例および比較例と共に挙げ、本発明を具体的に説明する。
表１に示した各耐火原料を用いて、表２に示す耐火原料Ａ〜Ｓの１９種の試料を作製した。ここで、表１の耐火原料Ａはコランダム相からなる耐火原料である。耐火原料ＢからＰ，Ｓはスピネル相単独かもしくはスピネル相とペリクレース相の混合相が主体の耐火原料で、アルミナとマグネシアの配合割合が異なる組成のものである。また、耐火原料ＣからＥ、耐火原料ＧからＩ、耐火原料ＫからＭ，Ｓはチタニア、耐火原料Ｎはカルシア、耐火原料Ｏはジルコニアをそれぞれ配合したものである。耐火原料Ｑはペリクレース相のみからなる耐火原料である。耐火原料ＲはＣａＯ安定化ジルコニア原料でバテライト相のみからなっている耐火原料である。試料は０．２mmアンダーに粒度調整したこれらの耐火原料に０．５〜０．１mmの鱗状黒鉛を１５質量％配合し、バインダーとしてフェノールレジンを添加して均一に混練し、成形した。成形体はコークス中に埋め込んで最高温度１０００℃にて還元焼成することにより得た。
【００１７】
焼成した試料を用いて溶鋼（高Ｓｉ含有鋼、Ｃａ処理鋼）、溶融スラグに対する溶損試験、スポール試験、酸化試験を実施した。溶鋼および溶融スラグに対する溶損試験は、４０×４０×１６０mmに切出した試料を高周波誘導炉内で溶解した溶鋼、溶融スラグに１６００℃×２時間浸漬し、その後の溶損量を測定することにより評価した。スポール試験は、４０×４０×１６０mmに切出した試料を高周波誘導炉内で溶解した溶銑に無予熱で１５００℃×３分浸漬した後、引き上げ３０分冷却した後の弾性率を測定し、溶銑浸漬前後の弾性率の変化率で評価した。酸化試験は５０×５０×５０mmに切出した試料を電気炉内で１４００℃×３時間加熱保持し、その後酸化層の厚みを測定することにより評価した。以下、その結果を表２に示す。
【００１８】
表２中の耐溶損性指数は従来例１の試料の溶損量を１００とした時の相対値でこの値が大きいほど溶損は小さい。また、耐スポール性指数は従来例１の試料の弾性率の変化率を１００とした時の相対値でこの値が大きいほどスポールによる耐火物組織の劣化が小さくスポールし難い。実施例１および２と比較例１および２と比較すると、ＴｉＯ2を１〜５質量％含有させることにより耐溶損性指数は向上し、比較例１および２に比べ優れた耐溶損性を有することがわかる。同様に実施例３および４と比較例３および４、実施例５および６と比較例５および６についても同じ結果であった。比較例７から１０に示すように耐火原料中を構成しているスピネル相が８０％以下の耐火原料を使用した場合には、耐溶損性と耐スポール性の両特性を満足するものはえられなかった。
【００１９】
表３は、耐火原料と配合する鱗状黒鉛量の影響を調べた結果である。比較例１１のように鱗状黒鉛量が０質量％の試料は耐スポール性に劣り、比較例１２のように鱗状黒鉛量が３０質量％の試料は耐酸化性に劣る。一方、実施例８から１０に示すように鱗状黒鉛量が５から２５質量％では、耐溶損性を維持しつつ耐スポール性と耐酸化性の両特性を満足する特性が得られている。また、これらは従来例１および２に比べ優れた耐溶損性を示すことがわかった。
【００２０】
【表１】
【表２】
【表３】
【発明の効果】
以上説明した如く、本発明に係る連続鋳造用耐火物は、耐溶損性、耐スポール性、耐酸化性に優れた特性を示す。
【図面の簡単な説明】
【図１】耐火原料中のＴｉＯ2含有量とスピネル相を主体とする表面保護層厚みの関係を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refractory material for continuous casting suitable for a long nozzle, immersion nozzle, stopper, stopper head, upper nozzle and the like used in continuous casting of steel.
[0002]
[Prior art]
These refractories for continuous casting have functions such as flow control of molten steel, oxidation prevention of molten steel, and prevention of entrainment of molten slag and molten powder. Refractories for continuous casting having such functions are required to have high performance in terms of heat resistance, erosion resistance, spall resistance, and oxidation resistance. Therefore, as a refractory material constituting them, alumina-graphite or zirconia -Graphite has been applied. However, when alumina-graphitic refractories are used for casting high Mn content steel, high oxygen content steel, high Si content steel, and Ca-treated steel, wear caused mainly by melting occurs. On the other hand, zirconia-graphitic refractories are used mainly in a portion of the immersion nozzle that comes into contact with the molten powder called a powder line portion, but wear mainly occurs due to oxidation of graphite and collapse / dropout of the zirconia raw material. Such wear of the refractory material of the nozzle not only causes a reduction in the service life of the refractory material, but also hinders steelmaking operations and adversely affects the quality of the obtained steel material. Therefore, there is an urgent need to develop a refractory material used in continuous casting that is effective for preventing these wear and tear.
[0003]
For such a situation, Japanese Patent Application Laid-Open No. 3-243258 discloses that a) Al 2 O 3 is contained in an amount of 90% by mass or more, b) MgO is contained in an amount of 90% by mass or more, and c) ZrO 2 is contained in an amount of 90% by mass or more. A continuous casting nozzle is disclosed in which each of the carbonless refractory materials is contained and used as a cylindrical sleeve in combination. However, when such a material is used, there are the following problems. 1) When casting steel types of high Mn content steel, high oxygen content steel, and Ca-treated steel, a low melting point material is generated in the presence of free Al 2 O 3 in the refractory material, so that the refractory material melts down. 2) Since ZrO 2 and MgO have high thermal expansibility, the spalling resistance is lowered, so that cracking may occur during preheating or use.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems, and the object of the present invention is steel that has both excellent spalling resistance and oxidation resistance, as well as excellent melt resistance. It is to provide a refractory for continuous casting.
[0005]
[Means for Solving the Problems]
The molten refractory material for continuous casting according to the present invention is “in a refractory material for continuous casting of steel, the mineral phase of the refractory raw material constituting the refractory is a spinel phase alone or 80% or more of a spinel phase and a periclase phase. It is composed of a mixed phase and contains 1 to 5% by mass of TiO 2 in a solid solution state in the spinel crystal structure, and 5 to 25% by mass of graphite with respect to the refractory raw material and the refractory raw material. The gist of the refractory for continuous casting is characterized in that the thickness of the spinel layer is in the range of several tens to hundreds of micrometers .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Below, the refractory for continuous casting of steel according to the present invention will be described in detail. The refractory for continuous casting of the present invention is composed of a refractory raw material in which the mineral phase constituting the refractory is a spinel phase alone or a mixed phase of a spinel phase and a periclase phase. When the mineral phase is a mixed phase, the spinel phase contained therein is 80% or more, in other words, the periclase phase needs to be 20% or less. In addition, the refractory raw material constituting the continuous casting refractories, TiO 2 is contained 1 to 5 mass%. Furthermore, it is characterized by containing 5 to 25% by mass of graphite with respect to the above refractory raw material. The reason for this configuration will be described below.
[0007]
In the conventional erosion mechanism of molten alumina-graphite refractory or alumina-silica-graphitic refractory, the melting reaction of graphite in the molten steel first occurs. Thereafter, when the molten steel is a high oxygen content steel or a high Mn content steel, Mn, O and Fe which are molten state elements in the molten steel contact the working surface in the MnO or FeO state, and Al 2 O 3 in the refractory It reacts with SiO 2 to produce an Al 2 O 3 —SiO 2 —MnO—FeO compound. Since this compound tends to be washed away in the molten steel flow having a melting point lower than the molten steel temperature, the refractory melts as a result. In the case of Ca-treated steel, Ca in the molten steel reduces Al 2 O 3 and SiO 2 in the refractory to generate CaO. This CaO produces a CaO—Al 2 O 3 —SiO 2 compound that contacts the working surface. Since this compound has a melting point lower than the molten steel temperature, refractory melts. Regarding the erosion mechanism of these refractories with respect to molten slag, the CaO-Al 2 O 3 system is obtained by melting graphite at the molten steel-molten slag interface and reacting CaO in the molten slag with Al 2 O 3 in the refractory. It is believed that a compound is formed and melt damage occurs.
[0008]
Zirconia-graphitic refractories are mainly used in the powder line portion of the immersion nozzle, and CaO-stabilized zirconia is frequently used as a zirconia source. The refractory melting mechanism is based on the dissolution of graphite at the molten steel-molten powder interface and the collapse and loss of zirconia aggregate due to the reaction between SiO 2 and F in the molten powder and ZrO 2 in the refractory. As a result, the refractory melts.
From the above, it can be seen that the melting loss of the refractories for continuous casting of steel is caused by a chemical reaction at the interface between the molten steel, molten slag, molten powder and other refractories.
[0009]
Therefore, the present inventors conducted research on various refractories, and in particular, conducted research on refractories for continuous casting. As a result, the inventors have invented a refractory that can completely prevent melting damage. That is, at the high temperature, the following reaction occurs between MgO in the spinel and graphite in the refractory for continuous casting. In the formula, (s) means a solid phase, and (g) means a gas phase.
MgO (s) + C (s) → Mg (g) + CO (g) (1)
The produced Mg gas and CO gas diffuse to each interface of the refractory and molten steel, molten slag, and molten powder, and a dense MgO layer is formed on the surface of the refractory by the following reaction.
Mg (g) + O → MgO (s) (2)
Mg (g) + CO (g) → MgO (s) + C (3)
This MgO layer reacts with Al 2 O 3 by the following reaction to generate spinel (secondary spinel).
MgO (s) + Al 2 O 3 (s) → MgO · Al 2 O 3 (4)
[0010]
The refractory raw material of the present invention contains TiO 2 as an essential component, and the secondary spinelization reaction of the formula (4) is promoted. The reason is as follows. That, MgO is a divalent metal ion Mg 2+ ions and O 2- ions, Al 2 O 3 is constituted by Al 3+ ions and O 2- ions are trivalent metal ions, in TiO 2 of When Ti 4+ ions are dissolved in spinel, from the viewpoint of charge compensation in the crystal structure, lattice defects (voids) are generated in the spinel crystal structure, and the diffusion motion of these ions becomes easy, and the spinel crystal structure As a result, the spinelization reaction is promoted, and a denser and thicker layer is formed on the surface of the refractory. This layer serves as a protective layer, and can completely prevent the elution of graphite in the refractory to the molten steel and the reaction between CaO, SiO 2 and F in the molten slag or molten powder and the refractory raw material. In addition, since the thickness of the spinel layer is several tens to one hundred μm, peeling from the surface of the refractory does not occur. Further, it does not adversely affect spalling cracks.
[0011]
Here, FIG. 1 is the result of investigating the thickness of the protective layer mainly composed of the spinel layer formed on the surface of the refractory when TiO 2 is added to the refractory raw material composed of the spinel phase. FIG. 1 shows that the amount of TiO 2 contained in the refractory raw material used in the present invention is preferably in the range of 1 to 5% by mass. If the amount of TiO 2 is less than 1% by mass, the secondary spinel reaction does not proceed, and the resulting spinel layer is thin, so there is no effect of suppressing the wear of the refractory. On the other hand, if the amount of TiO 2 exceeds 5% by mass, a corundum formation reaction occurs in addition to the secondary spinelation reaction, so that the corundum melts and the protective layer becomes thin. As a result, the refractory is melted. It cannot be prevented. In the present invention, titania needs to be dissolved in the spinel crystal structure constituting the refractory raw material (titania alone does not exist).
[0012]
Next, the effect of adding a metal oxide other than TiO 2 to the refractory raw material of the present invention will be described. For monovalent metal ions such as Li + , Na + and K + , these metal ions are 1500 to It evaporates and does not dissolve at a use temperature of 1600 ° C. Divalent metal ions such as Ca 2+ and Ba 2+ do not dissolve, and compounds such as CaO · 2Al 2 O 3 and BaO · Al 2 O 3 are produced, and thus do not contribute to stabilization of the spinel crystal structure. The Y 3+ ion, which is a trivalent metal ion, and the Zr 4+ ion, which is a tetravalent metal ion, have ion radii of 0.93 and 0.80Å, respectively, and Mg 2+ ions (0.65Å) and Al 3+ ions ( It is larger than 0.50Å) and does not dissolve in the spinel structure. Si 4+ ions and V 5+ ions react with MgO and Al 2 O 3 to produce compounds other than spinel. From these facts, it can be seen that the addition of TiO 2 is effective in stabilizing the spinel crystal structure and promoting the formation, and other metal oxides are not suitable.
[0013]
In the refractory for continuous casting of the present invention, the reason why it is preferable to further contain 5 to 25% by mass of graphite is that if the amount of graphite is less than 5% by mass, the heat resistant spalling property of the refractory is lowered. This is because it cracks during preheating and use. On the other hand, if it exceeds 25% by mass, the oxidation resistance of the refractory deteriorates, the structure deteriorates during preheating or use, and fluid wear due to the molten steel flow, etc. This is because even if a layer is formed, it is easy to peel off and chemical erosion increases.
[0014]
Moreover, in the refractory raw material composed of the mixed phase of the spinel phase and the periclase phase constituting the refractory, the refractory raw material having a spinel phase of 80% or more is assumed to be a periclase phase, for example, if the spinel phase is less than 80%. The existence ratio will be high, the thermal spalling property will decrease due to its high thermal expansion property, it will break during preheating and use, and if the existence ratio of the corundum phase becomes high, the melting loss will increase. For these reasons, the content of the spinel phase is set to 80% or more in the present invention.
[0015]
The refractories for continuous casting of the present invention are used for long nozzles, immersion nozzles, stoppers, stopper heads, upper nozzles, lower nozzles and the like in continuous casting equipment. The above-mentioned refractory may be used for the whole of these nozzles, and if necessary, the local part of the nozzle, for example, an inner hole part in contact with the molten steel, a slag line part in contact with the molten slab, a powder line part in contact with the molten powder, etc. Used for.
[0016]
【Example】
Next, examples of the present invention will be described together with conventional examples and comparative examples to specifically explain the present invention.
Using each refractory raw material shown in Table 1, 19 types of refractory raw materials A to S shown in Table 2 were prepared. Here, the refractory material A in Table 1 is a refractory material comprising a corundum phase. The refractory raw materials B to P and S are refractory raw materials mainly composed of a spinel phase alone or a mixed phase of a spinel phase and a periclase phase, and have different compositions of alumina and magnesia. Further, the refractory materials C to E, the refractory materials G to I, the refractory materials K to M, and S are titania, the refractory material N is calcia, and the refractory material O is zirconia. The refractory raw material Q is a refractory raw material consisting only of the periclase phase. The refractory raw material R is a CaO-stabilized zirconia raw material and is a refractory raw material consisting only of the vaterite phase. Samples were prepared by blending 15% by mass of 0.5 to 0.1 mm of scaly graphite with these refractory raw materials whose particle size was adjusted to under 0.2 mm, adding phenol resin as a binder, and uniformly kneading and molding. The molded body was obtained by embedding in coke and reducing firing at a maximum temperature of 1000 ° C.
[0017]
Using the fired samples, molten steel (high Si-containing steel, Ca-treated steel), a melting loss test for a molten slag, a spall test, and an oxidation test were performed. The melt loss test for molten steel and molten slag is performed by immersing a sample cut into 40 × 40 × 160 mm in molten steel and molten slag in a high-frequency induction furnace at 1600 ° C. for 2 hours, and measuring the amount of molten loss thereafter. evaluated. In the spall test, a sample cut into 40 × 40 × 160 mm was immersed in hot metal melted in a high-frequency induction furnace without preheating at 1500 ° C. for 3 minutes, then measured for elasticity after being pulled up and cooled for 30 minutes. The rate of change in elastic modulus before and after was evaluated. The oxidation test was evaluated by heating and holding a sample cut out to 50 × 50 × 50 mm in an electric furnace at 1400 ° C. for 3 hours, and then measuring the thickness of the oxide layer. The results are shown in Table 2 below.
[0018]
The erosion resistance index in Table 2 is a relative value when the erosion amount of the sample of Conventional Example 1 is 100, and the larger the value, the smaller the erosion loss. Further, the spall resistance index is a relative value when the change rate of the elastic modulus of the sample of the conventional example 1 is 100, and the larger the value, the smaller the deterioration of the refractory structure due to the spall, and the less the spall resistance is. As compared with Examples 1 and 2 and Comparative Examples 1 and 2, the inclusion of 1 to 5% by mass of TiO 2 improves the corrosion resistance index and has superior resistance to corrosion compared to Comparative Examples 1 and 2. I understand. Similarly, the same results were obtained for Examples 3 and 4 and Comparative Examples 3 and 4, and Examples 5 and 6 and Comparative Examples 5 and 6. As shown in Comparative Examples 7 to 10, when a refractory raw material having a spinel phase constituting 80% or less is used in the refractory raw material, those satisfying both the characteristics of melting resistance and spall resistance are obtained. There wasn't.
[0019]
Table 3 shows the results of examining the influence of the amount of scaly graphite blended with the refractory raw material. A sample with a scaly graphite amount of 0 mass% as in Comparative Example 11 is inferior in spall resistance, and a sample with a scaly graphite amount of 30 mass% as in Comparative Example 12 is inferior in oxidation resistance. On the other hand, as shown in Examples 8 to 10, when the amount of scaly graphite is 5 to 25% by mass, characteristics satisfying both the spall resistance and the oxidation resistance while maintaining the resistance to melting are obtained. Moreover, it turned out that these show the outstanding melt | dissolution resistance compared with the prior art examples 1 and 2.
[0020]
[Table 1]
[Table 2]
[Table 3]
【The invention's effect】
As described above, the refractory for continuous casting according to the present invention exhibits characteristics excellent in resistance to melting, spall, and oxidation.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the TiO 2 content in a refractory raw material and the thickness of a surface protective layer mainly composed of a spinel phase.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002271609A JP3911221B2 (en) | 2002-09-18 | 2002-09-18 | Refractories for continuous casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002271609A JP3911221B2 (en) | 2002-09-18 | 2002-09-18 | Refractories for continuous casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2004106014A JP2004106014A (en) | 2004-04-08 |
| JP3911221B2 true JP3911221B2 (en) | 2007-05-09 |
Family
ID=32268868
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002271609A Expired - Fee Related JP3911221B2 (en) | 2002-09-18 | 2002-09-18 | Refractories for continuous casting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3911221B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102049512B (en) * | 2011-01-18 | 2013-05-15 | 北京利尔高温材料股份有限公司 | Production method of burning-free continuous casting integral composite rod |
| JP6986958B2 (en) * | 2017-12-27 | 2021-12-22 | ＡｖａｎＳｔｒａｔｅ株式会社 | Glass substrate manufacturing equipment and glass substrate manufacturing method |
| JP2021126679A (en) * | 2020-02-14 | 2021-09-02 | 明智セラミックス株式会社 | Continuous casting nozzle |
-
2002
- 2002-09-18 JP JP2002271609A patent/JP3911221B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2004106014A (en) | 2004-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101722041B1 (en) | Refractory and nozzle for casting | |
| TWI466844B (en) | Refractory and casting nozzles | |
| US4913408A (en) | Refractory liner compositions | |
| JP3911221B2 (en) | Refractories for continuous casting | |
| JP5637630B2 (en) | Refractories for continuous casting and nozzles for continuous casting | |
| JPH09202667A (en) | Castable refractory for slide gate | |
| JPH07214259A (en) | Nozzle for continuous casting of molten steel | |
| JP3312373B2 (en) | Long nozzle for continuous casting | |
| JPH08259340A (en) | Magnesia-carbon-based castable refractory | |
| JP5920412B2 (en) | Continuous casting nozzle | |
| JPH06144939A (en) | Basic castable refractory | |
| JP2005089271A (en) | Carbon-containing refractory, its manufacturing method and its use application | |
| JP2002362969A (en) | Plate brick | |
| JP2004268143A (en) | Immersion nozzle for continuous casting of steel | |
| KR100355140B1 (en) | A method of producing and using MgO-C based refractory bricks with a coated back side for prevention of oxidation | |
| JPH0740015A (en) | Nozzle for continuous casting | |
| JPH07102436B2 (en) | Nozzle for continuous casting containing calcium zirconate | |
| JP2971824B2 (en) | High corrosion resistance refractory | |
| JPH05319902A (en) | Carbon-containing basic refractory | |
| JPH09278539A (en) | Monolithic refractory | |
| JPH11216543A (en) | Steel continuous casting nozzle | |
| JPH0283250A (en) | Production of carbon-containing calcined refractory | |
| JP2004249292A (en) | Immersion nozzle for continuously casting steel | |
| JPS61261271A (en) | Refractories for molten metal | |
| JPH06345521A (en) | Starting material for magnesian refractory and refractory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040902 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20050831 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20060117 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20060718 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20060911 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20061003 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20061201 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070123 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070126 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 3911221 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100202 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110202 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110202 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120202 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120202 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130202 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130202 Year of fee payment: 6 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130202 Year of fee payment: 6 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130202 Year of fee payment: 6 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130202 Year of fee payment: 6 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140202 Year of fee payment: 7 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| LAPS | Cancellation because of no payment of annual fees |