JPS6348828B2 - - Google Patents

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Publication number
JPS6348828B2
JPS6348828B2 JP55079871A JP7987180A JPS6348828B2 JP S6348828 B2 JPS6348828 B2 JP S6348828B2 JP 55079871 A JP55079871 A JP 55079871A JP 7987180 A JP7987180 A JP 7987180A JP S6348828 B2 JPS6348828 B2 JP S6348828B2
Authority
JP
Japan
Prior art keywords
carbon
nozzle
boron carbide
resistance
present
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
Application number
JP55079871A
Other languages
Japanese (ja)
Other versions
JPS577868A (en
Inventor
Hiroki Yanagi
Mikio Sakaguchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harima Refractories Co Ltd
Original Assignee
Harima Refractories Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Harima Refractories Co Ltd filed Critical Harima Refractories Co Ltd
Priority to JP7987180A priority Critical patent/JPS577868A/en
Publication of JPS577868A publication Critical patent/JPS577868A/en
Publication of JPS6348828B2 publication Critical patent/JPS6348828B2/ja
Granted legal-status Critical Current

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  • Compositions Of Oxide Ceramics (AREA)
  • Ceramic Products (AREA)
  • Continuous Casting (AREA)

Description

【発明の詳細な説明】[Detailed description of the invention]

本発明は、耐食性、熱間強度および耐スポーリ
ング性にすぐれたAl2O3−SiO2−C系連続鋳造用
耐火物の製造方法に関するものである。 鋼の連続鋳造において、溶鋼を取鍋からタンデ
ツシユ、あるいはタンデツシユからモールドへ移
送させるノズルは、溶鋼の酸化や乱流の防止、溶
鋼注出量の調整などの役割をもち、その材質の良
否は鋼製品の品質に大きく影響するため、連続鋳
造設備の中でも特に重要な部材である。このノズ
ルは、溶損による口径拡大が進むと溶鋼注出量を
一定に保つことができなくなると共に、溶鋼流の
乱れによつてタンデツシユ内のスラグ、あるいは
モールド内に添加されているパウダーを溶鋼中に
捲き込み、鋼製品の品質低下を招く。また、ノズ
ルは容器に内張りされた耐火物のように外殻に保
持されていなく、しかも長尺形状であるため熱
的、機械的応力によつて破損を招きやすい。 以上のことから、連続鋳造用ノズルに要求され
る耐食性、熱間強度および耐スポーリング性は、
他の耐火物に比べてきわめて苛酷である。 このため、従来から種々の材質が提案されてお
り、その1種としてAl2O3−SiC−C系があるが、
この材質は耐食性および耐スポーリング性にすぐ
れている反面、炭素を含有しているため使用中の
高温によつて酸化されるという欠点があつた。 本発明者らはAl2O3−SiO2−C系材質のこの欠
点を解決すべく、酸化防止剤として周知の炭化硼
素を添加したところ、酸化防止効果は得られたも
のの、製造工程における焼成中に炭化硼素はその
一部が分解して焼結剤として作用し、得られたノ
ズルは焼結過度となつて耐スポーリング性のもの
となつた。また、これが使用中には炭化硼素が漸
次分解し、他の成分と反応して低融点物質を生成
し、ノズルの熱間強度の低下を促すなどの問題が
あり、本質的な解系策にはならなかつた。 本発明は上記従来の問題を解決するもので、重
量割合でアルミナ40〜65%、シリカ1〜30%、炭
素10〜45%、炭化硼素0.05〜2%(外掛)とし、
かつ、前記炭素のうち3〜25%(配合物全体に占
める割合0.3〜11.3%)が平均粒径5μ以下のカー
ボンブラツクである配合物を混練、成形後、還元
焼成することを特徴とする連続鋳造用ノズルの製
造方法である。 すなわち、本発明は配合物中の炭素の粒度調整
を行なうことによつて炭化硼素添加にともなう耐
スポーリング性および熱間強度の低下を阻止し、
炭化硼素のもつ酸化防止作用を効果的に発揮させ
るものである。 炭素の粒度調整によつて上記の効果が生じるの
は、つぎのような理由によるものと思考される。 添加された炭化硼素は、焼成中の低酸素分圧化
においてもその一部が分解してB2O3となり、こ
れがさらに他の成分と反応して硼素系低融点物質
を生成し、ノズルは焼結が著しく促進されて耐ス
ポーリング性に劣る組織となるが、本発明では添
加した超微粒子炭素であるカーボンブラツクがそ
の被吸着能により炭化硼素の表面をコーテイング
せしめ、よつて耐スポーリング性劣化の原因とな
る焼成中の炭化硼素の分解を阻止する。また、た
とえ焼成中に低融点物質が生成したとしても、カ
ーボンブラツク等の炭素が超微粒子であるがゆえ
に分散性が良く、低融点物質中に分散して、低融
点物質を不連続にし、その焼成体の弾性率の上昇
を防ぐ。 さらに、ノズルの使用中においては、炭化硼素
は前記と同様に低融点物質を生成し、これが粒子
間の液相となつてノズルの強度劣化を招くが、本
発明では超微粒子の炭素が低融点物質内に分散し
ているため、液相の粘性を上昇させることによつ
て強度劣化を防止する。 つぎに、本発明に用いる配合原料の具体例、お
よび限定理由について述べる。なお、以下に示す
%は、いずれも重量割合によるものである。 アルミナは電融品、焼結品のいずれでもよく、
その割合は40〜65%である。40%以下ではアルミ
ナの耐食性が発現できず、また65%以上ではノズ
ルの耐スポーリング性が劣る。 シリカは溶融シリカ、無定形シリカなどの非晶
質のものから選択使用し、割合は1〜30%で、さ
らに好ましいのは5〜25%である。1%以下では
シリカのもつ低膨張性が十分発現されないために
ノズルの耐スポーリング性が劣り、30%以上では
低融点物質を多量に生成して耐食性が低下する。 炭化硼素は外掛で0.05〜2%、さらに好ましく
は外掛で0.1〜1.5%である。0.05%以下では耐酸
化性作用が十分でなく、2%以上では熱間強度に
劣るとともに、添加量が多いことから経済面でも
好ましくない。 炭素は結晶質、非結晶質を問わず使用でき、例
えば鱗状黒鉛、土状黒鉛、電極屑、コークス、ピ
ツチ、カーボンブラツクなどであり、その割合は
10〜45%とする。10%以下ではノズルの耐食性、
耐スポーリング性が不十分で、45%以上では耐酸
化性の面から好ましくない。 そして、本発明では前記炭素のうち3〜50%を
平均粒径5μ以下の超微粒子炭素のカーボンブラ
ツクとする。3%以下では耐スポーリング性、熱
間強度が従来のものと何んら変りなく、50%以上
では気孔率が上昇し、耐食性の面から好ましくな
い。なお、前記カーボンブラツクの割合は炭素原
料全体を100%とした場合のもので、これを他の
原料であるアルミナ、シリカ、炭化硼素を含めた
配合全体に対する割合に換算すると0.3〜22.5%
となる。 また、本発明の効果を損なわない程度であれ
ば、以上の原料の他にムライト、炭化珪素、窒化
珪素、窒化硼素、ジルコニア、金属粉、セラミツ
クフアイバーなどを適当量添加してもよい。 本発明は以上の配合物に結合剤として例えばタ
ールピツチ、クレオソート油、CMC、PVA、パ
ルプ廃液、フエノール樹脂、フラン樹脂、ポリエ
ステル樹脂、アクリロニトリル樹脂など添加し、
常温混練、必要によつては加熱混練し、所望の形
状にラバープレス成形した後、1000〜1100℃で還
元焼成して得られる。 つぎに本発明の実施例とその比較例を示す。 各例はいずれも結合剤としてフエノール樹脂を
外掛で5%添加して混練し、ノズル形状にラバー
プレス(加圧力1000Kg/cm2)成形した後、1000℃
×3時間で還元焼成したものである。 テーブル試験はノズルから切出した試験片によ
つて行なつた。見掛比重、嵩比重および気孔率は
JIS−R2205にもとずいて行なつた。曲げ強さは
幅40×厚さ20×長さ150mmの試験片を100mmのスパ
ン上に置き、各温度下で測定した。弾性率は幅30
×厚さ30×長さ150mmの試験片を超音波方式にて
測定した。酸化減量は、30×30×30mmの試験片を
各温度の電気炉中で2時間加熱し、加熱前と加熱
後との重量差を酸化減量とした。
The present invention relates to a method for producing an Al2O3 - SiO2 - C continuous casting refractory having excellent corrosion resistance, hot strength, and spalling resistance. In continuous steel casting, the nozzle that transfers molten steel from the ladle to the tundish or from the tundish to the mold has the role of preventing molten steel from oxidation and turbulence, and adjusting the amount of molten steel poured out.The quality of the material depends on the quality of the steel. It is a particularly important component in continuous casting equipment, as it has a major impact on product quality. As the diameter of this nozzle continues to expand due to melting damage, it becomes impossible to keep the amount of molten steel poured out constant, and the turbulence of the molten steel flow causes slag in the tundish or powder added in the mold to flow into the molten steel. This leads to deterioration in the quality of steel products. Further, the nozzle is not held in an outer shell like the refractory lining the container, and is elongated, so it is susceptible to damage due to thermal and mechanical stress. From the above, the corrosion resistance, hot strength and spalling resistance required for continuous casting nozzles are as follows:
It is extremely harsh compared to other refractories. For this reason, various materials have been proposed in the past, one of which is Al 2 O 3 -SiC-C system.
Although this material has excellent corrosion resistance and spalling resistance, it has the disadvantage that it is oxidized by high temperatures during use because it contains carbon. In order to solve this drawback of Al 2 O 3 -SiO 2 -C-based materials, the present inventors added boron carbide, a well-known antioxidant, and although an antioxidant effect was obtained, A portion of the boron carbide decomposed and acted as a sintering agent, and the resulting nozzle became excessively sintered, making it resistant to spalling. Additionally, during use, boron carbide gradually decomposes and reacts with other components to produce low melting point substances, which promotes a decrease in the hot strength of the nozzle. I couldn't stop. The present invention solves the above-mentioned conventional problems, and the weight ratio is 40 to 65% alumina, 1 to 30% silica, 10 to 45% carbon, and 0.05 to 2% boron carbide (outer weight).
A continuous method characterized in that a compound in which 3 to 25% of the carbon (0.3 to 11.3% of the total compound) is carbon black with an average particle size of 5 μ or less is kneaded, molded, and then reduced and fired. This is a method for manufacturing a casting nozzle. That is, the present invention prevents a decrease in spalling resistance and hot strength due to the addition of boron carbide by adjusting the particle size of carbon in the compound,
This effectively exhibits the antioxidant effect of boron carbide. The reason why the above effects are produced by adjusting the particle size of carbon is considered to be due to the following reasons. Part of the added boron carbide decomposes during the low oxygen partial pressure during firing to become B 2 O 3 , which further reacts with other components to produce a boron-based low melting point substance, and the nozzle Sintering is significantly accelerated, resulting in a structure with poor spalling resistance. However, in the present invention, carbon black, which is ultrafine carbon particles added, coats the surface of boron carbide due to its adsorption ability, thus improving spalling resistance. Prevents the decomposition of boron carbide during firing, which causes deterioration. In addition, even if a low melting point substance is generated during firing, carbon such as carbon black has good dispersibility because it is an ultrafine particle, and will disperse in the low melting point substance, making the low melting point substance discontinuous. Prevents an increase in the elastic modulus of the fired body. Furthermore, during use of the nozzle, boron carbide generates a low melting point substance as described above, which becomes a liquid phase between particles and causes deterioration in the strength of the nozzle. However, in the present invention, ultrafine carbon particles have a low melting point. Since it is dispersed within the substance, it prevents strength deterioration by increasing the viscosity of the liquid phase. Next, specific examples of the raw materials used in the present invention and reasons for limitation will be described. Note that all percentages shown below are based on weight ratios. Alumina may be either fused or sintered.
The percentage is 40-65%. If it is less than 40%, the corrosion resistance of alumina cannot be exhibited, and if it is more than 65%, the spalling resistance of the nozzle is poor. The silica is selected from amorphous ones such as fused silica and amorphous silica, and the proportion thereof is 1 to 30%, more preferably 5 to 25%. If it is less than 1%, the low expansion properties of silica will not be fully expressed, resulting in poor spalling resistance of the nozzle, and if it is more than 30%, a large amount of low melting point substances will be produced, resulting in decreased corrosion resistance. The amount of boron carbide in the outer layer is 0.05 to 2%, more preferably 0.1 to 1.5% in the outer layer. If it is less than 0.05%, the oxidation resistance effect will not be sufficient, and if it is more than 2%, the hot strength will be poor and the addition amount will be too large, which is not preferable from an economic point of view. Carbon can be used regardless of whether it is crystalline or amorphous, such as scaly graphite, earthy graphite, electrode scraps, coke, pitch, carbon black, etc., and the proportion thereof is
10-45%. Below 10%, the corrosion resistance of the nozzle
Spalling resistance is insufficient, and 45% or more is unfavorable from the standpoint of oxidation resistance. In the present invention, 3 to 50% of the carbon is ultrafine carbon black having an average particle size of 5 μm or less. If it is less than 3%, the spalling resistance and hot strength are no different from conventional ones, and if it is more than 50%, the porosity increases, which is undesirable from the viewpoint of corrosion resistance. The proportion of carbon black above is based on the total carbon raw material being 100%, and when converted to the proportion of the entire blend including other raw materials alumina, silica, and boron carbide, it is 0.3 to 22.5%.
becomes. Further, in addition to the above raw materials, appropriate amounts of mullite, silicon carbide, silicon nitride, boron nitride, zirconia, metal powder, ceramic fiber, etc. may be added as long as they do not impair the effects of the present invention. The present invention adds binders such as tar pitch, creosote oil, CMC, PVA, pulp waste liquid, phenolic resin, furan resin, polyester resin, acrylonitrile resin, etc. to the above formulation,
It is obtained by kneading at room temperature, heating if necessary, rubber press molding into a desired shape, and then reducing and firing at 1000 to 1100°C. Next, examples of the present invention and comparative examples thereof will be shown. In each example, 5% of phenolic resin was added as a binder on the outside, kneaded, molded into a nozzle shape with a rubber press (pressure force 1000 kg/cm 2 ), and heated to 1000°C.
It was reduced and fired for 3 hours. The table test was conducted using a test piece cut from the nozzle. Apparent specific gravity, bulk specific gravity and porosity are
This was done based on JIS-R2205. The bending strength was measured at each temperature by placing a test piece of width 40 x thickness 20 x length 150 mm over a 100 mm span. The elastic modulus is width 30
A test piece with a thickness of 30 mm and a length of 150 mm was measured using an ultrasonic method. Oxidation loss was determined by heating a 30 x 30 x 30 mm test piece in an electric furnace at each temperature for 2 hours, and determining the weight difference between before and after heating as the oxidation loss.

【表】【table】

【表】 −は測定せず
* 1500℃×15分保定後、水冷
実炉試験は、100t鋼鍋に装着して6チヤージ使
用後、その溶損およびスポーリングの状態にもと
づいて測定した。 表の結果からも明らかなように、本発明により
得られる連続鋳造用ノズルは耐食性、熱間強度お
よび耐スポーリング性のいずれにおいても良好な
結果を示す。
[Table] - Not measured * After holding at 1500°C for 15 minutes, water cooling In the actual furnace test, the test piece was attached to a 100t steel pot and used for 6 charges, and measurements were taken based on the state of melting and spalling. As is clear from the results in the table, the continuous casting nozzle obtained by the present invention shows good results in terms of corrosion resistance, hot strength, and spalling resistance.

Claims (1)

【特許請求の範囲】[Claims] 1 重量割合で、アルミナ40〜65%、シリカ1〜
30%、炭素10〜45%、炭化硼素0.05〜2%(外
掛)とし、かつ、前記炭素のうち3〜25%(配合
物全体に占める割合0.3〜11.3%)が平均粒径5μ
以下のカーボンブラツクである配合物を混練、成
形後、還元焼成することを特徴とする連続鋳造用
ノズルの製造方法。
1 Weight percentage: 40-65% alumina, 1-1% silica
30% carbon, 10-45% carbon, 0.05-2% boron carbide (outer layer), and 3-25% of the carbon (0.3-11.3% of the total composition) has an average particle size of 5 μm.
A method for producing a continuous casting nozzle, which comprises kneading and molding the following carbon black compound, followed by reduction firing.
JP7987180A 1980-06-13 1980-06-13 Manufacture of continuous casting nozzle Granted JPS577868A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7987180A JPS577868A (en) 1980-06-13 1980-06-13 Manufacture of continuous casting nozzle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7987180A JPS577868A (en) 1980-06-13 1980-06-13 Manufacture of continuous casting nozzle

Publications (2)

Publication Number Publication Date
JPS577868A JPS577868A (en) 1982-01-16
JPS6348828B2 true JPS6348828B2 (en) 1988-09-30

Family

ID=13702274

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7987180A Granted JPS577868A (en) 1980-06-13 1980-06-13 Manufacture of continuous casting nozzle

Country Status (1)

Country Link
JP (1) JPS577868A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0285467A (en) * 1988-09-20 1990-03-26 Takenaka Komuten Co Ltd Foldable type shiftable scaffolding

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4682718A (en) * 1983-08-16 1987-07-28 Toshiba Ceramics Co., Ltd. Nozzle for continuous casting of molten steel
JPS60127261A (en) * 1983-12-12 1985-07-06 ハリマセラミック株式会社 Nozzle for molten steel casting
JPS6256354A (en) * 1985-05-20 1987-03-12 川崎炉材株式会社 Graphite-containing refractory brick
JPS62182156A (en) * 1986-02-05 1987-08-10 品川白煉瓦株式会社 Refractory composition for sliding nozzle and formation thereof
US5083687A (en) * 1989-10-19 1992-01-28 Kawasaki Steel Corporation Nozzle for continuous casting and method of producing
JPH03114639A (en) * 1990-08-17 1991-05-15 Harima Ceramic Co Ltd Nozzle for casting molten steel
IL104250A (en) * 1992-12-28 1995-10-31 Omat Ltd Controller for cnc-operated machine tools
DE4336269C2 (en) * 1993-10-23 1995-09-21 Veitsch Radex Ag Use of a refractory ceramic mass
JP3200378B2 (en) * 1996-11-18 2001-08-20 品川白煉瓦株式会社 Nozzle for continuous casting of aluminum killed steel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0285467A (en) * 1988-09-20 1990-03-26 Takenaka Komuten Co Ltd Foldable type shiftable scaffolding

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Publication number Publication date
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