JP2001191153A - Powder for continuously casting b-containing steel and continuous casting method - Google Patents
Powder for continuously casting b-containing steel and continuous casting methodInfo
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- JP2001191153A JP2001191153A JP37223499A JP37223499A JP2001191153A JP 2001191153 A JP2001191153 A JP 2001191153A JP 37223499 A JP37223499 A JP 37223499A JP 37223499 A JP37223499 A JP 37223499A JP 2001191153 A JP2001191153 A JP 2001191153A
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- powder
- continuous casting
- sio
- cao
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、Ｂ含有鋼の連続鋳
造に用いられるパウダーに関し、特に、溶融パウダーの
鋳造時における経時変化に起因して生じる鋳片の表面欠
陥や鋳造操業の不安定化を防止するための連続鋳造用パ
ウダーおよびこのパウダーを用いて行う連続鋳造方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder used for continuous casting of B-containing steel, and more particularly to a surface defect of a slab and an instability of a casting operation caused by a change with time during casting of a molten powder. TECHNICAL FIELD The present invention relates to a powder for continuous casting for preventing the occurrence of a crack, and a continuous casting method using the powder.
【０００２】[0002]
【従来の技術】鋼の連続鋳造では、鋳型と鋳片との間の
潤滑性を維持して、鋳片の表面性状を良好に保つため
に、連続鋳造用パウダーを鋳型内で溶融させ、溶融状態
のパウダー（溶融パウダー）を鋳型と鋳片との間に流入
させながら操業を行うのが一般的である。かかる連続鋳
造用パウダーの成分としては、一般に、CaＯおよびSiＯ
２を主成分として含有するものが使用されている。しか
しながら、この連続鋳造用パウダーを用いてＢ含有鋼
（主としてＢ含有ステンレス鋼）を連続鋳造した場合
に、溶融パウダー中のSiＯ２が溶鋼中のＢと (1)式のご
とく反応し、溶融パウダー中のＢ２Ｏ３濃度が上昇し
て、SiＯ２濃度が低下してしまう。 ４［Ｂ］・３（SiＯ２）＝２（Ｂ２Ｏ３）＋３［Si］…… (1) ただし、 ［Ｂ］：溶鋼中のＢ含有量（％） （SiＯ２）：溶融パウダー中のSiＯ２含有量（％） （Ｂ２Ｏ３）：溶融パウダー中のＢ２Ｏ３含有量（％） ［Si］：溶鋼中のSi含有量（％）2. Description of the Related Art In continuous casting of steel, powder for continuous casting is melted in a mold in order to maintain lubricity between the mold and the slab and maintain good surface properties of the slab. Generally, the operation is carried out while flowing the powder in a state (melted powder) between the mold and the slab. The components of such a powder for continuous casting are generally CaO and SiO.
Those containing 2 as a main component are used. However, when B-containing steel (mainly B-containing stainless steel) is continuously cast using the powder for continuous casting, SiO 2 in the molten powder reacts with B in the molten steel as shown in equation (1), and the molten powder is melted. The concentration of B 2 O 3 therein increases, and the concentration of SiO 2 decreases. 4 [B] · 3 (SiO 2 ) = 2 (B 2 O 3 ) +3 [Si] (1) where [B]: B content in molten steel (%) (SiO 2 ): in molten powder SiO 2 content of (%) (B 2 O 3 ): B 2 O 3 content in the molten powder (%) [Si]: Si content in the molten steel (%)
【０００３】このために、連続鋳造の操業中に溶融パウ
ダーの融点および粘度が著しく低下して、鋳型と鋳片と
の間に溶融パウダーの不均一な過剰流入を起こし、鋳片
表面に凹み欠陥や割れを生じ、鋳片の手入れ歩留を悪化
させるという問題があった。また、このような溶融パウ
ダーの特性の変化は、ブレークアウトなどの操業上のト
ラブルを起こしたり、生産性を低下させるという問題も
あった。ところで、Ｂ含有鋼の連続鋳造における上述し
たような問題に対処するための提案がこれまでにも幾つ
か行われている。例えば、特開平２−155547号公報や特
開平８−141712号公報には、CaＯおよびSiＯ２が主成分
である連続鋳造用パウダーに、予めＢ２Ｏ３を５〜30重
量％程度含有させることにより、（1)式の反応を抑制し
て、操業中における溶融パウダーの融点および粘度の変
化を少なくする技術が開示されている。また、特開平８
−309483号公報には、連続鋳造用パウダーの融点、鋳造
温度、鋳造速度、オッシレーション条件などを規定する
ことにより、溶融パウダーの不均一な過剰流入を防止す
ることで、鋳片表面品質および鋳造性の向上を図る技術
が示されている。[0003] As a result, the melting point and viscosity of the molten powder are significantly reduced during the continuous casting operation, causing an inhomogeneous excessive inflow of the molten powder between the mold and the slab, resulting in dent defects on the slab surface. Cracks occur and the yield of the slab is deteriorated. In addition, such a change in the characteristics of the molten powder causes problems such as breakout and other operational problems, and lowers productivity. By the way, several proposals have been made to address the above-mentioned problems in continuous casting of B-containing steel. For example, JP-A-2-155547 and JP 8-141712, the continuous casting powder CaO and SiO 2 as a main component, pre-B 2 O 3 to be contained 5 to 30 wt% Thus, a technique is disclosed in which the reaction of the formula (1) is suppressed to reduce changes in the melting point and viscosity of the molten powder during operation. Also, Japanese Patent Application Laid-Open
No. 309483 discloses that the melting point, casting temperature, casting speed, oscillation conditions and the like of the powder for continuous casting are specified to prevent uneven inflow of molten powder, thereby improving the slab surface quality and casting quality. A technique for improving the performance is shown.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記従
来技術では、Ｂ含有鋼の鋳片表面品質の劣化や操業トラ
ブルをある程度は改善することができるけれども、これ
らの防止策としては未だ完全とは言い難かった。すなわ
ち、主成分としてCaＯ／SiＯ２の値が比較的低い従来の
連続鋳造用パウダーの下では、Ｂ２Ｏ３を予め含有させ
ておいても、操業中における (1)式の反応による溶融パ
ウダーの粘度および融点の変化を十分には抑制すること
はできなかった。また、(1) 式の反応は、そもそも連続
鋳造操業中に起こるので、この反応の進行状況を操業時
に瞬時に把握することは難しく、したがって、連続鋳造
操業中に刻々と変化する連続鋳造用パウダーの融点に対
して最適な、鋳造温度、鋳造速度、オッシレーション条
件などを適宜設定することは困難であり、現実的ではな
い。However, in the above-mentioned prior art, although the deterioration of the surface quality of the slab of the B-containing steel and the operation trouble can be improved to some extent, it is still not perfect as a preventive measure for them. It was difficult. That is, under the conventional powder for continuous casting in which the value of CaO / SiO 2 is relatively low as the main component, even if B 2 O 3 is previously contained, the molten powder by the reaction of the formula (1) during the operation is used. , The changes in viscosity and melting point could not be sufficiently suppressed. In addition, since the reaction of equation (1) occurs during the continuous casting operation in the first place, it is difficult to grasp the progress of this reaction instantaneously at the time of the operation. It is difficult to appropriately set a casting temperature, a casting speed, an oscillation condition, and the like that are optimal with respect to the melting point, and this is not practical.
【０００５】本発明は、従来技術が抱えていた上記問題
を解決するための技術を提案するものであり、連続鋳造
鋳片の表面欠陥やブレークアウトなどの操業上のトラブ
ルを防止して、鋳造操業の全期間を通じて、表面性状が
優れた鋳片を、鋳造上のトラブルを招くことなく製造す
るための、Ｂ含有鋼の連続鋳造用パウダーおよびこのパ
ウダーを用いる連続鋳造方法を提供することを目的とす
る。また、本発明は、パウダーの物性値とくに粘度と融
点が連続鋳造操業の全期間にわたりほとんど変化しない
連続鋳造用パウダーを開発することを具体的課題とす
る。The present invention proposes a technique for solving the above-mentioned problems of the prior art. It is an object of the present invention to provide a powder for continuous casting of B-containing steel and a continuous casting method using the powder for producing a slab having excellent surface properties without causing casting problems throughout the entire operation. And Another object of the present invention is to develop a powder for continuous casting in which the physical properties of the powder, particularly the viscosity and the melting point, hardly change during the entire continuous casting operation.
【０００６】[0006]
【課題を解決するための手段】発明者らは、連続鋳造開
始から終了までの全期間にわたり、Ｂ含有鋼を連続鋳造
するときの溶融パウダーの物性（融点および粘度）の変
化と、連続鋳造用パウダーの構成成分との関係を詳細に
観察した結果、従来試みられたことのないCaＯ／SiＯ２
の高い範囲でとくに良好な鋳造が行え、鋳片の表面性状
も良好であることを知見した。このような知見に基づい
て完成した本発明の要旨構成は以下のとおりである。 (1)Ｂを0.1 ％以上含有する溶鋼を連続鋳造するための
連続鋳造用パウダーであって、重量％（以下、単に％）
にして、CaＯおよびSiＯ２をCaＯ＋SiＯ２：35〜70％、
かつCaＯ／SiＯ２：3.0 以上の範囲で含むとともに、Al
２Ｏ３：15〜30％およびＢ２Ｏ３：５〜30％を含有し、
融点：950 〜1250℃で、1300℃における粘度：0.8 〜
3.0 poiseの特性を有することを特徴とするＢ含有鋼の
連続鋳造用パウダー。Means for Solving the Problems The inventors of the present invention have studied the changes in the physical properties (melting point and viscosity) of molten powder during continuous casting of a B-containing steel, and the effects of continuous casting. result of observation of the relationship between the powder components in detail, that has not been attempted conventionally CaO / SiO 2
It has been found that particularly good casting can be performed in a high range, and that the surface properties of the slab are also good. The gist configuration of the present invention completed based on such knowledge is as follows. (1) A powder for continuous casting for continuously casting molten steel containing 0.1% or more of B, wherein the weight% (hereinafter simply referred to as%)
Then, CaO and SiO 2 are converted into CaO + SiO 2 : 35 to 70%,
And CaO / SiO 2 : not less than 3.0 and Al
2 O 3 : 15 to 30% and B 2 O 3 : 5 to 30%,
Melting point: 950-1250 ° C, viscosity at 1300 ° C: 0.8-
A powder for continuous casting of B-containing steel, having a characteristic of 3.0 poise.
【０００７】(2)連続鋳造用パウダーを用いて、Ｂを0.1
％以上含有する溶鋼を連続鋳造するに際し、この連続
鋳造用パウダーとして、重量％で、CaＯおよびSiＯ２を
CaＯ＋SiＯ２：35〜70％、かつCaＯ／SiＯ２：3.0 以上
の範囲で含むとともに、Al２Ｏ ３：15〜30％およびＢ２
Ｏ３：５〜30％を含有し、融点：950 〜1250℃で、1300
℃における粘度：0.8 〜 3.0 poiseの特性を有するパウ
ダーを用いることを特徴とするＢ含有鋼の連続鋳造方
法。(2) B is adjusted to 0.1 using a powder for continuous casting.
% When continuously casting molten steel containing at least
CaO and SiO by weight as casting powder2To
CaO + SiO2: 35-70% and CaO / SiO2： 3.0 or more
Al2O 3: 15-30% and B2
O3: 5 to 30%, melting point: 950 to 1250 ° C, 1300
Viscosity at ℃: Paw with characteristics of 0.8 to 3.0 poise
Continuous casting of B-containing steel characterized by using
Law.
【０００８】[0008]
【発明の実施の形態】発明者らは、Ｂ含有鋼の鋳片表面
品質劣化および難鋳造性の原因について調査し、これが
連続鋳造操業中における連続鋳造用パウダーの物性とく
に粘度および融点が大幅に変化するためであることを確
認した。すなわち、Ｂ含有鋼の連続鋳造では、 (1)式の
反応が右向きに進行することにより、溶鋼中のＢが溶融
パウダー中のSiＯ２を還元し、溶融パウダー中のSiＯ２
が低下しＢ２Ｏ３が増加する結果、溶融パウダーの融点
および粘度が大幅に低下する。このため、連続鋳造操業
の全期間を通して物性値を良好に維持することが困難と
なり、溶融パウダーの不均一な過剰流入が起こり、鋳片
表面に凹みや割れなどの表面欠陥を生じたり、ブレーク
アウトなどの操業上のトラブルを起こしやすくなるので
ある。BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have investigated the causes of deterioration of the slab surface quality and poor castability of B-containing steel and found that the physical properties of the powder for continuous casting during the continuous casting operation, particularly the viscosity and melting point, were significantly reduced. I confirmed that it was because of change. That is, in the continuous casting of B-containing steel, the reaction in equation (1) proceeds rightward, so that B in the molten steel reduces SiO 2 in the molten powder, and SiO 2 in the molten powder.
There decreased B 2 results O 3 is increased, the melting point and viscosity of the molten powder is greatly reduced. As a result, it is difficult to maintain good physical properties throughout the entire continuous casting operation, causing an excessive influx of molten powder, causing surface defects such as dents and cracks on the slab surface, and breakout. Operational troubles such as this are more likely to occur.
【０００９】図１および図２は、従来から通常用いられ
てきた連続鋳造用パウダーを用いて、Ｂ含有鋼を連続鋳
造した際における、溶融パウダーの組成変化を示してい
る。連続鋳造用パウダーＡはCaＯおよびSiＯ２が主成分
のもの、連続鋳造用パウダーＢはCaＯおよびSiＯ２のほ
かＢ２Ｏ３を含有するものである。図１及び２におい
て、パウダーＡ、Ｂのいずれもが、鋳造開始から10分ま
での間に、溶融パウダー中のＢ２Ｏ３が急激に上昇し、
SiＯ２は急激に低下している。この間の、パウダーの融
点および粘度の変化は、パウダーＢで代表して示すよう
に、大幅に低下する。パウダーＢは、 (1)式の反応の進
行を抑制するために、パウダー中に予めＢ２Ｏ３を添加
したものであるが、図１、２に示すように、現実には
(1)式の反応を完全には抑制できていない。このような
現象がもたらされた理由は、Ｂ２Ｏ３を添加したとき
に、パウダーの融点および粘度が低下してしまうため、
この融点および粘度を適正に維持するために、Na、Ｆの
量や、CaＯ／SiＯ２などを調整しなくてはならなくな
り、このために (1)式の反応の右向きへの進行を抑制す
るに必要な、パウダー中の成分バランスがくずれてしま
うからであると思われる。FIGS. 1 and 2 show a change in the composition of a molten powder when a B-containing steel is continuously cast by using a conventionally used powder for continuous casting. The powder A for continuous casting contains CaO and SiO 2 as main components, and the powder B for continuous casting contains B 2 O 3 in addition to CaO and SiO 2 . 1 and 2, in both powders A and B, B 2 O 3 in the molten powder rapidly increased during 10 minutes from the start of casting,
SiO 2 is rapidly decreasing. During this time, the changes in the melting point and the viscosity of the powder are greatly reduced as shown by powder B. Powder B is obtained by adding B 2 O 3 in advance in the powder in order to suppress the progress of the reaction of the formula (1). However, as shown in FIGS.
The reaction of equation (1) has not been completely suppressed. The reason that such a phenomenon was brought about is that, when B 2 O 3 is added, the melting point and the viscosity of the powder are reduced.
In order to maintain the melting point and viscosity properly, it is necessary to adjust the amounts of Na and F, CaO / SiO 2, etc., thereby suppressing the rightward progress of the reaction of the formula (1). This is because the component balance in the powder, which is necessary for the above, is lost.
【００１０】このように、CaＯおよびSiＯ２が主成分で
ある従来の連続鋳造用パウダーを使用する場合には、予
めＢ２Ｏ３を含有させておいても、操業中における (1)
式の反応による溶融パウダーの粘度および融点の変化を
完全に抑制することはできない。そこで発明者らは、溶
鋼中のＢとパウダーがほとんど反応することがなく、安
定した連続鋳造が可能な連続鋳造用パウダーについて、
多くの実験を行い検討した。その結果、 (1)式の反応の
もとになるSiＯ２の含有量を、CaＯ／SiＯ２（重量％比
率）の値で3.0 以上、好ましくは5.0 以上の範囲となる
よう十分少なくすることで、 (1)式の反応による溶融パ
ウダーの粘度および融点の変化をほぼ抑制できることを
見出した。なお、このときに、CaＯとSiＯ２の合計含有
量（CaＯ＋SiＯ２）は35〜70％の範囲とすることも必要
である。というのは、この量が３５％未満では溶融パウ
ダーの融点と粘度の調整が困難となり、適正な物性値が
得られないからである。一方、７０％を超えるとパウダ
ーが高融点となりすぎて、溶融パウダーの流入不足を起
こす可能性があるからである。As described above, when a conventional powder for continuous casting containing CaO and SiO 2 as main components is used, even if B 2 O 3 is contained in advance, (1)
Changes in the viscosity and melting point of the molten powder due to the reaction of the formula cannot be completely suppressed. Therefore, the present inventors have proposed a powder for continuous casting in which B and powder in molten steel hardly react with each other and stable continuous casting is possible.
A number of experiments were performed and discussed. As a result, the content of SiO 2 , which is the basis of the reaction of the formula (1), can be sufficiently reduced so as to be in a range of 3.0 or more, preferably 5.0 or more in terms of CaO / SiO 2 (weight% ratio). It has been found that changes in the viscosity and melting point of the molten powder due to the reaction of the formula (1) can be substantially suppressed. At this time, the total content of CaO and SiO 2 (CaO + SiO 2 ) also needs to be in the range of 35 to 70%. This is because if the amount is less than 35%, it is difficult to adjust the melting point and viscosity of the molten powder, and an appropriate physical property value cannot be obtained. On the other hand, if it exceeds 70%, the powder will have an excessively high melting point, which may cause insufficient inflow of the molten powder.
【００１１】このように、適正に成分調整した連続鋳造
用パウダーは、 (1)式の反応を抑制できるほどにSiＯ２
含有量が十分に低いので、操業中における溶融パウダー
の粘度、融点の変化をほば抑制することができ、その結
果、鋳片表面性状の劣化および操業トラブルの原因とな
る、溶融パウダーの不均一な過剰流入を防止できるので
ある。CaＯ／SiＯ２を上記範囲に定めるとともに、CaＯ
＋SiＯ２を所定の範囲に定めた場合であっても、少量の
SiＯ２がパウダーと反応する可能性も僅かにあるため、
本発明においては、Ｂ２Ｏ３を予めパウダー中に５〜30
％含有させる。Ｂ２Ｏ ３が５％未満では (1)式の抑制に
効果的ではなく、一方、30％を超えて含有させるとパウ
ダーの融点および粘度が極度に低くなり、溶融パウダー
の過剰流入による鋳片の表面品質悪化を招いてしまう。
なお、Ｂ２Ｏ３の好ましい含有量は５〜25％である。[0011] As described above, continuous casting with properly adjusted components.
The powder for use is made of SiO enough to suppress the reaction of equation (1).2
The content is low enough to ensure that the
Changes in viscosity and melting point of
As a result, it may cause deterioration of slab surface properties and operation trouble.
To prevent uneven inflow of molten powder
is there. CaO / SiO2Within the above range, and CaO
+ SiO2Even if the specified range is
SiO2May react slightly with the powder,
In the present invention, B2O3Beforehand in powder 5-30
%. B2O 3Is less than 5%, the equation (1) is suppressed.
It is not effective, but if it contains more than 30%
Melting point and viscosity are extremely low,
Excessive inflow of steel causes deterioration of the surface quality of the slab.
Note that B2O3Is preferably 5 to 25%.
【００１２】本発明の連続鋳造用パウダーは、上記した
CaＯ、SiＯ２、Ｂ２Ｏ３のほか、さらにAl２Ｏ３を含む
ことも必要である。このAl２Ｏ３の含有量が15％未満で
は、パウダーの融点と粘度の調整が困難となり、適正な
物性値が得られなくなる。30％を超えるとパウダーの融
点および粘度が高くなりすぎ、溶融パウダーの流入不足
によるブレークアウトの原因になるので、このAl２Ｏ３
含有量は15〜30％の範囲とする。上述のCaＯ、SiＯ２、
Ｂ２Ｏ３およびAl２Ｏ３からなる主成分のほか、Zr
Ｏ２ 、TiＯ２ 、 Na、Ｆ、Ｃのうちから選ばれる成分
を５〜50％の範囲で適宜含有させることが好ましい。ま
た、これらの供給源である原料から不可避的に入るFe
Ｏ、MnＯ、MgＯなどを不純物として含んでもよい。[0012] The powder for continuous casting of the present invention is as described above.
CaO, SiO2, B2O3In addition to Al2O3including
It is also necessary. This Al2O3Less than 15%
Makes it difficult to adjust the melting point and viscosity of the powder,
Physical property values cannot be obtained. If it exceeds 30%, the powder will melt.
Point and viscosity too high, insufficient inflow of molten powder
This Al will cause a breakout due to2O3
The content is in the range of 15 to 30%. The above-mentioned CaO, SiO2,
B2O3And Al2O3In addition to the main component consisting of
O2 , TiO2, Na, F, C
Is preferably contained in the range of 5 to 50%. Ma
In addition, Fe that inevitably enters from the raw materials
O, MnO, MgO, etc. may be contained as impurities.
【００１３】さらに、発明者らは、Ｂ含有鋼を連続鋳造
する際の、適正なパウダーの物性値ついても検討した。
その結果、連続鋳造用パウダーの融点および粘度は、そ
れぞれ融点： 950℃〜1250℃で、1300℃における粘度：
0.8 poise 〜3.0 poise の範囲にあることがよく、本発
明パウダーはこれらの物性値を満たしていることが明ら
かとなった。溶融パウダーの融点が950 ℃未満の低融点
や 1300 ℃における粘度が0.8 poise 未満の低粘度にな
ると、鋳型と鋳片との間に溶融パウダー流入量が極度に
多くなり、不均一な過剰流入を起こすようになるため、
鋳片の表面性状が低下し、鋳片の手入れ歩留が悪化す
る。一方、融点が1250℃を超える高融点となったり、13
00℃における粘度が3.0 poise を超える高粘度では、鋳
型と鋳片との間に溶融パウダーの流入量が極度に少なく
なり、鋳型と鋳片との間の潤滑不足をきたすために、ブ
レークアウトなどの操業上のトラブルを起こし、生産性
を著しく低下させる。このことから、溶融パウダーの流
入量を適正にコントロールするためには、連続鋳造用パ
ウダーの融点は 950〜1250℃、1300℃における粘度は
0.8〜3.0 poise とする、なお、これら物性値の好まし
い範囲は、融点：1000〜1200℃、1300℃における粘度：
1.0 〜3.0 poise である。Further, the present inventors have also studied the proper physical properties of the powder when the B-containing steel is continuously cast.
As a result, the melting point and viscosity of the powder for continuous casting were as follows: melting point: 950 ° C. to 1250 ° C .;
It is well within the range of 0.8 poise to 3.0 poise, and it is clear that the powder of the present invention satisfies these physical properties. If the melting point of the molten powder is lower than 950 ° C or the viscosity at 1300 ° C is lower than 0.8 poise, the amount of molten powder flowing between the mold and the slab becomes extremely large, causing uneven overflow. To get up,
The surface properties of the slab are reduced, and the care yield of the slab is deteriorated. On the other hand, the melting point becomes higher than 1250 ° C,
If the viscosity at 00 ° C exceeds 3.0 poise, the flow of molten powder between the mold and the slab becomes extremely small, causing insufficient lubrication between the mold and the slab. Causes operational problems and significantly reduces productivity. Therefore, in order to properly control the inflow amount of the molten powder, the melting point of the powder for continuous casting should be 950 to 1250 ° C and the viscosity at 1300 ° C should be
The preferable range of these physical property values is 0.8 to 3.0 poise, melting point: 1000 to 1200 ° C, viscosity at 1300 ° C:
1.0 to 3.0 poise.
【００１４】図５および図６は、本発明にしたがう連続
鋳造用パウダー（CaＯ＋SiＯ２：43.0％、CaＯ／Si
Ｏ２：7.4 、Al２Ｏ３：24.0％、Ｂ２Ｏ３：16.0％、N
a：8.0 ％、Ｆ：2.0 ％、融点：1100℃、1300℃におけ
る粘度：1.8 poise ）を用いてＢ含有鋼を連続鋳造した
際の、それぞれパウダー中のＢ２Ｏ３量、SiＯ２量の変
化を示したものである。図５および図６から明らかなよ
うに、本発明パウダーは連続鋳造操業の全期間を通し
て、これら組成の変化はほとんどみられない。このこと
から本発明パウダーを用いて連続鋳造すれば、操業中に
おける溶融パウダーの粘度および融点の変化も抑制し
て、適正なパウダー物性値を保持でき、安定した鋳造が
可能であること表している。FIGS. 5 and 6 show powders for continuous casting according to the present invention (CaO + SiO 2 : 43.0%, CaO / Si
O 2 : 7.4, Al 2 O 3 : 24.0%, B 2 O 3 : 16.0%, N
a: 8.0%, F: 2.0%, melting point: 1100 ° C., viscosity at 1300 ° C .: 1.8 poise), when the B-containing steel was continuously cast using the B 2 O 3 amount and the SiO 2 amount in the powder, respectively. It shows the change. As is clear from FIGS. 5 and 6, the powder of the present invention shows almost no change in its composition throughout the continuous casting operation. From this, if continuous casting is performed using the powder of the present invention, changes in the viscosity and melting point of the molten powder during operation can be suppressed, and appropriate powder physical property values can be maintained, indicating that stable casting is possible. .
【００１５】[0015]
【実施例】組成とその物性が異なる種々の連続鋳造用パ
ウダーを用いて、表１に示す各条件でＢ含有鋼の連続鋳
造を行った。鋳造開始前と鋳造後の溶融パウダーの物性
値を測定するとともに、鋳造結果と、鋳片表面の欠陥除
去を行うときの手入れ歩留を併記する。なお、粘度は共
軸２重回転円筒法により1300℃における粘度を測定した
値であり、融点は共軸２重回転円筒法により各温度で粘
度の測定を繰り返し、アレニウス型の温度依存性から大
きく逸脱する点を融点として求めたものである。EXAMPLES Continuous casting of B-containing steel was carried out under various conditions shown in Table 1 by using various continuous casting powders having different compositions and physical properties. The physical properties of the molten powder before and after the casting are measured, and the casting results and the maintenance yield when removing defects on the slab surface are also described. The viscosity is a value obtained by measuring the viscosity at 1300 ° C. by the coaxial double rotation cylinder method, and the melting point is repeatedly measured at each temperature by the coaxial double rotation cylinder method. The point deviating was determined as the melting point.
【００１６】[0016]
【表１】 [Table 1]
【００１７】[0017]
【表２】 [Table 2]
【００１８】表２から、本発明パウダーを使用して、Ｂ
含有鋼を連続鋳造した場合には、溶融パウダーの粘度お
よび融点の変化をほぼ完全に抑制できており、鋳造の全
期間を通じて適正なパウダー物性で操業ができ、鋳造性
も良好であり、鋳片の手入れ歩留も96％以上となり極め
て良好な結果が得られた。これに対し、CaＯおよびSiＯ
２が主成分であるか、これら主成分に加えてＢ２Ｏ３を
含有する、従来の連続鋳造用パウダーを使用して鋳造し
た比較例では、操業中における (1)式の反応による溶融
パウダーの粘度および融点の変化を完全に抑制すること
はできず、結果として、パウダー物性値が本発明範囲か
ら大きく外れることが避けられず、鋳片の手入れ歩留は
低下した。なお、比較例７は、CaＯおよびSiＯ２の主成
分のほかＢ２Ｏ３を含有する従来の連続鋳造用パウダー
を使用したものであり、溶融パウダーの粘度および融点
の変化をほば抑制できたにもかかわらず、1300℃におけ
る粘度が高すぎたために、潤滑不良によりブレークアウ
トを起こしてしまったものである。比較例２は、過度に
低融点、低粘度となったために、極端な不均一流入とな
り、鋼の凝固が遅れた部分からブレークアウトを起こ
し、鋳造中止となったものである。このように、従来の
連続鋳造用パウダーでは、鋳造中における溶融パウダー
の粘度・融点の変化の程度を予測することができず、溶
融パウダーの流入量を適正に制御することは難しい。From Table 2, using the powder of the present invention,
When the steel containing steel is continuously cast, the changes in the viscosity and melting point of the molten powder can be almost completely suppressed, the operation can be performed with proper powder properties throughout the casting period, the castability is good, and the slab The maintenance yield was 96% or more, and extremely good results were obtained. On the other hand, CaO and SiO
In a comparative example cast using a conventional powder for continuous casting containing 2 as a main component or containing B 2 O 3 in addition to these main components, the molten powder obtained by the reaction of the formula (1) during operation was used. The changes in the viscosity and the melting point of the slab could not be completely suppressed, and as a result, the powder physical properties were inevitably deviated from the range of the present invention, and the maintenance yield of the slab was reduced. In Comparative Example 7, the conventional continuous casting powder containing B 2 O 3 in addition to the main components of CaO and SiO 2 was used, and changes in the viscosity and melting point of the molten powder could be almost suppressed. Nevertheless, the viscosity at 1300 ° C. was too high, causing a breakout due to poor lubrication. In Comparative Example 2, since the melting point and the viscosity were excessively low, an extremely uneven inflow was caused, a breakout occurred from a portion where the solidification of the steel was delayed, and the casting was stopped. As described above, with the conventional powder for continuous casting, it is difficult to predict the degree of change in the viscosity and melting point of the molten powder during casting, and it is difficult to appropriately control the inflow amount of the molten powder.
【００１９】[0019]
【発明の効果】以上説明したように、本発明によれば、
Ｂ含有鋼の連続鋳造における溶融パウダー中のＢ２Ｏ３
の上昇とSiＯ２の低下による、溶融パウダーの融点およ
び粘度の変動をほぼ完全に防止することができ、溶融パ
ウダーの流入量を適正に制御でき、パウダーの過剰流入
や流入不足を防止することができるようになる。したが
って、本発明によれば、溶融パウダーの鋳造期間中での
物性変化に起因して生じる、鋳片表面欠陥の発生を防止
でき、手入れ歩留を向上させることができる。また、溶
融パウダーの潤滑不良によるブレークアウト等の操業ト
ラブルをも防止することができる。As described above, according to the present invention,
B 2 O 3 in molten powder in continuous casting of B-containing steel
Fluctuation in melting point and viscosity of the molten powder due to the rise in the temperature and the decrease in the amount of SiO 2 can be almost completely prevented, the inflow amount of the molten powder can be appropriately controlled, and the excessive inflow or insufficient inflow of the powder can be prevented. become able to. Therefore, according to the present invention, it is possible to prevent a slab surface defect from occurring due to a change in the physical properties of the molten powder during the casting period, and to improve the maintenance yield. Further, operation troubles such as breakout due to poor lubrication of the molten powder can be prevented.
【図１】CaＯおよびSiＯ２を主成分として、或いはさら
にＢ２Ｏ３を含有する従来の連続鋳造用パウダーを使用
して、Ｂ含有鋼を連続鋳造した場合の、溶融パウダー中
のＢ２Ｏ３含有量の変化を示した図である。The [1] CaO and SiO 2 as main components, or even using a conventional continuous casting powder containing B 2 O 3, in the case of the B containing steel was continuously cast, B 2 O in the molten powder FIG. 3 is a diagram showing a change in 3 content.
【図２】CaＯおよびSiＯ２を主成分として、或いはさら
にＢ２Ｏ３を含有する従来の連続鋳造用パウダーを使用
して、Ｂ含有鋼を連続鋳造した場合の、溶融パウダー中
のSiＯ２含有量の変化を示した図である。FIG. 2 shows the content of SiO 2 in a molten powder when a B-containing steel is continuously cast using CaO and SiO 2 as main components or a conventional continuous casting powder further containing B 2 O 3. It is a figure showing a change of the amount.
【図３】CaＯおよびSiＯ２を主成分として、或いはさら
にＢ２Ｏ３を含有する従来の連続鋳造用パウダーを使用
して、Ｂ含有鋼を連続鋳造した場合の、溶融パウダーの
1300℃における粘度の変化を示した図である。FIG. 3 shows a molten powder obtained by continuously casting a B-containing steel using CaO and SiO 2 as main components or a conventional continuous casting powder further containing B 2 O 3 .
FIG. 3 is a diagram showing a change in viscosity at 1300 ° C.
【図４】CaＯおよびSiＯ２を主成分として、或いはさら
にＢ２Ｏ３を含有する従来の連続鋳造用パウダーを使用
して、Ｂ含有鋼を連続鋳造した場合の、溶融パウダーの
融点の変化を示した図である。FIG. 4 shows the change in the melting point of molten powder when B-containing steel is continuously cast using CaO and SiO 2 as main components or further using a conventional continuous casting powder further containing B 2 O 3. FIG.
【図５】本発明に従う連続鋳造用パウダーを使用して、
Ｂ含有鋼を連続鋳造した場合の、溶融パウダー中のＢ２
Ｏ３含有量の変化を示した図である。FIG. 5: Using the powder for continuous casting according to the present invention,
B 2 in molten powder when B-containing steel is continuously cast
O 3 is a view showing a change in content.
【図６】本発明に従う連続鋳造用パウダーを使用して、
Ｂ含有鋼を連続鋳造した場合の、溶融パウダー中のSiＯ
２含有量の変化を示した図である。FIG. 6: Using the powder for continuous casting according to the present invention,
SiO in molten powder when B-containing steel is continuously cast
FIG. 2 is a diagram showing a change in 2 content.
【図７】物性値が異なる連続鋳造用パウダーを用いて、
Ｂ含有鋼を連続鋳造した場合の、鋳造後パウダー物性値
と鋳片の手入れ歩留との関係を示した図である。[FIG. 7] Using continuous casting powders having different physical property values,
FIG. 4 is a view showing a relationship between a powder physical property value after casting and a maintenance yield of a slab when a B-containing steel is continuously cast.
フロントページの続き (72)発明者 田中 秀毅 神奈川県川崎市川崎区小島町４番２号 日 本冶金工業株式会社川崎製造所内 (72)発明者 本郷 敦哉 神奈川県川崎市川崎区小島町４番２号 日 本冶金工業株式会社川崎製造所内 Ｆターム(参考） 4E004 MB14 NC04 Continued on the front page (72) Inventor Hideki Tanaka 4-2 Kojima-cho, Kawasaki-ku, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Nippon Metallurgical Co., Ltd. Kawasaki Works (72) Inventor Atsushiya Hongo 4-2 Kojima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture No. Nihon Metallurgical Industry Co., Ltd. Kawasaki Works F-term (reference) 4E004 MB14 NC04
Claims (2)
るための連続鋳造用パウダーであって、重量％にして、
CaＯおよびSiＯ２をCaＯ＋SiＯ２：35〜70％、かつCaＯ
／SiＯ２：3.0 以上の範囲で含むとともに、Al２Ｏ３：
15〜30％およびＢ２Ｏ３：５〜30％を含有し、融点：95
0 〜1250℃で、1300℃における粘度：0.8 〜 3.0 poise
の特性を有することを特徴とするＢ含有鋼の連続鋳造用
パウダー。1. A continuous casting powder for continuously casting molten steel containing 0.1% or more of B, comprising:
CaO and SiO 2 : CaO + SiO 2 : 35 to 70%, and CaO
/ SiO 2: with including 3.0 or more ranges, Al 2 O 3:
15% to 30% and B 2 O 3: contains 5 to 30%, mp: 95
0 to 1250 ° C, viscosity at 1300 ° C: 0.8 to 3.0 poise
A powder for continuous casting of B-containing steel, having the following characteristics:
以上含有する溶鋼を連続鋳造するに際し、この連続鋳造
用パウダーとして、重量％で、CaＯおよびSiＯ２をCaＯ
＋SiＯ２：35〜70％、かつCaＯ／SiＯ２：3.0 以上の範
囲で含むとともに、Al２Ｏ３：15〜30％およびＢ
２Ｏ３：５〜30％を含有し、融点：950 〜1250℃で、13
00℃における粘度：0.8 〜 3.0 poiseの特性を有するパ
ウダーを用いることを特徴とするＢ含有鋼の連続鋳造方
法。2. B is 0.1% by using a powder for continuous casting.
When continuously casting molten steel containing the above, CaO and SiO 2 are converted into CaO by weight% as a powder for continuous casting.
+ SiO 2 : 35 to 70%, and CaO / SiO 2 : 3.0 or more, and Al 2 O 3 : 15 to 30% and B
2 O 3 : containing 5 to 30%, melting point: 950 to 1250 ° C., 13
A continuous casting method for B-containing steel, characterized by using a powder having a viscosity at 00 ° C of 0.8 to 3.0 poise.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP37223499A JP3383630B2 (en) | 1999-12-28 | 1999-12-28 | Powder for continuous casting of B-containing steel and continuous casting method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP37223499A JP3383630B2 (en) | 1999-12-28 | 1999-12-28 | Powder for continuous casting of B-containing steel and continuous casting method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001191153A true JP2001191153A (en) | 2001-07-17 |
| JP3383630B2 JP3383630B2 (en) | 2003-03-04 |
Family
ID=18500094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP37223499A Expired - Fee Related JP3383630B2 (en) | 1999-12-28 | 1999-12-28 | Powder for continuous casting of B-containing steel and continuous casting method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3383630B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007061846A (en) * | 2005-08-31 | 2007-03-15 | Nippon Yakin Kogyo Co Ltd | Continuous casting powder for boron-containing stainless steel, and continuous casting method |
| JP2007090367A (en) * | 2005-09-27 | 2007-04-12 | Sumitomo Metal Ind Ltd | Method for continuously casting boron-containing stainless steel |
| KR101064988B1 (en) | 2004-04-21 | 2011-09-15 | 주식회사 포스코 | Fluorine free boron oxide system mold flux for continuous casting of steel slab |
| KR101064987B1 (en) | 2004-04-21 | 2011-09-15 | 주식회사 포스코 | Fluorine free mold flux for continuous casting of steel slab |
| JP2011183424A (en) * | 2010-03-08 | 2011-09-22 | Nippon Yakin Kogyo Co Ltd | Powder for casting boron-containing stainless steel and method of continuously casting boron-containing stainless steel |
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1999
- 1999-12-28 JP JP37223499A patent/JP3383630B2/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101064988B1 (en) | 2004-04-21 | 2011-09-15 | 주식회사 포스코 | Fluorine free boron oxide system mold flux for continuous casting of steel slab |
| KR101064987B1 (en) | 2004-04-21 | 2011-09-15 | 주식회사 포스코 | Fluorine free mold flux for continuous casting of steel slab |
| JP2007061846A (en) * | 2005-08-31 | 2007-03-15 | Nippon Yakin Kogyo Co Ltd | Continuous casting powder for boron-containing stainless steel, and continuous casting method |
| JP4611153B2 (en) * | 2005-08-31 | 2011-01-12 | 日本冶金工業株式会社 | Continuous casting powder for boron-containing stainless steel and continuous casting method |
| JP2007090367A (en) * | 2005-09-27 | 2007-04-12 | Sumitomo Metal Ind Ltd | Method for continuously casting boron-containing stainless steel |
| JP4556823B2 (en) * | 2005-09-27 | 2010-10-06 | 住友金属工業株式会社 | Continuous casting method of B-containing stainless steel |
| JP2011183424A (en) * | 2010-03-08 | 2011-09-22 | Nippon Yakin Kogyo Co Ltd | Powder for casting boron-containing stainless steel and method of continuously casting boron-containing stainless steel |
| KR102288415B1 (en) * | 2020-03-18 | 2021-08-10 | 주식회사 포스코 | Tundish flux and casting method using the same |
| WO2021187749A1 (en) * | 2020-03-18 | 2021-09-23 | 주식회사 포스코 | Tundish flux and casting method using same |
| CN115279514A (en) * | 2020-03-18 | 2022-11-01 | 株式会社Posco | Tundish covering slag and casting method using same |
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| Publication number | Publication date |
|---|---|
| JP3383630B2 (en) | 2003-03-04 |
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