JPH0976049A - Flux for continuous casting of molten steel containing aluminum and continuous casting method - Google Patents
Flux for continuous casting of molten steel containing aluminum and continuous casting methodInfo
- Publication number
- JPH0976049A JPH0976049A JP26091295A JP26091295A JPH0976049A JP H0976049 A JPH0976049 A JP H0976049A JP 26091295 A JP26091295 A JP 26091295A JP 26091295 A JP26091295 A JP 26091295A JP H0976049 A JPH0976049 A JP H0976049A
- Authority
- JP
- Japan
- Prior art keywords
- flux
- continuous casting
- molten steel
- sio
- 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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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、含Al溶鋼連続鋳
造に用いるためのフラックス及び連続鋳造方法に関し、
特に含Al溶鋼を連続鋳造した際に鋳片表面にデプレッ
ション等の欠陥が生じないようにすることができる連続
鋳造用フラックス及び連続鋳造方法に関する。TECHNICAL FIELD The present invention relates to a flux and a continuous casting method for use in continuous casting of molten steel containing Al.
In particular, the present invention relates to a continuous casting flux and a continuous casting method capable of preventing defects such as depletion from occurring on the surface of a slab when continuously casting Al-containing molten steel.
【0002】[0002]
【従来の技術】鋼の連続鋳造では鋳型の鋳片との潤滑性
や鋳片の表面性状を良好にするために、溶融フラックス
を流入しながら操業されている。鋳型に流入されたフラ
ックスは溶融し鋳型内の溶鋼の表面上に滞留して層を形
成し、溶鋼の酸化を防止し、一部は溶鋼と鋳型の側面と
の間に入って冷却により降下しから形成されていく鋳片
と鋳型との間での潤滑作用を行う。このため、鋳型と鋳
片との潤滑性や鋳片の表面性状を良好にするようなフラ
ックスが使用されており、この種の連続鋳造用フラック
スとしては、従来CaO,SiO2 を主成分として含有
するものが使用されており、その組成としては、塩基度
(CaO/SiO2 )が0.8、融点が1000℃以
上、1300℃における粘性が1.5ポイズ以上の物性
をもつような組成を有するのが普通であるといわれてい
る。2. Description of the Related Art In continuous casting of steel, in order to improve the lubricity with the cast pieces of the mold and the surface properties of the cast pieces, operation is carried out while injecting a molten flux. The flux flowing into the mold melts and stays on the surface of the molten steel in the mold to form a layer, which prevents oxidation of the molten steel, and part of it enters between the molten steel and the side surface of the mold and drops by cooling. Lubricates between the slab and the mold that are being formed from. Therefore, a flux that improves the lubricity between the mold and the slab and the surface properties of the slab is used, and as a flux for continuous casting of this type, conventionally, CaO and SiO 2 are mainly contained. As the composition, a composition having a basicity (CaO / SiO 2 ) of 0.8, a melting point of 1000 ° C. or more and a viscosity at 1300 ° C. of 1.5 poises or more is used. It is said that it is common to have.
【0003】前述のようなCaO,SiO2 を主成分と
した通常の連続鋳造用フラックスを使用して溶鋼の連続
鋳造を行う場合、鋳造中にフラックスの組成が変動する
などして、フラックスの物性の変動があると、連鋳操業
が不安定となり、色々な障害が起こる。例えば、鋳片表
面のデプレション(へこみ欠陥)、ノロカミ等や、鋳片
が拘束されてブレークアウトが起こることもある。ま
た、鋼の連続鋳造においては、その鋼の種類によって連
続鋳造が容易なものと、難しいものがある。その難鋳造
鋼種としては、Alを含有する鋼があり、これは代表的
なものである。この含Al溶鋼を前記フラックスを用い
て連続鋳造を行うと次のような問題が発生する。すなわ
ち、鋳型内でのスラブリムの肥大化が生じ、パウダー流
入不良を起こしてブレークアウト等の操業トラブル発生
の危険が大きくなり、鋳片表面も悪化する。特開昭63
−10052号では、この原因は、溶鋼中のAlとフラ
ックスとが反応してゲーレナイト(2CaO Al2 O
3 SiO2 )が析出することに起因するものと解析し
ている。When continuous casting of molten steel is carried out by using the usual continuous casting flux containing CaO and SiO 2 as the main components as described above, the composition of the flux changes during casting and the physical properties of the flux are If there is a change in the continuous casting operation, the continuous casting operation becomes unstable and various obstacles occur. For example, a depletion (a dent defect) on the surface of the slab, a dent, etc., or a breakout may occur due to the slab being restrained. Further, in continuous casting of steel, depending on the type of steel, continuous casting is easy or difficult. As the difficult-to-cast steel type, there is a steel containing Al, which is typical. When this molten aluminum-containing steel is continuously cast using the above flux, the following problems occur. That is, the slabrim is enlarged in the mold, which causes a powder inflow defect, which increases the risk of occurrence of operational problems such as breakout, and deteriorates the surface of the slab. JP 63
In No. -10052, the cause of this is that Al in molten steel and flux react with each other to generate grenite (2CaO Al 2 O).
It is analyzed that this is due to the precipitation of 3 SiO 2 ).
【0004】そして、その問題についての解決方法とし
て、特開昭63−10052号公報では、CaO及びS
iO2 を主成分として含有する人工スラグ形成用パウダ
ーを用いて少なくとも0.10重量%のAlを含有する
溶鋼を連続鋳造する際に、溶鋼中のAlと該人工スラグ
との反応によりゲーレナイト(Gehlenite)
(2CaO Al2 O3 SiO2 )を鋳造中に析出さ
せないために、(a)塩基度(CaO/SiO2 )=
0.5〜0.8、(b)融点=800〜1000℃、
(c)1300℃における粘性=1.5ポイズ以下とい
う条件を満足するように調整したパウダーを使用するこ
とが提案されている。この方法は、前記の条件を設定す
ることにより、鋳造でAlがフラックスに溶けてきても
CaO/SiO2 があまり高くならず、ゲーレナイトの
領域に入らないようにしたものである。また、別の難鋳
造鋼種である含Zr鋼の連続鋳造に関しては、特開平3
−146245号公報においてフラックスにZrO2 を
含有させたものを使用する連続鋳造法が提案されてい
る。As a solution to the problem, Japanese Unexamined Patent Publication No. Sho 63-10052 discloses CaO and S.
When continuous casting of molten steel containing at least 0.10% by weight of Al using an artificial slag forming powder containing iO 2 as a main component, a reaction between Al in the molten steel and the artificial slag is used to produce Gehlenite. )
To prevent (2CaO Al 2 O 3 SiO 2 ) from precipitating during casting, (a) basicity (CaO / SiO 2 ) =
0.5-0.8, (b) melting point = 800-1000 ° C.,
(C) It has been proposed to use a powder adjusted so as to satisfy the condition that the viscosity at 1300 ° C. = 1.5 poise or less. In this method, by setting the above-mentioned conditions, CaO / SiO 2 does not become so high even when Al is melted in the flux during casting, and the CaO / SiO 2 does not enter the region of the grenite. Further, regarding continuous casting of Zr-containing steel, which is another difficult cast steel type, Japanese Patent Application Laid-Open No. Hei 3
JP-A-146245 proposes a continuous casting method using a flux containing ZrO 2 .
【0005】[0005]
【発明が解決しようとする課題】先に提案された特開昭
63−10052号公報の連続鋳造法は、その技術手段
の内容が、含Al溶鋼との反応でAl2 O3 がフラック
スに入って来ることを前提に、塩基度(CaO/SiO
2 )の低いもの、言い換えればSiO2 の割合が高い組
成のフラックスを用いて、Al2 O3 が入って来ても、
組成が変化したものが融点の高いゲーレナイトの領域に
入らないようにしたものである。しかし、これはAl2
O3 が入って来ることを前提にしていて、組成のかなり
の変化があるものであるから、物性のある程度の変動は
避けられない。このため、連続鋳造中においてフラック
スを使用して形成されるスラグの物性の変動がより少な
くなるようなフラックスを開発することが必要である。
本発明は、少なくとも0.10%のAlを含有する含A
l溶鋼、特に含Alステンレス溶鋼の連続鋳造時におい
て、上記の問題を解決するための連続鋳造用フラックス
及び連続鋳造方法を提供することを目的とするものであ
る。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The continuous casting method disclosed in Japanese Patent Laid-Open No. 63-10052 has the technical means that Al 2 O 3 enters the flux by the reaction with molten aluminum-containing steel. The basicity (CaO / SiO
2 ) is low, in other words, even if Al 2 O 3 comes in using a flux having a composition with a high proportion of SiO 2 ,
The composition is changed so that it does not enter the region of the high melting point of gehlenite. However, this is Al 2
Since it is assumed that O 3 will come in and the composition will change considerably, some variation in physical properties is inevitable. For this reason, it is necessary to develop a flux in which the fluctuations in the physical properties of the slag formed using the flux during continuous casting are reduced.
The present invention is directed to the inclusion of A containing at least 0.10% Al.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a continuous casting flux and a continuous casting method for solving the above problems in continuous casting of molten steel, particularly Al-containing stainless molten steel.
【0006】[0006]
【課題を解決するための手段】本発明は、下記の手段に
よりその課題を解決した。 (1)少なくとも0.10重量%のAlを含有する溶鋼
を連続鋳造するための連続鋳造用フラックスにおいて、
T.C.:1.0〜5.0%,SiO2 :10〜30
%,Al2 O3 :15〜35%,CaO:25〜40
%,Na2 O:5〜15%,F:5〜15%,Li
2 O:0〜5%,その他不可避的不純物としてFe2 O
3 ,MgO等を合計で5%以下を含むことを特徴とする
含Al溶鋼連続鋳造用フラックス。 (2)下記の条件を満足する組成に調整されていること
を特徴とする請求項1記載の含Al溶鋼連続鋳造用フラ
ックス。 CaO/(SiO2 +Al2 O3 )=0.7〜0.9 融点=1000〜1200℃ 1300℃における粘度=2.0ポアズ以下 (3)フラックスを用いて少なくとも0.10重量%の
Alを含有する溶鋼を連続鋳造する方法において、前記
(1)又は(2)項記載の含Al溶鋼連続鋳造用フラッ
クスを用いることを特徴とする含Al溶鋼連続鋳造方
法。The present invention has solved the problem by the following means. (1) In a continuous casting flux for continuously casting molten steel containing at least 0.10% by weight of Al,
T. C. : 1.0~5.0%, SiO 2: 10~30
%, Al 2 O 3 : 15 to 35%, CaO: 25 to 40
%, Na 2 O: 5 to 15%, F: 5 to 15%, Li
2 O: 0 to 5%, Fe 2 O as other unavoidable impurities
A flux for continuous casting of Al-containing molten steel, characterized by containing 3 or less of MgO in total. (2) The flux for continuous casting of Al-containing molten steel according to claim 1, wherein the flux is adjusted to a composition satisfying the following conditions. CaO / a (SiO 2 + Al 2 O 3 ) = 0.7~0.9 mp = 1000 to 1200 ° C. 1300 ° C. Viscosity = 2.0 poises in (3) Al of at least 0.10 weight percent with a flux A continuous casting method for molten aluminum-containing steel, which comprises using the flux for continuous casting molten aluminum-containing steel according to the above (1) or (2) in the method for continuously casting the molten steel contained therein.
【0007】本発明者らは、含Al溶鋼の難鋳造性の原
因であるとされる、溶鋼中のAlとパウダーとが反応し
てゲーレナイトが析出する機構を研究したところ、溶鋼
中のAlとフラックス中のSiO2 が反応してフラック
ス組成が変化することに起因することを見いだした。す
なわち、CaO及びSiO2 を主成分とするフラックス
を、少なくとも0.10重量%のAlを含有する溶鋼を
連続鋳造するに際し、溶鋼中のAlとフラックス中のS
iO2 が(1)式に示す反応を起こすことによって、フ
ラックスの組成が変化する。Alは、強力な酸化物(A
l2 O3 )形成元素である。このため、Alを含む溶鋼
と溶融した前記フラックスとが接触すると、鋼中のAl
とフラックス中のSiO2 とが下記の式によって反応す
る。なお、式中、( )内はスラグ中の成分、〔 〕内
は鋼中の成分を意味する。 3(SiO2 )+4〔Al〕=3〔Si〕+2(Al2 O3 )・・・(1) このような反応が起こると、溶融フラックス中のAl2
O3 が増加し、SiO2 が減少し、フラックスの粘度と
凝固温度が大きく変化する。The inventors of the present invention have studied the mechanism of the reaction of Al in the molten steel with the powder, which is said to be the cause of the difficult casting of molten aluminum-containing steel, and the precipitation of gehlenite. It has been found that SiO 2 in the flux reacts and the flux composition changes. That is, when continuously casting a molten steel containing at least 0.10 wt% of Al with a flux containing CaO and SiO 2 as main components, Al in the molten steel and S in the flux
The composition of the flux changes as iO 2 causes the reaction shown in the formula (1). Al is a strong oxide (A
L 2 O 3 ) forming element. Therefore, when molten steel containing Al contacts with the molten flux, Al in the steel
And SiO 2 in the flux react according to the following equation. In the formula, the value in () means the component in the slag, and the value in [] means the component in the steel. 3 (SiO 2 ) +4 [Al] = 3 [Si] +2 (Al 2 O 3 ) ... (1) When such a reaction occurs, Al 2 in the molten flux
O 3 increases, SiO 2 decreases, and the viscosity and solidification temperature of the flux change significantly.
【0008】これにより、フラックスの物性が変化し、
鋳片の表面品質の悪化及び連続鋳造の操業不良を起こす
ことが判明した。この時、多くのフラックスは、CaO
−SiO2 −Al2 O3 三元系状態図中にて、シュード
ウラストナイト(Pseudowollastonit
e)(CaO・SiO2 )相からゲーレナイト(2Ca
O・Al2 O3 ・SiO2 )相へ組成が変化する(図1
参照)。 図1は、従来のフラックスの鋳造中における組成変化の
例をCaO−Al2 O3 −SiO2 三元状態図中に示し
たものである。図中で、Aは比較例1を、Bは比較例5
のフラックス(表1)の組成変化を示している。またC
は、特開昭63−10052公報のフラックスの組成変
化を示している。この認識を前提として、本発明では、
連続鋳造用フラックスの物性変化を極力抑えるために、
あらかじめゲーレナイト相の組成までAl2 O3 をフラ
ックスに添加しておくことを着想した。これはSiO2
の割合を多くしてゲーレナイト相まで達しないようにす
るという前記の方法とは全く技術の方向を異にしてい
る。しかも、この場合、単に従来のフラックスにAl2
O3 を添加するというだけでは、融点が上昇してモール
ド壁に付着したパウダーリムの肥大化などが起こるの
で、その適正添加量の範囲を定め、かつ他のフラックス
成分の添加により融点を下げ、それらの成分の量の調整
も同時に行う必要がある。これらの点を考慮して、連続
鋳造の進行に伴ってフラックスの物性が変化せず、かつ
融点なども連続鋳造を行うに必要な低い融点が維持され
るような組成をもつ連続鋳造用フラックスを開発した。As a result, the physical properties of the flux change,
It was found that the surface quality of the slab deteriorates and the operation of continuous casting becomes poor. At this time, most of the flux is CaO.
At -SiO 2 -Al 2 O 3 ternary phase diagram in, shoe dough last night (Pseudowollastonit
e) From the (CaO ・ SiO 2 ) phase to the grenenite (2Ca
O · Al 2 O 3 · SiO 2) in composition to the phase change (FIG. 1
reference). FIG. 1 shows an example of a composition change during casting of a conventional flux in a CaO—Al 2 O 3 —SiO 2 ternary phase diagram. In the figure, A is Comparative Example 1 and B is Comparative Example 5.
2 shows the composition change of the flux (Table 1). Also C
Shows the composition change of the flux disclosed in JP-A-63-10052. Based on this recognition, in the present invention,
In order to minimize changes in the physical properties of the flux for continuous casting,
It was conceived that Al 2 O 3 was added to the flux in advance to the composition of the gehlenite phase. This is SiO 2
The direction of the technology is completely different from that of the above-mentioned method in which the proportion of is increased so as not to reach the Gehrenite phase. Moreover, in this case, Al 2
If only O 3 is added, the melting point rises and the powder rim adhering to the mold wall is enlarged, so the appropriate addition amount range is set, and the melting point is lowered by adding other flux components. It is also necessary to adjust the amounts of those components at the same time. In consideration of these points, a flux for continuous casting that has a composition such that the physical properties of the flux do not change with the progress of continuous casting, and the melting point and other low melting points required for continuous casting are maintained. developed.
【0009】すなわち、本発明は、従来のCaO−Si
O2 系フラックスについて予めAl2 O3 が20%程度
添加されており、かつゲーレナイト(2CaO・Al2
O3・SiO2 )相の組成に含まれるように成分を調整
したフラックスとし、さらにLiO2 を数%添加するこ
とにより、融点、粘度を調整し、安定した鋳造をするこ
とができるものである。その他Fなども添加して融点な
どの調整をする。本発明のフラックスは、その目的とす
る特性を得るために、その組成が、T.C.:1.0〜
5.0%,SiO2 :10〜30%,Al2 O3 :15
〜35%,CaO:25〜40%,Na2 O:5〜15
%,F:5〜15%,Li2 O:0〜5%,その他不可
避的不純物としてFe2 O3 ,MgO等を合計で5%以
下を含むものである。That is, the present invention is based on the conventional CaO-Si.
Al 2 O 3 is added to the O 2 -based flux in an amount of about 20% in advance, and it is also used for gehlenite (2CaO · Al 2
(O 3 · SiO 2 ) A flux whose components are adjusted to be contained in the composition of the phase, and by adding a few% of LiO 2 , the melting point and viscosity can be adjusted, and stable casting can be performed. . In addition, F and the like are added to adjust the melting point and the like. The flux of the present invention has a composition of T.O. C. : 1.0 ~
5.0%, SiO 2: 10~30% , Al 2 O 3: 15
~35%, CaO: 25~40%, Na 2 O: 5~15
%, F: 5~15%, Li 2 O: 0~5%, is intended to include more than 5% of Fe 2 O 3, MgO, etc. in total as other unavoidable impurities.
【0010】本発明のフラックスは、好ましくは、その
組成が、T.C.:2.0〜4.0%,SiO2 :18
〜22%,Al2 O3 :17〜21%,CaO:22〜
36%,Na2 O:6〜10%,F:7〜11%,Li
2 O:2〜4%,その他不可避的不純物としてFe2 O
3 ,MgO等を合計で5%以下を含むものであり、より
好ましくは、その組成が、T.C.:3.0〜4.0
%,SiO2 :19〜21%,Al2 O3 :18〜20
%,CaO:31〜35%,Na2 O:7〜9%,F:
8〜10%,Li2 O:2〜4%,その他不可避的不純
物としてFe2 O3 ,MgO等を合計で5%以下を含む
ものである。The flux of the present invention preferably has a composition of T.I. C. : 2.0~4.0%, SiO 2: 18
~22%, Al 2 O 3: 17~21%, CaO: 22~
36%, Na 2 O: 6 to 10%, F: 7 to 11%, Li
2 O: 2 to 4%, Fe 2 O as other unavoidable impurities
3 , containing 5% or less of MgO or the like in total, and more preferably having a composition of T. C. : 3.0 to 4.0
%, SiO 2 : 19 to 21%, Al 2 O 3 : 18 to 20
%, CaO: 31-35%, Na 2 O: 7-9%, F:
8 to 10%, Li 2 O: 2 to 4%, and 5% or less in total of Fe 2 O 3 , MgO and the like as other unavoidable impurities.
【0011】本発明のフラックスは、前記の目的から、
CaO/(SiO2 +Al2 O3 )=0.7〜0.9、
15〜35%のAl2 O3 を含有し、1300℃におけ
る粘度が2.0ポアズ以下になるよう、他のフラックス
成分で調整されているものであることが望ましい。そし
て、連続鋳造を行うことから、融点が1000〜120
0℃の範囲にあることが必要である。本発明のフラック
スを用いた場合における鋳造中のその組成の変化を図1
でみると、Dは実施例の「発明例No.6」の場合に該
当するものであって、その融点の変化が小さいことがわ
かる。The flux of the present invention has the following objects.
CaO / (SiO 2 + Al 2 O 3 ) = 0.7 to 0.9,
It is preferable that the composition contains 15 to 35% of Al 2 O 3 and is adjusted with other flux components so that the viscosity at 1300 ° C. is 2.0 poise or less. Since the continuous casting is performed, the melting point is 1000 to 120.
It must be in the range of 0 ° C. FIG. 1 shows changes in the composition during casting when the flux of the present invention is used.
From the above, it is understood that D corresponds to the case of "Invention Example No. 6" of the example, and the change of the melting point is small.
【0012】[0012]
【発明の実施の形態】以下、本発明のフラックスについ
て、各成分の作用効果と含有量の範囲の限定理由を説明
する。 (T.C.)C(炭素)は、フラックスの骨材として、
すなわち溶融速度をコントロールする機能を有する。
1.0%未満であると、溶融速度が早くなりすぎ、鋳型
−鋳片間への流入量が過多となる。5.0%超であると
溶融速度が遅くなり、流入量が過少となる。BEST MODE FOR CARRYING OUT THE INVENTION The effects of each component and the reason for limiting the content range of the flux of the present invention will be described below. (TC) C (carbon), as an aggregate of the flux,
That is, it has a function of controlling the melting rate.
If it is less than 1.0%, the melting rate becomes too fast, and the amount of inflow between the mold and the slab becomes excessive. If it exceeds 5.0%, the melting rate becomes slow and the inflow becomes too small.
【0013】(Al2 O3 ,CaO,SiO2 )通常の
フラックスは、CaO,SiO2 が主成分であるが、本
発明のフラックスの最大の特徴は、予めAl2 O3 が添
加されていることである。このように予め添加するAl
2 O3 の量が適当であれば、前記(1)の反応が殆ど起
こらず、溶融フラックスの組成の変化が少ない。ここで
添加されるAl2 O3 の量は、CaO−SiO2 −Al
2 O3 三元系状態図により決定される。通常の多くのフ
ラックスは、Al含有量が多いほど(1)の反応によっ
てシュードウラストナイト相からゲーレナイト相へと組
成が変化する。この時、共晶線上を通過するためフラッ
クスの物性の変化が大きい。従って、予めゲーレナイト
相の組成までAl2 O3 を添加して、フラックスの相変
化、すなわち物性変化を起こさせないのである。(Al 2 O 3 , CaO, SiO 2 ) The usual flux is mainly composed of CaO and SiO 2, but the greatest feature of the flux of the present invention is that Al 2 O 3 is added in advance. That is. Al added in advance in this way
If the amount of 2 O 3 is appropriate, the reaction of the above (1) hardly occurs and the composition of the molten flux changes little. The amount of Al 2 O 3 added here is CaO-SiO 2 -Al.
2 O 3 Determined by the ternary phase diagram. The composition of many ordinary fluxes changes from the pseudowollastonite phase to the gehlenite phase due to the reaction (1) as the Al content increases. At this time, the physical properties of the flux change greatly because it passes over the eutectic line. Therefore, Al 2 O 3 is added to the composition of the gehlenite phase in advance to prevent the phase change of the flux, that is, the change of the physical properties.
【0014】また、ノロカミのような障害を防止するた
めの指標としてフラックスのCaO/SiO2 を1.0
未満とするのは公知の事実であるが、本発明のフラック
スのようにAl2 O3 が多量に存在する場合はCaO/
SiO2 の比によって決まるものではなく、これは指標
とならない。 そこで、本発明ではその指標としてCa
O/(SiO2 +Al2 O3 )を用い、これを1.0未
満となるように配合するのである。なお、SiO2 の含
有量は10〜30%、Al2 O3 は15〜35%、Ca
Oは25〜40%、そしてCaO/(SiO2 +Al2
O3 )は0.7〜0.9程度にするのが望ましい。Further, the flux CaO / SiO 2 is 1.0 as an index for preventing obstacles such as shavings.
It is a known fact that the amount is less than CaO / CaO / when a large amount of Al 2 O 3 is present as in the flux of the present invention.
It is not determined by the ratio of SiO 2 , and this is not an index. Therefore, in the present invention, Ca is used as the index.
O / (SiO 2 + Al 2 O 3 ) is used and blended so as to be less than 1.0. The content of SiO 2 is 10 to 30%, Al 2 O 3 is 15 to 35%, and Ca
O is 25-40%, and CaO / (SiO 2 + Al 2
It is desirable that O 3 ) be about 0.7 to 0.9.
【0015】(Na2 O,Li2 O,F)上記の組成の
みでは、高融点、高粘度になりすぎ、鋳型−鋳片(ない
しはフラックスが凝固して形成する殻)間のフラックス
の流入を阻害する。そこでこれらのフラックス成分を添
加することにより、融点及び粘度を調整する。この場合
Na2 Oは5〜15%,Li2 Oは0〜5%,Fは5〜
15%程度にあることが望ましい。 (不可避的不純物)このようなフラックスにはFe2 O
3 やMgOなどの不純物が不可避的に混入してくる。こ
れらの不純物は少ない程よいが、合計で5%以下に抑え
るようにする。(Na 2 O, Li 2 O, F) With only the above composition, the melting point and the viscosity become too high, and the flux inflow between the mold and the cast piece (or the shell formed by the solidification of the flux) is prevented. Inhibit. Therefore, the melting point and the viscosity are adjusted by adding these flux components. In this case, Na 2 O is 5 to 15%, Li 2 O is 0 to 5%, and F is 5 to 5%.
It is preferably about 15%. (Inevitable impurities) Fe 2 O for such flux
Impurities such as 3 and MgO are inevitably mixed in. The less these impurities are, the better, but the total amount should be suppressed to 5% or less.
【0016】[0016]
【実施例】以下実施例により本発明を具体的に説明す
る。ただし、本発明はこれらに限定されるものではな
い。第1〜2表に示す組成のAl溶鋼を、同じく第1〜
2表に示す組成のフラックスを使用して連続鋳造用の鋳
型を用いて連続鋳造した。鋳造温度は1500〜155
0℃であった。本発明による例が発明例1〜7であり、
比較として比較例8〜12を行った(便宜上試料番号N
o.1〜12に対応した続き番号とする)。発明例1〜
7においてはいずれも鋳造中にトラブルがなく、安定操
業が行えたが、比較例8〜12では鋳造速度が低下する
などがみられた。各例における鋳造結果及びスラブの表
面研磨量indexを第1表及び第2表に示した。The present invention will be described in detail with reference to the following examples. However, the present invention is not limited to these. Al molten steel having the composition shown in Tables 1 and 2 is also
Using the flux having the composition shown in Table 2, continuous casting was performed using a casting mold for continuous casting. Casting temperature is 1500-155
It was 0 ° C. Examples according to the present invention are Invention Examples 1 to 7,
Comparative examples 8 to 12 were carried out for comparison (for convenience, sample number N
o. Sequential numbers corresponding to 1 to 12). Invention Example 1
In No. 7, there was no trouble during casting and stable operation could be performed, but in Comparative Examples 8 to 12, it was observed that the casting speed decreased. The casting results and the slab surface polishing amount index in each example are shown in Tables 1 and 2.
【0017】[0017]
【表1】 [Table 1]
【0018】[0018]
【表2】 [Table 2]
【0019】また、発明例1及び比較例8の鋳造中にお
いては、20分毎にフラックスをサンプリングし、それ
を分析した。図2に発明例1のフラックスの組成変化を
示し、図3に比較例8のフラックスの組成変化を示す。
発明例1では組成変化が非常に小さくて良好な結果であ
ったのに対し、比較例8では著しい組成変化が認められ
る。さらに、鋳造して得られるスラブについては、その
表面に疵が有る場合にはその疵を無くすために、その表
面を削って疵を取る加工がなされるが、発明例1及び比
較例8について行った疵取り量を図4に示す。発明例1
の場合比較例8のスラブに比べて約1/7の疵取り量で
あり、良好な結果が得られた。Further, during casting of Inventive Example 1 and Comparative Example 8, flux was sampled every 20 minutes and analyzed. FIG. 2 shows the composition change of the flux of Inventive Example 1, and FIG. 3 shows the composition change of the flux of Comparative Example 8.
In Inventive Example 1, the composition change was very small, which was a good result, whereas in Comparative Example 8, a remarkable composition change was observed. Further, in the case of a slab obtained by casting, in the case where the surface has a flaw, in order to eliminate the flaw, the surface is shaved to remove the flaw, but the invention example 1 and the comparative example 8 are performed. The scratch removal amount is shown in FIG. Invention Example 1
In the case of, the flaw removal amount was about 1/7 of that of the slab of Comparative Example 8, and a good result was obtained.
【0020】[0020]
【発明の効果】本発明によれば、含Al溶鋼の連続鋳造
において、フラックス組成の変化がすくなくなり、安定
な操業が可能となった。連続鋳造により得られるスラブ
は表面性状が良好なものが得られるので、疵取量の減少
に伴って生産コストが低減した。EFFECTS OF THE INVENTION According to the present invention, in continuous casting of Al-containing molten steel, changes in the flux composition are reduced and stable operation is possible. Since the slab obtained by continuous casting has good surface properties, the production cost decreased as the flaw removal amount decreased.
【図1】本発明のフラックス等の組成及び鋳造中の組成
変化を表わしたCaO−SiO2 −Al2 O3 三元系状
態図を示す。FIG. 1 is a CaO—SiO 2 —Al 2 O 3 ternary phase diagram showing the composition of the flux etc. of the present invention and the composition change during casting.
【図2】本発明のフラックスの発明例1の鋳造時間に伴
う組成変化を表わすグラフを示す。FIG. 2 is a graph showing a change in composition with the casting time of Inventive Example 1 of the flux of the present invention.
【図3】比較例8のフラックスの鋳造時間に伴う組成変
化を表わすグラフを示す。FIG. 3 is a graph showing the composition change of the flux of Comparative Example 8 with casting time.
【図4】本発明の発明例1及び比較例8におけるスラブ
表面の疵取り量の差を表した図を示す。FIG. 4 is a diagram showing a difference in the amount of flaw removal on the slab surface in Inventive Example 1 of the present invention and Comparative Example 8.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成8年3月25日[Submission date] March 25, 1996
【手続補正1】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】0008[Correction target item name] 0008
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【0008】これにより、フラックスの物性が変化し、
鋳片の表面品質の悪化及び連続鋳造の操業不良を起こす
ことが判明した。この時、多くのフラックスは、CaO
−SiO2−Al2O3三元系状態図中にて、シュード
ウラストナイト(Pseudowollastonit
e)(CaO・SiO2)相からゲーレナイト(2Ca
O−Al2O3・SiO2)相へ組成が変化する(図1
参照)。 図1は、従来のフラックスの鋳造中における組成変化の
例をCaO−Al2O3−SiO2三元状態図中に示し
たものである。図中で、Aは比較例8を、Bは比較例1
2のフラックス(第2表)の組成変化を示している。ま
たCは、特開昭63−10052公報のフラックスの組
成変化を示している。この認識を前提として、本発明で
は、連続鋳造用フラックスの物性変化を極力抑えるため
に、あらかじめゲーレナイト相の組成までAl2O3を
フラックスに添加しておくことを着想した。これはSi
O2の割合を多くしてゲーレナイト相まで達しないよう
にするという前記の方法とは全く技術の方向を異にして
いる。しかも、この場合、単に従来のフラックスにAl
2O3を添加するというだけでは、融点が上昇してモー
ルド壁に付着したパウダーリムの肥大化などが起こるの
で、その適正添加量の範囲を定め、かつ他のフラックス
成分の添加により融点を下げ、それらの成分の量の調整
も同時に行う必要がある。これらの点を考慮して、連続
鋳造の進行に伴ってフラックスの物性が変化せず、かつ
融点なども連続鋳造を行うに必要な低い融点が維持され
るような組成をもつ連続鋳造用フラックスを開発した。As a result, the physical properties of the flux change,
It was found that the surface quality of the slab deteriorates and the operation of continuous casting becomes poor. At this time, most of the flux is CaO.
At -SiO 2 -Al 2 O 3 ternary phase diagram in, shoe dough last night (Pseudowollastonit
e) From the (CaO · SiO 2 ) phase to the grenite (2Ca
O-Al 2 O 3 · SiO 2) in composition to the phase change (FIG. 1
reference). FIG. 1 shows an example of a composition change in a conventional flux during casting in a CaO—Al 2 O 3 —SiO 2 ternary phase diagram. In the figure, A is Comparative Example 8 and B is Comparative Example 1.
2 shows the compositional change of flux 2 ( Table 2 ). Further, C indicates the composition change of the flux disclosed in JP-A-63-10052. Based on this recognition, in the present invention, in order to suppress the physical property change of the flux for continuous casting as much as possible, it was conceived that Al 2 O 3 was added to the flux in advance to the composition of the gehlenite phase. This is Si
The direction of the technology is completely different from that of the above method in which the proportion of O 2 is increased so as not to reach the gehlenite phase. Moreover, in this case, Al is simply added to the conventional flux.
If only 2 O 3 is added, the melting point rises and the powder rim adhering to the mold wall may become enlarged. Therefore, the appropriate addition amount range should be set and the melting point should be lowered by adding other flux components. , It is necessary to adjust the amounts of those components at the same time. In consideration of these points, a flux for continuous casting that has a composition such that the physical properties of the flux do not change with the progress of continuous casting, and the melting point and other low melting points required for continuous casting are maintained. developed.
Claims (3)
する溶鋼を連続鋳造するための連続鋳造用フラックスに
おいて、T.C.:1.0〜5.0%,SiO2 :10
〜30%,Al2 O3 :15〜35%,CaO:25〜
40%,Na2 O:5〜15%,F:5〜15%,Li
2 O:0〜5%,その他不可避的不純物としてFe2 O
3 ,MgO等を合計で5%以下を含むことを特徴とする
含Al溶鋼連続鋳造用フラックス。1. A continuous casting flux for the continuous casting of molten steel containing at least 0.10% by weight Al. C. : 1.0 to 5.0%, SiO 2 : 10
~30%, Al 2 O 3: 15~35%, CaO: 25~
40%, Na 2 O: 5 to 15%, F: 5 to 15%, Li
2 O: 0 to 5%, Fe 2 O as other unavoidable impurities
A flux for continuous casting of Al-containing molten steel, characterized by containing 3 or less of MgO in total.
いることを特徴とする請求項1記載の含Al溶鋼連続鋳
造用フラックス。 CaO/(SiO2 +Al2 O3 )=0.7〜0.9 融点=1000〜1200℃ 1300℃における粘度=2.0ポアズ以下2. The flux for continuous casting of Al-containing molten steel according to claim 1, wherein the flux is adjusted to a composition satisfying the following conditions. CaO / (SiO 2 + Al 2 O 3 ) = 0.7 to 0.9 Melting point = 1000 to 1200 ° C. Viscosity at 1300 ° C. = 2.0 poise or less
重量%のAlを含有する溶鋼を連続鋳造する方法におい
て、請求項1又は2記載の含Al溶鋼連続鋳造用フラッ
クスを用いることを特徴とする含Al溶鋼連続鋳造方
法。3. At least 0.10 with flux.
A continuous casting method for molten aluminum containing steel, characterized in that a flux for continuous casting molten aluminum containing steel according to claim 1 or 2 is used in the method for continuously casting molten steel containing wt% Al.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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JP26091295A JP2964452B2 (en) | 1995-09-14 | 1995-09-14 | Flux for continuous casting of molten steel containing A1 and continuous casting method |
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Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP26091295A JP2964452B2 (en) | 1995-09-14 | 1995-09-14 | Flux for continuous casting of molten steel containing A1 and continuous casting method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0976049A true JPH0976049A (en) | 1997-03-25 |
JP2964452B2 JP2964452B2 (en) | 1999-10-18 |
Family
ID=17354487
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JP26091295A Expired - Lifetime JP2964452B2 (en) | 1995-09-14 | 1995-09-14 | Flux for continuous casting of molten steel containing A1 and continuous casting method |
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