JPH10216907A - Mold powder for continuous casting - Google Patents
Mold powder for continuous castingInfo
- Publication number
- JPH10216907A JPH10216907A JP3150797A JP3150797A JPH10216907A JP H10216907 A JPH10216907 A JP H10216907A JP 3150797 A JP3150797 A JP 3150797A JP 3150797 A JP3150797 A JP 3150797A JP H10216907 A JPH10216907 A JP H10216907A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- mold
- group
- oxides
- range
- 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.)
- Granted
Links
- 239000000843 powder Substances 0.000 title claims abstract description 51
- 238000009749 continuous casting Methods 0.000 title claims abstract description 13
- 230000000737 periodic effect Effects 0.000 claims abstract description 11
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 9
- 229910018068 Li 2 O Inorganic materials 0.000 claims description 5
- 229910052708 sodium Inorganic materials 0.000 claims description 4
- 229910052792 caesium Inorganic materials 0.000 claims description 3
- 229910052701 rubidium Inorganic materials 0.000 claims description 3
- 239000013078 crystal Substances 0.000 abstract description 18
- 238000002425 crystallisation Methods 0.000 abstract description 9
- 230000008025 crystallization Effects 0.000 abstract description 9
- 238000010583 slow cooling Methods 0.000 abstract description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract 2
- 229910004865 K2 O Inorganic materials 0.000 abstract 1
- 229910011763 Li2 O Inorganic materials 0.000 abstract 1
- 229910004742 Na2 O Inorganic materials 0.000 abstract 1
- 229910052681 coesite Inorganic materials 0.000 abstract 1
- 229910052906 cristobalite Inorganic materials 0.000 abstract 1
- 239000000377 silicon dioxide Substances 0.000 abstract 1
- 235000012239 silicon dioxide Nutrition 0.000 abstract 1
- 229910052682 stishovite Inorganic materials 0.000 abstract 1
- 229910052905 tridymite Inorganic materials 0.000 abstract 1
- 229910000831 Steel Inorganic materials 0.000 description 11
- 239000010959 steel Substances 0.000 description 11
- 230000004907 flux Effects 0.000 description 9
- 101100348084 Drosophila melanogaster CDase gene Proteins 0.000 description 8
- 239000011521 glass Substances 0.000 description 7
- 230000008018 melting Effects 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 4
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- 229910004261 CaF 2 Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000005499 meniscus Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 241001669680 Dormitator maculatus Species 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Landscapes
- Continuous Casting (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、鋼の連続鋳造に用
いられるモールドパウダーに関する。TECHNICAL FIELD The present invention relates to a mold powder used for continuous casting of steel.
【０００２】[0002]
【従来の技術】鋼の連続鋳造において、モールドパウダ
ーは溶鋼の上面にあっては溶鋼の酸化防止、保温、浮上
介在物の吸収という機能を有し、また鋳型（以下、モー
ルドともいう）と鋳片との間に流入し、潤滑および鋼の
抜熱制御を行っている。2. Description of the Related Art In continuous casting of steel, mold powder has a function of preventing oxidation of molten steel, keeping heat, absorbing floating inclusions on the upper surface of the molten steel, and a mold powder (hereinafter also referred to as a mold). It flows between the pieces and controls lubrication and heat removal of steel.
【０００３】鋼の中で、中炭素鋼と呼ばれる炭素含有量
が０．０８〜０．１８％の亜包晶鋼領域の鋼において
は、凝固時のδ→γ変態により体積収縮が大きく、不均
一凝固しやすいため、鋳片に縦割れが発生しやすい。こ
の縦割れ発生は鋳型内の熱流束と相関があり、熱流束を
低下させることで、その発生を抑制することが可能であ
る。したがって、使用するパウダーは緩冷却可能な特性
を有することが望ましい。[0003] Among the steels, in the steel in the subperitectic steel region having a carbon content of 0.08 to 0.18%, which is called a medium carbon steel, the volume shrinkage is large due to the δ → γ transformation at the time of solidification. Since it is easy to solidify uniformly, vertical cracks are easily generated in the slab. The occurrence of the vertical cracks has a correlation with the heat flux in the mold, and it is possible to suppress the occurrence by reducing the heat flux. Therefore, it is desirable that the powder to be used has characteristics that allow for slow cooling.
【０００４】中炭素鋼用モールドパウダーに関して、市
川らは品川技報Ｎｏ．２３に、パウダーの塩基度（Ｃａ
Ｏ／ＳｉＯ2）を上げることによって、凝固点を上昇さ
せ、かつ凝固の際に結晶化を促進させることによって、
モールドと鋳片（凝固シェル）との間に流入する溶融ス
ラグのうち、モールド側に固着した凝固層内に空隙を生
じさせ、凝固層の見かけの熱伝導率を低下させ、鋳片の
割れを防止することができるとしている。Regarding mold powder for medium carbon steel, Ichikawa et al. 23, the basicity of the powder (Ca
O / SiO 2 ) to increase the freezing point and to promote crystallization during solidification,
Of the molten slag flowing between the mold and the slab (solidified shell), voids are created in the solidified layer fixed to the mold side, reducing the apparent thermal conductivity of the solidified layer and causing cracks in the slab. It can be prevented.
【０００５】また、特開平３−１９３２４８号公報で
は、市川らと同じく、モールドに固着した凝固層中の熱
伝導率を下げるという観点から、パウダーの凝固点を高
め、かつ溶融スラグをガラス化させずに結晶化させるた
め、パウダーの１成分として周期律表IIIＡ族およびIV
族の元素の酸化物を少なくとも１種添加することが望ま
しいとし、これらの１種または２種以上を０．０１〜１
５％含有することが示されている。In Japanese Patent Application Laid-Open No. 3-193248, similarly to Ichikawa et al., From the viewpoint of lowering the thermal conductivity in the solidified layer fixed to the mold, the solidification point of the powder is increased and the molten slag is not vitrified. As a component of the powder, group IIIA and IV of the periodic table
It is desirable to add at least one oxide of an element belonging to the group III.
It is shown to contain 5%.
【０００６】[0006]
【発明が解決しようとする課題】以上の従来技術におけ
るパウダーは、鋳型に接触している凝固層中の熱抵抗を
増大させることにより、鋳型内緩冷却化を図ったもので
あり、一定の成果を挙げてはいるが、さらに鋳片品質を
向上させるために、さらなる緩冷却化が望まれている。SUMMARY OF THE INVENTION The above-mentioned prior art powder is intended to achieve slow cooling in the mold by increasing the thermal resistance in the solidified layer in contact with the mold. However, in order to further improve the slab quality, further slow cooling is desired.
【０００７】本発明は、かかる事情に鑑みてなされたも
のであって、鋳型内を従来よりも一層緩冷却化すること
ができる連続鋳造用モールドパウダーを提供することを
目的とする。The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mold powder for continuous casting capable of cooling the inside of a mold more slowly than before.
【０００８】[0008]
【課題を解決するための手段】従来技術におけるモール
ドパウダーは、鋳型に接触している凝固層を厚くした
り、その中に気孔を設けることで、凝固層中の熱抵抗を
増大させることにより、鋳型内緩冷却化を図ったもので
ある。The mold powder in the prior art is to increase the thermal resistance in the solidified layer by thickening the solidified layer in contact with the mold or by providing pores in the solidified layer. This is to achieve slow cooling in the mold.
【０００９】しかしながら、本発明者らが種々検討した
結果、鋳型内の熱流束に影響を及ぼす最大の因子は、鋳
型−凝固層間の隙間（エアーギャップ）であり、この界
面の熱抵抗を増大させることにより、鋳型内を大幅に緩
冷却化することができることが判明した。However, as a result of various studies by the present inventors, the largest factor affecting the heat flux in the mold is a gap (air gap) between the mold and the solidified layer, which increases the thermal resistance at this interface. As a result, it has been found that the inside of the mold can be cooled significantly.
【００１０】パウダーがスラグ化し鋳型側に固着して形
成される固着層は、一般には面積率で５０〜７０％の結
晶相と、その粒間に存在するガラス相とで構成されてい
るが、本発明者が界面熱抵抗とこの固着相組織との関係
を調査したところ、結晶化しやすいもの、すなわち結晶
相が多くガラス相が少ないものほど界面熱抵抗が増大
し、緩冷却されることが判明した。The fixing layer formed by slagging the powder and fixing to the mold side is generally composed of a crystal phase having an area ratio of 50 to 70% and a glass phase existing between the grains. The present inventor has investigated the relationship between the interfacial thermal resistance and the structure of the fixed phase, and found that those that easily crystallize, that is, those having a large number of crystal phases and a small number of glass phases, have increased interfacial thermal resistance and are gradually cooled. did.
【００１１】しかしながら、このようなパウダーにおい
ては、その軟化温度が高く、溶融速度が遅くなり、ペア
生成の増大、パウダー流れ込み不足等、溶融特性を満足
させることができず、特に高速鋳造においてパウダーと
しての役割を果たすことはできない。However, in such powders, the softening temperature is high, the melting rate is low, and the melting characteristics cannot be satisfied, such as increased pair formation and insufficient powder flow. Cannot play a role.
【００１２】これは、一般的にはパウダーを溶融して冷
却した際に生じる結晶相は、カスピダイン（３ＣａＯ・
２ＳｉＯ2・ＣａＦ2）という融点の高い物質であり、パ
ウダー中においてその量が増大する高塩基度（ＣａＯ／
ＳｉＯ2＝１．４〜１．６）の条件下では、軟化温度が
高くなるためであると考えられる。[0012] Generally, the crystal phase generated when the powder is melted and cooled is caspidyne (3CaO.
2SiO 2 · CaF 2 ), which has a high melting point and a high basicity (CaO /
It is considered that under the condition of SiO 2 = 1.4 to 1.6), the softening temperature becomes high.
【００１３】しかしながら、本発明者らがさらに検討を
重ねた結果、塩基度（ＣａＯ／ＳｉＯ2）が１．６以上
では、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、Ｒｂ2Ｏ、Ｃｓ2Ｏ等
の周期律表ＩＡ族に属する元素の酸化物を所定量以上含
有させることで、カスピダインとは異なる結晶が生じ、
そして、これら酸化物の２種類以上を複合化すること
で、軟化温度を最適化し、かつ、高い結晶化率を維持す
れば、界面熱抵抗を増大させることができ、その結果鋳
型内を緩冷却にすることができ、鋳片品質が著しく向上
することを見出した。However, as a result of further studies by the present inventors, when the basicity (CaO / SiO 2 ) is 1.6 or more, Li 2 O, Na 2 O, K 2 O, Rb 2 O, Cs 2 By containing a predetermined amount or more of an oxide of an element belonging to Group IA of the periodic table such as O, a crystal different from caspidyne is produced,
By optimizing the softening temperature and maintaining a high crystallization rate by compounding two or more of these oxides, the interfacial thermal resistance can be increased, and as a result, the inside of the mold is slowly cooled. And found that the slab quality was significantly improved.
【００１４】本発明は、このような知見に基づいてなさ
れたものであり、塩基度（ＣａＯ*／ＳｉＯ2）が１．６
〜２．５の範囲であり、周期律表ＩＡ族に属する元素の
酸化物を２種類以上、以下の（１）式の範囲内で含有
し、かつＦを５〜１５重量％の範囲で含有することを特
徴とする連続鋳造用モールドパウダーを提供するもので
ある。 ０．１３＜（ＩＡ族酸化物の合計のモル数）／（Ｃａのモル数）＜０．６ ……（１） ただし、塩基度のＣａＯ*はパウダー中のＣａのモル数
からＣａＯに換算した値である。The present invention has been made based on such findings, and has a basicity (CaO * / SiO 2 ) of 1.6.
２．５2.5, containing two or more oxides of elements belonging to Group IA of the periodic table in the range of the following formula (1), and containing F in a range of 5 to 15% by weight. The present invention provides a mold powder for continuous casting. 0.13 <(total number of moles of group IA oxide) / (number of moles of Ca) <0.6 (1) However, the basicity of CaO * is converted into CaO from the number of moles of Ca in the powder. Value.
【００１５】この場合に、前記周期律表ＩＡ族に属する
元素の酸化物としては、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、Ｒ
ｂ2Ｏ、Ｃｓ2Ｏが例示され、これらから選択されたもの
を用いることができる。また、Ａｌ、Ｍｇ、Ｓｒ、Ｂ
ａ、Ｃｒ、Ｍｎ、Ｆｅの酸化物を合計で０．３〜１０重
量％含むことが好ましい。In this case, the oxides of the elements belonging to Group IA of the periodic table include Li 2 O, Na 2 O, K 2 O, R
b 2 O, Cs 2 O is exemplified, there can be used those selected from these. Al, Mg, Sr, B
It is preferable to contain a total of 0.3 to 10% by weight of oxides of a, Cr, Mn, and Fe.
【００１６】[0016]
【発明の実施の形態】鋳型内の緩冷却化のためには、結
晶化しやすいパウダーを用いることが効果的であること
が経験的に知られている。そして、その結晶化と熱流束
との相関を検討した結果、熱流束を支配する最大の因子
は、鋳型とパウダーフィルム層間の界面熱抵抗であるこ
とが判明した。DESCRIPTION OF THE PREFERRED EMBODIMENTS It has been empirically known that it is effective to use a powder which is easy to crystallize for slow cooling in a mold. As a result of examining the correlation between the crystallization and the heat flux, it was found that the largest factor controlling the heat flux was the interfacial thermal resistance between the mold and the powder film layer.
【００１７】この界面熱抵抗は、パウダーフィルムの鋳
型側表面の凹凸により決定される。本発明者が種々検討
を行った結果、パウダーフィルムの結晶化によりその凹
凸が生じること、パウダーの組成によりその凹凸の大き
さが異なることが見出された。そして、その凹凸の大き
さは、固着層中の結晶化比率に依存することが確認され
た。This interfacial thermal resistance is determined by the unevenness of the surface of the powder film on the mold side. As a result of various studies conducted by the present inventors, it was found that the irregularities are generated by crystallization of the powder film, and that the size of the irregularities differs depending on the composition of the powder. And it was confirmed that the size of the unevenness depends on the crystallization ratio in the fixed layer.
【００１８】中炭素鋼に用いられる塩基度が１．１〜
１．５のパウダーを使用した場合、固着層を電子顕微鏡
により観察すると、面積率で５０〜７０％の結晶相と、
その粒間に存在するガラス相とにより構成されているこ
とが確認される。一般には、この結晶はカスピダイン
（３ＣａＯ・２ＳｉＯ2・ＣａＦ2）と呼ばれる鉱物相か
らなり、粒間にあるガラスはＳｉＯ2、Ａｌ2Ｏ3、Ｎａ2
Ｏ、Ｌｉ2Ｏ、ＣａＯ等の酸化物からなる。The basicity used for medium carbon steel is 1.1 to
When the powder of 1.5 is used, when the fixing layer is observed with an electron microscope, a crystal phase having an area ratio of 50 to 70%,
It is confirmed that it is constituted by the glass phase existing between the grains. In general, the crystal consists of mineral phases called Kasupidain (3CaO · 2SiO 2 · CaF 2 ), glass present between grains SiO 2, Al 2 O 3, Na 2
It is made of an oxide such as O, Li 2 O, and CaO.
【００１９】塩基度を上昇させてこの固着層を９０％以
上結晶化することにより、上記パウダーフィルムの鋳型
側表面の凹凸が２倍以上にもなり、界面熱抵抗を高くで
きることが確認されたが、パウダー中のカスピダイン結
晶はその融点が約１４７０℃とかなり高く、この結晶相
を単純に増加させた場合、軟化温度等パウダーに必要な
溶融特性を満足させることができない。It has been confirmed that by increasing the basicity and crystallizing the fixing layer by 90% or more, the irregularities on the mold-side surface of the powder film become twice or more and the interfacial thermal resistance can be increased. The melting point of the caspidyne crystal in the powder is as high as about 1470 ° C., and if the crystal phase is simply increased, the melting properties required for the powder, such as the softening temperature, cannot be satisfied.
【００２０】この点に鑑み、本発明者が種々検討した結
果、パウダーの塩基度（ＣａＯ*／ＳｉＯ2）が１．６〜
２．５の範囲で、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、Ｒｂ2Ｏ、
Ｃｓ2Ｏ等の周期律ＩＡ族に属する元素の酸化物を２種
類以上、一定範囲で添加することにより、カスピダイン
ではない結晶相を析出させることのできるパウダーとす
ることができることを見出した。これにより得られる結
晶相は、ＬｉＣａ2ＦＳｉＯ4、ＮａＣａ2ＦＳｉＯ4等の
式、またはそれに近い化学量論組成を有するものであ
る。つまり、これらはカスピダインとＩＡ族元素の酸化
物とが１：１で組み合わされた結晶となっている。すな
わち、従来粒間のガラス相側に多く存在していたＩＡ族
元素の酸化物を結晶相として一定量取り込むことがで
き、結晶化率が増大し、界面熱抵抗を増加させることが
容易となった。In view of this point, as a result of various studies by the present inventors, the basicity (CaO * / SiO 2 ) of the powder was 1.6 to
In the range of 2.5, Li 2 O, Na 2 O, K 2 O, Rb 2 O,
It has been found that a powder capable of precipitating a crystal phase other than caspidyne can be obtained by adding two or more oxides of an element belonging to the periodic group IA such as Cs 2 O in a certain range. The resulting crystal phase has a formula such as LiCa 2 FSiO 4 , NaCa 2 FSiO 4 , or a stoichiometric composition close thereto. That is, these are crystals in which cuspidine and an oxide of a Group IA element are combined at a ratio of 1: 1. That is, it is possible to take in a certain amount of the oxide of the IA group element, which was conventionally present on the glass phase side between the grains, as a crystal phase, thereby increasing the crystallization rate and easily increasing the interfacial thermal resistance. Was.
【００２１】また、これらの結晶はカスピダインよりも
融点が低い上、添加するＩＡ族元素の酸化物の組み合わ
せにより、複数の結晶を析出させることが可能である。
このように複数の結晶を析出させることにより、軟化温
度を調節することができるため、結晶化率が高くても軟
化温度が低いパウダーとすることが可能となり、高界面
熱抵抗で鋳型内熱流束が低く、大幅な鋳型内緩冷却化が
実現され、鋳片の割れ防止に絶大な効果を有するモール
ドパウダーを得ることが可能となる。なお、塩基度のＣ
ａＯ*はパウダー中に含まれるＣａ中のモル数からＣａ
Ｏに換算した値である。These crystals have a melting point lower than that of cuspidine, and a plurality of crystals can be precipitated by a combination of an oxide of a Group IA element to be added.
Since the softening temperature can be adjusted by precipitating a plurality of crystals in this manner, it is possible to obtain a powder having a low softening temperature even if the crystallization ratio is high, and the heat flux in the mold with high interfacial thermal resistance. Therefore, it is possible to obtain a mold powder having a remarkable effect in preventing cracks of a slab by significantly reducing cooling in a mold. The basicity C
aO * is calculated from the number of moles in Ca contained in the powder.
It is a value converted to O.
【００２２】本発明に係るモールドパウダーは、その塩
基度（ＣａＯ*／ＳｉＯ2）が１．６〜２．５の範囲であ
り、周期律表ＩＡ族に属する元素の酸化物を２種類以
上、以下の（１）式の範囲内で含有し、かつＦを５〜１
５重量％の範囲で含有する。The mold powder according to the present invention has a basicity (CaO * / SiO 2 ) in the range of 1.6 to 2.5, and contains two or more oxides of elements belonging to Group IA of the periodic table. It is contained within the range of the following formula (1), and F is 5 to 1
It is contained in the range of 5% by weight.
【００２３】ここで、塩基度（ＣａＯ*／ＳｉＯ2）の値
を１．６〜２．５の範囲としたのは、この値が１．６未
満であると、結晶相がカスピダインとなって高界面熱抵
抗の発現には限界があり、一方２．５を超えると、ＩＡ
族元素の酸化物をどのように組み合わせても軟化温度が
１２００℃以上の高温となり、パウダーとしての機能を
持つことができないからである。Here, the value of the basicity (CaO * / SiO 2 ) is set in the range of 1.6 to 2.5. If the value is less than 1.6, the crystal phase becomes caspidyne. There is a limit to the development of high interfacial thermal resistance, while if it exceeds 2.5, IA
This is because the softening temperature becomes as high as 1200 ° C. or more and the powder cannot function as a powder regardless of the combination of the oxides of group elements.
【００２４】また、周期律表ＩＡ族に属する元素の酸化
物を２種類以上含有させることとしたのは、１種類では
軟化温度を有効に低減させることができないからであ
る。これらは（１）式の範囲内で含有する。 ０．１３＜（ＩＡ族酸化物の合計のモル数）／（Ｃａのモル数）＜０．６ ……（１） これは、（ＩＡ族酸化物の合計のモル数）／（Ｃａのモ
ル数）の値が０．１３未満の場合にはカスピダインがか
なりの割合で生じ、軟化温度も高く、パウダーとしての
機能を持たず、一方この値が０．６を超えるとガラス相
の量が増大し、高界面熱抵抗を発現することができない
からである。（ＩＡ族酸化物の合計のモル数）／（Ｃａ
のモル数）の値のさらに好ましい範囲は０．２〜０．４
である。なお、周期律表ＩＡ族に属する元素の酸化物と
しては、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ 2Ｏ、Ｒｂ2Ｏ、Ｃｓ2Ｏ
が例示され、これらの２種以上を用いることができる。In addition, oxidation of elements belonging to Group IA of the periodic table
That two or more types of substances
This is because the softening temperature cannot be reduced effectively.
You. These are contained within the range of the formula (1). 0.13 <(total number of moles of group IA oxide) / (mol of Ca) <0.6 (1) This is (total number of moles of group IA oxide) / (mo
If the value is less than 0.13, caspidyne
The softening temperature is high and the powder
It has no function, while if this value exceeds 0.6, the glass phase
Increases, and high interfacial thermal resistance cannot be developed
Because. (Total number of moles of group IA oxide) / (Ca
Is more preferably in the range of 0.2 to 0.4.
It is. Note that oxides of elements belonging to Group IA of the periodic table
And LiTwoO, NaTwoO, K TwoO, RbTwoO, CsTwoO
And two or more of these can be used.
【００２５】さらに、本発明のモールドパウダーにおい
てＦを５〜１５重量％の範囲としたのは、Ｆ量が５％未
満では軟化温度を低減することができず、一方１５％を
超えると冷却水により連続鋳造機が腐食するためであ
る。Furthermore, in the mold powder of the present invention, F is set in the range of 5 to 15% by weight because the softening temperature cannot be reduced if the F content is less than 5%, while the cooling water cannot be reduced if the F content exceeds 15%. This causes corrosion of the continuous casting machine.
【００２６】本発明において、Ａｌ、Ｍｇ、Ｓｒ、Ｂ
ａ、Ｃｒ、Ｍｎ、Ｆｅの酸化物（Ａｌ2Ｏ3、ＭｇＯ等）
を合計で０．３〜１０重量％含むことが好ましい。これ
らは軟化温度をより低減する効果があるからである。こ
れらが０．３％未満ではこのような効果を得ることがで
きず、１０％を超えるとガラス相の量が増大し、界面熱
抵抗を十分高くすることができない。したがって、これ
らの範囲を０．３〜１０％とした。In the present invention, Al, Mg, Sr, B
a, Cr, Mn, Fe oxides (Al 2 O 3 , MgO, etc.)
Is preferably 0.3 to 10% by weight in total. This is because these have the effect of further reducing the softening temperature. If these are less than 0.3%, such effects cannot be obtained, and if they exceed 10%, the amount of the glass phase increases, and the interface thermal resistance cannot be sufficiently increased. Therefore, these ranges are set to 0.3 to 10%.
【００２７】[0027]
（実施例１）表１に示す組成を有する溶鋼を用い、８種
類のモールドパウダーを使用して実機の連続鋳造機で連
続鋳造試験を行った。鋳造速度は１．８ｍ／ｍｉｎ、モ
ールドサイズは２２０ｍｍ×２０００ｍｍとした。試験
においては、固着層の結晶化率、パウダーの軟化温度、
鋳型内熱流束、および縦割れ発生を評価した。鋳型内熱
流束は鋳型内メニスカス部に埋め込んである熱電対によ
り求めた。鋳片の縦割れ発生頻度は、従来パウダー使用
時における縦割れ発生頻度を１００として指数表示し
た。表２に各パウダーの基材成分と実機試験結果を示
す。この基材に対して外掛けで３重量％となるようにカ
ーボンを添加したものをモールドパウダーとして使用し
た。なお、表２のうち比較例１〜３は従来品であり、発
明例１〜５が本発明の範囲内のものである。(Example 1) A continuous casting test was conducted using a molten steel having a composition shown in Table 1 and an actual continuous casting machine using eight types of mold powders. The casting speed was 1.8 m / min, and the mold size was 220 mm × 2000 mm. In the test, the crystallization rate of the fixed layer, the softening temperature of the powder,
The heat flux in the mold and the occurrence of vertical cracks were evaluated. The heat flux in the mold was determined by a thermocouple embedded in the meniscus in the mold. The frequency of occurrence of vertical cracks in the cast slab was expressed as an index, with the frequency of occurrence of vertical cracks when a conventional powder was used as 100. Table 2 shows the base material components of each powder and the results of actual machine tests. What added carbon so that it might become 3 weight% with respect to this base material in outer case was used as mold powder. In Table 2, Comparative Examples 1 to 3 are conventional products, and Inventive Examples 1 to 5 are within the scope of the present invention.
【００２８】表２に示すように、発明例１〜５は、従来
品である比較例１〜３よりもメニスカス部の熱流束が低
減し、縦割れ指数が低い値を示した。この中でも特に、
Ａｌ、Ｍｇの酸化物が０．３〜１０％の範囲である発明
例１〜４の縦割れ指数が低かった。As shown in Table 2, the inventive examples 1 to 5 showed a lower heat flux at the meniscus portion and a lower value of the vertical cracking index than the comparative examples 1 to 3 which are conventional products. Among them,
Inventive Examples 1 to 4 in which the oxides of Al and Mg were in the range of 0.3 to 10% had a low vertical crack index.
【００２９】[0029]
【表１】 [Table 1]
【００３０】[0030]
【表２】 [Table 2]
【００３１】（実施例２）上記比較例１および発明例１
〜４のパウダーを用い、鋳造速度を２．４ｍ／ｍｉｎと
した以外は実施例１と同様に試験を行った。その結果を
表３に示す。表３に示すように、従来品である比較例１
は縦割れ指数が大幅に増大したが、発明例１〜４は縦割
れ指数が微増するにとどまっており、本発明範囲のパウ
ダーが高速鋳造において良好な結果を示すことが確認さ
れた。Example 2 Comparative Example 1 and Invention Example 1
Tests were conducted in the same manner as in Example 1 except that the casting speed was 2.4 m / min using the powders Nos. 1 to 4 described above. Table 3 shows the results. As shown in Table 3, Comparative Example 1 which is a conventional product
Although the vertical cracking index significantly increased, the vertical cracking index of Invention Examples 1 to 4 increased only slightly, and it was confirmed that the powder in the range of the present invention showed good results in high-speed casting.
【００３２】[0032]
【表３】 [Table 3]
【００３３】[0033]
【発明の効果】以上説明したように、本発明によれば、
鋳型内を従来よりも一層緩冷却化することができる連続
鋳造用モールドパウダーが提供される。したがって、従
来よりも連続鋳造鋳片の縦割れを少なくすることができ
る。As described above, according to the present invention,
Provided is a mold powder for continuous casting that can cool the inside of the mold more slowly than before. Therefore, it is possible to reduce the vertical cracks of the continuously cast slab as compared with the related art.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中田 正之 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 酒井 英典 東京都千代田区丸の内二丁目３番２号 鋼 管鉱業株式会社内 (72)発明者 塩見 剛温 東京都千代田区丸の内二丁目３番２号 鋼 管鉱業株式会社内 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masayuki Nakata 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Inventor Hidenori Sakai 2-3-2, Marunouchi, Chiyoda-ku, Tokyo Steel (72) Inventor, Taketoshi Shiomi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Steel Pipe Mining Co., Ltd.
Claims (3)
２．５の範囲であり、周期律表ＩＡ族に属する元素の酸
化物を２種類以上、以下の（１）式の範囲内で含有し、
かつＦを５〜１５重量％の範囲で含有することを特徴と
する連続鋳造用モールドパウダー。 ０．１３＜（ＩＡ族酸化物の合計のモル数）／（Ｃａのモル数）＜０．６ ……（１） ただし、塩基度のＣａＯ*はパウダー中のＣａのモル数
からＣａＯに換算した値である。1. A basicity (CaO * / SiO 2 ) of 1.6 to 1.
2.5, wherein two or more oxides of elements belonging to Group IA of the periodic table are contained within the range of the following formula (1);
A mold powder for continuous casting, characterized by containing F in a range of 5 to 15% by weight. 0.13 <(total number of moles of group IA oxide) / (number of moles of Ca) <0.6 (1) However, the basicity of CaO * is converted into CaO from the number of moles of Ca in the powder. Value.
物が、Ｌｉ2Ｏ、Ｎａ2Ｏ、Ｋ2Ｏ、Ｒｂ2Ｏ、Ｃｓ2Ｏか
ら選択されたものであることを特徴とする請求項１に記
載の連続鋳造用モールドパウダー。2. An oxide of an element belonging to Group IA of the periodic table, wherein the oxide is selected from Li 2 O, Na 2 O, K 2 O, Rb 2 O, and Cs 2 O. The mold powder for continuous casting according to claim 1.
Ｆｅの酸化物を合計で０．３〜１０重量％含むことを特
徴とする請求項１に記載の連続鋳造用モールドパウダ
ー。3. An Al, Mg, Sr, Ba, Cr, Mn,
2. The mold powder for continuous casting according to claim 1, comprising a total of 0.3 to 10% by weight of an oxide of Fe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03150797A JP3179358B2 (en) | 1997-01-31 | 1997-01-31 | Mold powder for continuous casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03150797A JP3179358B2 (en) | 1997-01-31 | 1997-01-31 | Mold powder for continuous casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10216907A true JPH10216907A (en) | 1998-08-18 |
| JP3179358B2 JP3179358B2 (en) | 2001-06-25 |
Family
ID=12333143
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03150797A Expired - Fee Related JP3179358B2 (en) | 1997-01-31 | 1997-01-31 | Mold powder for continuous casting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3179358B2 (en) |
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| JP2005152931A (en) * | 2003-11-25 | 2005-06-16 | Jfe Steel Kk | Method for continuously casting medium carbon steel slab |
| JP2006247712A (en) * | 2005-03-11 | 2006-09-21 | Jfe Steel Kk | Mold powder for continuous casting of steel |
| JP2009045666A (en) * | 2007-08-22 | 2009-03-05 | Sumitomo Metal Ind Ltd | Mold flux for continuous casting of steel, and continuous casting method using it |
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1997
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005152931A (en) * | 2003-11-25 | 2005-06-16 | Jfe Steel Kk | Method for continuously casting medium carbon steel slab |
| JP4569099B2 (en) * | 2003-11-25 | 2010-10-27 | Ｊｆｅスチール株式会社 | Slab continuous casting method for medium carbon steel |
| JP2006247712A (en) * | 2005-03-11 | 2006-09-21 | Jfe Steel Kk | Mold powder for continuous casting of steel |
| US8146649B2 (en) | 2006-04-25 | 2012-04-03 | Kobe Steel, Ltd. | Method of continuous casting of high-aluminum steel and mold powder |
| JP2009045666A (en) * | 2007-08-22 | 2009-03-05 | Sumitomo Metal Ind Ltd | Mold flux for continuous casting of steel, and continuous casting method using it |
| JP2010227972A (en) * | 2009-03-27 | 2010-10-14 | Shinagawa Refractories Co Ltd | Mold powder for continuously casting steel |
| CN103372637A (en) * | 2012-04-27 | 2013-10-30 | 宝山钢铁股份有限公司 | Crystallizer casting powder |
| CN103372637B (en) * | 2012-04-27 | 2015-07-22 | 宝山钢铁股份有限公司 | Crystallizer casting powder |
| CN108176830A (en) * | 2017-12-28 | 2018-06-19 | 西峡龙成冶金材料有限公司 | A kind of boron-containing steel chamfering copper coin continuous crystallizer protecting slag |
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| Publication number | Publication date |
|---|---|
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