JPH0456704B2 - - Google Patents
Info
- Publication number
- JPH0456704B2 JPH0456704B2 JP62095280A JP9528087A JPH0456704B2 JP H0456704 B2 JPH0456704 B2 JP H0456704B2 JP 62095280 A JP62095280 A JP 62095280A JP 9528087 A JP9528087 A JP 9528087A JP H0456704 B2 JPH0456704 B2 JP H0456704B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- flow
- molten steel
- mold
- static magnetic
- 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 - Lifetime
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 35
- 239000010959 steel Substances 0.000 claims description 35
- 230000003068 static effect Effects 0.000 claims description 25
- 238000009749 continuous casting Methods 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 11
- 238000007654 immersion Methods 0.000 claims description 10
- 238000013019 agitation Methods 0.000 claims description 3
- 230000003993 interaction Effects 0.000 claims description 3
- 238000005266 casting Methods 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 230000007547 defect Effects 0.000 description 3
- 230000005499 meniscus Effects 0.000 description 3
- 230000004907 flux Effects 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
Landscapes
- Continuous Casting (AREA)
Description
（産業上の利用分野）
この発明は、連続鋳造におけるモールドパウダ
ーの巻き込み防止方法に関し、とくに連鋳鋳型内
の溶鋼湯面の攪拌を効果的に軽減させることによ
つて、溶鋼中へのモールドパウダー性非金属介在
物の巻き込み防止し、もつて清浄鋼を得ようとす
るものである。
（従来の技術）
鋼の連続鋳造においては、鋳型内において浸漬
ノズルからの吐出溶鋼流がモールド壁に衝突し、
その一部がメニスカス部への上昇流となつて湯面
の乱れを生じることが知られている。かような上
昇流が過大な場合には、モールドパウダーが溶鋼
中に巻き込まれて鋼材の表面欠陥となる。
このため浸漬ノズルからの溶鋼の吐出角度を鋳
造量に応じて適切な値に選択する等の手段が一般
的に講じられている。しかしながらかような対策
では浸漬ノズルの溶損が著しくまたアルミナの付
着などにより鋳造中にその形状が変化することか
ら適切な方法とは言い難い。
その他特開昭57−17356号公報において、連鋳
モールド内の溶鋼の流動を静磁界で減速して分散
させる技術が提案されている。
（発明が解決しようとする問題点）
しかしながら上記の技術は、溶鋼流の未凝固鋳
造域内部への侵入深さの減少を主目的としたもの
であつて、湯面への溶鋼流を減少することを想定
したものではないため、モールドパウダーの巻き
込みによる製品欠陥を完全に防止することはでき
ないところに問題を残していた。
この発明は、上記の問題を有利に解決するもの
で、連鋳モールド内で、溶鋼の吐出流がモールド
壁に衝突した後の上昇流が湯面に到達するまでの
中間位置に該溶鋼の流動方向と交差する向きに静
磁場を作用させてその流動を減速し、もつて溶鋼
メニスカスへの流動速度を減じることによつて溶
鋼中へのモールドパウダーの巻き込みを減少させ
る、連続鋳造におけるモールドパウダーの巻き込
み防止方法を提案することを目的とする。
（問題点を解決するための手段）
まずこの発明の解明経緯について説明する。
発明者らは、静磁場による溶鋼の減速に関して
種々の実験と検討を行つたところ、以下の知見を
得た。
(1) 静磁場内の溶鋼の流れは磁場の勾配部で生じ
る渦電流と磁場の相互作用によつて減速され
る。
(2) その結果生じる滑らかな流れは磁束分布の等
磁束密度線に沿つて流れる。
以上の知見から、流れを効果的に抑えるには、
静磁場中に流れが入るように静磁場を印加するこ
とが重要であることが判明した。
この発明は、上記の知見に立脚するものであ
る。すなわちこの発明は、連続鋳造用鋳型の対向
側壁間に静磁場を形成させ、この磁場と溶鋼流動
との作用で生じる誘導電流に基く電磁力によつて
溶鋼の流れを制御する連続鋳造方法において、
浸漬ノズルからの吐出溶鋼流が衝突する鋳型短
辺位置と湯面との間でかつ、湯面から50mm以上下
方において静磁場を印加することにより、鋳型短
辺に沿う溶鋼上昇流を減速し、もつて湯面の攪拌
を軽減させることからなる、連続鋳造におけるモ
ールドパウダーの巻き込み防止方法である。
以下この発明を具体的に説明する。
第１図にこの発明の実施に用いて好適な連続鋳
造用鋳型を断面で示す。
図中番号１は浸漬ノズル、２は鋳型短辺、３は
浸漬ノズル１からの吐出溶鋼流、４は該吐出溶鋼
流３の衝突位置であり、５，６がそれぞれ鋳型短
辺２に沿う溶鋼の上昇流および下降流である。
また７は湯面（メニスカス）、８はモールドパ
ウダー、そして９が静磁場である。
さて浸漬ノズル１から吐出された溶鋼流３は、
鋳型短辺２に衝突したのち、その一部は上昇流と
なつて湯面に直角な向きに流れていくわけである
が、この発明では、溶鋼流３の衝突位置４と湯面
７との間で、かつ上昇流を交わる向きに静磁場９
が印加されているので、この静磁場９によつて上
昇流５は効果的に減速されるのである。
（作用）
ここに静磁場の印加位置は、湯面より50mm以上
下方とする必要がある。というのは静磁場の印加
開始位置があまりに湯面に近ずくと磁界の作用時
間が短くなり、制動力の生ずる効果が減少すると
いう不利が生じるからである。
第２図に、静磁場の印加位置と上昇流の減速比
率との関係について調べた結果を示す。ここに減
速比率とはEMBR印加時の短辺上昇流速／
EMBR無印加時の短辺上昇流速のことである。
同図より明らかなように、静磁場の印加位置を
湯面から50mm以上下方とすることによつてとりわ
け良好な減速効果が得られている。
なお、静磁場の印加位置は、湯面から50mm以上
下方とはいえ、浸漬ノズルからの溶鋼吐出流の流
動を妨害しない位置とする必要があるのはいうま
でもない。
次に第３図に、印加する静磁場の強さと上昇流
減速効果との関係について調べた結果を、印加磁
場の強さと上昇流減速比率との関係で示す。
同図より明らかなように、印加磁場の強さが強
いほど上昇流の減速効果は高くなるが、実用的な
注入速度：１〜4ton／minの下でも、十分満足の
いく制動作用を確保するためには、磁場の強さは
1500エルステツド以上とすることが好ましい。
（実施例）
厚み：220mm、幅：1350〜1500mmの彎曲型スラ
ブ連鋳機において、次の条件でスラブ製造を行な
つた。
(1) 鋳造鋼種
(Industrial Application Field) The present invention relates to a method for preventing mold powder from being entrained in continuous casting, and in particular, by effectively reducing the agitation of the molten steel surface in a continuous casting mold, mold powder is prevented from being mixed into molten steel. The aim is to prevent the entrainment of non-metallic inclusions and to obtain clean steel. (Prior art) In continuous steel casting, a flow of molten steel discharged from a submerged nozzle collides with the mold wall in the mold.
It is known that a part of the water flows upward toward the meniscus and causes disturbances in the hot water level. If such an upward flow is excessive, mold powder will be drawn into the molten steel and cause surface defects on the steel material. For this reason, measures are generally taken such as selecting an appropriate value for the discharge angle of molten steel from the immersion nozzle depending on the amount of casting. However, such a measure is not an appropriate method because the immersion nozzle suffers from significant erosion and its shape changes during casting due to adhesion of alumina. In addition, JP-A-57-17356 proposes a technique for slowing down and dispersing the flow of molten steel in a continuous casting mold using a static magnetic field. (Problems to be Solved by the Invention) However, the above-mentioned techniques are mainly aimed at reducing the penetration depth of the molten steel flow into the unsolidified casting region, and do not reduce the molten steel flow to the molten metal surface. However, the problem remains that it is not possible to completely prevent product defects due to mold powder being involved. The present invention advantageously solves the above-mentioned problem, and in a continuous casting mold, the molten steel flows at an intermediate position after the molten steel discharge flow collides with the mold wall and before the upward flow reaches the molten metal surface. A method for mold powder in continuous casting that applies a static magnetic field in a direction that intersects the direction of the mold powder to slow down its flow, thereby reducing the flow rate to the molten steel meniscus and thereby reducing the entrainment of the mold powder into the molten steel. The purpose is to propose a method to prevent entanglement. (Means for Solving the Problems) First, the background to the elucidation of this invention will be explained. The inventors conducted various experiments and studies regarding the deceleration of molten steel by a static magnetic field, and obtained the following knowledge. (1) The flow of molten steel in a static magnetic field is slowed down by the interaction between the eddy currents generated at the gradient of the magnetic field and the magnetic field. (2) The resulting smooth flow follows the equal flux density lines of the magnetic flux distribution. From the above knowledge, in order to effectively suppress the flow,
It was found that it is important to apply a static magnetic field so that the flow enters the static magnetic field. This invention is based on the above knowledge. That is, the present invention provides a continuous casting method in which a static magnetic field is formed between opposing side walls of a continuous casting mold, and the flow of molten steel is controlled by electromagnetic force based on an induced current generated by the interaction of this magnetic field and the molten steel flow. By applying a static magnetic field between the short side of the mold where the molten steel flow discharged from the immersion nozzle collides with the molten metal surface and at least 50 mm below the molten metal surface, the upward flow of molten steel along the short side of the mold is decelerated. This is a method for preventing mold powder from being entrained in continuous casting by reducing the agitation of the molten metal surface. This invention will be specifically explained below. FIG. 1 shows a cross-sectional view of a continuous casting mold suitable for use in carrying out the present invention. In the figure, number 1 is the immersion nozzle, 2 is the mold short side, 3 is the molten steel flow discharged from the immersion nozzle 1, 4 is the collision position of the discharged molten steel flow 3, and 5 and 6 are the molten steel along the mold short side 2. The upflow and downflow of Also, 7 is the hot water surface (meniscus), 8 is the mold powder, and 9 is the static magnetic field. Now, the molten steel flow 3 discharged from the immersion nozzle 1 is
After colliding with the short side 2 of the mold, a part of it becomes an upward flow and flows in a direction perpendicular to the molten metal surface, but in this invention, the collision position 4 of the molten steel flow 3 and the molten metal surface 7 are A static magnetic field 9 between the
is applied, the upward flow 5 is effectively decelerated by the static magnetic field 9. (Function) The position where the static magnetic field is applied must be at least 50 mm below the hot water level. This is because if the application start point of the static magnetic field is too close to the hot water surface, the operating time of the magnetic field will be shortened, resulting in a disadvantage that the effect of the braking force will be reduced. FIG. 2 shows the results of an investigation into the relationship between the application position of the static magnetic field and the deceleration ratio of the upward flow. Here, the deceleration ratio is the short side upward flow velocity when EMBR is applied /
This is the upward flow velocity on the short side when no EMBR is applied. As is clear from the figure, a particularly good deceleration effect is obtained by applying the static magnetic field at a position 50 mm or more below the hot water level. It goes without saying that the static magnetic field is applied at a position that does not interfere with the flow of the molten steel discharged from the immersion nozzle, even though it is 50 mm or more below the molten metal surface. Next, FIG. 3 shows the results of an investigation into the relationship between the strength of the applied static magnetic field and the upflow deceleration effect, in terms of the relationship between the strength of the applied magnetic field and the upflow deceleration ratio. As is clear from the figure, the stronger the applied magnetic field, the higher the effect of slowing down the upward flow, but even at a practical injection rate of 1 to 4 ton/min, a sufficiently satisfactory braking effect can be ensured. For this, the strength of the magnetic field is
It is preferable to set it to 1500 oersted or more. (Example) Slabs were manufactured under the following conditions in a curved continuous slab casting machine having a thickness of 220 mm and a width of 1350 to 1500 mm. (1) Casting steel type
【表】
(2) 鋳造スループツト：3.2〜3.5ton／min
浸漬ノズルからの溶鋼吐出角度：下向き15°
湯面と静磁場との距離ｈ：75mm
静磁場の強さ：1000〜3000エルステツド
鋳造は合計2000ton行ない、製品欠陥（スリバ
ー評点、ブリスター評点）について調査した。
得られた結果、次表１に示す。[Table] (2) Casting throughput: 3.2 to 3.5 ton/min Molten steel discharge angle from immersion nozzle: 15° downward Distance h between molten metal surface and static magnetic field: 75 mm Static magnetic field strength: 1000 to 3000 oersted Casting is total 2000 tons were tested and product defects (sliver rating, blister rating) were investigated. The results obtained are shown in Table 1 below.
【表】
（発明の効果）
かくしてこの発明によれば、連続鋳造において
従来懸念されたモールドパウダーの巻き込みを効
果的に防止することができ、ひいては清浄鋼が得
られ製品品質の向上に役立つ。[Table] (Effects of the Invention) Thus, according to the present invention, the entrainment of mold powder, which was a conventional concern in continuous casting, can be effectively prevented, and as a result, clean steel can be obtained, which is useful for improving product quality.
第１図は、この発明の実施に用いて好適な連続
鋳造用鋳型の断面図、第２図は、湯面と静磁場印
加位置との間の距離と、静磁場印加による短辺上
昇流減速比率との関係を示したグラフ、第３図
は、印加磁場の強さと、静磁場印加による短辺上
昇流減速比率との関係を示したグラフである。
１……浸漬ノズル、２……鋳型短辺、３……溶
鋼吐出流、４……溶鋼吐出流の衝突位置、５……
上昇流、６……下降流、７……湯面、８……モー
ルドパウダー、９……静磁場。
FIG. 1 is a sectional view of a continuous casting mold suitable for carrying out the present invention, and FIG. 2 shows the distance between the molten metal surface and the static magnetic field application position and the deceleration of upward flow on the short side due to the application of the static magnetic field. FIG. 3 is a graph showing the relationship between the strength of the applied magnetic field and the short side upward flow deceleration ratio due to the application of the static magnetic field. 1... Immersion nozzle, 2... Short side of the mold, 3... Molten steel discharge flow, 4... Collision position of the molten steel discharge flow, 5...
Upward flow, 6... Downward flow, 7... Hot water level, 8... Mold powder, 9... Static magnetic field.
Claims (1)
させ、この磁場と溶鋼流動との作用で生じる誘導
電流に基く電磁力によつて溶鋼の流れを制御する
連続鋳造方法において、 浸漬ノズルからの吐出溶鋼流が衝突する鋳型短
辺位置と湯面との間でかつ、湯面から50mm以上下
方において静磁場を印加することにより、鋳型短
辺に沿う溶鋼上昇流を減速し、もつて湯面の攪拌
を軽減させることからなる、連続鋳造におけるモ
ールドパウダーの巻き込み防止方法。[Claims] 1. A continuous casting method in which a static magnetic field is formed between opposing side walls of a continuous casting mold, and the flow of molten steel is controlled by electromagnetic force based on an induced current generated by the interaction of this magnetic field and the molten steel flow. In this method, the upward flow of molten steel along the short side of the mold is decelerated by applying a static magnetic field between the short side of the mold where the flow of molten steel discharged from the immersion nozzle collides with the molten metal surface, and at least 50 mm below the molten metal surface. A method for preventing entrainment of mold powder in continuous casting, which consists of reducing the agitation of the molten metal surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9528087A JPS63260652A (en) | 1987-04-20 | 1987-04-20 | Method for preventing involvement of mold powder in continuous casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9528087A JPS63260652A (en) | 1987-04-20 | 1987-04-20 | Method for preventing involvement of mold powder in continuous casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63260652A JPS63260652A (en) | 1988-10-27 |
| JPH0456704B2 true JPH0456704B2 (en) | 1992-09-09 |
Family
ID=14133363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9528087A Granted JPS63260652A (en) | 1987-04-20 | 1987-04-20 | Method for preventing involvement of mold powder in continuous casting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63260652A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0673722B2 (en) * | 1988-09-09 | 1994-09-21 | 新日本製鐵株式会社 | Continuous casting method |
| JP2898355B2 (en) * | 1989-06-09 | 1999-05-31 | 新日本製鐵株式会社 | Flow control method for molten steel in mold |
| DE69230666T2 (en) * | 1991-09-25 | 2000-06-08 | Kawasaki Steel Co | METHOD FOR CONTINUOUSLY STEEL USING MAGNETIC FIELDS |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5717356A (en) * | 1980-05-19 | 1982-01-29 | Asea Ab | Method and apparatus for agitating casting strand non-coagulated region |
| JPS5855157A (en) * | 1981-09-28 | 1983-04-01 | Sumitomo Metal Ind Ltd | Method and device for controlling charged flow in continuous casting |
| JPS61129261A (en) * | 1984-11-28 | 1986-06-17 | Nippon Steel Corp | Production of continuously cast steel ingot having less surface defect |
-
1987
- 1987-04-20 JP JP9528087A patent/JPS63260652A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5717356A (en) * | 1980-05-19 | 1982-01-29 | Asea Ab | Method and apparatus for agitating casting strand non-coagulated region |
| JPS5855157A (en) * | 1981-09-28 | 1983-04-01 | Sumitomo Metal Ind Ltd | Method and device for controlling charged flow in continuous casting |
| JPS61129261A (en) * | 1984-11-28 | 1986-06-17 | Nippon Steel Corp | Production of continuously cast steel ingot having less surface defect |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63260652A (en) | 1988-10-27 |
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