JP2017196643A - Lower nozzle - Google Patents

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JP2017196643A
JP2017196643A JP2016089618A JP2016089618A JP2017196643A JP 2017196643 A JP2017196643 A JP 2017196643A JP 2016089618 A JP2016089618 A JP 2016089618A JP 2016089618 A JP2016089618 A JP 2016089618A JP 2017196643 A JP2017196643 A JP 2017196643A
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lower nozzle
inner hole
nozzle
molten steel
sectional area
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JP6695731B2 (en
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福永 新一
Shinichi Fukunaga
新一 福永
大樹 古川
Hiroki Furukawa
大樹 古川
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Krosaki Harima Corp
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Abstract

PROBLEM TO BE SOLVED: To suppress diffusion of molten steel from a lower nozzle installed downstream of a plate for a sliding nozzle device for controlling a molten steel flow rate of a ladle.SOLUTION: A lower nozzle has a lateral directional sectional area Aof an inner hole bottom end 2 thereof that is smaller than a lateral directional sectional area Aof an inner hole top end 2 thereof. A ratio of (A/A) is preferably 0.5 or more and 0.9 or less.SELECTED DRAWING: Figure 1

Description

本発明は溶鋼排出用の下部ノズルに関する。   The present invention relates to a lower nozzle for discharging molten steel.

取鍋からタンディッシュや鋳型への溶鋼の注湯においては,取鍋底部に溶鋼流量制御機能を備えたスライディングノズル装置を設置し,その下方(下流)にいわゆる下部ノズルを設置して,排出される溶鋼の整流化を行っている。   When pouring molten steel from a ladle to a tundish or mold, a sliding nozzle device with a molten steel flow rate control function is installed at the bottom of the ladle, and a so-called lower nozzle is installed below (downstream) to discharge the molten steel. Rectification of molten steel.

この下部ノズルを取鍋からの溶鋼の最終放出口とする方法の一つとして,例えば連続鋳造操業において,取鍋底部とタンディッシュとの間に,下部ノズルを包含する程度に径の大きい注湯管を設置し,下部ノズルから排出される溶鋼の酸化等を保護する方法がある。しかし,この方法では,下部ノズル下端での溶鋼の拡散が大きくなって,注湯管内壁にスプラッシュによる地金等の付着ないしは閉塞が生じると,鋳造の操業の支障となる。特にスライディングノズル装置のプレートの摺動によりノズル孔径を絞る場合や,下部ノズルの下端部が損傷するとその拡散程度も大きくなる。また,下部ノズルを取鍋からの溶鋼の最終放出口とする方法には,取鍋からインゴット成形用の鋳型に直接注湯する方法もあるが,この方法においても溶鋼の拡散が操業の支障又はインゴット品質の低下の原因になる。   One method of using the lower nozzle as the final discharge port for molten steel from the ladle is, for example, in a continuous casting operation, a pouring process that is large enough to include the lower nozzle between the ladle bottom and the tundish. There is a method to protect the oxidation of molten steel discharged from the lower nozzle by installing a pipe. However, in this method, the diffusion of molten steel at the lower end of the lower nozzle becomes large, and if the metal wall adheres to or clogs due to splash on the inner wall of the pouring pipe, it will hinder the casting operation. In particular, when the diameter of the nozzle hole is reduced by sliding the plate of the sliding nozzle device or when the lower end of the lower nozzle is damaged, the degree of diffusion increases. In addition, there is a method in which the lower nozzle is used as the final discharge port of molten steel from the ladle, and there is a method in which the molten steel is poured directly from the ladle into the mold for ingot molding. Ingot quality is degraded.

前述の下部ノズルを取鍋からの溶鋼の最終放出口とする方法以外に,下部ノズルとタンディッシュ内の鋼浴の間にいわゆるロングノズルと称される長尺の管状ノズルで溶鋼の通過経路を密閉して,溶鋼を保護する方法がある。このロングノズルを使用する方法においても,下部ノズルとロングノズルの接合部付近での溶鋼の拡散がノズル閉塞や接合部付近の破壊等の原因になり,操業の支障又は鋼品質の低下の原因になる。   In addition to the method of using the lower nozzle as the final discharge port for molten steel from the ladle, a long tubular nozzle called a long nozzle is used between the lower nozzle and the steel bath in the tundish to provide a passage path for the molten steel. There is a method of sealing and protecting the molten steel. Even in this method using a long nozzle, diffusion of molten steel near the joint between the lower nozzle and the long nozzle may cause nozzle clogging or breakage near the joint, resulting in operational problems or reduced steel quality. Become.

このような溶鋼の拡散抑制のため,例えば特許文献1には,内部に円筒形状の第1内管部が形成されている上部ノズルに対して,上方部分,下方部分の2つの部分からなり,前記上方部分の内部に円筒形状の第2内管部が形成され,前記下方部分の内部に,前記第2内管部より小口径で先端に向かって先細りの第3内管部が形成されている下部ノズルが着脱可能に装着されており,前記第3内管部の少なくとも前記第2内管部につながる領域が,該第3内管部内方に膨らむ湾曲内面に構成され,前記下部ノズルには,前記第3内管部の少なくとも内面を構成する内挿体が設けられ,該内挿体がジルコニア質材であることを特徴とする鋳造用交換ノズルが提案されている。なお,この特許文献1の上部ノズルには,その下端側にジルコニア質のリング状の内管下端部が装着されて前記第1内管部を形成することも提案されている。   In order to suppress the diffusion of such molten steel, for example, Patent Document 1 includes two parts, an upper part and a lower part, with respect to an upper nozzle in which a cylindrical first inner pipe part is formed. A cylindrical second inner tube portion is formed in the upper portion, and a third inner tube portion that is smaller in diameter than the second inner tube portion and tapered toward the tip is formed in the lower portion. The lower nozzle is detachably mounted, and at least a region of the third inner tube portion connected to the second inner tube portion is formed on a curved inner surface that swells inwardly of the third inner tube portion. Has proposed an exchange nozzle for casting characterized in that an insert is provided which constitutes at least the inner surface of the third inner tube portion, and the insert is a zirconia material. In addition, it has also been proposed that the upper nozzle of Patent Document 1 is provided with a lower end portion of a zirconia ring-shaped inner tube on the lower end side to form the first inner tube portion.

また,特許文献2には,溶鋼を通過させる複数の貫通孔を備えた整流部材が筒状部の内部に設けられた浸漬ノズルを介して,鋳型内に前記溶鋼を注湯する連続鋳造方法が提案されている。   Patent Document 2 discloses a continuous casting method in which a molten metal having a plurality of through-holes through which molten steel is passed is poured into the mold through an immersion nozzle provided inside the cylindrical portion. Proposed.

特開2000−61620号公報JP 2000-61620 A 特開2004−306118号公報JP 2004-306118 A

本発明が解決しようとする課題は,取鍋の溶鋼流量制御用スライディングノズル装置のプレートの下流側に設置される下部ノズルからの溶鋼の拡散を抑制することにある。さらには,下部ノズルの長時間使用時にも拡散抑制効果を持続させることにある。ひいては,前述した注湯管やロングノズル内壁への地金等の付着ないしは閉塞を抑制することにある。   The problem to be solved by the present invention is to suppress the diffusion of molten steel from the lower nozzle installed on the downstream side of the plate of the sliding nozzle device for controlling the molten steel flow rate in the ladle. Furthermore, the diffusion suppression effect is maintained even when the lower nozzle is used for a long time. Eventually, it is to suppress the adhesion or blockage of the metal or the like to the pouring pipe or the inner wall of the long nozzle.

本発明の要旨は,次の1〜5の下部ノズルである。
1.取鍋の溶鋼流量制御用スライディングノズル装置のプレートの下流側に設置される下部ノズルであって,
前記下部ノズルの内孔下端の横方向断面積Aが前記下部ノズルの内孔上端の横方向断面積Aより小さいことを特徴とする,下部ノズル。
2.前記内孔下端の横方向断面積Aの前記内孔上端の横方向断面積Aに対する比(A/A)が0.5以上0.9以下である,前記1に記載の下部ノズル。
3.前記下部ノズルの内孔の一部又は全部には,下方向に向かって内側方向に傾斜する面を備え,前記傾斜する面は,前記内孔を縦方向に分割した一又は複数の領域,又は,前記内孔を円周方向に分割した一又は複数の領域に存在する,前記1又は前記2に記載の下部ノズル。
4.前記下部ノズルの内孔上端から内孔下端の間のいずれかの部分又は全体における前記内孔は,前記プレートの摺動方向に対し直角方向の長さDの,前記プレートの摺動方向の長さDに対する比(D/D)が1.1以上2.0以下である,前記1から前記3のいずれかに記載の下部ノズル。
5.前記下部ノズルの一部又は全部が不定形耐火物により構成されている,前記1から前記4のいずれかに記載の下部ノズル。
The gist of the present invention is the following 1 to 5 lower nozzles.
1. A lower nozzle installed on the downstream side of the plate of the sliding nozzle device for controlling the molten steel flow rate in the ladle,
Wherein the lateral cross-sectional area A L of the inner hole the lower end of the lower nozzle is smaller than the lateral cross-sectional area A U of the bore upper end of the lower nozzle, the lower nozzle.
2. 2. The lower portion according to 1, wherein a ratio (A L / A U ) of the transverse sectional area A L at the lower end of the inner hole to the lateral sectional area A U at the upper end of the inner hole is 0.5 or more and 0.9 or less. nozzle.
3. A part or all of the inner hole of the lower nozzle is provided with a surface inclined inward in the downward direction, and the inclined surface is one or a plurality of regions obtained by dividing the inner hole in the vertical direction, or The lower nozzle according to 1 or 2 above, wherein the lower nozzle is present in one or a plurality of regions obtained by dividing the inner hole in a circumferential direction.
4). The bore in the part or whole either between the inner bore from the lower end the bore upper end of the lower nozzle, the relative sliding direction of the plate perpendicular direction length D 2, in the sliding direction of said plate the ratio of the length D 1 (D 2 / D 1 ) is 1.1 to 2.0, bottom nozzle according to any one of the 1 of the 3.
5. 5. The lower nozzle according to any one of 1 to 4, wherein a part or all of the lower nozzle is made of an irregular refractory.

本発明によれば,取鍋の溶鋼流量制御用スライディングノズル装置のプレートの下流側に設置される下部ノズルからの溶鋼の拡散を抑制することができる。これにより,下部ノズル下端付近の損傷をも抑制することができ,長時間使用時にも拡散抑制効果を持続させることができる。ひいては,注湯管やロングノズル内壁への地金等の付着ないしは閉塞を抑制することができる。   ADVANTAGE OF THE INVENTION According to this invention, the spreading | diffusion of the molten steel from the lower nozzle installed in the downstream of the plate of the sliding nozzle apparatus for molten steel flow control of a ladle can be suppressed. Thereby, damage near the lower end of the lower nozzle can be suppressed, and the diffusion suppressing effect can be maintained even when used for a long time. As a result, the adhesion or blockage of metal or the like to the inner wall of the pouring pipe or the long nozzle can be suppressed.

本発明の下部ノズルの一例のイメージ図で,内孔を縦方向に分割した一部(上方)に傾斜面を備え,前記傾斜面は内孔の円周方向の全部である場合である。It is an image figure of an example of the lower nozzle of the present invention, and it is a case where an inclined surface is provided in a part (upper part) obtained by dividing the inner hole in the vertical direction, and the inclined surface is the entire circumferential direction of the inner hole. 本発明の下部ノズルの一例のイメージ図で,内孔を円周方向に分割した一部で,かつ内孔を縦方向に分割した一部(図1よりさらに上方)に傾斜面を備える場合である。It is an image figure of an example of the lower nozzle of the present invention, and is a case where the inner hole is partly divided in the circumferential direction, and the inner hole is partly divided in the vertical direction (further above FIG. 1) with an inclined surface. . 本発明の下部ノズルの一例のイメージ図で,内孔を円周方向に分割した一部で,かつその部分の内孔縦方向全部に傾斜面を備える場合である。It is an image figure of an example of the lower nozzle of this invention, and is a case where an inner hole is a part divided | segmented into the circumferential direction, and an inclined surface is provided in the whole inner hole vertical direction of the part. 図3の内孔に傾斜面を備えた下部ノズルを下端側から観たイメージ図である。It is the image figure which looked at the lower nozzle provided with the inclined surface in the inner hole of FIG. 3 from the lower end side. 本発明の下部ノズルにおいて,少なくとも内孔面や内孔面下端付近に,他の耐火物又はその外周の耐火物とは異なる材質の耐火物(例えば耐酸化性,耐熱衝撃性及びFeOに対する耐食性,難付着性等が優れている耐火物)を設置した例を示すイメージ図である。In the lower nozzle of the present invention, at least near the inner hole surface and the lower end of the inner hole surface, other refractories or a refractory material different from the outer refractories (for example, oxidation resistance, thermal shock resistance and corrosion resistance against FeO, It is an image figure which shows the example which installed the refractory which is excellent in difficult adhesion etc.). 従来技術の下部ノズルの一例(内孔はほぼ円筒状である場合)を示すイメージ図である。It is an image figure which shows an example (when an inner hole is substantially cylindrical shape) of the lower nozzle of a prior art. 下部ノズルから注湯管内に注湯する場合の溶鋼流動,拡散等のイメージ図である。It is an image figure, such as molten steel flow in the case of pouring in a pouring pipe from a lower nozzle, diffusion. 従来技術の下部ノズル内の溶鋼流動状態を示すイメージ図である。It is an image figure which shows the molten steel flow state in the lower nozzle of a prior art. 本発明の図3の下部ノズル内の溶鋼流動状態を示すイメージ図である。It is an image figure which shows the molten steel flow state in the lower nozzle of FIG. 3 of this invention. 実施例の実験での溶鋼拡散評価を行う部分を示すイメージ図で,(a)は溶鋼流の拡散程度の評価基準W,(b)は溶鋼流の芯ズレの評価基準Xを示す。It is an image figure which shows the part which performs the molten steel spreading | diffusion evaluation in the experiment of an Example, (a) shows the evaluation standard W of the diffusion degree of a molten steel flow, (b) shows the evaluation standard X of the misalignment of a molten steel flow. ,Dを示すイメージ図である。It is a schematic diagram showing a D 1, D 2.

下部ノズルから流出する溶鋼の拡散は,溶鋼流量制御のための,スライディングノズル装置のプレート(以下単に「プレート」という。)の摺動によるノズル径の絞りによって,プレートのノズル孔の全断面積よりも小さな断面積でプレートから溶鋼が吐出することによって生じる。すなわち,ノズル孔径を絞ったプレートから吐出した溶鋼は,例えば図7に実線矢印で示すように複雑かつ偏った速度(速さと方向の要素)となって下部ノズル10の内孔の一部に衝突し,複雑に速度を変えながら落下する。この複雑な速度で下部ノズル下端から開放された溶鋼流は,その下方部分で有する速度に応じた方向に拡散する。   The diffusion of the molten steel flowing out from the lower nozzle is caused by the reduction of the nozzle diameter due to sliding of the sliding nozzle device plate (hereinafter simply referred to as “plate”) for controlling the molten steel flow rate. Is also caused by the discharge of molten steel from the plate with a small cross-sectional area. That is, the molten steel discharged from the plate with the reduced nozzle hole diameter collides with a part of the inner hole of the lower nozzle 10 at a complicated and uneven speed (element of speed and direction) as shown by a solid line arrow in FIG. Then, it falls with complicated speed changes. The molten steel flow released from the lower end of the lower nozzle at this complicated speed diffuses in the direction corresponding to the speed of the lower part.

本発明は,下部ノズル内孔での溶鋼流の挙動,速度をできるだけ均一化することで,下部ノズル下端から放出される溶鋼流の拡散を抑制する。このために本発明の下部ノズルは,下部ノズルの内孔下端の横方向断面積Aが下部ノズルの内孔上端の横方向断面積Aより小さいことを特徴とする。 The present invention suppresses diffusion of the molten steel flow discharged from the lower end of the lower nozzle by making the behavior and speed of the molten steel flow in the lower nozzle inner hole as uniform as possible. The bottom nozzle of the present invention To this end, characterized in that transverse cross-sectional area A L of the bore lower end of the lower nozzle is smaller than the transverse cross-sectional area A U of the bore upper end of the lower nozzle.

このように内孔の横方向断面積を下方向に縮小すると,下方に進むほど溶鋼流速の均一性が高まり,その下端からの溶鋼の拡散が抑制される。   Thus, when the lateral cross-sectional area of the inner hole is reduced downward, the molten steel flow velocity becomes more uniform as it goes downward, and the diffusion of the molten steel from its lower end is suppressed.

前記内孔下端の横方向断面積Aの前記内孔上端の横方向断面積Aに対する比(A/A)は,0.5以上0.9以下であると溶鋼拡散を抑制する効果が高くなり,好ましい。このA/Aの調整は,下方向に向かって内側方向に傾斜する面(傾斜面)を内孔(内孔壁)の一部又は全部に備えることで,内孔の断面積を漸次又は断続的に縮小することにより行うことが好ましい。 When the ratio (A L / A U ) of the transverse sectional area A L at the lower end of the inner hole to the transverse sectional area A U at the upper end of the inner hole is 0.5 or more and 0.9 or less, the diffusion of molten steel is suppressed. The effect is high and preferable. This adjustment of A L / A U is achieved by providing the inner hole (inner hole wall) partially or entirely with a surface (inclined surface) that is inclined inward in the downward direction, so that the sectional area of the inner hole is gradually increased. Or it is preferable to carry out by shrinking | reducing intermittently.

この傾斜面は,縦方向断面において直線,曲線のいずれでもよく、内孔を縦方向に分割した一又は複数の領域,又は,内孔を円周方向に分割した一又は複数の領域に,一又は複数箇所存在する形状とすることができる。また,この傾斜面は,内孔の上端部の中心を下方に貫く中心線に対し,軸対称又は異なる角度を備えた複数面からなる非軸対称であってもよい。言い換えると,内孔の形状は真円の円錐状であってもよく,多様な径の楕円の集合であっても,一部に曲面を含む多角形でもよい。   The inclined surface may be either a straight line or a curved line in the longitudinal cross section, and one inclined surface is divided into one or a plurality of regions obtained by dividing the inner hole in the vertical direction, or one or a plurality of regions obtained by dividing the inner hole in the circumferential direction. Or it can be set as the shape which exists in multiple places. The inclined surface may be axisymmetric with respect to a center line penetrating the center of the upper end portion of the inner hole downward or non-axisymmetrically formed of a plurality of surfaces having different angles. In other words, the shape of the inner hole may be a perfect circular cone, may be a set of ellipses of various diameters, or may be a polygon that includes a curved surface in part.

例えば、図1の下部ノズルは,内孔3を縦方向に分割した一部(上方)に傾斜面4を備え,傾斜面4は内孔の円周方向の全部である場合である。図2の下部ノズルは,内孔を円周方向に分割した一部で,かつ内孔を縦方向に分割した一部(図1よりさらに上方)に傾斜面4を備える場合である。図3の下部ノズルは,内孔を円周方向に分割した一部で,かつその部分の内孔縦方向全部に傾斜面4を備える場合である。   For example, the lower nozzle of FIG. 1 is provided with an inclined surface 4 in a part (upward) of the inner hole 3 divided in the vertical direction, and the inclined surface 4 is the entire circumferential direction of the inner hole. The lower nozzle of FIG. 2 is a case where the inclined surface 4 is provided in a part of the inner hole divided in the circumferential direction and in a part of the inner hole divided in the vertical direction (further above FIG. 1). The lower nozzle in FIG. 3 is a case where the inner hole is partly divided in the circumferential direction, and the inclined surface 4 is provided in the entire longitudinal direction of the inner hole of that part.

また,本発明の下部ノズルにおいて,プレートの摺動方向に対し直角方向の内孔長さDの,プレートの摺動方向の内孔長さDに対する比(D/D)は1.1以上2.0以下であることが好ましい(D,Dについては図11参照)。すなわちこれは,下部ノズルの内孔の横方向断面が,プレートの摺動方向が短辺,摺動方向に直角な方向が長辺の扁平状であることを意味する。この扁平状の内孔形状は,楕円,角が曲面である矩形等,任意の形状でよい。角に屈曲部があると,その部分で溶鋼の拡散が生じやすくなるので,角は曲面からなることが好ましい。 In the lower nozzle of the present invention, the ratio (D 2 / D 1 ) of the inner hole length D 2 in the direction perpendicular to the sliding direction of the plate to the inner hole length D 1 in the sliding direction of the plate is 1. 1 or more and 2.0 or less (refer to FIG. 11 for D 1 and D 2 ). In other words, this means that the transverse cross section of the inner hole of the lower nozzle has a flat shape in which the sliding direction of the plate is short and the direction perpendicular to the sliding direction is long. The flat inner hole shape may be an arbitrary shape such as an ellipse or a rectangle whose corner is a curved surface. If there is a bent portion at the corner, diffusion of the molten steel is likely to occur at that portion, so the corner is preferably a curved surface.

前述の扁平状の内孔形状で(D/D)比を1.1以上2.0以下にするのは,溶鋼の速度の分布がプレートの摺動方向側の位置で大きく変化するからであり,摺動方向側の傾斜程度を摺動方向に直角な方向での傾斜の程度よりも大きくすることで,下部ノズル下端における拡散をより抑制することができる。 The reason why the (D 2 / D 1 ) ratio is 1.1 or more and 2.0 or less in the above-described flat inner hole shape is that the distribution of the speed of the molten steel varies greatly depending on the position on the sliding direction side of the plate. By making the degree of inclination on the sliding direction side larger than the degree of inclination in the direction perpendicular to the sliding direction, diffusion at the lower end of the lower nozzle can be further suppressed.

(D/D)比が1.1未満であると円に近くなって,扁平状の形状にすることによる整流効果が実質的に得られず,(D/D)比が2.0を超えると,プレートの幅,及びスライディングノズル装置の許容限界長さを超えることとなり,現実的ではない。 When the (D 2 / D 1 ) ratio is less than 1.1, the ratio becomes close to a circle, and the rectification effect due to the flat shape cannot be substantially obtained, and the (D 2 / D 1 ) ratio is 2 If it exceeds 0.0, the plate width and the allowable limit length of the sliding nozzle device will be exceeded, which is not practical.

なお、本発明の下部ノズルでは,その内孔上端から内孔下端の間の全体において,前述の扁平状の内孔形状とすることが最も好ましいが,下部ノズルの内孔上端から内孔下端の間の一部において,前述の扁平状の内孔形状とするだけでも一定の整流効果は得られる。   In the lower nozzle of the present invention, it is most preferable that the entire shape between the upper end of the inner hole and the lower end of the inner hole is the above-described flat inner hole shape. A certain rectifying effect can be obtained even if only the above-described flat inner hole shape is formed in a part of the gap.

本発明の下部ノズルの一部又は全部は,不定形耐火物により構成されていてもよい。本発明では,内孔が複雑な形状になる場合があり,その形状によっては生産性の低下等が生じやすくなる。これに対して,下部ノズルの一部又は全部を不定形耐火物により構成するようにすれば,不定形耐火物,特にその流し込み成形等により,より形状の自由度が高まるのに加え,製造もしやすくなる。   Part or all of the lower nozzle of the present invention may be made of an irregular refractory. In the present invention, the inner hole may have a complicated shape, and depending on the shape, a decrease in productivity is likely to occur. On the other hand, if part or all of the lower nozzle is made of an irregular refractory, the shape of the lower refractory, in particular its casting, will increase the degree of freedom of shape, and it will also be manufactured. It becomes easy.

また,例えば図5に示すように,下部ノズルの内孔面の一部又は全部を難付着性の耐火物(図5中の内孔面又は内孔面下端の異材質部分5)により構成すると,溶鋼中のアルミナを主とする非金属介在物の内孔への付着ないしは閉塞を防止することができる。難付着性の耐火物としては,アルミナとの反応性が高い例えばCaOを含有する耐火物,ガラス成分やフッ素成分を含有して耐火物自体が徐々に溶融する組織を含む耐火物等,浸漬ノズル内孔用に一般に使用される耐火物を使用することができる。   Further, for example, as shown in FIG. 5, when a part or all of the inner hole surface of the lower nozzle is made of a hardly adherent refractory material (the inner hole surface in FIG. 5 or the different material portion 5 at the lower end of the inner hole surface). , Non-metallic inclusions mainly composed of alumina in the molten steel can be prevented from adhering to or clogging the inner holes. Examples of difficult-to-adhere refractories include refractories that have high reactivity with alumina, such as refractories that contain CaO, refractories that contain glass and fluorine components, and have a structure in which the refractories themselves gradually melt, etc. Refractories commonly used for inner holes can be used.

[実施例A]
実施例Aは,下部ノズルの内孔下端の横方向断面積Aの内孔上端の横方向断面積Aに対する比(A/A)が溶鋼流の拡散及び芯ズレの程度に及ぼす影響を確認した水モデル実験結果である。この実験では,下部ノズルの全長は290mm,前記(H/L)比を3.6とし,D/D比は1.0(円形)とした。下部ノズルの内孔は図3の構造とした。
[Example A]
Example A exerts ratio transverse cross-sectional area A U of the bore upper end of the lateral cross-sectional area A L of the bore lower end of the lower nozzle (A L / A U) is the degree of diffusion and misalignment of the molten steel flow It is the water model experiment result which confirmed the influence. In this experiment, the total length of the lower nozzle was 290 mm, the (H / L 1 ) ratio was 3.6, and the D 2 / D 1 ratio was 1.0 (circular). The inner hole of the lower nozzle has the structure shown in FIG.

溶鋼流の拡散の評価は,図10(a)に示すWで評価し,従来技術(内孔が円筒状,図6参照)の典型例である比較例1のWを基準とした。芯ズレは,溶鋼流の横方法の中心がノズルの縦方向中心からずれる場合のそのズレの程度であって,図10(b)に示すZで評価した。本発明の拡散抑制の効果は,前記Wと前記Xとの合計で評価し,従来技術(比較例1)に対する改善有無及び程度で評価した。   Evaluation of the diffusion of the molten steel flow was performed using W shown in FIG. 10 (a), and was based on W in Comparative Example 1, which is a typical example of the prior art (inner hole is cylindrical, see FIG. 6). The misalignment is the degree of misalignment when the center of the horizontal method of the molten steel flow deviates from the longitudinal center of the nozzle, and was evaluated by Z shown in FIG. The effect of suppressing the diffusion of the present invention was evaluated by the total of the W and the X, and evaluated by the presence / absence and degree of improvement over the prior art (Comparative Example 1).

表1にその構成と結果を示す。

Figure 2017196643
Table 1 shows the configuration and results.
Figure 2017196643

<Aの実施例1〜実施例5では、拡散抑制の効果が得られることがわかる。また拡散抑制の効果は,(A/A)比が0.5〜0.9の範囲がより顕著で好ましいことがわかる。 In Examples 1 to 5 where A L <A U , it can be seen that the effect of suppressing diffusion is obtained. Effect of addition diffusion suppression, (A L / A U) ratio is found to be preferable and more pronounced in the range of 0.5 to 0.9.

なお,図8には,従来技術(比較例1)の下部ノズル内の溶鋼流動状態(イメージ)を示し、図9には,本発明の図3の下部ノズル内の溶鋼流動状態(イメージ)を示している。   8 shows the molten steel flow state (image) in the lower nozzle of the prior art (Comparative Example 1), and FIG. 9 shows the molten steel flow state (image) in the lower nozzle of FIG. 3 of the present invention. Show.

[実施例B]
実施例Bは,下部ノズル下端面のD/D比を変化させて,拡散抑制の効果を水モデル実験により調査した例である。D/D比以外は実施例Aと同じ条件である。
[Example B]
Example B is an example in which the D 2 / D 1 ratio of the lower end surface of the lower nozzle is changed and the effect of suppressing diffusion is investigated by a water model experiment. The conditions are the same as in Example A except for the D 2 / D 1 ratio.

表2にその構成と結果を示す。

Figure 2017196643
Table 2 shows the configuration and results.
Figure 2017196643

/D比がいずれの場合も前記比較例1に対し顕著な拡散抑制の効果が得られることがわかる。しかし,D/D比が2.3の場合は1.0の場合(実施例3)に比較して拡散及び芯ズレが大きくなる傾向があり,D/D比は1.1〜2.0の範囲が好ましいことがわかる。 It can be seen that any diffusion ratio can be obtained as compared with Comparative Example 1 in any case of the D 2 / D 1 ratio. However, when the D 2 / D 1 ratio is 2.3, the diffusion and misalignment tend to increase compared to the case of 1.0 (Example 3), and the D 2 / D 1 ratio is 1.1. It can be seen that a range of ˜2.0 is preferable.

1 下部ノズルの内孔上端(この断面積がAである。)
2 下部ノズルの内孔下端(この断面積がAである。)
3 内孔
4 内孔の傾斜面
5 内孔面又は内孔面下端の異材質部分
6 下部ノズルの内孔下端から拡散した溶鋼流
10 下部ノズル
20 注湯管
30 スライディングノズル装置のプレート
1 Upper end of inner hole of lower nozzle (this cross-sectional area is Au )
It bores lower end of second lower nozzle (this cross-sectional area is A L.)
3 Inner hole 4 Inclined surface of inner hole 5 Dissimilar material part of inner hole surface or lower end of inner hole surface 6 Molten steel flow diffused from lower end of inner hole of lower nozzle 10 Lower nozzle 20 Pouring pipe 30 Plate of sliding nozzle device

Claims (5)

取鍋の溶鋼流量制御用スライディングノズル装置のプレートの下流側に設置される下部ノズルであって,
前記下部ノズルの内孔下端の横方向断面積Aが前記下部ノズルの内孔上端の横方向断面積Aより小さいことを特徴とする,下部ノズル。
A lower nozzle installed on the downstream side of the plate of the sliding nozzle device for controlling the molten steel flow rate in the ladle,
Wherein the lateral cross-sectional area A L of the inner hole the lower end of the lower nozzle is smaller than the lateral cross-sectional area A U of the bore upper end of the lower nozzle, the lower nozzle.
前記内孔下端の横方向断面積Aの前記内孔上端の横方向断面積Aに対する比(A/A)が0.5以上0.9以下である,請求項1に記載の下部ノズル。 2. The ratio (A L / A U ) of the transverse sectional area A L at the lower end of the inner hole to the lateral sectional area A U at the upper end of the inner hole is 0.5 or more and 0.9 or less. Lower nozzle. 前記下部ノズルの内孔の一部又は全部には,下方向に向かって内側方向に傾斜する面を備え,前記傾斜する面は,前記内孔を縦方向に分割した一又は複数の領域,又は,前記内孔を円周方向に分割した一又は複数の領域に存在する,請求項1又は請求項2に記載の下部ノズル。   A part or all of the inner hole of the lower nozzle is provided with a surface inclined inward in the downward direction, and the inclined surface is one or a plurality of regions obtained by dividing the inner hole in the vertical direction, or The lower nozzle according to claim 1, wherein the lower nozzle is present in one or a plurality of regions obtained by dividing the inner hole in a circumferential direction. 前記下部ノズルの内孔上端から内孔下端の間のいずれかの部分又は全体において,前記プレートの摺動方向に対し直角方向の内孔長さDの,前記プレートの摺動方向の内孔長さDに対する比(D/D)が1.1以上2.0以下である,請求項1から請求項3のいずれかに記載の下部ノズル。 In any part or whole between the inner bore from the lower end the bore upper end of the lower nozzle, the inner hole of the length D 2 of the direction perpendicular to the sliding direction of the plate, the plate inner hole of the sliding direction of the the ratio of the length D 1 (D 2 / D 1 ) is 1.1 to 2.0, the lower nozzle according to any one of claims 1 to 3. 前記下部ノズルの一部又は全部が不定形耐火物により構成されている,請求項1から請求項4のいずれかに記載の下部ノズル。   The lower nozzle according to any one of claims 1 to 4, wherein a part or all of the lower nozzle is made of an irregular refractory.
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