JP2017177195A - Soaking nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soaking nozzle capable of restraining sticking of an inclusion in molten steel to the discharge hole route periphery.SOLUTION: A cross section of cutting a discharge hole route 4 by a surface S1 parallel to the length direction of a nozzle body 2, has a shape of a pentagon where three apexes A, B and C are positioned closer to the tip part 2a side than the other apexes E and F. Assuming an angle formed by a line segment connecting the apex A and the apex B and a line segment connecting the apex A and the apex C as α, 90°≤α≤180°is satisfied. An intersection between an end surface 3a and a virtual line L extending in the length direction of a flow passage 3 by passing through the center O of a cross section of a circular shape obtained by cutting the flow passage by a surface S2 vertical to the length direction of the flow passage 3, is set as a point D. The pint D includes the respective apexes B in the cross section by the respective surfaces S1 of the respective discharge hole routes 4, and is positioned on a virtual plane P1 vertical to the virtual line L or on the opposite side of a tip part 2a to the virtual plane P1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an immersion nozzle, and more particularly to an immersion nozzle that is used in a continuous casting apparatus that continuously casts steel pieces such as slabs, blooms, and billets from molten steel.

  In continuous casting machines, immersion nozzles are widely used to inject molten steel from the tundish into the mold. The immersion nozzle has an important role in preventing molten steel from coming into direct contact with the atmosphere and being reoxidized, and is an important refractory material that greatly contributes to improving the quality of the slab.

Factors governing the durability of the immersion nozzle are the local erosion caused by mold powder slag, which is sprayed on the surface of the molten steel in the mold and used for the purpose of preventing reoxidation of molten steel and absorbing and removing inclusions in the steel. It is roughly divided into nozzle clogging due to adhesion of metal and non-metal to the inner pipe. Among these, with respect to nozzle clogging, if the degree of clogging is large, casting itself may not be continued. If production according to the operation plan becomes difficult, it will greatly affect productivity and profitability. Further, even when casting does not become impossible, the inner pipe flow path of the immersion nozzle is reduced by the occurrence of adhesion, and the flow rate and flow pattern of the discharge flow supplied into the mold may change. Since the flow pattern of the discharge flow supplied into the mold is optimized according to the casting conditions, if the flow pattern changes due to clogging, the incidence rate of inclusion defects and bubble defects increases, resulting in casting. This leads to a drop in quality. In particular, when casting ultra-low carbon steel, Al is added to reduce oxygen (O) in the steel, so alumina (Al ₂ O ₃ ) inclusions are generated in the steel, resulting in blockage. Trouble occurs easily.

  FIG. 7 shows the state of attachment of inclusions around the discharge hole 105 in the conventional immersion nozzle 100. FIG. 7A shows a front view of the immersion nozzle 100 viewed in a direction perpendicular to the discharge hole 105, and FIG. 7B is a plane including the longitudinal axis 110 of the immersion nozzle 100. FIG. 7C shows an end view of the cut surface obtained by cutting the immersion nozzle 100, and FIG. 7C shows an end view of the cut surface obtained by cutting the immersion nozzle 100 in a plane perpendicular to the plane of FIG. 7B. Yes. As shown in FIG. 7B, the immersion nozzle 100 is formed with a cylindrical flow passage 103 extending in the length direction and concentrically with the nozzle body 102. The flow passage 103 is often formed in an elliptic cylinder shape. The flow passage 103 is closed by an end surface 103 a on the tip end portion 102 a side of the nozzle body 102. The nozzle main body 102 is formed with two discharge hole paths 104 having one end communicating with the flow passage 103 and the other end opening on the outer peripheral surface 102 c of the nozzle main body 102. Each discharge hole path 104 is inclined toward the distal end portion 102a from the one end toward the other end. As shown in FIG. 7A, the discharge hole 105 in which the discharge hole path 104 opens on the outer peripheral surface 102c has a rectangular shape.

  As shown in FIG. 7C, the deposit 106 is greatly developed from the inner peripheral surface 103 b to the end surface 103 a of the flow passage 103. As shown in FIG. 7A, the deposit 106 attached to the inner peripheral surface 103b develops so as to block a part of the opening surface opened to the inner peripheral surface 103b of the discharge hole path 104. Further, as shown in FIG. 7B, the deposit 106 adhering to the end surface 103a develops into the discharge hole path 104, adheres to a part of the discharge hole path 104, and a part of the deposit 106. Protrudes outward from the discharge hole 105.

  As a measure to prevent the inclusions such as alumina from adhering to the flow passage 103, an appropriate amount of inert gas such as argon is blown from the immersion nozzle and the refractory upstream thereof to adsorb the inclusions on the surface of the gas bubbles. The method of floating and removing is widely adopted. Further, studies are also being made on a method of arranging a hardly adherent material on the inner peripheral surface 103 b of the flow passage 103.

  Adhesion of the flow passage 103 to the inner peripheral surface 103b is greatly improved by the above-mentioned measures, and if an appropriate gas blowing amount and a difficult-to-adhere material are applied, the casting is forced to be stopped due to the blockage of the flow passage 103. Serious problems have almost never occurred. However, in the vicinity of the discharge hole 105 where the molten steel flow is supplied from the immersion nozzle 100 to the mold, there are still some cases where there is much adhesion. The same position is a part that finally determines the discharge flow velocity and the discharge direction of the molten steel flow, and it is very important to prevent adhesion at the same position. In order to prevent adhesion at the same position, for example, Patent Document 1 discloses a form in which a hardly adherent material is provided in the discharge hole path 104 in addition to the inner peripheral surface 103 b of the flow passage 103.

JP 2007-130653 A

  However, it is difficult to provide a difficult-to-adhere material in the discharge hole path 104 due to manufacturing difficulties, and the problem of adhesion around the discharge hole 105 has not been completely solved.

  This invention was made in order to solve such a problem, and it aims at providing the immersion nozzle which can suppress the adhesion of the inclusion in molten steel to a discharge path hole periphery.

An immersion nozzle according to the present invention includes a nozzle body, a cylindrical or elliptical column-shaped flow passage provided in the nozzle body so as to extend in the length direction, one end communicating with the flow passage, and the other end And at least two discharge hole paths having discharge holes opened on the outer peripheral surface of the nozzle body, and the cross section of the discharge hole path cut by a surface parallel to the length direction of the nozzle body has three vertices at the other two points. It has a pentagonal shape that is located closer to the tip of the nozzle body than the vertex, and of the three vertices, the middle vertex in the direction perpendicular to the length direction of the nozzle body is designated as vertex A, and the remaining two vertices Assuming that vertex B and vertex C are located, vertex A is positioned closer to the tip of the nozzle body than vertex B and vertex C, and a line segment connecting vertex A and vertex B and a line segment connecting vertex A and vertex C are If the angle formed is α, 90 ° ≦ α < The flow passage is 80 °, and the flow passage has an end face that is closed on the tip end side of the nozzle body, and passes through the center of a circular cross-section obtained by cutting the flow passage along a plane perpendicular to the length direction of the flow passage. Assuming that an intersection of an imaginary line extending in the length direction of the path and the end face is a point D, the point D includes a vertex A in the cross section of each discharge hole path and is on a virtual plane perpendicular to the length direction of the nozzle body. Or on the opposite side of the tip of the nozzle body with respect to the virtual plane.
If the angle formed by the line segment connecting the vertex A and the point D and the virtual line is β, 30 ° ≦ β ≦ 90 ° may be satisfied.

  According to this invention, since the concentration of turbulent energy in the vicinity of the inner peripheral surface of the flow passage is suppressed in the molten steel flow that flows through the flow passage of the submerged nozzle, the flow passage to the inner peripheral surface of the flow passage around the discharge hole route is suppressed. Adhesion of inclusions in the molten steel can be suppressed.

It is a figure which shows the result of the internal energy (KE) in the molten steel flow computed by the numerical fluid dynamics (CFD) calculation in the conventional immersion nozzle. It is a perspective view of the immersion nozzle which concerns on embodiment of this invention. It is the partial end surface of the cross section cut | disconnected in three different positions of the immersion nozzle which concerns on this embodiment. It is the partial end elevation of the section cut at two different positions of the modification of the immersion nozzle concerning this embodiment. In the immersion nozzle of Example 3, it is a figure which shows the result of the internal energy (KE) in the molten steel flow computed by numerical fluid dynamics (CFD) calculation. It is a figure which shows the comparison of the adhesion amount of the alumina inclusion of the comparative example 1 and Example 3 in actual machine use. It is an illustration figure which shows the adhesion condition of the inclusion around the discharge hole in the conventional immersion nozzle.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, as an example of the case where a lot of adhesion is recognized around the discharge hole of the conventional immersion nozzle, what phenomenon occurs in the vicinity of the portion where the adhesion occurs with respect to the immersion nozzle 100 shown in FIG. Computational fluid dynamics (CFD) calculation was performed to confirm whether or not Commercially available program PHOENICS was used for CFD calculation.

  FIG. 1 shows a contour of the CFD calculation result on the same surface as that shown in FIG. 7C for the conventional immersion nozzle 100. According to this, it became clear that the turbulent energy is locally increased in the vicinity of the inner peripheral surface 103 b of the flow passage 103. In addition, at that part, the flow flowing down from the top collides with the end face 103a, partly inverts and cancels out, so that the flow velocity is slower than others. confirmed. When FIG. 7C is compared with FIG. 1, it is clear that the site where much adhesion is observed and the site where turbulent energy is concentrated almost overlap.

  The mechanism by which solids agglomerate and deposit from the state where fine particles of solid inclusions are dispersed in liquid molten steel has been extensively studied. Collision and aggregation are considered to be the dominant factors in the process. In other words, it can be said that the inclusions in the molten steel are likely to agglomerate at the site where the turbulent energy is concentrated, and the adhesion proceeds by the accumulation of the agglomerated inclusions. There is no contradiction between this and the result of the fact that the part where the submerged nozzle is frequently attached and the part where the turbulent energy is concentrated by the CFD calculation are overlapped.

  From the above, it can be said that the turbulent energy concentration site is likely to adhere, in other words, the cross-sectional shape of the discharge hole path that can suppress the turbulent energy concentration reduces the adhesion at the same position. I thought it could be a shape that could be done. From such a viewpoint, the present invention has been achieved by repeatedly performing CFD calculation on the structure around the discharge hole path of the immersion nozzle and confirming the result with an actual machine.

  FIG. 2 shows an immersion nozzle 1 according to the present invention. The immersion nozzle 1 has a cylindrical nozzle body 2. The nozzle body 2 has a cylindrical flow passage 3 extending in the length direction and concentrically with the nozzle body 2. The flow passage 3 is closed at the end of the nozzle body 2 on the tip 2a side, and is open at the end of the nozzle body 2 on the other end 2b side. In FIG. 2, the nozzle body 2 and the flow passage 3 are each cylindrical, but may be elliptical. As shown in FIG. 3A, the closed end portion of the flow passage 3 is a conical end surface 3a whose apex is located on the distal end portion 2a side. As shown in FIG. 3B, which is an end view of a cross section taken along line IIIb-IIIb in FIG. 3A, one end of the nozzle body 2 communicates with the flow passage 3 and the other end is the nozzle body. Two discharge hole paths 4 are formed which are opened at the outer peripheral surface 2c of 2 and constitute discharge holes 5. Each discharge hole path 4 is inclined toward the distal end portion 2a from the one end toward the other end.

  As shown in FIG. 3 (c), which is an end view of a section obtained by cutting the discharge hole path 4 along a plane S1 parallel to the length direction of the nozzle body 2, the section of the discharge hole path 4 has three apexes A, B and C have a pentagonal shape that is located closer to the tip 2a than the other vertices E and F. Of the three vertices A, B, and C, the vertex A is located in the middle with respect to the direction perpendicular to the length direction of the nozzle body 2, and is located closer to the tip 2 a than the vertex B and vertex C. Since the cross-sectional shape of the discharge hole path 4 is such a shape composed of the vertices A, B, and C, the flow of the molten steel flowing down in the vicinity of the inner peripheral surface 3b of the flow path 3 can smoothly flow through the flow path 3. The direction can be changed in the direction toward the inside in the radial direction. The remaining two vertices E and F of the cross-sectional shape of the discharge hole path 4 are vertices with R.

  When an angle formed by a line segment connecting the vertex A and the vertex B and a line segment connecting the vertex A and the vertex C is α, 90 ° ≦ α <180 °, and more preferably 100 ° ≦ α <160 °. . When α is smaller than 90 °, it is difficult to secure an opening area necessary for maintaining the discharge amount, and by providing an acute angle, stress concentrates on the position, and at the start of casting. There is a problem that the risk of trouble such as cracking increases. On the other hand, when α is larger than 180 °, the flow of the molten steel flowing down in the vicinity of the inner peripheral surface 3b of the flow passage 3 cannot be changed in the direction toward the radially inner side of the flow passage 3, so that the turbulent energy Cannot concentrate.

  As shown in FIG. 3B, an imaginary line L extending in the length direction of the flow passage 3 through the center O of the circular cross section obtained by cutting the flow passage along a plane S <b> 2 perpendicular to the length direction of the flow passage 3. A point D is defined as an intersection between the end face 3a and the end face 3a. The point D includes each vertex A in the cross section of each surface S1 of each discharge hole path 4 and is located on the opposite side to the tip portion 2a with respect to a virtual plane P1 perpendicular to the virtual line L. Thereby, the flow of the molten steel colliding with the end surface 3a is smoothly introduced into the discharge hole path 4, and the concentration of turbulent energy generated by the collision between the flow of molten steel flowing down the flow passage 3 and the reverse flow with respect to the end surface 3a is suppressed. As a result, it is possible to suppress the adhesion of inclusions to the inner peripheral surface 3b around the discharge hole path 4. On the other hand, when the point D is positioned on the tip 2a side of the virtual plane P1, the periphery of the point D has a waterfall shape, so that a strong reversal flow is generated with respect to the end surface 3a, and the turbulent energy is concentrated. Can not be suppressed. Moreover, the discharge hole path | route 4 needs to incline monotonously toward the outer peripheral surface 2c from the internal peripheral surface 3b. For example, if there is a pole whose gradient changes in the middle of the discharge hole path 4, the flow of molten steel is disturbed at that position, which is not preferable.

  Assuming that the angle formed by the line connecting the vertex A and the point D and the virtual line L is β, 30 ° ≦ β <90 °, and more preferably 45 ° ≦ β ≦ 85 °. By setting the angle β within this range, it becomes possible to smoothly introduce the flow of molten steel flowing down the flow passage 3 into the discharge hole passage 4. If β is less than 30 °, since the inclination of the discharge hole path 4 is too large, the molten steel flows in a direction toward a deeper part of the mold, which is disadvantageous for the floating of inclusions and gas in the molten steel, As a result, the risk of slab quality defects due to their remaining in the slab increases.

  Further, as shown in FIG. 3C, the distance between the line segment connecting the vertex B and the vertex E and the line segment connecting the vertex C and the vertex F is a, and the line segment connecting the vertex E and the vertex F If the distance between and the vertex A is b, there is no special range for a and b, but the ratio a / b between a and b is in the range of 0.33 <a / b ≦ 2.0. It is preferable. When a / b is 0.33 or less, a suction flow is likely to occur at a transition portion from the flow passage 3 to the discharge hole route 4. When the suction flow is generated, the effect of the present invention may be lost. On the other hand, when a / b is 2.0 or more, a necessary opening area cannot be secured, and thus the characteristics of the present invention cannot be fully utilized. Further, it is not preferable to secure a necessary opening area because a becomes too large and the interval between the two discharge holes 5 and 5 becomes small, and the risk of breakage of the nozzle body 2 increases.

  Thus, in the molten steel flow that flows through the flow passage 3 of the submerged nozzle 1, the concentration of turbulent energy in the vicinity of the inner peripheral surface 3b of the flow passage 3 is suppressed. The inclusion of inclusions in the molten steel on the peripheral surface 3b can be suppressed.

  In this embodiment, the point D is located on the opposite side to the tip portion 2a with respect to the virtual plane P1, but is located on the virtual plane P1 like the immersion nozzle 1 ′ shown in FIG. Also good. In this case, β = 90 °. As a result, together with the range of β in the embodiment, the range of β in the immersion nozzle according to the present invention is 30 ° ≦ β ≦ 90 °.

  In this embodiment, in the cross-sectional shape by the surface S1 of the discharge hole path 4, the line segment connecting the vertex B and the vertex E and the line segment connecting the vertex C and the vertex F are parallel to the virtual line L, respectively. However, it may be inclined with respect to the virtual line L. In this case, the distance a (see FIG. 3C) between the two lines changes at the position in the length direction of the nozzle body 2, but the maximum distance between the two lines in the direction perpendicular to the virtual line L is a. And Further, the line segment connecting the vertex E and the vertex F is not necessarily a straight line, and may be a curved line or a shape obtained by connecting several line segments. In this embodiment, two discharge hole paths 4 are provided, but three or more discharge hole paths 4 may be provided.

  In this embodiment, nothing is specified as the material of the nozzle body 2, but there are no particular restrictions on the material. For example, the main raw materials are alumina-graphite, alumina-silica-graphite, magnesia-graphite, spinel-graphite, zirconia-graphite, calcium zirconate-graphite, metals, alloys, carbides, nitrides Further, a material composed of an additive amount of less than 5 wt% may be used by using boride as an additive.

  In the present invention, a combination with a submerged nozzle or a gas blowing technique from a refractory used above the submerged nozzle, or a material that hardly adheres to the inner peripheral surface of the flow passage may be combined. Specifically, materials such as alumina, alumina-silica, spinel, spinel-flux, alumina-flux, spinel-graphite, zircon, zirconia-graphite, calcium zirconate-graphite are flow paths. It can be applied to the inner peripheral surface of. Moreover, this invention is applicable in the operating conditions of a general slab continuous casting machine. That is, the throughput can be handled from 0.5 ton / min to 8 ton / min.

Next, the effect obtained by using the immersion nozzle 1 according to the present invention will be verified based on examples.
Examples 1 to 12 shown in Table 1 were prepared as immersion nozzles according to the present invention, and Comparative Examples 1 to 4 shown in Table 2 were prepared as immersion nozzles not corresponding to the present invention. The configuration of the immersion nozzle according to each of Examples 1 to 12 and Comparative Examples 1 to 4 is the same as the configuration of the immersion nozzle 1 described in the above embodiment, and the distances a and b and the angles α and β are the same. Values are as shown in Tables 1 and 2. The two discharge hole paths of each immersion nozzle are provided so that the respective discharge holes are point-symmetrical with respect to the length direction of the nozzle body.

1. Verification of the effect of the present invention by numerical analysis For numerical analysis, fluid analysis software “PHOENICS VR editor 2014” manufactured by CHAM was used. The parameters used for this numerical analysis are as follows.
-Number of calculation cells: Approximately 800,000 (varies depending on the model)
-Fluid: Molten steel (1560 ° C., density 7.8 g / cm ³ )

  Using the CFD program PHOENICS used in the CFD calculation of the embodiment, the inner diameter of the flow passage 3 of the immersion nozzle 1 is 70 mm, the throughput is 3 ton / min, and each of the conditions of Examples 1-12 and Comparative Examples 1-4 The value of the turbulent energy of the molten steel flow was calculated. The results are shown in Tables 1 and 2. It is preferable to keep the turbulent energy low because nozzle clogging due to inclusions is likely to occur at locations where the turbulent energy in the molten steel is high.

  In the case of the comparative example 1 corresponding to the immersion nozzle 100 shown in FIG. 7 cited as the prior art of this specification, turbulent energy concentrates in the vicinity of the inner peripheral surface 103b of the flow passage 103 as shown in FIG. An area occurs. On the other hand, in the case of Example 3, as shown in FIG. 5, it can be seen that no turbulent energy concentration occurs. Therefore, the maximum value of the turbulent energy in Comparative Example 1 was set as a reference (100), and the maximum value of the turbulent energy was similarly compared under the conditions of each Example and each Comparative Example. When the maximum value was 70 or less, it was defined that there was an effect of reducing turbulent energy, and when it was 50 or less, it was defined that the effect was greater.

  All of Examples 1 to 12 had an effect of reducing turbulent energy. On the other hand, the comparative example 1 became high turbulent energy. In Comparative Example 2, although the effect of reducing turbulent energy was to some extent, it was difficult to manufacture. Although the comparative example 3 is a case where α is 180 °, it cannot be said that the effect of reducing turbulent energy is sufficient. Comparative Example 4 is a case where β is set to 25 °. However, although there was an effect of reducing turbulent energy, the flow of molten steel flows in a direction toward a deeper portion of the mold, which is disadvantageous for the floating of inclusions and gas. I was caught in.

  Next, the relationship between the throughput and the turbulent energy of the molten steel flow was calculated for each of the immersion nozzle of Example 3 and the immersion nozzle of Comparative Example 1. The results are shown in Table 3.

  When the throughput increases, the passage speed of the molten steel flow flowing down the flow path of the immersion nozzle increases, so that the turbulent energy of the molten steel flow also tends to increase. In Example 3 as well, the turbulent energy of the molten steel flow tended to increase as the throughput increased, but was suppressed more than Comparative Example 1 under the same throughput conditions.

2. Verification by continuous casting The actual machine was used for each of the immersion nozzle of Example 3 and the immersion nozzle of Comparative Example 1. The steel type was low-carbon Al killed steel, and these immersion nozzles were attached as respective dip tubes of a two-strand continuous casting machine. The inner diameter of the flow path of each immersion nozzle was 70 mm, and the throughput was 3 ton / min. FIG. 6 shows the result of comparison of the amount of alumina inclusions in the flow passage. The amount of adhesion was shown as an index with the amount of adhesion of Comparative Product 1 as 100. In Comparative Example 1, large adhesion occurred on the inner peripheral surface of the flow passage, whereas in Example 3, the adhesion amount decreased to 1/5 or less. Thus, the superiority of the present invention is clear.

  1, 1 'immersion nozzle, 2 nozzle body, 2a tip (nozzle body) tip, 2c (nozzle body) outer peripheral surface, 3 flow passage, 3a (flow passage) end surface, 3b (with flow) inner peripheral surface 4, discharge hole path, 5 discharge hole, L imaginary line, P1 imaginary plane, S1, S2 plane.

An immersion nozzle according to the present invention includes a nozzle body, a cylindrical or elliptical column-shaped flow passage provided in the nozzle body so as to extend in the length direction, one end communicating with the flow passage, and the other end And at least two discharge hole paths having discharge holes opened on the outer peripheral surface of the nozzle body, and the cross section of the discharge hole path cut by a surface parallel to the length direction of the nozzle body has three vertices at the other two points. It has a pentagonal shape that is located closer to the tip of the nozzle body than the vertex, and of the three vertices, the middle vertex in the direction perpendicular to the length direction of the nozzle body is designated as vertex A, and the remaining two vertices Assuming that vertex B and vertex C are located, vertex A is positioned closer to the tip of the nozzle body than vertex B and vertex C, and a line segment connecting vertex A and vertex B and a line segment connecting vertex A and vertex C are If the angle formed is α, 90 ° ≦ α < Is 80 °, the flow passage has an end face and closed at the tip end of the nozzle body, the center of the cross section of a circular shape or an elliptical shape by cutting the flow passage in a plane perpendicular to the length direction of the flow passage Assuming that an intersection of an imaginary line extending in the length direction of the flow passage and the end face is a point D, the point D includes the vertex A in the cross section of each discharge hole path and is perpendicular to the length direction of the nozzle body It is located on the virtual plane or on the opposite side of the tip end of the nozzle body with respect to the virtual plane.
If the angle formed by the line segment connecting the vertex A and the point D and the virtual line is β, 30 ° ≦ β ≦ 90 ° may be satisfied.

Claims (2)

A nozzle body;
A cylindrical or elliptical column-shaped flow passage provided in the nozzle body so as to extend in the length direction thereof;
And at least two discharge hole paths having one end communicating with the flow passage and the other end having discharge holes opened on the outer peripheral surface of the nozzle body,
The cross section obtained by cutting the discharge hole path with a plane parallel to the length direction of the nozzle body has a pentagonal shape in which three vertices are located closer to the tip end side of the nozzle body than the other two vertices, Of the three vertices, if the middle vertex in the direction perpendicular to the length direction of the nozzle body is the vertex A and the remaining two vertices are the vertex B and the vertex C, the vertex A is the vertex B and If the angle formed between the line segment connecting the vertex A and the vertex C and the line segment connecting the vertex A and the vertex C, which is located closer to the tip end side of the nozzle body than the vertex C, is 90 ° ≦ α <180 °,
The flow passage has an end face that is closed on a tip end side of the nozzle body, and passes through the center of a circular cross section obtained by cutting the flow passage along a plane perpendicular to the length direction of the flow passage. When the intersection of the imaginary line extending in the length direction of the path and the end face is a point D, the point D includes the vertex A in the cross section of each discharge hole path and is in the length direction of the nozzle body. An immersion nozzle that is located on a vertical virtual plane or on the opposite side of the virtual body from the tip of the nozzle body.   2. The immersion nozzle according to claim 1, wherein an angle formed by a line segment connecting the vertex A and the point D and the imaginary line is 30 ° ≦ β ≦ 90 °.

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