Tundish for continuous casting, method for continuous casting of steel, and weir

Abstract

Provided is a tundish for continuous casting capable of improving the cleanliness of molten steel. The tundish for continuous casting is provided with a storage part for storing supplied molten steel. The accommodating part has one or more molten steel outlets through which the molten steel flows out, and a hollow cylindrical weir disposed on the upstream side of the molten steel with respect to the one or more molten steel outlets. The weir includes a bottom portion, a wall portion provided upright from the bottom portion, an eave portion provided at one end of the wall portion so as to cover a peripheral edge thereof and facing the bottom portion of the weir, and a gas supply portion for supplying an inert gas to an inner space surrounded by the wall portion and the bottom portion. The gas supply unit includes a porous part in which a plurality of pores are formed as a whole, a support part which supports the porous part and is provided on a wall part of the weir, and a pipe which is provided on the wall part of the weir between the support part and the bottom part of the weir and ejects the inert gas.

Description

Technical Field

[0001] The present invention relates to a tundish for continuous casting, a method for continuous casting of steel and a weir. Background Art

[0002] The production of steel materials is carried out as follows. That is, molten steel supplied from a ladle to a tundish is supplied to a mold and cast to form a cast billet. The cast billet is formed into a predetermined shape by a process such as rolling to form a steel material.

[0003] Inclusions such as Al2O3 in molten steel may cause defects in steel materials, so they are preferably separated and removed from the molten steel before casting. Specifically, in the tundish, inclusions contained in the molten steel are floated and separated.

[0004] Such a cleaning technology for removing inclusions from molten steel is indispensable for the production of high-quality steel materials, and therefore its improvement is sought. Conventionally, a weir is provided to separate the steel receiving area where molten steel is supplied to the tundish and the steel quasi-static area where molten steel is discharged from a discharge port provided at the bottom.

[0005] For example, in the weir described in Patent Document 1, a plurality of holes are formed on the bottom side of the tundish, which penetrate from the surface of the steel receiving area side to the surface of the steel quasi-static area side. Therefore, the movement of inclusions lighter than the molten steel is restricted by the weir. In addition, the molten steel moves from the steel receiving area side to the steel quasi-static area side through the holes of the weir.

[0006] In addition, in Patent Document 2, in addition to the weir described in Patent Document 1 being provided in the tundish, a rib protruding upward from the bottom of the tundish is provided on the steel quasi-static region side. Therefore, even if inclusions move from the hole of the weir to the steel quasi-static region side, their moving direction is changed upward by the rib. As a result, inclusions can also be floated on the steel receiving region side.

[0007] In addition, in Patent Document 3, in addition to the weir described in Patent Document 1 being provided in the tundish, an inert gas is supplied upward from the bottom of the tundish toward the steel quasi-static region side. Thus, even if inclusions move from the holes of the weir toward the steel quasi-static region side, the inclusions are floated by the inert gas.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 53-6231

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 10-216909

[0012] Patent Document 3: Japanese Patent Application Publication No. 2011-143449 Summary of the invention

[0013] Problems to be solved by the invention

[0014] Even when a weir is provided in the tundish as in Patent Document 1, inclusions may pass through the holes of the weir. If inclusions are discharged from the outlet of molten steel, there is a possibility that defects may be caused in the steel material.

[0015] In addition, regarding the use of ribs to float inclusions as in Patent Document 2, it is desired to float inclusions more effectively, and there is room for improvement. In addition, at the end of casting, steel mesh will remain between the ribs and the weir, so there is a problem of increased cost for handling the residual steel.

[0016] When an inert gas is used to float inclusions as in Patent Document 3, there is a problem that the volume ratio of the inert gas in the molten steel must be increased in order to obtain a sufficient floating effect. If the flow rate of the inert gas is increased to increase the volume ratio of the inert gas in the molten steel, the inclusions on the surface of the molten steel, that is, the tundish slag, may be drawn into the molten steel by the inert gas. If the tundish slag is drawn into the molten steel, the molten steel is contaminated, which may cause defects in the steel material.

[0017] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a tundish for continuous casting, a method for continuous casting of steel, and a weir capable of improving the cleanliness of molten steel.

[0018] Means for solving problems

[0019] In order to solve the above-mentioned problems, the present invention has the following features.

[0020] [1] A tundish for continuous casting, comprising a receiving portion for storing supplied molten steel, wherein:

[0021] The receiving portion includes one or more molten steel outflow ports for allowing the molten steel to flow out, and a hollow cylindrical weir disposed on the upstream side of the one or more molten steel outflow ports for allowing the molten steel to flow out.

[0022] The weir comprises:

[0023] bottom;

[0024] A wall portion, erected from the bottom portion;

[0025] an eaves portion provided at one end of the wall portion so as to cover the periphery and face the bottom of the weir; and

[0026] a gas supply unit for supplying an inert gas to an internal space surrounded by the wall and the bottom;

[0027] The gas supply unit comprises:

[0028] The porous portion has a plurality of pores formed throughout.

[0029] a supporting portion supporting the porous portion and provided on a wall portion of the weir; and

[0030] A pipe is provided in the wall portion of the weir between the support portion and the bottom portion of the weir and discharges the inert gas.

[0031] [2] The tundish for continuous casting according to [1], wherein:

[0032] The weir has a receiving chamber surrounded by the porous portion, the support portion, the wall portion of the weir, and the bottom portion of the weir.

[0033] The pipe is provided on the wall portion surrounding the weir of the storage chamber.

[0034] [3] The tundish for continuous casting according to [1] or [2], wherein:

[0035] The gas supply unit includes an adjustment unit that adjusts a flow rate of the inert gas supplied from the pipe.

[0036] [4] The tundish for continuous casting according to any one of [1] to [3], wherein

[0037] The pipe is arranged along the wall of the housing portion and is covered with a fire-resistant covering material.

[0038] [5] A method for continuous casting of steel, using the tundish for continuous casting described in any one of [1] to [4], wherein:

[0039] The continuous casting method of steel includes a step of injecting an inert gas at a flow rate satisfying the following formula (1).

[0040] 0.02≤R≤1.00 (1)

[0041] R: flow rate of inert gas per unit area of ​​the porous portion [NL / (s×m 2 )]

[0042] [6] A weir provided in a tundish for continuous casting and formed in a hollow cylindrical shape, wherein:

[0043] The weir comprises:

[0044] bottom;

[0045] A wall portion, erected from the bottom portion;

[0046] an eaves portion provided at one end of the wall portion so as to cover the periphery and face the bottom of the weir; and

[0047] a gas supply unit for supplying an inert gas to an internal space surrounded by the wall and the bottom;

[0048] The gas supply unit comprises:

[0049] The porous portion has a plurality of pores formed throughout.

[0050] a supporting portion supporting the porous portion and disposed on the wall portion; and

[0051] A pipe is provided in the wall portion between the support portion and the bottom portion and discharges the inert gas.

[0052] [7] The weir according to [6], wherein:

[0053] The weir has a receiving chamber surrounded by the porous portion, the support portion, the wall portion of the weir, and the bottom portion of the weir.

[0054] The pipe is provided on the wall portion surrounding the weir of the storage chamber.

[0055] [8] The weir according to [6] or [7], wherein:

[0056] The gas supply unit includes an adjustment unit that adjusts a flow rate of the inert gas supplied from the pipe.

[0057] Effects of the Invention

[0058] According to the present invention, by supplying the inert gas through the porous portion, fine bubbles of the inert gas can be supplied to the molten steel injection area. As a result, the volume ratio of the inert gas in the molten steel can be increased, and inclusions contained in the molten steel injected from the ladle into the tundish can be efficiently floated. Thus, the cleanliness of the molten steel can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is an explanatory diagram showing the structure of a tundish for continuous casting.

[0060] Figure 2 This is an explanatory diagram showing a side view of a tundish for continuous casting.

[0061] Figure 3 It is shown Figure 1 An illustration of the structure of a weir.

[0062] Figure 4 yes Figure 3 Top view of the weir.

[0063] Figure 5 This is an explanatory diagram showing a scheme in which piping is provided.

[0064] Figure 6 This is an explanatory diagram showing another embodiment in which piping is provided.

[0065] Figure 7 It is a graph showing the relationship between the gas flow rate per unit area and the number density of inclusions.

[0066] Figure 8 It is a graph showing the number density of inclusions in the conventional example and the present invention. DETAILED DESCRIPTION

[0067] Figure 1 It is an explanatory diagram showing the structure of a tundish for continuous casting. Figure 2 1 is an explanatory diagram showing the side of a tundish for continuous casting. Figure 1 As shown, a tundish 100 for continuous casting is arranged between a ladle (not shown) storing molten steel MS and a mold 30 for cooling the molten steel MS.

[0068] like Figure 1 and 2 As shown, a tundish for continuous casting (hereinafter referred to as tundish) 100 has a box-shaped receiving portion 10 with an upper opening and a bottom. In this embodiment, the receiving portion 10 of the tundish for continuous casting 100 is formed in an inverted frustum shape with an upper bottom formed longer than a lower bottom.

[0069] The receiving portion 10 has a molten steel injection area AR1 for receiving the molten steel MS from the nozzle N1 of the ladle. The molten steel injection area AR1 is formed along the axis AX of the nozzle N1. In other words, the molten steel injection area AR1 is formed extending from the top of the nozzle N1 along the axis AX of the nozzle N1. The molten steel injection area AR1 is an area that has an expansion in the circumferential direction of the axis AX of the nozzle N1.

[0070] The receiving portion 10 has one or more molten steel outflow ports 11 for allowing the molten steel MS to flow out to the casting mold. Figure 1 As shown, in the present embodiment, the molten steel outlet ports 11 are formed at one end side and the other end side in the left-right direction in the bottom portion 12 of the tundish 100 .

[0071] The housing portion 10 has a weir 20 disposed between the molten steel pouring area AR1 and the molten steel outlet 11. The weir 20 is disposed on the upstream side of the molten steel MS relative to the molten steel outlet 11. The weir 20 is formed in a hollow bottomed cylindrical shape.

[0072] The weir 20 includes a wall portion 21 formed so as to surround the molten steel injection area AR1 and a bottom portion 22 provided at one end, that is, the lower end side, of the wall portion 21. In other words, the wall portion 21 is provided to stand upright from the bottom portion 22. The bottom portion 22 is provided to face the bottom portion 12 of the tundish 100 and to be in contact with the bottom portion 12.

[0073] The side cross section of the weir 20 is formed in a substantially U-shape. The weir 20 has an internal space 20a surrounded by a wall portion 21 and a bottom portion 22. A part of the molten steel pouring area AR1 is accommodated in the internal space 20a of the weir 20.

[0074] Each molten steel outlet 11 is provided with a nozzle N2 that connects the tundish 100 and the mold 30. Molten steel MS is supplied from the molten steel outlet 11 to the mold 30 via the nozzle N2. Molten steel MS is cooled by the mold 30 to form a cast billet 40.

[0075] Figure 3 It is an explanatory diagram showing the structure of the weir 20 . Figure 4 FIG. 2 shows a top view of the weir 20. Figure 3 and 4 As shown, the weir 20 has an eaves portion 23 provided at the other end, that is, the upper end, of the wall portion 21 so as to cover the periphery thereof and to face the bottom portion 22 .

[0076] The shape of the flange 23 is not particularly limited, but is preferably formed to protrude toward the molten steel pouring area AR1. In the present embodiment, the flange 23 is formed to extend in a direction parallel to the bottom 22 (eg, horizontal direction) toward the molten steel pouring area AR1.

[0077] The weir 20 has a gas supply portion 24 that supplies inert gas toward the molten steel injection area AR1 from above the bottom 22. The gas supply portion 24 is provided below the eaves portion 23. In other words, the gas supply portion 24 supplies inert gas to the internal space from above the bottom 22. A portion of the inert gas supplied from the gas supply portion 24 contacts the eaves portion 23 and rises.

[0078] The gas supply unit 24 includes a porous unit 25 having a plurality of fine pores 25a formed throughout and a support unit 26 supporting the porous unit 25. The gas supply unit 24 also includes a pipe 27 provided in the wall 21 between the porous unit 25 and the bottom 22 and ejecting the inert gas GS.

[0079] The porous part 25 is formed by a refractory material that is a ceramic. As such a refractory material, for example, a refractory material formed by mixing and sintering one or more of refractory inorganic particles selected from alumina, silica, etc. It should be noted that, as a refractory material, a refractory material composed mainly of alumina is particularly preferred.

[0080] The porous portion 25 can be produced by using spherical particles mainly composed of alumina as aggregates and firing them at 1600° C. or higher. The porous portion 25 can be produced, for example, by casting a dense castable refractory.

[0081] By using spherical particles as aggregates, the pores 25a of the porous portion 25 can be formed. The pores 25a of the porous portion 25 are not particularly limited, but for example, the average pore size measured by mercury penetration can be formed to be 10 to 40 μm. By forming the pores 25a in this way, the bubbles of the inert gas supplied from the porous portion 25 can be made small. That is, when the inert gas is supplied using the conventional method, the diameter of the bubble is about 100 μm, but by supplying the inert gas in this way, the diameter of the bubble can be made about 1 / 10 to 1 / 20 of the conventional diameter. In addition, by making the pores 25a of the porous portion 25 10 to 40 μm, the flow rate of the inert gas can be appropriately controlled.

[0082] The shape of the porous portion 25 is not particularly limited, but in this embodiment, it is formed into a plate shape. Figure 4 As shown, it is formed into a rectangle when viewed from above.

[0083] The support portion 26 is formed by a refractory material that is a ceramic. As such a refractory material, for example, a refractory material obtained by mixing and sintering one or more of refractory inorganic particles selected from alumina, silica, etc. It should be noted that, as a refractory material, a refractory material mainly composed of alumina is particularly preferred.

[0084] The support portion 26 is formed in a frame shape so as to support the edge of the bottom of the porous portion 25. The shape of the support portion 26 is not particularly limited, but in the present embodiment, it is formed in a rectangular frame shape when viewed from above. The support portion 26 is provided on the wall portion 21. The support portion 26 is fixed by, for example, fitting into a fitting recess (not shown) formed on the wall portion 21.

[0085] The weir 20 has a storage chamber 28 surrounded by the porous portion 25, the support portion 26, the wall portion 21, and the bottom portion 22. The wall portion 21 surrounding the storage chamber 28 is provided with a pipe 27.

[0086] It is preferable that the pipe 27 has fire resistance. Figure 5 The embodiment in which the pipe 27 is provided is shown. Figure 5 As shown, the pipe 27 is arranged along the wall 13 of the housing 10. In addition, the pipe 27 is covered by a fire-resistant coating material 50. As the coating material 50, for example, a prefabricated refractory can be cited. In addition, as the coating material 50, a prefabricated refractory and a repair material can also be used in combination. Figure 5In the example shown, a pre-refractory material 51 is disposed as the cladding material 50 disposed on the edge side of the housing portion 10. In addition, a repairing material 52 is disposed as the cladding material 50 disposed on the bottom 12 side of the tundish 100.

[0087] In addition, a pipe cover may be used as the covering material 50 . Figure 6 Another solution is shown in which a pipe 27 is provided. Figure 6 In the example shown, replace Figure 5 The prefabricated refractory described in the example shown in the figure is used as the pipe cover 53. In addition, a plurality of pipe covers 53 may be used. Figure 6 In the example shown, four pipe covers 53 are connected along the axial direction of the pipe 27 .

[0088] By configuring the piping 27 in this way, the construction of the refractory can be easily performed. In addition, the maintainability of the piping 27 can be improved compared to the case where the piping 27 is inserted from the bottom 12 of the tundish 100. In addition, since the processing for inserting the piping 27 with respect to the bottom 12 of the tundish 100 is not required, the leakage of molten steel from the bottom 12 can be suppressed.

[0089] It is preferable that an adjustment unit 29 for adjusting the flow rate of the inert gas is provided in the pipe 27. A valve can be used as the adjustment unit 29. The adjustment unit 29 may be manually operated or the opening degree may be adjusted by a control unit (not shown).

[0090] The inert gas supplied from the pipe 27 is introduced into the receiving chamber 28. When the inert gas is introduced into the receiving chamber 28, the pressure based on the inert gas is uniformly applied to the surface of the porous portion 25 that faces the bottom 22. As a result, the inert gas is supplied from the receiving chamber 28 to the molten steel injection area AR1 through the pores 25a of the porous portion 25. By supplying the inert gas in this way, the deviation of the supply method of the inert gas can be suppressed. It should be noted that the inert gas is not particularly limited, but Ar, N2, CO2, etc. can be cited.

[0091] It should be noted that in the present embodiment, the inert gas is supplied from the storage chamber 28 to the porous portion 25. However, the inert gas may be supplied to the porous portion 25 without passing through the storage chamber 28. For example, an attachment (not shown) capable of covering the surface on the bottom 22 side of the porous portion 25 may be installed on the pipe 27 for implementation.

[0092] The continuous casting method of steel includes a process of supplying molten steel MS from a nozzle N1 connected to a ladle (not shown) to a tundish 100, a process of removing inclusions contained in the molten steel MS in the tundish 100, a process of allowing the molten steel MS to flow from a molten steel outlet 11 of the tundish 100 to a mold 30, and a process of cooling the molten steel MS in the mold 30 to produce a cast billet.

[0093] The step of removing inclusions contained in the molten steel MS in the tundish 100 includes a step of injecting an inert gas at a flow rate satisfying the following formula (1).

[0094] 0.02≤R≤1.0 (1)

[0095] R: flow rate of inert gas per unit area of ​​the porous portion [NL / (s×m 2 )]

[0096] The gas flow rate (R) per unit area of ​​the porous portion 25 is preferably 0.02 to 1.00 NL / (s×m 2 ) is supplied from the gas supply unit 24, preferably at 0.20 to 1.00 NL / (s×m 2 It should be noted that the gas flow rate (R) per unit area of ​​the porous portion 25 can be adjusted by the adjustment unit 29.

[0097] The gas flow rate (R) per unit area passing through the porous portion 25 is 0.02 NL / (s×m 2 ) or above, it is possible to promote the floating of inclusions in the molten steel MS.

[0098] The gas flow rate (R) per unit area passing through the porous portion 25 is 1.00 NL / (s×m 2 ) or less, the entrapment of tundish slag can be prevented. In addition, by blowing inert gas at such a high flow rate, the bubble diameter of the inert gas can be made finer. This can promote the floating of inclusions and inhibit the inclusions from being entrapped in the molten steel.

[0099] As described above, according to the tundish 100 of the present invention, fine bubbles of inert gas can be supplied to the molten steel injection area AR1 by supplying the inert gas through the porous portion 25. As a result, the volume ratio of the inert gas in the molten steel MS can be increased, and inclusions contained in the molten steel injected from the ladle into the tundish 100 can be efficiently floated.

[0100] In addition, the flow rate of the molten steel MS in the molten steel injection area AR1 of the weir 20 is faster than the flow rate of the molten steel MS in other areas. Therefore, by supplying the inert gas toward the molten steel injection area AR1, the frequency of contact between the bubbles of the inert gas can be increased. As a result, the bubbles of the inert gas can be made smaller. Thus, the volume ratio of the inert gas in the molten steel MS can be further increased.

[0101] Therefore, according to the tundish 100 of the present invention, the floating effect of inclusions can be increased. In addition, since inclusions can be floated with a smaller flow rate of the inert gas, the entrapment of slag in the tundish 100 can be suppressed.

[0102] When the molten steel MS supplied from the nozzle N1 reaches the bottom 22 of the weir 20, it moves in a manner of spreading in the circumferential direction of the axis AX of the nozzle N1. When the molten steel MS reaches the wall 21 of the weir 20, it is pushed upward by the molten steel MS supplied next. When the molten steel MS reaches the flange 23, it moves toward the center of the axis AX of the nozzle N1, that is, the molten steel injection area AR1.

[0103] At the center of the axis AX of the nozzle N1, that is, the center of the molten steel pouring area AR1, the vectors of the molten steel MS in various directions cancel each other out. As a result, the moving speed of the molten steel MS is reduced.

[0104] Thus, the generation of the so-called short-circuit flow in which the molten steel MS flows directly from the molten steel injection area AR1 to the molten steel outlet 11 can be suppressed. Therefore, most of the molten steel MS can be moved above the weir 20. As a result, the inclusions can be caused to float and separate from the molten steel MS. Thus, the amount of inclusions flowing out from the molten steel outlet 11 to the mold 30 can be reduced. In particular, according to the tundish 100 of the present invention, the bubbles of the inert gas can be made finer than conventional bubbles. The fine bubbles can further enhance the floating effect of the inclusions. In this way, according to the tundish 100 of the present invention, the inclusions can be efficiently floated, and the inclusions can be suppressed from being drawn into the molten steel, so that high-cleanliness steel can be manufactured.

[0105] Example

[0106] (Test Example 1: Inclusion Measurement Test)

[0107] (Sample)

[0108] 300 tons of molten steel that had been subjected to oxygen blowing in a converter and RH vacuum degassing was used. The molten steel was supplied from a ladle to a tundish.

[0109] (Continuous Casting)

[0110] Continuous casting was performed using Ar as the inert gas blown from the weir. Specifically, a number of tests were performed by changing the flow rate (R) of the inert gas per unit area of ​​the porous portion. (R: flow rate of the inert gas per unit area of ​​the porous portion [NL / (s×m 2 )])

[0111] (Determination of the number of inclusions)

[0112] The number of inclusions in the slabs produced by continuous casting was measured by ultrasonic flaw detection. Inclusions with a diameter of 10 μm or more were measured. 2 The number of inclusions is calculated as the density.

[0113] exist Figure 7 The relationship between the flow rate (R) of the inert gas per unit area of ​​the porous portion and the density of inclusions in the slab is shown in FIG. Figure 7 As shown, when the flow rate (R) of the inert gas is lower than 0.02, the density of inclusions is higher than that of other conditions.

[0114] When the flow rate (R) of the inert gas is 0.02 to 1.00, the density of inclusions is lower than that of other conditions. When the flow rate (R) of the inert gas exceeds 1.00, the density of inclusions is lower than that of the condition where the inert gas is not supplied. In addition, under this condition, the density of inclusions is higher than that of the condition where the flow rate (R) of the inert gas is 1.00 or less.

[0115] It is considered that when the flow rate (R) of the inert gas is lower than 0.02, the effect of floating the inclusions in the tundish cannot be fully obtained under this condition. Therefore, it is considered that under this condition, the density of the inclusions is high.

[0116] In addition, it is considered that when the flow rate (R) of the inert gas exceeds 1.00, the tundish slag (inclusions) is drawn into the molten steel by the inert gas. Therefore, it is considered that under this condition, the density of inclusions is higher than when the flow rate (R) of the inert gas is 0.02 to 1.00.

[0117] (Test Example 2: Inclusion Measurement Test)

[0118] (Sample)

[0119] The same molten steel as that in Test Example 1 was used.

[0120] (Continuous Casting)

[0121] Continuous casting was performed using the tundishes of the prior art examples and the inventive examples (inventive examples 1 to 8). In addition, Ar was used as the inert gas blown into each tundish. Specifically, in the prior art examples, the inert gas was supplied toward the molten steel injection area without providing a weir in the tundish.

[0122] In addition, regarding the invention examples, a weir was provided and an inert gas was supplied from the weir toward the molten steel injection area. Regarding the invention examples (the present inventions 1 to 8), the flow rate of the inert gas supplied from the gas supply portion of the weir was changed. The flow rate of the inert gas for each invention example is shown in Table 1.

[0123]

[0124] R: flow rate of inert gas per unit area of ​​the porous portion [NL / (s×m 2 )]

[0125] (Determination of the number of inclusions)

[0126] The same method as in Test Example 1 was used.

[0127] Figure 8 The density of inclusions in the prior art examples and invention examples 1 to 8 is shown. Figure 8 As shown, it can be seen that the density of inclusions in the slabs in the present inventions 1 to 8 is significantly lower than that in the prior art. In particular, in the present inventions 1 to 5, the flow rate (R) of the inert gas is 0.02 to 1.00, so better results than those in the present inventions 6 to 8 are obtained.

[0128] Description of Reference Numerals

[0129] 100 Tundish

[0130] 10 Containment Division

[0131] 11 Molten steel outlet

[0132] 20 Weir

[0133] 20a Interior Space

[0134] 21 Wall

[0135] 22 Bottom

[0136] 23 Eaves

[0137] 24 Gas supply unit

[0138] 25 porous part

[0139] 26 Support

[0140] 27 Piping

[0141] 28 Containment Chamber

[0142] 29 Adjustment unit

[0143] AR1 Molten steel injection area

[0144] MS molten steel.

Claims

1. A tundish for continuous casting, comprising a receiving portion for storing supplied molten steel, wherein: The receiving portion includes one or more molten steel outflow ports for allowing the molten steel to flow out, and a hollow cylindrical weir disposed upstream of the one or more molten steel outflow ports. The weir comprises: bottom; A wall portion, erected from the bottom portion; an eaves portion provided at one end of the wall portion so as to cover the periphery and face the bottom of the weir; and a gas supply unit for supplying an inert gas to an internal space surrounded by the wall and the bottom; The gas supply unit comprises: The porous portion has a plurality of pores formed throughout. a supporting portion supporting the porous portion and provided on a wall portion of the weir; and A pipe is provided in the wall portion of the weir between the support portion and the bottom portion of the weir and discharges the inert gas.

2. The tundish for continuous casting according to claim 1, wherein: The weir has a receiving chamber surrounded by the porous portion, the support portion, the wall portion of the weir, and the bottom portion of the weir. The pipe is provided on the wall portion surrounding the weir of the storage chamber.

3. The tundish for continuous casting according to claim 1 or 2, wherein: The gas supply unit includes an adjustment unit that adjusts a flow rate of the inert gas supplied from the pipe.

4. The tundish for continuous casting according to claim 1 or 2, wherein: The pipe is arranged along the wall of the housing portion and is covered with a fire-resistant covering material.

5. The tundish for continuous casting according to claim 3, wherein: The pipe is arranged along the wall of the housing portion and is covered with a fire-resistant covering material.

6. A method for continuous casting of steel, using the tundish for continuous casting according to claim 1 or 2, wherein: The continuous casting method of steel includes the step of blowing the inert gas at a flow rate satisfying the following formula (1), 0.02≤R≤1.00 (1) R: flow rate of inert gas per unit area of ​​the porous portion [NL / (s×m 2 )].

7. A method for continuous casting of steel, using the tundish for continuous casting according to claim 3, wherein: The continuous casting method of steel includes the step of blowing the inert gas at a flow rate satisfying the following formula (1), 0.02≤R≤1.00 (1) R: flow rate of inert gas per unit area of ​​the porous portion [NL / (s×m 2 )].

8. A method for continuous casting of steel, using the tundish for continuous casting according to claim 4, wherein: The continuous casting method of steel includes the step of blowing the inert gas at a flow rate satisfying the following formula (1), 0.02≤R≤1.00 (1) R: flow rate of inert gas per unit area of ​​the porous portion [NL / (s×m 2 )].

9. A method for continuous casting of steel, using the tundish for continuous casting according to claim 5, wherein: The continuous casting method of steel includes the step of blowing the inert gas at a flow rate satisfying the following formula (1), 0.02≤R≤1.00 (1) R: flow rate of inert gas per unit area of ​​the porous portion [NL / (s×m 2 )].

10. A weir provided in a tundish for continuous casting and formed in a hollow cylindrical shape, wherein: The weir comprises: bottom; A wall portion, erected from the bottom portion; an eaves portion provided at one end of the wall portion so as to cover the periphery and face the bottom of the weir; and a gas supply unit for supplying an inert gas to an internal space surrounded by the wall and the bottom; The gas supply unit comprises: The porous portion has a plurality of pores formed throughout. a supporting portion supporting the porous portion and disposed on the wall portion; and A pipe is provided in the wall portion between the support portion and the bottom portion and discharges the inert gas.

11. A weir according to claim 10, wherein: The weir has a receiving chamber surrounded by the porous portion, the support portion, the wall portion of the weir, and the bottom portion of the weir. The pipe is provided on the wall portion surrounding the weir of the storage chamber.

12. A weir according to claim 10 or 11, wherein: The gas supply unit includes an adjustment unit that adjusts a flow rate of the inert gas supplied from the pipe.

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