JP2022157084A - sliding gate - Google Patents

Abstract

To provide a sliding gate which can improve manufacture easiness and durability in use while maintaining a turnability of a molten metal in a sliding gate used for the flow adjustment of the molten metal.SOLUTION: In addition to that a sliding surface channel axial direction 31 which projects a channel axial direction 10 on the sliding surface differs with plates each other to vary in a clockwise direction or a counterclockwise direction toward the downstream, a channel hole 6 in each plate the area of an upstream side surface aperture 8u is larger than the area of a downstream side surface aperture 8d, forms a turning flow also in the channel hole 6 of the sliding plate 1 and in a downstream side injection pipe 11, and can improve manufacture easiness and durability in use since an upstream aperture center of gravity 9u and a downstream aperture center of gravity 9d are disposed at different positions, as viewed in a sliding surface vertical downstream direction 32.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding gate for adjusting the flow rate of molten metal in the process of pouring molten metal from a ladle into a tundish or from a tundish into a mold in continuous casting of molten metal such as steel. More particularly, it relates to a method of swirling a stream of molten metal using a sliding gate.

In continuous casting of molten metal such as steel, as shown in FIG. A sliding gate 1 is used to adjust the flow rate of the molten metal 21 during the injection process of each molten metal 21 . A sliding gate 1 usually consists of two or three plates 2 . FIG. 7 shows the case of three plates. Each plate 2 is provided with channel holes 6 through which the molten metal passes. Sliding is possible between contacting plates, one of which is provided movably along a sliding surface 30 and is called a slide plate 4 . The remaining plates 2 do not move relative to the ladle 14 or tundish 15 to which the sliding gate 1 is attached and are called fixed plates (upper fixed plate 3, lower fixed plate 5). By sliding the slide plate 4, the opening area of the opening portion, which is the overlap of the passage holes 6 between the adjacent plates, is adjusted, thereby adjusting the flow rate of the molten metal and opening and closing the sliding gate. It can be carried out. FIG. 7 shows a case where the aperture is fully open.

As shown in FIG. 1, an injection pipe 11 such as a long nozzle 12 is provided below the sliding gate 1 provided at the bottom of the ladle 14, and the molten metal flowing out from the sliding gate 1 is injected into the tundish 15. At this time, it is guided into the tundish via the flow path inside the injection tube 11 . Under the sliding gate 1 provided at the bottom of the tundish 15, an injection pipe 11 such as an immersion nozzle 13 is provided. It is led into the mold via internal channels.

The molten metal flowing out from the sliding gate 1 at the bottom of the ladle 14 already has a flow velocity toward the downstream side when it passes through the sliding gate, and the flow velocity of the molten metal further increases as it falls through the injection tube. The molten metal 21 poured into the tundish 15 forms a flow that passes through the bottom of the tundish at high speed, giving the opportunity for the non-metallic inclusions contained in the molten metal to float and separate sufficiently within the tundish. The non-metallic inclusions flow directly into the mold together with the molten metal, causing deterioration in the quality of the cast slab.

In the molten metal injection tube 11, when the molten metal flow inside is swirled, part of the kinetic energy of the flowing molten metal can be distributed to the swirling flow velocity, and the downward molten metal flow velocity can be reduced. As a result, it is known that the maximum flow velocity of the downward flow discharged from the injection pipe 11 into the tundish is reduced, and the turbulence of the flow in the tundish due to the discharged flow can be suppressed.

In the invention described in Patent Document 1, in a sliding gate used for adjusting the flow rate of molten metal, the channel axis inclination angle between the channel axis direction of the channel hole in each plate and the sliding surface vertical downstream direction is The flow channel is inclined at 5° or more and 75° or less, and the direction of the flow channel axis is projected onto the sliding surface. direction or counterclockwise direction. As a result, a swirl flow is formed in the passage hole of the sliding gate, and a swirl flow is also formed in the injection pipe on the downstream side of the sliding gate. becomes possible.

International publication WO2019/198745

According to the invention described in Patent Document 1, by devising the structure of the sliding gate disposed in the upper part of the injection pipe, a swirling flow of sufficient strength in the injection pipe for injecting molten metal is achieved with a compact and simple mechanism. , without increasing the risk of blockage of the flow path. On the other hand, in the sliding gate that imparts a swirling flow to the molten metal in the injection nozzle, as described in Patent Document 1, the swirlability of the molten metal is maintained, while the durability during use and the ease of manufacture are improved. It is requested that

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sliding gate that maintains swivelability of molten metal while improving ease of manufacture and durability during use.

That is, the gist of the present invention is as follows.
[1] A sliding gate used for adjusting the flow rate of molten metal, the sliding gate having a plurality of plates having passage holes through which the molten metal passes, at least one of the plates having A slide plate that can slide,
The channel holes in each plate form upstream surface openings on the upstream surface of the plate surface located upstream of the molten metal passing therethrough, and form upstream surface openings on the downstream surface located downstream of the surface of the plate. Forming the openings, the direction from the center of gravity of the upstream side surface openings to the center of gravity of the downstream side surface openings is defined as the channel axis direction,
In each plate, the area of the upstream side surface opening is larger than the area of the downstream side surface opening, and the flow path hole in each plate extends in the downstream direction perpendicular to the sliding surface of the plate (hereinafter referred to as "sliding surface perpendicular downstream direction"). ), the center of gravity of the upstream surface aperture and the center of gravity of the downstream surface aperture are arranged at different positions,
The angle between the vertical downstream direction of the sliding surface and the direction of the longest side wall line of the channel hole in the plate (hereinafter referred to as the "longest side wall line inclination angle α") is 5° or more and 75° or less,
The direction in which the channel axis direction is projected onto the sliding surface is called the sliding surface channel axis direction, and the direction in which the slide plate slides when the sliding gate is closed is called the sliding closing direction. The angle formed by the sliding surface flow path axis direction clockwise with respect to the closing direction when viewed in the sliding surface perpendicular downstream direction is called a flow path axis rotation angle θ (within a range of ±180 degrees). The axis line rotation angle θ differs between adjacent plates, and the θ of the plate on the most upstream side is θ ₁ , the θ of the plate one downstream of that is θ ₂ , and the θ of the plate one further downstream is θ Numbered in order from ₃ , and when the channel axis rotation angle difference Δθ _N = θ _N - θ _N+1 (N is an integer of 1 or more and up to the number of plates - 1), Δθ _N is all 10° or more and less than 170°, or both Δθ _N are greater than -170° and less than or equal to -10°.
However, the longest side wall line direction is the longest side wall of the channel hole in the cross section parallel to the sliding surface perpendicular downstream direction and including the graphic center of the upstream surface opening. It means the direction in which the sidewall line faces.
[2] The sliding gate according to [1], characterized in that the figure of the downstream side surface opening fits inside the figure of the upstream side surface opening when viewed in the downstream direction perpendicular to the sliding surface. .
[3] The sliding gate according to [1] or [2], characterized in that the number of plates forming the sliding gate is two or three and the number of slide plates is one.

The present invention relates to a sliding gate used for adjusting the flow rate of molten metal. Alternatively, in addition to changing in the counterclockwise direction, the channel holes in each plate have an area of the upstream surface opening larger than the area of the downstream surface opening, and when viewed in the downstream direction perpendicular to the sliding surface When the center of gravity of the upstream side surface aperture and the center of gravity of the figure of the downstream side surface aperture are arranged at different positions, a swirling flow is generated in the flow channel hole of the sliding gate and in the injection pipe on the downstream side. It is possible to improve the durability during use while forming.

Fig. 2 is a conceptual cross-sectional view showing the relationship between the ladle, tundish, mold and sliding gate of the continuous casting apparatus; FIG. 2 shows a sliding gate of the present invention, where (A) is an upper fixed plate, (B) is a slide plate, (C) is a plan view of a lower fixed plate, and (D) is a combination of a sliding gate and an injection tube. It is a front view, (E) is a view taken along line EE, and (F) is a sectional view taken along line FF. It is a diagram showing the flow in the sliding gate of the present invention, (A) is an AA arrow view, (B) is a BB arrow view, (C) is a CC arrow view, (D) is a front view of a combination of a sliding gate and an injection tube, and (E) is a EE arrow view. FIG. 2 shows a sliding gate of the present invention, where (A) is an upper fixing plate, (B) is a slide plate, (C) is a front view of a combination of the sliding gate and injection tube, and (D) is a DD arrow view. FIG. (E) is a cross-sectional view taken along line EE. FIG. 10 is a view showing a conventional sliding gate with a channel hole having an inclination, (A) is a plan view of the upper fixed plate, (B) is the slide plate, (C) is a plan view of the lower fixed plate, and (D) is the sliding gate. and an injection tube, (E) is an EE arrow view, and (F) is an FF arrow cross-sectional view. FIG. 10 is a diagram showing a sliding gate of a comparative example, in which (A) is an upper fixing plate, (B) is a sliding plate, (C) is a plan view of a lower fixing plate, and (D) is a combination of a sliding gate and an injection tube. A front view, and (E) is a view taken along line EE. FIG. 3 shows a conventional sliding gate, where (A) is an upper fixed plate, (B) is a slide plate, (C) is a plan view of a lower fixed plate, and (D) is a front view of a combination of a sliding gate and an injection tube. (E) is a view taken along line EE, and (F) is a sectional view taken along line FF.

The present invention will be described with reference to FIGS. 1 to 7. FIG.
The sliding gate 1 is used for the purpose of adjusting the flow rate of the molten metal 21 in the process of pouring the molten metal 21 from the ladle 14 to the tundish 15 or from the tundish 15 to the mold 16 in continuous casting of molten metal such as steel (Fig. 1). In the sliding gate 1 constructed by stacking two or three plates 2, each plate 2 is provided with a channel hole 6 (see FIG. 7). Slide the slide plate 4 of the plates constituting the sliding gate 1, and when the sliding gate 1 is "open" due to the overlapping of the flow passage holes 6 of each plate, the flow from the upstream side to the downstream side of the flow passage hole 6 Molten metal flows toward the side. A direction perpendicular to the sliding surface 30 of the plate 2 and directed to the downstream direction (sliding surface vertical downstream direction 32) is normally directed vertically downward from top to bottom. In the case of horizontal continuous casting, the sliding surface vertical downstream direction 32 is oriented horizontally. In the following, basically, the case where the sliding surface 30 is horizontal and the sliding surface vertical downstream direction 32 is vertically downward will be described as an example.

As the cross-sectional shape of the channel hole 6, a cylindrical shape having a perfectly circular cross section perpendicular to the axial direction is normally used. In the sliding gate 1 of the present invention, the channel hole 6 formed in the plate 2 is not limited to a cylindrical shape, and the axial direction of the channel hole may also change within the plate. do not have. Therefore, first, the axis of the channel hole 6 formed in the plate 2 is defined.

The passage hole 6 of the conventional sliding gate 1 will be described with reference to FIG. A sliding gate 1 in FIG. 7 has three plates 2, and consists of an upper fixed plate 3, a slide plate 4, and a lower fixed plate 5 from the upstream side. Each plate 2 has a cylindrical shape with a perfectly circular cross section, and is formed with a channel hole 6 whose axial direction is oriented in the direction perpendicular to the sliding surface 30 (vertical downstream direction 32 of the sliding surface). there is The upstream surface of each plate is called an upstream surface 7u, and the downstream surface is called a downstream surface 7d. A figure formed by the inner peripheral surface of the channel hole 6 on the upstream surface 7u is called an upstream surface opening 8u. Further, the figure formed by the inner peripheral surface of the channel hole 6 on the downstream surface 7d is called the downstream surface opening 8d. In the example shown in FIG. 7, the axis of the cylindrical shape of the channel hole 6 is perpendicular to the sliding surface, so in FIGS. overlaps with If the shapes of the upstream side surface opening 8u and the downstream side surface opening 8d are regarded as figures, respectively, the center of gravity of the figure can be defined. The graphic center of gravity of the upstream side surface opening 8u will be called the upstream hole center of gravity 9u, and the graphic center of gravity of the downstream side surface hole 8d will be called the downstream hole center of gravity 9d. In the example shown in FIG. 7, both the upstream surface openings 8u and the downstream surface openings 8d have a perfect circular shape, so the upstream opening gravity center 9u and the downstream opening gravity center 9d coincide with the centers of the perfect circles. ing. Next, a flow path axial direction 10 is defined as a direction that passes through the upstream hole center of gravity 9u and the downstream hole center of gravity 9d and faces the downstream side. In the example shown in FIG. 7, the channel axis direction 10 is the same as the slide surface perpendicular downstream direction 32 . In FIG. 7(F), the line depicted by the dashed line is the channel axis direction 10 .

Next, the passage hole 6 of the sliding gate 1 described in Patent Document 1 will be described with reference to FIG. A sliding gate 1 in FIG. 5 has three plates, and consists of an upper fixed plate 3, a slide plate 4, and a lower fixed plate 5 from the upstream side. Each plate has a channel hole 6 whose cross section perpendicular to the axial direction is a perfect circle and the axial direction of the cylinder (channel axis direction 10) is inclined from the sliding surface perpendicular downstream direction 32. is formed. The upper fixing plate 3 will be described as an example with reference to FIGS. 5(A) and 5(F). FIG. 5(F) is a cross-sectional view taken along line FF of FIG. 5(A). Since the axial direction of the cylinder and the sliding surface perpendicular downstream direction 32 are inclined, the upstream side surface opening 8u and the downstream side surface opening 8d are drawn at different positions in FIG. 5(A). The centroids of the figures of the upstream side surface opening 8u and the downstream side surface opening 8d are defined as an upstream opening centroid 9u and a downstream opening centroid 9d, respectively. Further, the channel axis direction 10 is determined so as to pass through the upstream hole center of gravity 9u and the downstream hole center of gravity 9d and face the downstream side. In FIG. 5(F), the line depicted by the dashed dotted line is the channel axial direction 10 . The angle between the downstream direction perpendicular to the sliding surface of the plate (sliding surface perpendicular downstream direction 32) and the channel axis direction 10 is defined as channel axis inclination angle β.

In the example shown in FIG. 7, the downstream surface opening 8d of the upper fixed plate 3 and the upstream surface opening 8u of the slide plate 4, the downstream surface opening 8d of the slide plate 4 and the upstream surface opening of the lower fixed plate 5 are shown. The sliding position of the slide plate 4 is determined so that the holes 8u are aligned with each other, that is, the sliding gate 1 is fully open (see FIG. 7(D)). In the sliding gate 1 shown in FIG. 7, the opening degree of the sliding gate 1 can be reduced by moving the slide plate 4 leftward in the figure. By further moving the position of the slide plate 4 to the left in the figure, the sliding gate 1 can be fully closed. The same applies to the example shown in FIG. FIG. 5 shows that the sliding gate 1 is fully open, the downstream surface opening 8d of the upper fixed plate 3 and the upstream surface opening 8u of the slide plate 4, the downstream surface opening 8d of the slide plate 4 and the lower fixing plate 5 The sliding position of the slide plate 4 is determined such that the upstream surface openings 8u are aligned with each other. Therefore, the direction in which the slide plate 4 slides when the sliding gate 1 is closed is hereinafter referred to as "sliding closing direction 33".

The sliding gate of the present invention, which is a characteristic feature of the invention described in Patent Document 1, is a slanted hole in which the direction in which the passage hole 6 faces is inclined, and the direction of the slanted hole projected on the sliding surface 30 is two or three. While maintaining the point of appropriately combining plates oriented in different directions, the channel holes in each plate have a shape in which the area of the upstream side surface opening 8u is larger than the area of the downstream side surface opening 8d. characterized by being The sliding gate of the present invention will be described below with reference to FIGS. 2 to 4. FIG.

A sliding gate 1 in FIG. 2 has three plates 2, and consists of an upper fixed plate 3, a slide plate 4, and a lower fixed plate 5 from the upstream side. Channel holes 6 are formed in each plate 2 .
Here, the "longest side wall line direction" is defined. The longest side wall line direction 34 is a cross section that is parallel to the sliding surface perpendicular downstream direction 32 and includes the graphic center of the upstream surface opening 8u (the upstream opening center of gravity 9u). In an elongated cross section, it means the direction in which the longest side wall line is directed. In the case of FIG. 2, FIG. 2(F) is a cross-sectional view of the cross section, in which the longest sidewall line direction 34 appears.
Further, a direction obtained by projecting the channel axial direction 10 onto the sliding surface is defined as a sliding surface channel axial direction 31 . In FIGS. 2A to 2C and 2F, the sliding surface flow path axial direction 31 is indicated by thin arrows. In addition, in FIGS. 2A to 2C, the sliding surface channel axial direction 31 overlaps the channel axial direction 10. As shown in FIG. In addition, in the example shown in FIG. 7, since the channel axis direction 10 faces the sliding surface perpendicular downstream direction 32, the sliding surface channel axis direction 31 does not appear in FIGS. .

The most important feature of the present invention is, firstly, in the channel holes in each plate, the opening area of the upstream surface openings 8u (upstream surface opening area) is equal to the opening area of the downstream surface openings 8d. (downstream side surface opening area), and when viewed in the downstream direction 32 perpendicular to the sliding surface, the figure center of gravity of the upstream side surface opening 8 u (upstream opening center of gravity 9 u) and the figure center of gravity of the downstream side surface opening 8 d ( The center of gravity of the downstream aperture 9d) is arranged at a different position.
The channel axis direction 10 can be determined so as to pass through the upstream hole center of gravity 9u and the downstream hole center of gravity 9d and face the downstream side (FIG. 2(F)). Here, the reason why the center of gravity of the opening is used to determine the flow path axis direction 10 instead of the center of the circle is that the flow path axis direction 10 is universally defined even when the shape of the opening is not a perfect circle. be.
As shown in FIGS. 2A to 2C, in all three plates 2, the opening area of the upstream surface openings 8u (upstream surface opening area) is greater than that of the downstream surface openings 8d. It has a shape larger than the pore area (downstream surface pore area). When viewed in the downstream direction 32 perpendicular to the sliding surface, the graphic center of the upstream surface opening 8u (upstream opening center of gravity 9u) and the graphic center of the downstream surface opening 8d (downstream opening center of gravity 9d) are different. are placed in the same position. Therefore, the direction from the upstream opening center of gravity 9u to the downstream opening center of gravity 9d (channel axis direction 10) has an angle with respect to the sliding surface vertical downstream direction 32, and the sliding surface channel axis direction 31 is formed. The Rukoto. FIG. 2(F) is a cross-sectional view taken along line FF of FIG. 2(A). The cross-sectional view corresponds to a cross-section that is parallel to the sliding surface perpendicular downstream direction 32 and includes both the upstream opening center of gravity 9u and the downstream opening center of gravity 9d. In the cross-sectional view, the downstream opening center of gravity 9d is located on the left side of the drawing with respect to the upstream opening center of gravity 9u, and the sliding surface flow path axis direction 31 is the direction from right to left in the drawing. there is The inclination of the side wall 36 on the right side of the drawing, which is the opposite direction to the sliding surface flow path axis direction 31, is gentle. The direction in which the right side wall faces in the sectional view of FIG. 2(F) corresponds to the "longest side wall line direction 34" defined above. On the other hand, the inclination of the side wall 36 on the left side of the drawing, which is the direction in which the sliding surface channel axis direction 31 is directed, is steeper than the inclination of the side wall on the right side. It is preferable that this slope is a steep slope that coincides with or is substantially close to the sliding surface vertical downstream direction 32 .

In the sliding gate described in Patent Document 1, since the flow path forms an oblique hole, as seen in FIG. is formed. When this sliding gate is used in continuous casting, the sharp edge may cause material loss, which shortens the life of the sliding gate.
In the sliding gate of the present invention, as described above, the opening area of the upstream surface openings 8u (upstream surface opening area) is equal to the opening area of the downstream surface openings 8d (downstream surface opening area). Larger, when viewed in the downstream direction perpendicular to the sliding surface, the graphic center of the upstream side surface opening and the graphic center of the downstream side surface opening are arranged at different positions. As a result, as is clear from FIG. 2(F), the slope of the side wall on the left side of the drawing, which is the direction in which the sliding surface flow channel axis direction 31 is directed, is steep, which coincides with or is substantially close to the vertical downstream direction of the sliding surface. slope. As a result, the left side wall of the flow path in FIG. 2(F) has a corner formed with the upstream surface 7u, which is not an acute angle but a right angle or an angle close to it. As a result, the acute angle portion 35u of the upstream surface 7u as seen in FIG. 5(F) is eliminated.

When the sliding gate of the present invention was used in continuous casting, the frequency of occurrence of material defects in the flow path of the sliding gate was reduced, and the durability during use was improved. As for the upstream surface 7u, the acute angle portion 35u in FIG. 5(F) has been eliminated as is clear from FIG. Furthermore, the effect of reducing the loss of material was also observed for the downstream surface 7d. As shown in FIG. 2(F), the acute angle portion 35d is not eliminated for the downstream surface 7d. Regarding the fact that the defect is reduced in spite of this, the angle formed by the side wall 36 of the channel hole 6 on the downstream surface 7d of each plate and the downstream surface 7d of the plate is It is presumed that fracture is less likely to occur because the change is small and the stress concentration is small.

A second feature of the present invention is that the angle between the vertical downstream direction 32 of the sliding surface and the longest side wall line direction 34 of the channel hole in the plate (the longest side wall line inclination angle α) is 5° or more and 75° or less. In addition, the angle formed by the sliding surface flow path axis direction 31 with respect to the sliding closing direction 33 clockwise when viewed in the sliding surface vertical downstream direction 32 is a flow path axis rotation angle θ (within a range of ±180 degrees) , and the channel _axis rotation angle _θ is different between adjacent plates. When the θ of the plate is numbered sequentially from θ ₃ , and Δθ _N = θ _N - θ _N+1 (N is an integer of 1 or more and up to the number of plates minus 1), the angle Δθ _N is all 10° or more. and less than 170°, or all the angles Δθ _N are more than −170° and less than or equal to −10°. Details will be described below.

The angle formed by the sliding surface channel axis direction 31 with respect to the sliding closing direction 33 clockwise when viewed in the sliding surface vertical downstream direction 32 is called a channel axis rotation angle θ. The channel axis rotation angle θ is defined as an angle in the range of ±180°. That is, when the sliding surface flow path axis direction 31 becomes an angle (θ') exceeding +180° clockwise when viewed in the sliding surface perpendicular downstream direction 32, "θ = θ' - 360°" Define the angle θ as a negative value. As a subscript of the angle θ, the θ of the most upstream plate is numbered as θ ₁ , the θ of the plate one downstream thereof is θ ₂ , and the θ of the plate one further downstream is θ ₃ . When θ _N is representatively expressed, N is an integer of 1 or more and means a numerical value up to the number of plates of the sliding gate 1−1. In the example shown in FIG. 2, the upper fixed plate 3 has an angle θ ₁ =−45°, the slide plate 4 has an angle θ ₂ =+90°, and the lower fixed plate 5 has an angle θ ₃ =−135°.

Furthermore, in the sliding gate 1, the relationship of the channel axis line rotation angle between two plates that are in contact with each other is defined as follows. That is, Δθ _N is determined as Δθ _N =θ _N -θ _N+1 . Δθ _N is defined as an angle in the range of ±180 degrees, like θ _N above. That is, when Δθ _N becomes an angle (Δθ _N ') exceeding +180°, Δθ _N is defined as a negative value by setting "Δθ _N =Δθ _N '-360°". Also, when Δθ _N becomes an angle (Δθ _N ') less than -180°, Δθ _N is defined as a positive value by setting "Δθ _N =Δθ _N '+360°". As a result, Δθ _N becomes a number within the range of ±180°. Here, when Δθ _N is more than 0° and less than +180°, it indicates that the channel axis line rotation angle θ _N changes counterclockwise from upstream to downstream. Conversely, when Δθ _N is more than −180° and less than 0°, it indicates that the channel axis rotation angle θ _N changes clockwise from upstream to downstream. In the example shown in FIG. 2, since Δθ ₁ =θ ₁ -θ ₂ =-135° and Δθ ₂ '=θ ₂ -θ ₃ =225°, Δθ ₂ =Δθ ₂ '-360°=-135° . Both Δθ ₁ and Δθ ₂ are within the range of -180° to 0°, indicating that the channel axis rotation angle changes clockwise.

Based on the above preparations, the conditions that the sliding gate 1 of the present invention should have and the reasons thereof will be described.

In the conventional sliding gate 1 as shown in FIG. 7, the flow path axis direction 10 is perpendicular to the sliding surface, that is, the flow path axis inclination angle β is 0° and has no inclination. On the other hand, the flow passage hole 6 in the plate of the present invention has an upstream surface opening area larger than the downstream surface opening area, and when viewed in the sliding surface perpendicular downstream direction 32, the upstream surface opening 8u is larger than the downstream surface opening area. It is characterized in that the graphic center of gravity (upstream aperture gravity center 9u) and the graphic gravity center of the downstream side surface aperture 8d (downstream aperture gravity center 9d) are arranged at different positions. As a result, coupled with the fact that the direction 34 of the longest side wall line of the channel hole 6 is inclined with respect to the downstream direction 32 perpendicular to the sliding surface, the molten metal flowing through the plate has only a velocity component in the downstream direction 32 perpendicular to the sliding surface. Instead, it has a velocity component perpendicular to the sliding surface vertical downstream direction 32 (horizontal velocity component in the case of normal continuous casting). In the present invention, the longest side wall line inclination angle α is 5° or more and 75° or less. By setting the angle α to 5° or more, the molten metal has a sufficient horizontal velocity component, which makes it possible to form a swirling flow in the injection pipe as described below. The angle α is preferably 15° or more, more preferably 25° or more. On the other hand, if the angle α is too large, it is not preferable from the viewpoint of ensuring the strength of the refractory and suppressing wear, so the angle α is set to 75° or less. The angle α is preferably 65° or less, more preferably 55° or less.

_Regarding the _{sliding gate 1} of the present invention shown in _FIG . Since it is more than -180° and less than 0°, it indicates that the channel axis rotation angle θ _N changes clockwise from upstream to downstream. The molten metal flowing through the channel holes 6 of the upper fixed plate 3 flows along the channel axial direction 10 of the upper fixed plate 3 as shown by the streamlines 18 in FIG. 3(A). At the contact surface between the upper fixed plate 3 and the slide plate 4 , the liquid flows downstream through the slide plate 4 from the downstream side surface opening 8 d (one-dot chain line in FIG. 3B ) of the upper fixed plate 3 . Inside the passage hole 6 of the slide plate 4, the molten metal flow flowing out from the downstream side surface opening 8d of the upper fixed plate 3 (one-dot chain line in FIG. 3(B)) is shown as a streamline in FIG. 3(B). As indicated by 18, a swirl flow is formed along the side wall 36 of the channel hole 6 of the slide plate 4, and the downstream side surface opening 8d of the slide plate 4 (solid line in FIG. 3 (C) with a dashed line), the water flows out further into the channel hole 6 of the lower fixing plate 5 . Inside the channel hole 6 of the lower fixed plate 5, a swirl flow is formed along the side wall 36 of the channel hole 6 of the lower fixed plate 5 as shown by the streamline 18 in FIG. It flows out into the injection pipe 11 on the downstream side from the downstream side surface opening 8d of the fixed plate 5, and as shown in FIGS. , moves downstream in the injection tube 11 .

When the conventional sliding gate 1 shown in FIG. 7 is used, all the kinetic energy of the molten metal flow when it flows out from the opening of the sliding gate 1 is spent on the flow velocity in the downstream direction. ing. On the other hand, when the sliding gate 1 of the present invention as shown in FIG. As compared with the conventional sliding gate 1 shown in FIG. 7, it is possible to suppress the flow velocity in the downstream direction. As a result, when the injection pipe 11 is the long nozzle 12, even when the molten metal flows out from the lower end of the injection pipe 11 into the molten metal 21 in the tundish 15, the swirling flow in the injection pipe 11 causes injection As a result of the presence of the radial component of the flow velocity from the lower end of the tube 11, the downward flow velocity from the lower end of the injection tube 11 can be suppressed.

It is the difference between the channel axis rotation angles θ _N of the adjacent plates to form a swirling flow in the flow channel hole 6 of the sliding gate 1 and also in the injection pipe downstream of the sliding gate. Conditions for the angle Δθ _N will be described. As mentioned above, Δθ _N is defined as an angle within ±180°. Here, if Δθ _N is more than −10° and less than +10°, the difference between the channel axis rotation angles θ _N and θ _N+1 is too small to form a swirling flow. On the other hand, when Δθ _N is +170° or more or −170° or less, the absolute value of Δθ _N is too large, which rather hinders the formation of swirling flow. If the sliding gate 1 has two plates, only Δθ ₁ is defined and it is sufficient if the Δθ ₁ satisfies the above conditions. In addition to Δθ ₁ , Δθ ₂ and even more Δθ _N are defined when the sliding gate 1 has three or more plates. All of the Δθ _N must be 10° or more and less than 170°, or all of the angles Δθ _N must be more than -170° and -10° or less. As a result, when the channel axis direction 10 of the first and second plates changes clockwise, the third and subsequent plates also change clockwise in the same way. When the channel axis direction 10 changes counterclockwise, the third and subsequent sheets also change counterclockwise, so that a swirling flow can be effectively formed within the sliding gate. A more preferable range of Δθ _N is 30° or more and less than 165°, or more than -165° and -30° or less.

When manufacturing the plate of the sliding gate, powdered graphite as a raw material is filled in a frame mold and molded. If the channel holes 6 of the plate 2 can also be formed by mold molding, production will be facilitated. In the sliding gate described in Patent Document 1, as shown in FIG. 5, the cylindrical flow path constitutes an oblique hole, so it is difficult to form this flow path by frame molding. . After forming a plate having no channels in a formwork, oblique hole channels are formed by drilling or cutting.
The sliding gate of the present invention is preferably characterized in that when viewed in the downstream direction 32 perpendicular to the sliding surface, the figure of the downstream side surface opening 8d fits inside the figure of the upstream side surface opening 8u. In this embodiment, when the plate 2 is placed horizontally with the upstream surface 7u facing upward, there is no overhanging portion on the side wall 36 of the channel hole 6. By filling the raw material into the mold after providing the 6 in the mold, the passage holes 6 are formed in the plate 2 when the molding of the mold is completed. Since there is no need for additional drilling or cutting to form the flow path, the production process is simplified, the production cost is reduced, and mass production can be carried out.

The number of plates forming the sliding gate 1 is preferably two or three. The examples shown in FIGS. 2 and 3 are for the case where the number of plates is three, as described above. In FIG. 4, the number of plates is two, and the first plate from the upstream side constitutes the upper fixed plate 3 and the second plate constitutes the slide plate 4 . α=53°, θ ₁ =−27°, θ ₂ =+27°, Δθ ₁ =−53°, and a clockwise swirling flow can be formed. The reason why it is preferable that the number of plates forming the sliding gate 1 is 2 or 3 is that at least 2 plates are required to develop the throttle mechanism of the sliding gate, and 4 or more plates are unnecessary for flow rate adjustment. This is because the cost increases as the number of plates increases.

Although the plates constituting the sliding gate 1 have the same thickness in the following examples and comparative examples, the thickness of each plate may be different, for example, the thickness of the slide plate 4 may be the thinnest. A preferable range for the thickness of the plate is 10 mm or more and 50 mm or less. In addition, in these examples and comparative examples, examples were shown in which the channel hole shapes of the inlet and outlet of each plate of the sliding gate were circles of the same size. It is possible to obtain a swirl flow as long as it satisfies the provisions of A preferred range for the upstream surface open area is 700 mm ² to 18000 mm ² .

Preferably, when the sliding gate is fully open, when viewed in the downstream direction 32 perpendicular to the sliding surface, the positions of the graphic centroids (upstream opening centroids 9u) of the upstream surface openings 8u of each plate are the same.

EXAMPLES The content of the present invention will be specifically described below with reference to examples.
FIG. 1 shows the configuration from a ladle 14 (ladle) to a mold 16 (mold) of a continuous casting machine for molten metal. In the examples, steel is assumed as the molten metal. When the present invention is applied to, for example, the sliding gate 1 of the ladle 14, a swirl flow is formed in the injection pipe 11 (long nozzle 12) connected to the downstream side of the sliding gate, and the molten steel in the tundish 15 from the lower end of the injection pipe 11. Effects such as reducing the maximum flow velocity of the discharged discharge flow, rectifying the flow in the tundish, and promoting the floating removal of non-metallic inclusions can be expected. The shape of the sliding gate 1 of the embodiment is illustrated below.

Here, the plates of the sliding gate 1 having three plates are called an upper fixed plate 3, a slide plate 4 and a lower fixed plate 5 in order from the top. In the case of the sliding gate 1 having two plates, they are the upper fixed plate 3 and the slide plate 4 in order from the top.

In the "upper and lower opening area difference" column of Table 1, the opening area of the upstream surface opening 8u (upstream surface opening area) is the opening area of the downstream surface opening 8d (downstream surface opening area ) is described as “large” when it has a larger shape (this invention), and “same” is described when both areas are equal (comparative example).

Regarding the longest side wall line inclination angle α (channel axis line inclination angle β in a comparative example in which the upper and lower opening area differences are “same”) and channel axis line rotation angle θ, subscripts 1, 1, 2 (, 3) are attached. Regarding the longest side wall line inclination angle α, the α of the most upstream plate is numbered as α ₁ , the α of the plate one downstream thereof is α ₂ , and the α of the plate further downstream is α ₃ . . The same applies to the channel axis line inclination angle β. Regarding the channel axis rotation angle θ, the θ of the most upstream plate is numbered θ ₁ , the θ of the plate one downstream is θ ₂ , and the θ of the plate one downstream is θ ₃ . .

For the ladle 14 and the tundish 15, an experiment using a water model experimental machine that is 1/1 of the actual machine and continuous casting with the actual machine were conducted to confirm the effects of the present invention.
Each plate 2 of the sliding gate 1 has a thickness of 35 mm, and the shape of the upstream surface 7u of the channel hole 6 formed in the plate 2 is a perfect circle with a diameter of 80 mm. The shape of the downstream surface 7d of the channel hole 6 is a perfect circle with a diameter of 51 mm when the upper and lower opening area difference is "large", and a perfect circle shape with a diameter of 80 mm when the upper and lower opening area difference is "same". is. The predetermined angles shown in Table 1 are used for the longest side wall line inclination angle α (the channel axis line inclination angle β in the comparative example in which the upper and lower opening area differences are the same) and the channel axis line rotation angle θ. A long nozzle 12 as an injection pipe 11 provided below the sliding gate 1 has an inner diameter of 100 mm, and the lower end of the long nozzle 12 is immersed in a tundish 15 .

In the water model experiment, the height from the water surface in the ladle 14 to the position of the sliding gate 1 is 3 m, the height from the sliding gate 1 at the bottom of the ladle 14 to the water surface in the tundish 15 is 1 m, and the slide plate 4 of the sliding gate 1 The position of was adjusted to 30 mm (from fully open to 50 mm closed), and while the water surface position in the tundish was held at a constant height, the water flowed out from the sliding gate in a steady state.
At the position of the lower end of the long nozzle 12, the flow velocity of water flowing out from the lower end of the long nozzle 12 into the tundish 15 was measured by the laser Doppler method for each flow direction. At the lower end position of the long nozzle 12, the "swirling flow evaluation result" is indicated by "O" when there is a horizontal flow velocity, and by "x" when there is no horizontal flow velocity.

A casting test was conducted in the actual continuous casting. Refractory wear was evaluated by collecting used refractories and evaluating the reusability of the refractories based on cracks and chips present on the refractory surface along the plate holes. If it can be reused without maintenance, it is evaluated as ◯, and if it can be reused after maintenance, it is evaluated as Δ.
The refractory manufacturability of the sliding gate was evaluated. When the flow path can be formed by manufacturing the mold, it is marked with ◯, and when manufacturing by drilling or cutting is required, it is marked with △.

In Example A of the present invention (see FIG. 2), the difference in upper and lower opening areas is "large", and the upper fixed plate 3 of the sliding gate 1 of the three-plate type has oblique holes of θ ₁ =-45°, the slide plate 4 has an oblique hole of θ ₂ =90°, and the lower fixing plate 5 has an oblique hole of θ ₃ =-135°. Table 1 shows the channel axis line inclination angles α ₁ to α ₃ . By this combination, even if the sliding gate 1 is fully open or throttled, a circumferential flow velocity is imparted to the molten metal flow, and a swirling flow is formed inside the flow path 17 of the injection pipe 11 attached below the sliding gate 1. can do. The swirl flow evaluation result was ◯. Both the refractory wear evaluation and the refractory manufacturability were evaluated as ◯.

In Example B of the present invention (see FIG. 4), the difference in upper and lower opening areas is "large", and the upper fixed plate 3 of the two-plate type sliding gate 1 has an oblique hole of θ ₁ =-27° and a slide plate. 4 has an oblique hole of θ ₂ =27°. Table 1 shows the channel axis line inclination angles α ₁ to α ₂ . Depending on the combination, whether the sliding gate 1 is fully open or throttled, the molten metal flow is given a circumferential flow velocity, and a swirling flow is formed inside the flow path 17 of the injection pipe 11 attached below the sliding gate 1. be able to. The swirl flow evaluation result was ◯. Both the refractory wear evaluation and the refractory manufacturability were evaluated as ◯.

In Comparative Example C (see FIG. 5), the upper and lower opening area differences are the same, and the upper fixed plate 3 of the sliding gate 1 of the three-plate type has oblique holes of θ ₁ =-45°, the slide plate 4 has an oblique hole of θ ₂ =90°, and the lower fixing plate 5 has an oblique hole of θ ₃ =-135°. Table 1 shows the channel axis line inclination angles α ₁ to α ₃ . By this combination, even if the sliding gate 1 is fully open or throttled, a circumferential flow velocity is imparted to the molten metal flow, and a swirling flow is formed inside the flow path 17 of the injection pipe 11 attached below the sliding gate 1. can do. The swirl flow evaluation result was ◯. Both the refractory wear evaluation and the refractory manufacturability were Δ.

In Comparative Example D (not shown), the upper and lower opening area differences are "same", the upper fixed plate 3 of the two-plate type sliding gate 1 has oblique holes of θ ₁ = -27°, the slide plate 4 has an oblique hole with θ ₂ =27°. Table 1 shows the channel axis line inclination angles α ₁ to α ₂ . Depending on the combination, whether the sliding gate 1 is fully open or throttled, the molten metal flow is given a circumferential flow velocity, and a swirling flow is formed inside the flow path 17 of the injection pipe 11 attached below the sliding gate 1. be able to. The swirl flow evaluation result was ◯. Both the refractory wear evaluation and the refractory manufacturability were Δ.

Comparative Example E (see FIG. 6) has a “large” upper and lower opening area difference and has a structure similar to that of Inventive Example A, but Δθ ₁ and Δθ ₂ are −170° or less and 170° or more, respectively. Therefore, it is an example in which turning cannot be obtained. The swirl flow evaluation result was x. Both the refractory wear evaluation and the refractory manufacturability were evaluated as ◯.
Comparative Example F (see FIG. 7) is a normal sliding gate in which the upper and lower opening area differences are "same" and the channel axis line inclination angles β are all 0°. The swirl flow evaluation result was x. Both the refractory wear evaluation and the refractory manufacturability were evaluated as ◯.

1 sliding gate 2 plate 3 upper fixed plate 4 slide plate 5 lower fixed plate 6 channel hole 7u upstream surface 7d downstream surface 8u upstream surface opening 8d downstream surface opening 9u upstream opening center of gravity 9d downstream opening center of gravity 10 Flow path axis direction 11 Injection pipe 12 Long nozzle 13 Submersion nozzle 14 Ladle 15 Tundish 16 Mold 17 Flow path 18 Stream line 21 Molten metal 30 Slide surface 31 Slide surface flow path axis direction 32 Slide surface vertical downstream direction 33 Sliding closing direction 34 Longest side wall line direction 35u Acute angle portion 35d Acute angle portion 36 Side wall α Maximum side wall line inclination angle β Channel axis line inclination angle θ Channel axis line rotation angle

Claims (3)

A sliding gate used for adjusting the flow rate of molten metal, the sliding gate having a plurality of plates having passage holes through which the molten metal passes, at least one of the plates being slidable. is a possible slide plate,
The channel holes in each plate form upstream surface openings on the upstream surface of the plate surface located upstream of the molten metal passing therethrough, and form upstream surface openings on the downstream surface located downstream of the surface of the plate. Forming the openings, the direction from the center of gravity of the upstream side surface openings to the center of gravity of the downstream side surface openings is defined as the channel axis direction,
In each plate, the area of the upstream side surface opening is larger than the area of the downstream side surface opening, and the flow path hole in each plate extends in the downstream direction perpendicular to the sliding surface of the plate (hereinafter referred to as "sliding surface perpendicular downstream direction"). ), the center of gravity of the upstream surface aperture and the center of gravity of the downstream surface aperture are arranged at different positions,
The angle between the vertical downstream direction of the sliding surface and the direction of the longest side wall line of the channel hole in the plate (hereinafter referred to as the "longest side wall line inclination angle α") is 5° or more and 75° or less,
The direction in which the channel axis direction is projected onto the sliding surface is called the sliding surface channel axis direction, and the direction in which the slide plate slides when the sliding gate is closed is called the sliding closing direction. The angle formed by the sliding surface flow path axis direction clockwise with respect to the closing direction when viewed in the sliding surface perpendicular downstream direction is called a flow path axis rotation angle θ (within a range of ±180 degrees). The axis line rotation angle θ differs between adjacent plates, and the θ of the plate on the most upstream side is θ ₁ , the θ of the plate one downstream of that is θ ₂ , and the θ of the plate one further downstream is θ Numbered in order from ₃ , and when the channel axis rotation angle difference Δθ _N = θ _N - θ _N+1 (N is an integer of 1 or more and up to the number of plates - 1), Δθ _N is all 10° or more and less than 170°, or both Δθ _N are greater than -170° and less than or equal to -10°.
However, the longest side wall line direction is the longest side wall of the channel hole in the cross section parallel to the sliding surface perpendicular downstream direction and including the graphic center of the upstream surface opening. It means the direction in which the sidewall line points. 2. The sliding gate according to claim 1, wherein the figure of said downstream surface apertures fits inside the figure of said upstream surface apertures when viewed in the downstream direction perpendicular to said sliding surface. 3. A sliding gate according to claim 1, wherein the number of plates forming the sliding gate is two or three and the number of slide plates is one.

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