JP2002160046A - Sliding nozzle apparatus and manufacturing method for steel under molten steel flow control using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erosion and tear at corners to plates in contact with a molten steel, and prevent cracking, peeling, etc., at corners due to sliding friction of the plates. SOLUTION: In a sliding nozzle apparatus comprising at least a movable plate with a nozzle bore to flow-through the molten steel and an immovable plate adjoining to the movable one with a nozzle bore to flow through the molten steel, the sliding nozzle apparatus and molten steel flow control method are provided with the gist of the employment of plate(s) with chamfer on at least one or more corners such as the corners formed between the top surface and/or the bottom surface of the movable plate and the bore inside wall of the movable plate, and/or the corners formed between the top surface and/or the bottom surface of the immovable plate and the bore inside wall of the immovable plate adjoining to the movable plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding nozzle device used in a process of injecting molten steel in a steelmaking process and a method of manufacturing steel using the device. More specifically, the present invention relates to a method for controlling a flow rate of molten steel using the sliding nozzle device. The present invention relates to a technique for preventing erosion of a flow rate adjustment plate by molten steel and a method for producing clean steel using the technique. The sliding nozzle device of the present invention can be suitably used as a flow control device for molten steel in continuous casting or the like.

[0002]

2. Description of the Related Art A so-called sliding nozzle device is used for controlling the flow rate of molten steel in continuous casting of steel or the like. The sliding nozzle device slides the movable plate having the molten steel flow hole formed therein, and adjusts the flow area of the molten steel by adjusting the area of the opening with the molten steel flow hole formed in the adjacent non-movable plate. I do. As a method for finely adjusting the flow rate of molten steel in such a sliding nozzle device, for example, JP-A-57-64461 and JP-A-61-99559 use a movable plate having a deformed molten steel flow hole. Thus, a method for controlling the flow rate of molten steel has been proposed. However, these prior arts
Although the precision of the flow rate control can be improved by deforming the shape of the molten steel flow holes, the problem of erosion and delamination occurring at the corners of the movable plate and the non-movable plate in contact with the flow molten steel when used for a long time. Had occurred. In addition, since the melting and peeling increase with the passage of time, the actual flow rate control ability is much lower than the theoretical value, the molten metal level in the mold is disturbed, and the damaged plate member is removed. Since it flows into the mold together with the molten steel, there is a problem that impurities are mixed in the steel material and the quality is deteriorated.

As a method for solving such a problem, for example, Japanese Patent Application Laid-Open No. 60-251168 discloses a method of improving the strength by using fine refractory particles at corners in order to prevent melting of a movable plate and a non-movable plate. Techniques have been proposed. However, although this technique can improve the strength of the corners, the corners over time,
The friction between the sliding plate members causes abrasion and peeling, and the molten steel flow causes erosion and peeling. Therefore, simply improving the strength cannot prevent erosion, abrasion and peeling of the corners. It is difficult, and furthermore, there has been a problem that the refractory which has been melted and peeled is mixed into steel as impurities.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is intended to prevent erosion and delamination of a corner of a plate in contact with molten steel, and to prevent the corner from being caused by sliding friction of the plate. By preventing cracks and peeling, etc., it is possible to reduce the occurrence of metal intrusion between the upper and lower plates by the damaged and peeled members, reduction in the smoothness of the sliding surface, and the incorporation of the molten and peeled members into steel. It is an object of the present invention to provide a technique capable of controlling the flow rate of molten steel by using a sliding nozzle device to which the technique is applied, while providing a technique capable of suppressing over a period.

[0005]

An apparatus according to the present invention which has solved the above-mentioned problems comprises a movable plate having at least a molten steel flow hole formed therein, and a molten steel flow hole formed adjacent to the movable plate. In the sliding nozzle device having the non-movable plate, the corner portion formed by the upper surface and / or the lower surface of the movable plate and the inner peripheral wall of the molten steel flow hole in the movable plate, and / or comes into contact with the movable plate. Upper surface of immovable plate, and / or
Alternatively, the sliding nozzle device has a gist of using a plate in which at least one or more corners formed by the lower surface and the inner peripheral wall of the molten steel flow hole in the immovable plate are chamfered.

At this time, it is recommended that the shape of the chamfered corner of the plate is formed by R and / or an obtuse angle, and that the surface direction and the thickness direction of the plate at the corner are each 1 mm or more. It is desirable to be chamfered.

[0007] The method for producing steel according to the present invention is directed to a sliding method comprising a movable plate having at least a molten steel flow hole, and a non-movable plate adjacent to the movable plate and having a molten steel flow hole. In a method for producing steel by controlling the flow rate of molten steel using a nozzle device, a corner portion formed by an upper surface and / or a lower surface of a movable plate and an inner peripheral wall of a molten steel flow hole in the movable plate; Alternatively, a sliding nozzle device having a plate in which at least one or more corners formed by the upper surface of the non-movable plate in contact with the movable plate and / or the lower surface and the inner peripheral wall of the molten steel flow hole in the non-movable plate are chamfered. This is a method for producing steel, which is based on the use of steel.

At this time, it is recommended that the shape of the chamfered corner portion of the plate is formed by R and / or obtuse angle to adjust the flow rate of the molten steel, and that the plate at the corner portion has a chamfered shape. It is desirable to adjust the flow rate of the molten steel by using a bevel whose surface direction and thickness direction are each chamfered to 1 mm or more.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When molten steel flows into a sliding surface between a movable plate and a non-movable plate, the smoothness of the plate is reduced, so that the plate corner portion is conventionally prevented from forming a gap between the plates. Had a right angle. However, due to the friction between the sliding plate members or the stress concentration of the molten steel flow at the right-angled corners, the portion is eroded and peeled over time, and molten steel flows between the plates from the eroded portion, and There has been a problem that the eroded portion is mixed into the steel material. The present inventors have conducted intensive studies on a method for solving the above problem, and as a result, have found that if the plate corner is chamfered and formed into a shape other than a right angle, melting and peeling of the corner can be prevented, leading to the present invention. . Hereinafter, the present invention will be described in detail with reference to FIG. FIG.
FIG. 3 is a schematic view showing an example of a molten steel flow rate adjusting plate used in a sliding nozzle device, and is not intended to limit the present invention thereto.

According to the present invention, which has prevented the erosion and peeling of the plate corner, a movable plate (2) having at least a molten steel flow hole (1), and a movable plate (2).
And a sliding nozzle device having a non-movable plate (4) in which a molten steel flow hole (3) is drilled, the upper surface and / or the lower surface of the movable plate and the molten steel flow hole (1) in the movable plate. ), And / or the upper and / or lower surfaces of the non-movable plate in contact with the movable plate (2) and the molten steel flow holes in the non-movable plate. A sliding nozzle device having a gist of using a plate in which at least one or more corners (7) and / or (8) formed with the inner peripheral wall of (3) are chamfered.

In the present invention, the "corner portion" is defined as an edge portion (5), (6), (7), formed by the surface of the plate and the inner peripheral wall of the molten steel flow hole formed in the plate.
In the present invention, at least the movable plate corners [(5), (6)] and / or the non-movable plate corners [(7),
(8)] is preferably chamfered at one or more places.

The movable plate (2) adjusts the opening area of the molten steel flow hole (3) of the adjacent non-movable plate (4),
A plate that slides for the purpose of controlling the flow rate of molten steel. The sliding method of the movable plate (2) can be appropriately selected according to the molten steel flow rate adjusting method, such as a linear reciprocating motion and a rotating motion, and is not particularly limited. The shape and diameter of the molten steel flow hole (1) formed in the movable plate (2) are not particularly limited, and can be appropriately selected depending on the purpose.

The non-movable plate (4) is a plate adjacent to the movable plate (2) and having a molten steel flow hole (3) formed therein. The installation position of the non-movable plate (4) may be above and / or below the movable plate (2), and may be appropriately determined according to the configuration of the apparatus. still,
The shape and diameter of the molten steel flow hole (3) formed in the immovable plate are not particularly limited, and can be appropriately selected according to the purpose. When the non-movable plate is installed only on one of the upper side and the lower side of the movable plate, the corner of the melt flow hole that is in contact with the surface opposite to the surface of the movable plate on which the non-movable plate is installed is chamfered. May be.

The corner portion to be chamfered is not particularly limited. If a severely eroded portion is chamfered, erosion of the portion can be prevented. It may be applied to the surface, and it is sufficient that at least one corner portion on the same circumference is chamfered. Further, from the viewpoint of preventing erosion and delamination of the corner portion and preventing the erosion portion from being mixed into the steel material, it is preferable to chamfer all corner portions in contact with the flowing molten steel. Also, the shape of the upper and lower adjacent plate corners may have different shapes, but the shape of the corners has the same shape on the same circumference. It is desirable from the viewpoint of preventing.

In the present invention, "chamfering" means changing the shape of the corner portion so that the plate corner portion has a shape other than a right angle. If chamfered, friction between the sliding plate members or stress concentration at the corners due to the molten steel flow can be suppressed, so that erosion and delamination can be prevented and refractory can be prevented from being mixed into the molten steel.

The shape of the chamfered corner portion is not particularly limited, but it is recommended that the corner portion is formed by R and / or an obtuse angle. For example, as shown in FIG. When the shape of the corner portion is R, it is desirable to form an arc having a radius equal to the sliding width of the plate that slides when the molten steel is injected. Further, as shown in FIG. 3, the shape may be a polygon having only an obtuse angle. In this case, the angle of the obtuse angle, the number of corners, and the length of one side (plane direction and thickness direction) are not particularly limited. . Alternatively, a combination of R and an obtuse angle illustrated in FIG. 4 may be used. Such a combination includes a shape as shown in FIG. 5 in which a straight line and R are combined, that is, a corner portion has a shape other than a right angle. As described above, it may be chamfered in a straight line with R, but from the viewpoint of reducing the stress due to the flowing molten steel, it is preferable that the length of one side is a width that constantly slides when the molten steel is injected.

Further, as shown in FIGS. 6 and 7, the surface direction and the thickness direction of the plate at the corners are each 1 mm.
It is desirable to be chamfered as described above from the viewpoint of reducing stress caused by molten steel. The upper limit is not particularly limited, but if the shape after chamfering has a right angle or an acute angle as shown in FIG. 8, the stress of the flowing molten steel is concentrated on the portion and the molten steel is easily melted. It is recommended that the length of one side be adjusted accordingly so that the shape after chamfering does not become a right angle or an acute angle.

The method of chamfering the corner is not particularly limited, and the corner may be chamfered by, for example, a hand grinder.

The material of the movable plate and the non-movable plate,
The shape and size are not particularly limited, and can be appropriately selected according to the intended use. Further, a plate whose strength is improved by a refractory or the like may be used.

If the flow rate of molten steel is adjusted by using the sliding nozzle device using the chamfered plate of the present invention, wear and separation due to sliding friction between the plates can be prevented, and erosion due to the flow of molten steel can be prevented. Peeling can be prevented. As a result, the base metal is drawn between the upper and lower plates from the erosion-peeling portion, and the smoothness of the sliding surface where the two plates come into contact is lost. it can. In addition, the refractory mixed into the molten steel can be prevented, and the refractory mixed into the steel material can be significantly reduced.Therefore, if the flow rate of the molten steel is adjusted by the sliding nozzle device using the plate of the present invention, the cleanliness can be improved. High steel can be manufactured.

The operating conditions of the sliding nozzle device, the flow rate of molten steel, and the like are not particularly limited, and can be appropriately set according to the purpose.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are not intended to limit the present invention, and all changes and implementations without departing from the spirit of the present invention will be described. Included in the scope.

[0023]

EXAMPLE A test was conducted on the corners of the respective plates used in the sliding nozzle device of a 90-ton molten steel pot and the sliding nozzle device of a 14-ton tundish after the molten steel was injected into the corner portions and the refractories were mixed into the molten steel. The erosion at each plate corner was evaluated according to the following criteria. Regarding the refractory mixture, 50 g of a steel material was dissolved in a mixed solution of sulfuric acid and nitric acid, suction-filtered with a 10 μm filter, and the composition of the remaining nonmetallic inclusions was determined by EPMA. The number was measured. Corner erosion evaluation standard (Evaluated based on the longer erosion length in either the thickness direction or the surface direction of the plate corner) 0: No erosion 1: More than 0 to 0.5 mm 2: More than 0.5 to 1 0.0mm 3: More than 1.0 to 1.5mm 4: More than 1.5 to 2.0mm 5: More than 2.0 to 2.5mm 6: More than 2.5

Example 1 Using a sliding nozzle device of a 90t molten steel pot as shown in FIG. 9, the molten state of the corner of the molten steel flow hole of the movable plate and the corner of the molten steel flow hole of the non-movable plate, It was tested for refractory contamination. The material of the plate in each test example was a refractory of ZrO ₂ quality, and the hole diameter used was a perfect circle (hole diameter: 60 mm). The sliding method of the sliding nozzle device was a linear reciprocating motion, and the sliding nozzle device was operated with a sliding width of ± 5 mm. The shape of the plate corner in each test example is as described in Table 1. The flow rate of the molten steel (1540 ° C.) used in the test was 230
L / min and circulated for 5 hours. The corners of the movable plate and the corners of the non-movable plate of the comparative example are both right angles, and are conventional plates in which the corners are not chamfered. Table 1 shows the results.

[0025]

[Table 1]

As is evident from Table 1, none of the test examples of the present invention in which the corners of the plate were chamfered exhibited erosion or peeling, and almost no refractory was mixed into the molten steel. On the other hand, the plate corners of the comparative example were eroded and peeled (see FIG. 11), the metal was drawn between the plates, and refractory was mixed into the molten steel.

Example 2 A corner erosion state was tested in the same manner as in Example 1 except that a tundish sliding nozzle as shown in FIG. 10 was used. The same material as in Example 1 was used as the material of the plate in each test example except that the hole diameter was 50 mm. The sliding method of the sliding nozzle device was a linear reciprocating motion, and the device was operated with a sliding width of ± 2 mm. The shape of the plate corner in each test example is as described in Table 1. The flow rate of the molten steel (1510 ° C.) used in the test was 142 L / min, and the steel was allowed to flow for 14 hours. Table 2 shows the results. Here, the corners of the movable plate and the corners of the non-movable plate of the comparative example are both right-angled. The non-movable plates installed above and below the movable plate are the same as the upper and lower portions.

[0028]

[Table 2]

As is clear from Table 2, in all of the test examples of the present invention in which the corners of the plate were chamfered, no erosion and peeling occurred, and almost no refractory was mixed into the molten steel. On the other hand, in the plate corner of the comparative example, erosion and peeling occurred (see FIG. 12), metal was pulled in between the plates, and refractory was mixed in the molten steel. In this case, the erosion of the plate corner was remarkably improved, and the quality of the steel was improved.

[0030]

By adopting a plate having a chamfered corner in the sliding nozzle device, wear and separation due to sliding friction between the plates can be prevented, and erosion and separation due to molten steel flow can be prevented. can do. As a result, conventionally, the metal is drawn between the upper and lower plates from the erosion-exfoliated portion, the smoothness of the sliding surface where both plates are in contact is lost, and furthermore, the smelting of the metal is promoted and the erosion-exfoliation is prevented from expanding. it can. This can prevent refractories from being mixed into the molten steel and eliminate refractories mixed into the steel material. This significantly improves the cleanliness of the steel.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a molten steel flow rate adjusting plate of the present invention used in a sliding nozzle device.

FIG. 2 is a perspective view showing a shape in which a corner portion is chamfered according to the present invention, and is an example of a shape having an R;

FIG. 3 is a perspective view showing a shape in which a corner portion is chamfered, and is an example of a shape having a polygon.

FIG. 4 is a perspective view showing a shape in which a corner portion of the present invention is chamfered, and is an example of a shape having an obtuse angle with R;

FIG. 5 is a perspective view showing a shape in which a corner portion is chamfered, and is an example of a shape having an obtuse angle with R.

FIG. 6 is a cross-sectional view showing an example of a shape in which a corner portion is chamfered according to the present invention.

FIG. 7 is a cross-sectional view illustrating an example of a shape in which a corner portion is chamfered according to the present invention.

FIG. 8 is a sectional view showing an example of a shape in which a corner portion is chamfered.

FIG. 9 is a schematic view showing a sliding nozzle of a ladle used in an example.

FIG. 10 is a schematic view showing a tundish sliding nozzle used in an example.

FIG. 11 is a diagram showing a state of a plate of a comparative example in which erosion has occurred.

FIG. 12 is a diagram showing a state of a plate of a comparative example in which erosion has occurred.

[Explanation of symbols]

 1,3 molten steel flow hole 2 movable plate 4 non-movable plate 5,6,7,8 corner

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takanori Konan 2 Nadahama-Higashicho, Nada-ku, Kobe Kobe Steel Works Kobe Works F-term (reference) 4E014 MA01 MA05 MA06 MA11

Claims (6)

[Claims] 1. A sliding nozzle device having at least a movable plate having a molten steel flow hole formed therein and a non-movable plate adjacent to the movable plate and having a molten steel flow hole formed therein, the upper surface of the movable plate being provided with: and/
Or a corner formed by the lower surface and the inner peripheral wall of the molten steel flow hole in the movable plate, and / or the upper surface of the non-movable plate in contact with the movable plate, and / or the lower surface and the molten steel flow hole in the non-movable plate. A sliding nozzle device characterized by using a plate in which at least one or more corners formed by an inner peripheral wall are chamfered. 2. The sliding nozzle device according to claim 1, wherein the shape of the chamfered corner portion of the plate is formed by R and / or an obtuse angle. 3. The sliding nozzle device according to claim 1, wherein a surface direction and a thickness direction of the plate at the corner portion are each chamfered to 1 mm or more. 4. A flow rate of molten steel is determined by using a sliding nozzle device having at least a movable plate having a molten steel flow hole formed therein and a non-movable plate adjacent to the movable plate and having a molten steel flow hole formed therein. In the adjusting method, a corner portion formed by an upper surface and / or a lower surface of the movable plate and an inner peripheral wall of a molten steel flow hole in the movable plate, and / or an upper surface of a non-movable plate in contact with the movable plate, and / or Or a steel characterized in that the flow rate of molten steel is adjusted by using a sliding nozzle device having a plate formed by chamfering at least one corner at a corner formed by a lower surface and an inner peripheral wall of a molten steel flow hole in the immovable plate. Manufacturing method. 5. The method for producing steel according to claim 4, wherein the shape of the chamfered corner portion of the plate is formed by R and / or an obtuse angle. 6. The method for producing steel according to claim 4, wherein a surface direction and a thickness direction of the plate at the corner portion are each chamfered to 1 mm or more.