JPWO2020036179A1 - Ladle for molten metal - Google Patents

Abstract

A molten metal pan having a pan body and a fireproof layer disposed inside the pan body, and having tranny shafts on both sides of the pan body, the pan body. The horizontal cross section including the tranion axis has a center on the axis connecting the tranion axes, has a radius of curvature of R1, and includes a first arc including a portion orthogonal to the tranion axis and a central axis orthogonal to the axis. A second arc having a center on the top, having a radius of curvature of R2, and including a portion orthogonal to the central axis, and a curved portion having a minimum radius of curvature of R3MIN connecting the first arc and the second arc. , The radius of curvature R1 of the first arc, the radius of curvature R2 of the second arc, and the minimum radius of curvature R3MIN of the curved portion are the following equations (1) to (3). To be satisfied. Equation (1): 0.401 × R1 <R3MIN <R1 (2) Equation: 0.401 × R2 <R3MIN <R2 (3) Equation: R1 ≦ R2

Description

The present invention relates to, for example, a ladle for molten metal that holds molten metal such as hot metal or molten steel in a steel mill or the like.
The present application claims priority based on Japanese Patent Application No. 2018-152619 filed in Japan on August 14, 2018, the contents of which are incorporated herein by reference.

For example, in ironworks and the like, hot metal and molten steel from converters and torpedo cars are held in a ladle (a ladle for molten metal) and transported.
This ladle for molten metal has a structure provided with an iron ladle body and a refractory layer arranged inside the ladle body in order to hold the high-temperature molten metal. Further, trunnion shafts are provided on both sides in the width direction of the ladle body, and the trunnion shaft can be lifted by a crane or the like and tilted around the trunnion shaft.
Conventionally, as the above-mentioned ladle for molten metal, as shown in Patent Document 1, for example, one in which the horizontal cross-sectional shape of the ladle body is circular or elliptical has been proposed.

Since the above-mentioned ladle for molten metal holds high-temperature molten metal, the refractory layer arranged inside the ladle body is thermally deteriorated and cracks and the like occur. Therefore, it is necessary to regularly repair the refractory layer according to a certain number of uses.
Here, by increasing the pot volume of the molten metal ladle, the amount of molten metal handled up to the repair work of the refractory layer can be increased, and the manufacturing cost can be reduced.

In order to increase the pot volume of the molten metal ladle, it is conceivable to increase the outer shape of the ladle body. However, if the outer shape of the molten metal ladle is enlarged, it is not realistic because the entire equipment needs to be significantly modified in order to make other equipment such as a crane correspond to the outer shape of the molten metal ladle. Absent.
Therefore, for example, Patent Document 2 proposes a ladle for molten metal in which the volume of the pan is expanded without significantly changing the outer shape of the ladle for molten metal. In the molten metal ladle described in Patent Document 2, the pot volume is expanded by approximating the horizontal cross-sectional shape of the ladle body to a rectangular shape. Further, by forming the horizontal cross section with an arc, stress concentration at the corners is suppressed.

Japanese Patent Application Laid-Open No. 2000-256728 Japanese Patent Application Laid-Open No. 2016-059940

By the way, recently, in order to further reduce the manufacturing cost, it is required to further reduce the number of repairs of the refractory layer in the ladle for molten metal.
Here, in the ladle for molten metal described in Patent Document 2, the horizontal cross section is formed of an arc to suppress the stress concentration at the corners, but the stress on the refractory layer can be sufficiently reduced. Therefore, there was a risk that the number of repairs of the refractory layer would increase. Further, recently, it is required to extend the service life of the ladle for molten metal, and it is necessary to reduce the thermal stress on the ladle body to suppress the deformation of the ladle body.

The present invention has been made in view of the above-mentioned situation, and it is possible to increase the pot volume of the molten metal ladle and reduce the number of repairs by suppressing the thermal stress acting on the molten metal ladle. It is an object of the present invention to provide a ladle for molten metal which can be used.

In order to solve the above problems, the molten metal pan according to the present invention has a pan body and a fireproof layer disposed inside the pan body, and both sides of the pan body. A molten metal pan provided with a tranny shaft, wherein the horizontal cross section of the pan body including the tranny shaft has a center on an axis connecting the tranny shafts, the radius of curvature is R1, and the tranny. A first arc including a portion orthogonal to the axis, a second arc having a center on a central axis orthogonal to the axis, a radius of curvature R2, and including a portion orthogonal to the central axis, and the first arc. It has a non-circular shape including a curved portion having a minimum radius of curvature of R3 _MIN connecting the second arc and the second arc, and has a radius of curvature R1 of the first arc, a radius of curvature R2 of the second arc, and the like. The minimum radius of curvature R3 _{MIN of the} curved portion satisfies the following equations (1) to (3).
Equation (1): 0.401 × R1 <R3 _MIN <R1
Equation (2): 0.401 × R2 <R3 _MIN <R2
Equation (3): R1 ≤ R2

According to the molten metal pan of this configuration, the horizontal cross section of the pan body including the tranion axis has a center on the axis connecting the tranion axes, the radius of curvature is R1, and is orthogonal to the tranion axis. A first arc including a portion to be formed, a second arc having a center on a central axis orthogonal to the axis, a radius of curvature of R2, and a portion orthogonal to the central axis, the first arc, and the first arc. connecting the 2 arc, and the curved portion is the minimum radius of curvature _{R3 MIN,} which is a non-circular shape with a minimum radius of curvature _{R3 MIN} of the curved _portion, and _{R3 MIN <R1, R3 MIN <} R2 Therefore, the first arc and the second arc having a large radius of curvature are connected by a curved portion having a small radius of curvature, the horizontal cross section approximates a rectangular shape, and the horizontal cross section forms a circular shape. It is possible to expand the pot volume with respect to the pot body.

Further, since the minimum radius of curvature R3 _MIN of the curved portion satisfies 0.401 × R1 <R3 _MIN and 0.401 × R2 <R3 _MIN , the minimum radius of curvature R3 _{MIN of the} curved portion is the first. It does not become too small with respect to the radius of curvature of the arc and the second arc, and stress concentration can be suppressed at the connection between the first arc and the curved part and the second arc and the curved part, and the deformation of the pot body and the fireproof layer Deterioration can be suppressed. This makes it possible to reduce the number of refractory repairs for the molten metal ladle.
Therefore, the volume of the molten metal ladle can be increased, and the thermal stress acting on the molten metal ladle can be suppressed to reduce the number of repairs.

Here, in the ladle for molten metal of the present invention, the refractory layer is arranged inside the first refractory layer arranged on the side of the ladle body and the first refractory layer. A second refractory layer is provided, the first refractory layer may be made of refractory bricks, and the second refractory layer may be made of an amorphous refractory.
In this case, even if stress acts on the refractory layer to cause cracks, it is possible to prevent the cracks from propagating to the first refractory material made of refractory bricks, and the cracks are arranged further inside the first refractory layer. The second refractory layer may be repaired. Since the second refractory layer is composed of an amorphous refractory, it can be repaired relatively easily. Further, the repair cost can be further reduced by suppressing the thermal stress acting on the second refractory layer.

As described above, according to the present invention, it is possible to increase the pot volume of the molten metal ladle and to suppress the thermal stress acting on the molten metal ladle to reduce the number of repairs. A metal ladle can be provided.

It is a side explanatory view which shows an example of the ladle for molten metal which is embodiment of this invention. It is a top view which shows an example of the ladle for molten metal which is an embodiment of this invention. It is explanatory drawing which shows the horizontal cross-sectional shape of the ladle body of the ladle for molten metal which is an embodiment of this invention. It is explanatory drawing which shows the structure of the refractory layer in the ladle for molten metal which is an embodiment of this invention. It is a graph which shows the result of Example 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments.

The ladle 1 for molten metal according to the present embodiment includes a ladle body 10 and a refractory layer 20.
The trunnion shafts 18 and 18 are provided on both sides of the ladle body 10 in the width direction, and the trunnion shafts 18 and 18 can be used to transport the ladle body 10 by a crane or the like and further tilt around the trunnion shafts 18 and 18. It is configured.

Further, in the present embodiment, the ladle body 10 has a non-circular shape as shown in FIG. 3 in a horizontal cross section including the trunnion shaft 18.
Specifically, the first arc 11 having a center on the axis S1 connecting the tranny axes 18 and 18 and having a radius of curvature R1 including a portion orthogonal to the tranny axis 18, and the central axis S2 orthogonal to the axis S1. A curve having a center on the top, a radius of curvature of R2, and a minimum radius of curvature of R3 _MIN connecting a second arc 12 including a portion orthogonal to the central axis S2, a first arc 11 and a second arc 12. It has a shape including a portion 13.
In this embodiment, the radii of curvature R1, R2, R3 _MIN of the horizontal cross section of the ladle body 10 are measured on the inner wall surface of the ladle body 10.

Since the first arc 11 has a center on the axis S1 connecting the trunnion axes 18 and 18, the surface on which the trunnion axes 18 and 18 are arranged becomes the above-mentioned first arc 11.
Further, since the second arc 12 has a center on the central axis S2 orthogonal to the axis lines S1 connecting the tranny axes 18 and 18, it is formed in a direction orthogonal to the first arc 11. Become.
The curved portion 13 is arranged at a corner where the first arc 11 and the second arc 12 intersect.

Here, the radius of curvature R1 of the first arc 11, the radius of curvature R2 of the second arc 12, and the minimum radius of curvature R3 _{MIN of} the curved portion 13 satisfy the following equations (1) to (3).
Equation (1): 0.401 × R1 <R3 _MIN <R1
Equation (2): 0.401 × R2 <R3 _MIN <R2
Equation (3): R1 ≤ R2

As described above, the minimum radius of curvature R3 _MIN of the curved portion 13 is set to R3 _MIN <R1 and R3 _MIN <R2 with respect to the radius of curvature R1 of the first arc 11 and the radius of curvature R2 of the second arc 12. Therefore, the intersection (corner portion) of the first arc 11 and the second arc 12 protrudes outward to form a shape similar to a rectangular shape, and the outer shape is larger than that of the pot body having a circular horizontal cross section. It is possible to expand the volume without changing.
In order to secure the volume, it is preferable that the upper limit of the minimum radius of curvature R3 _MIN of the curved portion 13 is 0.9 × R1 and 0.9 × R2.

Further, the minimum radius of curvature R3 _{MIN of} the curved portion 13 is 0.401 × R1 <R3 _MIN and 0.401 × R2 with respect to the radius of curvature R1 of the first arc 11 and the radius of curvature R2 of the second arc 12. <R3 _MIN . That is, the lower limit of the minimum radius of curvature R3 _MIN of the curved portion 13 is defined.
By defining the lower limit of the minimum radius of curvature R3 _MIN of the curved portion 13 in this way, stress concentration at the connecting portion between the first arc 11 and the curved portion 13 and the second arc 12 and the curved portion 13 can be suppressed. Is possible. As a result, it is possible to suppress deformation of the ladle body 10 and deterioration of the refractory layer 20.

In order to further suppress stress concentration at the connection between the first arc 11 and the curved portion 13 and the second arc 12 and the curved portion 13, the lower limit of the minimum radius of curvature R3 _MIN of the curved portion 13 is set to 0.41 ×. R1 and 0.41 × R2 are preferable, 0.42 × R1 and 0.42 × R2 are more preferable, and 0.45 × R1 and 0.45 × R2 are more preferable.

Further, in the present embodiment, as shown in FIG. 4, the refractory layer 20 is arranged inside the first refractory layer 21 arranged on the side of the ladle body 10 and the first refractory layer 21. It is provided with a second refractory layer 22 provided.
Here, in the present embodiment, the first refractory layer 21 is formed by stacking refractory bricks. Further, the second refractory layer 22 is formed of an amorphous refractory material. The second refractory layer 22 may be formed by refractory bricks in the region where the molten metal surface is located in order to suppress melting damage.
The ratio t2 / t1 of the thickness t1 of the first refractory layer 21 to the thickness t2 of the second refractory layer 22 is preferably 1 or more, and more preferably 2 or more.

Then, in the molten metal ladle 1 of the present embodiment, the hot metal or molten steel from the converter or the torpedo car is received, the hook of the overhead crane is locked to the trunnion shafts 18, 18 and conveyed, and the trunnion shaft 18, By tilting around 18, the hot metal or molten steel is transferred to the container in the next process.
In this way, the molten metal ladle 1 is repeatedly subjected to severe thermal stress by injecting and discharging hot hot metal or molten steel.
Then, when the refractory layer 20 arranged inside the ladle body 10 is cracked or the like, the refractory layer 20 is repaired and used again.

According to the molten metal pan 1 of the present embodiment having the above configuration, the horizontal cross section of the pan body 10 including the tranny shaft 18 is centered on the axis S1 connecting the tranny shafts 18 and 18. It has a first arc 11 including a portion orthogonal to the tranny axis 18 and a radius of curvature R1, has a center on a central axis S2 orthogonal to the axis S1, has a radius of curvature R2, and is orthogonal to the central axis S2. It has a non-circular shape including a second arc 12 including a portion to be formed, and a curved portion 13 having a minimum radius of curvature of R3 _MIN connecting the first arc 11 and the second arc 12. Since the minimum radius of curvature R3 _{MIN of} is set to R3 _MIN <R1 and R3 _MIN <R2, the horizontal cross section has a shape similar to a rectangular shape, and the pot volume is relative to the pot body having a circular horizontal cross section. Can be expanded.

Further, since the minimum radius of curvature R3 _{MIN of} the curved portion 13 is 0.401 × R1 <R3 _MIN and 0.401 × R2 <R3 _MIN , the minimum radius of curvature R3 _{MIN of} the curved portion 13 does not become too small. , The stress concentration at the connection portion between the first arc 11 and the curved portion 13 and the second arc 12 and the curved portion 13 can be suppressed, and the deformation of the pan body 10 and the deterioration of the refractory layer 20 can be suppressed. This makes it possible to reduce the number of repairs of the molten metal ladle 1.

Further, in the present embodiment, the refractory layer 20 includes a first refractory layer 21 arranged on the side of the pan body 10 and a second refractory layer arranged inside the first refractory layer 21. A layer 22 is provided, and when the first refractory layer 21 is made of refractory bricks and the second refractory layer 22 is made of amorphous refractory, it is arranged on the side of the pan body 10. It is possible to suppress the concentration of stress on the first refractory layer 21 and further extend the life of the first refractory layer 21. Further, even if stress acts on the refractory layer 20 to cause cracks, it is possible to prevent the cracks from propagating to the first refractory layer 21 made of refractory bricks, and further inside the first refractory layer 21. The arranged second refractory layer 22 may be repaired. Since the second refractory layer is composed of an amorphous refractory, it can be repaired relatively easily, and the repair cost can be further reduced.

Although the ladle for molten metal, which is an embodiment of the present invention, has been specifically described above, the present invention is not limited to this, and can be appropriately changed without departing from the technical idea of the invention. ..
For example, in the present embodiment, the molten metal ladle having the trunnion shaft having the structure shown in FIG. 1 has been described as an example, but the present invention is not limited to this, and the ladle has a trunnion shaft having another structure. There may be.

Further, in the present embodiment, the hot metal and the molten steel have been described as being held and transferred, but the present invention is not limited to this, and other molten metals may be handled.
Further, in the present embodiment, the refractory layer has been described as having a first refractory layer and a second refractory layer, but the present invention is not limited to this, and the refractory layer has one refractory layer. It may be present, or it may have three or more refractory layers.

The results of experiments carried out in order to confirm the effects of the present invention will be described below.

<Example 1>
As an example of the present invention, the ladle for molten metal described in the above-described embodiment was prepared. The radius of curvature R1 of the first arc was 4170 mm, the radius of curvature R2 of the second arc was 4170 mm, and the minimum radius of curvature R3 _MIN of the curved portion was 1700 mm. That is, 0.401 × R1 <R3 _MIN <R1, 0.401 × R2 <R3 _MIN <R2, R1 ≦ R2 was satisfied.
As a comparative example, the radius of curvature R1 of the first arc was 4170 mm, the radius of curvature R2 of the second arc was 4170 mm, and the minimum radius of curvature R3 _MIN of the curved portion was 1150 mm. That is, it is assumed that the relationship is R3 _MIN <0.401 × R1 and R3 _MIN <0.401 × R2.

The minimum value of the residual thickness of the refractory layer after use was measured using the molten metal ladle of the present invention example and the comparative example. In FIG. 5, when the initial thickness of the examples of the present invention and the comparative example is set to "1", the relationship with the minimum value of the residual thickness of the refractory layer, and the number of times of use for the refractory life of the present invention is set to 1. In the comparative example, the number of times of use for the life of the refractory is shown as a relative value.
As shown in FIG. 5, the molten metal ladle of the present invention has a thicker residual thickness of the refractory layer after use than the molten metal ladle of the comparative example, and the service life can be extended. Was confirmed.
Further, in the molten metal ladle of the example of the present invention, the pot volume could be expanded as compared with the molten metal ladle having a circular horizontal cross section.

<Example 2>
Test No. As A to H, in a horizontal cross section including the tranion axis 18, a first arc having a center on an axis connecting the tranion axis, a radius of curvature of R1, and a portion orthogonal to the tranion axis, and orthogonal to the axis. A second arc having a center on the central axis, having a radius of curvature of R2, and including a portion orthogonal to the central axis, and connecting the first arc and the second arc with a minimum radius of curvature of R3 _MIN . A hot pot for molten metal having a certain curved portion and a shape including the curved portion was prepared. The relationship between R1, R2, and R3 _MIN is shown in Table 1. Table 1 shows the ratio t2 / t1 of the thickness t1 of the first refractory layer (refractory brick) and the thickness t2 of the second refractory layer (amorphous refractory).

The molten steel was transferred using the above-mentioned ladle for molten metal. At this time, the effective volume of the ladle, the number of times of use, the minimum value of the residual thickness of the refractory layer, and the presence or absence of cracks in the refractory layer at the curved portion were evaluated. The various evaluations were relative evaluations based on test A (= 1). The evaluation results are shown in Table 1.

Test No. with R3 _MIN = 0.3 × R1 and R3 _MIN = 0.3 × R2. Test No. G and R3 _MIN = 0.25 × R1, R3 _MIN = 0.25 × R2. In H, a crack was generated in the refractory layer at the curved portion.

Test No. that satisfies 0.401 × R1 <R3 _MIN <R1, 0.401 × R2 <R3 _MIN <R2. In B to F, the test No. 1 having a circular horizontal cross section. The effective volume was larger than that of A. In addition, the occurrence of cracks in the refractory layer at the curved portion could be suppressed.
No. E and No. 1 with R3 _MIN = 0.401 × R1 and R3 _MIN = 0.401 × R2. Comparing with F, No. 1 in which the ratio t2 / t1 of the thickness t1 of the first refractory layer (refractory brick) and the thickness t2 of the second refractory layer (amorphous refractory) was 1. E is No. 1 in which t2 / t1 is 0.5. Compared to F, the refractory layer was used more frequently until the residual thickness of the refractory layer reached 40 mm, and the life of the refractory layer could be extended.

According to the present invention, it is possible to increase the pot volume of the molten metal ladle, suppress the thermal stress acting on the molten metal ladle, and reduce the number of repairs. Can be provided.

1 Ladle for molten metal 10 Ladle body 11 1st arc 12 2nd arc 13 Curved part 18 Trunnion shaft 20 Refractory layer 21 1st refractory layer 22 2nd refractory layer

Claims (2)

A ladle for molten metal having a ladle body and a refractory layer disposed inside the ladle body, and having trunnion shafts on both sides of the ladle body.
The horizontal cross section of the ladle body including the trunnion axis is
A first arc having a center on the axis connecting the trunnion axes, having a radius of curvature of R1, and including a portion orthogonal to the trunnion axes.
A second arc having a center on a central axis orthogonal to the axis, having a radius of curvature of R2, and including a portion orthogonal to the central axis.
A curved portion having a minimum radius of curvature of R3 _MIN connecting the first arc and the second arc,
It is said to have a non-circular shape with
For molten metal, the radius of curvature R1 of the first arc, the radius of curvature R2 of the second arc, and the minimum radius of curvature R3 _{MIN of the} curved portion satisfy the following equations (1) to (3). Tori pot.
Equation (1): 0.401 × R1 <R3 _MIN <R1
Equation (2): 0.401 × R2 <R3 _MIN <R2
Equation (3): R1 ≤ R2 The refractory layer includes a first refractory layer arranged on the side of the ladle body and a second refractory layer arranged inside the first refractory layer.
The ladle for molten metal according to claim 1, wherein the first refractory layer is made of refractory bricks, and the second refractory layer is made of an amorphous refractory material.

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