TWI716065B - Ladle for molten metal - Google Patents

Abstract

The present invention provides a ladle for molten metal including a ladle body with trunnion shafts, and a refractory layer provided on an inside of the ladle body. A horizontal cross section of the ladle body at the trunnion shafts has a non-circular shape and includes a first circular arc having a center point on an axis line connecting the trunnion shafts, a second circular arc having a center point on a center axis perpendicular to the axis line, and a curving portion connecting the first circular arc and the second circular arc. A radius of curvature R1 of the first circular arc, a radius of curvature R2 of the second circular arc, and a minimum radius of curvature R3MIN satisfy following equations (1) to (3). 0.401×R1>R3MIN>R1 Equation (1) 0.401×R2>R3MIN>R2 Equation (2) R1≦R2 Equation (3)

Description

Pouring bucket for molten metal

Invention field The present invention relates to a molten metal ladle for holding molten metal such as molten iron or molten steel, for example, in an iron mill. This application claims priority based on Japanese Patent Application No. 2018-152619 filed in Japan on August 14, 2018, and its content is cited here.

Background of the invention For example, in ironworks, etc., molten iron or molten steel from a converter or a torpedo car (torpedo car) is held in a ladle (a ladle for molten metal) and transported. In this molten metal ladle, since it is necessary to maintain high-temperature molten metal, it has a structure including a ladle body made of iron and a refractory layer arranged inside the ladle body. In addition, trunnions are provided on both sides in the width direction of the ladle body, and the trunnions can be lifted by a crane or the like, and the trunnions can be tilted around the trunnions. Conventionally, as the above-mentioned molten metal ladle, for example, as shown in Patent Document 1, there has been proposed that the horizontal cross-sectional shape of the ladle body is a circular shape or an elliptical shape.

Since the ladle for molten metal described above is a molten metal that maintains a high temperature, the refractory layer arranged on the inner side of the ladle body is thermally degraded, causing cracks and the like. Therefore, the refractory layer must be regularly repaired according to a certain number of uses. Here, by increasing the volume of the molten metal ladle, the amount of molten metal processed before the repairing operation of the refractory layer can be increased, and the manufacturing cost can be reduced.

In order to increase the volume of the ladle for molten metal, it is conceivable to increase the shape of the ladle body. However, in order to increase the shape of the molten metal ladle, in order to make other equipment such as cranes correspond to the shape of the molten metal ladle, it is necessary to greatly modify the entire equipment, which is not practical. Therefore, for example, in Patent Document 2, there has been proposed a ladle for molten metal in which the volume of the ladle is enlarged without greatly changing the shape of the ladle for molten metal. In the molten metal ladle described in Patent Document 2, the volume of the ladle is expanded by making the horizontal cross-sectional shape of the ladle body approximate to a rectangular shape. In addition, by forming a horizontal cross section with circular arcs, stress concentration in the corners is suppressed. Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2000-256728 Patent Document 2: Japanese Patent Laid-Open No. 2016-059940

Summary of the invention Problems to be solved by the invention In addition, recently, in order to further reduce the manufacturing cost, there is a demand for further reduction in the number of repairs of the refractory layer in the molten metal ladle. Here, in the molten metal ladle described in Patent Document 2, although the horizontal section is formed by circular arcs to suppress the stress concentration at the corners, the stress on the refractory layer is not sufficiently reduced, and there is a refractory layer. The number of repairs may increase. In addition, 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 was made in view of the foregoing situation, and its object is to provide a molten metal pouring tank that can expand the volume of the molten metal pouring bucket, and can suppress the thermal stress acting on the molten metal pouring bucket and reduce the number of repairs. barrel. Means to solve the problem

In order to solve the above-mentioned problems, the molten metal ladle of the present invention has a ladle body and a refractory layer arranged inside the ladle body, and has trunnions on both sides of the ladle body. The pouring bucket is characterized in that: the horizontal section of the pouring bucket body including the trunnion is made into a non-circular shape, and is provided with: a first arc having a center on the axis connecting the trunnion, and a radius of curvature of R1 includes a portion orthogonal to the aforementioned trunnion; a second arc has a center on a central axis orthogonal to the aforementioned axis, and has a radius of curvature of R2, and includes a portion orthogonal to the aforementioned central axis; and a curve Section, connecting the first arc and the second arc, and the minimum radius of curvature is R3 _MIN , and the radius of curvature of the first arc is R1, the radius of curvature of the second arc R2, and the minimum of the curve The radius of curvature R3 _MIN satisfies the following equations (1) to (3). (1) Formula: 0.401×R1＜R3 _MIN ＜R1 (2) Formula: 0.401×R2＜R3 _MIN ＜R2 (3) Formula: R1≦R2

According to the molten metal ladle of this structure, the horizontal section of the ladle body including the trunnion is made into a non-circular shape, and the ladle has a first arc having a center on the axis connecting the trunnion, and The radius of curvature is R1 and includes the part orthogonal to the aforementioned trunnion; the second arc has a center on the central axis orthogonal to the aforementioned axis, and the radius of curvature is R2, and includes the part orthogonal to the aforementioned central axis ; And the curved part, connecting the first arc and the second arc, and the minimum radius of curvature is R3 _MIN , and the minimum radius of curvature R3 _MIN of the curved part is set to R3 _MIN <R1, R3 _MIN <R2, Therefore, the first arc and the second arc with a large radius of curvature are connected by a curved portion with a small radius of curvature, so that the horizontal cross section is approximately rectangular, and the bucket body can be formed into a circular shape with respect to the horizontal cross section. , Expand the barrel volume.

In addition, the minimum radius of curvature R3 _{MIN of the} curved portion satisfies 0.401×R1<R3 _MIN and 0.401×R2<R3 _MIN , so the minimum radius of curvature R3 _MIN of the curved portion relative to the first arc and the second arc The radius of curvature does not become too small, and the stress concentration in the connecting portion between the first arc and the curve portion, and the second arc and the curve portion can be suppressed, and the deformation of the ladle body or the deterioration of the refractory layer can be suppressed. Thereby, the number of refractory repairs of the molten metal pouring bucket can be reduced. Therefore, the volume of the ladle for molten metal can be enlarged, the thermal stress acting on the ladle for molten metal can be suppressed, and the number of repairs can be reduced.

Here, in the molten metal ladle of the present invention, the refractory layer includes a first refractory layer arranged on the side of the ladle body, and a second refractory layer arranged on the inner side of the first refractory layer. For the refractory layer, the first refractory layer may be made of refractory bricks, and the second refractory layer may be made of unshaped refractory. At this time, even if the stress acts on the refractory layer to cause cracks, the propagation of the cracks to the first refractory made of refractory bricks can be suppressed, and only the second refractory disposed on the inner side of the first refractory layer can be repaired. The layer can be. Since the second refractory layer is composed of unshaped refractory, it can be repaired relatively easily. In addition, by suppressing the thermal stress acting on the second refractory layer, the repair cost can be further reduced. Invention effect

As described above, according to the present invention, it is possible to provide a molten metal ladle which can expand the volume of the molten metal ladle, and can suppress the thermal stress acting on the molten metal ladle to reduce the number of repairs.

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

The molten metal ladle 1 of this embodiment includes a ladle body 10 and a refractory layer 20. The ladle body 10 is provided with trunnions 18 and 18 on both sides in the width direction, and is configured to be transported by a crane or the like using the trunnions 18 and 18, and can also tilt around the trunnions 18 and 18 as the center.

Furthermore, in this embodiment, as shown in FIG. 3, the horizontal cross section of the ladle body 10 including the trunnion 18 is made into a non-circular shape. Specifically, its shape is made to have: the first arc 11 has a center on the axis S1 connecting the trunnions 18, 18, and the radius of curvature is R1, and includes a portion orthogonal to the trunnion 18; The arc 12 has a center on the central axis S2 orthogonal to the axis S1, and has a radius of curvature of R2, and includes a portion orthogonal to the central axis S2; and a curved portion 13, connecting the first arc 11 and the second circle Arc 12, and the minimum radius of curvature is R3 _MIN . In addition, in the present embodiment, the radii of curvature R1, R2, R3 _MIN of the horizontal section of the ladle body 10 are set to the radii of curvature 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 trunnions 18 and 18, the surface on which the trunnions 18 and 18 are arranged becomes the first arc 11 described above. In addition, the second arc 12 has a center on the central axis S2 orthogonal to the axis S1 connecting the trunnions 18 and 18 and is therefore formed in a direction orthogonal to the first arc 11. In addition, the curved portion 13 is arranged at a corner where the first circular arc 11 and the second circular 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). (1) Formula: 0.401×R1＜R3 _MIN ＜R1 (2) Formula: 0.401×R2＜R3 _MIN ＜R2 (3) Formula: R1≦R2

As described above, the minimum radius of curvature R3 _MIN of the curved portion 13 relative to the radius of curvature R1 of the first arc 11 and the radius of curvature R2 of the second arc 12 are set to R3 _MIN <R1, and R3 _MIN <R2, so The intersecting portion (corner) of the first arc 11 and the second arc 12 will protrude outward and become an approximately rectangular shape, and can be compared with the horizontal section of the pouring bucket body, which is circular, without changing the shape In the case of increasing the volume. In addition, in order to ensure the volume, the upper limit of the minimum radius of curvature R3 _MIN of the curved portion 13 should be 0.9×R1 and 0.9×R2.

In addition, the minimum radius of curvature R3 _MIN of the curved portion 13 with respect to the radius of curvature R1 of the first arc 11 and the radius of curvature R2 of the second arc 12 is set to 0.401×R1<R3 _MIN and 0.401×R2<R3 _MIN . That is, there is a lower limit that defines the minimum radius of curvature R3 _MIN of the curved portion 13. In this way, by specifying the lower limit of the minimum radius of curvature R3 _MIN of the curved portion 13, it is possible to suppress the stress concentration in the connecting portion of the first circular arc 11 and the curved portion 13, and the second circular arc 12 and the curved portion 13. Thereby, the deformation of the ladle body 10, the deterioration of the refractory layer 20, and the like can be suppressed.

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

In this embodiment, as shown in FIG. 4, the refractory layer 20 includes: a first refractory layer 21 arranged on the side of the ladle body 10, and a first refractory layer 21 arranged on the inner side of the first refractory layer 21 The second refractory layer 22. Here, in this embodiment, the first refractory layer 21 is formed by stacking refractory bricks. In addition, the second refractory layer 22 is formed of an amorphous refractory. In addition, in the area where the liquid surface of the molten metal is located, the second refractory layer 22 may be formed of refractory bricks in order to suppress melt loss. 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.

In addition, in the molten metal ladle 1 of this embodiment, after receiving molten iron or molten steel from a converter or a torpedo mixer, the hook of the overhead crane is locked on the trunnions 18, 18 for transportation, and Tilt around the trunnions 18 and 18, thereby transferring molten iron or molten steel to the container of the next step. In this way, the ladle 1 for molten metal is poured into and discharged from high-temperature molten iron or molten steel, so there will be serious thermal stress repetition. In addition, when a crack or the like occurs in the refractory layer 20 arranged inside the ladle body 10, the refractory layer 20 is repaired and used again.

According to the molten metal ladle 1 of this embodiment constructed as described above, the horizontal section of the ladle body 10 including the trunnion 18 is made into a non-circular shape, and is provided with: the first arc 11, which is connected The trunnion 18, 18 has a center on the axis S1, and the radius of curvature is R1, and includes a portion orthogonal to the trunnion 18; the second arc 12 has a center on the central axis S2 orthogonal to the axis S1, and The radius of curvature is R2 and includes the part orthogonal to the central axis S2; and the curved portion 13, which connects the first arc 11 and the second arc 12, and the minimum radius of curvature is R3 _MIN , and the minimum curvature of the curved portion 13 The radius R3 _MIN is set to R3 _MIN &lt; R1, R3 _MIN &lt; R2, and therefore has a horizontal cross-section approximately rectangular shape, and can be formed into a circular pouring bucket body with respect to the horizontal cross-section to expand the bucket volume.

In addition, the minimum radius of curvature R3 _MIN of the curved portion 13 is set to 0.401×R1<R3 _MIN and 0.401×R2<R3 _MIN . Therefore, the minimum radius of curvature R3 _{MIN of the} curved portion 13 does not become too small, and the first circle can be suppressed. The stress concentration in the connecting portion of the arc 11 and the curved portion 13 and the second circular arc 12 and the curved portion 13 can suppress the deformation of the ladle body 10 or the deterioration of the refractory layer 20. Thereby, the number of repairs of the molten metal ladle 1 can be reduced.

In addition, in this embodiment, the refractory layer 20 includes: a first refractory layer 21 arranged on the side of the ladle body 10, and a second refractory layer 22 arranged on the inner side of the first refractory layer 21 When the first refractory layer 21 is composed of refractory bricks, and the second refractory layer 22 is composed of unshaped refractories, it is possible to suppress the influence of the first refractory layer 21 disposed on the side of the pouring bucket body 10 The stress is concentrated, and the life of the first refractory layer 21 can be further extended. In addition, even if stress acts on the refractory layer 20 to cause cracks, the propagation of the cracks to the first refractory layer 21 made of refractory bricks can be suppressed, and only the inner side of the first refractory layer 21 can be repaired. The second refractory layer 22 may be sufficient. Since the second refractory layer is composed of monolithic refractories, it can be repaired relatively easily and the repair cost can be further reduced.

As mentioned above, although the ladle for molten metal of embodiment of this invention was specifically demonstrated, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of this invention. For example, in this embodiment, although a molten metal ladle having a trunnion of the structure shown in FIG. 1 is used as an example, it is not limited to this, and it may be a trunnion having other structures. Things.

In addition, in the present embodiment, although the description has been made with regard to holding and transferring molten iron and molten steel, the present invention is not limited to this, and may be used to process other molten metals. In addition, in this embodiment, although the refractory layer has been described as having a first refractory layer and a second refractory layer, it is not limited to this, and it may be a thing having a single refractory layer. , And can also have more than 3 refractory layers. Example

Hereinafter, the results of experiments conducted to confirm the effects of the present invention will be described.

>Example 1> As an example of the present invention, the ladle for molten metal described in the above embodiment was prepared. In addition, the curvature radius R1 of the first arc is 4170 mm, the curvature radius R2 of the second arc is 4170 mm, and the minimum curvature radius R3 _{MIN of the} curved portion is 1700 mm. That is, it is made to satisfy 0.401×R1<R3 _MIN <R1, 0.401×R2<R3 _MIN <R2, R1≦R2. As a comparative example, the curvature radius R1 of the first arc is 4170 mm, the curvature radius R2 of the second arc is 4170 mm, and the minimum curvature radius R3 _{MIN of the} curved portion is 1150 mm. That is, it is made to have a relationship of R3 _MIN <0.401×R1 and R3 _MIN <0.401×R2.

Using the molten metal ladle of the present example and the comparative example, the minimum value of the remaining thickness of the refractory layer after use was measured. In Figure 5, the initial thickness of the present invention and the comparative example is set to "1", and the relative value is displayed: when the number of uses of the present invention to reach the service life of the refractory is set to 1, in the comparative example The relationship between the number of uses of the service life of the refractory and the minimum value of the remaining thickness of the refractory layer. As shown in Fig. 5, it was confirmed that the molten metal ladle of the example of the present invention has a thicker remaining thickness of the refractory layer after use than the molten metal ladle of the comparative example, which can extend the service life. In addition, in the molten metal ladle of the example of the present invention, the volume of the ladle can be enlarged compared to the molten metal ladle having a circular horizontal cross section.

>Example 2> As test Nos. A to H, molten metal ladles were prepared, the shape of which was in a horizontal cross-section including the trunnion 18, provided with: a first arc with a center on the axis connecting the trunnion , And the radius of curvature is R1 and includes the part orthogonal to the aforementioned trunnion; the second arc has a center on the central axis orthogonal to the aforementioned axis, and the radius of curvature is R2, and includes the part orthogonal to the aforementioned central axis The part; and the curved part, connecting the first arc and the second arc, and the minimum radius of curvature is R3 _MIN . The relationship between R1, R2, R3 _MIN is shown in Table 1. In addition, the ratio t2/t1 of the thickness t1 of the first refractory layer (refractory brick) to the thickness t2 of the second refractory layer (unshaped refractory) is shown in Table 1.

The molten steel was transferred using the ladle for molten metal. The effective volume of the pouring bucket at this time, the number of times of use, the minimum value of the remaining thickness of the refractory layer, and whether the refractory layer in the curve part is cracked were evaluated. In addition, various evaluations are relative evaluations based on Test A (=1). The evaluation results are shown in Table 1.

※t2/t1 ：第1耐火物層(耐火磚)的厚度t1與第2耐火物層(不定形耐火物)的厚度t2之比[Table 1]

※T2/t1: The ratio of the thickness t1 of the first refractory layer (refractory brick) to the thickness t2 of the second refractory layer (unshaped refractory)

In the test No.G where R3 _MIN =0.3×R1, R3 _MIN =0.3×R2 is made, and the test No.H where R3 _MIN =0.25×R1, R3 _MIN =0.25×R2 is made, the curve part is The refractory layer has cracked.

In test Nos. B to F satisfying 0.401×R1<R3 _MIN ＜R1, 0.401×R2＜R3 _MIN ＜R2, compared with test No. A in which the horizontal section is formed in a circular shape, the effective volume is larger. In addition, it is possible to suppress the occurrence of cracks in the refractory layer in the curved portion. In addition, after comparing NoE and No.F of R3 _MIN =0.401×R1 and R3 _MIN =0.401×R2, the thickness t1 of the first refractory layer (refractory brick) is compared with the second refractory layer (unshaped refractory In No. E where the ratio t2/t1 of the thickness t2 is set to 1, compared to No. F where t2/t1 is set to 0.5, the number of times the refractory is used until the remaining thickness of the refractory layer reaches 40mm is Increased, and the life of the refractory layer can be extended. Industrial availability

According to the present invention, it is possible to provide a molten metal ladle which can expand the volume of the molten metal ladle, and can suppress the thermal stress acting on the molten metal ladle to reduce the number of repairs.

1: Pouring bucket for molten metal 10: Pouring bucket body 11: The first arc 12: 2nd arc 13: Curved part 18: Trunnion 20: Refractory layer 21: The first refractory layer 22: The second refractory layer R1, R2, R3: radius of curvature S1: axis S2: Central axis t1, t2: thickness

Fig. 1 is a side explanatory view showing an example of a molten metal ladle according to an embodiment of the present invention. Fig. 2 is an upper surface explanatory view showing an example of the molten metal ladle according to the embodiment of the present invention. Fig. 3 is an explanatory view showing the horizontal cross-sectional shape of the ladle body of the ladle for molten metal according to the embodiment of the present invention. Fig. 4 is an explanatory view showing the structure of the refractory layer in the molten metal ladle according to the embodiment of the present invention. Figure 5 is a graph showing the results of Example 1.

11: The first arc

12: 2nd arc

13: Curved part

R1, R2, R3: radius of curvature

S1: axis

S2: Central axis

Claims (2)

A ladle for molten metal has: a ladle body and a refractory layer arranged on the inside of the ladle body, and trunnions are provided on both sides of the ladle body, the ladle for molten metal is characterized by : The horizontal section of the pouring bucket body including the trunnion is made into a non-circular shape, and is provided with: a first arc, which has a center on the axis connecting the trunnion, and has a radius of curvature of R1, and includes The part orthogonal to the trunnion; the second arc has a center on the central axis orthogonal to the aforementioned axis, and has a radius of curvature of R2, and includes a part orthogonal to the aforementioned central axis; and a curved part connecting the aforementioned first the second circular arc circular arc, and a minimum radius of curvature R3 _MIN, and, the first radius of the arc of curvature R1, the radius of curvature of the second arc R2, the minimum radius of curvature of the curved portion satisfies the following R3 _MIN (1) Formula (1) to (3) Formula, (1) Formula: 0.401×R1<R3 _MIN <R1 (2) Formula: 0.401×R2<R3 _MIN <R2 (3) Formula: R1≦R2. The molten metal ladle of claim 1, wherein the refractory layer comprises: a first refractory layer arranged on the side of the ladle body, and a second refractory layer arranged on the inner side of the first refractory layer layer, The first refractory layer is composed of refractory bricks, and the second refractory layer is composed of amorphous refractories.

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