Nozzle-shaped refractory

Abstract

To suppress edge cracking while maintaining the flow controllability of molten metal for an extended period of time.SOLUTION: A nozzle shape refractory has an upper nozzle 10, a slide plate unit 20 including a plurality of mutually slidable plates, and a lower nozzle, in this order, and has an inner hole 40 inside them, where a joint 50 is provided in at least one of a connection between the upper nozzle 10 and the slide plate unit 20, and a connection between the slide plate unit 20 and the lower nozzle, the average thickness of the joints 50 in the inner region 53 that is at least a part of the portion of the joints 50 in contact with the inner hole 40 is greater than the average thickness of the joints 50 in regions other than the inner region 53.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a nozzle-shaped refractory. [Background technology]

[0002] Nozzle-shaped refractories equipped with slide plate units are commonly used as outlets for molten metal flow from vessels such as ladles and tundishes. In this type of refractory, the flow rate of molten metal is adjusted by adjusting the opening of the flow passage by sliding the plates that make up the slide plate unit. Cylindrical refractories are typically placed above and below the slide plate unit, and mortar joints filled with refractory mortar are typically provided in the gaps between the slide plate units and the adjacent refractories.

[0003] In nozzle-shaped refractories, high-temperature molten metal flows through the inner bore, creating a temperature difference between the outer periphery and the inner bore, which can lead to cracks in the refractory due to thermal stress. Edge cracks originate at the ridges (edges) between the inner bore surface and the sliding surface, and are caused by thermal expansion of the refractory along the direction of molten metal flow. Because the area where an edge crack occurs may break off as the slide plate unit slides, and because the broken area may initiate further damage, various studies have been conducted to prevent edge cracks.

[0004] For example, in the plate brick disclosed in Japanese Patent Laid-Open No. 11-245019 (Patent Document 1), a notch is provided in the edge portion that forms the boundary between the sliding surface of the slide plate and the inner bore, thereby alleviating stress caused by thermal expansion in the central axis direction of the inner bore and suppressing the occurrence of edge cracks. Japanese Patent Laid-Open No. 11-57989 (Patent Document 2) discloses a plate brick with a recess in the edge portion, which employs a similar technical concept to that of Patent Document 1. In addition, in the sliding nozzle plate disclosed in Japanese Patent Laid-Open No. 2-175068 (Patent Document 3), a ring-shaped refractory material is disposed in the inner bore, and the base into which the ring is fitted is formed from a material with a higher thermal expansion coefficient than the ring material, thereby alleviating stress caused by heating the inner bore and suppressing the occurrence of radial cracks that extend from the inner bore toward the outer periphery. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-245019 [Patent Document 2] Japanese Patent Application Publication No. 11-57989 [Patent Document 3] Japanese Patent Application Publication No. 2-175068 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technologies of Patent Document 1 and Patent Document 2, the joint space necessary for relieving thermal stress is adjacent to the inner bore, and molten steel may enter the space, causing metal leakage. This is the same condition as when the edge of the slide plate is chipped due to crack damage, which reduces the controllability of the molten metal flow rate and can cause problems such as poor stopping and steel leakage. Furthermore, the technology of Patent Document 3 could not be expected to suppress edge cracks.

[0007] Therefore, it is necessary to develop a nozzle-shaped refractory that can suppress edge cracks and maintain the flow rate control of molten metal for a long period of time. [Means for solving the problem]

[0008] The nozzle-shaped refractory of the present invention is a nozzle-shaped refractory having an upper nozzle, a slide plate unit including a plurality of plates that can slide relative to each other, and a lower nozzle, arranged in that order, and having an inner hole on the inside, characterized in that a joint is provided in at least one of the connection portion between the upper nozzle and the slide plate unit and the connection portion between the slide plate unit and the lower nozzle, and the average thickness of the joint in an inner region, which is at least a part of the part of the joint that contacts the inner hole, is greater than the average thickness of the joint outside the inner region.

[0009] This configuration reduces thermal stress by thickening the joints around the inner bore, thereby suppressing edge cracks. Furthermore, in areas where thermal stress relief is less necessary, the joints are made thinner to prevent the intrusion of molten steel and outside air, allowing for the control of the molten metal flow rate to be maintained for a long period of time.

[0010] Preferred embodiments of the present invention will be described below, but the scope of the present invention is not limited to the preferred embodiments described below.

[0011] In one aspect of the nozzle-shaped refractory according to the present invention, the average thickness of the joints in the inner region is preferably 1.3 to 3.0 times the average thickness of the joints in regions other than the inner region.

[0012] This configuration makes it easy to achieve both thermal stress relief and gas sealing properties.

[0013] In one aspect of the nozzle-shaped refractory according to the present invention, the radial width of the inner region is preferably 0.1 times or more the diameter of the inner hole and 0.5 times or less the radial width of the joint.

[0014] This configuration makes it easy to achieve both thermal stress relief and gas sealing properties.

[0015] In one aspect of the nozzle-shaped refractory according to the present invention, the plates include a first plate with which the joint is in contact and a second plate that slides against the first plate, and the inner region is preferably provided in a portion of the joint that is in contact with the inner hole, on the side in the direction in which the second plate moves relative to the first plate when closing the inner hole.

[0016] According to this configuration, the inner region is provided in a portion where the need to relieve thermal stress is particularly great, so edge cracks can be more reliably suppressed.

[0017] In one aspect of the nozzle-shaped refractory according to the present invention, it is preferable that the inner region is provided at least in a region where the deflection angle is equal to or greater than -45° and equal to or less than 45° in a polar coordinate system where the center of the inner hole with which the joint is in contact is the origin and the direction of the relative movement is 0°.

[0018] This configuration can further suppress edge cracks.

[0019] Further features and advantages of the present invention will become more apparent from the following description of exemplary and non-limiting embodiments, which is given with reference to the drawings. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a vertical cross-sectional view of a continuous casting nozzle according to an embodiment. FIG. [Figure 2] FIG. 2 is a vertical cross-sectional view showing the structure of a mortar joint of the continuous casting nozzle according to the embodiment. [Figure 3] FIG. 10 is a vertical cross-sectional view showing the structure of a mortar joint of a continuous casting nozzle according to a modified example. [Figure 4] FIG. 10 is a diagram showing the arrangement of mortar joints in a continuous casting nozzle according to a modified example. [Figure 5] FIG. 1 is a vertical cross-sectional view showing the structure of the mortar joints of Examples 2 and 8. [Figure 6] FIG. 1 is a vertical cross-sectional view showing the structure of the mortar joints of Examples 3 and 9. [Figure 7] FIG. 10 is a vertical cross-sectional view showing the structure of the mortar joint of Example 4. [Figure 8] FIG. 10 is a vertical cross-sectional view showing the structure of a mortar joint of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the nozzle-shaped refractory according to the present invention will be described with reference to the drawings. In the following, an example will be described in which the nozzle-shaped refractory according to the present invention is applied to a continuous casting nozzle 1 (FIG. 1) for pouring molten steel tapped from a ladle (not shown) into a tundish (not shown).

[0022] [Basic structure of continuous casting nozzle] The continuous casting nozzle 1 according to this embodiment includes an upper nozzle 10, a slide plate unit 20, and a lower nozzle 30, in this order from top to bottom (FIG. 1). In this specification, the "vertical direction" refers to the vertical direction in FIG. 1 unless otherwise specified. In this specification, the "horizontal direction" refers to the left-right direction in FIG. 1 unless otherwise specified.

[0023] A through hole is provided inside each unit member constituting the upper nozzle 10, the slide plate unit 20, and the lower nozzle 30, and these through holes are connected to form an inner hole 40. The slide plate unit 20 includes a fixed plate 21 (an example of a plate) connected to the upper nozzle 10, and a sliding plate 22 (an example of a plate) connected to the lower nozzle 30. Mortar joints 50 (51, 52) (an example of a joint) are provided at the connection between the upper nozzle 10 and the slide plate unit 20 (fixed plate 21) and at the connection between the slide plate unit 20 (sliding plate 22) and the lower nozzle 30.

[0024] The continuous casting nozzle 1 is provided below the ladle. Therefore, molten steel tapped from the ladle moves downward by gravity and is poured into the tundish through the continuous casting nozzle 1 (inner bore 40). As will be described in detail later, the continuous casting nozzle 1 is provided with a slide gate device that can control the flow of molten steel by sliding a sliding plate 22 that constitutes a slide plate unit 20. In this embodiment, the sliding plate 22 is connected to the lower nozzle 30, so that the sliding plate 22 and the lower nozzle 30 move together when the slide gate device is opened or closed.

[0025] The upper nozzle 10, the slide plate unit 20, and the lower nozzle 30 are all made of refractory material. The refractory material used here may be a dense refractory material conventionally used in continuous casting nozzles. Examples of the dense refractory material include those commonly used in this field, and examples of the substrate include oxide-based materials commonly used as refractories, such as alumina, mullite, spinel, magnesia, and zirconia, as well as materials combining these oxides with non-oxides such as carbon.

[0026] The mortar joints 50 (51, 52) are made of a mortar material that is conventionally used in continuous casting equipment, such as a thermosetting fireproof mortar.

[0027] The upper nozzle 10 is a cylindrical body connected to the underside of the ladle, and has a protrusion 11 at its lower end. The fixed platen 21 has a plate-like shape with a through-hole in part of it, and has a recess 23 on its upper surface. The upper nozzle 10 and the fixed platen 21 are connected such that the protrusion 11 fits into the recess 23. A mortar joint 51 is formed between the protrusion 11 and the recess 23.

[0028] The lower nozzle 30 is a cylindrical body connected to the lower side of the slide plate unit 20, and a recess 31 is provided at the upper end of the lower nozzle 30. The sliding plate 22 has a shape in which a through-hole is provided in part of a plate-like member, and a protrusion 24 is provided on the lower surface of the sliding plate 22. The sliding plate 22 and the lower nozzle 30 are connected in such a manner that the protrusion 24 and the recess 31 fit together. A mortar joint 52 is formed between the protrusion 24 and the recess 31.

[0029] The mortar joint 51 has a shape that follows the shapes of the convex portion 11 and the concave portion 23 (FIG. 2). An inner region 53 is provided in the mortar joint 51 at a portion that contacts the inner hole 40. In this embodiment, the inner region 53 is provided around the entire circumference of the inner hole 40. For the sake of distinction, the region of the mortar joint 51 other than the inner region 53 is referred to as a normal region 54.

[0030] Mortar joint 52 has a shape that follows the shapes of convex portion 24 and concave portion 31. Like mortar joint 51, an inner region is provided in the portion that contacts inner hole 40. The effects and preferred aspects of mortar joint 52 are the same as those of mortar joint 51. However, the dimensional conditions related to the average thickness and width of the inner region of mortar joint 52 may be the same as or different from the dimensional conditions related to the average thickness and width of the inner region of mortar joint 51.

[0031] The inner region 53 is located on the inside (the portion adjacent to the inner bore 40) where relatively large thermal stresses are likely to be a problem, and serves to absorb the thermal expansion of the refractory material along the extension direction of the inner bore 40 (the vertical direction in FIG. 1). The refractory mortar that makes up the mortar joints 50 (51, 52) is more elastic than the refractory materials that make up the upper nozzle 10, slide plate unit 20, and lower nozzle 30. Therefore, even if stress that compresses the mortar joints 50 (51, 52) in the vertical direction due to thermal expansion of the refractory material occurs, the mortar joints 50 (51, 52) can elastically deform and alleviate the stress. To expect this effect to occur, it is advantageous for the mortar joints 50 (51, 52) to be thick.

[0032] On the other hand, the refractory mortar that forms the mortar joints 50 (51, 52) is inferior to the refractory materials that form the upper nozzle 10, the slide plate unit 20, and the lower nozzle 30 in terms of preventing the intrusion of molten steel (metal injector) flowing through the inner bore 40 and the intrusion of outside air from outside the continuous casting nozzle 1. Therefore, in terms of preventing the intrusion of molten steel and outside air, it is advantageous for the mortar joints 50 (51, 52) to be thin.

[0033] In the continuous casting nozzle 1 according to this embodiment, the mortar joints 50 (51, 52) are locally provided thick in the area where thermal stress is likely to be a problem, i.e., the inner region 53, so as to alleviate the thermal stress applied from above and below this area. On the other hand, in the area where thermal stress is less likely to be a problem, i.e., the normal region 54, the mortar joints 50 (51, 52) are provided thin to prevent the intrusion of molten steel and external air. In this way, by providing the mortar joints 51 with a thickness according to the required function in each area, it is possible to both suppress edge cracking by alleviating thermal stress and extend the life of the nozzle by preventing the intrusion of molten steel and external air.

[0034] The average thickness of the mortar joints 50 (51, 52) in the inner region 53 is greater than the average thickness of the mortar joints 50 (51, 52) in the normal region 54. More specifically, it is preferable that the average thickness of the mortar joints 50 (51, 52) in the inner region 53 be 1.3 to 3.0 times the average thickness of the mortar joints in regions other than the inner region. When this ratio is 1.3 or more, the effect of alleviating thermal stress occurring around the inner hole 40 is particularly likely to be realized. Furthermore, when this ratio is 3.0 or less, it is easy to ensure a sufficient level of gas sealing performance of the mortar joints 50 (51, 52). In addition, since the contact area between the molten steel and the mortar material can be reduced, it is easy to suppress joint melting damage.

[0035] The radial width W1 of the inner region 53 is preferably at least 0.1 times the diameter D of the inner hole 40. When the width W1 is at least 0.1 times the diameter D, the effect of alleviating thermal stress occurring around the inner hole 40 is particularly likely to be realized. The radial width W1 of the inner region 53 refers to the width along the radial direction of the inner hole 40 from the end of the inner region 53 on the inner hole 40 side to the position where the thickness of the mortar joint 50 (51, 52) becomes the same as the thickness in the normal region 54.

[0036] Furthermore, the radial width W1 of the inner region 53 is preferably 0.5 times or less the radial width W of the entire mortar joint 50 (51, 52). When the width W1 is 0.5 times or less the width W, it is easy to ensure a sufficient level of gas sealing performance of the mortar joint 51. In other words, it is preferable to provide the inner region 53 with a limit of half the width of the mortar joint 50 (51, 52).

[0037] The suitable dimensional conditions for the average thickness and width W1 of the inner region 53 can be achieved, for example, by providing a notch in the portion of the recess 23 corresponding to the inner region 53 so as to satisfy the above conditions.

[0038] [Modification] Next, a modified example of the slide plate unit 20 will be described. In the above embodiment, a configuration in which the inner region 53 is provided around the entire circumference of the inner hole 40 has been exemplified, but the inner region may be provided facing only a portion of the inner hole. In the slide plate unit 20A according to the modified example shown in FIG. 3, the inner region 56 is provided only on the left side of the mortar joint 55 in the drawing, and the thickness of the mortar joint 55 is uniform on the right side of the drawing. This modification is realized by the shape of the fixed plate 25 being different from that of the above embodiment (fixed plate 21), more specifically, the shape of the recess 26 being different from that of the above embodiment (recess 23). The configuration of the slide plate 22 is the same as that of the above embodiment.

[0039] Here, an inner region 56 is provided on the side of the fixed platen 25 (an example of a first plate) with which the mortar joint 55 is in contact, in the direction S1 in which the sliding platen 22 (an example of a second plate) sliding against the fixed platen 25 moves relative to the sliding platen 22 when closing the inner hole 40. Fig. 4 is a schematic diagram showing the positional relationship of the fixed platen 25, the sliding platen 22, and the inner region 56 of the mortar joint 55 in this modified example, viewed from above and below. In a polar coordinate system in which the center O of the inner hole 40 with which the mortar joint 51 is in contact is the origin and the direction S1 in which the sliding platen 22 moves relative to the sliding platen 22 when closing the inner hole 40 is set to 0°, the inner region 56 is provided with a deflection angle θ in the range of ±45°.

[0040] When the sliding platen 22 is moved in the direction S to partially close the inner bore 40, the lower surface 27 of the stationary platen 25 is exposed to the inner bore 40 in a region centered on the declination angle of 0° in the polar coordinate system ( FIG. 3 ). Therefore, in this region, the stationary platen 25 comes into contact with the molten steel not only at the inner circumferential surface 28 but also at the lower surface 27. Therefore, this region of the stationary platen 25 receives a larger amount of heat from the molten steel than other parts, and thermal stress is particularly likely to be a problem. Therefore, there is a particularly strong need to provide the inner region 56 in this region.

[0041] On the other hand, in other areas, the thermal stress may fall within the allowable range without any particular adjustment to the thickness of mortar joint 55. Therefore, in other areas, priority is given to suppressing outside air intake, and measures to thicken mortar joint 55 are not taken.

[0042] For simplicity, the configuration of the sliding platen 22 has been described as being the same as in the above embodiment, but the mortar joint between the sliding platen and the lower nozzle can also be provided with a measure of only partially providing an inner region. However, for the mortar joint between the sliding platen and the lower nozzle, the direction S2 (FIG. 3) of relative movement of the fixed platen when closing the inner hole should be treated as 0° in the polar coordinate system, and therefore it should be noted that the location where it is highly necessary to provide an inner region appears reversed left and right compared to the mortar joint 55 in the above modified example.

[0043] In both the mortar joint between the upper nozzle and the slide plate unit and the mortar joint between the slide plate unit and the lower nozzle, as in the above-described modified example, it is preferable that an inner region be provided on the side of the first plate with which the mortar joint is in contact, in the direction in which the second plate that slides against it moves relative to the first plate when closing the inner hole. Furthermore, it is even more preferable that the inner region be provided in at least a region with a deflection angle of -45° to 45° in a polar coordinate system in which the direction of relative movement is set to 0°.

[0044] Other Embodiments Finally, other embodiments of the nozzle-shaped refractory according to the present invention will be described. Note that the configurations disclosed in the following embodiments can be applied in combination with the configurations disclosed in other embodiments, unless a contradiction occurs.

[0045] In the above embodiment, the slide plate unit 20 is a combination of a fixed platen 21 and a sliding platen 22. However, in the nozzle-shaped refractory according to the present invention, the number of plates constituting the slide plate unit may be any number of plates equal to or greater than two. For example, the present invention may also be implemented as a nozzle-shaped refractory including a slide plate unit having, in order from top to bottom, a fixed platen, a sealing platen, and a sliding platen.

[0046] In the above embodiment, an example has been described in which an inner region is provided in both the mortar joint 51 between the upper nozzle 10 and the fixed platen 21 and the mortar joint 52 between the sliding platen 22 and the lower nozzle 30. However, in the nozzle-shaped refractory according to the present invention, it is sufficient that a joint having an inner region is provided in at least one of the connection portion between the upper nozzle and the slide plate unit and the connection portion between the slide plate unit and the lower nozzle, and it is not necessarily required that a joint having an inner region is provided in both of them.

[0047] In the above embodiment, an example has been described in which the inner region 53 is formed by providing a notch in a part of the recess 23. However, in the nozzle-shaped refractory according to the present invention, the method of forming the inner region is not limited to the above example, and a notch may be provided in one or both of the upper nozzle and the slide plate unit (or the slide plate unit and the lower nozzle) that contact the joint.

[0048] In the above embodiment, a configuration in which the thickness of the mortar joint 51 is uniform in the inner region 53 has been described as an example. However, the thickness of the joint does not have to be uniform within the inner region. Note that the thickness of the joint may or may not be uniform within the normal region as well.

[0049] The joints in the present invention are not limited to mortar joints, but may be joints made of materials commonly used as joint materials in this field. Examples of such materials include refractory ceramic fibers. Even when mortar joints are used, the construction method is not limited. Mortar may be applied to the connection between the nozzle and the slide plate unit when assembling the nozzle-shaped refractory, or mortar pre-formed into a packing shape may be placed in the connection.

[0050] In the above embodiment, an example has been described in which the convex portion 11 of the upper nozzle 10 is fitted into the concave portion 23 of the fixed platen 21, and the concave portion 31 of the lower nozzle 30 is fitted into the convex portion 24 of the sliding platen 22. However, in the nozzle-shaped refractory according to the present invention, the shape of the connection portion between the upper nozzle or lower nozzle and the slide plate unit is not particularly limited. Examples include a fitting shape in which the nozzle is convex and the slide plate unit is concave (one example is the fitting between the convex portion 11 of the upper nozzle 10 and the concave portion 23 of the fixed platen 21), a fitting shape in which the nozzle is concave and the slide plate unit is convex (one example is the fitting between the concave portion 31 of the lower nozzle 30 and the convex portion 24 of the sliding platen 22), and a structure in which both the nozzle and the slide plate unit are flat.

[0051] Regarding other configurations, it should be understood that the embodiments disclosed in this specification are illustrative in all respects and that the scope of the present invention is not limited thereby. Those skilled in the art will easily understand that appropriate modifications are possible without departing from the spirit of the present invention. Therefore, other embodiments modified without departing from the spirit of the present invention are naturally included in the scope of the present invention. [Example]

[0052] The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

[0053] [Nozzle-shaped refractory] In each of the examples and comparative examples, a nozzle-shaped refractory material was fabricated with a shape conforming to FIG. 1. However, in all examples, the diameter of the inner hole was 90 mm, and the shape of the mortar joint between the upper nozzle and the slide plate unit was changed for each example. The shape of the mortar joint in each example will be described later. The conditions for the refractories constituting the upper nozzle, slide plate unit, and lower nozzle, and the mortar material constituting the mortar joint were the same as those in the above-mentioned embodiment. Furthermore, the mortar joint between the slide plate unit and the lower nozzle was of a constant thickness in all examples.

[0054] [Evaluation method] The nozzle-shaped refractories of each of the Examples and Comparative Examples were used as slide valve devices attached to the bottom of a ladle. Each example was used multiple times, counting the number of uses until all of the molten steel filled in the ladle was discharged, and the number of uses was counted until damage was observed and the ladle was deemed unusable.

[0055] [Shapes of each example] Example 1 The shape of the mortar joint was the shape shown in Figure 2 (mortar joint 51). In this example, the average thickness of the mortar joint in the inner region was 4.0 mm, and the average thickness of the mortar joint in the normal region was 2.0 mm. In other words, the average thickness of the mortar joint in the inner region was 2.0 times the average thickness of the mortar joint in the normal region. In this example, the thickness of the mortar joint was uniform (4.0 mm) throughout the entire inner region. Furthermore, the radial width of the inner region was 15 mm, and the radial width of the entire mortar joint was 50 mm. In other words, the radial width of the inner region was 0.17 times the diameter of the inner hole and 0.30 times the radial width of the entire mortar joint.

[0056] Example 2 The shape of the mortar joint was the shape shown in FIG. 5 (mortar joint 51A). Example 2 differs from Example 1 in that notches were provided in both the upper nozzle and the slide plate unit. In this example, the average thickness of the mortar joint in the inner region was 5.0 mm, and the average thickness of the mortar joint in the normal region was 2.0 mm. That is, the average thickness of the mortar joint in the inner region was 2.5 times the average thickness of the mortar joint in the normal region. In this example, the thickness of the mortar joint was uniform (5.0 mm) throughout the entire inner region. Furthermore, the radial width of the inner region was 15 mm, and the radial width of the entire mortar joint was 50 mm. That is, the radial width of the inner region was 0.17 times the diameter of the inner hole and 0.30 times the radial width of the entire mortar joint.

[0057] Example 3 The shape of the mortar joint was the shape shown in FIG. 6 (mortar joint 51B). Example 3 differs from Example 1 in that the slide plate unit has two-stage notches. In this example, the average thickness of the mortar joint in the inner region was 4.8 mm, and the average thickness of the mortar joint in the normal region was 2.0 mm. That is, the average thickness of the mortar joint in the inner region was 2.4 times the average thickness of the mortar joint in the normal region. Furthermore, the radial width of the inner region was 20 mm, and the radial width of the entire mortar joint was 50 mm. That is, the radial width of the inner region was 0.22 times the diameter of the inner hole and 0.40 times the radial width of the entire mortar joint. In this example, the inner region was divided into two zones. The region directly adjacent to the inner hole had a radial width of 10 mm and a mortar joint thickness of 6.0 mm. The following area has a radial width of 10 mm and a mortar joint thickness of 3.5 mm.

[0058] Example 4 The shape of the mortar joint was the shape shown in FIG. 7 (mortar joint 51C). Example 4 differs from Example 1 in that the slide plate unit has an inclined notch. In this example, the average thickness of the mortar joint in the inner region was 3.5 mm, and the average thickness of the mortar joint in the normal region was 2.0 mm. That is, the average thickness of the mortar joint in the inner region was 1.8 times the average thickness of the mortar joint in the normal region. Furthermore, the radial width of the inner region was 20 mm, and the radial width of the entire mortar joint was 50 mm. That is, the radial width of the inner region was 0.22 times the diameter of the inner hole and 0.40 times the radial width of the entire mortar joint. Note that in this example, the thickness of the mortar joint in the inner region gradually decreased from the portion directly in contact with the inner hole toward the outside, from 5.0 mm in the portion directly in contact with the inner hole to 2.0 mm at the outer end of the inner region.

[0059] Example 5 The shape of the mortar joint was the shape shown in Figures 3 and 4 (mortar joint 55). However, θ was set to 60°. In this example, the average thickness of the mortar joint in the inner region was 4.0 mm, and the average thickness of the mortar joint in the normal region was 2.0 mm. In other words, the average thickness of the mortar joint in the inner region was 2.0 times the average thickness of the mortar joint in the normal region. In this example, the thickness of the mortar joint was uniform (4.0 mm) throughout the entire inner region. Furthermore, the radial width of the inner region was 15 mm, and the radial width of the entire mortar joint was 50 mm. In other words, the radial width of the inner region was 0.17 times the diameter of the inner hole and 0.30 times the radial width of the entire mortar joint.

[0060] Example 6 The same as in Example 5 was performed except that θ was set to 45°.

[0061] Example 7 The radial width of the inner region was set to 5.0 mm, and the other factors were the same as in Example 1. In this example, the radial width of the inner region was 0.056 times the diameter of the inner hole and 0.10 times the radial width of the entire mortar joint.

[0062] Example 8 The radial width of the inner region was set to 28 mm, and other factors were the same as in Example 1. In this example, the radial width of the inner region was 0.31 times the diameter of the inner hole and 0.56 times the radial width of the entire mortar joint.

[0063] Example 9 The thickness of the mortar joints in the inner region was set to 2.5 mm, and other factors were the same as in Example 1. In this example, the average thickness of the mortar joints in the inner region was 1.3 times the average thickness of the mortar joints in the normal region.

[0064] Example 10 The same as in Example 5 was used except that θ was set to 30°.

[0065] (Comparative Example) The shape of the mortar joint was the shape (mortar joint 51D) shown in Fig. 8. In this example, no inner region was provided in the mortar joint, and the thickness of the mortar joint was set to a uniform 2.0 mm.

[0066] [Evaluation results] The dimensional conditions for each example of the examples and comparative examples, and the number of times each example was used, are shown in Table 1. For comparison with Example 5 (θ=60°), Example 6 (θ=45°), and Comparative Example 5 (θ=30°), the other examples are shown in Table 1 with θ set to 180°.

[0067] Table 1: Examples and Comparative Examples [Table 1]

[0068] As shown in Table 1, in all of the Examples, the number of uses was longer than in the Comparative Examples. The increase in the number of uses was particularly remarkable in Examples 1 to 6 and 8. However, in Example 8, a slight decrease in steel quality was observed compared to Examples 1 to 6. This is thought to be because Example 8 absorbed more outside air than Examples 1 to 6. [Industrial Applicability]

[0069] The present invention can be utilized as a nozzle used in, for example, continuous casting or ingot casting. [Explanation of symbols]

[0070] 1: Continuous casting nozzle 10: Upper nozzle 11: Convex part 20: Slide plate unit 21:Fixed plate 22:Sliding plate 23: Recess 24: Convex part 30: Lower nozzle 31: Recess 40: Inner hole 50: Mortar joints 51: Mortar joint 52: Mortar joint 53 :Inner area 54: Normal area 20A: Slide plate unit (modified version) 25: Fixed platen (variant) 26: Recess (variant) 27: Bottom (variant) 28: Inner surface (modified example) 55: Mortar joint (variation) 56: Inner region (variant) S: Direction of relative movement of the sliding platen with respect to the fixed platen S2: Direction of relative movement of the fixed platen with respect to the sliding platen O: Center of inner hole θ: Declination angle

Claims

1. A nozzle-shaped refractory having an inner hole therein, the nozzle-shaped refractory including an upper nozzle, a slide plate unit including a plurality of plates slidable relative to each other, and a lower nozzle provided in this order, a joint is provided in at least one of a connection portion between the upper nozzle and the slide plate unit and a connection portion between the slide plate unit and the lower nozzle; A nozzle-shaped refractory material in which the average thickness of the joint in an inner region, which is at least a part of the portion of the joint in contact with the inner hole, is greater than the average thickness of the joint in a region other than the inner region.

2. 2. The nozzle-shaped refractory according to claim 1, wherein the average thickness of the joints in the inner region is 1.3 to 3.0 times the average thickness of the joints in the region other than the inner region.

3. 3. The nozzle-shaped refractory according to claim 1, wherein the radial width of the inner region is at least 0.1 times the diameter of the inner hole and at most 0.5 times the radial width of the joint.

4. As the plates, a first plate with which the joint is in contact and a second plate that slides against the first plate are provided, 3. The nozzle-shaped refractory according to claim 1, wherein the inner region is provided in a portion of the joint that contacts the inner hole, on a side in a direction in which the second plate moves relative to the first plate when closing the inner hole.

5. The nozzle-shaped refractory according to claim 4, wherein the inner region is provided in a region where the deflection angle is at least -45° or more and 45° or less in a polar coordinate system where the center of the inner hole with which the joint is in contact is the origin and the direction of the relative movement is 0°.

Images