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Abstract

To provide a mold capable of compensating for shrinkage of a solidified shell. [Solution] The mold of the present invention is a mold having an internal space into which molten steel can be poured, and is characterized in that it comprises a body having the internal space, and the inner surface of the body facing the internal space has a first inclined surface that inclines so as to move away from the outer surface, which is the opposite surface of the inner surface, as it progresses downward, and a second inclined surface that is located below the first inclined surface and inclines so as to move closer to the outer surface as it progresses downward.

Description

[Technical field]

[0001] The present invention relates to a mold, and more particularly to a mold capable of suppressing or preventing the occurrence of defects in a cast piece and damage to the mold. [Background technology]

[0002] A slab is produced by pouring molten steel into a mold having a specific internal shape and solidifying the molten steel within the mold. Generally, a rectangular mold having long and short sides is used. When molten steel is supplied into the mold, a solidified shell starts to form from the molten steel surface in the mold, and solidification proceeds downward, and the thickness of the solidified shell increases as solidification proceeds. When the molten steel solidifies inside the mold to form a solidified shell, solidification shrinkage occurs in the solidified shell. In particular, when the liquid phase molten steel transforms into a solid phase in the upper part of the mold, the solidified shell shrinks significantly. If such shrinkage of the solidified shell cannot be compensated for in the mold, an air layer or gap will be formed between the mold and the solidified shell. When a gap is formed, the heat transfer ability between the mold and the solidified shell or molten steel decreases, causing a phenomenon of delayed solidification, which leads to breakouts and defects in the cast slab.

[0003] In order to solve this problem, a method has been devised to slope the mold so that its width decreases as it moves downward. That is, the distance between a pair of short sides of the mold is arranged to decrease as it moves downward to compensate for the shrinkage of the solidified shell in the long side direction of the mold, and the distance between a pair of long sides of the mold is arranged to decrease as it moves downward to compensate for the shrinkage of the solidified shell in the short side direction of the mold. However, even in such a case, the shrinkage of the solidified shell cannot be sufficiently compensated for, and a gap still occurs between the mold and the solidified shell. In order to fully compensate for the solidification shrinkage in the upper part of the mold, the slope of the short side of the mold has been made larger, but in this case, friction occurs between the short side of the slab and the short side of the mold in the lower part of the mold, which causes wear on the mold, shortens the life of the mold, and deteriorates the quality of the slab. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Korean Patent Publication No. 10-2000-0008003 Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to provide a mold which is capable of compensating for the shrinkage of the solidified shell. Another object of the present invention is to provide a mold which has an improved compensation rate for shrinkage of the solidified shell. It is still another object of the present invention to provide a mold capable of suppressing or preventing the inner wall of the mold from being worn down by the cast piece. [Means for solving the problem]

[0006] The mold of the present invention is a mold having an internal space into which molten steel can be poured, and is characterized in that it comprises a body having the internal space, and the inner surface of the body facing the internal space has a first inclined surface that is inclined so as to move away from the outer surface, which is the opposite surface of the inner surface, as it progresses downward, and a second inclined surface that is provided below the first inclined surface and is inclined so as to move closer to the outer surface as it progresses downward.

[0007] The first inclined surface is an upper end P of the inner surface of the body. UThe second inclined surface extends from the upper end P of the inner surface of the body to a first point P1 that is spaced apart by a first distance S1. U A second point P2 spaced apart by a second distance S2 from the lower end P L It is preferable that the first distance S1 and the second distance S2 are shorter than the height H1 of the body. The first distance S1 may be greater than or equal to 15% and less than or equal to 25% of the height H1 of the body.

[0008] The first inclined surface is an upper end P of the inner surface of the body. U and the first point P1, the slope gradient changes based on a first inflection point IP1 between the first point P1 and the first inflection point IP1, and it is preferable that, in the first inclined surface, the angle formed between a lower region of the first inflection point IP1 and the outer surface is smaller than the angle formed between an upper region of the first inflection point IP1 and the outer surface. The first inflection points IP1 are provided in a plurality of points, and the first inflection points IP1 are located at the upper end P U and the first location P1. The second distance S2 is preferably 40% or more and 50% or less of the height H1 of the body.

[0009] The second inclined surface is a surface between the second portion P2 and the lower end P of the inner surface of the body. L It is preferable that the angle between the lower region of the second inflection point IP2 and the outer surface of the second inclined surface is larger than the angle between the upper region of the second inflection point IP2 and the outer surface of the second inclined surface. The second inflection points IP2 are provided in a plurality of places, and the plurality of second inflection points IP2 are located between the second point P2 and the lower end P L The position of the light source 10 can be different from that of the light source 10. It is preferable that an intermediate surface be provided between the first inclined surface and the second inclined surface, the intermediate surface being equidistant from the outer surface in the vertical direction.

[0010] The body comprises a pair of long side members, each extending in one direction and arranged opposite each other in a direction intersecting the extension direction, and a pair of short side members, each extending so as to intersect with the long side members and arranged opposite each other so as to seal the space between the pair of long side members, and it is preferable that the first and second inclined surfaces are provided on an inner surface of at least one of the short side members and the long side members. It is preferable that the distance between the pair of short side members is inclined so that it decreases as it progresses downward, and that the side surface of the short side member abutting the long side member is inclined toward the center of the width of the short side member as it progresses downward. The body may include protruding members protruding toward the internal space at both ends in an extension direction of the short side members so as to form chamfered surfaces at corners of a cast slab to be cast.

[0011] It is preferable that a convex member is provided which protrudes from the inner surface of either the long side member or the short side member toward the internal space, and the protruding length from the inner surface into the internal space decreases as it progresses downward, and the width of the convex member is shorter than the width of the body. The height of the protruding member is preferably shorter than the height of the body. The protruding member is disposed at the upper end P of the inner surface of the body. U It is preferable that the first distance S1 is longer than the first distance S1 and that the second distance S2 is shorter than the second distance S2.

[0012] The gradient of the protruding length of the protruding member decreasing as it advances downward is the upper end P Uand the third point P3, the gradient changes with respect to a third inflection point IP3 between the third point P4 and the third point P5, and in the convex member, it is preferable that an angle formed between a region below the third inflection point IP3 and the outer surface is larger than an angle formed between a region above the third inflection point IP3 and the outer surface. The third inflection points IP3 are provided in a plurality of points, and the third inflection points IP3 are located at the upper end P U and the third point P3 at different positions from each other. Effect of the Invention

[0013] According to an embodiment of the present invention, the mold of the present invention has an improved compensation rate for shrinkage of the solidified shell. That is, the inclined surface and the convex member provided on the inner surface of the body improve the compensation rate for shrinkage of the solidified shell in the long side direction and the short side direction. In particular, the compensation rate for shrinkage of the solidified shell in the upper part of the internal space of the mold is improved. Therefore, it is possible to suppress or prevent the generation of a gap between the inner surface of the mold and the solidified shell due to the shrinkage of the solidified shell, and it is possible to suppress or prevent the phenomenon of delayed solidification caused by this. As a result, it is possible to suppress or prevent the occurrence of defects on the surface of the cast slab and the occurrence of breakouts. Furthermore, the inclined surface provided on the inner surface of the mold can reduce friction between the inner surface of the mold and the cast piece, thereby extending the life of the mold. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a casting apparatus including a mold according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a three-dimensional view showing a mold according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is an exploded perspective view of the mold shown in FIG. 2. [Figure 4] 3 is a cross-sectional view seen from the "A" side in FIG. 2 to explain the arrangement of a pair of short side portions. FIG. [Diagram 5]This is a cross-sectional view of the short side of Figure 2 taken along B-B' and viewed from the "A" side. [Figure 6] FIG. 3 is a front view of the short side portion of FIG. 2 as viewed from the "C" side. [Figure 7] FIG. 1 is a view showing a mold according to a first embodiment of the present invention, in which (a) is a view showing an upper part of a solidified shell, and (b) is a view showing a lower part of the solidified shell. [Figure 8] FIG. 1 shows the configuration of a mold according to a first embodiment of the present invention, where (a) is a three-dimensional view of the short side, (b) is a front view of (a) viewed from the "D" side, (c) is a cross-sectional view of (a) cut along E-E' and viewed from the "F" side, and (d) is a cross-sectional view at each of positions (a), (b), and (c) in the vertical direction (Z-axis direction) of (c). [Figure 9] 1A and 1B are diagrams for explaining the extension length of the inner surface of the short side portion in the short side portion of the first embodiment of the present invention, where (a) is a diagram in which a curve is formed by a convex member arranged on the inner surface of the short member, and (b) is a diagram in which the inner surface of the short member is a straight line. [Figure 10] FIG. 4 is a diagram showing a short side portion of a mold according to a first modified example of the first embodiment. [Figure 11] FIG. 11 is a diagram showing a short side portion of a mold according to a second modified example of the first embodiment. [Figure 12] FIG. 13 is a diagram showing a short side portion of a mold according to a third modified example of the first embodiment. [Figure 13] 13A and 13B are diagrams showing the short side of a mold for a fourth modified example of the first embodiment, where (a) is a three-dimensional diagram of the short side, (b) is a front view of (a) viewed from the "D" side, (c) is a cross-sectional view of (a) cut along E-E' and viewed from the "F" side, and (d) is a cross-sectional view at each of positions (a), (b), and (c) in the vertical direction (Z-axis direction) of (c). [Figure 14]13A and 13B are diagrams showing the short side of a mold according to a fifth modified example of the first embodiment, where (a) is a three-dimensional diagram of the short side, (b) is a front view of (a) viewed from the "D" side, (c) is a cross-sectional view of (a) cut along E-E' and viewed from the "F" side, and (d) is a cross-sectional view at each of positions (a), (b), and (c) in the vertical direction (Z-axis direction) of (c). [Figure 15] 13A and 13B are diagrams showing the short side of a mold for a sixth variant of the first embodiment, where (a) is a three-dimensional diagram of the short side, (b) is a front view of (a) viewed from the "D" side, (c) is a cross-sectional view of (a) cut along E-E' and viewed from the "F" side, and (d) is a cross-sectional view at each of positions (a), (b), and (c) in the vertical direction (Z-axis direction) of (c). [Figure 16] FIG. 4 is a three-dimensional view showing a mold according to a second embodiment of the present invention. [Figure 17] FIG. 17 is an exploded perspective view of the mold shown in FIG. 16. [Figure 18] FIG. 11 is a three-dimensional view showing a mold according to a third embodiment of the present invention. [Figure 19] FIG. 11 is a three-dimensional view showing a short side portion of a mold according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, and can be embodied in various different forms. These embodiments are provided merely to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the invention. In order to explain the embodiments of the present invention, the drawings may be exaggerated, and the same reference numerals in the drawings indicate the same components.

[0016] FIG. 1 is a diagram showing a casting apparatus equipped with a mold according to an embodiment of the present invention. As shown in FIG. 1, the casting apparatus includes a tundish 20 that receives molten steel from a ladle 10 and stores it therein, a mold 3000 that receives the molten steel from the tundish 20 and initially solidifies it into a certain shape, and a nozzle 22 that supplies the molten steel from the tundish 20 to the mold 3000. The casting apparatus also includes a cooling section 40 that is disposed below the mold 3000 and sprays cooling water onto the unsolidified strand 1 pulled out of the mold 3000 to completely solidify it. Here, the cooling section 40 includes a plurality of segments 41. Each of the plurality of segments 41 may be a means including a plurality of rolls that can be rotated by the force that moves the strand 1, and nozzles positioned between the plurality of rolls that spray cooling water onto the strand 1.

[0017] Hereinafter, a mold according to a first embodiment of the present invention will be described with reference to FIGS. Fig. 2 is a three-dimensional view showing a mold according to a first embodiment of the present invention, and Fig. 3 is an exploded perspective view of the mold shown in Fig. 2. Fig. 4 is a cross-sectional view seen from the "A" side of Fig. 2 to explain the arrangement of a pair of short side portions. Fig. 5 is a cross-sectional view of the short side portion of Fig. 2 cut along B-B' and seen from the "A" side. Fig. 6 is a front view of the short side portion of Fig. 2 seen from the "C" side. Fig. 7 is a mold according to the first embodiment of the present invention, where (a) shows the upper part of the solidified shell and (b) shows the lower part of the solidified shell. Here, in order to provide a detailed explanation of the inner surface of the short side portion, FIG. 5 shows the short side portion standing vertically with respect to the ground.

[0018] 2 and 3, the mold 3000 has an internal space IS and is provided with a body 3100 having an inner surface if facing the internal space IS, a first inclined surface sf1 that is inclined so as to move away from the outer surface of as it progresses downward, and a second inclined surface sf2 that is provided below the first inclined surface sf1 and is inclined so as to move closer to the outer surface of as it progresses downward. The mold 3000 also has a protruding member 3122 that protrudes from the inner surface if of the body 3100 toward the internal space IS and is arranged so that the protruding length PL (see Figure 5) from the inner surface if of the body 3100 into the internal space IS decreases as it progresses downward.

[0019] As shown in Figures 2 and 3, the body 3100 comprises a pair of long side members (hereinafter referred to as the first and second long side members 3111), each of which extends in one direction (X-axis direction) and is spaced apart in a direction intersecting the extension direction (Y-axis direction), and a pair of short side members 3121 (hereinafter referred to as the first and second short side members 3121), each of which extends in a direction intersecting or perpendicular to the extension direction of the long side members 3111 (X-axis direction) and is spaced apart in the extension direction of the long side members 3111. A convex member 3122 is disposed on the inner surface if of such a body 3100, but as shown in Figures 2 and 3, the convex member 3122 may be disposed on the inner surface of the short side member 3121. Hereinafter, a configuration including the short side member 3121 and the convex member 3122 disposed on the short side member 3121 is defined as a short side portion 3120. In such a case, the mold 3000 can be described as including first and second long side members 3111 and first and second short side portions 3120 including the convex members 3122.

[0020] The first and second long side members 3111 and the first and second short side members 3121 are connected or joined to each other to provide a body 3100 having an internal space IS. For example, one end of each of the first and second short side members 3121 is connected to the inner side surface of the first long side member 3111, and the other end is connected to the inner side surface of the second long side member 3111, based on the Y axis direction. The first short side member 3121 and the second short side member 3121 are arranged side by side in the X axis direction and spaced apart from each other. At this time, the first short side member 3121 and the second short side member 3121 are arranged so that the separation distance between them is larger than the separation distance between the first long side member 3111 and the second long side member 3111. This provides a body 3100 in which the shape of the internal space IS is rectangular. More specifically, a body 3100 is provided having a rectangular internal space IS whose length in the X-axis direction is longer than its length in the Y-axis direction.

[0021] In the following, the extension direction of each of the long side member 3111 and the short side member 3121 is defined as the width direction. Therefore, the length of each of the long side member 3111 and the short side member 3121 in the extension direction can be defined as "width". Therefore, the width of the long side member 3111 is the length in the X-axis direction, and the width of the short side member 3121 is the length in the Y-axis direction. Note that the length of each of the long side member 3111 and the short side member 3121 in the horizontal direction intersecting with the width direction is defined as "thickness". Therefore, the thickness of the long side member 3111 is the length in the Y-axis direction, and the thickness of the short side member 3121 is the length in the X-axis direction.

[0022] When the first short side member 3121 and the second short side member 3121 are arranged to face each other, as shown in Figs. 2 and 4, the first and second short side members 3121 are inclined so that the separation distance SL between them decreases toward the lower side. More specifically, the first and second short side members 3121 are inclined so that the separation distance SL between at least the second inclined surface sf2 of the inner surfaces if of the first and second short side members 3121 decreases toward the lower side. Therefore, in the internal space IS of the mold 3000, the length in the long side direction decreases toward the lower side. In this way, the first and second short side members 3121 are arranged so that the separation distance SL between them decreases toward the lower side in order to compensate for the contraction of the solidified shell C in the long side direction. More specifically, this is to compensate for the shrinkage of a solidified shell (hereinafter, long side solidified shell LC) (see FIG. 7) formed by solidifying molten steel M along the first and second long side members 3111 in the extension direction of the first and second long side members 3111.

[0023] As shown in FIG. 6, each of the first and second short side members 3121 is provided so that its extension length, i.e., width SW, decreases as it moves downward. In other words, each of the first and second short side members 3121 is provided so that its extension length SW in the Y-axis direction, which is the short side direction of the mold 3000, decreases as it moves downward. For this reason, both side surfaces corresponding to one end and the other end of the first and second short side members 3121 are provided so as to be inclined with respect to the Y-axis direction. That is, the side surfaces of the first and second short side members 3121 are inclined so as to approach the center in the width direction as it moves downward. The first and second long side members 3111 are connected to the side surfaces of each of the first and second short side members 3121. Therefore, the first and second long side members 3111 are arranged so that the separation distance between them decreases as it moves downward.

[0024] In this manner, the side surface of the short side member 3121 is formed to be inclined, and the pair of long side members 3111 arranged to abut against the short side member 3121 are arranged to approach each other as they move downward, in order to compensate for the contraction of the solidified shell C in the short side direction. That is, this is to compensate for the contraction of the solidified shell (hereinafter, short side solidified shell SC) (see FIG. 7) formed by solidifying the molten steel M formed along the first and second short side members 3121 when the solidified shell contracts in the extension direction of the first and second short side members 3121. Hereinafter, the inner surface of the body in the mold according to the first embodiment of the present invention will be described with reference to Figs.

[0025] The inner side surface of the body 3100 is provided to include the first and second inclined surfaces sf1, sf2 as described above. In this case, of the long side member 3111 and the short side member 3121 constituting the body 3100, it is preferable that the inner side surface if of the short side member 3121 is provided to include the first and second inclined surfaces sf1, sf2 as shown in Figures 3 to 6. In this case, since the first and second short side members 3121 have the same shape, they will be described collectively as the short side member 3121.

[0026] The short side member 3121 is provided so that the inner side if facing the internal space of the mold 3000 includes an inclined surface. That is, the inner side if of the mold 3000 includes an inclined surface, and the inclined surface includes a first inclined surface sf1 inclined so as to move away from the outer side of as it progresses downward, and a second inclined surface sf2 provided below the first inclined surface sf1 and inclined so as to move closer to the outer side of as it progresses downward, as shown in FIG. 4 and FIG. 5. The inner side if may include an intermediate surface cf that is a surface positioned between the first inclined surface sf1 and the second inclined surface sf2. That is, the inner side if of the short side member 3121 includes the first inclined surface sf1, the intermediate surface cf, and the second inclined surface sf2, and the first inclined surface sf1, the intermediate surface cf, and the second inclined surface sf2 are formed in succession in this order. 4 and 5, the first inclined surface sf1, the middle surface cf, and the second inclined surface sf2 are provided to have different inclinations from one another. This can be explained as the inner surface if of the short side member 3121 having a multi-stage inclination, and more specifically, can be explained as having a three-stage inclination.

[0027] On the inner surface if of the short side member 3121, the connection point between the first inclined surface sf1 and the middle surface cf is the point where the inclination begins to change, and the connection point between the middle surface cf and the second inclined surface sf2 is the point where the inclination begins to change. Therefore, for ease of explanation, hereinafter, the point between the first inclined surface sf1 and the middle surface cf will be referred to as the first point P1, and the point between the middle surface cf and the second inclined surface sf2 will be referred to as the second point P2. Note that the upper end P of the short side member 3121 U From bottom P L The length up to the short side member 3121 is referred to as the height H1 of the short side member 3121.

[0028] The first inclined surface sf1 is an inclined surface formed on the upper part of the inner surface if of the body 3100, and is located at the uppermost end P U The first inclined surface sf1 extends downward from the outer surface of by a predetermined length. At this time, as described above, the first inclined surface sf1 is inclined so as to move away from the outer surface of as it moves downward. In other words, the first inclined surface sf1 is inclined so as to move closer to the center of the internal space IS of the mold 3000 as it moves downward. For this reason, the portion of the short side member 3121 where the first inclined surface sf1 is provided should preferably have a shape in which its thickness increases as it moves downward.

[0029] Referring to FIG. 5, the first inclined surface sf1 is located at the upper end P U At this time, the first inclined surface sf1 is extended from the upper end P U The slope may be constant from the first point P1 to the first point P2, i.e., may be constant without any change in slope or inflection point. The first point P1 is the upper end PU Therefore, the first inclined surface sf1 is located at a position spaced downward from the upper end P of the short-side member 3121 by a first distance S1. U It can be explained that the short-side member extends downward from the upper end P of the short-side member to a first point P1 that is spaced a first distance S1 from the upper end P of the short-side member. The first distance S1 is preferably 15% or more and 25% or less of the height H1 of the short-side member. U The first inclined surface sf1 can be described as a portion spaced downward from the upper end P of the short-side member 3121 by a length of 15% or more and 25% or less of the height H1 of the short-side member 3121. U and the first point P1 so that a first distance S1 between the first point P1 and the short-side member 3121 is 15% or more and 25% or less of the height H1 of the short-side member 3121.

[0030] The second inclined surface sf2 is an inclined surface formed on the lower part of the inner surface if of the body 3100, and is provided below the first inclined surface sf1. At this time, as described above, the second inclined surface sf2 is provided obliquely so as to approach the outer surface of as it progresses downward. Therefore, the portion of the short side member 3121 where the second inclined surface sf2 is provided has a shape in which its thickness becomes thinner as it progresses downward. As shown in FIG. 5, the second inclined surface sf2 extends from the second point P2, which is a position below the first point P1, to the lower end P L At this time, the second inclined surface sf2 extends from the second point P2 to the lower end P L Preferably, the gradient is constant up to the point where the gradient is 0.05 mm, i.e., the gradient is constant without any change in gradient or inflection points.

[0031] The second point P2 is the upper end P U The second inclined surface sf2 is a point spaced downward from the upper end P of the short-side member 3121 by a second distance S2 that is longer than the first distance S1. UA second distance S2 is provided downward from the second point P2 to the lower end P L It can be explained that the second distance S2 is extended to the upper end P of the short side member 3121. The second distance S2 is preferably more than 40% and less than 50% of the height H1 of the short side member 3121. U A second distance S2, which is more than 40% and less than 50% of the height H1 of the short-side member 3121, is spaced downward from the second point P2 to the lower end P L It will be extended to.

[0032] The intermediate surface cf is a surface provided between the first inclined surface sf1 and the second inclined surface sf2, and is provided at an equal distance from the outer surface of in the vertical direction. For this reason, the portion of the short side member 3121 where the intermediate surface cf is provided should preferably have a shape whose thickness does not change in the vertical direction or a shape whose thickness is constant. The intermediate surface cf extends from the first point P1 to the second point P2. In other words, the intermediate surface cf extends from the upper end P U The intermediate surface cf extends downward from a point (first point P1) spaced apart by a first distance S1 to a point (second point P2) spaced apart by a second distance S2 from the short side member 3121. Such an intermediate surface cf may be provided so as not to be inclined, that is, so as to be perpendicular to the ground, when the short side member 3121 is placed perpendicular to the ground as shown in FIG.

[0033] As described above, the first inclined surface sf1, which is the inner surface of the upper part of the short side member 3121, is inclined so as to move away from the outer surface of as it moves downward. This is to further compensate for the shrinkage of the solidified shell C in the long side direction in the upper part of the mold 3000 where solidification shrinkage occurs relatively severely. That is, when the first and second short side members 3121 are arranged opposite each other, as described above, the solidification shrinkage in the long side direction can be compensated by inclining the first inclined surface sf1 so that the separation distance between them becomes closer as it moves downward. Here, by providing the first inclined surface sf1 on the inner surface if of the short side member 3121, the solidification shrinkage in the long side direction can be further compensated. This is because the reduction rate of the length of the internal space IS in the long side direction of the mold 3000 decreases as it moves downward, and the reduction rate caused by the first inclined surface sf1 is further added to the reduction rate caused by inclining the short side member 3121.

[0034] Therefore, when the short side member 3121 is provided with the first inclined surface sf1, the rate of decrease in the length of the long side direction (X-axis direction) of the internal space of the mold 3000 decreases toward the lower side is larger than when the inclined surface sf1 is not provided. Therefore, when the short side member 3121 is provided with the first inclined surface sf1, the compensation rate of solidification shrinkage in the long side direction of the mold 3000 is further improved than when the inclined surface sf1 is not provided. In particular, the compensation rate is improved in the upper part of the mold 3000 where solidification shrinkage occurs significantly. This makes it possible to suppress or prevent the generation of a gap between the long side solidified shell LC (see FIG. 7) and the short side member 3121, and to suppress or prevent the occurrence of surface cracks and breakouts due to the shrinkage of the solidified shell LC.

[0035] The second inclined surface sf2 is inclined so as to approach the outer surface of as it advances downward. This is to suppress friction between the slab 1 formed by solidifying molten steel in the lower part of the mold 3000 and the inner surface of the short side member 3121. That is, in order to compensate for solidification shrinkage in the long side direction, the first and second short side members 3121 are inclined so that the distance between them decreases as they advance downward. Therefore, in the lower part of the mold 3000, the distance between the first short side member 3121 and the second short side member 3121 becomes significantly smaller, but there is a risk that friction will occur between the slab 1 and the short side member 3121 when the slab 1 is withdrawn to the lower side of the mold 3000. However, by forming the second inclined surface sf2 on the short side member 3121, friction between the slab 1 and the short side member 3121 can be suppressed or prevented.

[0036] 4 and 5, when the second inclined surface sf2 is provided so as to approach the outer surface as it progresses downward, the distance from the center of the internal space IS of the mold 3000 can be made larger than when sf2 is provided vertically, thereby reducing the adhesion force between the slab 1 and the short side member 3121. Furthermore, by reducing friction between the slab 1 and the short side member 3121, wear of the short side member 3121 can be reduced, and as a result, the life of the short side member 3121, i.e., the mold 3000, can be extended.

[0037] On the other hand, in the internal space IS of the mold 3000, the amount of shrinkage of the solidified shell is greatest at the upper part and decreases toward the lower part. The position where the intermediate surface cf is provided is the center part of the mold 3000, where the amount of shrinkage is smaller than that at the upper part, but larger than that at the lower part. For this reason, it is necessary to compensate for the amount of shrinkage at the center part. However, when the second inclined surface sf2 is formed continuously from the first point P1 without the intermediate surface cf, the rate of decrease in the length in the long side direction may become smaller as the length decreases downward in the center of the internal space of the mold 3000. For this reason, there is a concern that solidification shrinkage in the center of the internal space IS of the mold 3000 may not be sufficiently compensated for.

[0038] Furthermore, when the first inclined surface sf1 is extended to the second point P2, there is a risk of a problem in that excessive compensation is provided compared to the amount of shrinkage of the solidified shell in the center of the internal space IS of the mold 3000. Therefore, it is preferable to provide an intermediate surface cf between the first inclined surface sf1 and the second inclined surface sf2, where the distance from the outer surface of does not change in the vertical direction, or where the gradient does not change. The protruding member 3122 is disposed on the inner surface if of the body 3100. That is, the protruding member 3122 protrudes from the inner surface if of the body 3100 toward the internal space IS. In this case, it is preferable that the protruding member 3122 is disposed on the inner surface if of the short side member 3121, as shown in Figs. 2, 3 and 6.

[0039] Hereinafter, the short side portion including the short side member and the protruding member will be described with reference to Figs. FIG. 8 is a diagram relating to the first embodiment of the present invention, in which (a) is a three-dimensional view of the short side portion, (b) is a front view of (a) viewed from the "D" side, (c) is a cross-sectional view of (a) cut along E-E' and viewed from the "F" side, and (d) is a cross-sectional view at each position (a), (b), and (c) in the vertical direction (Z-axis direction) of (c).

[0040] Figure 9 is a diagram for explaining the extension length of the inner surface of the short side portion in the short side portion according to the first embodiment of the present invention, where (a) is a diagram in which a curve is formed by a convex member arranged on the inner surface of the short member, and (b) is a diagram in which the inner surface of the short member is a straight line. 2, 3 and 8(a), a protruding member 3122 is disposed on the inner surface if of the short-side member 3121. That is, the protruding member 3122 protrudes from the inner surface if of the short-side member 3121 toward the internal space IS of the mold 3000.

[0041] The protruding member 3122 extends in the extension direction of the short side member 3121, that is, in the width direction (Y-axis direction). In this case, the protruding member 3122 has a shape in which the protruding length PL increases from both ends in the extension direction toward the center. In other words, the protruding member 3122 has a shape in which the protruding length PL decreases from the center in the width direction toward both ends. For this reason, it is preferable that the position at which the protruding member 3122 has the maximum protruding length PL in the width direction is the center of the protruding member 3122 in the width direction. In this case, it is preferable that the protruding member 3122 is provided so that its center in the width direction coincides with the center of the short side member 3121 in the width direction. Furthermore, it is preferable that the protruding members 3122 are provided with a constant protruding length PL in the width direction or with the same shape.

[0042] The width PW of the convex member 3122 is set smaller than the width SW of the short side member 3121, as shown in Figures 8(a) and (b). Therefore, as shown in Figure 8(b), the inner surface if of the short side member 3121 is present on the outer side of the convex member 3122 in the width direction. Note that the width PW of the convex member 3122 is set constant in the up-down direction, as shown in Figures 8(b) and (d). Therefore, as shown in Figure 8(b), the line connecting the uppermost end and the lowermost end of the convex member 3122 (hereinafter, the boundary line DL) may be a straight line without a bending rate. The protruding member 3122 is a top end P of the inner surface if of the short side member 3121. U8(c) and 8(d), the protruding member 3122 is formed so that the protruding length PL decreases as it goes downward. That is, the protruding length PL of the protruding member 3122 is shorter at the lower part than at the upper part. Note that, as shown in FIG. 8(c), the protruding member 3122 is preferably provided so that the protruding length PL of the protruding member 3122 decreases as it goes downward, and the decreasing gradient is constant.

[0043] The extension length of the protruding member 3122 in the vertical direction is shorter than the height H1 of the short side member 3121. U At this time, the upper end P U The distance between the upper end P1 of the short-side member 3121 and the third point P3 (hereinafter, the third distance S3) is longer than the first distance S1 and shorter than the second distance S2. More specifically, the third distance S3 may be 30% or more and 40% or less of the height H1 of the short-side member 3121. Therefore, the third point P3 is located at the upper end P1 of the short-side member 3121. U It can be explained that the location is spaced downward from the upper end P of the short side member 3121 by a length of 30% or more and 40% or less of the height H1 of the short side member 3121. U The protruding member 3122 is extended so that a separation distance S3 between the protruding member 3122 and the third point P3 is 30% or more and 40% or less of the height H1 of the short-side member 3121.

[0044] In this way, the convex member 3122 is formed on the inner surface if of the short side member 3121 so as to protrude or be convex toward the internal space of the mold 3000, so that the extension length of the inner surface of the short side portion 3120 becomes longer than in the past. Here, the inner surface of the short side portion 3120 refers to a surface including the other side surface that is the opposite side of one side surface of the convex member 3122 connected to the short side member 3121 and the inner surface if of the short side member 3121 positioned outside the convex member 3122 in the width direction. Note that the extension length SIL of the inner surface if of the short side portion 3120 means the length of the path from one end E1, which is one of both ends of the inner surface of the short side portion 3120 in the Y-axis direction, to the other end E2, as shown in FIG. 9(a).

[0045] The inner surface of the short side portion 3120 is not a straight line but a curved line bent at least once because of the convex member 3122. The length of the path from one end of the curve to the other end (see FIG. 9(a)) is longer than the path from one end of the straight line to the other end (see FIG. 9(b)). Therefore, the longer the protruding length PL of the convex member 3122, the longer the path from one end E1 of the inner surface to the other end E2 of the short side portion 3120, so the extension length SIL of the inner surface of the short side portion 3120 increases. The protruding length PL of the convex member 3122 decreases as it progresses downward. Therefore, the extension length of the inner surface of the short side portion 3120 decreases as it progresses downward.

[0046] On the other hand, the short side member 3121 is provided so that its width decreases as it advances downward. Therefore, the length of the short side direction of the internal space of the mold 3000 decreases as it advances downward. In this case, when the convex member 3122 is provided on the short side member 3121, the rate of decrease of the length of the short side direction of the internal space IS of the mold 3000 as it advances downward becomes larger than when the convex member is not provided. This is because, in the rate of decrease of the length of the short side direction of the internal space IS of the mold 3000 as it advances downward, the rate of decrease caused by decreasing the width of the short side member 3121 is added to the rate of decrease caused by the convex member 3122 provided so that the protruding length PL decreases as it advances downward.

[0047] Therefore, the mold 3000 can further compensate for solidification shrinkage in the short side direction by using the convex member 3122. That is, by disposing the convex member 3122 on the short side member 3121, solidification shrinkage in the short side direction can be further compensated for. Therefore, the compensation rate of solidification shrinkage in the short side direction of the mold 3000 is improved. This can suppress or prevent the generation of a gap between the short side solidified shell SC and the long side member 3111, and suppress or prevent the occurrence of surface cracks and breakouts due to shrinkage of the solidified shell.

[0048] Figures 10 and 11 are diagrams showing short sides of a mold according to a first and second modified example of the first embodiment, respectively. Figure 12 is a diagram showing short sides of a mold according to a third modified example of the first embodiment. In the above first embodiment, it has been described that the first inclined surface sf1 is formed to have a constant gradient, i.e., a constant inclination, up to the first point P1. However, the present invention is not limited to this, and the first inclined surface sf1 may be provided to have a multi-stage gradient, as in the first modified example shown in FIG. 10. That is, the first inclined surface sf1 is inclined so as to get further away from the outer surface of as it progresses downward, but it is preferable that the gradient is formed so that it changes at least once. In other words, the first inclined surface sf1 extends from the upper end P of the short side member 3121 to the upper end P of the short side member 3121.U It is preferable that the slope is changed with respect to a point (first inflection point IP1) between the upper end P1 and the first point P1 as a reference. In this case, the slope is set so that the slope of the lower region is smaller than the slope of the upper region with respect to the first inflection point IP1 as a reference. In this way, U When one first inflection point IP1 is provided between the first point P1 and the first location P1, the first inclined surface sf1 can be described as being provided to have a two-stage inclination. The first inclined surface sf1 is not limited to being provided to have a two-stage inclination, and may be provided to have a three or more stage inclination. For this reason, two or more first inflection points IP1 may be provided.

[0049] Also, in the above first embodiment, it has been described that the second inclined surface sf2 is formed to have a constant gradient or a constant inclination from the second point P2 to the lower end P of the short side member 3121. However, the present invention is not limited to this, and the second inclined surface sf2 may be provided to have a multi-stage gradient, as in the second modified example shown in FIG. 11. That is, the second inclined surface sf2 is inclined so as to approach the outer surface of as it progresses downward, but it is preferable that the gradient is formed so that it changes at least once. In other words, the second inclined surface sf2 is formed to have a constant gradient or a constant inclination from the second point P2 to the lower end P of the short side member 3121. L The gradient changes with respect to a point (second inflection point IP2) between the second inflection point IP2 and the lower end P of the short side member 3121. At this time, the gradient of the lower region is set to be larger than the gradient of the upper region with respect to the second inflection point IP2. L When one second inflection point IP2 is provided between the first inflection point IP2 and the second inclined surface sf2, the second inclined surface sf2 has a two-stage inclination. The second inclined surface sf2 is not limited to having a two-stage inclination, and may have three or more stages of inclination. For this reason, two or more second inflection points IP2 may be provided.

[0050] Furthermore, in the first embodiment, the protruding member 3122 is located at the upper end P U It has been described above that the protruding length PL decreases at a constant rate from the upper end P U to the third point P3 so as to have a constant inclination. However, the present invention is not limited to this at all, and the protruding member 3122 may be provided so as to have a multi-stage incline, as in the third modified example shown in Fig. 12. That is, the protruding member 3122 is formed so that its protruding length PL decreases as it progresses downward, but may be formed so that the degree of decrease changes at least once or more. In other words, the protruding member 3122 may be formed so that its gradient changes at least once or more as it extends from the upper end of the short side member 3121 to the third point P3. That is, the protruding member 3122 may be formed so that its protruding length PL decreases as it progresses downward, but may be formed so that the degree of decrease changes at least once or more. In other words, the protruding member 3122 may be formed so that its gradient changes at least once or more as it extends from the upper end P3 of the short side member 3121 to the third point P3. U and the third point P3 as a reference point (third inflection point IP3). It is preferable that the gradient of the lower region is greater than the gradient of the upper region with respect to the third inflection point IP3 as a reference point.

[0051] The third inflection point IP3 may be, for example, the same as the first point P1 as shown in FIG. U and the third location P3. In this way, the third point P3 and the lower end P L When one third inflection point IP3 is provided between the first and second inflection points IP1 and IP2, the convex member 3122 has two inclination steps in the up-down direction. Needless to say, the convex member 3122 is not limited to having a two-step inclination, and may have three or more inclination steps. For this reason, two or more third inflection points IP3 may be provided.

[0052] Figures 13 to 15 are diagrams showing the short side portions of molds according to fourth to sixth modified examples of the first embodiment, where (a) to (d) of Figures 13 to 15 are the same as those explained in (a) to (d) of Figure 8. In the first embodiment and the first to third modified examples described above, the width PW of the convex member 3122 is constant in the vertical direction. However, the present invention is not limited to this, and the width PW of the convex member 3122 may decrease downward, as in the fourth to sixth modified examples shown in Fig. 13 to Fig. 15. That is, the convex member 3122 may have a shape in which its protruding length PL decreases downward, and at the same time, its width PW also decreases downward.

[0053] In this way, when the width PW of the convex member 3122 decreases toward the lower side, the rate of decrease may be constant as shown in Fig. 13. Therefore, as shown in Fig. 13, the line connecting the uppermost end and the lowermost end of the convex member, i.e., the boundary line DL, may be a straight line without a bending rate. However, the present invention is not limited thereto, and the boundary line DL may be provided to have a bending rate, as in the fifth and sixth modified examples shown in Figs. 14 and 15. In this case, as in the fifth modified example shown in Fig. 14, the boundary line DL may be a shape that is convex toward the outside of the convex member 3122, or a shape that has a positive bending rate. Also, as in the sixth modified example shown in Fig. 15, the convex member may have a shape in which the boundary line DL is concave toward the inside of the convex member 3122, or a shape that has a negative bending rate. In this way, the boundary line DL being provided to have a positive bending rate or a negative bending rate means that the rate of decrease of the width PW of the convex member 3122 as it decreases toward the lower side is not constant.

[0054] FIG. 16 is a three-dimensional view showing a mold according to a second embodiment of the present invention, and FIG. 17 is an exploded perspective view of the mold shown in FIG. In the above-mentioned first embodiment, the inner surface if of the short side member 3121 includes the first and second inclined surfaces sf1, sf2 and the intermediate surface cf, and the convex member 3122 is disposed on the short side member 3121. However, the present invention is not limited to this configuration, and as in the second embodiment shown in Figs. 16 and 17, the inner surface if of the long side member 3111 may include the first and second inclined surfaces sf1, sf2 and the intermediate surface cf, and the convex member 3112 may be disposed on the long side member 3111. In this case, the components including the long side member 3111 and the convex member 3112 disposed on the long side member 3111 may be defined as the long side portion 3110. In such a case, the mold 3000 can be described as having the first and second long side portions 3110 including the convex member 3112, and the first and second short side portions 3120 including the convex member 3122. The first embodiment and the first and second modified examples are applicable to the first and second inclined surfaces sf1, sf2 of the long side member 3111. The first embodiment and the third to sixth modified examples are applicable to the protruding member 3112 disposed on the long side member 3111.

[0055] Fig. 18 is a three-dimensional view showing a mold according to a third embodiment of the present invention, Fig. 19 is a three-dimensional view showing a short side portion of a mold according to the third embodiment of the present invention. A mold according to a third embodiment of the present invention will be described below with reference to Figures 18 and 19. In this case, the contents that overlap with the above-mentioned embodiments will be omitted or simplified.

[0056] The mold 3000 according to the third embodiment may be a chamfered mold (CHAMFERED MOLD). That is, the mold 3000 includes a body 3100 having first and second inclined surfaces sf1, sf2 and an intermediate surface cf on an inner surface if and a protruding member 3123 at a corner, and a convex member 3122 that protrudes from the inner surface if of the body 3100 toward the internal space IS and is provided so that the protruding length from the inner surface if of the body 3100 into the internal space IS decreases as it progresses downward. In this case, the first and second inclined surfaces sf1, sf2 and the intermediate surface cf may be provided on the inner surface if of the short side member 3121. A convex member 3122 may be disposed on the inner surface if of the short side member 3121. Here, the first embodiment and the first and second modified examples are applicable to the first and second inclined surfaces sf1, sf2, and the first embodiment and the third to sixth modified examples are applicable to the convex member 3122.

[0057] The protruding members 3123 protrude from the inner surface if of the body 3100 toward the internal space, but may also protrude from the inner surface if of the short side member 3121 as shown in Fig. 18 and Fig. 19. In this case, the protruding members 3123 are provided so as to be positioned on both peripheral edges in the extension direction of the short side member 3121. That is, based on the Y-axis direction, the protruding members 3123 protrude from the inner surfaces if of both peripheral edges of the short side member 3121 toward the internal space IS of the mold 3000. The protruding members 3123 are configured to create a chamfered shape in the mold 3000, and can be referred to as chamfered-shaped protruding members 3123. In such a chamfered mold, a protruding member 3112 may also be attached to the long side portion 3110.

[0058] In the above embodiment, the mold 3000 is described as being composed of a long side member 3111 and a short side member having different lengths, and has a generally rectangular shape. However, the present invention is not limited to this, and the mold 3000 may have a square shape.

[0059] According to the mold 3000 according to the embodiment of the present invention, the compensation rate for shrinkage of the solidified shell C is improved. That is, the inclined surface and the convex member provided on the inner surface if of the body 3100 improve the compensation rates for shrinkage of the solidified shell in both the long side direction and the short side direction. In particular, the compensation rate for shrinkage of the solidified shell in the upper part of the internal space IS of the mold 3000 is improved. Therefore, it is possible to suppress or prevent the generation of a gap between the inner surface of the mold 3000 and the solidified shell due to the shrinkage of the solidified shell, and it is possible to suppress or prevent the phenomenon of delayed solidification caused by this. Therefore, it is possible to suppress or prevent the occurrence of defects on the surface of the slab and the occurrence of breakouts. In addition, the inclined surface provided on the inner surface if of the mold 3000 can reduce friction between the inner surface if of the mold 3000 and the cast piece, thereby extending the life of the mold 3000. [Industrial Applicability]

[0060] According to an embodiment of the present invention, the compensation rate for shrinkage of the solidified shell is improved. That is, the inclined surface and the convex member provided on the inner surface of the body improve the compensation rate for shrinkage of the solidified shell in the long side direction and the short side direction. In particular, the compensation rate for shrinkage of the solidified shell in the upper part of the internal space of the mold is improved. Therefore, it is possible to suppress or prevent a gap from being generated between the inner surface of the mold and the solidified shell due to the shrinkage of the solidified shell, and it is possible to suppress or prevent the phenomenon of delayed solidification caused by this. As a result, it is possible to suppress or prevent the occurrence of defects on the surface of the cast slab and the occurrence of breakouts. [Explanation of symbols]

[0061] 1: Cast piece 10: Ladle 20: Tundish 22: Nozzle 40: Cooling section 41: Segment 3000: Mold 3100: Body 3110: Long side 3111: Long side member 3112: Protruding member (arranged on long side member) 3120: Short side 3121: Short side member 3122: Convex member (arranged on short side member) 3123: Protruding member C: Solidified shell cf: intermediate plane DL:Boundary line E1: One end in the Y-axis direction of the inner surface of the short side portion 3120 E2: The other end in the Y-axis direction of the inner surface of the short side portion 3120 H1: Body height if:Inner surface IP1: The first inflection point IP2: The second inflection point IP3: The third inflection point IS: interior space LC: Long side solidified shell M: Molten steel оf:Outside surface P1: First place P2: Second place P3: The third part PL: Projection length P L : Bottom edge of the inside of the body P U :Top edge of the inside of the body PW: Width (of convex part) S1: First distance S2: Second distance S3: The third distance SC: Short side solidified shell sf1: first inclined surface sf2: second inclined surface SIL: Extension length (length from one end E1 of the short side to the other end E2) SL:Separation distance SW: Width, extension length in the Y-axis direction

Claims

1. A mold having an internal space into which molten steel can be poured, a body having the internal space; a protruding member that protrudes from an inner surface of the body toward the internal space and whose protruding length from the inner surface into the internal space decreases toward a lower side, The inner surface of the body facing the internal space includes a first inclined surface inclined downward so as to move away from an outer surface opposite to the inner surface, and a second inclined surface provided below the first inclined surface and inclined downward so as to approach the outer surface, The first inclined surface is an upper end (P Ｕ ) to a first distance (S １ A first point (P １ ) and The second inclined surface is １ ) and the upper end (P Ｕ ) to a second distance (S ２ A second location (P ２ ) to the lower end (P Ｌ ) and The first distance (S １ ) and the second distance (S ２ ) is the height (H １ ) is even shorter than The width of the protruding member is shorter than the width of the body, The protruding member is disposed at the upper end (P Ｕ ) to a third distance (S ３ A third location (P ３ ) and The third distance (S ３ ) is the first distance (S １ ) and is longer than a second distance (S ２ ) is a template that is even shorter than the

2. The first distance (S １ ) is the height (H １ 2. The mold according to claim 1, characterized in that the mould has a mould content of 15% or more and 25% or less of the mould content of 15% or more.

3. The first inclined surface is an upper end (P Ｕ ) and the first portion (P １ ) the first inflection point (IP １ ) The slope of the slope changes based on the In the first inclined surface, the first inflection point (IP １ The angle between the lower region of the first inflection point (IP １ 2. The mold of claim 1, wherein the angle between the upper region of the mold and the outer surface is smaller than the angle between the upper region of the mold and the outer surface.

4. The first inflection point (IP １ A plurality of first inflection points (IP １ ) is the upper end (P Ｕ ) and the first portion (P １ 4. The mold according to claim 3, characterized in that the first and second electrodes are provided at different positions between the first and second electrodes.

5. The second distance (S ２ ) is the height (H １ 2. The mold according to claim 1, characterized in that the mould has a mould content of 40% or more and 50% or less of the mould content.

6. The second inclined surface is ２ ) and the lower end of the inner surface of the body (P Ｌ ) The second inflection point (IP ２ ) The slope of the slope changes based on the In the second inclined surface, the second inflection point (IP ２ The angle between the lower region of the second inflection point (IP ２ 2. The mold of claim 1, wherein the angle between the upper region of the mold and the outer surface is greater than the angle between the upper region of the mold and the outer surface.

7. The second inflection point (IP ２ ) is provided in a plurality of second inflection points (IP ２ ) is the second part (P ２ ) and the lower end of the inner surface of the body (P Ｌ 7. The mold according to claim 6, characterized in that the first and second electrodes are provided at different positions between the first and second electrodes.

8. 2. The mold according to claim 1, wherein an intermediate surface is provided between the first inclined surface and the second inclined surface, the intermediate surface being equidistant from the outer surface in the vertical direction.

9. The body includes: A pair of long side members each extending in one direction and arranged opposite each other in a direction intersecting the extending direction; a pair of short side members each extending to intersect with the long side members and disposed opposite each other to seal the gap between the pair of long side members; 2. The mold according to claim 1, wherein the first and second inclined surfaces are provided on an inner surface of at least one of the short side member and the long side member.

10. The pair of short side members are inclined so that the distance between them decreases toward the bottom, 10. The mold according to claim 9, wherein the side surface of the short side member that abuts against the long side member is inclined downwardly toward the center in the width direction of the short side member.

11. 10. The mold according to claim 9, wherein the body has protruding members protruding toward the internal space at both ends of the short side members in the extension direction so as to form chamfered surfaces at corners of a cast piece to be cast.

12. 10. The mold according to claim 9, wherein the protruding member is provided to protrude from an inner surface of either one of the long side member and the short side member toward the internal space.

13. The gradient of the protruding length of the protruding member decreasing as it advances downward is the gradient of the protruding length of the protruding member decreasing as it advances downward from the upper end (P Ｕ ) and the third portion (P ３ ) the third inflection point (IP ３ ) the gradient changes based on In the convex member, the third inflection point (IP ３ The angle between the lower region of the third inflection point (IP ３ 2. The mold according to claim 1, wherein the angle between the upper region of the mold and the outer surface is greater than the angle between the upper region of the mold and the outer surface.

14. The third inflection point (IP ３ ) is provided in a plurality of third inflection points (IP ３ ) is the upper end (P Ｕ ) and the third portion (P ３ 14. The mold according to claim 13, characterized in that the first and second electrodes are provided at different positions between the first and second electrodes.

Images