JP7634662B2 - template - Google Patents

Description

The present invention relates to a mold, and more specifically to a mold that can suppress or prevent the occurrence of defects in the cast piece and damage to the mold.

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 in 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 significantly shrinks. If such shrinkage of the solidified shell cannot be compensated for in the mold, an air layer or a gap occurs between the mold and the solidified shell. When a gap occurs, the heat transfer ability between the mold and the solidified shell or the molten steel decreases, causing a phenomenon of delayed solidification, which causes breakout and defects in the cast slab.

In order to solve this problem, a mold has been designed to have a slope 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.

Korean Patent Publication No. 10-2000-0008003

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.

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 downward so as to move away from the outer surface, which is the opposite surface of the inner surface, and a second inclined surface that is provided below the first inclined surface and is inclined downward so as to move closer to the outer surface.

The first inclined surface extends to a first point P1 spaced apart from an upper end P _U of the inner surface of the body by a distance corresponding to a first distance _S1 , and the second inclined surface extends from a second point _P2 , which is a location below the first point _P1 and spaced apart from the upper end P _U of the inner surface of the body by a distance corresponding to a second distance _S2 , to _{a lower end P L of} the inner surface of the body, and 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 is preferably 15% or more and 25% or less of the height _H1 of the body.

The first inclined surface has a shape whose inclination gradient changes with respect to a first inflection point _IP1 between an upper end _PU of the inner surface of the body and the first point _P1 , and it is preferable that, in the first inclined surface, an angle formed between a lower region of the first inflection point _IP1 and the outer surface is smaller than an angle formed between an upper region of the first inflection point _IP1 and the outer surface.
The first inflection point _IP1 may be provided in a plurality of positions, and the plurality of first inflection points _IP1 may be provided at different positions between an upper end _PU of the inner surface of the body and the first point _P1 .
The second distance _S2 is preferably 40% or more and 50% or less of the height _H1 of the body.

The second inclined surface has a shape whose inclination gradient changes with respect to a second inflection point _IP2 between the second location _P2 and a lower end _PL of the inner surface of the body, and it is preferable that, in the second inclined surface, an angle formed between a lower region of the second inflection point _IP2 and the outer surface is larger than an angle formed between an upper region of the second inflection point _IP2 and the outer surface.
The second inflection points _IP2 may be provided in a plurality of locations, and the plurality of second inflection points _IP2 may be provided at different positions between the second point _P2 and a lower end _PL of the inner surface of the body.
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.

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.

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 convex member extends from an upper end _PU of the inner surface of the body to a third point _P3 spaced apart by a third distance _S3 , and the third distance _S3 is preferably longer than the first distance _S1 and shorter than the second distance _S2 .

It is preferable that the gradient of the decrease in the protruding length as the convex member progresses downward changes with respect to a third inflection point _IP3 between the upper end _PU of the body and the third point _P3 , and that the angle between the region below the third inflection point _IP3 and the outer surface of the convex member is larger than the angle between the region above the third inflection point _IP3 and the outer surface.
It is preferable that a plurality of the third inflection points _IP3 are provided, and the plurality of the third inflection points _IP3 are provided at different positions between the upper end _PU of the inner surface of the body and the third point _P3 .

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.

FIG. 1 is a diagram showing a casting apparatus including a mold according to an embodiment of the present invention. FIG. 1 is a three-dimensional view showing a mold according to a first embodiment of the present invention. FIG. 3 is an exploded perspective view of the mold shown in FIG. 2 . 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. This is a cross-sectional view of the short side of Figure 2 cut along B-B' and viewed from the "A" side. FIG. 3 is a front view of the short side portion of FIG. 2 as viewed from the "C" side. 1A and 1B are views showing a mold according to a first embodiment of the present invention, in which FIG. 1A shows an upper part of a solidified shell, and FIG. 1B shows a lower part of the solidified shell. 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 a 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 of positions (a), (b), and (c) in the vertical direction (Z-axis direction) of (c). 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, in which (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. FIG. 11 is a diagram showing a short side portion of a mold according to a first modified example of the first embodiment. FIG. 13 is a diagram showing a short side portion of a mold according to a second modified example of the first embodiment. FIG. 13 is a diagram showing a short side portion of a mold according to a third modified example of the first embodiment. 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). 13A and 13B are diagrams showing the short side of a mold for 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). 11A and 11B are diagrams showing the short side of a mold for a sixth 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). FIG. 4 is a three-dimensional view showing a mold according to a second embodiment of the present invention. FIG. 17 is an exploded perspective view of the mold shown in FIG. 16. FIG. 11 is a three-dimensional view showing a mold according to a third embodiment of the present invention. FIG. 11 is a three-dimensional view showing a short side portion of a mold according to a third embodiment of the present invention.

Hereinafter, the embodiments of the present invention will be described in more detail with reference to the attached 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 convey the scope of the invention to those skilled in the art. 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.

FIG. 1 is a diagram showing a casting apparatus including 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 predetermined 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 with which the strand 1 moves, and nozzles positioned between the plurality of rolls that spray cooling water onto the strand 1.

A mold according to a first embodiment of the present invention will be described below 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.

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 inclined so as to move away from the outer surface 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 surface of as it progresses downward.
The mold 3000 also includes a convex 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 to the internal space IS decreases as it progresses downward.

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 installed at a distance 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 member 3122.

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 of the first long side member 3111, and the other end is connected to the inner side 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. 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 greater than the separation distance between the first long side member 3111 and the second long side member 3111. As a result, a body 3100 having an internal space IS in a square shape is provided. More specifically, a body 3100 is provided that has a rectangular internal space IS whose length in the X-axis direction is longer than its length in the Y-axis direction.

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 that intersects 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.

When the first short side member 3121 and the second short side member 3121 are arranged to face each other, as shown in Fig. 2 and Fig. 4, the first and second short side members 3121 are inclined so that the separation distance SL decreases as they move downward. 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 as they move downward. Therefore, in the internal space IS of the mold 3000, the length in the long side direction decreases as they move downward. In this way, the first and second short side members 3121 are arranged so that the separation distance SL between them decreases as they move downward 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 Figure 7) formed by solidifying molten steel M along the first and second long side members 3111 when the solidified shell shrinks in the extension direction of the first and second long side members 3111.

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. In other words, 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 they move 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 they move downward.

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.
The inner surface of the body in the mold according to the first embodiment of the present invention will be described below with reference to Figs.

The inner side 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 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.

The short side member 3121 is provided so that the inner side surface if facing the internal space of the mold 3000 includes an inclined surface. That is, the inner side surface if of the mold 3000 includes an inclined surface, and the inclined surface includes a first inclined surface sf ₁ inclined so as to move away from the outer side surface of as it progresses downward, and a second inclined surface sf 2 provided below the first inclined surface sf ₁ and inclined so as to move closer to the outer side surface of as it progresses downward, as shown in Figures 4 and _5. Note that the inner side surface if may include an intermediate surface cf, which is a surface positioned between the first inclined surface sf ₁ and the second inclined surface sf _2. That is, the inner side surface if of the short side member 3121 includes the first inclined surface sf ₁ , the intermediate surface cf, and the second inclined surface sf ₂ , and the first inclined surface sf ₁ , the intermediate surface cf, and the second inclined surface sf ₂ 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 each other. This can be explained as the inner surface if of the short side member 3121 having multiple inclinations, and more specifically, can be explained as having three inclinations.

Among the inner surfaces 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 starts to change, and the connection point between the middle surface cf and the second inclined surface _sf2 is the point where the inclination starts to change. Therefore, for ease of explanation, the point between the first inclined surface _sf1 and the middle surface cf is referred to as the first point _P1 , and the point between the middle surface cf and the second inclined surface _sf2 is referred to as the second point _P2 below. The length from the upper end P _U to the lower end P _L of the short side member 3121 is referred to as the height _H1 of the short side member 3121.

The first inclined surface _sf1 is an inclined surface formed on the upper part of the inner surface if of the body 3100, and extends downward by a predetermined length from the uppermost end _PU of the inner surface if of the short side member 3121. At this time, the first inclined surface _sf1 is inclined so as to move away from the outer surface of as it progresses downward, as described above. 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 progresses downward. For this reason, the portion of the short side member 3121 where the first inclined surface _sf1 is provided may have a shape in which its thickness increases as it progresses downward.

5, the first inclined surface _sf1 extends from the upper end P _U of the short side member 3121 to the first point P _1. In this case, the first inclined surface _sf1 may be provided so as to have a constant gradient from the upper end P _U of the short side member 3121 to the first point P _1. In other words, it is preferable to provide the first inclined surface sf1 with a constant gradient without any gradient change or inflection point.
The first point _P1 can be explained as a point spaced downward from the upper end P _U of the short side member 3121 by the first distance _S1 . Therefore, the first inclined surface _sf1 can be explained as extending downward from the upper end P _U of the short side member 3121 to the first point _P1 spaced downward by the first distance _S1 . The first distance _S1 is preferably 15% or more and 25% or less of the height _H1 of the short side member. Therefore, the first point _P1 can be explained as a point spaced downward from the upper end P _U of the short side member by a length of 15% or more and 25% or less of the height _H1 of the short side member 3121. For this reason, the first inclined surface sf1 is _extended so that the first distance _S1 between the upper end P _U of the _short side member 3121 and the first point P1 is greater than or equal to 15% and less than or equal to 25% of the height _H1 of the short side member 3121.

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.
5, the second inclined surface _sf2 extends from a second point P2, which is a position below the first point _{P1 ,} to the lower end P _L of the short side member 3121. In this case, the second inclined surface _sf2 is preferably provided so as to have a constant gradient from the second point _P2 to the lower end P _L of the short side member 3121. In other words, it is preferably provided with a constant gradient without any change in gradient or inflection point.

The second point _P2 is a point spaced downward from the upper end P _U of the short side member 3121 by a second distance S2 that is longer than the first distance _S1 . Therefore, the second inclined surface _{sf2 can} be explained as extending from the second point P2 spaced downward from the upper end P _U of the short side member 3121 by the _second distance _S2 to the lower end P _L of the short side member 3121. The second distance _S2 is preferably more than 40% and not more than 50% of the height H ₁ of the short side member 3121. Therefore, the second inclined surface _sf2 is extended downward from the second point P2 spaced downward from the upper end P _U of the short side member 3121 by a _second distance S2 that is more than 40% and not more than 50% of the height H ₁ of the _short side member 3121 to the lower end P _L of the short side member 3121.

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 or is constant in the vertical direction.
The intermediate surface cf extends from the first point _P1 to the second point _P2 . In other words, the intermediate surface cf extends downward from the upper end _PU of the short side member 3121 from a point (first point _P1 ) spaced apart by the _first distance S1 to a point (second point _P2 ) spaced apart by the _second distance S2. Such an intermediate surface cf may be provided so as not to be inclined, i.e., so as to be perpendicular to the ground, when the short side member 3121 is placed in a state perpendicular to the ground as shown in FIG. 5 .

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 caused by the first inclined surface sf1 is added to the reduction rate caused by the inclination of the short side member 3121 in the reduction rate of the length of the internal space IS in the long side direction of the mold ₃₀₀₀ decreasing as it moves downward.

Therefore, when the first inclined surface _sf1 is provided on the short side member 3121, the rate of _decrease in the length of the internal space of the mold 3000 in the long side direction (X-axis direction) as it progresses downward is larger than when the inclined surface _sf1 is not provided. Therefore, when the first inclined surface sf1 is provided on the short side member 3121, the compensation rate of solidification shrinkage in the long side direction of the mold 3000 is further improved compared to 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 severely. This makes it possible to suppress or prevent the formation 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.

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.

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.

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, and 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 the solidification shrinkage in the center of the internal space IS of the mold 3000 may not be sufficiently compensated.

Furthermore, if the first inclined surface _sf1 is extended to the second point _P2 , there is a risk of an inconvenience occurring in which over-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 Figures 2, 3 and 6.

Hereinafter, the short side portion including the short side member and the protruding member will be described with reference to Figs. 2, 3, 8 and 9.
Figure 8 is a diagram relating to the first embodiment of the present invention, where (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).

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.

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

The width PW of the convex member 3122 is set smaller than the width SW of the short side member 3121, as shown in (a) and (b) of Fig. 8. Therefore, as shown in (b) of Fig. 8, the inner surface if of the short side member 3121 is present on the outer side in the width direction of the convex member 3122. Note that the width PW of the convex member 3122 is set constant in the up-down direction, as shown in (b) and (d) of Fig. 8. Therefore, as shown in (b) of Fig. 8, 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 extends downward from the upper end _PU of the inner surface if of the short side member 3121, and is formed so that its protruding length PL decreases as it progresses downward, as shown in (c) and (d) of Figure 8. That is, the protruding length PL of the protruding member 3122 is shorter at the lower part than at the upper part. It is preferable that the protruding length PL of the protruding member 3122 decreases as it progresses downward, and the decreasing gradient is constant, as shown in (c) of Figure 8.

The extension length of the convex member 3122 in the vertical direction is shorter than the height _H1 of the short side member 3121. That is, the convex member 3122 extends downward from the upper end P _U of the short side member 3121 to one point (hereinafter, the third point P ₃ ). At this time, the distance between the upper end P _U of the short side member 3121 and the third point P ₃ (hereinafter, the third distance S ₃ ) is longer than the first distance S ₁ and shorter than the second distance S _2. More specifically, the third distance S ₃ may be 30% or more and 40% or less of the height H ₁ of the short side member 3121. Therefore, the third point P ₃ can be described as a point spaced downward from the upper end P _U of the short side member 3121 by a length of 30% or more and 40% or less of the height H ₁ of the short side member 3121. That is, the protruding member 3122 is extended so that the separation distance S ₃ between the upper end P _U of the short side member 3121 and the third point P ₃ is 30% or more and 40% or less of the height H ₁ of the short side member 3121 .

In this way, the convex member 3122 is formed on the inner side 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 side of the short side portion 3120 becomes longer than in the conventional case. Here, the inner side 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 side surface if of the short side member 3121 positioned outside the convex member 3122 in the width direction. The extension length SIL of the inner side surface if of the short side portion 3120 means the length of a path from one end _E1 , which is one of both ends of the inner side surface of the short side portion 3120 in the Y-axis direction, to the other end _E2 , as shown in FIG. 9(a).

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.

On the other hand, the short side member 3121 is provided so that its width decreases as it moves downward. Therefore, the length of the short side direction of the internal space of the mold 3000 decreases as it moves downward. In this case, when the short side member 3121 is provided with the convex member 3122, the rate at which the length of the short side direction of the internal space IS of the mold 3000 decreases as it moves downward becomes even greater than when the convex member is not provided. This is because, in the rate at which the length of the short side direction of the internal space IS of the mold 3000 decreases as it moves downward, the rate at which the width of the short side member 3121 is reduced is added to the rate at which the protruding length PL decreases as it moves downward.

Therefore, the mold 3000 can compensate for more solidification shrinkage in the short side direction by using the convex member 3122. In other words, by arranging the convex member 3122 on the short side member 3121, it is possible to compensate for more solidification shrinkage in the short side direction. This improves the compensation rate of solidification shrinkage in the short side direction of the mold 3000. This makes it possible to suppress or prevent the formation of gaps between the short side solidified shell SC and the long side member 3111, and to suppress or prevent the occurrence of surface cracks and breakouts due to shrinkage of the solidified shell.

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, 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 thereto, and the first inclined surface _sf1 may be formed 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 move away from the outer surface of as it progresses downward, and it is preferable that the gradient is changed at least once. In other words, it is preferable that the first inclined surface _sf1 is formed so that the gradient changes with respect to one point (first inflection point _IP1 ) between the upper end P _U of the short side member 3121 and the first point _P1 . In this case, the gradient of the lower region is set smaller than the gradient of the upper region with respect to the first inflection point _IP1 . In this way, when one first inflection point _IP1 is provided between the upper end P _U of the short side member 3121 and the first point P ₁ , the first inclined surface _sf1 can be described as being provided to have two inclination stages. The first inclined surface _sf1 is not limited to being provided to have two inclination stages, and may be provided to have three or more inclination stages. For this reason, two or more first inflection points _IP1 may be provided.

In the first embodiment, 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 of the short side member 3121. However, the present invention is not limited to this, and the second inclined surface _sf2 may be formed 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 changed at least once. In other words, the gradient of the second inclined surface _sf2 changes with respect to one point (second inflection point _IP2 ) between the second point _P2 and the lower end P _L of the short side member 3121. At this time, the second inclined surface _sf2 is formed so that the gradient of the lower region is larger than the gradient of the upper region with respect to the second inflection point IP2. In this way, when one second inflection point _IP2 is provided between the second point _P2 and the lower end _PL of the short side member 3121, 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.

Furthermore, in the above-described first embodiment, it has been described that the protruding length PL of the protruding member 3122 decreases at a constant rate from the upper end _PU of the short side member 3121 to the third point _P3 . That is, the protruding member 3122 according to the first embodiment is provided so as to have a constant inclination from the upper end _PU of the short side member 3121 to the third point _P3 .
However, the present invention is not limited thereto, and the convex member 3122 may be provided to have a multi-stage incline, as in the third modified example shown in FIG. 12. That is, the convex 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. In other words, the convex member 3122 may be formed so that its gradient changes at least once when it is extended from the upper end of the short side member 3121 to the third _{point P3} . That is, the convex member 3122 is formed so that the gradient changes with respect to one point (third inflection point _IP3 ) between the upper end P _U of the short side member 3121 and the third point _P3 . It is preferable that the gradient of the lower region is set larger than the gradient of the upper region with respect to the third inflection point IP3.

The third inflection point _IP3 may be, for example, the same as the first point _P1 as shown in Fig. 12. Needless to say, the third inflection point _IP3 may be at any position between the upper end _PU of the short side member ₃₁₂₁ and the third point P3.
In this way, when one third inflection point _IP3 is provided between the third point _P3 and the lower end _PL of the short side member 3121, the convex member 3122 has two inclination stages in the up-down direction. Needless to say, the convex member 3122 is not limited to having two inclination stages, and may have three or more inclination stages. For this reason, two or more third inflection points _IP3 may be provided.

Figures 13 to 15 are diagrams showing the short side portions of the mold according to the fourth to sixth modified examples of the first embodiment, where (a) to (d) of Figures 13 to 15 are diagrams similar to 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 the same in the vertical direction. However, the present invention is not limited to this, and the width PW of the convex member 3122 may decrease as it progresses downward, as in the fourth to sixth modified examples shown in Figures 13 to 15. In other words, the convex member 3122 may have a shape in which its protruding length PL decreases as it progresses downward, and at the same time, its width PW also decreases as it progresses downward.

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. For this reason, 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 that does not have 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 Fig. 14 and Fig. 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 fact that the boundary line DL is 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.

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 first embodiment, a configuration has been described in which 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 at all, and not only the short side member 3121 but also 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, as in the second embodiment shown in Figures 16 and 17. 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 first and second long sides 3110 with convex members 3112 , and first and second short sides 3120 with convex members 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.

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 the 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. At this time, the contents that overlap with the above-mentioned embodiments will be omitted or simplified.

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 an inner surface if on which first and second inclined surfaces _sf1 , _sf2 and an intermediate surface cf are provided and protruding members 3123 are provided at the corners, and a convex member 3122 protruding from the inner surface if of the body 3100 toward the internal space IS such 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. In addition, 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.

The protruding members 3123 protrude from the inner side surface if of the body 3100 toward the internal space, but may protrude from the inner side surface if of the short side member 3121 as shown in Figures 18 and 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. In other words, the protruding members 3123 protrude from the inner side surfaces if of both peripheral edges of the short side member 3121 toward the internal space IS of the mold 3000 with reference to the Y-axis direction. 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 (CHAMFERED MOLD), a protruding member 3112 may also be attached to the long side portion 3110 .

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

According to the mold 3000 of 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 rate 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 a gap from being generated 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.

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 the formation of a gap between the inner surface of the mold and the solidified shell due to the shrinkage of the solidified shell, and the phenomenon of delayed solidification caused by this can be suppressed or prevented. This makes it possible to suppress or prevent the occurrence of defects on the surface of the cast piece and the occurrence of breakouts.

1: slab 10: ladle 20: tundish 22: nozzle 40: cooling section 41: segment
3000: Mold
3100: Body 3110: Long side portion 3111: Long side member 3112: Protruding member (disposed on long side member) 3120: Short side portion 3121: Short side member 3122: Protruding member (disposed on short side member) 3123: Protruding member C: Solidified shell cf: Mid-surface DL: Boundary line E ₁ : One end in the Y-axis direction of the inner surface of the short side portion 3120 E ₂ : The other end in the Y-axis direction of the inner surface of the short side portion 3120 H ₁ : Height of the body if: Inner surface IP ₁ : First inflection point IP ₂ : Second inflection point IP ₃ : Third inflection point IS: Internal space LC: Long side solidified shell M: Molten steel of: Outer surface P ₁ : First location P ₂ : Second location P ₃ : third location PL: protruding length _PL : lower end of inner surface of body _PU : upper end of inner surface of body PW: width (of convex member) _S1 : first distance _S2 : second distance _S3 : third distance SC: narrow side solidified shell _sf1 : first inclined surface _sf2 : second inclined surface SIL: extension length (length from one end _E1 to the other end _E2 of the narrow side portion)
SL: Distance SW: Width, extension length in the Y-axis direction

Claims (14)

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 extends from an upper end (P _U ) of the inner surface of the body to a first point (P ₁ ) spaced apart by a first distance (S ₁ );
The second inclined surface is located below the first point (P ₁ ) and extends from a second point (P ₂ ) spaced apart from an upper end (P _U ) of the inner surface of the body by a second distance (S ₂ ) to a lower end (P _L ) of the inner surface of the body,
The first distance (S ₁ ) and the second distance (S ₂ ) are shorter than the height (H ₁ ) of the body,
The width of the protruding member is shorter than the width of the body,
The protruding member extends from an upper end (P _U ) of the inner surface of the body to a third location (P ₃ ) spaced apart by a third distance (S ₃ ),
The mold, wherein the third distance (S ₃ ) is greater than the first distance (S ₁ ) and less than the second distance (S ₂ ). 2. The mold according to claim 1, characterized in that the first distance ( _S1 ) is greater than or equal to 15% and less than or equal to 25% of the height ( _H1 ) of the body. the first inclined surface has a shape whose inclination gradient changes with respect to a first inflection point (IP 1 ) between an upper end (P _U ) of the inner surface of the body and the first point (P ₁ ) _;
The mold according to claim 1, characterized in that, in the first inclined surface, an angle between a lower region of the first inflection point (IP ₁ ) and the outer surface is smaller than an angle between an upper region of the first inflection point (IP ₁ ) and the outer surface. The mold according to claim 3, characterized in that a plurality of the first inflection points (IP ₁ ) are provided, and the plurality of first inflection points (IP ₁ ) are provided at different positions between an upper end (P _U ) of the inner surface of the body and the first point (P ₁ ). 2. The mold according to claim 1, characterized in that the second distance ( _S2 ) is greater than or equal to 40% and less than or equal to 50% of the height ( _H1 ) of the body. the second inclined surface has a shape whose inclination gradient changes with respect to a second inflection point (IP ₂ ) between the second point (P ₂ ) and a lower end (P _L ) of the inner surface of the body;
The mold according to claim 1, characterized in that, in the second inclined surface, an angle formed between a lower region of the second inflection point ( _IP2 ) and the outer surface is larger than an angle formed between an upper region of the second inflection point ( _IP2 ) and the outer surface. The mold according to claim 6, characterized in that a plurality of the second inflection points ( _IP2 ) are provided, and the plurality of second inflection points ( _IP2 ) are provided at different positions between the second point ( _P2 ) and a lower end (P _L ) of the inner surface of the body. The mold according to claim 1, characterized in that 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. 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. 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. The mold according to claim 9, characterized in that 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 the corners of the cast piece to be cast. 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. The gradient of the decrease in the protruding length as the protruding member advances downward changes with respect to a third inflection point (IP ₃ ) between the upper end (P _U ) of the body and the third point (P ₃ );
The mold according to claim 1, wherein in the convex member, an angle between a lower region of the third inflection point (IP ₃ ) and an outer surface is larger than an angle between an upper region of the third inflection point (IP ₃ ) and an outer surface. The mold according to claim 13, characterized in that a plurality of the third inflection points ( _IP3 ) are provided, and the plurality of the third inflection points ( _IP3 ) are provided at different positions between an upper end ( _PU ) of the inner surface of the body and the third point ( _P3 ).

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