Mold, mold manufacturing method, and cast piece

Abstract

An embodiment of the present invention is a mold having an internal space into which molten steel can be poured, comprising a body having the internal space and a protruding member formed to protrude from the body toward the internal space and extend in the width direction of the body. The protruding member includes a pair of side regions located on one side and the other side of a center in the width direction, and each of the pair of side regions has a shape in which the protruding length decreases with increasing distance from the center. Furthermore, the inner surfaces of the pair of side regions have a curved surface in the shape of 1 / 2 of a cosine curve with one period of 360°. Therefore, according to the embodiment of the present invention, when producing a cast slab that is to be rolled into a steel plate, it is possible to produce a cast slab that can suppress edge seam defects in the steel plate that occur due to width expansion of the cast slab.

Description

[Technical Field]

[0001] The present invention relates to a mold and a method for manufacturing a mold, and more particularly to a mold and a method for manufacturing a mold that can effectively control the shape of a cast piece and prevent the outflow of molten steel.

[0002] The present invention relates to a cast slab, and more particularly to a cast slab that can suppress the occurrence of edge seam defects (linear defects) in a steel plate produced by rolling the slab, which is caused by the slab spreading during rolling. [Background technology]

[0003] The molten steel is cooled in the mold to produce a slab, which is then withdrawn from the mold. The withdrawn slab moves along a cooling zone, where it is secondarily solidified by the cooling water sprayed onto it. The solidified slab is then cut to a specified length and rolled in a rolling mill. The rolled slab is called a steel plate.

[0004] In the rolling mill, the slab is positioned between an upper roll and a lower roll, and is rolled by the downward force of the upper roll and the upward force of the lower roll. Each of the upper roll and the lower roll extends in the width direction of the slab. A plurality of upper rolls are arranged lengthwise above the slab, and a plurality of rolls are arranged lengthwise below the slab.

[0005] On the other hand, when the upper and lower rolls press the slab, a width spreading phenomenon occurs in which both widthwise edge portions of the slab are crushed and spread outward. Such width spreading of the slab causes wrinkle-like edge seam defects to occur in the both widthwise edge regions of the steel sheet. Therefore, both widthwise edge portions of the steel sheet with edge seam defects are cut off before delivery to the customer. However, cutting off both widthwise edge portions of the steel sheet in this way causes a problem of a decrease in actual yield.

[0006] In order to solve the problem of edge seam defects caused by the width expansion of a slab during rolling, a convex member is provided on the inner surface of the mold. That is, a convex member that protrudes toward the internal space of the mold is provided on the inner surface of one of the long-side and short-side members that make up the mold. In this case, the longer the length that the convex member protrudes toward the internal space, the more the width expansion of the slab during rolling is suppressed, and the more the occurrence of edge seam defects in the steel sheet can be reduced.

[0007] On the other hand, the longer the protruding length of the convex member, the smaller the angle between the edge of the inner surface of the convex member facing the internal space and the inner surface of the long-side member. Therefore, the longer the protruding length of the convex member, the narrower the distance between the edge of the inner surface of the convex member and the inner surface of the long-side member, i.e., the narrower the space between the edge of the inner surface of the convex member and the inner surface of the long-side member, resulting in a generally triangular shape. The narrower the space between the edge of the inner surface of the convex member and the inner surface of the long-side member, the more likely it is that molten steel or a solidified shell will be trapped in the space between the edge of the inner surface of the convex member and the inner surface of the long-side member. Furthermore, such trapped molten steel or a solidified shell can cause an operational accident in which the slab breaks in the mold, causing the molten steel to spill out of the mold. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 2586769 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention provides a mold and a method for manufacturing the mold that can effectively control the shape of a cast piece and prevent the outflow of molten steel.

[0010] The present invention provides a cast slab that can suppress the occurrence of edge seam defects in a steel plate that is to be formed into a steel plate through a rolling process. [Means for solving the problem]

[0011] An embodiment of the present invention is a mold having an internal space into which molten steel can be poured, comprising: a body having the internal space; and a convex member formed to protrude from the body toward the internal space and extend in the width direction of the body, wherein the convex member includes a pair of side regions located on one side and the other side of a center in the width direction, each of the pair of side regions having a shape such that the protruding length decreases with increasing distance from the center, and the inner surfaces of the pair of side regions have a curved surface shaped like 1 / 2 of a cosine curve with one period equal to 360°.

[0012] The convex member includes a central region located between the pair of side regions, the protruding length of the central region is the same in the width direction, and the inner surface of the central region, which is the surface facing the internal space, has a flat shape.

[0013] The pair of side regions are symmetrical in shape with respect to the central region.

[0014] One of the pair of side regions has an inner surface shaped like a 0° to 180° section of one cycle of a cosine curve, and the other has an inner surface shaped like a 180° to 360° section of one cycle of a cosine curve.

[0015] The body comprises a pair of long side members, each extending in one direction and arranged to face each other in a direction intersecting the extension direction, and a pair of short side members, each extending to intersect the long side members and arranged to face each other so as to seal the space between the pair of long side members, and the convex member is formed to protrude from the short side member toward the internal space.

[0016] The angle formed between the inner surface of the long side member and the edge of the inner surface of the side region is 90°.

[0017] The protruding length of the central region of the convex member exceeds 5 mm.

[0018] The width of the convex member is equal to the width of the short side members, and the width of the central region of the convex member is 10% to 15% of the width of the short side members.

[0019] The width of the short side members and the convex members decreases as they go downward, and the width of the central region of the convex members is equal in the vertical direction.

[0020] The width of the short side members and the convex members decreases as they progress downward, and the width of the central region of the convex members decreases as they progress downward.

[0021] The vertical length of the convex member is the same as the vertical length of the short side member.

[0022] An embodiment of the present invention is a method for manufacturing a mold having a body with an internal space and a convex member formed to protrude from the body toward the internal space, the method including the steps of creating a design plan for the convex member to have first and second side regions whose protruding length decreases as it progresses toward both ends of the center in the width direction, and for the inner surfaces of each of the first and second side regions to have a curved surface shaped like half a cosine curve with a period of 360°, and processing a base material to have the shape of the convex member included in the design plan.

[0023] The process of creating the design plan is to determine the width W of the body to be manufactured. m and vertical length H m and providing a design for the inner surface of the convex member including shapes for the inner surfaces of the first and second side regions.

[0024] The process of designing the inner surface of the convex member is performed by determining the protrusion length T of the central region in the width direction of the convex member to be manufactured. c and width W c and determining the determined body width W m , the determined protrusion length T of the central region of the convex member c and width W cand providing a design for the first side region using the design formula (1) so that the shape of the inner surface of the first side region is half the shape of one period of a cosine curve.

[0025] The step of providing a design for the first side region includes: m and the determined width W of the central region c to determine the width W for the first side region to be produced. s and determining the width W of the first side region. s , the determined protrusion length T of the central region c a step of providing a cosine curve equation including a position X in the width direction of the convex member and a position Y in the thickness direction of the convex member; and a step of calculating a position Y in the thickness direction according to the position X in the width direction using the cosine curve equation, wherein the value of the position X in the width direction applied to the cosine curve equation is calculated based on the determined body width W m The determined width W of the first side region from one end of the s The value is a value in a section up to a point that is a distance corresponding to the distance, and multiple values are applied in the section.

[0026] The process of creating a design for the first side region includes a process of connecting a plurality of thickness direction positions Y calculated for each width direction position X to generate a design line for the first side region having a shape of half of a cosine curve with one period.

[0027] The step of creating a design for the inner surface of the convex member includes a step of creating a design for a central region, which is a design for the inner surface of a central region located between the first and second side regions, and the step of creating the design for the central region includes a step of creating a design for the central region from an end of a design line for the first side region to a width W of the determined central region. c Extending the line by an amount commensurate with the distance to generate the design line for the central region.

[0028] The method includes a step of creating a design for the second side region so that the shape of the inner surface of the second side region is half the shape of a cosine curve with one period, and the step of creating a design for the second side region includes a step of forming a design line for the second side region so that the design line is symmetrical with respect to the design line for the first side region, with the central region as the center.

[0029] The width of the body is determined as follows: m and the length in the thickness direction intersecting with the width direction is the determined protrusion length T c The step of processing the base material includes a step of providing a base material having a width W of the determined side region from both ends in a width direction on one surface of both surfaces in a thickness direction of the base material. s The process includes a step of processing the first and second side regions so that the shape up to a point separated by an amount corresponding to the length of the first and second side regions corresponds to the design line for the first and second side regions.

[0030] An embodiment of the present invention is a cast slab produced by solidifying molten steel, wherein both surfaces of the cast slab are concave and recessed inward, and a portion of each of the both surfaces has a curved surface in the shape of half a cosine curve with one cycle of 360°.

[0031] Each of the two surfaces includes a central surface and a pair of side surfaces located on one side and the other side of the central surface, each of the pair of side surfaces having a curved surface shaped like half a cosine curve with one period of 360°, and the central surface having a flat surface.

[0032] The pair of side surfaces have shapes symmetrical with respect to the central surface, one of the pair of side surfaces having a shape of one cycle of a cosine curve in the range of 0° to 180°, and the other having a shape of one cycle of a cosine curve in the range of 180° to 360°. [Effects of the Invention]

[0033] The mold according to the embodiment of the present invention can produce a cast slab that can suppress edge seam defects in the steel plate caused by width expansion when the cast slab is rolled into a steel plate. Furthermore, during the production of a cast slab by solidifying molten steel inside the mold, or when the width of the mold is variable, it can suppress or prevent steel or a solidified shell from being trapped in the space between the inner surface of the edge of the convex member and the inner surface of the long side member. This can prevent operational accidents in which the molten steel leaks out of the mold due to breakage of the cast slab. In other words, the mold according to the embodiment of the present invention can produce a cast slab that can suppress edge seam defects in the steel plate, and can also prevent operational accidents due to leaking molten steel. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a diagram showing a casting apparatus including a mold according to an embodiment of the present invention; [Figure 2] 1 is a three-dimensional view showing a mold according to an embodiment of the present invention. [Figure 3] 3 is a front view seen from the "A" side in FIG. 2 to explain the arrangement of the first and second short-side members. FIG. [Figure 4] FIG. 3 is a front view seen from the "B" side in FIG. 2 to explain the shape of the short-side member. [Figure 5] FIG. 1 is a diagram conceptually showing a state in which defects occur at the edge portions in the width direction of a steel plate obtained by rolling a cast slab. [Figure 6] (a) is a three-dimensional view showing the short side portion according to an embodiment of the present invention, (b) is a plan view of the short side portion shown in (a) viewed from the heights of circles a, b, and c, which are different from each other, and (c) is a front view of the convex member of (a) viewed from the "C" side. [Figure 7] FIG. 2 is a plan view of a short side portion according to an embodiment of the present invention, viewed from above. [Figure 8](a) is a three-dimensional view showing the short side portion of a modified embodiment, (b) is a plan view of the short side portion shown in (a) viewed from the heights of circles a, b, and c, which are different from each other, and (c) is a front view of the convex member of (a) viewed from the "C" side. [Figure 9] 5(a) to 5(c) are diagrams showing a procedure for creating a design plan for the inner surface of a convex member in order to manufacture a short side portion provided with the convex member according to an embodiment of the present invention. [Figure 10] 1 is a cast piece produced using a mold according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] 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 disclosed below, and may 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.

[0036] FIG. 1 is a diagram showing a casting apparatus equipped with a mold according to an embodiment of the present invention.

[0037] Referring to 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.

[0038] The casting apparatus also includes a cooling section 40 disposed below the mold 3000, which sprays cooling water onto the strand 1 extracted from the mold 3000 to completely solidify it. Here, the cooling section 40 may be a means including 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 of moving the strand 1, and nozzles positioned between the plurality of rolls that spray cooling water onto the strand 1.

[0039] The cast slab 1 produced in the casting device is transported to a rolling device and rolled, thereby producing a steel plate.

[0040] A mold according to an embodiment of the present invention will be described below with reference to FIGS.

[0041] Fig. 2 is a three-dimensional view showing a mold according to an embodiment of the present invention. Fig. 3 is a front view seen from side "A" in Fig. 2 to explain the arrangement of first and second short-side members. Fig. 4 is a front view seen from side "B" in Fig. 2 to explain the shape of the short-side members.

[0042] 2, the mold 3000 may include a body 3100 and a convex member CV formed to protrude from the inner surface of the body 3100 toward the interior space. The mold 3000 may also include a cooling water flow path (not shown) embedded inside the body 3100 so that cooling water can circulate.

[0043] Referring to Figure 2, the body 3100 comprises first and second short side members 3121, each extending in one direction (X-axis direction) and spaced apart from each other, aligned in a direction (Y-axis direction) intersecting the extension direction, and first and second long side members 3111, each extending in a direction (Y-axis direction) intersecting or perpendicular to the extension direction (X-axis direction) of the first and second short side members 3121, aligned in the extension direction of the first and second short side members 3121, and spaced apart from each other.

[0044] The first and second short side members 3121 may be provided so that their extension lengths are shorter than the first and second long side members 3111. In other words, the extension lengths of the first and second short side members 3121 in the X-axis direction may be even shorter than the extension lengths of the first and second long side members 3111 in the Y-axis direction.

[0045] The body 3100 is formed in a tube shape having an internal space IS by connecting or coupling the first and second long side members 3111 and the first and second short side members 3121 to each other. For example, with reference to the X-axis direction, one end of each of the first and second short side members 3121 is connected to the inner surface of the first long side member 3111, and the other end is connected to the inner surface of the second long side member 3111. The first short side member 3121 and the second short side member 3121 are arranged side by side and spaced apart in the Y-axis direction. The first short side member 3121 and the second short side member 3121 are arranged such that the distance between the first long side member 3111 and the second long side member 3111 is greater than the distance between the first long side member 3111 and the second long side member 3111. This results in a body 3100 having an internal space IS that is rectangular in shape. More specifically, a body 3100 is provided having a rectangular internal space IS whose length in the Y-axis direction is longer than its length in the X-axis direction.

[0046] Hereinafter, the extension direction of each of the long side members 3111 and the short side members 3121 is defined as the width direction. Therefore, the length of each of the long side members 3111 and the short side members 3121 in the extension direction can be defined as the "width." Therefore, the width of the long side member 3111 is the length in the Y-axis direction, and the width of the short side member 3121 is the length in the X-axis direction. Furthermore, the direction intersecting the extension direction of each of the long side members 3111 and the short side members 3121 is defined as the thickness direction. Therefore, the length of each of the long side members 3111 and the short side members 3121 in the direction intersecting the extension direction can be defined as the "thickness." Therefore, the thickness of the long side member 3111 is the length in the X-axis direction, and the thickness of the short side member 3121 is the length in the Y-axis direction.

[0047] When the first short side member 3121 and the second short side member 3121 are arranged to face each other, they are arranged so that the separation distance G decreases toward the bottom, as shown in Fig. 3. Therefore, the first and second short side members 3121 can be arranged so as to be inclined or slanted.

[0048] Therefore, the length of the long side direction (length in the Y-axis direction) of the internal space IS of the mold 3000 decreases toward the bottom. In this manner, by arranging the first and second short side members 3121 so that the separation distance G between them decreases toward the bottom, it is possible to compensate for the contraction of the solidified shell in the long side direction. More specifically, when the solidified shell (long side solidified shell) formed by solidifying molten steel along the first and second long side members 3111 contracts in the extension direction of the first and second long side members 3111, the contraction can be compensated for. This makes it possible to suppress the generation of a gap between the inner surface of the body 3100 and the solidified shell due to the contraction of the solidified shell in the long side direction, thereby suppressing the delay in solidification and the occurrence of defects caused thereby.

[0049] As shown in FIG. 4, each of the first and second short-side members 3121 has an extension length, i.e., a width W m In other words, the extension length W of each of the first and second short side members 3121 in the X-axis direction, which is the short side direction of the mold 3000, decreases as the length W decreases toward the bottom. m The first and second short side members 3121 are disposed so that the distance between them decreases as they extend downward. Therefore, one side surface and the other side surface of the first and second short side members 3121 are disposed so that they are inclined with respect to the X-axis direction. That is, the side surfaces of the first and second short side members 3121 are inclined so that they approach the center in the width direction as they extend downward. The first and second long side members 3111 are connected to the side surfaces of the first and second short side members 3121, respectively. Therefore, the first and second long side members 3111 are disposed so that the distance between them decreases as they extend downward.

[0050] The reason for forming the side surfaces of the narrow-side member 3121 to be inclined and for the first and second long-side members 3111 disposed to abut against the narrow-side member 3121 to approach each other as they move downward is to compensate for the contraction of the solidified shell in the narrow-side direction. That is, this is to compensate for the contraction of the solidified shell (narrow-side solidified shell) formed by solidifying the molten steel formed along the first and second narrow-side members 3121 when the solidified shell contracts in the extending direction of the first and second narrow-side members 3121. This makes it possible to suppress the generation of a gap between the inner surface of the body 3100 and the solidified shell due to the contraction of the solidified shell in the narrow-side direction, thereby suppressing the delay in solidification and the occurrence of defects due to this.

[0051] The convex members CV may be provided on the inner surfaces of the first and second short side members 3121, which are components of the body 3100. Hereinafter, the components having the short side members 3121 and the convex members CV disposed on the short side members 3121 are defined as short side portions 3120. Therefore, the mold 3000 can be described as having first and second short side portions 3120, each having a convex member CV, and first and second long side members 3111.

[0052] The body 3100 has an inner surface IF, which faces the internal space IS and is in direct contact with the molten steel or the solidified shell, and an outer surface OF, which is the opposite surface of the inner surface IF and is exposed to the outside. Here, the outer surface OF of the body 3100 may refer to the outer surfaces OF of the first and second long side members 3111 and the outer surfaces OF of the first and second short side portions 3120. Furthermore, the outer surfaces OF of the first and second short side portions 3120 refer to the surfaces of both the first and second short side members 3121 in the Y-axis direction that are located opposite the convex member CV. Therefore, the outer surfaces OF of the short side portions 3120 may refer to the surfaces of the first and second short side members 3121 that are located opposite the convex member CV.

[0053] Furthermore, the inner surface IF of the body 3100 may refer to the inner surfaces IF of the first and second long side members 3111 and the inner surfaces IF of the first and second short side portions 3120. Here, the inner surfaces IF of the first and second short side portions 3120 refer to the surfaces of the convex member CV that face the internal space IS. More specifically, the convex member CV is formed to protrude from the inner surface of the short side member 3121 toward the internal space IS. Therefore, of the two surfaces of the convex member CV in the Y-axis direction, the surface that faces the short side member 3121 can be defined as the outer surface, and the surface on the opposite side from the short side member 3121 can be defined as the inner surface IF. Therefore, the inner surface IF of the short side portion 3120 may refer to the surface of the convex member CV that faces the opposite side from the short side member 3121 or the surface that faces the internal space IS.

[0054] FIG. 5 is a conceptual diagram showing a state in which edge seam defects occur at the edge portions in the width direction of a steel plate obtained by rolling a cast slab.

[0055] Meanwhile, the produced slab 1 is cut to a predetermined length and then loaded into a rolling mill for rolling. The slab 1 loaded into the rolling mill is pressed in the thickness direction by an upper roll and a lower roll and rolled. In this way, a steel plate 2 is produced by rolling the slab 1. However, when the slab 1 is rolled, the edge portions in the width direction of the slab 1 are crushed and widened. This widening causes wrinkles in the edge portions in the width direction of the steel plate 2, as shown in Figure 5.

[0056] In order to suppress or prevent the occurrence of such wrinkle defects, a convex member has conventionally been provided on the inner surface of the short-side member. The convex member is formed so as to protrude from the inner surface of the short-side member toward the internal space, and is provided with a shape in which the protruding length decreases as it progresses toward the edge in the width direction. The shape of such a convex member is a roughly fan-shaped arc (circular arc). When molten steel is solidified using a mold in which convex members are formed on the short-side members, the shape of the short sides of the cast slab becomes concave.

[0057] Furthermore, by rolling a slab with concave short sides, the amount of width expansion can be reduced compared to when a slab with non-convex short sides is rolled, thereby making it possible to suppress the occurrence of edge seam defects at the edges in the width direction of the steel sheet.

[0058] On the other hand, the longer the protruding length of the convex member, the more effectively it can suppress width expansion during rolling, thereby suppressing the occurrence of wrinkle-like edge seam defects at the widthwise edge of the steel sheet. However, the longer the protruding length of the convex member, the smaller the angle between the edge of the inner surface of the convex member facing the internal space and the inner surface of the long-side member, and this angle may be acute. Therefore, the longer the protruding length of the convex member, the narrower the distance between the edge of the inner surface of the convex member and the inner surface of the long-side member, i.e., the narrower the space between the edge of the inner surface of the convex member and the inner surface of the long-side member. Furthermore, the shape of the space between the edge of the inner surface of the convex member and the inner surface of the long-side member may be pointed, roughly in a triangular shape. Furthermore, the smaller the space between the edge of the inner surface of the convex member and the inner surface of the long-side member, the more likely it is that molten steel or a solidified shell will be trapped in the space between the edge of the inner surface of the convex member and the inner surface of the long-side member. Furthermore, there is a risk that the slab may break inside the mold due to the molten steel or solidified shell getting caught, which may result in an operational accident in which the molten steel flows out of the mold.

[0059] Therefore, it is necessary to produce a cast 1 that can suppress the occurrence of defects in the steel sheet 2 and to provide a mold that can prevent operational accidents such as the spilling of molten steel. For this purpose, in an embodiment of the present invention, when providing a convex member CV on the inner surface of a short-side member 3121, a cast 1 that can suppress the occurrence of defects is produced and the convex member CV is provided so that the angle between the inner surface IF of the convex member CV at the edge in the width direction (X-axis direction) and the inner surface IF of the long-side member 3111 at the edge in the width direction (Y-axis direction) is 90° or a right angle. Then, to ensure that the angle between the inner surface IF of the convex member CV and the inner surface IF of the long-side member 3111 is 90° or a right angle, the shape of the inner surface IF of the convex member CV is made to be a cosine curve in the width direction.

[0060] Hereinafter, a short side portion according to an embodiment of the present invention will be described with reference to Figures 6(a) to 6(c) and 7. In this case, since the first short side portion and the second short side portion, which are arranged opposite each other, have the same configuration, shape, and size, one of the short side portions will be described as an example. For ease of explanation, they will not be simply referred to as the first and second short side portions or first and second short side members, but will be referred to as "short side portion" and "short side member."

[0061] Fig. 6(a) is a three-dimensional view showing a short side portion according to an embodiment of the present invention. Fig. 6(b) is a plan view of the short side portion shown in Fig. 6(a) viewed from different heights, i.e., circle a, circle b, and circle c. Fig. 6(c) is a front view of the convex member as viewed from the "C" side of Fig. 6(a). Fig. 7 is a plan view of the short side portion according to an embodiment of the present invention viewed from above.

[0062] As shown in FIG. 2 and FIG. 6(a), the convex member CV is formed so as to protrude from the inner surface of the short-side member 3121 toward the internal space IS. In other words, the convex member CV is provided so as to protrude in the Y-axis direction from the inner surface of the short-side member 3121. The convex member CV extends in the width direction of the short-side member 3121, i.e., in the X-axis direction. At this time, the convex member CV has an extension length in the X-axis direction, i.e., a width W cv is the width W of the short side member 3121 m is formed to be equal to

[0063] 6A, the convex member CV is formed on the inner surface of the short-side member 3121 so as to extend from the upper end to the lower end of the inner surface of the short-side member 3121. That is, the convex member CV has a height H cv is the height H of the short side member 3121 m In other words, the protruding member CV is provided so that its extension length H cvis set equal to the height of the short side member 3121. Therefore, the height of the upper end of the convex member CV can be the same as the height of the upper end of the short side member 3121, and the height of the lower end of the convex member CV can be the same as the height of the lower end of the short side member 3121. Furthermore, the protruding length of the convex member CV can be the same in the vertical direction.

[0064] Referring to (a) and (b) of FIG. 6, the convex member CV has a central region A c The protruding length of the convex member CV decreases from the center toward both ends. Furthermore, when the protruding length of the convex member CV decreases toward both end edges in the width direction, the rate of decrease is not constant but decreases unevenly. Therefore, the inner surface IF of the convex member CV facing the internal space IS is formed into a shape that includes a curved surface. The shape of the inner surface IF of the convex member CV extending in the width direction may include a curved line.

[0065] The convex member CV will be described in more detail below with reference to FIG.

[0066] The convex part CV is located in the central area A c , central region A c A first side region A located on one side of s1 and central region A c A second side region A located on the other side of s2 Includes.

[0067] central area A c The central region A may be a region including the center of the width direction of the convex member CV and a region including a section from the center to a point spaced a predetermined distance from the center to one side and the other side. c is the protruding length T in the width direction c In this case, the central region A c The protruding length T c In other words, in the convex member CV, the central region A c The inner surface IF of the central region A is spaced from the inner surface of the short-side member 3121 by a distance of more than 5 mm. cThe protruding length T c The gap should be set so that it is greater than 5 mm and less than 20 mm.

[0068] Central area A of convex part CV c As explained above, the protrusion length T c Therefore, the central region A of the convex member CV c The inner surface IF of the convex member CV may have a flat surface. c is the given width W c The width W of the short side member 3121 is m In other words, the central region A of the convex member CV is set to be 10% to 15% of the central region A of the convex member CV. c The length in the Y-axis direction of W c is the length W of the short side member 3121 in the Y-axis direction m It is set to be 10% to 15% of (W c =0.1W~0.15W).

[0069] central area A c The width direction protrusion length T c The central region A c The reason why the inner surface IF is formed to be flat is to measure the gradient of the short side portion 3120. More specifically, the distance between the pair of short side portions 3120 is adjusted before the start of casting depending on the type of steel or the size of the slab 1 to be produced.

[0070] In addition, when adjusting the gradient of each of the pair of short sides 3120 so that the distance between the pair of short sides 3120 decreases toward the bottom, the gradient of the short sides 3120 can be adjusted before the start of casting depending on the type of steel or the size of the slab to be produced. In this case, in order to arrange the short sides 3120 so as to achieve the desired gradient, it is necessary to measure the gradient of the short sides 3120.

[0071] For this purpose, the gradient measurement tool is brought into contact with the inner surface of the short side portion 3120. Therefore, when providing the convex member CV, the central region Ac The width direction protrusion length T c The central region A c The inner surface IF of the central region A is made flat. c A gradient measuring tool is brought into contact with the short side 3120 to measure the gradient of the short side 3120. The measured gradient of the short side 3120 is then adjusted to a target gradient.

[0072] On the other hand, the central region A of the convex part CV c Width W c is the width W of the short side member 3121 m If the difference exceeds 15%, there is a risk that the angle θ between the edge of the inner surface IF of the convex member CV and the edge of the inner surface IF of the long side member 3111 will become an acute angle of less than 90°. As a result, molten steel or a solidified shell will be trapped in the space between the edge of the inner surface IF of the convex member CV and the edge of the inner surface IF of the long side member 3111, causing fracture of the slab 1, which may lead to an operational accident in which the molten steel flows out of the mold 3000.

[0073] Conversely, the central region A of the convex member CV c If the width of the short-side member 3121 is less than 10% of the width of the short-side member, the area in which the angle of the short-side member 3121, i.e., the slope, can be measured is small, making the measurement difficult. This may result in an error in measuring the slope of the short-side member 3121.

[0074] First Side Area A s1 is the distance between one end of the convex part CV and the central area A c The second side area A is the area between one end of the s2 is the central region A c The first and second side regions A are the regions between the other end of the protruding member CV and the other end of the protruding member CV. s1 , A s2 Each of the protrusions has a widthwise protrusion length T s The first and second side regions A s1 , A s2 Each of the central region A cAs it moves away from the s More specifically, the first side region A s1 is the central region A c As the protrusion length T s The second side region A s2 is the central region A c As the protrusion length T s is set so as to decrease.

[0075] First and second side regions A s1 , A s2 The protruding length T s When the thickness of the first and second side regions A of the convex member CV decreases, the rate or amount of decrease is not constant, but decreases unevenly. s1 , A s2 The inner surface of the first and second side regions A is curved. s1 , A s2 The inner surface of the first and second side regions A is curved in the width direction in the shape of a cosine curve. s1 , A s2 Each of the inner surfaces of the first and second side regions A has a curved surface shaped like half of a cosine curve with one cycle of 360°. Here, "half of a cosine curve" can mean "half a period of a cosine curve with one cycle of 360°." s1 , A s2 Each of the inner surfaces can be described as a curved surface having a shape of half a period of a cosine curve with one period being 360°. Furthermore, half of a cosine curve with one period being 360° (half a period of a cosine curve) can refer to the curve in the range of 0° to 180° and the curve in the range of 180° to 360° in the cosine curve.

[0076] As described above, the first and second side regions A s1 , As2 Each of the inner surfaces of the first side region A is curved in the shape of half a cosine curve, that is, in the shape of a curved surface in the shape of a half period of a cosine curve. s1 The inner surface of the second side region A may have a shape of a 0° to 180° section of one cycle of a cosine curve. s2 The inner surface may have a shape corresponding to a 180° to 360° section of one cycle of a cosine curve.

[0077] First and second side regions A s1 , A s2 When the inner surface IF of the short side member 3121 is formed to have a shape of half of a cosine curve with one period of 360°, m , central region A of the convex part CV c Width W s and the central region A of the convex member CV c The protruding length T c This will be described again later with reference to FIG.

[0078] As described above, the central region A of the convex member CV c The protruding length T c The central region A is set to be greater than 5 mm, preferably greater than 5 mm and equal to or less than 20 mm. c The protruding length T c If the width is 5 mm or less, the effect of suppressing the width expansion during rolling of the slab 1 is weak, and therefore the effect of suppressing the occurrence of edge seam defects in the steel sheet may be weak.

[0079] Returning to (a) to (c) of Figure 6, the protruding member CV will be described. As described above, the protruding member CV is formed to have the same height as the short-side member 3121. That is, the protruding member CV is formed so as to extend from the upper end to the lower end of the short-side member 3121. The short-side member 3121 has a width W m decreases as it moves downward, and the convex part CV has a width W cv is set so that its width W is equal to that of the short side member 3121. Therefore, the width W of the convex member CV decreases as it goes downward. cvAt this time, the width W of the central region of the convex member CV decreases. c 6(b) and 6(c), the side regions A of the convex member CV may be provided so as to be equal in the vertical direction. s Width W s The central region A of the convex member CV may be set to decrease as it goes downward. c The protruding length T c are the same in the vertical direction, and the side area A s The protruding length T s may be the same in the vertical direction.

[0080] Fig. 8(a) is a three-dimensional view showing a short side portion according to a modified example of the embodiment. Fig. 8(b) is a plan view of the short side portion shown in Fig. 8(a) viewed from different heights, i.e., circle a, circle b, and circle c. Fig. 8(c) is a front view of the convex member viewed from the "C" side of Fig. 8(a).

[0081] In the above-described embodiment, the central region A of the convex member CV c Width W c However, the present invention is not limited to this case. c Width W c 8(a) to (c), the side region A S Width W S may be set to be equal in the vertical direction or to decrease as it goes downward. c Width W c is set to decrease as it progresses downward, the solidification shrinkage of the solidified shell can be adjusted more effectively than in the embodiment.

[0082] 9(a) to 9(c) are flow charts showing a method for preparing a design plan including a design for the inner surface of a convex member in order to manufacture a short side portion provided with the convex member according to an embodiment of the present invention.

[0083] Below, based on Figures 7 and Figures 9(a) to (c), we will explain a method for creating a design plan including a design for the inner surface of a convex member in an embodiment of the present invention, and a method for using this to create a short side portion.

[0084] First Side Area A s1 and the second side area A s2 The only difference between the first and second side regions A and B is their positions, and they are identical in shape and size. s1 width of the second side region A s2 Similarly, the width of s " and explain.

[0085] First, the width W of the short-side member 3121 to be manufactured m Also, the central area A for the convex part CV to be manufactured is determined. c The protruding length T c and central region A c Width W c Determine.

[0086] Central area A of convex part CV c The protruding length T c is determined in a range exceeding 5 mm, preferably in a range exceeding 5 mm and not exceeding 20 mm. c The protruding length T c is determined within the range of 10 mm or more and 20 mm or less.

[0087] In addition, the central region A of the convex member CV c Width W c is the width W of the short side member 3121 m In other words, the width W of the short side member 3121 is determined to be 10% to 15% of the width W of the short side member 3121. m Once the width W of the short side member 3121 is determined, m Using the central area A of the convex part CV c Width W c At this time, the width W of the short side member 3121 is determined. mThe value is determined to be 10% to 15% of the above.

[0088] And the width W of the short side member 3121 m and the central region A of the convex member CV c Width W c Once determined, this is used to determine the first side area A s1 Width W s Here, the first side area A s1 Width W s is the width W of the short side member 3121 m From the central area A of the convex part CV c Width W c The second side region A may be determined as half the length of the first side region A minus the length of the second side region A (see Equation 1). s2 Width W s is the first side region W s1 Width W s Therefore, the first side region W s1 Width W s Once this is determined, the second side area A s2 Width W s is determined automatically.

[0089]

number

[0090] In this way, the width W of the short side member 3121 m , central region A of the convex part CV c The protruding length T c and width W c , the first side region A of the convex member CV s1 Width W s Once this is determined, the first side region A to be manufactured using this is s1 That is, a design plan for the inner surface of the first side region A of the inner surface IF of the convex member CV facing the internal space IS is prepared. s1 A design plan is prepared so that the shape of the inner surface IF of the axial direction becomes the shape of one period of a cosine curve in the range of 0° to 180°.

[0091] At this time, a design proposal for the inner surface IF of the convex member CV may be prepared using an XY coordinate plane such as that shown in (a) to (c) of Figure 9. The XY coordinate plane may be a coordinate plane on the base material for manufacturing the short side portion. The X-axis direction on the XY coordinate plane may be the direction corresponding to the width direction of the short side member 3121 and the convex member CV in the mold 3000 to be manufactured, and the Y-axis direction may be the direction corresponding to the thickness direction of the short side member 3121 and the convex member CV.

[0092] Hereinafter, the point on the X-axis line of the XY coordinate plane where the X-axis value is "0" will be referred to as the "reference point X0." The "reference point X0" where the X-axis value is "0" may be the point at one end of the short side portion 3120, the short side member 3121, or the convex member CV.

[0093] Also, on the XY coordinate plane, the "X ws " is the position on the X-axis line, and is the distance from the reference point X0 to the side area A s Width W s In the following, for ease of explanation, the distance from the reference point X0 to the side area A s Width W s The point that is away from the boundary point X is ws "

[0094] Side area A on the XY coordinate plane s In order to design the inner surface IF of the first side area A, the value of the Y axis is determined according to the value of the X axis. s1 Width W s The value of the boundary point X ws The Y-axis values corresponding to the different X-values are determined.

[0095] The Y-axis value corresponding to the X-value is determined using a cosine curve formula. m , central region A in the convex part CV s The protruding length T cand width W c The Y-axis value corresponding to the X-axis value is calculated using a cosine curve equation (see Equation 2) to which the above equation is applied.

[0096]

number

[0097] In Formula 2, the central region A of the convex member CV c The protruding length T c is a value that has already been determined. In the formula 2, the first side region A of the convex member CV s1 Width W s is the width W of the short side member 3121 already determined m and the central region A of the convex member CV c Width W c (See Equation 1). In Equation 2, "X" is the value on the X axis, and is the distance from the reference point X0 to the boundary point X ws That is, in Equation 2, the value applied to X is 0 (zero) or more and the width W of the side region s is less than or equal to the value of (see relation 1).

[0098] [Equation 1] 0≦x≦W s

[0099] When determining the Y-axis value according to the X-value using Equation 2, as described above, Equation 2 is set to 0 (zero) or more, and the first side area A s1 Width W s By applying the following values and performing the calculation, the Y value corresponding to each X value can be calculated. ws In the section up to, the Y-axis value is calculated according to the X-axis value.

[0100] To give a concrete example, if you apply "0 (zero)" to X in formula 2, the Y value will be T c This is calculated as (0,T c / 2), where (0,T c The point with the coordinate value of (0,T / 2) is the point where the side region starts. c / 2) is the starting point P s It is called.

[0101] For example, if you apply "Ws" to X and calculate it, the Y value will be -T c This is calculated as (0, -T c / 2), where (0,-T c The point with the coordinate value of (0, -T / 2) is the boundary between the side region and the central region, and is the point where the side region ends. c / 2) is the end point P e It is called.

[0102] In the same way, we can substitute 0 (zero) and W for X in Equation 2. s If you apply the value between 0 (zero) and W, the Y value corresponding to each X will be calculated. s This will be explained by taking as an example the calculation of Y-axis values for ten different X-values among values less than 10. In this case, ten points P1, P2, ..., P9, P 10 is generated. That is, the starting point P s and end point P e There are ten different points P1, P2, ..., P9, P 10 is generated.

[0103] Therefore, as shown in FIG. 9(a), the starting point P s and end point P e , the starting point P s and end point P eMultiple points P1, P2, ..., P9, P 10 is generated.

[0104] Next, the starting point P s , multiple points P1, P2, ..., P9, P 10 and end point P e To generate a line, we connect the starting point P s and end point P e A curve connecting these points is generated, and the curve has a shape that is half of a cosine curve with one cycle of 360°. In other words, the curve has a shape that is the 0° to 180° section of one cycle of a cosine curve. In other words, the curve has a shape that is half a period of a cosine curve with one cycle of 360°, and a shape that is the 0° to 180° section.

[0105] Starting point P s , end point P e and multiple points P1, P2, ..., P9, P 10 The line of the cosine curve connecting the first side area A s1 (hereinafter referred to as the design line DL for the first side region) s1 In other words, the first side region A of the inner surface IF of the convex member CV s1 Design line DL for the first side region relative to the inner surface IF of s1 is.

[0106] Next, the central region A of the convex member CV is defined on the XY coordinate plane. c The design line for the inner surface IF of the c At this time, the end point P e Starting from the predetermined central area A c Width W c Therefore, the central region A c Design line DL for the central area to manufacture c is generated, and a design line DL for the central region is generated. cmay have the shape of a straight line in which the Y-axis value is constant depending on the X-axis value, as shown in FIG. 9(c).

[0107] Next, central region A c A second side region A is disposed on the other side of the s2 (hereinafter referred to as the design line DL for the second side region) s2 ) for the second side region. s2 When providing the center region design line DL c Therefore, as shown in FIG. 9(d), the design line DL for the second side region of the cosine curve shape is s2 is generated.

[0108] Thus, the design line DL for the first side region s1 , design line DL for the central region c and the design line DL for the second side region s2 The line connecting these is a design for the inner surface IF of the convex member CV (hereinafter referred to as the inner surface design). Therefore, the inner surface design is a design line DL s1 , design line DL for the central region c and the design line DL for the second design domain s2 It can be explained as including

[0109] And, the central region A of the short side member 3121 and the convex member CV c As you move downwards, the width W m , W cv The central region A c The protruding length T c Therefore, when designing the inner surface of the convex member CV, it is preferable to design it for each height. For this purpose, the width of the short side member 3121 and the central region A of the convex member CV are set for each height. c Width W m , W cv Then, the width W of the short side member 3121 for each height is determined. m, the central area A of the convex part CV by height c Width W cv , and the determined central region A c The protruding length T c Using this, the interior design is created for each height.

[0110] When the design line DL of the inner surface IF of the convex member CV is set, the short side portion 3120 including the short side member 3121 and the convex member CV is set using this. At this time, the width W of the short side member 3121 that is predetermined m , central region A of the convex part CV c Width W c , central region A of the convex part CV c The protruding length T c , and the side region A of the convex member CV s Width W s The short side member 3121 and the convex member CV are provided so as to have the following shape. Of both surfaces of the convex member CV in the thickness direction (Y-axis direction), the inner surface IF on the opposite side to the short side member 3121 is provided so as to have the same shape as the design of the inner surface provided in advance.

[0111] This will be explained in more detail below with a specific example.

[0112] First, a base material for providing the short side portion 3120 is prepared. Here, the base material may be a rectangular plate material made of copper (Cu). When preparing the base material, the width W of the short side member 3121, the length of which in one direction is predetermined, is determined. m and the length in the other direction intersecting with the one direction is predetermined. c The protruding length T c The time limit shall be set so as to exceed the limit.

[0113] Here, one direction of the base material is a direction corresponding to the width direction of the short-side member 3121, and the other direction of the base material is a direction corresponding to the thickness direction of the short-side member 3121. For this reason, one direction of the base material will be referred to as the width direction, and the other direction of the base material will be referred to as the thickness direction in the following description.

[0114] Next, the base material is processed. At this time, the means for processing the base material is not particularly limited, but for example, a ball-type cutter can be used.

[0115] When processing the base material, one of the two surfaces in the thickness direction of the base material is processed. At this time, the side regions A are formed by cutting the side regions A from both ends in the width direction of the one surface. s Width W s The shape of the design line DL for the side area is S1 , D.L. S2 That is, a curved surface having a shape of the 0° to 180° section of one cycle of a cosine curve is generated on one side of the central region in the width direction of the base material, and a curved surface having a shape of the 180° to 360° section of one cycle of a cosine curve is generated on the other side. In this way, the curved surfaces provided on both sides of the central region on one surface of the base material are formed in the side regions A of the convex member CV to be manufactured. s The central region on one surface of the base material corresponds to the central region A of the convex member CV to be manufactured. c corresponds to the inner surface of

[0116] Therefore, the predetermined width W m and a short-side member 3121 having a central region A c is a predetermined protrusion length T c and width W c and a first and second side region A s1 , A s2 and a short side portion 3120 having a convex member CV whose inner surface is formed in a cosine curve. s1 The inner surface of the second side region A is formed in the shape of a 0° to 180° section of one period of a cosine curve. s2 The inner surface is shaped in the 180° to 360° section of one cycle of a cosine curve.

[0117] As described above, the width W of the short side member 3121 m and the central region A of the convex member CV c Width Wc Therefore, the width W of the short side member 3121 determined in advance for each height must be set to decrease as it goes downward. m and the central region A of the convex member CV c Width W s In addition, the center area A of the short side member 3121 and the convex member CV is made according to the height. c Width W s Therefore, when the inner surface IF of the convex member CV is formed, it is formed so that it has the same shape as the inner surface design formed for each height.

[0118] Once a pair of short side portions 3120 including a convex member CV and a short side member 3121 are provided by this method, they are joined to a long side member 3111 to manufacture a mold. That is, as shown in FIG. 2, one end of each of the first and second short side members 3121 is connected to the inner surface of the first long side member 3111, and the other end of each of the first and second short side members 3121 is connected to the inner surface of the second long side member 3111. As a result, a mold is provided having an internal space IS surrounded by the inner surfaces IF of the convex members CV provided on the first and second short side members and the inner surfaces IF of the first and second long side members 3111.

[0119] At this time, the inner surface IF of the short side portion 3120, that is, the both side regions A of the inner surface IF of the convex member CV s The inner surface of the first side region A is in the shape of a cosine curve. s1 The inner surface of the second side region A is formed in the shape of a 0° to 180° section of one period of a cosine curve. s2 The inner surface of the side region A is formed in the shape of a 180° to 360° section of one cycle of a cosine curve. sThe angle θ between the inner surface IF of the widthwise edge of the protruding member CV and the inner surface IF of the long-side member 3111 is 90° or a right angle. In other words, the angle θ between the inner surface IF of the widthwise edge of the protruding member CV and the inner surface IF of the widthwise edge of the long-side member 3111 is 90° or a right angle. In this way, the angle θ between the inner surface IF of the widthwise edge of the protruding member CV and the inner surface of the widthwise edge of the long-side member 3111 is 90°, which means that the space between the inner surface IF of the widthwise edge of the protruding member CV and the inner surface of the widthwise edge of the long-side member 3111 is wider than when the angle θ is an acute angle (less than 90°).

[0120] Therefore, when molten steel is solidified inside the mold 3000 to cast the slab 1, it is possible to suppress or prevent the molten steel or solidified shell from being trapped in the space between the inner surface IF of the widthwise edge of the convex member CV and the inner surface IF of the widthwise edge of the long side member 3111. This prevents the occurrence of operational accidents in which the molten steel leaks out of the mold 3000 due to fracture of the slab 1. Furthermore, by providing the convex member CV on the inner surface IF of the short side member 3121, it is possible to prevent the occurrence of wrinkle defects or edge seam defects on the widthwise edge of the steel sheet 2 when the slab 1 is rolled to produce the steel sheet 2. In other words, by using the mold 3000 including the convex member CV provided by the method according to the embodiment, it is possible to produce a slab in which the occurrence of edge seam defects on the steel sheet 2 is suppressed, and it is also possible to prevent operational accidents due to the leakage of molten steel.

[0121] FIG. 10 shows a cast piece produced using a mold according to an embodiment of the present invention.

[0122] Referring to Fig. 10, both surfaces in the width direction of the slab 1 are formed in a concave shape recessed inward. In this case, each of the both surfaces has a curved surface in the shape of half of a cosine curve with one period of 360°. In other words, each of the both surfaces has a curved surface in the shape of half a period of a cosine curve with one period of 360°. More specifically, each of the both surfaces has a curved surface in the shape of a central surface F c and the central surface F cA pair of side surfaces F located on one side and the other side of s1 , F S2 , and a pair of side surfaces F s1 , F S2 Each of the central surface F has a curved surface that is half the shape of a cosine curve with one period of 360°. c may be in the shape of a plane, and a pair of side surfaces F s is the central surface F c That is, the pair of side surfaces F s One of them has the shape of a 0° to 180° section of one cycle of a cosine curve, and the other has the shape of a 180° to 360° section of one cycle of a cosine curve.

[0123] By rolling such a slab 1 having concave surfaces on both sides, the amount of width spread due to rolling can be reduced compared to conventional methods. Therefore, the occurrence of edge seam defects in the steel sheet 2 due to the width spread of the slab 1 can be suppressed.

[0124] Table 1 shows the results of producing steel plates by rolling cast pieces produced using molds equipped with convex members according to the examples and comparative examples, and showing the width of the area where defects occurred at the edge of the steel plate in the width direction.

[0125] Here, the convex member according to the embodiment is manufactured by the method described in FIG. 9 and is manufactured as shown in FIGS. 2, 6, and 7. That is, it is a convex member having a central region whose protruding length is the same in the width direction and side regions whose shape extending in the width direction is a cosine curve. Furthermore, the protruding length of the central region in the convex member is a specific length within a range of 10 mm to 20 mm, and the width of the central region is 10% to 15% of the width of the short side members. Furthermore, in the mold equipped with the convex member according to the embodiment, the angle θ between the inner surface of the widthwise edge of the convex member and the inner surface of the widthwise edge of the long side members is 90°.

[0126] The convex member of the comparative example is a fan-shaped arc (circular arc), and the protruding length of the center of the convex member in the width direction is 5 mm. The shape of the inner surface of the convex member is not a cosine curve. In the mold equipped with the convex member of the comparative example, the angle between the inner surface of the edge of the convex member in the width direction and the inner surface of the edge of the long side member in the width direction is an acute angle of less than 90°.

[0127] In Table 1, steel grades 1 to 11 refer to different steel grades having different chemical compositions. All of steel grades 1 to 11 are steel grades for producing stainless steel sheets, and are steel grades with some chemical compositions that differ from one another.

[0128] For the experiment, molten steels of the first to eleventh steel types were poured into the molds according to the comparative example and the example to produce slabs, and the slabs thus produced were rolled under the same conditions to produce steel plates.

[0129] Next, the width of the region where wrinkle defects occurred at the edge in the width direction of the steel sheet was measured. At this time, wrinkles were searched for starting from the outermost edge in the width direction of the steel sheet toward the center, and the distance from the wrinkle located closest to the edge of the outermost edge to the wrinkle located farthest from the edge of the outermost edge was measured and defined as the "defect occurrence width."

[0130] [Table 1]

[0131] Referring to Table 1, it can be seen that the width of the flaws was reduced in the examples compared to the comparative examples.

[0132] In addition, while pouring molten steel into the mold according to the comparative example and casting a slab, an accident occurred in which the molten steel leaked out of the mold. However, while pouring molten steel into the mold according to the example and casting a slab, no accident occurred in which the molten steel leaked out of the mold.

[0133] As described above, when the mold 3000 including the convex member CV according to the embodiment solidifies molten steel therein to cast a slab 1, it is possible to suppress or prevent molten steel or a solidified shell from being trapped in the space between the inner surface IF of the widthwise edge of the convex member CV and the inner surface IF of the widthwise edge of the long side member 3111. This makes it possible to prevent operational accidents in which the molten steel leaks out of the mold 3000 due to fracture of the slab 1. It is also possible to produce a slab 1 that can suppress the occurrence of wrinkle defects or edge seam defects on the widthwise edge of the steel sheet 2. That is, it is possible to produce a slab that can suppress the occurrence of edge seam defects on the steel sheet 2, and it is also possible to prevent operational accidents due to the leakage of molten steel. [Industrial Applicability]

[0134] The mold according to the embodiment of the present invention can produce a cast slab that can suppress edge seam defects in the steel plate caused by width expansion when the cast slab is rolled into a steel plate. Furthermore, during the production of a cast slab by solidifying molten steel inside the mold, or when the width of the mold is variable, it can suppress or prevent steel or a solidified shell from being trapped in the space between the inner surface of the edge of the convex member and the inner surface of the long side member. This can prevent operational accidents in which the molten steel leaks out of the mold due to breakage of the cast slab. In other words, the mold according to the embodiment of the present invention can produce a cast slab that can suppress edge seam defects in the steel plate, and can also prevent operational accidents due to leaking molten steel.

Claims

1. A mold having an internal space into which molten steel can be poured, a body having the internal space; a protruding member formed to protrude from the body toward the internal space and extend in a width direction of the body; Equipped with the protruding member includes a pair of side regions located on one side and the other side of a center in a width direction, and each of the pair of side regions has a shape in which a protruding length decreases with increasing distance from the center, The mold has inner surfaces of the pair of side regions each having a curved surface shaped like half of a cosine curve with one cycle of 360°.

2. the convex member includes a central region located between the pair of side regions, The protruding length of the central region is uniform in the width direction, The mold according to claim 1 , wherein an inner surface of the central region that faces the internal space has a shape having a flat surface.

3. The mold of claim 2 , wherein the pair of side regions are symmetrical in shape relative to the central region.

4. one of the pair of side regions has an inner surface shaped like a 0° to 180° section of one period of a cosine curve; 4. The mold according to claim 3, wherein the other has an inner surface shaped in the 180° to 360° section of one period of a cosine curve.

5. The body is a pair of long-side members each extending in one direction and arranged to face 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; Equipped with The mold according to claim 4 , wherein the convex member is formed so as to protrude from the short-side member toward the internal space.

6. 6. The mold according to claim 5, wherein an angle formed between the inner surface of the long side member and an edge of the inner surface of the side region is 90 degrees.

7. The mold according to claim 2 , wherein the protruding length of the central region of the convex member exceeds 5 mm.

8. The width of the convex member is equal to the width of the short side member, 6. The mold according to claim 5, wherein the width of the central region of the convex member is 10% to 15% of the width of the short side member.

9. The width of the short side members and the convex members decreases as they go downward, The mold according to claim 8 , wherein the width of the central region of the convex member is equal in the vertical direction.

10. The width of the short side members and the convex members decreases as they go downward, The mold of claim 8 , wherein the width of the central region of the convex member decreases as it progresses downward.

11. The mold according to claim 5 , wherein the vertical length of the convex member is the same as the vertical length of the short side member.

12. A method for manufacturing a casting mold including a body having an internal space and a protruding member formed to protrude from the body toward the internal space, a step of preparing a design plan for the convex member to include first and second side regions whose protruding lengths decrease as they move toward both ends of the center in the width direction, and for the inner surfaces of the first and second side regions to have a curved surface in the shape of half a cosine curve with one period of 360°; a step of processing a base material into a shape of a convex member included in the design proposal; A method for manufacturing a mold, comprising:

13. The process of creating the design plan includes: Width of the body to be manufactured (W ｍ ) and the vertical length (H ｍ ) and providing a design on the inner surface of the convex member including shapes for the inner surfaces of the first and second side regions; The method for producing the mold of claim 12, comprising:

14. The step of providing a design on the inner surface of the convex member includes: The protrusion length (T ｃ ) and width (W ｃ ) and The determined body width (W ｍ ), the determined protrusion length of the central region of the convex member (T ｃ ) and width (W ｃ ) to provide a design for the first side region such that the shape of the inner surface of the first side region is half the shape of a one-period cosine curve; The method for producing the mold of claim 13, comprising:

15. providing a design for the first side region; The determined body width (W ｍ ) and the width (W ｃ ) to determine the width (W) for the first side region to be produced. ｓ ) and The determined width (W ｓ ), the determined protrusion length of the central region (T ｃ ), a position in the width direction of the convex member (X), and a position in the thickness direction of the convex member (Y); calculating a position (Y) in the thickness direction according to the position (X) in the width direction using the cosine curve equation; Including, The value of the widthwise position (X) applied to the cosine curve equation is determined based on the determined body width (W ｍ ) from one end of the determined width (W ｓ 15. The method for manufacturing a mold according to claim 14, wherein the value is an interval from the point of the first dimension to a point that is separated by an amount corresponding to the distance between the first dimension and the second dimension, and a plurality of values are applied within the interval.

16. providing a design for the first side region; 16. The method for manufacturing a mold according to claim 15, further comprising the step of generating a design line for the first side region having a shape of half a cosine curve of one period by connecting a plurality of thickness direction positions (Y) calculated for each width direction position (X).

17. The step of providing a design on the inner surface of the convex member includes: providing a design for a central region, the design relating to an inner surface of the central region located between the first and second side regions; providing a design for the central region, The width (W) of the center region determined from the end of the design line for the first side region ｃ 17. The method of claim 16, further comprising extending the lines by an amount commensurate with the distance from the center of the mold to create the design lines for the center region.

18. providing a design for the second side region such that the shape of the inner surface of the second side region is half the shape of a one-period cosine curve; providing a design for the second side region; The method for manufacturing a mold according to claim 17, further comprising forming a design line for a second side region symmetrically with respect to the design line for the first side region, with the central region as a center.

19. The width of the body (W ｍ ), and the length in the thickness direction intersecting with the width direction is the determined protrusion length (T ｃ ) a base material having a thickness exceeding 100 nm; The process of processing the base material includes: On one of the surfaces in the thickness direction of the base material, the width (W ｓ 20. The method of claim 18, further comprising the step of processing the first and second side regions so that the shape of the first and second side regions is the design line up to a point away by an amount corresponding to the length of the first and second side regions.

20. A cast piece produced by solidifying molten steel, Both surfaces of the cast piece are inwardly concave; A cast slab, wherein a portion of each of the two surfaces has a curved surface in the shape of half of a cosine curve with one period of 360°.

21. Each of the two surfaces includes a central surface and a pair of side surfaces located on one side and the other side of the central surface, respectively; each of the pair of side surfaces has a curved surface having a shape of half a cosine curve with one cycle of 360°; 21. The cast piece of claim 20, wherein the central surface has a flat surface.

22. the pair of side surfaces are symmetrical with respect to the central surface; one of the pair of side surfaces has a shape of one period of a cosine curve in a 0° to 180° section; The cast piece according to claim 21, wherein the other has a shape of a 180° to 360° section of one period of a cosine curve.

Images