Twin roll casting apparatus and method for producing light metal plate

Abstract

To provide a twin roll type casting apparatus and a method of manufacturing a light metal plate capable of solving a problem of vertical burrs with a simpler method than the conventional technique.SOLUTION: A twin roll type casting apparatus for manufacturing a light metal plate includes two rollers, two side dam plates, two front dam plates and a metal pool. On the side dam plates, burr conversion plates having a predetermined thickness are provided, bottom surfaces of the burr conversion plates have lower end parts for connecting lower ends of two circular arcuate curved surfaces which are respectively abutted onto the surfaces of two rollers and two circular arcuate curved surfaces to each other, a height of the lower end part of the burr conversion plate is located on the lower side than a position on which two semi-solidified metal layers formed by two rollers are brought into first contact, and on the upper side than a kissing point of two rollers, and a thickness of the burr conversion plate is set so that an extension part formed by the semi-solidified metal layer flowing-out from the lower end part of the burr conversion plate to the outer side does not protrude from both end surfaces of the rollers.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a twin roll casting apparatus for producing light metal strip and a method for producing light metal strip. [Background technology]

[0002] The direct chill casting (DC) method has traditionally been used to manufacture aluminum sheets, but the continuous casting and rolling (CC) method, which realizes reduced manufacturing costs, is also becoming more widespread. CC casting is relatively rarely used in Japan because it is considered to have some issues with appearance quality, but it has become an alternative manufacturing method to DC casting overseas.

[0003] The belt method and twin roll method are known as the leading CC casting methods, and the belt method is suitable for manufacturing relatively thick plates of 10 to 40 mm, and is known to require large capital investment and high production capacity. The twin roll method is suitable for manufacturing thin plates of 3 to 10 mm, and is known to allow optimal investment according to market size with relatively low investment costs, and these manufacturing methods are selected depending on the conditions of the metal alloy plate to be manufactured.

[0004] In the high-speed twin roll process using a side dam plate, unsolidified metal material gets between the side of the roll and the side dam plate, which causes burrs perpendicular to the surface of the sheet (vertical burrs) on both ends of the metal alloy sheet. This has a known problem and has adverse effects on the coiling and cold rolling processes in the subsequent manufacturing process of the metal alloy sheet. Various measures have been taken to solve the problem of vertical burrs.

[0005] As a continuous casting method for solving the conventional problem of vertical burrs, for example, Patent Document 1 discloses a continuous casting method using a twin-roll type continuous caster in which the lower end of the side seal is placed below the lowest end of the unsolidified part to prevent the generation of burrs, while detecting deformation of the side seal due to lateral expansion caused by rolling and optimally controlling the height of the lower end of the side seal. The method of Patent Document 1 requires the control of the side seal using a position detector, a cylinder, etc.

[0006] Additionally, Patent Document 2 discloses an improved twin-roll continuous casting method and apparatus for controlling the operational position of a side dam in twin-roll continuous casting, in which the operational position (height) of the side dam is constantly controlled in accordance with fluctuations in the protrusion start position (height) during casting, thereby ensuring the sealing effect of the side dam and fully preventing the occurrence of pullouts and burrs, thereby enabling the stable production of slabs with good plate shapes. However, this method and apparatus uses a detection device that performs continuous detection during casting, which has a complex structure and requires fine control. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 59-215255 [Patent Document 2] Japanese Patent Application Publication No. 6-15414 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a twin-roll casting apparatus and a method for producing a light metal plate, which can solve the problem of vertical burrs in a simpler manner than the prior art. [Means for solving the problem]

[0009] The twin roll casting apparatus for producing light metal plate of the present invention comprises two cooling rolls arranged to have parallel rotation axes at a predetermined interval, two side dam plates abutting both end faces of the rolls and arranged to face each other, two front dam plates located on the surfaces of the rolls respectively and arranged to face each other, and a metal pool surrounded by the two side dam plates and the two front dam plates and formed on the surfaces of the two rolls and into which molten metal is supplied, and a burr conversion plate having a predetermined thickness is provided on each of the opposing surfaces of the two side dam plates, The bottom surface of the conversion plate has two arc-shaped curved surfaces that abut against the surfaces of the two rolls, respectively, and a lower end portion that connects the lower ends of the two arc-shaped curved surfaces to each other, and the height of the lower end portion of the burr conversion plate is located below the position where the molten metal in the metal pool is cooled by the two rolls and the two semi-solidified metal layers formed by the two rolls begin to contact each other, and above the kissing point of the two rolls, and the thickness of the burr conversion plate is set so that the extension portion formed by the semi-solidified metal layer flowing outward from the lower end portion of the burr conversion plate does not protrude outward from both end faces of the rolls.

[0010] The method for manufacturing a light metal plate of the present invention includes a process of using a twin-roll casting apparatus to supply molten metal to a metal pool and rotate the rolls to cool the molten metal, and a process of solidifying the molten metal by the two rolls to form a light metal plate, and is characterized in that during the process of forming the light metal plate, the semi-solidified metal layer flowing outward from the lower end of the burr conversion plate is adjusted by the burr conversion plate to an amount that does not protrude outward from both end faces of the roll, and extensions are formed on both sides of the light metal plate.

[0011] The light metal plate and the extension formed by the twin roll casting apparatus are annealed and cold rolled to form the extension as a part of the light metal plate. Effect of the Invention

[0012] The twin roll casting apparatus for producing light metal plate of the present invention comprises two cooling rolls arranged to have parallel rotation axes at a predetermined distance, two side dam plates abutting both end faces of the rolls and arranged to face each other, two front dam plates located on the surfaces of the rolls respectively and arranged to face each other, and a metal pool surrounded by the two side dam plates and the two front dam plates and formed on the surfaces of the two rolls to which molten metal is supplied, the metal pool having a predetermined thickness and a burr conversion plate on each of the opposing surfaces of the two side dam plates, the bottom surface of the burr conversion plate having two arc-shaped curved surfaces abutting the surfaces of the two rolls respectively, and a metal pool having a predetermined thickness and a burr conversion plate on each of the opposing surfaces of the two side dam plates ... and a lower end portion of the burr conversion plate is located below the position where the molten metal in the metal pool is cooled by the two rolls and the two semi-solidified metal layers formed by the two rolls begin to contact each other, and above the kissing point of the two rolls. The thickness of the burr conversion plate is set so that the extension portion formed by the semi-solidified metal layer flowing outward from the lower end portion of the burr conversion plate does not protrude outward from both end faces of the roll. Therefore, by simply using the burr conversion plate, the vertical burrs that have conventionally occurred can be easily converted into extension portions on both sides of the light metal plate, and the problems caused by conventional vertical burrs can be solved with a structure simpler than that of conventional devices, and further, damage to the side dam plate can be prevented and durability can be improved.

[0013] The method for manufacturing a light metal plate of the present invention includes a process of using a twin-roll casting apparatus to supply molten metal to a metal pool and rotate the rolls to cool the molten metal, and a process of solidifying the molten metal by the two rolls to form a light metal plate, and during the process of forming the light metal plate, the semi-solidified metal layer flowing outward from the lower end of the burr conversion plate is guided by the burr conversion plate so that it does not protrude outward from both end faces of the roll, and extensions are formed on both sides of the light metal plate.By simply using the burr conversion plate, the vertical burrs that previously occurred can be easily converted into extensions of the light metal plate, so that the problems caused by conventional vertical burrs can be solved in a simpler manner than before.

[0014] By annealing and cold rolling the light metal plate and the extension formed by the twin-roll casting apparatus to form the extension as part of the light metal plate, the extension can be utilized as part of the light metal plate rather than being disposed of as an unnecessary part, thereby improving the yield in the production of light metal plates. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of the twin-roll casting apparatus of the present invention, where (a) is a perspective view of the entire twin-roll casting apparatus, and (b) is a perspective view of the twin-roll casting apparatus with some components (a side dam plate and a front dam plate) omitted. [Diagram 2] FIG. 1 is a side view of the twin roll casting apparatus with the front side dam plate omitted. [Diagram 3] FIG. 13 is a perspective view of a burr conversion plate. [Figure 4] FIG. 2 is a central cross-sectional view of the twin roll casting apparatus during the formation of a light metal plate. [Diagram 5] 5 is a cross-sectional view of FIG. 4 taken along line aa. [Figure 6] 5 is a cross-sectional view taken along line bb in FIG. [Figure 7] FIG. 5 is a bottom view of the twin roll casting apparatus of FIG. [Figure 8] 3 is a photograph of a plane and a cross section of a light metal plate formed in an embodiment. [Figure 9] 1 is a photograph of a cross section of a light metal plate produced by a twin-roll casting apparatus. [Figure 10] 1 is a photograph of a cross section of the light metal plate and extension after annealing. [Figure 11] 1 is a photograph of a cross section of the light metal plate and extension after annealing and subsequent cold rolling. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The twin-roll casting apparatus 1 of the present invention and the method for producing a light metal sheet 10 will be described in detail below with reference to the drawings. First, the twin-roll casting apparatus 1 for producing a light metal sheet of the present invention will be described. Figure 1(a) shows a perspective view of the twin-roll casting apparatus 1 of the present invention, and Figure 1(b) shows a perspective view of the twin-roll casting apparatus 1 with the side dam plate 3 and front dam plate 4 located in the foreground omitted.

[0017] The twin-roll casting apparatus 1 of the present invention is an apparatus for manufacturing a light metal sheet 10, and the light metal sheet 10 is an aluminum sheet, an aluminum alloy sheet, a magnesium sheet, or a magnesium alloy sheet. The twin-roll casting apparatus 1 of the present invention includes two cooling rolls 2 arranged at a predetermined interval to have parallel rotation axes, two side dam plates 3 arranged to abut both end faces of the rolls 2 and to face each other, two front dam plates 4 located on the respective surfaces of the rolls 2 and to face each other, and a metal pool 5 to which a molten metal 11 of a light metal material (aluminum, aluminum alloy, magnesium, magnesium alloy) is supplied, and burr conversion plates 6 having a predetermined thickness t are provided on the opposing surfaces of the side dam plates 3.

[0018] The two rolls 2 are arranged at a predetermined interval according to the thickness of the light metal plate 10 to be manufactured, have the same length and the same outer diameter, and rotate in opposite directions to each other to cool and solidify the molten metal 11 in the metal pool 5, and form the light metal plate 10 while applying pressure and extending it downward. The interval between the two rolls 2 can be adjusted according to the thickness of the light metal plate 10 to be manufactured, and the rotation speed can also be adjusted according to the plate thickness, material, etc., and can be configured to be controlled by a separate control device. The configuration of the two rolls 2 can be the same as that of a conventional twin-roll casting device. The metal pool 5 is a space surrounded by the two side dam plates 3 and the two front dam plates 4 and formed on the surfaces of the two rolls 2, and the molten metal 11 of the light metal material is supplied by a trough or the like (not shown).

[0019] The side dam plate 3 is disposed so that its lower end is located at a kiss point B (a line connecting the center points of the two rolls 2) with respect to both end faces of the two rolls 2, and a heat insulating sheet made of alumina fiber or the like is provided on the opposing faces of the side dam plate 3 in a portion that contacts the molten metal 11 of the light metal material, and is disposed so as to abut against the end faces of the two rolls 2 or to leave a small gap. The material of the side dam plate 3 may be a mild steel plate or the like, but is not particularly limited. The opposing faces of the side dam plate 3 and both end faces of the two front dam plates 4 are connected to each other, and the metal pool 5 having a rectangular planar shape is formed on the surface of the two rolls 2. The opposing faces of the front dam plate 4 are provided with a heat insulating sheet made of alumina fiber or the like, similar to the side dam plate 3, and the same material as the side dam plate 3 can be used for the material.

[0020] The burr conversion plate 6 is fixed to the opposing surfaces of the side dam plate 3, has a predetermined thickness t, and is used to convert vertical burrs generated in a conventional twin-roll casting apparatus into an extension of a light metal plate. The burr conversion plate 6 has a width that can be accommodated between the two front dam plates 4, and the bottom surface has two arc-shaped curved surfaces 61 that abut against the surfaces of the two rolls, respectively, and a lower end portion 62 that connects the lower ends of the two arc-shaped curved surfaces 61 to each other, as shown in Figures 2 and 3. The opposing surfaces of the burr conversion plate 6 are provided with heat insulating sheets made of alumina fiber or the like, as with the side dam plate 3. The material of the burr conversion plate 6 can be the same as that of the side dam plate 3. The burr conversion plate 6 can also be formed integrally with the side dam plate 3, and in this case, a heat insulating sheet is provided to cover the surfaces of the integrally formed burr conversion plate 6 and the side dam plate 3 that contact the molten metal 11.

[0021] As shown in Fig. 5, the height of the lower end 62 of the burr conversion plate 6 is located below a position A where the molten metal 11 in the metal pool 5 is cooled by the two rolls 2 and the two semi-solidified metal layers 12 formed by the two rolls 2 start to contact each other, and above a kiss point B of the two rolls 2. As shown in Fig. 4, the thickness t of the burr conversion plate 6 is set so that the extensions 14 formed by the semi-solidified metal layers 12 flowing outward from the lower end 62 of the burr conversion plate 6 do not protrude outward from both end faces of the roll 2. As a result, the burr conversion plate 6 can convert the vertical burrs that were previously generated into extensions of the light metal plate.

[0022] It is also possible to create the twin-roll casting apparatus 1 of the present invention by modifying the structure of a conventional twin-roll casting apparatus to newly provide a burr conversion plate 6. In this case, the thickness of the burr conversion plate 6 and the height of the lower end 62 must be appropriately set so as to form only the extension 14.

[0023] Next, a method for manufacturing a light metal plate of the present invention will be described. First, in the twin-roll casting apparatus 1, the rolls 2 are rotated in opposite directions, and a molten metal 11 made of a light metal material is supplied to a metal pool 5 by a trough or the like. The light metal material is aluminum, an aluminum alloy, magnesium, or a magnesium alloy. Then, by rotating the rolls 2 in opposite directions, the molten metal 11 is cooled and solidified by the rolls 2 to form a semi-solidified metal layer 12, which is further solidified to form a solidified metal layer 13, and the state in which the semi-solidified metal layer 12 and the solidified metal layer 13 are formed on the surface of the rolls 2 is maintained as shown in FIG. Then, the solidified metal layer 13 is pressed by the two rolls 2 and pushed downward to form a light metal plate 10.

[0024] At this time, as shown in Fig. 4, most of the semi-solidified metal layer 12 is solidified into the solidified metal layer 13, but the semi-solidified metal layer 12 near the burr conversion plate 6 protrudes outward from the lower end 62 of the burr conversion plate 6. At this time, as shown in Fig. 4, the amount of the semi-solidified metal layer 12 protruding from the lower end 62 of the burr conversion plate 6 is within the range of the thickness t of the burr conversion plate 6, so that an extension 14 having the same thickness as the light metal plate 10 is formed from the semi-solidified metal layer 12 protruding from the lower end 62 of the burr conversion plate 6 by the two rolls 2 as shown in Fig. 6. If the thickness t of the burr conversion plate 6 is thin, the semi-solidified metal layer 12 protruding outward from the lower end 62 of the burr conversion plate 6 will further protrude outward from the gap between the side dam plate 3 and both end faces of the roll 2 and solidify, resulting in the generation of vertical burrs as in the conventional method. Therefore, in the twin-roll casting apparatus 1 of the present invention, the thickness t of the burr conversion plate 6 is set so that the semi-solidified metal layer 12 protruding outward from the lower end 62 of the burr conversion plate 6 does not protrude from both end faces of the roll 2.

[0025] Furthermore, as shown in FIG. 5 , the height of the lower end 62 of the burr conversion plate 6 is located below the position A where the two semi-solid metal layers 12 formed by the two rolls 2 start to contact each other, and above the kiss point B of the two rolls 2.

[0026] In the twin-roll casting apparatus 1 of the present invention, the side dam plate 3 is provided with a burr conversion plate 6, and the thickness and height of the lower end of the burr conversion plate 6 are specified, so that the vertical burrs that have conventionally occurred can be converted into the extensions 14. Thus, the problems caused by the conventional vertical burrs can be easily solved by simply preparing the appropriate burr conversion plate 6. Furthermore, in the twin-roll casting apparatus 1 of the present invention, the semi-solidified metal pushed in the roll axial direction is pushed out from the lower end 62 of the burr conversion plate 6 to the outer lower part, and the amount of the semi-solidified metal pushed out is adjusted so that it does not protrude from both end faces of the roll 2, so that the heat insulating sheet on the surface of the side dam plate 3 is not damaged by the extensions 14, and therefore the durability of the side dam plate 3 can be improved. Furthermore, the semi-solidified metal is pushed out from the lower end 62 of the burr conversion plate 6, which serves to reduce the force acting in the roll axial direction, and damage to the side dam plate 6 can be prevented.

[0027] Aluminum, an aluminum alloy, magnesium, or a magnesium alloy is used as a material for manufacturing the light metal plate 10. In addition, conditions such as the rotation speed of the roll 2 and the temperature of the molten metal 11 can be appropriately adjusted depending on the material, plate thickness, etc.

[0028] In the method for manufacturing a light metal plate of the present invention, after forming the light metal plate 10 by the twin-roll casting apparatus 1, the light metal plate 10 and the extension portion 14 can be further annealed and cold rolled. By performing annealing and cold rolling, the extension portion 14 can be processed into a part of the light metal plate 10. FIG. 9 shows a photograph of a cross section of the light metal plate 10 in a state in which the extension portion 14 is formed on the right side of the light metal plate 10. After this, when annealing is performed, as shown in the photograph of FIG. 10, it can be seen that the extension portion 14 approaches the same state as the light metal plate 10. Furthermore, when cold rolling is performed, as shown in the photograph of FIG. 11, it can be seen that the extension portion 14 is processed into the same state as the light metal plate 10. In this way, the manufacturing method for a light metal plate of the present invention can improve the yield by performing annealing and cold rolling to process a part of the extension portion 14 into the light metal plate 10.

[0029] Next, the twin-roll casting apparatus 1 and the method for manufacturing a light metal plate of the present invention will be described using examples. In the following examples, a light metal plate is manufactured in the twin-roll casting apparatus 1 by providing a burr conversion plate 6 on only one of the two side dam plates 3 and not providing a burr conversion plate 6 on the other side dam plate 3. This makes it possible to compare the results of the examples with those of the conventional method in which no burr conversion plate 6 is used, by simply manufacturing one light metal plate.

[0030] The twin-roll casting apparatus 1 used in the examples used side dam plates 3 and front dam plates 4 made of 3.2 mm thick mild steel plates with a 2 mm thick heat insulating sheet attached, one of the side dam plates 3 was provided with a burr conversion plate 6 made of 10 mm thick mild steel plate, and the other side dam plate 3 was used alone without a burr conversion plate 6. The two rolls 2 were copper rolls with a diameter of 300 mm and a width of 50 mm.

[0031] ADC12 was used as the material, and the molten metal temperature was 610°C. The roll 2 had two roll circumferential speeds of 30 m / min and 60 m / min. The solidification distance was 100 mm, and the roll load was 80 N / mm. The distance Dbs from the kiss point B to the lower end 62 of the burr conversion plate 6 was three, 15 mm, 25 mm, and 30 mm. A total of six aluminum alloy plates were formed under the above conditions.

[0032] Figure 8 shows the plan and cross-sectional photographs of the six aluminum alloy plates obtained, where the left side of each aluminum alloy plate is the edge where the burr conversion plate 6 is provided (Example of the present invention), and the right side is the edge where the burr conversion plate 6 is not provided (Comparative example of the prior art). Referring to Figure 8, when the roll peripheral speed is 30 m / min, when Dbs is 15 mm and 25 mm, no vertical burrs are generated on the left edge where the burr conversion plate 6 is provided (Example of the present invention), and vertical burrs are generated on the right edge where the burr conversion plate 6 is not provided (Comparative example of the prior art), so it can be seen that the vertical burrs are converted into extensions by the burr conversion plate 6. When Dbs is 30 mm, vertical burrs are generated not only on the right edge where the burr conversion plate 6 is not provided, but also on the left edge where the burr conversion plate 6 is provided, so it can be seen that the height of the burr conversion plate 6 was not appropriate. That is, in the case of a roll peripheral speed of 30 m / min, when the height of the lower end 62 of the burr conversion plate 6 is 30 mm from the kiss point B, it is considered that the height is above the position where the two semi-solidified metal layers formed by the two rolls 2 start to contact each other. Therefore, in the case of a roll peripheral speed of 30 m / min, in order to make the height of the lower end 62 of the burr conversion plate 6 below the position where the two semi-solidified metal layers formed by the two rolls 2 start to contact each other, it is necessary to make the height 25 mm or less from the kiss point B.

[0033] 8, when the roll peripheral speed is 60 m / min and Dbs is 15 mm, 25 mm, and 30 mm, no vertical burrs are generated on the left edge (embodiment of the present invention) where the burr conversion plate 6 is provided, and vertical burrs are generated on the right edge where the burr conversion plate 6 is not provided, so that in the embodiment of the present invention, the vertical burrs are converted into extensions by the burr conversion plate 6. In other words, when the roll peripheral speed is 60 m / min, it is found that the height of the lower end 62 of the burr conversion plate 6 should be set to 30 mm or less from the kiss point B in order to be lower than the position where the two semi-solid metal layers formed by the two rolls 2 start to contact each other.

[0034] From the above examples, it can be seen that the twin roll casting apparatus 1 of the present invention is able to convert vertical burrs into extensions by providing the burr conversion plate 6. Furthermore, in the twin roll casting apparatus 1 used in the examples, the heat insulating sheet of the side dam plate 3 on the side where the burr conversion plate 6 was not provided was damaged by vertical burrs, whereas the heat insulating sheet of the side dam plate 3 on the side where the burr conversion plate 6 was provided was not damaged because no vertical burrs were formed. This shows that providing the burr conversion plate 6 has the effect of improving the durability of the side dam plate 3.

[0035] The twin-roll casting apparatus 1 of the present invention is provided with a burr conversion plate 6 on the side dam plate 3, which makes it possible to convert vertical burrs into extensions, thereby eliminating the problems caused by conventional vertical burrs and improving the durability of the side dam plate 3. Furthermore, because extensions are formed on both sides of the light metal plate by the twin-roll casting apparatus 1 of the present invention, if annealing and cold rolling are performed, part of the extensions can be used as the light metal plate, improving the yield.

[0036] From the examples, it can be seen that the position where the two semi-solid metal layers formed by the two rolls 2 start to contact each other also changes depending on the roll circumferential speed, so when setting the height of the lower end 62 of the burr conversion plate 6, the roll circumferential speed must also be taken into consideration. By preparing a plurality of burr conversion plates 6 with different thicknesses t and lower end heights based on various conditions, it becomes possible to select an appropriate burr conversion plate 6 according to the conditions of the light metal plate to be manufactured, thereby further improving convenience. [Explanation of symbols]

[0037] 1 Twin roll casting equipment 2 rolls 3 Side Dam Plate 4 Front Dam Plate 5 Metal Pool 6 Burr conversion plate 61 Circular curved surface 62 Lower end 10 Light metal plate 11 Molten metal 12 Semi-solid metal layer 13 Solidified metal layer 14 Extension A: The position where the semi-solid metal layers start to contact each other. B kiss point

Claims

1. A twin roll casting apparatus for producing light metal plates, comprising: Two cooling rolls arranged with parallel rotation axes at a predetermined distance from each other; Two side dam plates arranged to abut against both end surfaces of the roll and to face each other; Two front dam plates located on the respective surfaces of the rolls and arranged to face each other; and a metal pool surrounded by the two side dam plates and the two front dam plates and formed on the surfaces of the two rolls, and into which molten metal is supplied; A burr conversion plate having a predetermined thickness is provided on each of the opposing surfaces of the two side dam plates, The bottom surface of the burr conversion plate has two arcuate curved surfaces that respectively abut against the surfaces of the two rolls, and a lower end portion that connects the lower ends of the two arcuate curved surfaces to each other, a height of the lower end of the burr conversion plate is located below a position where the molten metal in the metal pool is cooled by the two rolls and two semi-solidified metal layers having fluidity formed by the two rolls start to contact each other, and above a kiss point of the two rolls, so that vertical burrs are not generated; a thickness of the burr conversion plate being set so that an extension portion formed by the semi-solidified metal layer flowing out from the lower end of the burr conversion plate toward the side dam plate on which the burr conversion plate is provided does not protrude outside from both end faces of the roll.

2. 2. A process for supplying molten metal to the metal pool and rotating the rolls to cool the molten metal using the twin roll casting apparatus of claim 1; and The process includes solidifying the molten metal by the two rolls to form a light metal plate, A method for manufacturing a light metal plate, characterized in that, during a process of forming the light metal plate, the semi-solidified metal layer flowing out from the lower end of the burr conversion plate toward the side dam plate on which the burr conversion plate is provided is guided by the burr conversion plate so as not to protrude outward from both end faces of the roll, and extensions are formed on both sides of the light metal plate.

3. 3. The method for manufacturing a light metal plate according to claim 2, further comprising annealing and cold rolling the light metal plate and the extension formed by the twin-roll casting apparatus to form the extension as a part of the light metal plate.

Images