Pinch roll unit for thin cast slabs, thin cast slab manufacturing device, and thin cast slab manufacturing method

Abstract

To provide a pinch roll unit for a thin-walled slab capable of, even if a slab crown of a thin-walled slab changes in casting, maintaining the shape of the thin-walled slab constant and stabilizing casting while securing the controllability of meander with a pinch roll.SOLUTION: A pinch roll unit 40 for a thin-walled slab, for clamping a thin-walled slab 1 formed by continuous casting in a thickness direction and carrying the same, comprises: pinch rolls 41 for clamping the thin-walled slab 1; shape measuring means 43 that is provided further upstream in a transport direction F of the thin-walled slab 1 than the pinch rolls 41, for measuring the shape of the thin-walled slab 1 clamped by the pinch rolls 41; and pinch-roll deforming means 42 for deforming the pinch rolls 41. The pinch rolls 41 are deformed depending on the shape of the thin-walled slab 1 measured by the shape measuring means 43 so that the thin-walled slab 1 is clamped by the deformed pinch rolls 41.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pinch roll unit for thin slabs that clamps and transports thin slabs formed by continuous casting in the thickness direction, a thin slab manufacturing device that transports thin slabs using this pinch roll unit for thin slabs, and a method for manufacturing thin slabs. [Background technology]

[0002] As an apparatus for producing thin metal billets, there is provided a twin-roll continuous casting apparatus, as disclosed in Patent Documents 1 and 2, which is equipped with a pair of chill rolls having an internal water-cooling structure and rotating in opposite directions, in which molten metal is supplied to a molten metal pool formed by the pair of chill rolls and a pair of side weirs, solidified shells are formed and grown on the circumferential surfaces of the chill rolls, and the solidified shells formed on the circumferential surfaces of the pair of chill rolls are pressed together at a roll kiss point to produce thin billets of a predetermined thickness. Such twin-roll continuous casting apparatuses are applied to various metals.

[0003] In the twin-roll continuous casting apparatus described above, molten metal is continuously supplied to the molten metal pool from a tundish located above the chill rolls via an immersion nozzle. The molten metal solidifies and grows on the outer circumferential surfaces of the rotating chill rolls, forming solidified shells. The solidified shells formed on the outer circumferential surfaces of the chill rolls are then pressed together at the roll kiss points to produce thin-walled cast strips.

[0004] Patent Document 3 discloses a method and apparatus for manufacturing a thin cast slab, which is configured to include a magnetic field generator disposed above a tundish, maintaining the molten metal surface flowing in the direction of a pair of chill rolls disposed near the center of the molten metal surface in the tundish, bringing the molten metal into contact with the outer peripheral surfaces of the pair of chill rolls to grow a solidified shell, pressing the solidified shells together at the roll kiss points, and pulling the resulting thin cast slab upward.

[0005] The thin-walled cast strip continuously cast as described above is conveyed while being sandwiched in the thickness direction by pinch rolls. If the thin-walled cast strip meanders during transport, it may not be possible to transport the thin-walled cast strip stably, which may require the casting to be stopped.Furthermore, the thin-walled cast strip may not be rewound in a good shape by the winding device, which may require the thin-walled cast strip to be rewound. For this reason, various means have been proposed for controlling the meandering of the transported thin-walled cast strip, as shown in, for example, Patent Documents 4 to 7 below.

[0006] Patent Documents 4 to 6 propose a means for suppressing the meandering of thin-walled cast slabs by leveling them by applying a difference in load to both ends of the pinch rolls depending on the amount of meandering of the thin-walled cast slabs (the amount of offset from the conveying direction of the thin-walled cast slabs). Patent Document 7 proposes a means for suppressing meandering of thin-walled cast strips by shifting the parallelism of the rotation axes of pinch rolls. These meandering control technologies apply thrust force to the thin-walled slab by changing the widthwise distribution of the pinch roll pressure on the thin-walled slab, thereby guiding the slab in the opposite direction to the meandering direction and eliminating the meandering. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 02-092438 [Patent Document 2] Japanese Patent Application Publication No. 2017-087259 [Patent Document 3] Japanese Patent Publication No. 130750 / 1983 [Patent Document 4] Japanese Patent Application Publication No. 11-156504 [Patent Document 5] Japanese Patent Application Publication No. 08-206790 [Patent Document 6] Special Publication No. 2003-522024 [Patent Document 7] Japanese Patent Application Publication No. 08-215814 Summary of the Invention [Problem to be solved by the invention]

[0008] The cross-sectional shape of a thin-walled slab perpendicular to the casting direction is typically convex, with the thickness at the center and decreasing toward the width edges. The thickness curve from the width center to the width edges (hereinafter referred to as the slab crown) and the thickness difference can take on various values ​​depending on the width and thickness of the thin-walled slab, as well as its composition. Therefore, if the pinch roll barrel shape is designed based on a pre-determined shape of the slab crown, it becomes possible to precisely control the widthwise distribution of pressure, thereby enabling more stable and reliable control of meandering.

[0009] Here, in a thin-walled cast piece formed by continuous casting, the cast piece crown may change during casting. For example, in the early stages of casting, the mold (the cooling roll in a twin-roll continuous casting machine) is not sufficiently warmed, and as casting progresses and the mold gradually warms up, the mold's shape changes due to thermal expansion, which can cause a corresponding change in the crown of the cast piece. Furthermore, if the cast plate thickness is changed during casting, the mold heat flux changes, which in turn changes the amount of thermal expansion of the mold, which may result in a change in the crown of the cast piece.

[0010] In this way, if the crown shape of a thin-walled cast strip changes during casting, the widthwise distribution of the pressure changes from moment to moment when controlling meandering with pinch rolls, which could disrupt meandering control. The influence of the pinch roll on the change in the crown of the cast slab will be described in more detail below.

[0011] In the pinch rolls located closest to the mold, the temperature of the thin-walled cast strip is higher, and the thin-walled cast strip is brittle and easily deformed, so the following phenomenon occurs more significantly. First, if the barrel shape of the pinch rolls is set assuming the minimum value of the slab crown, when the slab crown reaches its maximum value, excessive pressure is applied to the widthwise center of the thin slab, making it difficult to apply thrust force to the thin slab, and thus deteriorating meandering controllability. Furthermore, if the pressure is excessively increased in order to control meandering, the widthwise center of the thin slab will be rolled, resulting in central elongation and a deterioration in shape. Conversely, if the barrel shape of the pinch rolls is set assuming the maximum value of the slab crown, excessive pressure will be applied to the widthwise ends of the thin slab when the slab crown is at its minimum value, causing the thin slab to elongate at the ends and generating ear waves, which will deteriorate the shape of the thin slab and have adverse effects on the transportability, meandering controllability, and coil winding ability after the pinch rolls.

[0012] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a pinch roll unit for thin slabs, an apparatus for manufacturing thin slabs, and a method for manufacturing thin slabs, which are capable of maintaining a constant shape of the thin slab and stabilizing casting while ensuring meandering controllability by the pinch rolls even if the slab crown of the thin slab changes during casting. [Means for solving the problem]

[0013] In order to solve the above-mentioned problems, the pinch roll unit for thin slabs according to the present invention is a pinch roll unit for thin slabs that sandwiches and transports thin slabs formed by continuous casting in a thickness direction, and includes pinch rolls that sandwich the thin slab, shape measuring means that is arranged upstream of the pinch rolls in the transport direction of the thin slab and that measures the shape of the thin slab sandwiched between the pinch rolls, and pinch roll deformation means that deforms the pinch rolls, and Crown To the shape To match The pinch roll is deformed, and the deformed pinch roll is used to cast the thin-walled slab. By suppressing deformation of It is characterized by clamping.

[0014] According to the pinch roll unit for thin cast slabs having the above-described configuration, a shape measuring means arranged upstream of the pinch rolls in the transport direction of the thin cast slab measures the shape of the thin cast slab clamped between the pinch rolls, and a pinch roll deformation means deforms the pinch rolls in accordance with the measured shape of the thin cast slab.Therefore, even if the crown of the thin cast slab changes during casting, the pinch rolls can be deformed in accordance with the changed crown shape of the thin cast slab. Therefore, a portion of the width of the thin-walled cast piece is not locally pressed strongly, the shape of the thin-walled cast piece can be kept constant, and meandering control can be stably performed by the pinch rolls, making it possible to transport the thin-walled cast piece stably.

[0015] Here, in the pinch roll unit for thin cast slabs of the present invention, it is preferable to provide a temperature measuring means that is arranged upstream of the pinch rolls in the transport direction of the thin cast slabs and that measures the temperature of the thin cast slabs clamped between the pinch rolls. In this case, the temperature of the thin-walled cast piece clamped between the pinch rolls can be measured, and the deformation amount and pressing force of the pinch rolls can be adjusted taking into account the strength of the thin-walled cast piece, thereby suppressing deformation of the thin-walled cast piece.

[0016] In the pinch roll unit for thin cast strips of the present invention, the pinch roll deforming means may be a backup roll arranged on the back side of the pinch roll. In this case, by bending the pinch rolls with the backup rolls, it becomes possible to deform the pinch rolls into a shape corresponding to the crown of the thin-walled cast slab, thereby enabling stable transport of the thin-walled cast slab.

[0017] In the pinch roll unit for thin cast strips of the present invention, the pinch roll deforming means may be an outer diameter adjusting means disposed inside the pinch roll. In this case, by adjusting the outer diameter of a portion of the pinch roll using the outer diameter adjusting means, it becomes possible to deform the pinch roll into a shape that corresponds to the cast crown of the thin-walled cast piece, making it possible to transport the thin-walled cast piece stably.

[0018] In addition, in the pinch roll unit for thin cast slabs of the present invention, a second shape measuring means for measuring the shape of the thin cast slab clamped between the pinch rolls may be arranged downstream of the pinch rolls in the transport direction of the thin cast slab. In this case, the shape of the thin-walled cast piece clamped between the pinch rolls is measured by a second shape measuring means, and the deformation amount and pressing force of the pinch rolls are adjusted according to the measurement results, thereby further suppressing deformation of the thin-walled cast piece.

[0019] In the pinch roll unit for thin cast strips of the present invention, meandering detection means for detecting the amount of meandering of the thin cast strip may be disposed upstream of the pinch rolls in the transport direction of the thin cast strip. In this case, the amount of meandering of the thin-walled cast strip can be detected by the meandering detection means, and meandering control by the pinch rolls can be carried out more stably.

[0020] The thin-walled cast slab manufacturing apparatus of the present invention comprises a continuous casting machine that continuously casts thin-walled cast slabs, and the above-mentioned pinch roll unit for thin-walled cast slabs, and is characterized in that the pinch roll unit for thin-walled cast slabs clamps and transports the thin-walled cast slabs formed by the continuous casting machine in the thickness direction. In the thin-walled cast slab manufacturing apparatus of this configuration, the thin-walled cast slab formed by the continuous casting machine is clamped in the thickness direction and transported by the aforementioned thin-walled cast slab pinch roll unit, which prevents the thin-walled cast slab from meandering and deforming, making it possible to produce high-quality thin-walled cast slabs with stable shapes.

[0021] Here, in the thin-walled cast slab manufacturing apparatus of the present invention, the continuous casting machine is preferably a twin-roll continuous casting machine that supplies molten metal to a molten metal pool formed by a pair of rotating chill rolls and a pair of side weirs, and forms and grows a solidified shell on the peripheral surface of the chill rolls to produce a thin-walled cast slab. In this case, it becomes possible to stably continuously cast thin-walled cast pieces.

[0022] The method for producing a thin cast slab according to the present invention is characterized in that a thin cast slab formed in a continuous casting machine is pinched in the thickness direction and conveyed by the above-mentioned pinch roll unit for a thin cast slab. In the thin-walled cast slab manufacturing method having this configuration, the thin-walled cast slab formed by the continuous casting machine is clamped in the thickness direction and transported by the above-mentioned pinch roll unit for the thin-walled cast slab, which makes it possible to suppress meandering of the thin-walled cast slab and deformation of the thin-walled cast slab, thereby making it possible to produce high-quality thin-walled cast slabs with stable shapes.

[0023] Here, in the method for producing a thin cast slab of the present invention, the continuous casting machine is preferably a twin-roll continuous casting machine that supplies molten metal to a molten metal pool formed by a pair of rotating chill rolls and a pair of side weirs, and produces a thin cast slab by forming and growing a solidified shell on the peripheral surface of the chill rolls. In this case, it becomes possible to stably continuously cast thin-walled cast pieces. [Effects of the Invention]

[0024] As described above, according to the present invention, it is possible to provide a pinch roll unit for thin slabs, an apparatus for manufacturing thin slabs, and a method for manufacturing thin slabs, which are capable of maintaining a constant shape of the thin slab and stabilizing casting while ensuring meandering controllability by the pinch rolls even if the slab crown of the thin slab changes during casting. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic explanatory diagram of a thin-walled cast slab manufacturing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective explanatory view of the thin-walled cast slab manufacturing apparatus shown in FIG. [Figure 3] FIG. 2 is an enlarged explanatory view of the periphery of a cooling roll of the thin-walled cast slab manufacturing apparatus shown in FIG. [Figure 4] FIG. 2 is an explanatory view of a cross-sectional shape of a thin-walled cast slab according to an embodiment of the present invention. [Figure 5] FIG. 1 is an explanatory diagram of a pinch roll unit for a thin cast strip according to an embodiment of the present invention. [Figure 6] This is an explanatory diagram of a pinch roll deformation means provided in the pinch roll unit for thin-walled cast slabs shown in Figure 5. (Nippon Steel Corporation, ed., "A Book to Understand Iron and Steel," Nippon Jitsugyo Publishing, November 10, 2004, p. 96) [Figure 7] FIG. 4 is an explanatory diagram of the amount of bending of a pinch roll. [Figure 8] FIG. 10 is an explanatory view of a pinch roll deformation means provided in a pinch roll unit for thin cast strips according to another embodiment of the present invention. [Figure 9] FIG. 10 is an explanatory diagram of flatness in an example. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, a pinch roll unit for thin cast slabs, an apparatus for manufacturing thin cast slabs, and a method for manufacturing thin cast slabs according to embodiments of the present invention will be described with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiments. In this embodiment, molten steel is used as the molten metal, and a thin cast 1 made of steel is produced. In this embodiment, the width of the produced thin cast 1 is within a range of 500 mm to 1500 mm, and the thickness is within a range of 1 mm to 5 mm.

[0027] As shown in Figures 1 and 2, the thin-walled cast slab manufacturing apparatus 10 of this embodiment includes a continuous casting machine 20 that continuously casts the thin-walled cast slab 1, and a conveying section 30 that conveys the thin-walled cast slab 1 formed by the continuous casting machine 20 in a conveying direction F. The conveying section 30 includes a pinch roll unit 40 for thin-walled cast slabs that clamps and conveys the thin-walled cast slabs 1 in the thickness direction, an in-line rolling mill 31, a looper 32, a coiler 33, and multiple guide rolls 34.

[0028] As shown in Figure 3, the continuous casting machine 20 is a twin-roll continuous casting machine equipped with a pair of cooling rolls 21, 21, side weirs 25 arranged at the widthwise ends of the pair of cooling rolls 21, 21, a tundish 28 that holds molten steel 3 to be supplied to a molten steel pool section 26 defined by the pair of cooling rolls 21, 21 and the side weir 25, and an immersion nozzle 29 that supplies molten steel 3 from the tundish 28 to the molten steel pool section 26.

[0029] In this continuous casting machine 20, the molten steel 3 comes into contact with the cooling rolls 21, 21 rotating in the rotation direction R and is cooled, causing solidified shells 5, 5 to grow on the peripheral surfaces of the cooling rolls 21, 21, and the solidified shells 5, 5 formed on the pair of cooling rolls 21, 21 are pressed together at the roll kiss points, thereby casting a thin-walled cast 1 of a predetermined thickness. In the conveying section 30, the formed thin billet 1 is conveyed horizontally by a pinch roll unit 40 for thin billet, rolled to a predetermined thickness by an in-line rolling mill 31, and wound up by a coiler 33.

[0030] The thin-walled slab 1 cast by the continuous casting machine 20 is usually thick at the width center and becomes thinner toward the width ends, exhibiting a convex shape, as shown in Fig. 4. The thickness curve (slab crown) from the width center to the width ends and the thickness difference can take various values ​​depending on the width and thickness of the thin-walled slab 1, or the composition of the thin-walled slab. Furthermore, the cross-sectional shape (slab crown) of the thin-walled cast slab 1 may change during casting depending on the casting conditions and the like.

[0031] Therefore, in the pinch roll unit 40 for thin slabs of this embodiment, which is arranged in the conveying section 30, as shown in Figures 2 and 5, it is equipped with pinch rolls 41, 41 that clamp the thin slab 1, a shape measuring means 43 that is arranged upstream of the pinch rolls 41, 41 in the conveying direction F of the thin slab 1 and measures the shape of the thin slab 1, and pinch roll deformation means 42, 42 that deform the pinch rolls 41, 41, and is configured to deform the pinch rolls 41, 41 according to the shape (slab crown) of the thin slab 1 measured by the shape measuring means 43, and to clamp the thin slab 1 in the thickness direction with the deformed pinch rolls 41, 41.

[0032] In this embodiment, as shown in Figures 2 and 5, a temperature measuring means 44 for measuring the temperature of the thin-walled cast 1 sandwiched between the pinch rolls 41, 41 is arranged upstream of the pinch rolls 41, 41 in the transport direction F of the thin-walled cast 1. In this embodiment, as shown in FIGS. 2 and 5, a meandering detection means 45 for detecting the amount of meandering of the thin cast slab 1 is disposed upstream of the pinch rolls 41, 41 in the transport direction F of the thin cast slab 1. Furthermore, in this embodiment, as shown in Figure 5, a second shape measuring means 46 for measuring the shape of the thin-walled cast 1 clamped between the pinch rolls 41, 41 is arranged downstream of the pinch rolls 41, 41 in the conveying direction F of the thin-walled cast 1.

[0033] Here, the shape measuring means 43 measures the shape of the transported thin-walled cast 1, and in this embodiment, is an X-ray transmission type thickness gauge extending in the width direction of the transported thin-walled cast 1. By measuring the thickness of the thin slab 1 in the width direction, it is possible to measure the cross-sectional shape (slab crown) of the thin slab 1. In addition, by extending the X-ray transmission type thickness gauge to the outside of the width direction end of the thin slab 1, it is possible to detect meandering of the thin slab 1. That is, in this embodiment, the shape measuring means 43 also functions as the meandering detection means 45.

[0034] In this embodiment, the pinch roll deformation means 42 is a backup roll arranged on the back side of the pinch roll 41. As shown in FIG. 6, the pinch roll deformation means 42 is configured to deform the pinch roll 41 by bending the pinch roll 41 with a backup roll. That is, in this embodiment, the amount of bending of the pinch rolls 41, 41 is adjusted by the backup rolls that are the pinch roll deformation means 42 in accordance with the shape of the thin-walled cast slab 1 (cast slab crown). Here, the bending amount is defined as the amount of deformation of the pinch rolls 41, 41 at the edge of the thin-walled cast slab 1 before and after bending, as shown in FIG.

[0035] In this embodiment, it is not necessary to deform the pinch roll 41 so as to completely match the crown of the thin-walled cast strip 1 . Here, the bending amount of the pinch roll 41 is preferably in the range of 10 μm to 150 μm when the width of the thin-walled cast slab 1 is in the range of 500 mm to 1500 mm and the thickness is in the range of 1 mm to 5 mm.

[0036] In addition, in this embodiment, as shown in Figures 2 and 5, a temperature measuring means 44 for measuring the temperature of the thin-walled cast 1 held between the pinch rolls 41, 41 is arranged upstream of the pinch rolls 41, 41 in the transport direction F of the thin-walled cast 1, and the deformation amount of the pinch rolls 41 and the pressing force of the pinch rolls 41, 41 are adjusted taking into account the strength of the thin-walled cast 1 held between the pinch rolls 41, 41.

[0037] In addition, in this embodiment, as shown in Figures 2 and 5, a meandering detection means 45 for detecting the amount of meandering of the thin cast slab 1 is arranged upstream of the pinch rolls 41, 41 in the transport direction F of the thin cast slab 1, and the meandering of the thin cast slab 1 is controlled by controlling the operation of the pinch rolls 41, 41 in accordance with the amount of meandering of the thin cast slab 1. The meandering control method may be, for example, leveling control of the pinch rolls 41, 41 or control of the cross angle of the pinch rolls.

[0038] Furthermore, in this embodiment, as shown in Figure 5, a second shape measuring means 46 for measuring the shape of the thin-walled cast 1 held between the pinch rolls 41, 41 is arranged downstream of the pinch rolls 41, 41 in the conveying direction F of the thin-walled cast 1. This second shape measuring means 46 measures the shape of the thin-walled cast 1 held between the pinch rolls 41, 41, and the measurement results are fed back to adjust the deformation amount and pressing force of the pinch rolls 41, 41.

[0039] In the pinch roll unit 40 for thin slabs of this embodiment, which is configured as described above, a shape measuring means 43 arranged upstream of the pinch rolls 41, 41 in the transport direction F of the thin slab 1 measures the shape (slab crown) of the thin slab 1 clamped between the pinch rolls 41, 41, and a pinch roll deformation means 42 deforms the pinch rolls 41, 41 according to the measured shape of the thin slab 1.Therefore, even if the slab crown of the thin slab 1 changes during casting, the pinch roll 41 can be deformed according to the changed slab crown shape. Therefore, a portion of the thin-walled cast 1 in the width direction is not locally pressed strongly, the shape of the thin-walled cast 1 can be kept constant, and meandering control can be stably performed by the pinch roll 41, making it possible to transport the thin-walled cast 1 stably.

[0040] In this embodiment, a temperature measuring means 44 for measuring the temperature of the thin-walled cast 1 clamped between the pinch rolls 41, 41 is provided upstream of the pinch roll 41 in the conveying direction F of the thin-walled cast 1. This makes it possible to measure the temperature of the thin-walled cast 1 clamped between the pinch rolls 41, 41, and adjust the deformation amount and pressing force of the pinch roll 41 taking into account the strength of the thin-walled cast 1, thereby suppressing deformation of the thin-walled cast 1.

[0041] Furthermore, in this embodiment, the pinch roll deformation means 42 is a backup roll arranged on the back side of the pinch roll 41. Therefore, by bending the pinch roll 41 with the backup roll, it is possible to deform the pinch roll 41 into a shape corresponding to the slab crown of the thin slab 1, and it becomes possible to transport the thin slab 1 stably.

[0042] In addition, in this embodiment, a second shape measuring means 46 for measuring the shape of the thin-walled cast 1 clamped between the pinch rolls 41, 41 is arranged downstream of the pinch roll 41 in the conveying direction F of the thin-walled cast 1. Therefore, by adjusting the deformation amount and pressing force of the pinch roll 41 according to the shape of the thin-walled cast 1 measured by the second shape measuring means 46, deformation of the thin-walled cast 1 can be further suppressed.

[0043] In addition, in this embodiment, the shape measuring means 43 arranged upstream of the pinch roll 41 in the transport direction F of the thin-walled cast 1 also has the function of a meandering detection means 45 that detects the amount of meandering of the thin-walled cast 1.Therefore, the meandering amount of the thin-walled cast 1 can be detected by the meandering detection means 45 and meandering control can be performed by the pinch roll 41, making it possible to transport the thin-walled cast 1 even more stably.

[0044] The thin-walled cast slab manufacturing apparatus 10 of this embodiment and the thin-walled cast slab manufacturing method of this embodiment are equipped with a continuous casting machine 20 and the thin-walled cast slab pinch roll unit 40 of this embodiment, and the thin-walled cast slab pinch roll unit 40 is configured to clamp and transport the thin-walled cast slab 1 formed by the continuous casting machine 20 in the thickness direction, thereby suppressing meandering of the thin-walled cast slab 1 and suppressing deformation of the thin-walled cast slab 1, and making it possible to produce high-quality thin-walled cast slabs 1 with stable shapes.

[0045] In this embodiment, the continuous casting machine 20 is a twin-roll continuous casting machine that supplies molten steel 3 to a molten steel pool 26 formed by a pair of rotating cooling rolls 21, 21 and a pair of side weirs 25, and produces a thin-walled cast 1 by forming and growing a solidified shell 5, 5 on the circumferential surface of the cooling rolls 21, 21, making it possible to continuously cast the thin-walled cast 1 in a stable manner.

[0046] The pinch roll unit 40 for thin slabs, the thin slab manufacturing apparatus 10, and the thin slab manufacturing method, which are embodiments of the present invention, have been specifically described above, but the present invention is not limited to this and can be modified as appropriate within the scope of the technical concept of the invention. In this embodiment, the continuous casting machine has been described as being a twin-roll continuous casting machine shown in FIG. 3, but the continuous casting machine is not limited to this and may be any machine that continuously casts thin-walled cast strips.

[0047] In addition, in this embodiment, a backup roll arranged on the back side of the pinch roll has been described as an example of the pinch roll deforming means, but the present invention is not limited thereto. For example, as shown in Fig. 8, the pinch roll deforming means 42 may be an outer diameter adjusting means 50 arranged inside the pinch roll 41. This outer diameter adjusting means 50 includes a guide hole 51 having a tapered surface that gradually slopes radially inward from the width end toward the width center, and cores 52, 52 inserted into this guide hole 51 and moving along the tapered surface. In addition, a central hydraulic chamber 53 is formed in the width center of the guide hole 51 (between the cores 52), and end hydraulic chambers 54, 54 are formed at the width end portions of the guide hole 51. By adjusting the hydraulic pressure in the central hydraulic chamber 53 and the end hydraulic chambers 54, 54, the core 52 is moved in the width direction, thereby making it possible to adjust the outer diameter of the pinch roll 41 at the center of its width. [Example]

[0048] The results of experiments carried out to confirm the effects of the present invention will be described below. Thin cast slabs were manufactured using the thin cast slab manufacturing apparatus shown in Figs.

[0049] The cooling roll was 1000 mm wide, 1200 mm in diameter, and had an internal Cu sleeve and was water-cooled. Four pinch roll units were installed, with work rolls having a diameter of 200 mm (internal water cooling) and backup rolls having a diameter of 400 mm. Both the work rolls and backup rolls had a flat shape. The pinch roll unit closest to the continuous casting machine was the pinch roll unit 40 for thin slabs described in this embodiment.

[0050] The casting conditions were set as follows: Steel type: Low-carbon aluminum-killed steel (0.05% C by mass - 0.03% Al by mass) Casting speed: 50m per minute Casting thickness: 3.5mm Amount of molten steel per cast: 20t Time from start of casting to steady state: 3 minutes Time from start to finish of casting (when casting is complete): 15 minutes Meandering control method: Pinch roll, leveling control.

[0051] In the inventive examples, the shape of the thin-walled cast slab was measured, and the pinch rolls were deformed in accordance with the crown of the thin-walled cast slab. In the comparative examples, the pinch rolls were not deformed. The resulting thin-walled cast slab was fully coiled and then recoiled, and the maximum flatness over the entire length was evaluated using a two-dimensional flatness meter as shown in Figure 9. The evaluation results are shown in Table 1.

[0052] [Table 1]

[0053] In the comparative example, the pinch rolls were not deformed according to the shape of the thin slab, so the meandering of the thin slab could not be adequately controlled. As a result, the meandering amount exceeded 70 mm at the 10 ton casting stage, causing the edge of the thin slab to contact the housing of the in-line rolling mill, and casting was stopped. In addition, the thin slab exhibited central elongation (wavy at the center of its width) and its maximum flatness was 4.8%. In the inventive example, the pinch rolls were deformed according to the shape of the thin slab, so the meandering of the thin slab could be adequately controlled, with the maximum meandering amount being 27 mm. In addition, the thin slab had some lateral elongation (a state in which both ends were wavy), and its maximum flatness was 1.2%.

[0054] From the above experimental results, it has been confirmed that the present invention can provide a pinch roll unit for thin slabs, an apparatus for manufacturing thin slabs, and a method for manufacturing thin slabs, which can maintain the shape of the thin slab constant and stabilize casting while ensuring meandering control by the pinch rolls, even if the slab crown of the thin slab changes during casting. [Explanation of symbols]

[0055] 1 Thin-walled cast billets 3 Molten steel (molten metal) 5 Solidified shell 10. Thin-walled billet manufacturing equipment 20 Continuous casting machine 21 Cooling roll 25 Side Weir 26 Molten steel pool (molten metal pool) 40 Pinch roll unit for thin billet 41 Pinch Roll 42 Pinch roll deformation means 43 Shape measuring means 44 Temperature measurement means 45 Meandering detection means 46 Second shape measuring means

Claims

1. A pinch roll unit for thin-walled cast strips that sandwiches and transports thin-walled cast strips formed by continuous casting in a thickness direction, pinch rolls that sandwich the thin-walled cast strip; a shape measuring means disposed upstream of the pinch rolls in a conveying direction of the thin-walled cast strip, the shape measuring means measuring a shape of the thin-walled cast strip sandwiched between the pinch rolls; and a pinch roll deformation means for deforming the pinch roll, A pinch roll unit for thin-walled cast slabs, characterized in that the pinch rolls are deformed to match the crown shape of the thin-walled cast slab measured by the shape measuring means, and the deformed pinch rolls clamp the thin-walled cast slab while suppressing deformation of the thin-walled cast slab.

2. 2. A pinch roll unit for thin-walled cast slabs according to claim 1, characterized in that it is provided with a temperature measuring means arranged upstream of the pinch rolls in the transport direction of the thin-walled cast slabs, and which measures the temperature of the thin-walled cast slabs clamped between the pinch rolls.

3. 3. The pinch roll unit for thin-walled cast strips according to claim 1, wherein the pinch roll deformation means is a backup roll arranged on the back side of the pinch roll.

4. 3. The pinch roll unit for thin cast strips according to claim 1, wherein the pinch roll deforming means is an outer diameter adjusting means disposed inside the pinch roll.

5. A pinch roll unit for thin-walled cast slabs according to any one of claims 1 to 4, characterized in that a second shape measuring means for measuring the shape of the thin-walled cast slab clamped between the pinch rolls is arranged downstream of the pinch rolls in the transport direction of the thin-walled cast slab.

6. A pinch roll unit for thin-walled cast slabs according to any one of claims 1 to 5, characterized in that a meandering detection means for detecting the amount of meandering of the thin-walled cast slab is arranged upstream of the pinch rolls in the transport direction of the thin-walled cast slab.

7. A continuous casting machine for continuously casting a thin-walled cast strip, and the pinch roll unit for a thin-walled cast strip according to any one of claims 1 to 6, a pinch roll unit for pinching and conveying the thin billet formed by the continuous casting machine in a thickness direction;

8. 8. The apparatus for manufacturing thin slabs according to claim 7, wherein the continuous casting machine is a twin-roll continuous casting machine that supplies molten metal to a molten metal pool formed by a pair of rotating chill rolls and a pair of side weirs, and produces thin slabs by forming and growing a solidified shell on the circumferential surface of the chill rolls.

9. A method for producing a thin cast slab, comprising: pinching and conveying a thin cast slab formed by a continuous casting machine in a thickness direction by the pinch roll unit for thin cast slabs according to any one of claims 1 to 6.

10. 10. The method for producing a thin slab according to claim 9, wherein the continuous casting machine is a twin-roll continuous casting machine that supplies molten metal to a molten metal pool formed by a pair of rotating chill rolls and a pair of side weirs, and produces a thin slab by forming and growing a solidified shell on the circumferential surface of the chill rolls.

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