JP7765701B2 - Pinch roll unit for thin cast slabs, thin cast slab manufacturing device, and thin cast slab manufacturing method - Google Patents

Description

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.

As an apparatus for producing thin metal slabs, for example, as shown in Patent Documents 1 and 2, a twin-roll continuous casting machine is provided that has a pair of chill rolls that have an internal water-cooling structure and rotate in opposite directions. Molten metal is supplied to a molten metal pool formed by the pair of chill rolls and a pair of side weirs, causing solidified shells to form and grow 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 the roll kiss point to produce thin slabs of a predetermined thickness. Such twin-roll continuous casting machines are used for a variety of metals.

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

Patent Document 3 also discloses a method and apparatus for manufacturing thin-walled slabs, which involves placing a magnetic field generator above a tundish, maintaining the molten metal surface flowing toward a pair of chill rolls positioned 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 withdrawing the resulting thin-walled slab upward.

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.

Patent Documents 4 to 6 propose a means for suppressing meandering of thin-walled cast slabs by leveling the thin-walled cast slabs 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 pressure applied by the pinch rolls to the slab, thereby guiding the slab in the opposite direction to the meandering direction and eliminating the meandering.

Japanese Patent Application Publication No. 02-092438 Japanese Patent Application Laid-Open No. 2017-087259 Japanese Unexamined Patent Publication No. 130750/1983 Japanese Patent Application Publication No. 11-156504 Japanese Patent Application Publication No. 08-206790 Special Publication No. 2003-522024 Japanese Patent Application Publication No. 08-215814

The cross-sectional shape of a thin-walled cast slab perpendicular to the casting direction is typically convex, with the thickness at the center of the width becoming thinner toward the width ends. The thickness curve from the width center to the width ends (hereinafter referred to as the cast slab crown) and the thickness difference can take on various values depending on the width and thickness of the thin-walled cast slab, as well as its composition. Therefore, if the shape of the pinch roll barrel is set based on the shape of the cast slab crown in advance, it is possible to precisely control the widthwise distribution of pressure, enabling more stable and reliable control of meandering.

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 (or the chill roll in a twin-roll continuous caster) 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.

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.

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.

The present invention was 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 can maintain a consistent shape of the thin slab and stabilize casting while ensuring meandering control by the pinch rolls, even if the slab crown of the thin slab changes during casting.

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 the thickness direction, and is equipped with pinch rolls that sandwich the thin slab, a shape measuring means that is arranged upstream of the pinch rolls in the transport direction of the thin slab and measures the shape of the thin slab sandwiched between the pinch rolls, and a pinch roll deformation means that deforms the pinch rolls, and is characterized in that the pinch rolls are deformed to match the crown shape of the thin slab measured by the shape measuring means, and the deformed pinch rolls sandwich the thin slab while suppressing deformation of the thin slab.

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 thin-walled cast piece in the width direction 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.

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.

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.

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.

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 the 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.

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.

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.

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 circumferential surface of the chill rolls to produce thin-walled cast slabs.
In this case, it becomes possible to stably continuously cast thin-walled cast pieces.

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.

In the method for producing a thin-walled 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 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.

As described above, the present invention makes it possible to provide a pinch roll unit for thin slabs, a thin slab manufacturing apparatus, and a thin slab manufacturing method that can maintain a consistent shape of the thin slab and stabilize casting while ensuring meandering control by the pinch rolls, even if the slab crown of the thin slab changes during casting.

1 is a schematic explanatory diagram of a thin-walled cast slab manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view of the thin-walled cast slab manufacturing apparatus shown in FIG. 1 . 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. 1 . 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. FIG. 1 is an explanatory diagram of a pinch roll unit for a thin cast strip according to an embodiment of the present invention. 6 is an explanatory diagram of a pinch roll deformation means provided in the pinch roll unit for thin-walled cast strips shown in FIG. 5 (Nippon Steel Corporation, "Understanding Iron and Steel," November 10, 2004, Nippon Jitsugyo Publishing, p. 96). FIG. 4 is an explanatory diagram of the amount of bending of a pinch roll. 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. FIG. 10 is an explanatory diagram of flatness in an example.

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.

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 transport section 30 includes a pinch roll unit 40 for thin-walled cast slabs that clamps and transports the thin-walled cast slabs 1 in the thickness direction, an in-line rolling mill 31, a looper 32, a coiler 33, and a plurality of guide rolls 34.

As shown in Figure 3, the continuous casting machine 20 is a twin-roll continuous casting machine equipped with a pair of chill rolls 21, 21, side weirs 25 arranged at the widthwise ends of the pair of chill rolls 21, 21, a tundish 28 that holds molten steel 3 to be supplied to a molten steel pool 26 defined by the pair of chill 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 26.

In this continuous casting machine 20, the molten steel 3 comes into contact with the chill 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 chill rolls 21, 21, and the solidified shells 5, 5 formed on the pair of chill rolls 21, 21 are pressed together at the roll kiss points, thereby casting a thin-walled cast 1 of a predetermined thickness.
In the transport section 30, the formed thin billet 1 is transported 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.

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

As shown in Figures 2 and 5, the pinch roll unit 40 for thin billet in this embodiment, which is arranged in the transport section 30, is equipped with pinch rolls 41, 41 that clamp the thin billet 1, a shape measuring means 43 that is arranged upstream of the pinch rolls 41, 41 in the transport direction F of the thin billet 1 and measures the shape of the thin billet 1, and pinch roll deformation means 42, 42 that deform the pinch rolls 41, 41.The pinch rolls 41, 41 are deformed according to the shape (bill crown) of the thin billet 1 measured by the shape measuring means 43, and the deformed pinch rolls 41, 41 clamp the thin billet 1 in the thickness direction.

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 disposed upstream of the pinch rolls 41, 41 in the transport direction F of the thin-walled cast 1.
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 1 is disposed upstream of the pinch rolls 41, 41 in the transport direction F of the thin cast 1.
Furthermore, in this embodiment, as shown in FIG. 5, a second shape measuring means 46 for measuring the shape of the thin-walled cast 1 sandwiched between the pinch rolls 41, 41 is disposed downstream of the pinch rolls 41, 41 in the transport direction F of the thin-walled cast 1.

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 cast 1 in the width direction, it is possible to measure the cross-sectional shape (cast crown) of the thin cast 1. Furthermore, by extending the X-ray transmission type thickness gauge to the outside of the width direction end of the thin cast 1, it is possible to detect meandering of the thin cast 1. That is, in this embodiment, the shape measuring means 43 also functions as the meandering detection means 45.

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, which are the pinch roll deformation means 42, in accordance with the shape (cast piece crown) of the thin cast piece 1.
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.

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 1 .
Here, the bending amount of the pinch roll 41 is preferably set to a range of 10 μm to 150 μm when the width of the thin-walled 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.

In addition, in this embodiment, as shown in Figures 2 and 5, a temperature measuring means 44 for measuring the temperature of the thin 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 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 cast 1 held between the pinch rolls 41, 41.

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 1 is arranged upstream of the pinch rolls 41, 41 in the transport direction F of the thin cast 1, and the meandering of the thin cast 1 is controlled by controlling the operation of the pinch rolls 41, 41 in accordance with the amount of meandering of the thin cast 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.

Furthermore, in this embodiment, as shown in FIG. 5, a second shape measuring means 46 for measuring the shape of the thin cast slab 1 held between the pinch rolls 41, 41 is disposed downstream of the pinch rolls 41, 41 in the conveying direction F of the thin cast slab 1. This second shape measuring means 46 measures the shape of the thin cast slab 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.

In the pinch roll unit 40 for thin slabs of this embodiment configured as described above, the shape (slab crown) of the thin slab 1 clamped between the pinch rolls 41 is measured by a shape measuring means 43 arranged upstream of the pinch rolls 41 in the transport direction F of the thin slab 1, and the pinch roll deformation means 42 deforms the pinch rolls 41 in accordance with 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 in accordance with the changed slab crown shape.
Therefore, a portion of the width direction of the thin-walled cast 1 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.

In this embodiment, a temperature measuring means 44 for measuring the temperature of the thin-walled cast 1 held between the pinch rolls 41, 41 is provided upstream of the pinch roll 41 in the transport direction F of the thin-walled cast 1. This makes it possible to measure the temperature of the thin-walled cast 1 held 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.

In addition, in this embodiment, the pinch roll deformation means 42 is a backup roll arranged on the back side of the pinch roll 41. By bending the pinch roll 41 using the backup roll, the pinch roll 41 can be deformed into a shape that corresponds to the cast crown of the thin cast slab 1, making it possible to transport the thin cast slab 1 stably.

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 disposed downstream of the pinch roll 41 in the transport 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.

In addition, in this embodiment, the shape measuring means 43, which is arranged upstream of the pinch rolls 41 in the transport direction F of the thin cast slab 1, also functions as a meandering detection means 45 that detects the amount of meandering of the thin cast slab 1. Therefore, the meandering amount of the thin cast slab 1 can be detected by the meandering detection means 45, and meandering control can be performed by the pinch rolls 41, making it possible to transport the thin cast slab 1 more stably.

The thin slab manufacturing apparatus 10 and the thin slab manufacturing method of this embodiment are equipped with a continuous casting machine 20 and the thin slab pinch roll unit 40 of this embodiment. The thin slab pinch roll unit 40 is configured to clamp and transport the thin slab 1 formed by the continuous casting machine 20 in the thickness direction, thereby suppressing meandering and deformation of the thin slab 1, and enabling the production of high-quality thin slabs 1 with a stable shape.

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 chill 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 chill rolls 21, 21, thereby enabling stable continuous casting of the thin-walled cast 1.

The pinch roll unit 40 for thin cast slabs, the thin cast slab manufacturing apparatus 10, and the thin cast slab manufacturing method, which are embodiments of the present invention, have been specifically described above. However, 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 twin-roll continuous casting machine shown in FIG. 3 has been used as an example of the continuous casting machine, but the present invention is not limited to this and any machine that can continuously cast thin-walled cast strips may be used.

In addition, in this embodiment, a backup roll disposed on the back surface of the pinch roll has been described as an example of the pinch roll deformation means, but the present invention is not limited thereto. For example, as shown in Fig. 8, the pinch roll deformation means 42 may be an outer diameter adjustment means 50 disposed inside the pinch roll 41. This outer diameter adjustment 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 the guide hole 51 and moving along the tapered surface. Furthermore, 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.

The following describes the results of experiments conducted to confirm the effects of the present invention. Thin cast slabs were manufactured using the thin cast slab manufacturing apparatus shown in Figures 1 to 7.

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

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

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 strip 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.

In the comparative example, the pinch rolls were not deformed according to the shape of the thin-walled cast strip, so the meandering of the thin-walled cast strip could not be adequately controlled. As a result, the amount of meandering exceeded 70 mm at the time of 10 ton casting, causing the edge of the thin-walled cast strip to contact the housing of the in-line rolling mill, and casting was stopped. In addition, the thin-walled cast strip 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-walled slab, so that the meandering of the thin-walled slab could be adequately controlled, with the maximum meandering amount being 27 mm. In addition, the thin-walled slab had slight lateral elongation (a state in which both ends were wavy), and its maximum flatness was 1.2%.

These experimental results confirm that the present invention can provide a pinch roll unit for thin slabs, a thin slab manufacturing device, and a thin slab manufacturing method that can maintain a consistent shape of the thin slab and stabilize casting while ensuring meandering control by the pinch rolls, even if the slab crown of the thin slab changes during casting.

1 Thin-walled cast slab 3 Molten steel (molten metal)
5 Solidified shell 10 Thin-walled cast slab manufacturing device 20 Continuous casting machine 21 Cooling roll 25 Side weir 26 Molten steel pool portion (molten metal pool portion)
40 Thin-walled cast pinch roll unit 41 Pinch roll 42 Pinch roll deformation means 43 Shape measurement means 44 Temperature measurement means 45 Meandering detection means 46 Second shape measurement means

Claims (10)

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 the conveying direction of the thin-walled cast strip, the shape measuring means measuring the 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. The pinch roll unit for thin slabs described in claim 1 is characterized in that it is equipped with a temperature measuring means that is positioned upstream of the pinch rolls in the direction of transport of the thin slabs and measures the temperature of the thin slabs held between the pinch rolls. A pinch roll unit for thin-walled cast strips as described in claim 1 or claim 2, characterized in that the pinch roll deformation means is a backup roll arranged on the back side of the pinch roll. A pinch roll unit for thin-walled cast strips as described in claim 1 or claim 2, characterized in that the pinch roll deformation means is an outer diameter adjustment means arranged inside the pinch roll. A pinch roll unit for thin 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 slab clamped between the pinch rolls is disposed downstream of the pinch rolls in the transport direction of the thin slab. A pinch roll unit for thin 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 slab is disposed upstream of the pinch rolls in the transport direction of the thin slab. 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; The thin-walled cast slab manufacturing apparatus described in claim 7, characterized in that 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-walled cast slabs by forming and growing a solidified shell on the circumferential surface of the chill rolls. A method for producing thin slabs, characterized in that the thin slabs formed by a continuous casting machine are clamped in the thickness direction and transported by the pinch roll unit for thin slabs described in any one of claims 1 to 6. The method for producing thin slabs described in claim 9, characterized in that 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.