JP2018058106A - Continuous casting equipment and plate crown control method - Google Patents

Abstract

[PROBLEMS] To produce a product with stable sheet rolling and high sheet thickness accuracy in the sheet width direction by controlling the sheet crown of the cast strip using a straightening device during continuous casting of a twin drum type thin cast slab. To do. A twin-drum continuous casting apparatus that forms a molten metal reservoir by a pair of cooling drums and side weirs and casts the molten metal stored in the molten metal reservoir while rotating the pair of cooling drums; It is arranged downstream of the twin-drum type continuous casting machine in the casting direction, and is arranged between the rolling machine for rolling the cast slab and between the twin-drum type continuous casting machine and the rolling machine, and has at least a convex roll profile. A continuous casting facility comprising: an indenting roll having an elevating mechanism for raising and lowering the indenting roll with respect to a slab in tension in a casting direction, and a correction device for correcting the shape of the slab Is done. [Selection] Figure 3

Description

  The present invention relates to a continuous casting facility including a twin-drum type continuous casting apparatus, and a plate crown control method in the facility.

  In the twin-drum type continuous casting apparatus, a metal melt reservoir is formed by a pair of continuous casting cooling drums (hereinafter also referred to as “cooling drums”) and side weirs arranged opposite to each other in the horizontal direction. A pair of cooling drums is rotated with the stored molten metal to cast a thin cast piece (hereinafter referred to as “casting strip”) (for example, Patent Document 1). When the molten metal is stored in the molten metal reservoir, the cooling drums are rotated downward from above, respectively, and the molten metal is sent down as a cast strip while solidifying and growing on the peripheral surface of the cooling drum. The cast strip fed from the cooling drum is fed horizontally by a pinch roll and adjusted to a desired plate thickness by a downstream in-line mill. The cast strip whose thickness is adjusted by the in-line mill is wound into a coil by a winding device installed downstream of the in-line mill.

  In such a twin-drum type continuous casting apparatus, the cooling drum is generally at a low temperature before the start of casting, and when the casting is started, the temperature is raised by contact with the molten metal. Further, the cooling drum is cooled from the inner surface by a cooling medium (for example, cooling water) so as not to exceed a predetermined temperature. Hereinafter, the period when the temperature of the cooling drum reaches a predetermined temperature and becomes constant is the steady casting period, the arbitrary point in the steady casting period is the steady casting, and the temperature of the cooling drum in the steady casting period is the steady temperature . The state during the steady casting period is referred to as a steady state.

  The profile of the cooling drum changes over time from the start of casting until it reaches a steady state. For this reason, the profile of the cooling drum is set so that the plate profile (plate crown) of the cast strip at the time of steady casting becomes a desired plate profile.

  Here, FIG. 13 shows changes in the profiles of the cooling drums 10a and 10b and the plate profile of the casting strip S with the elapsed time from the start of casting when the casting strip S is manufactured by the conventional twin drum type continuous casting apparatus. Show. In addition, the plate profile of the casting strip S shows a state in which the cooling drums 10a and 10b are cast without shifting, and before the reduction in the in-line mill is performed.

  The cooling drums 10a and 10b at the start of casting are set to have a concave profile in which the center in the axial direction is recessed as shown in a state A in FIG. The cast strip S rolled by the cooling drums 10a and 10b having such a profile has a plate profile whose center in the plate width direction (that is, the axial direction) is convex.

  Next, when a certain time has elapsed from the start of casting, the cooling drums 10a and 10b expand (expand) in the center in the axial direction due to heat input from the molten metal, and casting starts as shown in state B in FIG. It changes to a concave profile smaller than the time (state A). For this reason, the plate profile of the casting strip S has a convex shape with a smaller crown amount than the casting strip S at the start of casting (state A).

  Thereafter, after a further time has elapsed from the start of casting and reached a steady state, the cooling drums 10a and 10b are further expanded (expanded) by heat input from the molten metal, and are shown in a state C in FIG. Thus, the hollow at the center in the axial direction changes to a slightly concave profile. Therefore, the plate profile of the cast strip S has a convex shape with a smaller crown amount than in the state B.

  The time required to reach state C from state A in FIG. 13 varies depending on the steel type (melting temperature) of the molten metal, the thickness of the casting strip, the rotational speed of the cooling drum and the cooling efficiency, but is approximately about from the start of casting. About 30 seconds.

  Here, when the cast strip cast by the twin-drum type continuous casting apparatus is rolled by an in-line mill as in Patent Document 1, the temperature of the cast strip on the in-line mill entry side is about 1000 ° C. It is possible to adjust the slight plate crown by creating a flow (widening). However, the in-line mill did not have a crown control capability sufficient to cope with the cast strip of the plate profile as shown in the state A and the state B in FIG. In an in-line mill, when a plate profile cast strip as shown in state A in FIG. 13 is rolled with such a large force that the crown amount is adjusted, the middle elongation at the center of the plate becomes extremely large. As a result, meandering and squeezing occur, and the cast strip is easily broken.

  Increasing the tension of the in-line mill is effective for plate breakage due to drawing due to the middle elongation of the plate shape in the in-line mill. However, in order to increase the tension of the inline mill, it is necessary to increase the pressing force of the pinch roll. If the pressing force of the pinch roll is increased, the cast strip may be rolled with the pinch roll. When the cast strip is rolled by the pinch roll, the plate breaks due to the meandering by the pinch roll or the severe shape defect causes the plate breakage due to the drawing by the in-line mill. When the plate breakage occurs, the molten metal remaining in the molten metal reservoir is immediately discarded, resulting in a significant yield reduction. Even when a cast strip is wound up by a twin-drum type continuous casting apparatus without causing plate breakage, the following problems occur in rolling in a subsequent process.

  For example, in order not to change the plate shape in the subsequent cold rolling or warm rolling, it is necessary to perform rolling so that the crown ratio of the cast strip does not change. For this purpose, it is necessary to use a rolling mill excellent in shape control (for example, a CRS rolling mill, a multi-stage cluster rolling mill, etc.), and equipment costs for newly installing these rolling mills are generated.

  Depending on the type of steel and the customer, it is manufactured with a twin-drum continuous casting device when the specifications required for the product crown are strict or when the product is used after being processed and laminated. Of the cast strip, the large part of the plate crown is mismatched on the product and cut. Since the cut portion is small in weight and difficult to be diverted, it is scrapped.

  As described above, in the conventional twin-drum type continuous casting apparatus, the profile change due to the thermal expansion change of the cooling drum from the start of casting affects the subsequent process, and the equipment cost for producing the desired casting strip is generated. The yield was reduced.

  As a method for solving such a problem, for example, Patent Document 2 discloses a method for increasing the cooling efficiency of the central portion of the cooling drum in order to suppress the change of the profile due to thermal expansion. Patent Document 3 discloses a method of adjusting a hydraulic pressure of oil filled in a hollow chamber chamber provided in a cooling drum in order to cancel a profile change due to thermal expansion.

JP 2000-343103 A JP-A-6-328205 Japanese Patent Laid-Open No. 1-133642 JP-A-57-103706

  However, the method for increasing the cooling efficiency of the central portion of the cooling drum disclosed in Patent Document 2 is to reduce the amount of thermal expansion of the cooling drum until the steady state, and is shown in state A or state B in FIG. Such unsteady parts cannot be handled. Although the method of adjusting the oil pressure of the oil filled in the hollow chamber of the cooling drum disclosed in Patent Document 3 is effective, the profile change of the cooling drum due to the thermal expansion of the cooling drum, and the chamber This does not necessarily match the profile change of the cooling drum by adjusting the oil pressure of the filled oil. For this reason, the influence of heat on the cooling drum cannot be canceled out, and the plate shape that has changed from middle elongation to end elongation at the time of rolling may newly induce quarter elongation.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a cooling drum from a casting start to a steady state for a casting strip manufactured by a twin drum type continuous casting facility. It is an object of the present invention to provide a new and improved continuous casting equipment and a plate crown control method capable of reducing crown change due to thermal expansion and improving the plate thickness accuracy in the plate width direction.

  In order to solve the above-described problem, according to an aspect of the present invention, a molten metal storage section is formed by a pair of cooling drums and side weirs, and the molten metal storage section is stored while rotating the pair of cooling drums. A twin-drum continuous casting device for casting a molten metal, a rolling device for rolling a cast slab disposed downstream of the twin-drum continuous casting device in the casting direction, a twin-drum continuous casting device, and a rolling device; And has a push roll having at least a convex roll profile and a lifting mechanism for raising and lowering the push roll with respect to the slab in tension in the casting direction to correct the shape of the slab There is provided a continuous casting facility comprising a straightening device.

  The roll profile of the push roll may be configured to be changeable.

  For example, the push roll may be a roll profile variable roll whose roll profile can be controlled by supplying and discharging a pressure medium to and from a pressurizing chamber disposed therein.

  The roll profile of the pushing roll may be changed based on the relationship between the casting start time calculated in advance and the size of the plate crown of the slab.

  The pushing amount of the pushing roll by the lifting mechanism may be set based on the relationship between the casting start time calculated in advance and the size of the plate crown of the slab.

  The continuous casting facility may include a plate thickness measuring device that measures the plate thickness of the slab on at least one of the upstream side and the downstream side in the casting direction with respect to the straightening device. The plate thickness measuring device measures the plate thickness at two locations including at least the plate width center in the plate width direction of the slab. The plate crown of the slab is calculated based on the measured plate thickness and measurement position.

  At least one of the pushing amount of the pushing roll and the roll profile by the lifting mechanism may be set based on the calculated plate crown of the slab.

  The continuous casting facility may further include a temperature distribution measuring device that measures the temperature in the plate width direction of the slab on at least one of the upstream side and the downstream side in the casting direction with respect to the straightening device.

  The temperature distribution measuring device includes at least three plate thermometers arranged in the plate width direction of the cast slab, and the plate thermometers may be arranged at least in the center of the plate width of the slab and in the vicinity of both ends of the plate width.

  Or you may comprise a temperature distribution measuring apparatus from the plate thermometer which can move to the plate width direction of a slab.

  Moreover, in order to solve the said subject, according to another viewpoint of this invention, a metal melt storage part is formed with a pair of cooling drum and a side dam, and it turns into a metal melt storage part, rotating a pair of cooling drum. In a continuous casting facility comprising a twin-drum type continuous casting apparatus that casts a stored molten metal, and a rolling device that is arranged on the downstream side in the casting direction of the twin-drum type continuous casting apparatus and that rolls the cast slab, A method for controlling a crown of a slab cast by a twin drum continuous casting apparatus, wherein the continuous casting equipment is disposed between the twin drum continuous casting apparatus and the rolling apparatus and has at least a convex roll profile. It has an intrusion roll and an elevating mechanism that raises and lowers the intrusion roll with respect to the slab in tension in the casting direction, and is equipped with a correction device that corrects the shape of the slab and is calculated in advance. Based on the relationship between the casting start time and the size of the plate crown of the slab, the lifting mechanism is controlled according to the plate crown of the slab that changes in time with the passage of time from the casting start time. A plate crown control method for changing the push-in amount is provided.

  Here, the pushing amount of the pushing roll is set to the first pushing amount with the plate crown of the slab as a target value at the start of casting, and is acquired in advance after the slab is bitten in the rolling device. Based on the relationship between the pressing amount of the pressing roll and the plate crown, the width may be changed according to the plate crown of the slab passing through the correction device.

  Alternatively, the pushing amount of the pushing roll is set to the first pushing amount with the plate crown of the slab as a target value at the start of casting, and after the slab is bitten in the rolling device, the indenting acquired in advance Based on the relationship between the roll profile of the roll and the plate crown, it may be changed according to the plate crown of the slab passing through the straightening device.

  The continuous casting equipment further includes a temperature distribution measuring device for measuring the temperature in the plate width direction of the slab on at least one of the upstream side and the downstream side in the casting direction with respect to the straightening device. Based on the measured temperature distribution in the plate width direction of the slab, a parameter representing the temperature asymmetry in the plate width direction of the slab is calculated, and the relationship between the pre-calculated parameter of the slab and the size of the plate crown is calculated. Based on this, the roll profile at the time of contact when the push roll is in contact with the slab may be determined.

  As a parameter representing the temperature asymmetry in the plate width direction of the slab, for example, a temperature asymmetry parameter which is a coefficient representing an asymmetric component of the temperature distribution in the quadratic expression representing the temperature distribution in the plate width direction of the slab, An integral temperature asymmetric parameter that is an area ratio of two areas obtained by dividing an area representing the temperature distribution in the sheet width direction into two at the sheet width center, or two positions that are symmetrical with respect to the sheet width center of the slab and the position Any one of the temperature moments represented on the basis of the temperature of the slab may be used.

  The roll profile at the time of contact of the pressing roll may be changed by changing the roll profile in the axial direction of the pressing roll, or by adjusting the pressing amount of the pressing roll to the slab at a plurality of axial pressing positions.

  Further, when the plate crown of the slab is in a steady state, the push roll may be moved so as not to press the slab by the lifting mechanism.

  As described above, according to the present invention, for a cast strip manufactured by a twin-drum type continuous casting facility, the crown change due to the thermal expansion of the cooling drum from the start of casting to the steady state is reduced, and the plate in the plate width direction is reduced. Thickness accuracy can be improved.

It is explanatory drawing which shows schematic structure of the manufacturing process of the casting strip which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the connection part of the front-end | tip of a casting strip at the time of the rolling start which concerns on the same embodiment, and a dummy sheet | seat. It is explanatory drawing which shows the structure of the correction apparatus which concerns on the same embodiment. It is a graph which shows an example of the indentation amount of an indentation roll, the board crown of a casting strip, and elongation rate. It is a graph which shows an example of the relationship between the pushing amount of a pushing roll, and the board crown variation | change_quantity when changing the roll crown of a pushing roll. It is explanatory drawing for demonstrating the outline | summary of the plate crown control of the casting strip which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows the installation position of the temperature distribution measuring apparatus with respect to the correction apparatus which concerns on the same embodiment. It is explanatory drawing explaining the temperature distribution measuring method of the board width direction by a temperature distribution measuring apparatus. It is a graph which shows the example of 1 relationship between a temperature asymmetric parameter and a plate crown difference. It is explanatory drawing explaining correction of the pushing amount of the pushing roll in the board width direction both ends based on the temperature distribution of a casting strip. It is explanatory drawing which shows the example of 1 structure which changes the roll profile at the time of casting of an indentation roll. It is explanatory drawing explaining the case where the temperature distribution of the plate width direction of a casting strip is represented by an area as a temperature asymmetric parameter. It is a conceptual diagram which shows the change of the profile of a cooling drum and the plate profile of a casting strip with the elapsed time from the casting start at the time of manufacturing a casting strip with the conventional twin drum type continuous casting apparatus.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. First Embodiment>
(1-1. Casting strip manufacturing process)
First, with reference to FIGS. 1-3, the outline | summary of the manufacturing process which manufactures the casting strip which concerns on the 1st Embodiment of this invention is demonstrated. FIG. 1 is an explanatory view showing a schematic configuration of a manufacturing process of a casting strip (thin cast piece) according to the present embodiment. FIG. 2 is an explanatory view showing a connection portion between the tip of the casting strip S and the dummy sheet 11 at the start of rolling. FIG. 3 is an explanatory diagram showing the configuration of the correction device 80 according to the present embodiment.

  As shown in FIG. 1, the cast strip manufacturing process 1 according to the present embodiment includes, for example, a tundish (storage device) T, a twin drum continuous casting facility 10, an antioxidant device 20, a cooling device 30, A first pinch roll device 40, an inline mill 50, a second pinch roll device 60, a winding device 70, and a correction device 80 are provided.

(Double drum type continuous casting machine)
As shown in FIG. 1, the twin-drum continuous casting apparatus 10 includes, for example, a pair of cooling drums 10a and 10b and side weirs (not shown) arranged on both sides in the axial direction of the pair of cooling drums 10a and 10b. With. The pair of cooling drums 10 a and 10 b and the side dam constitute a molten metal storage unit 15 that stores the molten metal supplied from the tundish T.

  The pair of cooling drums 10a and 10b includes a first cooling drum 10a and a second cooling drum 10b. The first cooling drum 10a and the second cooling drum 10b have a concave profile in which the center in the axial direction is slightly depressed. Moreover, the 1st cooling drum 10a and the 2nd cooling drum 10b are comprised so that adjustment of the space | interval of cooling drum 10a, 10b is possible according to the plate | board thickness (internal quality) of the casting strip S to manufacture. The 1st cooling drum 10a and the 2nd cooling drum 10b are comprised so that a cooling medium (for example, cooling water) can distribute | circulate inside. The cooling drums 10a and 10b can be cooled by circulating the cooling medium inside the cooling drums 10a and 10b.

  In the present embodiment, the first cooling drum 10a and the second cooling drum 10b are set such that, for example, the outer diameter is 800 mm, the drum body length (width) is 1500 mm, and the plate crown of the casting strip S in a steady state is 30 μm (initial Processed). Needless to say, the outer diameter and drum length (width) of the pair of cooling drums 10a and 10b are not limited thereto.

  In the twin drum type continuous casting apparatus 10, as shown in FIG. 2, the dummy sheet 11 is connected to the tip of the casting strip S, and casting is started. A dummy bar 13 having a thickness larger than that of the cast strip S is provided at the tip of the dummy sheet 11, and the dummy sheet 11 is guided by the dummy bar 13. In addition, a protrusion 12 that is thicker than the thickness of the casting strip S is formed at the connection between the tip of the casting strip S and the dummy sheet 11. Rolling (flying touch) in the in-line mill 50 is started after the protrusion 12 has passed through the in-line mill 50.

(Antioxidation equipment)
The antioxidant 20 is a device for performing a process for preventing the surface of the casting strip S immediately after casting from oxidizing and generating scale. In the antioxidant device 20, for example, the amount of oxygen can be adjusted by nitrogen gas. It is preferable to apply the antioxidant 20 as necessary in consideration of the steel type of the cast strip S to be cast.

(Cooling system)
The cooling device 30 is a device that cools the cast strip S whose surface has been subjected to an antioxidant treatment by the antioxidant device 20. The cooling device 30 includes, for example, a plurality of spray nozzles (not shown), and ejects cooling water from the spray nozzles to the surface (upper surface and lower surface) of the casting strip S according to the steel type. Cooling. As an example, the temperature control of the cast strip in the cooling device 30 may use preset control for setting cooling conditions before casting. In that case, by adjusting at least one of the position of the plurality of nozzles arranged in the sheet width direction and the rolling direction and the amount of cooling water supplied from the nozzles, the temperature distribution in the sheet width direction becomes constant. You may control. Further, as another example of the temperature control of the casting strip in the cooling device 30, dynamic control for adjusting the cooling condition during casting may be used. In that case, for example, the position of the nozzle and the amount of cooling water so that the temperature distribution in the plate width direction becomes constant by a temperature distribution measuring device (for example, at least one of the temperature distribution measuring devices 95 and 97 in FIG. 7) during casting. And / or may be controlled.

  A pair of feed rolls 87 may be disposed between the antioxidant device 20 and the cooling device 30. The pair of feed rolls 87 sandwich the cast strip S by a reduction device (not shown), and measure the loop length of the cast strip S between the pair of cooling drums 10a and 10b and the feed roll 87, while A horizontal conveying force is applied to the casting strip S so that the loop length is constant. The feed roll 87 is constituted by a pair of rolls having a roll diameter of 200 mm and a roll body length (width) of 2000 mm, for example.

(First pinch roll device)
The first pinch roll device 40 is a pinch roll device arranged on the entry side of the inline mill 50. Note that a correction device 80 described later is disposed between the first pinch roll device 40 and the inline mill 50. The first pinch roll device 40 includes an upper pinch roll 40a and a lower pinch roll 40b, a housing, a roll chock, a rolling load detection device, and a reduction device (not shown). Each of the upper pinch roll 40a and the lower pinch roll 40b has a hollow channel formed therein, and is configured to allow a cooling medium (for example, cooling water) to flow therethrough. The pinch roll can be cooled by circulating the cooling medium.

  The upper pinch roll 40a and the lower pinch roll 40b may have, for example, a roll diameter of 400 mm and a roll trunk length (width) of 2000 mm. The upper pinch roll 40a and the lower pinch roll 40b are disposed via a roll chock in the housing, and are rotationally driven by a motor (not shown). The upper pinch roll 40a is connected to a pass line adjusting device (not shown) via an upper rolling load detection device (not shown), and the lower pinch roll 40b is a reduction device (not shown). .).

  In the first pinch roll device 40 having such a configuration, when the lower pinch roll 40b is pushed up to the upper pinch roll 40a side by the reduction device, a reduction load applied to the upper pinch roll 40a and the lower pinch roll 40b is detected. A tension is generated in the cast strip S between the first pinch roll device 40 and the straightening device 80. Further, the casting strip S in the pair of pinch rolls 40a and 40b and the inline mill 50 is set so that the tension generated in the casting strip S between the first pinch roll device 40 and the inline mill 50 becomes a preset tension. The moving speed is controlled. Further, on the upstream side and the downstream side of the first pinch roll, position detection devices 41 and 43 for detecting the position of the cast strip may be provided.

(Correcting device)
The straightening device 80 is a device that straightens the shape of the casting strip S that passes therethrough. In the present embodiment, the shape of the cast strip S refers to the cross-sectional shape of the cast strip, that is, the plate crown shape. The straightening device 80 has three rolls 81A, 81B, and 81C arranged along the conveying direction of the casting strip S. As shown in FIG. 3, the rolls 81A, 81B, and 81C are supported by roll chocks 83A, 83B, and 83C, respectively, and the roll chocks 83A, 83B, and 83C are installed in the housings 85A, 85B, and 85C, respectively. Each roll 81A, 81B, 81C may use the same size roll. For example, rolls 81A, 81B, and 81C having a roll diameter of 150 mm and a trunk length of 2000 mm may be used. Each roll 81A, 81B, 81C is a non-driving roll and rotates following the movement of the casting strip S. Further, the correction device 80 is provided with a cooling facility (not shown) for cooling the rolls 81A, 81B, 81C.

  In the correction device 80 according to the present embodiment, as shown in FIG. 3, the rolls 81 </ b> A and 81 </ b> C are installed so that the height positions of the roll shafts are the same. On the other hand, the roll 81B disposed between the roll 81A and the roll 81C functions as a push roll for pushing the casting strip S moving on the line, and is installed so as to be movable up and down by the lifting mechanism 86. The roll 81B is pulled up by a balancer (not shown) provided in the roll chock 83B so as not to fall. Moreover, although not shown in figure, the vertical movement apparatus which moves the raising / lowering mechanism 86 up and down independently may be provided in the both sides (namely, axial direction both ends side of the roll 81B) of the raising / lowering mechanism 86. FIG. Thereby, the position of the raising / lowering mechanism 86 in the axial direction both ends of the roll 81B can be controlled independently.

  Further, the roll 81B according to the present embodiment includes a plurality of hydraulic chambers (not shown). By changing the oil pressure in the hydraulic chamber, the roll profile is changed from a flat state to a convex having a large central diameter. It is possible to change to a mold state. Further, the roll profile can be changed asymmetrically by adjusting the hydraulic pressures of the plurality of hydraulic chambers asymmetrically. On the other hand, the roll 81A and the roll 81C are provided with a speed detector (PLG) that detects the rotation speed of the roll. Based on the rotational speed detected by the speed detector, the sheet passing speed of the cast strip S at each roll position is calculated, and the elongation rate of the cast strip S by the straightening device 80 can be measured.

  The tension applied to the correction device 80 can be generated by giving a speed difference to the rolls of the first pinch roll device 40 and the inline mill 50. The greater the generated tension, the easier the plastic deformation of the cast strip S at the bending portion defined by the rolls 81A, 81B, 81C, even with a small indentation amount and a large roll diameter. The tension applied to the straightening device 80 is not shown, but is measured by a tension roll (not shown) provided between the first pinch roll device 40 and the inline mill 50 and set in advance. The speed of the in-line mill 50 is controlled so as to be a predetermined value.

  Further, plate profile meters 91 and 93 for measuring the plate thickness of the casting strip S are provided on the entry side and the exit side of the correction device 80 as shown in FIGS. By measuring the plate thickness in the plate width direction of the cast strip S with these plate profile meters 91 and 93, the plate crown of the cast strip S can be calculated based on the result. The plate crown amount of the cast strip S is a quadratic approximation of the plate thickness distribution of the cast strip S in the plate width direction, and the plate thickness at the inner side by a predetermined distance from the plate thickness at the center of the plate and the plate definition point. It is calculated by calculating the difference between. The calculation of the plate crown of the casting strip S may be performed by, for example, a control device (not shown) that controls the correction device 80. The control device controls at least one of the roll position and roll profile of the roll 81B based on the calculated plate crown amount. Detailed description of the operation and control by the correction device 80 according to the present embodiment will be described later.

(Inline mill)
The in-line mill 50 is a rolling device that rolls the cast strip S so that the cast strip S has a desired thickness. In the present embodiment, the in-line mill 50 is configured as a six-high rolling mill. That is, the in-line mill 50 includes a pair of work rolls 51a and 51b, intermediate rolls 52a and 52b arranged above and below the work rolls 51a and 51b, and backup rolls 53a and 53b arranged above and below the intermediate rolls 52a and 52b. With. In the present embodiment, for example, work rolls 51a and 51b having a roll diameter of 400 mm, intermediate rolls 52a and 52b having a roll diameter of 450 mm, and backup rolls 53a and 53b having a roll diameter of 1200 mm may be used. The length of each roll may be the same, for example, 2000 mm.

  Further, the inline mill 50 includes an inline mill control device that controls the inline mill, a thickness gauge (none of which is shown), and the like. The work rolls 51a and 51b are rotationally driven by a motor (not shown) and are cooled by cooling water from the entry side and the exit side. Further, a hydraulic cylinder (not shown) is provided above the backup roll 53a to press the backup roll 53a downward.

  The in-line mill 50 starts rolling by tightening the roll gap while rotating the work rolls 51a and 51b of the in-line mill 50 after the tip of the casting strip S cast during the steady casting passes through the in-line mill 50. It has become. Such a rolling method is called a flying touch.

  The inline mill 50 is controlled by an inline mill control device (not shown). The inline mill control device includes, for example, a mill control unit that controls the inline mill 50 in an integrated manner, a hydraulic cylinder control unit that controls a hydraulic cylinder, an intermediate roll shift control unit, a roll rotation control unit, a roll bending force setting unit, and the like. .

  The hydraulic cylinder controller controls the reduction of the hydraulic cylinder connected to the backup roll 53a. The hydraulic cylinder control unit adjusts the roll gap between the work rolls 51a and 51b by controlling the hydraulic cylinder based on an instruction from a mill control unit that controls the inline mill 50 in an integrated manner. At this time, the mill control unit is a plate on which the casting strip S is preset based on the thickness of the casting strip S measured by a thickness gauge (not shown) installed on the exit side of the in-line mill 50. The roll gap is adjusted so as to be formed thick. For example, an X-ray thickness gauge may be used as the thickness gauge. The intermediate roll shift control unit moves the intermediate rolls 52a and 52b in the roll axis direction based on instructions from the mill control unit. The roll rotation control unit controls the rotation speed of the work rolls 51a and 51b based on an instruction from the mill control unit. The roll bending setting unit sets a roll bending force for the work rolls 51a and 51b.

(Second pinch roll device)
The second pinch roll device 60 is disposed on the exit side of the inline mill 50. Similar to the first pinch roll device 40, the second pinch roll device 60 includes an upper pinch roll and a lower pinch roll, a rolling load detection device, and a reduction device. Each of the upper pinch roll and the lower pinch roll has a hollow channel formed therein, and is configured to allow a cooling medium (for example, cooling water) to flow therethrough. The pinch roll can be cooled by circulating the cooling medium. For example, the upper pinch roll and the lower pinch roll may have a roll diameter of 400 mm and a roll body length (width) of 2000 mm. Further, the upper pinch roll and the lower pinch roll are arranged via a roll chock in the housing, and are rotationally driven by a motor (not shown). A tension roll 88 is disposed between the inline mill 50 and the second pinch roll device 60.

(Winding device)
The winding device 70 is a device that is disposed on the exit side of the second pinch roll device 60 and winds the cast strip S into a coil shape. A deflector roll 89 is disposed between the second pinch roll device 60 and the winding device 70.

(1-2. Crown control by straightening device)
(1) Control by adjusting the pressing amount of the pressing roll As is conventionally known in straightening devices such as tension levelers, when applying plastic deformation (elongation) by applying tension to the strip, the roll portion of the leveler is adjusted. When the crown shape is used, the pushing amount of the strip becomes large at a portion having a large diameter. Therefore, the tensile tension in the part is larger than that in the other part and is intensively extended, so that the plate thickness of the part is reduced.

  Here, the plate of the casting strip when the initial profile of the cooling drum is processed so that the shape of the plate crown in the steady state has a predetermined parabolic pattern, and the pushing amount of the pushing roll by the straightening device is changed in the steady state. The crown and its elongation were examined. Here, the pushing amount of the pushing roll is based on the height position of the roll axis of the pushing roll when the pushing roll is in contact with the casting strip in a state where the casting strip is stretched linearly in the sheet passing direction. The amount of change in the height position of the roll shaft of the push roll relative to the reference. The pushing amount of the pushing roll in the reference state is set to zero. As the pushing amount increases, the pushing roll is pushed into the casting strip and plastic deformation proceeds more, so that the casting strip passing through the correction device is bent greatly. Here, as an example, the initial profile of the cooling drum was processed so that the difference between the center of the cast strip and the plate thickness (average value at both ends) at a position 75 mm inside from the plate end was a parabolic pattern of 150 μm. At this time, a roll crown of 800 μm / radius was applied to the push roll, and the stress acting on the straightening device was about 15 MPa. The results are shown in FIG.

  As shown in FIG. 4, as the pushing amount of the pushing roll is increased (that is, the moving amount in the pushing direction of the casting strip is increased), the plate crown of the casting strip is decreased and the elongation of the casting strip is increased. At this time, the width of the casting strip is shortened. Due to such interaction, the plate shape (flatness) was not greatly disturbed even when the cast strip was plastically deformed so that the plate crown ratio changed. It was also found that the relationship between the pushing amount of the pushing roll and the plate crown was almost linear as shown in FIG. In addition, although elongation occurs, the thickness of the cast strip decreases, but the final thickness is made by an in-line mill, so the influence of the thickness change of the cast strip in the straightening device can be ignored. Therefore, it is preferable that the correction device according to the present embodiment is installed upstream of the in-line direction with respect to the in-line mill.

  Therefore, the inventor of the present application has found that the plate crown of the casting strip can be reduced by changing the pushing amount of the pushing roll, and in the continuous casting equipment provided with the twin drum type continuous casting apparatus, the heat of the cooling drum is obtained. In order to control the plate crown of the cast strip S caused by the influence, the correction device 80 is provided, and it has been conceived that the pressing amount of the pressing roll is controlled in accordance with the time series change of the plate crown shape of the cast strip S. Thereby, the plate crown of the cast strip S when passing through the straightening device 80 can be appropriately corrected, and the plate crown change of the cast strip S rolled by the in-line mill 50 can be prevented.

  Specifically, the correction device 80 first sets the position of the roll shaft of the roll 81B, which is a push roll, to an initial position calculated in advance through experiments or the like at the start of casting. The initial position of the roll shaft may be a position for causing the size of the plate crown of the cast strip S to be a preset target value, for example.

  After that, when the tip of the casting strip S starts to pass through the in-line mill 50, the pressing roll is turned on the basis of the relationship between the pressing amount of the pressing roll and the size of the plate crown of the casting strip S according to the time-series change of the plate crown. The pushing amount of a certain roll 81B is controlled. For the relationship between the pressing amount of the pressing roll and the size of the plate crown of the casting strip S, a relationship obtained by an experiment or the like as shown in FIG. 4 may be used. The control device calculates the plate crown of the cast strip S based on the plate thickness of the cast strip S measured by the plate profile meters 91 and 93, for example. The shape of the casting strip S rolled by the in-line mill 50 is adjusted by adjusting the pushing amount of the pushing roll in accordance with the shape of the plate crown of the casting strip passing through the in-line mill 50, that is, the size of the plate crown. Can be made uniform. As a result, it is possible to prevent the disorder of the plate shape in the subsequent cold rolling, improve the plate thickness accuracy in the plate width direction of the product, and improve the yield.

  In the steady state, the pushing amount of the pushing roll may be less than 0 mm where the casting strip S is not bent. Alternatively, the rolls 81A, 81B, 81C of the straightening device 80 are not driven, but may slip and cause wrinkles in the casting strip S. Therefore, in order to prevent the casting strip S from being wrinkled, the rolls 81A, 81B, 81C may be used as drive rolls. Further, the initial profile of the cooling drums 10a and 10b may be corrected in consideration of the crown change caused by the amount of pressing of the roll 81B, which is a pressing roll, as long as the amount of slip does not occur. Further, the sheet crown of the casting strip S may be measured on the entry side of the straightening device 80, and the pushing amount of the pushing roll may be controlled based on the measurement result. You may measure a crown and control the pushing amount of a pushing roll based on a measurement result. Of course, the pushing amount of the pushing roll may be controlled based on the crown of the casting strip S measured on the entry side and the exit side of the straightening device 80.

(2) Control by adjustment of roll crown of push roll In addition, in the continuous casting equipment according to the present embodiment, when the plate crown of the cast strip is controlled by the straightening device 80, the push roll push amount calculated in advance through experiments or the like The shape of the roll crown of the push roll may be changed based on the relationship with the plate crown change amount. Even if the pushing amount of the pushing roll is the same, if the size of the roll crown of the pushing roll is different, the size of the plate crown to be corrected thereby changes. Therefore, the size of the roll crown of the push roll may be changed to control the plate crown to have a desired size. The size of the roll crown of the push roll can be changed, for example, by changing the hydraulic pressure of the hydraulic chamber in the push roll, or by providing a plurality of block bodies in the roll width direction that have a higher thermal expansion coefficient than the roll material. Each may be heated individually. Furthermore, a roll profile can be changed also by providing a plurality of pressurization devices in the roll width direction in the roll and individually pressurizing the pressurization devices.

  The adjustment of the roll profile at the time of contact with the roll 81B, which is a push roll, is performed, for example, by providing a hydraulic chamber inside the roll 81B and changing the hydraulic pressure of the hydraulic chamber so that the roll profile becomes asymmetric in the plate width direction. You may go. Alternatively, a plurality of block bodies having a higher thermal expansion coefficient than the roll material may be provided inside the roll 81B in the plate width direction, and the roll profile during contact may be changed by individually heating the block bodies. Furthermore, a plurality of pressure devices may be provided in the width direction of the plate inside the roll 81B, and the pressure profile at the time of contact may be changed by individually pressing the pressure devices.

  FIG. 5 shows an example of the relationship between the pushing amount of the pushing roll and the plate crown changing amount when the roll crown of the pushing roll is changed. The plate crown change amount is a change amount from the plate crown in the reference state, that is, when the pushing amount is zero. As shown in FIG. 5, when the push-in amount of the push roll is the same, the plate crown change amount increases as the roll crown of the push roll increases. That is, the control capability of the plate crown improves as the roll crown of the push roll increases. When the push-in amount is zero, the plate crown change amount is zero regardless of the roll crown size, and the plate crown control capability is zero. When the push roll is a flat roll without a roll crown, even if the push amount is increased, the plate crown change amount does not change so much and the plate crown control capability is small.

  In addition, although the correction | amendment apparatus which has the pushing roll of 1 step | paragraph structure was demonstrated here, it cannot be overemphasized that the same effect will be acquired if the roll profile of the roll which contacts a casting strip is a convex type fundamentally. Therefore, the configuration of the push roll of the straightening device may be multistage. The same effect can be obtained even if the roll profile of the push roll is changed in a pseudo manner. For example, the pressing roll of the straightening device has a two-stage structure, the roll profile of the pressing roll that contacts the casting strip is flat, and is provided on the upper side of the pressing roll (that is, opposite to the casting strip) and contacts the pressing roll. The roll profile of the supporting auxiliary roll is made a convex profile. Then, the roll profile of the pushing roll that is in contact with and supported by the auxiliary roll having the convex profile becomes a pseudo convex shape corresponding to the convex profile of the auxiliary roll. Thus, the roll crown of the push roll may be changed by making the roll profile of the push roll pseudo-convex.

  Based on the relationship between the roll crown of the push roll and the plate crown change amount, the push crown push amount is changed by changing the roll crown of the push roll in accordance with the temporal change of the plate crown shape of the casting strip S. Can be changed. For example, the roll on the side in contact with the cast strip having a two-stage structure is easily bent with a small diameter, and the roll supporting the small diameter roll is made larger in diameter than the small diameter roll. Then, the large diameter roll is divided in the width direction to change the distribution of the pushing amount of the divided roll (that is, the pushing amount at the center of the plate width is made larger than the end portion), or the small diameter roll is supported. A large-diameter roll is provided with a hydraulic chamber to increase the hydraulic pressure, and the central part of the plate width is expanded to form a convex crown. The small-diameter roll profile on the side in contact with the casting strip S may be changed by placing the small-diameter roll along the large-diameter roll having the roll profile thus changed.

  As a result, it is possible to appropriately correct the plate crown of the cast strip S when passing through the straightening device 80 by controlling the roll crown of the push roll, and the plate crown of the cast strip S rolled by the in-line mill 50. Changes can be prevented. In addition, you may perform plate | board crown control of the casting strip S by both adjustment of the pushing amount of the above-mentioned pushing roll, and adjustment of a roll crown.

(1-3. Production of cast strip)
Hereinafter, the manufacture of the cast strip S in the cast strip manufacturing process 1 shown in FIG. 1 will be described.

  First, the molten metal is temporarily stored in the tundish T. The molten metal stored in the tundish T is injected into the molten metal storage portion 15 of the twin-drum continuous casting apparatus 10 through a nozzle formed in the lower part of the tundish. At this time, the amount of the molten metal stored in the molten metal storage unit 15 is controlled to be constant by controlling the nozzle.

  Next, while rotating the pair of cooling drums 10a and 10b, the molten metal stored in the molten metal storage unit 15 is solidified and grown on the peripheral surfaces of the pair of cooling drums 10a and 10b, thereby casting the casting strip S. When casting is started in the twin-drum type continuous casting apparatus 10, for example, as shown in FIG. 2, the dummy sheet 11 is connected to a portion that becomes the tip of the casting strip S. At this time, a dummy bar 13 that is much thicker than the casting strip S is provided at the leading end side in the traveling direction of the dummy sheet 11, and the connecting portion between the casting strip S and the dummy sheet 11 is larger than the thickness of the casting strip S. A thick protrusion 12 is formed. For example, the dimensions of the cast strip S may be 2 mm in thickness and 1260 mm in width, and the peripheral speed (casting speed) of the pair of cooling drums 10a and 10b may be 150 m / min. However, the dimensions of the casting strip S and the casting speed are not limited to this example.

  The casting strip S formed by the pair of cooling drums 10a and 10b is subjected to an antioxidant treatment in the antioxidant device 20 as necessary. Then, the casting strip S is conveyed downstream by the feed roll 87 while keeping the loop length of the casting strip S between the cooling drums 10a and 10b and the feed roll 81 constant. Moreover, the casting strip S is cooled with the cooling device 30 as needed. Thereafter, the casting strip S is moved to the downstream side via the straightening device 80 while tension is generated between the first pinch roll device 40 and the in-line mill 50 by the first pinch roll device 40. Send to inline mill 50. At this time, the amount of pressing of the roll 81B of the straightening device 80 is the size of the plate crown of the casting strip calculated in advance by experiments or the like until the flying touch by the in-line mill 50 is started (that is, at the start of casting). The target value is set.

  The inline mill 50 starts a flying touch after the protrusion 12 has passed through the inline mill 50. That is, a rolling force is applied while synchronizing the roll speed of the in-line mill 50 with the plate speed of the cast strip S, the cast strip S is rolled and adjusted to a desired plate thickness. Here, when the tip of the casting strip S begins to pass through the in-line mill 50, the correction device 80, based on the relationship between the pressing amount of the pressing roll and the plate crown of the casting strip, according to the time system change of the plate crown, The pushing amount of the roll 81B is controlled. For example, when the rolling force of the in-line mill 50 becomes equal to or higher than a predetermined rolling force, the tension between the first pinch roll device 40 and the in-line mill 50 is controlled to a predetermined tension, and the roll 81B of the correction device 80 is used. Is controlled to adjust the plate crown to a desired value. Note that the plate crown may be controlled by adjusting the roll profile of the roll 81B instead of the push amount of the roll 81B, or the plate crown may be controlled by adjusting the push amount of the roll 81B and its roll profile.

  The casting strip S rolled by the in-line mill 50 is wound by the second pinch roll device 60 while a tension is generated between the in-line mill 50 and the second pinch roll device 60 by the second pinch roll device 60. It is conveyed to. The winding device 70 winds up the cast strip S that has been conveyed.

  Heretofore, the continuous casting equipment having the twin drum type continuous casting apparatus according to the first embodiment of the present invention and the method for controlling the plate crown of the casting strip S have been described.

<2. Second Embodiment>
Next, a method for controlling the crown of a cast strip according to a second embodiment of the present invention will be described. The plate crown control of the cast strip according to the present embodiment is effective when there is a temperature distribution in the plate width direction of the cast strip, and is symmetrical even if the cast strip has an asymmetric temperature distribution in the plate width direction. Can be secured. For this reason, in this embodiment, a temperature distribution measuring device for measuring the temperature distribution in the plate width direction of the cast strip is provided on the upstream side or the downstream side of the correction device for the casting strip manufacturing process described in the first embodiment. Based on the measured temperature distribution in the plate width direction of the cast strip, control is performed so that the indentation amount of the cast strip by the indentation roll becomes asymmetric.

  When there is a temperature distribution in the plate width direction of the cast strip cast by the twin-drum type continuous casting equipment, the plastic deformation at the high-temperature side in the plate width direction proceeds more and is extended much during correction by the straightening device. Assume that the casting strip S is pushed in with the same pushing amount in the plate width direction when one side (left side in FIG. 6) in the plate width direction is high temperature and the other side (right side in FIG. 6) is low temperature. In this case, as shown in the upper side of FIG. 6, the cross-sectional shape of the cast strip S after correction by the correction device is extended more on the high temperature side than on the low temperature side. The extended material also moves in the width direction of the plate, but the plate shape is slightly extended over the edges (the length of the end portion is longer than the length of the center portion of the plate). The cast strip S has an untargeted cross-sectional shape in the plate width direction. As a result, the high temperature side becomes wavy and may cause one-sided elongation and meandering after correction by the straightening device, which leads to shape defects and further meandering during rolling in the subsequent in-line mill, and the cast strip S Furthermore, it becomes easy to fracture.

  As described in the first embodiment, a cooling device is provided on the upstream side of the correction device. It is natural to control so that the temperature distribution in the plate width direction of the casting strip S is eliminated by such a cooling device, but control is performed for a portion where the temperature distribution in the plate width direction has already occurred for the following reason. In some cases, it is difficult to eliminate the temperature distribution in the plate width direction.

  The temperature control of the cast strip in the cooling device is usually performed by controlling the amount of cooling water supplied from a plurality of nozzles arranged in the sheet width direction and the rolling direction. The temperature distribution in the plate width direction of the cast strip is preset controlled by the arrangement of the nozzles, and the amount of cooling water supplied is often constant in the plate width direction. In this case, the temperature distribution in the longitudinal direction of the casting strip is detected, for example, by detecting the temperature at the center of the plate width, and the amount of cooling water supplied from the entire nozzle is controlled so that the temperature becomes a target value. Therefore, even if there is a change in the temperature of the cast strip due to acceleration / deceleration, etc., the temperature is controlled so that the temperature at the center of the plate width becomes the target value, but disturbance (for example, cooling unevenness in the plate width direction of the cooling drum, cooling In order to cope with the temperature distribution in the width direction of the plate due to defects such as twisting of the casting strip due to uneven drum pressure, asymmetrical disturbance such as single wave, clogging of part of the nozzle, etc. Since the temperature control at the end in the plate width direction is not performed, it is difficult to eliminate the temperature distribution in the plate width direction.

  For example, Patent Document 4 discloses a method of controlling a plate profile of a steel plate by a leveler in a hot rolling mill. However, since this technology does not consider the temperature distribution in the plate width direction, the cross-sectional shape of the cast strip after straightening is asymmetric even if it is applied to a straightening device between a twin-drum continuous casting facility and an in-line mill. It is considered that the plate crown becomes one, and one-side elongation and meandering are induced after correction by the correction device.

  Therefore, in the present embodiment, the push amount by the push rolls at a plurality of positions in the plate width direction of the cast strip S is changed according to the temperature distribution in the plate width direction of the cast strip S. As a result, as shown in the lower side of FIG. 6, even when there is a temperature distribution in the plate width direction of the cast strip S, the cast strip S is corrected so as to have a symmetrical shape with respect to the center in the plate width direction. Can do. As a result, the flatness of the cast strip S can be maintained, and it is possible to avoid meandering and plate breakage during subsequent rolling by an in-line mill. Hereinafter, the plate crown control method of the casting strip according to the present embodiment will be described in detail. The casting strip manufacturing process according to this embodiment is substantially the same as the casting strip manufacturing process 1 according to the first embodiment shown in FIG. 1, and is at least one of the upstream side and the downstream side of the straightening device 80. The only difference is that a temperature distribution measuring device is provided on one side. For this reason, in this embodiment, description of the whole structure of a casting strip manufacturing process is abbreviate | omitted.

(2-1. Installation of temperature distribution measuring device)
First, with reference to FIG.7 and FIG.8, the correction apparatus 80 and the temperature distribution measuring apparatuses 95 and 97 of the casting strip manufacturing process which concern on the 2nd Embodiment of this invention are demonstrated. FIG. 7 is an explanatory diagram showing the installation position of the temperature distribution measuring device with respect to the correction device according to the present embodiment. FIG. 8 is an explanatory diagram for explaining a temperature distribution measuring method in the plate width direction by the temperature distribution measuring apparatus.

  The casting strip manufacturing process according to the present embodiment is similar to the first embodiment shown in FIG. 1 in that the tundish (storage device) T, the twin drum continuous casting equipment 10, the antioxidant device 20, and the cooling device. 30, a first pinch roll device 40, an inline mill 50, a second pinch roll device 60, a winding device 70, and a correction device 80. Furthermore, in this embodiment, as shown in FIG. 7, temperature distribution measuring devices 95 and 97 for measuring the plate temperature distribution in the plate width direction of the casting strip S on the upstream side and the downstream side in the casting direction with respect to the correction device 80. Is provided. In FIG. 7, temperature distribution measuring devices 95 and 97 are provided on the upstream side and the downstream side in the casting direction of the straightening device 80, but the present invention is not limited to such an example. The temperature distribution measuring device may be provided on at least one of the upstream side and the downstream side in the casting direction of the correction device 80.

  The temperature distribution measuring devices 95 and 97 are configured to be able to measure temperatures at at least three measurement positions in the plate width direction in order to measure the temperature distribution in the plate width direction of the casting strip S. Specifically, as shown in FIG. 8, for example, the temperature distribution measuring device 95 may be configured from at least three plate thermometers 95a, 95b, and 95c arranged fixed in the plate width direction of the casting strip S. . In this case, it is desirable that the plate thermometers 95a, 95b, and 95c are disposed at the center of the plate width of the casting strip S and in the vicinity of both ends of the plate width. Alternatively, the temperature distribution measuring device may be composed of one plate thermometer 95d that is movable in the plate width direction of the casting strip S. The temperature distribution of the cast strip S can be measured by reciprocating the movable plate thermometer 95d in the plate width direction. Since the casting strip S moves in the casting direction even during temperature measurement by the plate thermometer 95d, the measurement position by the plate thermometer 95d is skewed. Therefore, although it is not a precise temperature distribution in the plate width direction, the influence on the plate crown control according to the present embodiment is a deviation that can be ignored.

  Instead of the plate thermometer, a temperature distribution measuring device that measures a temperature distribution on a plane such as a thermoviewer may be used as the temperature distribution measuring device. Also in this case, the temperature of the surface of the casting strip S can be measured as a two-dimensional temperature distribution. However, this method slightly increases the measurement time and calculation time compared to the case of using a plate thermometer.

(2-2. Plate crown control considering temperature distribution in the plate width direction)
In the plate crown control according to the present embodiment, the temperature distribution measuring devices 95 and 97 measure the temperature distribution in the plate width direction of the cast strip S, and based on the measured temperature distribution, the roll that is the pressing roll of the straightening device 80 Each push amount in the plate width direction of 81B is controlled. Here, the temperature distribution in the plate width direction of the strip S is used to correct the cast strip S based on the relationship between the temperature distribution in the plate width direction of the cast strip S and the cross-sectional shape of the cast strip S after correction by the correction device 80. I thought about the effect. First, in order to investigate the influence of the temperature distribution on the correction of the casting strip S, the flow distribution in the plate width direction from the spray of the cooling device was adjusted, and the casting strip S was provided with a temperature distribution in the plate width direction. Then, five positions in the plate width direction of the cast strip S (specifically, when the center in the plate width direction is 0 and normalized by −1.0 to 1.0, ± 0.9, ± 0.5) , 0 position), a fixed plate thermometer was installed, and the temperature at that location was measured.

And based on the measurement result of each plate thermometer of a temperature distribution measuring apparatus, the temperature distribution T (x) of the casting strip S was approximated by a quadratic equation. Specifically, the temperature distribution T (x) of the casting strip S is represented by a quadratic expression T (x) = ax ² + bx + c. Here, x represents a position in the plate width direction. x may be a normalized value (value divided by the half plate width). When standardized, as described above, the center of the plate width is 0, the plate end on one side is represented by -1, and the plate end on the other side is represented by +1. The coefficients a, b, and c in the above quadratic expression are constants obtained by regression approximation. The constant b indicates an asymmetric component of the temperature distribution of the casting strip S, and is also referred to as “temperature asymmetry parameter b” below. The constant c indicates the temperature at the center of the plate width of the casting strip S.

  As an example, for the case of the roll crown of 500 μm in FIG. 5 shown in the first embodiment and the push-in amount of 6 mm, the arithmetic units (not shown) obtain the constants b and c of the above quadratic formula, Plate crown difference (difference between the plate crown on one side and the plate crown on the other side. When the plate crown difference is 0, the plate crown is symmetrical). FIG. 9 shows the relationship between the temperature asymmetry parameter b and the plate crown difference in such a case.

  From FIG. 9, it was found that the plate crown difference increases as the temperature asymmetry parameter b increases, even with the same pressing amount. It was also found that even if the value of the temperature asymmetry parameter b is the same, the plate crown difference increases as the plate temperature (c) increases. Therefore, by adjusting the indentation amount in the sheet width direction (for example, both ends in the sheet width direction) of the indentation roll based on the value b of the temperature asymmetry parameter and the sheet temperature c, the casting strip S corrected by the correction device 80 is adjusted. The cross-sectional shape (in other words, plate crown, plate profile) can be made symmetric. In operation, the variation in the plate center temperature of the cast strip is small and can be ignored. Therefore, based on the temperature asymmetry parameter b, when the temperature distribution is in the plate width direction, the pushing amount on the high temperature side is compared with the low temperature side. Each push amount in the plate width direction may be adjusted so as to make it smaller. When the plate temperature c is outside the allowable range, such as when the plate temperature c deviates more than the target value, the plate temperature c is also taken into account to adjust each push amount in the plate width direction of the push roll. The plate crown can be controlled appropriately and accurately.

  From this knowledge, in the present embodiment, in a continuous casting facility provided with a twin-drum type continuous casting device, a straightening device 80 is provided to control the plate crown of the casting strip S caused by the thermal effect of the cooling drum, and the casting strip S The pushing amount of the pushing roll is controlled according to the temperature asymmetry (temperature asymmetry parameter b) in the plate width direction. Thereby, the plate crown of the cast strip S when passing through the straightening device 80 can be appropriately corrected so that the cross-sectional shape is symmetric, and the plate crown change of the cast strip S rolled by the in-line mill 50 can be corrected. Can be prevented. Needless to say, the plate crown itself associated with the thermal expansion of the cooling drums 10a and 10b is determined by the pressing amount based on the method described in the first embodiment and controlled by the pressing amount.

  Specifically, first, the correction device 80 assumes that the temperature asymmetry parameter b is 0 as an initial setting, and obtains a plate crown that is symmetric in the target plate width direction. The position of the roll shaft of a certain roll 81B may be set to an initial position calculated in advance through experiments or the like. At this time, the pushing amount of the pushing roll at both ends in the plate width direction may be the same.

  Next, when the tip of the casting strip S begins to pass through the in-line mill 50, the pressing roll is moved by the pressing roll based on the relationship between the pressing amount of the pressing roll and the size of the plate crown of the casting strip S according to the time system change of the plate crown. The pushing amount of a certain roll 81B is controlled. As described in the first embodiment, the relationship between the pressing amount of the pressing roll and the size of the plate crown of the casting strip S is obtained by using a relationship obtained by an experiment as shown in FIG. Also good. The control device calculates the plate crown of the cast strip S based on the plate thickness of the cast strip S measured by the plate profile meters 91 and 93, for example. Then, by adjusting the pushing amount of the pushing roll according to the shape of the plate crown of the casting strip S passing through the inline mill 50, that is, the size of the plate crown, the casting strip S rolled by the inline mill 50 is adjusted. The shape can be made uniform.

  At this time, in this embodiment, the temperature distribution of the casting strip S is further measured by the temperature distribution measuring device, and the pressing amount of the pressing rolls at both ends in the plate width direction is determined based on the temperature asymmetry parameter b obtained from the result. Will be corrected. For the correction amount, for example, a relationship obtained by an experiment as shown in FIG. 9 may be used. The asymmetric control will be briefly described below, in which the casting strip S is rectangular, and the crown change (symmetric crown change) of the casting strip S due to the pressing by the pressing roll is omitted.

For example, as shown in FIG. 10, when there is a temperature distribution in which the one side is hot and the other side is cold in the plate width direction of the cast strip S to be straightened by the roll 81B of the straightening device 80, the cast strip S as shown in the upper side of FIG. Is uniformly pressed in the plate width direction. Both ends of the roll shaft of the roll 81B is respectively depression depth [delta] _1. In this way, when the casting strip S having a temperature distribution in the plate width direction is uniformly pressed in the plate width direction, extension occurs on the high temperature side. As a result, the cross-sectional shape of the cast strip S after correction by the roll 81B becomes an asymmetric cross-sectional shape in which the plate thickness on the high temperature side is smaller than the plate thickness on the low temperature side.

Therefore, as shown in FIG. 10 lower roll profile (the roll profile upon contact), the high-temperature side of the roll 81B as compared to the depression depth [delta] ₂ of the low temperature side when the cast strip S is in contact with the rolls 81B It adjusts so that pushing amount (delta) _{3 of} may become small. Thereby, the cross-sectional shape of the cast strip S after correction by the roll 81B can be corrected so as to be symmetric in the plate width direction. As a result, it is possible to prevent plate shape disturbance in cold rolling with an in-line mill, improve the plate thickness accuracy in the plate width direction (symmetry of plate crown and plate crown), and improve yield. It is also possible to prevent shape defects, meandering and plate breakage in an in-line mill.

  The adjustment of the roll profile at the time of contact with the roll 81B, which is a push roll, is performed, for example, by providing a hydraulic chamber inside the roll 81B and changing the hydraulic pressure of the hydraulic chamber so that the roll profile becomes asymmetric in the plate width direction. You may go. Alternatively, a plurality of block bodies having a higher thermal expansion coefficient than the roll material may be provided inside the roll 81B in the plate width direction, and the roll profile during contact may be changed by individually heating the block bodies. Furthermore, a plurality of pressure devices may be provided in the width direction of the plate inside the roll 81B, and the pressure profile at the time of contact may be changed by individually pressing the pressure devices.

  Alternatively, instead of configuring the push roll in a single stage like the roll 81B of FIG. 7, the roll 81B that is the push roll is a flat roll, and contacts the roll 81B above the roll 81B (on the opposite side to the casting strip S). It is good also as a 2 step | paragraph structure which provides the auxiliary roll to support. Specifically, for example, as illustrated in FIG. 11, an auxiliary roll 110 including a plurality of divided rolls 111 to 115 is provided above the roll 81 </ b> B in the plate width direction. The auxiliary roll 110 is configured to be able to be pressed toward the roll 81 </ b> B by the reduction device 120. The reduction device 120 is provided with hydraulic cylinders 121 to 125, for example, in order to press the divided rolls 111 to 115 against the roll 81B independently of each other. With this configuration, according to the temperature distribution in the plate width direction of the casting strip S, the divided rolls 111 to 115 can be reduced by the hydraulic cylinders 121 to 125, and the roll profile during casting of the roll 81B can be changed in a pseudo manner. .

  In this way, by making the roll profile at the time of contact with the cast strip S of the push roll variable, the push amount of the push roll is changed when there is a temperature distribution in the plate width direction of the cast strip S. be able to. As a result, it is possible to appropriately correct the plate crown of the cast strip S when passing through the straightening device 80 by controlling the roll crown of the push roll, and the plate crown of the cast strip S rolled by the in-line mill 50. Changes can be prevented. In addition, you may perform plate | board crown control of the casting strip S by both adjustment of the pushing amount of the above-mentioned pushing roll, and adjustment of a roll crown.

  In the second embodiment, the temperature distribution T (x) of the casting strip S is approximated by a quadratic equation, and the roll profile at the time of contact of the pressing roll is determined based on the temperature asymmetry parameter b of the temperature distribution T (x). It is not limited to such an example, and based on the temperature distribution in the plate width direction of the cast strip S measured by the temperature distribution measuring device, it is based on other parameters representing the temperature asymmetry in the plate width direction of the cast strip S. The roll profile at the time of contact may be determined.

For example, as shown in FIG. 12, the temperature distribution in the plate width direction of the casting strip S is represented by an area, and the pushing amount of the pushing roll in the plate width direction is determined based on the area ratio of the two areas divided into two at the plate width center. May be. That is, the area ratio of the temperature distribution may be used as a parameter representing the temperature asymmetry in the plate width direction. The area ratio of the temperature distribution is defined as an integral temperature asymmetric parameter α. Assuming that two areas divided into two at the center of the plate width are S ₁ and S ₂ , the integral temperature asymmetric parameter α is represented by S ₁ / S ₂ . The integral temperature asymmetric parameter α is 1 when the two areas are the same (that is, when the temperature distribution in the plate width direction is symmetric).

FIG. 12 shows the area of the temperature distribution in the plate width direction of the casting strip S in which one side (left side in FIG. 12) is low in the plate width direction and the other side (right side in FIG. 12) is high. It is an example. When such a cast strip S bisects in plate width center, as shown in FIG. 12, the area S ₁ of the low temperature (left) is smaller than the area S ₂ of the high temperature (right). According to these area ratios, by performing a roll profile at the time of contact of the pressing roll so that the pressing amount on the high temperature side is smaller than that on the low temperature side, the plate of the cast strip S after correction by the correction device 80 as described above. The cross-sectional shape in the width direction can be made symmetric. As a specific example of the calculation method of each area S ₁ , S ₂ , for example, in the case of 3 points (P ₁ , P ₂ , P ₃ ) shown in FIG. You may obtain | require by integrating | accumulating and may obtain | require by trapezoid approximation.

Further, the temperature moment β may be used as a parameter representing the temperature asymmetry in the plate width direction. The temperature moment β is expressed by the following equation (1) using the temperature T _i of the casting strip S at the position of the plate thermometer arranged symmetrically with respect to the center of the plate width and the position x _i at which the plate thermometer is arranged. ). However, the center position of the plate width is set as a reference (zero), one end side (for example, the work side) is set to a positive value, and the other end side (for example, the drive side) is set to a negative value. i is a positive integer indicated by each plate thermometer. Note that the position x _i may be an absolute value, or a normalized position.

β = ΣT _i · x _i (1)

When the temperature distribution in the plate width direction is symmetric, the temperature moment β is zero. In the example shown in FIG. 12 for example, the temperature T ₁ of the cast strip to be measured by the plate thermometer position x ₁ of the cold side, the temperature T ₃ of the cast strip to be measured by the plate thermometers position x ₃ of the high temperature side Based on the above, the temperature moment β is calculated. At this time, the positions x ₁ and x ₃ are represented by standardized positions (−1, +1). When the temperature moment β is calculated based on the above formula (1), the temperature moment β is a positive value because the temperature T ₃ at the position +1 is higher than the temperature at the position −1. Based on this temperature moment β, the pressing amount of the pressing roll in the sheet width direction is determined, and the roll profile at the time of contact of the pressing roll is determined. The cross-sectional shape in the width direction can be made symmetric.

  Thus, the parameter representing the temperature asymmetry in the plate width direction is the coefficient b representing the asymmetric component of the temperature distribution in the quadratic expression representing the temperature distribution in the plate width direction of the casting strip S described in the above embodiment. The temperature asymmetry parameter, the integral temperature asymmetric parameter α, which is the area ratio of the two areas obtained by dividing the area representing the temperature distribution in the plate width direction of the cast strip S by the plate width center, or the plate width center of the cast strip S Two positions symmetrical to each other and a temperature moment β expressed based on the temperature of the casting strip S at the positions can be used.

  Examples relating to the first embodiment of the present invention will be described below. This example was carried out in the manufacturing process of a cast strip having the same configuration as in FIG. The cast strip used in the examples has a plate thickness of 2 mm and a plate width of 1260 mm. The acceleration rate of the cooling drum from the start of casting is 150 m / min / 30 seconds, and the rotational speed of the cooling drum in a steady state is 150 m / min. The initial profile of the cooling drum was processed so that the plate crown of the cast strip was 43 μm in a steady state. In the in-line mill, rolling with a reduction ratio of 30% was performed, and the thickness of the cast strip on the exit side of the in-line mill was 1.4 mm. Rolling in the in-line mill was started 15 seconds after the start of casting (after the dummy sheet passed and the sheet crown of the cast strip became 150 μm or less).

  In Example 1 of the present invention, the relationship between the casting start time and the change in the plate crown of the cast strip was examined in advance. Based on the investigation results, the pushing amount of the pushing roll of the straightening device at each time from the casting start time is set to 43 μm (30 μm after in-line mill rolling) which is the target value of the cast strip after straightening by the straightening device. Pre-set and controlled. Such control was performed 15 seconds after the start of casting, and before that time, the pushing amount of the pushing roll 15 seconds after the start of casting was set. The straightening device was opened after 35 seconds from the start of casting.

  In Example 2 of the present invention, the plate crown of the cast strip is measured before correction by the correction device, and the correction device is pushed so that the target value of the cast strip after correction is 43 μm (30 μm after in-line mill rolling). The roll push-in amount was controlled. This control is performed 15 seconds after the start of casting, and before that, the pushing amount of the pushing roll is adjusted so that the plate crown of the casting strip 15 seconds after the start of casting is obtained by experiments in advance is set to a target value of 43 μm. It was set. The straightening device was opened after 35 seconds from the start of casting.

  In Example 3 of the present invention, the sheet crown of the cast strip is measured after the correction by the correction device, and the pressing roll of the correction device is set to 43 μm (30 μm after in-line mill rolling) which is the target value of the cast strip after correction. The amount of indentation was controlled. Such control is performed 15 seconds after the start of casting, and before that, the pushing amount of the pushing roll is adjusted so that the plate crown of the cast strip obtained 15 seconds after the start of casting is experimentally obtained to a target value of 43 μm. Set. The straightening device was opened after 35 seconds from the start of casting.

  On the other hand, as a conventional example, the straightening device was opened to prevent the cast strip from being stretched, and the sheet was rolled by an in-line mill to a thickness of 1.4 mm.

(Invention Example 1: Leveler preset control)
In Example 1 of the present invention, a slight middle elongation occurred at the start of rolling, but no plate breakage occurred. Further, the plate crown is about 29 to 33 μm at the exit side of the rolling mill at the start of rolling (after 15 seconds from the start of casting), and about 30 μm in the steady state after 30 seconds from the start of casting. It was. Therefore, there was no drop in product yield of the cast strip.

  Further, in Example 1 of the present invention, the same rolling was performed by reducing the flow rate of the cooling water of the cooling drum by 30% as a disturbance change. In this case, the thermal expansion of the cooling drum was faster and larger than when the flow rate was not reduced, and as a result, the plate profile was different from the predicted plate profile change. For this reason, the control accuracy of the plate profile by the pressing amount control of the straightening device is slightly lowered, but it is not problematic. In addition, as disturbance changes other than the above, for example, a cooling change of the cooling drum due to a change in the temperature of the cooling water, a temperature change of the molten metal due to a change in the temperature target value, a change in the casting speed pattern, and the like can be considered. It is estimated that the same result is obtained when these disturbance changes occur.

(Invention Example 2: FF control of leveler)
In Example 2 of the present invention, a slight middle elongation occurred at the start of rolling, but no plate breakage occurred. Further, the plate crown is about 29 to 33 μm at the exit side of the rolling mill at the start of rolling (after 15 seconds from the start of casting), and about 30 μm in the steady state after 30 seconds from the start of casting. It was. Therefore, there was no drop in product yield of the cast strip.

  Furthermore, in Example 2 of the present invention, the same rolling was performed by reducing the flow rate of the cooling water of the cooling drum by 30% as a disturbance change. In this case, the thermal expansion of the cooling drum is faster and larger than when the flow rate is not reduced. In Example 2 of the present invention, the plate profile is measured before correction by the correction device, and the plate profile is controlled by adjusting the pressing amount of the pressing roll based on the result. As a result, it was possible to produce a cast strip with the same high accuracy as when the cooling drum was sufficiently cooled (that is, when the flow rate of cooling water in the cooling drum was not reduced).

  Moreover, in Example 2 of this invention, the roll crown of the pushing roll of a correction apparatus was changed supposing the setting error of the roll crown as disturbance of the correction apparatus itself. At this time, the control amount of the straightening device was calculated using the value before changing the roll crown. In this case, since the pushing amount of the pushing roll for controlling the plate profile was different from that before the roll crown was changed, the control accuracy of the plate profile was slightly lowered, but there was no problem.

(Invention Example 3: Leveler FB Control)
In Example 3 of the present invention, a slight middle elongation occurred at the start of rolling, but no plate breakage occurred. Further, the plate crown is about 29 to 33 μm at the exit side of the rolling mill at the start of rolling (after 15 seconds from the start of casting), and about 30 μm in the steady state after 30 seconds from the start of casting. It was. Therefore, there was no drop in product yield of the cast strip.

  Further, in Example 3 of the present invention, the same rolling was performed by reducing the flow rate of the cooling water of the cooling drum by 30% as a disturbance change. In this case, the thermal expansion of the cooling drum is faster and larger than when the flow rate is not reduced. In Example 3 of the present invention, the plate profile is measured after correction, and the plate profile is controlled by adjusting the pressing amount of the pressing roll based on the result. As a result, it was possible to produce a cast strip with the same high accuracy as when the cooling drum was sufficiently cooled (that is, when the flow rate of cooling water in the cooling drum was not reduced).

  Moreover, in Example 3 of this invention, the roll crown of the pushing roll of a correction apparatus was changed supposing the setting error of the roll crown as disturbance of the correction apparatus itself. At this time, the control amount of the straightening device was calculated using the value before changing the roll crown. In Example 3 of the present invention, the pressing amount of the pressing roll is controlled based on the measurement result of the sheet crown after rolling, so that the accuracy of sheet profile control is higher than that of Examples 1 and 2 of the present invention.

  In Examples 2 and 3 of the present invention, the effectiveness of the present invention was shown by taking the setting error of the roll crown as an example of the disturbance of the correction device itself, but from this result, the setting error of the roll crown of the pushing device is shown. In addition, for example, the case of a roll crown change (roll profile change) due to wear or thermal expansion of the pushing roll can be similarly dealt with.

(Conventional example)
In the conventional example, large middle elongation occurred at the start of rolling, and plate breakage occurred frequently. Further, the plate crown was about 105 μm at the start of rolling (after 15 seconds from the start of casting) on the exit side of the rolling mill, but was about 30 μm in a steady state 30 seconds after the start of casting. Since the plate crown of this product was a target of 30 μm (upper limit of 40 μm), it was possible to use a cast strip after 25 seconds from the start of casting as a product. Moreover, since the remaining molten metal when the plate broke was discarded, the yield was greatly reduced.

  From the above, according to the present invention, during the casting by the twin drum type continuous casting device, the plate crown of the casting strip is controlled by using the straightening device, so that stable rolling without plate breakage and the plate in the plate width direction can be achieved. It was confirmed that it was possible to manufacture a product with high thickness accuracy.

  Examples relating to the second embodiment of the present invention will be described below. This example was implemented in the manufacturing process of the cast strip provided with the structure demonstrated in 2nd Embodiment. The cast strip used in the examples has a plate thickness of 2 mm and a plate width of 1260 mm. The acceleration rate of the cooling drum from the start of casting is 150 m / min / 30 seconds, and the rotational speed of the cooling drum in a steady state is 150 m / min. The initial profile of the cooling drum was processed so that the plate crown of the cast strip was 43 μm in a steady state. In the in-line mill, rolling with a reduction ratio of 30% was performed, and the thickness of the cast strip on the exit side of the in-line mill was 1.4 mm. Rolling in the in-line mill was started 15 seconds after the start of casting (after the dummy sheet passed and the sheet crown of the cast strip became 150 μm or less).

  In the present invention example, an experiment was conducted in advance to investigate the relationship between the casting start time and the change in the crown of the cast strip. Based on the investigation results, the pushing amount of the pushing roll of the straightening device at each time from the casting start time so as to be 43 μm (30 μm after in-line mill rolling) which is the target value of the cast strip after straightening by the straightening device ( (Symmetric component) was previously set and controlled. Further, the temperature distribution in the plate width direction of the cast strip measured by the temperature distribution measuring device provided upstream of the straightening device is approximated by a quadratic equation to obtain the temperature asymmetry parameter b. The pushing amount on both sides of the straightening device was controlled so as to be symmetrical. Such control was performed 15 seconds after the start of casting, and before that time, the pushing amount of the pushing roll 15 seconds after the start of casting was set.

  On the other hand, as a conventional example, an experiment was performed in advance to investigate the relationship between the casting start time and the change in the plate crown of the casting strip. Based on the investigation results, the pushing amount of the pushing roll of the straightening device at each time from the casting start time so as to be 43 μm (30 μm after in-line mill rolling) which is the target value of the cast strip after straightening by the straightening device ( (Symmetric component) was previously set and controlled. No information on the plate temperature distribution measuring equipment installed upstream of the straightening device was used. Such control was performed 15 seconds after the start of casting, and before that, the pushing amount of the pushing roll 15 seconds after the start of casting was set.

  About this invention and the prior art example, the casting operation was performed 500 times (a total of 1000 times), and the distribution of the sheet crown difference after rolling in the in-line mill and the number of breaks due to meandering in the in-line mill were examined. In the present invention, the plate crown difference was 90% or more within 30 μm ± 5 μm, whereas in the conventional example, the plate crown difference was 90% or more within 30 μm ± 15 μm. In the conventional example, only about 28% was within 30 μm ± 5 μm. Further, the plate breakage due to meandering and shape failure in the in-line mill was once in the present invention and 18 times in the conventional example.

  From the above, according to the present invention, during the casting by the twin drum type continuous casting device, the plate crown of the casting strip is controlled by using the straightening device, so that stable rolling without plate breakage and the plate in the plate width direction can be achieved. It was confirmed that it was possible to manufacture a product with high thickness accuracy, that is, a product having a plate crown difference and a symmetrical shape in the plate width direction.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Casting strip manufacturing process 10 Twin drum type continuous casting apparatus 10a, 10b Cooling drum 11 Dummy sheet 12 Protrusion part 13 Dummy bar 15 Molten metal storage part 20 Antioxidation apparatus 30 Cooling apparatus 40 1st pinch roll apparatus 40a, 40b Pinch roll 50 Inline mill 51a, 51b Work roll 52a, 52b Intermediate roll 53a, 53b Backup roll 60 Second pinch roll device 70 Winding device 80 Straightening device 81A, 81B, 81C Roll 83A, 83B, 83C Roll chock 85A, 85B, 85C Housing 86 Lifting mechanism 88 Tension roll 89 Deflector roll 91, 93 Plate profile meter 95, 97 Temperature distribution measuring device 95a, 95b, 95c, 95d Plate thermometer 100 Auxiliary roll mechanism 110 Auxiliary Lumpur 111 to 115 divided rolls 120 reduction device 121-125 hydraulic cylinder

Claims (17)

A twin-drum continuous casting apparatus that forms a molten metal storage part by a pair of cooling drums and side weirs, and casts the molten metal stored in the molten metal storage part while rotating the pair of cooling drums;
A rolling device that is arranged on the downstream side in the casting direction of the twin drum type continuous casting device and rolls the cast slab;
The push roll is disposed between the twin-drum type continuous casting apparatus and the rolling apparatus, and the push roll is moved up and down with respect to the push roll having at least a convex roll profile and the cast piece in tension in the casting direction. A straightening device having a lifting mechanism for correcting the shape of the slab,
A continuous casting facility.   The continuous casting equipment according to claim 1, wherein the roll profile of the push roll is configured to be changeable.   The continuous casting equipment according to claim 2, wherein the push roll is a roll profile variable roll in which the roll profile can be controlled by supplying and discharging a pressure medium to and from a pressurizing chamber disposed therein.   The continuous casting equipment according to claim 2 or 3, wherein the roll profile of the push roll is changed based on a relationship between a casting start time calculated in advance and a size of a plate crown of the slab.   The pushing amount of the pushing roll by the lifting mechanism is set based on a relationship between a casting start time calculated in advance and a size of a plate crown of the slab, according to any one of claims 1 to 4. Continuous casting equipment. A plate thickness measuring device for measuring the plate thickness of the slab is provided on at least one of the upstream side and the downstream side in the casting direction with respect to the correction device,
The plate thickness measuring device measures the plate thickness at two locations including at least the plate width center in the plate width direction of the slab,
The continuous casting equipment according to any one of claims 1 to 5, wherein a plate crown of the slab is calculated based on the measured plate thickness and measurement position.   6. The continuous casting equipment according to claim 5, wherein at least one of the pushing amount of the pushing roll and the roll profile by the lifting mechanism is set based on the calculated plate crown of the slab.   8. The temperature distribution measurement device according to claim 1, further comprising a temperature distribution measuring device that measures the temperature in the plate width direction of the slab on at least one of the upstream side and the downstream side in the casting direction with respect to the correction device. Continuous casting equipment described in The temperature distribution measuring device comprises at least three plate thermometers arranged in the plate width direction of the slab,
The continuous casting equipment according to claim 8, wherein the plate thermometer is disposed at least in the center of the plate width of the slab and in the vicinity of both ends of the plate width.   The continuous casting equipment according to claim 8, wherein the temperature distribution measuring device includes a plate thermometer movable in a plate width direction of the slab. A twin-drum continuous casting apparatus that forms a molten metal storage part by a pair of cooling drums and side weirs, and casts the molten metal stored in the molten metal storage part while rotating the pair of cooling drums; A rolling device for rolling the cast slab disposed on the downstream side in the casting direction of the drum type continuous casting device, and a plate crown of the slab cast by the twin drum type continuous casting device A control method,
The continuous casting equipment is disposed between the twin-drum type continuous casting apparatus and the rolling apparatus, and has a pressing roll having at least a convex roll profile and the slab in a state of being tensioned in a casting direction. An elevating mechanism that elevates and lowers the push roll, and includes a correction device that corrects the shape of the slab,
Based on the relationship between the casting start time calculated in advance and the size of the plate crown of the slab, the elevating mechanism according to the plate crown of the slab that changes in time with the passage of time from the casting start time. And a crown control method for changing the pushing amount of the pushing roll. The pushing amount of the pushing roll is
At the start of casting, it is set to a first indentation amount with the plate crown of the slab as a target value,
After the slab is bitten in the rolling device, the slab changes in accordance with the plate crown of the slab passing through the correction device based on the relationship between the pressing amount of the pressing roll and the plate crown acquired in advance. The plate crown control method according to claim 11. The pushing amount of the pushing roll is
At the start of casting, it is set to a first indentation amount with the plate crown of the slab as a target value,
After the slab is bitten in the rolling device, the slab changes according to the plate crown of the slab passing through the straightening device based on the previously acquired relationship between the roll profile of the push roll and the plate crown. The method for controlling a crown of a plate according to claim 11 or 12. The continuous casting facility further includes a temperature distribution measuring device that measures the temperature in the plate width direction of the slab on at least one of the upstream side and the downstream side in the casting direction with respect to the correction device,
Based on the temperature distribution in the plate width direction of the slab measured by the temperature distribution measuring device, calculate a parameter representing the temperature asymmetry in the plate width direction of the slab,
The roll profile at the time of contact when the pushing roll is in contact with the slab is determined based on the relationship between the parameter of the slab calculated in advance and the size of the plate crown. The plate crown control method according to claim 1.   As a parameter representing the temperature asymmetry in the sheet width direction of the slab, a temperature asymmetric parameter that is a coefficient representing an asymmetric component of the temperature distribution in a quadratic expression representing the temperature distribution in the sheet width direction of the slab, the slab An integral temperature asymmetric parameter which is an area ratio of two areas obtained by dividing an area representing the temperature distribution in the sheet width direction into two at the sheet width center, or two positions symmetrical to the sheet width center of the slab, and The plate crown control method according to claim 14, wherein any one of temperature moments expressed based on the temperature of the slab at the position is used.   The contact roll profile of the push roll is changed by changing the roll profile in the axial direction of the push roll or by adjusting the push amount of the push roll into the slab at a plurality of push positions in the axial direction. The plate crown control method according to claim 14 or 15.   The said push roll is moved so that it may be in the state which does not press the said slab by the said raising / lowering mechanism, when the plate crown of the said slab becomes a steady state. Plate crown control method.

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