Rolling mill exit shape control system and rolling mill

Abstract

A strip shape control system for a rolling mill includes a rolling mill, a strip shape measuring device, a controller, and a processor. The mill's roll set is used to roll the steel strip passing between the two rolls. A central pressure device applies a central bending moment force to the central portion of the two rolls in the approach direction, and an edge pressure device applies an edge bending moment force to the edge portion of the two rolls in the separation direction. The strip shape measuring device is connected to the rolling mill to measure and generate strip shape measurement data. The processor is connected to the rolling mill, the strip shape measuring device, and the controller to calculate the strip shape based on the measurement data and adjust the pressure weights of the central and edge pressure devices accordingly, thereby instructing the controller to control the edge and central pressure devices.

Description

Rolling mill discharge plate shape control system and rolling mill ROLLING MILL EXIT SHAPE CONTROL SYSTEM AND ROLLING MILL Technical Field

[0001] This disclosure relates to strip shape control, and more particularly to a strip shape control system for rolling mill output and the rolling mill itself. Prior Technology

[0002] Current four-roll cold rolling mills have poor performance in controlling the strip shape of specific strips. For example, they cannot automatically control the production of strips with micro-center buckles but relatively no wavy edges; some automatically controlled products have excessive center buckles, leading to scratches or unevenness during the stringing process; or they cannot automatically produce micro-edge buckles for specific products, resulting in the inability to burn off surface contaminants during the stringing process. Therefore, it is necessary to be able to finely control the strip shape to obtain the target product. In addition, manually measuring the strip shape and then adjusting it by the mill according to empirical rules is time-consuming and labor-intensive. This not only easily causes mental burden on the workers, but may also make it difficult to make timely and accurate adjustments, and may cause material loss due to multiple adjustments. Therefore, a precise control solution that can save labor costs is needed. Summary of the Invention

[0003] This disclosure proposes a strip shape control system for a rolling mill, comprising a rolling mill, a strip shape measuring device, a controller, and a processor. The rolling mill includes a first roll group, a first central pressure device, and a first edge pressure device. The first roll group is used to roll the steel strip passing between the two rolls of the first roll group. The first central pressure device is connected to the first roll group and applies a first central bending moment force to the central portion of the two rolls in the approach direction. The first edge pressure device is connected to the first roll group and applies a first edge bending moment force to the edge portion of the two rolls in the separation direction. The controller is connected to the rolling mill and controls the first central pressure device and the first edge pressure device. The strip shape measuring device is connected to the rolling mill and measures and generates strip shape measurement data after rolling. The processor is connected to the rolling mill, the shape measurement device and the controller. The processor is used to calculate the shape based on the shape measurement data and adjust the pressure weights of the first central pressure device and the first edge pressure device accordingly. The processor also controls the first central pressure device and the first edge pressure device according to the pressure weights.

[0004] In one embodiment, the processor is further configured to instruct the first working roll group to be replaced with a second working roll group whose working roll crown is greater than that of the first working roll group when the plate shape has an undesirable slope.

[0005] In one embodiment, the processor is further configured to increase the pressure weight of the first edge pressure device when an undesirable slope occurs in the plate shape, thereby instructing the controller to control the first edge pressure device to increase the first edge bending moment force.

[0006] In one embodiment, the processor is further configured to reduce the pressure weight of the first central pressure device when the plate shape exhibits excessively large mid-wave, thereby instructing the controller to control the first central pressure device to reduce the first central bending moment force.

[0007] In one embodiment, the processor is further configured to increase the pressure weight of the first edge pressure device when the plate shape exhibits excessive medium wave, thereby instructing the controller to control the first edge pressure device to increase the first edge bending moment force.

[0008] In one embodiment, the rolling mill further includes a second central pressure device and a second edge pressure device. The second central pressure device is connected to the first work roll group and is used to apply a second central bending moment force to the central portion of the two work rolls in an approach direction, which is farther away from the central portion compared to the first central pressure device. The second edge pressure device is connected to the first work roll group and is used to apply a second edge bending moment force to the edge portion of the two work rolls in a separation direction, which is closer to the central portion compared to the first edge pressure device. The processor is further used to determine the pressure application weights of the second central pressure device and the second edge pressure device according to the strip shape, and to control the second central pressure device and the second edge pressure device according to the pressure application weight instruction controller.

[0009] In one embodiment, the processor is further configured to increase the pressure weights of the first edge pressure device and the second edge pressure device respectively when the plate shape has an undesirable slope, so as to instruct the controller to control the first edge pressure device to increase the first edge bending moment force and control the second edge pressure device to increase the second edge bending moment force, wherein the pressure weight of the first edge pressure device is greater than that of the second edge pressure device.

[0010] In one embodiment, the control module is further configured to reduce the pressure weights of the first central pressure device and the second central pressure device when the plate shape has excessively large medium waves, so as to control the first central pressure device to reduce the first central bending moment force and control the second central pressure device to reduce the second central bending moment force, wherein the pressure weight of the first central pressure device is less than that of the second central pressure device.

[0011] In one embodiment, the pressure weight is an adjustment factor of the first edge bending moment force and the first central bending moment force, respectively.

[0012] This disclosure discloses a rolling mill connected to a processor, a strip shape measuring device, and a controller. The rolling mill includes a roll set, a central pressure device, and an edge pressure device. The roll set is used to roll the steel strip passing between the two rolls. The central pressure device is connected to the roll set and applies a central bending moment force to the central portion of the two rolls in the approach direction. The edge pressure device is connected to the roll set and applies an edge bending moment force to the edge portion of the two rolls in the separation direction. The strip shape of the finished product is measured by the strip shape measuring device and calculated by the processor. The central pressure device and the edge pressure device are controlled by the controller connected to the processor, which adjusts the pressure weights of the central pressure device and the edge pressure device according to the strip shape. Simple Explanation of the Diagram

[0013] To gain a more complete understanding of the embodiments and their advantages, the following description, taken in conjunction with the accompanying drawings, is provided, wherein: Figure 1 is a schematic diagram of a rolling mill output plate shape control system according to an embodiment of this disclosure; Figure 2 is a schematic diagram of the pressure applying device to the work roll assembly according to an embodiment of this disclosure; Figure 3 is a schematic diagram of a rolling mill shape control method according to an embodiment of this disclosure; Figure 4 is a schematic diagram of the plate shape change in one embodiment of this disclosure; Figure 5 is a schematic diagram of the plate shape change in one embodiment of this disclosure; and Figure 6 is a schematic diagram of the plate shape change in one embodiment of this disclosure. Implementation

[0014] The embodiments disclosed herein are discussed in detail below. However, it will be understood that the embodiments provide many applicable concepts that can be implemented in a wide variety of specific situations. The discussed and disclosed embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0015] Furthermore, the term "connection" as used in this disclosure can refer to two or more elements being directly or indirectly connected by physical, electrical contact, or communication. The terms "first," "second," etc., as used in this disclosure, unless otherwise specified, do not specifically indicate order or sequence, but are merely used to distinguish elements or operations described using the same technical terminology.

[0016] Figure 1 is a schematic diagram of a mill output shape control system 100 according to an embodiment of this disclosure. As shown in Figure 1, the mill output shape control system 100 includes a mill 110, a shape measuring device 120, a processor 130, and a controller 140, wherein the mill 110 is connected to the shape measuring device 120 and the controller 140, and the shape measuring device 120 and the controller 140 are connected to the processor 130. The mill 110 includes a roll assembly 111, a central pressure device 112, and an edge pressure device 113, wherein the roll assembly 111 is connected to the central pressure device 112 and the edge pressure device 113.

[0017] In one embodiment, the rolling mill 110 can be multiple and form a multi-station continuous rolling mill. In this embodiment, the rolling mill 110 controlled by the processor 130 specifically refers to the final rolling mill 110 in the continuous rolling mill, but it can be adjusted according to production line requirements and equipment design. For example, multiple rolling mills 110 near the final station can be controlled simultaneously. This disclosure does not particularly limit this. The work roll group 111 consists of two oppositely arranged work rolls in the rolling mill 110. The steel strip passes between the two work rolls and contacts the two work rolls from the top and bottom to perform rolling. In actual operation, there are other rolls such as intermediate rolls and support rolls outside the work roll group 111. In this embodiment, the work roll group 111 is the main element for controlling the strip shape. In addition, each work roll has a crown that protrudes from the center in the direction of contact with the steel strip. During the rolling process, the size of the crown will affect the rolling condition of the central area of ​​the steel strip. For example, when the crown is larger, the central area of ​​the steel strip will be more elongated after rolling.

[0018] In the roller assembly 111, there are central pressure devices 112 and edge pressure devices 113 on the outer sides of the two rollers, and they are controlled by the processor 130 through the controller 140. Figure 2 is a schematic diagram of the pressure application device applying pressure to the work roll group 111 in one embodiment of the present disclosure. As shown in Figure 2, the steel strip S passes between the work rolls 111a and 111b in the work roll group 111. The central pressure application device 112 applies a central bending moment force F1 to the central part of the two work rolls from above the work roll 111a and below the work roll 111b in the approach direction of the two work rolls approaching each other, that is, towards the steel strip S. The edge pressure application device 113 applies an edge bending moment force F2 to the edge part of the two work rolls from above the work roll 111a and below the work roll 111b in the separation direction of the two work rolls separating each other, that is, towards the direction away from the steel strip S. In order to control the work roll bending moment force applied to different positions of the steel strip S in the work roll group 111 during the rolling of the steel strip S, the degree of rolling of the steel strip S at different positions is adjusted. The central pressure device 112 and the edge pressure device 113 mentioned in this disclosure apply pressure to the work roll assembly 111 and apply pressure in the corresponding direction to the work rolls 111a and 111b of the work roll assembly 111, which will not be described again below.

[0019] In one embodiment, the central pressure device 112 and the edge pressure device 113 can be further divided to correspond to different positions of the roller group 111. For example, the two central pressure devices 112 apply different central bending moment forces F1 to the central part of the roller group 111 near the center and to the position further away from the center, respectively, and the two edge pressure devices 113 apply different edge bending moment forces F2 to the edge part of the roller group 111 near the center and to the position further away from the center, respectively, so as to achieve finer control over the plate shape. Furthermore, the central pressure device 112 and the edge pressure device 113 disclosed herein are distinguished by their pressure application positions relative to the roller assembly 111, and are not limited to using multiple pressure devices. They may also include multiple pressure elements capable of applying pressure to different positions within the same pressure device, or the roller assembly 111 itself may have an adjustment function for the bending moment force of each part of the roller, or any device capable of applying corresponding central bending moment force F1 and edge bending moment force F2 to each position of the roller assembly 111 through control. This disclosure does not particularly limit these aspects.

[0020] After the steel strip is rolled by the roll group 111 of the rolling mill 110, the shape of the steel strip is measured by the shape measuring device 120, and the result is transmitted to the processor 130 for calculation and displayed on the screen of the display (not shown). In one embodiment, the shape measuring device 120 is a device installed in the rolling mill 110 to measure the shape of the steel strip at different positions. For example, an ABB Stressometer is used to measure the steel strip S by passing it through a shape detection roll, and the processor 130 quantifies the shape based on the shape unit I-Unit, describing the shape of the steel strip S as it exits the mill using the flatness F of the steel strip. The shape unit I-Unit is the ratio of the change in steel strip length ∆L in the detection area of ​​each shape detection roll to the relative reference length L, and the flatness F is expressed as... I-Unit, where a positive flatness F represents steel strip stretching and a negative flatness represents steel strip compression, and the processor 130 calculates the flatness corresponding to each part of the steel strip in the lateral position in the vertical direction of travel.

[0021] In the field of rolling, such as in the production of a four-roll cold rolling mill, common patterns after measurement by a strip shape measuring device 120 include: center wave, edge wave, and center wave with edge wave. A center wave indicates that the central area of ​​the steel strip is longer and looser than the edge area, so the flatness shows a curve with a higher central area and lower sides; an edge wave indicates that the edge area is longer and looser than the central area, so the flatness shows a curve with a higher edge area and lower central area; a center wave with edge wave indicates that the overall flatness is center wave, but the flatness at the edges shows an upward edge wave.

[0022] As shown in Figure 2, the cause of the edge wavy pattern in the medium-wave pattern is that when the steel strip S passes through the roll group 111, the contact points P1~P4 where the edge of the steel strip S contacts the roll group 111 are stress-concentrated, causing the edge of the steel strip S to generate edge wavy patterns due to pressure. In addition, even simple medium-wave or edge wavy patterns may result in under-rolling or over-rolling. Therefore, the mill output shape control system 100, based on the currently detected shape, selects roll groups 111 with different crowns and adjusts the central bending moment force F1 and edge bending moment force F2 applied to the roll group 111 by the central pressure device 112 and the edge pressure device 113 to ensure that the shape meets the production target.

[0023] Figure 3 is a schematic diagram of a mill discharge plate shape control method 300 according to an embodiment of this disclosure. The operation of the mill discharge plate shape control system 100 will be described below with reference to Figures 1 to 3.

[0024] First, step S301 is performed to determine the roll crown of the roll group 111 to be used. Specifically, since the roll crown affects the rolling degree of the central region of the steel strip, a larger crown results in greater elongation of the central region of the rolled steel strip S and increased flatness, and vice versa, the roll crown can be selected according to requirements. When insufficient rolling force is found in the central part of the steel strip S during the rolling process, resulting in excessive compression, or when side waves occur in the middle wave zone, increasing the roll crown helps to elongate the central region of the steel strip S and suppress side waves. In one embodiment, the appropriate roll crown can be selected in advance or when an undesirable strip shape is found, indicated by the processor 130, for example, increasing the roll crown by 50-150% when undesirable side waves occur.

[0025] After determining the roll crown of the roll set 111 to be used, step S302 is performed, in which the steel strip S is rolled using the roll set 111. Then, step S303 is performed, in which the shape measurement device 120 measures and generates the shape measurement data of the steel strip S after rolling, and then transmits it to the processor 130 to calculate the shape based on the shape measurement data. After obtaining the shape, step S304 is performed, in which the processor 130 determines whether the steel strip S has an undesirable shape based on the shape. If so, step S305 is performed, in which the processor 130 adjusts the pressure weight of the shape adjustment based on the current shape of the steel strip S to instruct the controller 140 to control the pressure device. Otherwise, step S302 is returned to continue rolling. In step S304, determining whether an undesirable strip shape has occurred can be achieved by pre-setting a flatness target. When the measured flatness of the strip shape differs significantly from the target value, automatic adjustment is performed. After adjustment, the process returns to steps S303 and S304 to continuously measure the strip shape of the output steel strip S and determine whether an undesirable strip shape still occurs. If so, adjustment is performed again in step S305 until the output steel strip S no longer produces an undesirable strip shape. Furthermore, if the strip shape continues to exhibit an undesirable shape despite multiple adjustments in step S305, the adjustment of the pressure device can be switched to manual operation. Additionally, a new mill 110 can be added to control the strip shape of the mill 110 preceding the one automatically controlled in the continuous rolling mill, combining the adjustments of both mills to achieve the target strip shape control. For multi-station mill control, the processor 130 can also connect to a controller 140 that controls multiple mills 110.

[0026] In step S305, the pressure weight is used to control the central bending moment force F1 and the edge bending moment force F2 applied to the roll group 111 by the central pressure device 112 and the edge pressure device 113. Specifically, the roll group 111 has a preset pressure applied to the steel strip S during rolling, and the pressure weight can be adjusted based on the original applied pressure. When the pressure weight corresponding to the central bending moment force F1 increases, the bending force of the rolls in the central area of ​​the steel strip S is strengthened, and if it is reduced, the bending force of the rolls is weakened. When the pressure weight corresponding to the edge bending moment force F2 increases, the bending force of the rolls in the edge area of ​​the steel strip S is weakened, and if it is reduced, the bending force of the rolls is increased, thereby adjusting the influence of each area of ​​the roll group 111 on the strip shape. Figures 4 to 6 are schematic diagrams of plate shape changes in one embodiment of this disclosure, wherein curve C reflects the trend of plate shape. The plate shape changes under the control of the central pressure device 112 and the edge pressure device 113 by adjusting the pressure weight when different undesired plate shapes occur are described below with reference to Figures 4 to 6.

[0027] Figure 4(a) shows the undesired waveform of the steel strip with mid-wave edge ripples. As can be seen from the figure, although the flatness graph roughly presents a mid-wave curve, the flatness at corresponding positions on both sides of the steel strip increases, indicating stress concentration at the steel strip edges, resulting in undesired edge ripples. In response to these undesired edge ripples, the processor 130 can instruct the replacement with a roll group 111 with a larger crown or increase the pressure weight of the edge pressure device 113, for example, adjusting it to 300-600% of the original, to increase the edge bending moment F2 and avoid the generation of undesired edge ripples. In one embodiment, the flatness can also be more precisely controlled by increasing the pressure weight of another edge pressure device 113 closer to the center than the aforementioned edge pressure device 113, for example, adjusting it to 10-100% of the original, where the pressure weight of the edge pressure device 113 closer to the edge is greater than that of the edge pressure device 113 closer to the center. The adjusted plate shape is shown in Figure 4(b), and no slope is generated at the edge of the steel strip.

[0028] Figure 5(a) shows an excessively large central wave in the steel strip due to over-rolling in the central region, exceeding the target strip shape. To address this excessive central wave, the processor 130 can reduce the pressure weight of the central pressure device 112, for example, by adjusting it to -10% to -100% of its original value, to control the central pressure device 112 and reduce the central bending moment force F1. It can also increase the pressure weight of the edge pressure device 113, for example, by adjusting it to 300% to 600% of its original value, to increase the edge bending moment force F2. The adjusted strip shape is shown in Figure 5(b). The difference H1 between the highest and lowest flatness of the original central wave is reduced to H2 after adjustment, indicating that this adjustment helps suppress the generation of excessive central waves.

[0029] The target of Figure 6 is to generate a plate shape with micro-edge ripples. In Figure 6(a), the plate shape without adjustment is an undesirable excessively large medium wave. To adjust this medium wave plate shape to a micro-edge ripple plate shape, the processor 130 can reduce the pressure weight of the central pressure device 112, for example, by adjusting it to -100 to -500% of the original value, so as to control the central pressure device 112 to reduce the central bending moment force F1. In one embodiment, the plate shape can also be more precisely controlled by increasing the pressure weight of another central pressure device 112 that is farther from the center than the aforementioned central pressure device 112 in the central part of the roller group 111, for example, by adjusting it to -100 to -500% of the original value. The pressure weight is that the central pressure device 112 near the center is smaller than the central pressure device 112 near the edge. The adjusted plate shape is shown in Figure 6(b). Originally, it was a medium-wave plate shape with a stretched central region and a relatively tight edge region. After adjustment, it can be obtained as a micro-edge wave plate shape with a compressed central region and a stretched edge region.

[0030] The rolling mill output shape control system and rolling mill disclosed herein, through the selection of appropriate roll crown and the setting of shape targets for automated control, can reduce the workload of personnel, reduce strip shape defects, and improve the detection rate of rolled-in black core foreign objects through shape adjustment. Furthermore, the rolling mill output shape control system and rolling mill disclosed herein can be applied to various high-grade steel products requiring precise shape control, improve the coil quality and output shape stability of tandem cold rolling mills, effectively increase tandem process productivity, and reduce manpower and material consumption.

[0031] Although this disclosure has been disclosed above with reference to embodiments, it is not intended to limit this disclosure. Anyone skilled in the art may make some modifications and refinements without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims.

[0032] 100: Rolling Mill Output Plate Shape Control System 110: Rolling Mill 111: Worker Roller Group 111a, 111b: Worker rollers 112: Central pressure application device 113: Edge pressure device 120: Plate Shape Measuring Device 130: Processor 140: Controller 300: Rolling Mill Exit Plate Shape Control Method C: Curve F1: Central bending moment F2: Edge bending moment force P1~P4: Contact points S: Steel strip S301~S305: Steps H1, H2: Difference

Claims

1. A strip shape control system for a rolling mill, comprising: a rolling mill, including: a first roll group for rolling a strip of steel passing between two rolls of the first roll group; a first central pressure device connected to the first roll group, the first central pressure device being used to apply a first central bending moment force to a central portion of one of the two rolls in an approach direction in which the two rolls approach each other; and a first edge pressure device connected to the first roll group, the first edge pressure device being used to apply a first edge bending moment force to an edge portion of one of the two rolls in a separation direction in which the two rolls separate from each other; and a controller connected to the rolling mill, the controller being used to control the first central pressure device and the first edge pressure device; A strip shape measuring device is connected to the rolling mill. The strip shape measuring device is used to measure and generate strip shape measurement data of the strip after rolling. A processor is connected to the rolling mill, the controller and the strip shape measuring device. The processor is used to calculate a strip shape based on the strip shape measurement data and adjust the pressure weight of the first central pressure device and the first edge pressure device accordingly. The processor instructs the controller to control the first central pressure device and the first edge pressure device according to the pressure weight.

2. The mill output sheet shape control system as described in claim 1, wherein the processor is further configured to instruct the first roll group to be replaced with a second roll group whose roll crown is greater than that of the first roll group when an undesirable slope occurs in the sheet shape.

3. The mill output plate shape control system as described in claim 1, wherein the processor is further configured to increase the pressure weight of the first edge pressure device when the plate shape exhibits an undesirable slope, thereby instructing the controller to control the first edge pressure device to increase the first edge bending moment force.

4. The mill output plate shape control system as described in claim 1, wherein the processor is further configured to reduce the pressure weight of the first central pressure device when an excessively large mid-wave occurs in the plate shape, thereby instructing the controller to control the first central pressure device to reduce the first central bending moment force.

5. The mill output sheet shape control system as described in claim 1, wherein the processor is further configured to increase the pressure weight of the first edge pressure device when an excessively large mid-wave appears in the sheet shape, so as to instruct the controller to control the first edge pressure device to increase the first edge bending moment force.

6. The mill output sheet shape control system as claimed in claim 1, wherein the mill further comprises: a second central pressure device connected to the first work roll group, the second central pressure device being used to apply a second central bending moment force, farther from the central portion than the first central pressure device, to the central portion of the two work rolls in the approach direction; and a second edge pressure device connected to the first work roll group, the second edge pressure device being used to apply a second edge bending moment force, closer to the central portion than the first edge pressure device, to the edge portion of the two work rolls in the separation direction; wherein, The processor is further used to determine the pressure weight of the second central pressure device and the second edge pressure device according to the plate shape, and to instruct the controller to control the second central pressure device and the second edge pressure device according to the pressure weight.

7. The mill output plate shape control system as described in claim 6, wherein the processor is further configured to increase the pressure weight of the first edge pressure device and the second edge pressure device respectively when the plate shape has an undesirable slope, so as to instruct the controller to control the first edge pressure device to increase the first edge bending moment force and control the second edge pressure device to increase the second edge bending moment force, wherein the pressure weight is greater for the first edge pressure device than for the second edge pressure device.

8. The mill output sheet shape control system as described in claim 6, wherein the processor is further configured to reduce the pressure weight of the first central pressure device and the second central pressure device respectively when the sheet shape exhibits an excessively large mid-wave, so as to instruct the controller to control the first central pressure device to reduce the first central bending moment force and control the second central pressure device to reduce the second central bending moment force, wherein the pressure weight is that the first central pressure device is less than the second central pressure device.

9. The mill output plate shape control system as described in claim 1, wherein the pressure weight is an adjustment factor of one of the first edge bending moment force and the first central bending moment force, respectively.

10. A rolling mill connected to a processor, a strip shape measuring device, and a controller, the rolling mill comprising: a roll set for rolling a strip through the space between two rolls of the roll set; a central pressure device connected to the roll set, the central pressure device applying a central bending moment force to a central portion of one of the two rolls in an approach direction in which the two rolls approach each other; an edge pressure device connected to the roll set, the edge pressure device applying an edge bending moment force to an edge portion of one of the two rolls in a separation direction in which the two rolls separate from each other; and wherein the strip shape exiting after rolling is measured by the strip shape measuring device and calculated by the processor, and the central pressure device and the edge pressure device are controlled by the controller connected to the processor according to a pressure weight indication corresponding to the central pressure device and the edge pressure device adjusted by the processor based on the strip shape.

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