Method and computer program product for operating a casting and rolling system

Abstract

The present invention relates to a method and computer program product for operating a casting and rolling system, as well as the corresponding casting and rolling system itself. The casting and rolling system 100 comprises a casting facility 110 and a rolling facility 120 arranged downstream in a casting direction G. The casting facility 110 and the rolling facility 120 are connected to each other via a continuous cast strand 20 in a continuous operating mode. To guide the cast strand 20 through the casting and rolling system, multiple driver roll pairs are present within the casting facility 110 or at least in front of the first rolling stand 122. To at least reduce, and preferably avoid, unwanted disruptions to the casting process and / or driver roll slippage, the present invention proposes that only one of these driver roll pairs 118 functions as a master driver roll pair to control the casting speed of the cast strand 20. In addition to the master driver roll pair 118, at least one slave driver roll pair 116 is provided within the casting facility 110 or in front of the first rolling stand 122, which must follow the master driver roll pair 118 in terms of casting speed. According to the present invention, the slave driver roll pair 116 is rotationally torque controlled.

Description

[Technical Field]

[0001] The present invention relates to a method and a computer program product for operating a casting and rolling system having a casting facility and a rolling facility arranged downstream of the casting facility in the casting direction, the casting facility 110 and the rolling facility 120 being connected to each other via a continuous cast strand 20 in a continuous operating mode. Furthermore, the present invention relates to a corresponding casting and rolling system. [Background technology]

[0002] Such combined casting and rolling systems and methods for operating them are basically known in the prior art. Japanese Patent Application Publication No. 2010-253450 discloses a method for controlling the speed of the first rolling stand at the rear of a casting facility. For this purpose, the speed control is adjusted by an additional control device until the control deviation falls within a preset range. All drivers in the casting facility are individually speed-controlled, and all drivers are preset to the same target value. This method maintains the speed of the first rolling stand within a predetermined range, but does not take into account the rotational torque of the drivers in the casting machine. Because all drivers in the casting facility are speed-controlled and operate according to the same target value, slippage of the driver rolls may occur.

[0003] The same applies to Japanese Patent Application No. 58-218304. This patent application discloses speed control in a combined casting and rolling apparatus. In this case, a first driver in front of a first rolling stand is used as a control element for controlling the actual casting speed to a preset target casting speed. The casting belt and other drivers in the casting equipment are similarly operated in a speed-controlled manner and have the actual speed of the first driver as a target value. The rolling stands connected downstream of the casting equipment are similarly speed-controlled. In this case, the speed target value is adjusted so that the rotation torque of the first driver is maintained constant. According to the disclosure of this patent application, although the driver rotation torque is indeed used to control the first rolling stand, all other drives are speed-controlled by presetting the same target value. This may result in slippage of the driver rolls.

[0004] Similarly, WO 2021140531 and EP 3000539 each disclose a method for operating a casting and rolling system during continuous operation. This method proposes using the first rolling stand at the rear of the caster as a "speed master" to control the desired target speed. However, due to changing boundary conditions during the casting process, the thickness regularly fluctuates along the length of the cast strand, resulting in undesirable fluctuations in mass flow. If the first rolling stand is rolled at a casting speed controlled to a constant target value and the final thickness is very precisely controlled, the casting speed of the upstream casting equipment must be frequently adjusted. This is cumbersome for the casting process. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2010-253450 [Patent Document 2] Showa 58-218304 [Patent Document 3] International Publication No. 2021140531 [Patent Document 4] European Patent No. 3000539 Summary of the Invention [Problem to be solved by the invention]

[0006] It is therefore an object of the present invention to improve known methods and computer program products for operating a combined casting and rolling system, as well as corresponding known casting and rolling systems, in such a way that the above-mentioned undesired disturbances of the casting process and / or slippage of the driver rolls are reduced and preferably avoided. [Means for solving the problem]

[0007] This problem is solved by a method according to claim 1, characterized in that the driver roll pair is a master driver roll pair that functions as a single control element for controlling the casting speed of the cast strand within the strand guide device or at the outlet of the strand guide device in front of the first rolling stand, and at least one slave driver roll pair is provided adjacent to the master driver roll pair upstream of the first rolling stand, particularly within the strand guide device, and the actual rotational torque of the rolls of the slave driver roll pair is controlled to a preset target rotational torque.

[0008] The target casting speed is preset by the operator of the casting and rolling system or by an associated production planning device before and during the casting and rolling process.

[0009] The terms "upstream of the first rolling stand" or "forward of the first rolling stand" include all locations or positions in the casting and rolling system forward of the first rolling stand where a cast strand is already present, i.e., it includes the area of the strand guide device, includes the area between the exit of the strand guide device and the first rolling stand, and means the area between the exit of the mold and the first rolling stand, excluding the first rolling stand.

[0010] The driver or driver device is a drive roll pair having a pressure section for transmitting rotational torque to the cast strand passing through the driver. If the driver device is located within a strand guide device, the rolls are strand guide rolls. Instead of or in addition to the strand guide roll pair, any other drive roll pair may function as a slave driver device in front of the first rolling stand. If the driver device is located in a rolling system, the rolls are, for example, work rolls of the rolling stand. Instead of or in addition to the work roll pair, any other drive roll pair may function as a slave driver device in the rolling facility. Typically, an electric motor serves as the rotation drive for the rolls.

[0011] Continuous operation of a casting and rolling system is characterized in that all system components, from the casting facility through the rolling mill and the subsequent winding area of the rolling mill, are connected to one another by the cast strand or rolled metal band. In this case, only one driver roll pair in front of the first rolling stand can be the "Speed Master" and preset the casting speed, while all other drivers in the casting and / or rolling facilities are slave drivers that must follow or adjust to the casting speed preset by the "Speed Master" as described in the present invention. In particular, this means that the slave driver roll pairs cannot be operated with casting speed control in either the casting facility or the rolling facility.

[0012] The master driver roll pair of the present invention in the casting installation, or at least in front of the first rolling stand, ensures that the casting device operates as consistently as possible. Disturbances in the casting process that occur during actual operation, such as cast strand thickness variations, measurement errors or roll wear, can be at least largely or completely eliminated by the arrangement of the "SpeedMaster" in the casting direction in front of the first rolling stand.

[0013] Furthermore, the above object of the present invention is solved by a computer program product according to claim 12 and a casting and rolling system according to claim 13. The advantages of these solutions correspond to the advantages explained for the above method.

[0014] Preferred configurations of the above method and of the above casting and rolling system are set out in the dependent claims.

[0015] Two figures are attached to the specification. [Brief explanation of the drawings]

[0016] [Figure 1] A rolling mill having a casting speed control device according to the first embodiment of the present invention [Figure 2] A rolling mill having a casting speed control device according to a second embodiment of the present invention DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in detail below with reference to the above figures of embodiments, in which the same technical components are designated by the same reference numerals.

[0018] FIG. 1 shows a casting and rolling system 100 of the present invention. The casting and rolling system 100 includes a casting facility 110. The casting facility 110 itself is composed of a mold 112 for casting a cast strand 20 and a strand guide device 114, which is disposed behind the mold in the casting direction G and has strand guide rolls for transporting the cast strand 20. In both the curved deflection region of the strand guide device 114 and the horizontal discharge region of the strand guide device 114, two opposing strand guide rolls can form a driver roll pair. According to the present invention, exactly one roll pair or one roll pair of the plurality of roll pairs is provided as a master driver roll pair 118 at the exit of the strand guide device 114 in front of the first rolling stand 122 as a control element for controlling the casting speed of the cast strand 20 by a casting speed control device 142. The casting speed controller 142 is configured to control the actual casting speed to a preset target casting speed by appropriately varying the power or current driving the master driver roll pair 118. Therefore, the casting speed controller 142 is a "speed master" or main controller within the meaning of the present invention.

[0019] For rolling the cast strand 20, a rolling installation 120 having at least one first rolling stand 122 is arranged behind the casting installation 110 in the casting direction G. In this case, in particular, the casting installation 110 and the rolling installation 120 are operated in a continuous operating mode, in which they are connected to each other via the continuous cast strand 20.

[0020] In addition to the master driver roll pair 118, the casting equipment 110, particularly the strand guide device 114 of the casting equipment 110, is provided with at least one slave driver roll pair 116 that is controlled to a predetermined target rotational torque by a rotational torque control device 144.

[0021] Basically, the casting and rolling system 100 is configured to carry out the method of the present invention, which is described below: In the continuous operation mode, the cast strand 20 cast in the mold is guided by the strand guide rolls of the strand guide device 114 and transported by the casting and rolling system 100 in the casting direction. Using the casting speed control device 142, the actual casting speed of the cast strand 20 is controlled to a preset target casting speed by appropriately changing the power or current driving the master driver roll pair 118.

[0022] 1 shows a first embodiment for controlling the casting speed according to the present invention. In this embodiment, the rotational speed at which the master driver roll pair 118 is driven is specified as a control variable, and a target casting speed is preset as the target rotational speed at which the master driver roll pair 118 is driven. In this control, the casting speed represented by the actual rotational speed at which the master driver roll pair 118 is driven is controlled to the target casting speed represented by the preset target rotational speed at which the master driver roll pair 118 is driven.

[0023] 2 shows another configuration for controlling the casting speed in accordance with the present invention. In this second embodiment, the casting speed of the cast strand 20 or the speed of the surface of the cast strand 20 is defined as the controlled variable. That is, the actual casting speed, represented by the actual casting speed of the cast strand 20 or the actual casting speed of the surface of the cast strand 20, is controlled to a preset target casting speed, represented by a preset target casting speed for the cast strand or the surface of the cast strand. In this case, the master driver roll pair 118 functions as the control element.

[0024] The following applies equally to both embodiments of controlling the casting speed according to the present invention: In addition to the master driver roll pair 118, the casting facility 110 is provided with at least one roll pair 116 as a so-called slave driver roll pair. Only the master driver roll pair 118 is speed-controlled according to the method of the present invention. In contrast, the at least one slave driver roll pair 116 is torque-controlled by a slave torque control device 144. That is, the actual torque of the rolls of the slave driver roll pair 116 is controlled to a preset target torque.

[0025] When multiple slave driver roll pairs 116 are present in the casting facility 110 or in the casting direction ahead of the first rolling stand 122, all of these slave driver roll pairs 116 are individually torque controlled as described above. In this case, the target torques for these slave driver roll pairs 116 preferably correspond to a predetermined distribution of drive torques for these slave driver roll pairs 116.

[0026] The casting and rolling system 100 can be operated not only in the continuous operation mode in which the cast strand 20 is transported into at least the first rolling stand 122 and rolled by this rolling stand 122, but also in a start-up mode prior to the continuous operation mode. In this start-up mode, the cast strand 20 is cast in the casting facility 110 and transported to the front of the first rolling stand 122 of the rolling facility. In both operation modes, the casting speed can be controlled according to both of the above-described embodiments described with reference to Figures 1 and 2. In this case, the target casting speed for the master driver roll pair 118 is preferably preset to the same value and constant over time in both the start-up mode and the continuous operation mode.

[0027] At least one slave driver roll pair may be provided not only in the casting facility 110 but also in the rolling facility 120. In a rolling facility, such a slave driver roll pair is generally formed by the work rolls 124 of a rolling stand 122, and in particular by the work rolls of the first rolling stand 122 arranged in the casting direction G. For this slave driver roll pair in a rolling facility, the slave driver roll pair does not have to be controlled to the casting speed according to the method of the present invention. Rather, the slave driver roll pair is torque-controlled during a continuous operation mode. That is, the actual torque of the rolls of the slave driver roll pair 124 in the rolling stand is controlled to a predetermined target torque.

[0028] Preferably, the rotational torque of each of the rolls of the slave driver roll pair 116 in the strand guide device 114 and / or the rolls of the slave driver roll pair 124 in the rolling installation 120 is controlled by appropriately varying the current during the drive of the roll, where the current is varied as a control variable for the drive so that the actual rotational torque is adapted to or controlled to a desired or preset target rotational torque.

[0029] Alternatively, the rotational torque of the rolls of the slave driver roll pairs in the strand guide device 114 and / or the rolling mill 120 may be controlled by appropriately changing the rotational speed of the rolls as a controlled variable. That is, each respective rotational torque controller 144, 146 presets an appropriate change in rotational speed as a controlled variable for rotating the respective slave driver roll pair, and the driving current is then appropriately adjusted to effect the required change in rotational speed. According to another embodiment, the changed rotational speed as a controlled variable can be maintained at the preset rotational speed during the change by using a subordinate rotational speed controller 148 in at least one of the rotational torque controllers 144, 146.

[0030] The changed rotational speed as a control variable, and the optional lower rotational speed control during upper rotational torque control, advantageously ensure that the cast strand 20 between the casting facility 110 and the first rolling stand 122 does not expand. The application of excessively high tension to the cast strand 20 between the casting facility 110 and the first rolling stand 122 and idle driving of one of the drives of the slave driver roll pairs 166, 124 are advantageously avoided. If the drive rotational torque of the slave driver roll pair 116 in the casting facility 110 increases, the first rolling stand 122 must rotate faster; i.e., a higher rotational speed is preset as a control variable. Conversely, if the drive rotational torque of the driver roll pair 116 in the casting facility 110 decreases, the first rolling stand 122 must rotate correspondingly slower; i.e., a lower rotational speed is preset as a control variable.

[0031] For example, the target rotational torque for the work rolls 124 of the preferred first rolling stand 122 of the rolling facility 120 may be preset as the actual rotational torque of one slave driver roll pair 116 of the multiple slave driver roll pairs 116 in the strand guide device 114. Alternatively, the target rotational torque for the work rolls 124 may be preset as the total rotational torque of at least two, and preferably all, of the slave driver roll pairs 116 in the strand guide device 114.

[0032] During the start-up mode, before the cast strand is transported into the first rolling stand 122, the rotational torques of at least two, and preferably all, driver roll pairs 116 are measured and stored in front of the first rolling stand 122 and added to the total rotational torque to calculate the total rotational torque. [Explanation of symbols]

[0033] 100 Casting and Rolling System 110 Casting Equipment 112 Mold 114 Strand guide device 116 Slave driver roll pair in front of first rolling stand 118 Master driver roll pair in front of first rolling stand 120 Rolling Equipment 122 Rolling Stand 124 Slave driver roll pair of work roll configuration of rolling stand 142 Casting speed control device for master driver roll pair 144 Slave Torque Control Device for Casting Equipment 146 Slave Torque Controller for Rolling Mill 148 Lower speed control device 20 Casting Strands G Casting direction

Claims

1. A method for operating a casting and rolling system (100) comprising: a casting facility (110) having a mold (112) for casting a continuous cast strand (20) and a strand guide device (114) arranged downstream of the mold (112) in a casting direction (G) for guiding the cast strand (20); and a rolling facility (120) having at least one rolling stand (122) arranged downstream of the casting facility (110) in the casting direction (G) for rolling the cast strand (20), comprising: The casting facility (110) and the rolling facility (120) are operated in a continuous operation mode in which the casting facility (110) and the rolling facility (120) are connected to each other via the continuous casting strand (20), and the following occurs: controlling the actual casting speed of the cast strand (20) to a preset target casting speed by appropriately varying the power driving a driver roll pair (118) within a strand guide device (114) of the casting facility (110) or at an exit of the casting facility (110) ahead of the first rolling stand (122) of the rolling facility (120); The cast strand (20) is guided between the rolls of the driver roll pair (118) and conveyed by these rolls through the casting and rolling system (100) in a casting direction (G), the driver roll pair (118) is a master driver roll pair that functions as a single control element for controlling the casting speed of the cast strand (20); Upstream of the first rolling stand (122), at least one slave driver roll pair (116) is located adjacent to the master driver roll pair (118); The method is characterized in that the actual rotational torque of the rolls of the slave driver roll pair (116) is controlled to a preset target rotational torque.

2. 2. The method of claim 1, wherein the casting and rolling system (100) is operated in a start-up mode in which the cast strand (20) is cast in the casting facility (110) and transported in front of the first rolling stand (122) of the rolling facility (120) prior to a continuous operation mode in which the cast strand (20) is transported to at least a first rolling stand (120) of the rolling facility (120) and rolled by the rolling stand (122).

3. 3. The method of claim 2, wherein a target casting speed for the master driver roll pair (18) is preset to the same value and constant in time in the mode and the operating mode.

4. When controlling the casting speed, the number of rotations for driving the master driver roll pair (118) is specified as a control variable, and the target casting speed is preset as the target number of rotations for driving the master driver roll pair (118); or 4. The method according to claim 1, wherein, during the control of the casting speed, the speed of the cast strand or the speed of the surface of the cast strand (20) is specified as a control variable, and the target casting speed is preset as a target casting speed of the cast strand or a target casting speed of the surface of the cast strand for driving the master driver roll pair (118).

5. 5. The method of claim 1, wherein when multiple slave driver roll pairs (116) are present in the casting facility (110), target rotational torques for these slave driver roll pairs (116) are preset according to a desired distribution of drive torques.

6. The rolling equipment (120) is provided with at least one slave driver roll pair as a work roll (124) in one rolling stand (122) of a plurality of rolling stands (122) of the rolling equipment (120), in particular in the first rolling stand (122) in the casting direction (G), 6. The method according to claim 1, wherein - during a continuous operation mode - the actual rotational torque of the rolls of the slave driver roll pair (124) in the rolling installation (120) is controlled to a preset target rotational torque.

7. 7. The method of claim 6, wherein the rotational torque of the rolls of the slave driver roll pair (116) in front of the first rolling stand (122) and / or the rolls of the slave driver roll pair (124) in the rolling installation (120) is controlled by appropriately changing the current as a control variable during the driving of the rolls.

8. 7. The method of claim 6, wherein the rotational torque of the rolls of the slave driver roll pair in front of the first rolling stand (122) and / or the rolls of the slave driver roll pair in the rolling installation (120) is controlled by appropriately changing the rotational speed as a control variable of the rolls of the slave driver roll pair (124).

9. 9. The method according to claim 8, wherein the rotational speed changed as a control variable is maintained at a preset rotational speed during the change to the rotational torque control by using a subordinate rotational speed control device (148) in at least one of the rotational torque control devices (144, 146).

10. 10. The method according to claim 6, wherein the target rotational torque for the work rolls (124) of the preferred first rolling stand (122) of the rolling installation (120) is preset as the rotational torque of one slave driver roll pair (116) in front of the first rolling stand (122), in particular in the strand guide device (114), or as the total rotational torque of at least two, preferably all, slave driver roll pairs (116) in front of the first rolling stand (122).

11. 11. The method according to claim 10, characterized in that during a start-up mode, before the cast strand (20) reaches the first rolling stand (122), the rotational torques of at least two, preferably all, driver roll pairs (116) are measured and stored in front of the first rolling stand (122) and added to the total rotational torque, thereby calculating the total rotational torque.

12. A computer program product loadable into the internal memory of a digital computer, the computer program product having software code portions, 12. A computer program product, wherein the software code portions perform the steps according to the method of any one of claims 1 to 11 when the computer program product is run on the computer.

13. a casting facility (110) including a mold (112) for casting a continuous cast strand (20) and a strand guide device (114) for guiding the cast strand (20) and having strand guide rolls arranged downstream of the mold (112) in a casting direction (G); a rolling facility (120) for rolling the cast strand (20) and having at least one rolling stand (122) arranged downstream of the casting facility (110) in the casting direction (G); a casting speed control device (142) for controlling the actual casting speed of the cast strand (20) to a preset target casting speed by appropriately changing the power driving a driver roll pair using a driver roll pair in a strand guide device (114) of the casting equipment (110) or a driver roll pair located at the outlet of the casting equipment (110) along the casting direction (G) ahead of a first rolling stand (122) of the rolling equipment (120); A casting and rolling system (100) comprising: In the casting and rolling system, the casting equipment (110) and the rolling equipment (120) are operable in a continuous operation mode while being coupled to each other via the continuous casting strand (20), the driver roll pair is a master driver roll pair (118), and the casting speed control device is a master control device (142); - in the casting direction (G) - in front of the first rolling stand (122) and adjacent to the single master driver roll pair (118), at least one slave driver roll pair (116), a rolling stand (122) provided in said casting facility (110) for controlling an actual rolling torque of the rolls of at least one slave driver roll pair (116) in front of said first rolling stand (122) to a predetermined target rolling torque;

14. 14. The casting and rolling system according to claim 13, wherein at least one additional slave driver roll pair is present in the rolling facility as a work roll in one of a plurality of rolling stands.

15. The casting and rolling system (100) according to claim 13 or 14, wherein the casting and rolling system (100) is configured to carry out the method according to any one of claims 1 to 11.

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