Method and computer program product for operating a rolling system

Abstract

The invention relates to a method and a computer program product for operating a casting and rolling system (100) and to a corresponding casting and rolling system itself. The casting and rolling device (100) consists of a casting device (110) and a rolling device (120) arranged downstream in the casting direction (G). The casting plant and the rolling plant are coupled to each other in a continuous operating mode by means of a continuously cast strand (20). In the casting plant (110) or at least in front of the first roll stand (122), there is a pair of drive rollers for conveying the strand through the casting plant. In order to at least reduce and advantageously prevent undesired interference with the casting process and / or slip of the drive rollers, the invention provides that only one of the drive roller pairs (118) acts as a main drive roller pair for controlling the casting speed of the strand (20). In addition to the master drive roller pair (118), at least one slave drive roller pair (116) is provided in the casting plant (110) or in front of the first roll stand (122), which has to follow the master drive roller pair (118) in terms of casting speed. According to the invention, the driven roller pair (116) is torque-controlled.

Description

Technical Field

[0001] The invention relates to a method and a computer program product for operating a casting and rolling plant, the casting and rolling plant having a casting plant and a rolling plant arranged downstream of the casting plant in the casting direction. The casting plant and the rolling plant are coupled to each other in a continuous operating mode via the cast, continuous continuous casting strands. The invention also relates to a corresponding casting and rolling plant. Background Art

[0002] Such coupled casting and rolling equipment and operating methods thereof are basically known in the prior art. For example, Japanese patent application JP 2010253450 A discloses a method for regulating the speed of a first rolling mill stand located after a casting equipment. For this purpose, an additional control unit is used to adjust the speed control system until the control deviation is within a specified range. All drives in the casting equipment are regulated in terms of speed and are assigned the same target value. This method keeps the speed of the first rolling mill stand within a limited range, but does not take into account the torque of the drive in the casting machine. Since the drives in the casting equipment are all regulated in terms of speed and run at the same target value as described above, slippage of the drive rollers may occur here.

[0003] Similar arguments also apply to Japanese patent application JPS 58218304 A. This patent application describes a speed control system in a coupled casting and rolling plant. Here, the first drive located before the first rolling mill stand is used as an adjustment mechanism of the speed control system for regulating the actual casting speed to a specified target casting speed. The casting ring (Gieβring) and other drives in the casting device are also operated in a speed-controlled manner, and the current speed of the first drive is used as the target value. The rolling mill stand connected downstream of the casting device is also speed-controlled, wherein the speed target value is adjusted so that the torque of the first drive remains constant. According to the disclosure of the patent application, although the drive torque is used to control the first rolling mill stand, all other drives are speed-controlled in a manner that specifies the same target value. As a result, slippage of the drive roller may also occur in this case.

[0004] International patent application WO 2021 / 140531 and European patent application EP 3 000 539A each disclose a method for operating a continuously operating casting and rolling equipment. The method provides that the first rolling mill stand located after the casting machine is used as a "speed master" and is regulated to the desired target casting speed. However, due to the constantly changing boundary conditions during the casting process, thickness fluctuations often occur along the length of the continuous casting billet, and thus undesirable mass flow fluctuations occur. If rolling is carried out in the first rolling mill stand at a casting speed regulated to a constant target value and the outlet thickness is regulated very accurately, the casting speed of the upstream casting equipment must usually be adjusted accordingly. This interferes with the casting process. Summary of the invention

[0005] The object of the present invention is therefore to improve the known method and computer program product for operating a coupled casting and rolling plant and the corresponding known coupled casting and rolling plant in such a way that the described undesired interferences with the casting process and / or slippage of the drive rolls are reduced and preferably prevented.

[0006] This object is achieved by the method claimed in claim 1. The method is characterized in that the driving roller pair is a main driving roller pair, which serves as the only regulating mechanism for regulating the casting speed of the continuous casting strand in the continuous casting strand guiding device or at its outlet before the first rolling mill stand; upstream of the first rolling mill stand, in particular in the continuous casting strand guiding device, at least one slave driving roller pair is provided in addition to the main driving roller pair; and the actual torque of the rollers of the slave driving roller pair is regulated to a set target torque.

[0007] The target casting speed is set by the operator of the casting and rolling installation or by a responsible production planning device before and during the casting and rolling process.

[0008] The term "upstream of the first rolling stand" or "before the first rolling stand" includes all locations or positions in the casting and rolling plant that are located before the first rolling stand with respect to the casting direction and at which the continuous cast strand is already present. In other words, this refers to the area between the outlet of the crystallizer and the first rolling stand, including the area of ​​the continuous cast strand guide, and including the area between the outlet of the continuous cast strand guide and the first rolling stand, but excluding the first rolling stand.

[0009] The drive or drive device is a driven roller pair with power regulation for transmitting torque to the strand guided through the drive. If the drive device is arranged in the strand guiding device, the rollers are strand guiding rollers. As an alternative or in addition to the strand guiding roller pair, any other driven roller pair can also serve as a slave drive device before the first rolling mill stand. If the drive device is arranged in the rolling mill, the rollers are, for example, working rollers of the rolling mill stand. As an alternative or in addition to the working roller pair, any other driven roller pair can also serve as a slave drive device in the rolling mill. Usually, an electric motor serves as a rotation drive for the rollers.

[0010] The continuous operation of the casting and rolling plant is characterized in that all plant parts, from the casting plant to the rolling plant to the winding area arranged downstream of the rolling plant for coiling the rolled metal strip, are coupled to each other via the continuous cast strand or the rolled metal strip. In this coupled operation, only the drive roller pair before the first rolling mill stand can act as a "speed master" and set the casting speed, while all other drives in the casting plant and / or rolling plant are slave drives, which must follow the casting speed set by the "speed master" or adjust their speed accordingly, as claimed in the present invention. This means in particular that no slave drive roller pair, whether in the casting plant or in the rolling plant, may be operated in a casting speed-controlled manner.

[0011] By arranging the main drive roller pair in the casting plant or at least before the first rolling stand according to the claimed invention, it is ensured that the casting plant runs as smoothly as possible. By arranging the claimed "speed master" before the first rolling stand in the casting direction, it is possible to at least largely reduce or even eliminate disturbances to the casting process that occur in actual operation, for example disturbances caused by thickness fluctuations of the continuous cast strand, measurement errors or roller wear.

[0012] The above mentioned object of the invention is also achieved by a computer program product according to claim 12 and a casting and rolling plant according to claim 13. The advantages of these solutions correspond to the advantages mentioned above with reference to the claimed method.

[0013] Advantageous embodiments of the claimed method and of the claimed casting-rolling plant are the subject matter of the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The specification is accompanied by two drawings, among which:

[0015] Figure 1 shows a rolling plant according to the invention with a casting speed regulator according to a first embodiment; and

[0016] Figure 2A rolling mill according to the invention with a casting speed controller is shown according to a second embodiment. DETAILED DESCRIPTION

[0017] The present invention is described in detail in the form of an embodiment with reference to the accompanying drawings. In the two drawings, the same technical components are represented by the same reference numerals.

[0018] Figure 1 The casting and rolling equipment 100 according to the present invention is shown. The casting and rolling equipment includes a casting device 110, which in turn is composed of a crystallizer 112 for casting a continuous casting strand 20 and a continuous casting strand guide device 114 arranged downstream of the crystallizer along the casting direction G and having continuous casting strand guide rollers, the continuous casting strand guide rollers being used to guide the continuous casting strand 20. In the curved bending area of ​​the continuous casting strand guide device 114 and the horizontal outlet area of ​​the continuous casting strand guide device, two opposing continuous casting strand guide rollers can form a driving roller pair. According to the present invention, exactly one of these roller pairs or the roller pair located at the outlet of the continuous casting strand guide device 114 before the first rolling mill stand 122 is set as a main driving roller pair 118 as an adjustment mechanism for regulating the casting speed of the continuous casting strand 20 by means of a casting speed controller 142. The casting speed controller 142 is designed to regulate the actual casting speed to a specified target casting speed by appropriately changing the power or current of the drive of the main roller pair 118. In this regard, the casting speed controller 142 is a "speed master" or master controller within the meaning of the present invention.

[0019] A rolling mill 120 having at least a first rolling stand 122 for rolling the continuously cast strands 20 is arranged downstream of the casting mill 110 in the casting direction G, wherein the casting mill 110 and the rolling mill 120 are operated in particular in a continuous operating mode in which they are coupled to one another via the continuous continuously cast strands 20 .

[0020] In addition to the main driving roller pair 118 , at least one slave driving roller pair 116 is provided in the casting installation 110 , in particular in its strand guiding device 114 , which is controlled to a specified target torque by means of a torque controller 144 .

[0021] The casting and rolling plant 100 is basically designed to carry out the method according to the invention. The method is explained as follows:

[0022] In the continuous operation mode, the continuous casting strand 20 cast in the crystallizer is guided by the continuous casting strand guide rollers of the continuous casting strand guide device 114 and transported along the casting direction through the casting and rolling equipment 100. By means of the main casting speed controller 142, the actual casting speed of the continuous casting strand 20 is regulated to the specified target casting speed by appropriately changing the power or current of the drive of the main roller pair 118.

[0023] Figure 1 The first embodiment of the casting speed control according to the present invention is shown. In this embodiment, the rotation speed of the driver of the main driving roller pair 118 is defined as a control variable, and the target casting speed is set for the driver of the main driving roller pair 118 in the form of a target rotation speed. In this control, the actual casting speed represented by the actual rotation speed of the driver of the main driving roller pair 118 is controlled to the target casting speed represented by the set target rotation speed of the driver of the main driving roller pair 118.

[0024] Figure 2 An alternative embodiment of the casting speed control according to the invention is shown. In this second embodiment, the speed of the continuous casting strand 20 or the speed of its surface is defined as a control variable. That is, the actual casting speed represented by the actual speed of the continuous casting strand 20 or the actual speed of the surface of the continuous casting strand 20 is controlled to the set target casting speed represented by the set target speed of the continuous casting strand or the surface of the continuous casting strand, wherein the main drive roller pair 118 serves as an adjustment mechanism.

[0025] The following description applies equally to both embodiments of the casting speed control according to the invention: In addition to the main drive roller pair, at least one further roller pair 116 is provided in the casting device 110 as a so-called slave drive roller pair. Only the main drive roller pair 118 is speed-controlled according to the method according to the invention. In contrast, at least one slave drive roller pair 116 is torque-controlled by means of a slave torque controller 144. That is, the actual torque of its rollers is controlled to the set target torque.

[0026] If there are multiple secondary drive roller pairs 116 in the casting device 110 or in the casting direction before the first rolling mill stand 122, then these secondary drive roller pairs, as described above, are each torque-controlled. The target torque of these secondary drive roller pairs 116 then preferably corresponds to the predetermined distribution of the drive moments of these secondary drive roller pairs.

[0027] The casting and rolling plant 100 can be operated not only in the continuous operation mode, in which the continuous cast strand 20 at least enters the first rolling mill stand 122 of the rolling plant 120 and is rolled by the rolling mill stand 122. In terms of time, before the continuous operation mode, the casting and rolling plant can be operated in a startup mode, in which the continuous cast strand 20 is cast in the casting plant 110 and is transported before the first rolling mill stand 122 of the rolling plant. In both operation modes, the continuous cast strand 20 can be operated according to the above reference. Figure 1 and Figure 2 The two embodiments described are used to control the casting speed. Preferably, the target casting speed of the main drive roller pair 118 is then set equal in magnitude and constant in time in the start-up mode and in the continuous operation mode.

[0028] At least one secondary driven roller pair can be provided both in the casting plant 110 and in the rolling plant 120. In a rolling plant, such secondary driven roller pairs are usually formed by working rollers 124 of a rolling mill stand 122, in particular by working rollers of a first rolling mill stand 122 arranged in the casting direction G. It also applies to these secondary driven roller pairs in the rolling plant that they may not be regulated to the casting speed according to the method according to the invention. Rather, they are regulated in terms of torque during the continuous operating mode, that is, the actual torque of the rollers of the secondary driven roller pair 124 in the rolling mill stand is adjusted or regulated to a set target torque.

[0029] For the rollers of the driven roller pair 116 in the strand guiding device 114 and / or for the rollers of the driven roller pair 124 in the rolling mill 120, the torque control is preferably performed by appropriately changing the current in the roller drive. In this case, the current is then changed as a control variable of the drive, so that the actual torque is adjusted or controlled to the required or set target torque.

[0030] As an alternative to this, torque control can also be performed for the rollers of the slave drive roller pair in the continuous casting strand guiding device 114 and / or the rolling equipment 120 by appropriately changing the rotational speed of these rollers as the adjustment variable. That is, the corresponding responsible torque controller 144, 146 stipulates an appropriate change in the rotational speed as the adjustment variable for the rollers of the slave drive roller pair involved, and then sets the current in the drive accordingly to achieve the required rotational speed change. According to another embodiment, at least for any one of the torque controllers 144, 146, the rotational speed changed as the adjustment variable can be maintained at the rotational speed set when changing by means of the lower-level rotational speed controller 148.

[0031] In the case of the upper torque control, by changing the rotational speed as the regulating variable and the optional lower rotational speed control, it is advantageously achieved that the continuous cast strand 20 between the casting device 110 and the first rolling mill stand 122 does not bulge. It is also advantageously prevented that excessive tension is generated in the continuous cast strand 20 between the casting device 110 and the first rolling mill stand 122, and one of the drives of the slave drive roller pairs 116, 124 slips. If the drive torque of the slave drive roller pair 116 in the casting device 110 increases, the first rolling mill stand 122 must rotate faster, that is, a higher rotational speed must be set as the regulating variable. Conversely, if the drive torque of the drive roller pair 116 in the casting device 110 decreases, the first rolling mill stand 122 must rotate correspondingly slower, that is, a lower rotational speed must be set as the regulating variable.

[0032] The target torque of the working rolls 124 of the preferably first rolling mill stand 122 of the rolling mill 120 can be set, for example, as the actual torque of one of the slave drive roll pairs 116 in the strand guiding device 114. Alternatively, the target torque of the working rolls 124 can also be set as the total torque of at least two, preferably all slave drive roll pairs 116 in the strand guiding device 114.

[0033] The total torque is determined by measuring the torques of at least two, preferably all, drive roll pairs 116 before the first rolling stand 122 during the start-up mode before the cast strand enters the first rolling stand, storing them and summing them to a total torque.

[0034] List of reference numerals:

[0035] 100 Casting and rolling equipment

[0036] 110 Casting Equipment

[0037] 112 Crystallizer

[0038] 114 Continuous casting slab guiding device

[0039] 116 The first rolling mill stand before the slave drive roller pair

[0040] 118 Main drive roller pair before the first rolling mill stand

[0041] 120 Rolling equipment

[0042] 122 Rolling Mill Stand

[0043] 124 The working rolls of the rolling mill stand are in the form of slave drive roll pairs

[0044] 142 Main casting speed controller for main drive roller pair

[0045] 144 Slave torque regulator for casting equipment

[0046] 146 Slave torque controller for rolling equipment

[0047] 148 Lower speed controller

[0048] 20 Continuous Casting Billet

[0049] G Casting direction.

Claims

1. A method for operating a casting and rolling plant (100), the casting and rolling plant having a casting plant (110) and a rolling plant (120) arranged downstream of the casting plant (110) along the casting direction (G), the casting plant comprising a crystallizer (112) for casting continuous continuous casting strands (20) and a continuous casting strand guiding device (114) arranged downstream of the crystallizer (112) along the casting direction (G) for guiding the continuous casting strands (20), and the rolling plant having at least one rolling mill stand (122) for rolling the continuous casting strands (20), wherein: The casting device (110) and the rolling device (120) are operated in a continuous operation mode, in which the casting device and the rolling device are coupled to each other via the continuous cast strand (20), and the method comprises the following steps: By appropriately changing the power of the drive of the drive roller pair (118) in the continuous casting strand guide device (114) of the casting device (110) or at its outlet before the first rolling mill stand (122) of the rolling device (120), the actual casting speed of the continuous casting strand (20) is regulated to a set target casting speed, wherein the continuous casting strand (20) is guided between the rollers of the drive roller pair (118) and is conveyed by the rollers through the casting and rolling device (100) in the casting direction (G); It is characterized in that The driving roller pair (118) is a main driving roller pair, and the main driving roller pair serves as the only adjustment mechanism for regulating the casting speed of the continuous casting billet (20); In addition to the main driving roller pair (118), at least one slave driving roller pair (116) is provided upstream of the first rolling mill stand (122); and The actual torque of the roller of the slave driving roller pair (116) is regulated to a set target torque.

2. The method according to claim 1, It is characterized in that The casting and rolling plant (100) is operated in a start-up mode before the continuous operation mode in time, wherein in the continuous operation mode the continuously cast strand (20) at least enters into a first rolling stand (122) of the rolling plant (120) and is rolled by the rolling stand (122), and in the start-up mode the continuously cast strand (20) is cast in the casting plant (110) and is conveyed until before the first rolling stand (122) of the rolling plant (120).

3. The method according to claim 2, It is characterized in that The target casting speed of the main driving roller pair (118) is set to be equal in magnitude and constant over time in the startup mode and in the continuous operation mode.

4. The method according to any one of the preceding claims, It is characterized in that When regulating the casting speed, the rotation speed of the driver of the main driving roller pair (118) is defined as a regulating variable, and the target casting speed is set for the driver of the main driving roller pair (118) in the form of a target rotation speed; or For the regulation of the casting speed, the speed of the continuous casting billet or the speed of the surface of the continuous casting billet (20) is defined as a control variable, and the target casting speed is set for the drive of the main drive roller pair (118) in the form of a target speed of the continuous casting billet or the surface of the continuous casting billet.

5. The method according to any one of the preceding claims, It is characterized in that If there are a plurality of slave drive roller pairs (116) in the casting apparatus (110), target torques of the plurality of slave drive roller pairs (116) are set according to a desired drive torque distribution.

6. The method according to any one of the preceding claims, It is characterized in that At least one slave roller pair is provided in the rolling mill (120), the slave roller pair being in the form of working rollers (124) of one of the rolling mill stands (122) of the rolling mill (120), in particular of the first rolling mill stand (122) along the casting direction (G); and During the continuous operation mode, the actual torque of the rollers of the slave drive roller pair (124) in the rolling mill (120) is regulated to a set target torque.

7. The method according to claim 6, It is characterized in that For the rollers of the slave driven roller pair (116, 124) upstream of the first rolling mill stand (122) and / or in the rolling mill (120), the torque is controlled by appropriately varying the current in the drive of the rollers as a regulating variable.

8. The method according to claim 6, It is characterized in that For the rollers of the slave roller pair before the first rolling mill stand (122) and / or in the rolling equipment (120), the torque is controlled by appropriately changing the rotational speed of the rollers of the slave roller pair (124) as a regulating variable.

9. The method according to claim 8, It is characterized in that For at least one of the torque regulators (144, 146), the rotational speed changed as a regulating variable is maintained at the rotational speed set when the torque is changed by means of a lower-level rotational speed controller (148).

10. The method according to any one of claims 6 to 9, It is characterized in that The target torque of the working rolls (124) of the preferably first rolling mill stand (122) of the rolling equipment (120) is set to the torque of the slave drive (116) before the first rolling mill stand (122), in particular in the continuous casting strand guiding device (114), or to the sum torque of at least two, preferably all slave drives (116) before the first rolling mill stand (122).

11. The method according to claim 10, It is characterized in that The total torque is determined by measuring the torques of at least two, preferably all, slave drive roller pairs (116) before the first rolling stand (122) before the cast continuous casting strand (20) reaches the first rolling stand (122) during the start-up mode, storing them and adding them to the total torque.

12. A computer program product which can be stored in an internal memory of a digital computer and which has software code segments by means of which the steps of the method according to any one of the preceding claims are executed when the computer program product is run on the computer.

13. A casting and rolling equipment (100), comprising: A casting device (110), comprising a crystallizer (112) for casting continuous continuous casting strands (20) and a continuous casting strand guiding device (114) arranged downstream of the crystallizer (112) in a casting direction (G), the continuous casting strand guiding device comprising continuous casting strand guiding rollers for guiding the continuous casting strands (20); A rolling mill (120) is arranged downstream of the casting device (110) along the casting direction (G), the rolling mill having at least one first rolling mill stand (122) for rolling the continuously cast strand (20), wherein: The casting plant (110) and the rolling plant (120) can be operated in a continuous operation mode in such a way that they are coupled to each other via a continuous cast strand (20); as well as A casting speed controller (142), the casting speed controller being used to control the actual casting speed of the continuous casting billet (20) to a set target casting speed by appropriately changing the power of the driver of the driving roller pair, using the driving roller pair in the continuous casting billet guiding device (114) of the casting device (110) or before the first rolling mill stand (122) of the rolling device (120) at its outlet along the casting direction (G); It is characterized in that The driving roller pair is a main driving roller pair (118), and the casting speed controller is a main controller (142); In addition to the single main drive roller pair (118), at least one slave drive roller pair (116) is provided upstream of the first rolling mill stand (122) with reference to the casting direction (G); and At least one torque regulator (144) is provided in the casting device (110), and the torque regulator is used to regulate the actual torque of at least one roller of the driving roller pair (116) before the first rolling mill stand (122) to a set target torque.

14. The casting and rolling equipment according to claim 13, It is characterized in that In the rolling mill (120) there is at least one further slave roller pair in the form of a working roller (124) of one of the rolling mill stands (122).

15. The casting and rolling equipment according to claim 13 or 14, It is characterized in that The casting and rolling plant (100) is used for carrying out the method according to any one of claims 1 to 11.

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