Cooling of the rolled piece before the finishing stand of the hot rolling installation

Abstract

The invention relates to a method for cooling a rolled piece (15) in a cooling section (19) arranged before a finishing mill train (9) of a hot rolling installation (1), the cooling section having at least one cooling device (21, 22, 23) with which a coolant flow of a coolant (35) can be output onto a rolled piece surface (29) of the rolled piece (15). In the method, a coolant flow is output onto the rolled piece surface (29) in each cooling section pass by means of each cooling device (21, 22, 23), the coolant flow being set to a set value which is assigned to the respective cooling device (21, 22, 23) for the cooling section pass. The set value for the cooling section pass is determined in a simulation of the cooling section pass in such a way that a surface temperature of the rolled piece surface (29), determined in the simulation, when output from an action region (31, 32, 33) of the cooling device (21, 22, 23), is not lower than a minimum value for the surface temperature of the rolled piece surface (29).

Description

Technical Field

[0001] The present invention relates to a method and a cooling section for cooling rolled pieces before the finishing mill train of a hot rolling equipment. Background Technology

[0002] Metal parts, such as steel strips, are rolled in hot rolling mills to reduce their thickness. Hot rolling mills often have so-called pre-rolling mill lines and so-called finishing mill lines. In the pre-rolling mill line, the workpiece is rolled into a so-called pre-rolled strip with a pre-rolled strip thickness. The pre-rolled strip is then supplied to the finishing mill line via a so-called intermediate roller table, where the thickness of the workpiece is further reduced from the pre-rolled strip thickness to the final thickness.

[0003] A rolled piece, for example, having a temperature in the range of 1100°C to 1200°C, is supplied to the pre-rolling mill. This can be achieved, for example, by heating the rolled piece to this temperature in a furnace before the pre-rolling mill, or by supplying the pre-heated rolled piece directly to the pre-rolling mill. The rolled piece does not deform in the intermediate roll table, meaning its thickness is not reduced by rolling; instead, the rolled piece is only cooled, that is, the temperature of the pre-rolled strip is reduced, for example, to a temperature in the range of 700°C to 900°C.

[0004] Cooling of the rolled piece in the intermediate roller table is used to limit the entry temperature of the rolled piece as it enters the finishing mill train. The entry temperature is limited for metallurgical reasons, such as to suppress recrystallization in the rolled piece during transport through the finishing mill train, especially in the production of so-called thermomechanically rolled products, such as pipe steel or microalloyed steel, and / or to achieve high surface quality, for example, in the production of automotive body panels or tank panels. Furthermore, it is often advantageous to reach the desired entry temperature for the finishing mill train as quickly as possible during the transport of the rolled piece through the intermediate roller table.

[0005] On the other hand, excessive cooling of the rolled piece in the intermediate roll table can lead to overcooling of the surface area of ​​the rolled piece. This overcooling can cause a phase transition in the near-surface region of the rolled piece, which can impair the product quality of the manufactured product in the rolling process and should therefore be avoided. To prevent this overcooling, it is required that the surface temperature of the rolled piece in the intermediate roll table not fall below a defined minimum.

[0006] EP 2 873 469 A1 discloses an operating method for cooling a flat rolled piece in a cooling section using a cooling device arranged along the cooling section, wherein coolant is output to the rolled piece individually as it is transported through the cooling section. For the cooling device, cooling performance is determined individually by simulating the point transport of the rolled piece through the cooling section, and the cooling device is controlled based on this cooling performance as the rolled piece is transported through the cooling section. Summary of the Invention

[0007] The purpose of this invention is to provide a method and a cooling section for cooling rolled pieces before the finishing mill train of a hot rolling mill, wherein the surface temperature of the rolled piece does not fall below a predetermined minimum value.

[0008] This objective is achieved according to the invention by a method for cooling a rolled piece in a cooling section arranged before the finishing mill of a hot rolling mill, and a cooling section for cooling a rolled piece before the finishing mill of a hot rolling mill.

[0009] The present invention also relates to advantageous design solutions.

[0010] In the method according to the invention, the rolled piece is transported along the cooling section once at a predetermined transport speed or multiple times in alternating directions at separately predetermined transport speeds. Here, the predetermined transport speed can vary over time. However, the transport speed can also be constant over time. The cooling section has cooling devices with working areas, or multiple cooling devices with working areas arranged sequentially along the cooling section, wherein the working areas of adjacent cooling devices are close together, and each cooling device can output a coolant flow of coolant to the surface of the rolled piece within its working area, the coolant flow being set between zero and a maximum value specific to the cooling device.

[0011] In the method according to the invention, a minimum surface temperature for the surface of the rolled piece during transport through the cooling section is received. To comply with the minimum value, a set value for the coolant flow is assigned to each cooling device for each cooling section step (Kühlstreckendurchlauf) passing through the cooling section, and the coolant flow is output to the surface of the rolled piece by each cooling device in each cooling section step, the coolant flow being set to the set value associated with the corresponding cooling device for the cooling section step.

[0012] To determine the setpoints for the cooling section process, the cooling section process, which involves passing through the cooling section at a pre-defined transport speed, is simulated at least once for each section of the rolled piece. Within each simulated cooling section process, each cooling unit is addressed step-by-step: - At the latest immediately following the entry of the rolled section into the working area of ​​the cooling device, receive or determine the pre-defined value for the coolant flow to be output by the cooling device. - Based on the initial enthalpy and / or initial temperature distribution in the rolling section when entering the working region of the cooling device, calculate the enthalpy and / or temperature distribution in the rolling section when exiting the working region of the cooling device according to the physical model, and - The setpoint is determined in such a way that the setpoint will maximize the flow of coolant to be output from the cooling device to the surface of the rolled piece under auxiliary conditions, so that the setpoint does not exceed a predetermined value, and the surface temperature of the rolled piece when output from the effective area of ​​the cooling device, derived from the initial enthalpy distribution and / or initial temperature distribution, or derived from the calculated enthalpy distribution and / or calculated temperature distribution of the rolled piece section, is not lower than a minimum value.

[0013] In the simulation of the cooling section process, for each pair of action zones that are passed adjacent to each other in the cooling section process, the enthalpy distribution and / or the calculated temperature distribution for the first action zone passed through, when exiting from the first action zone, are assigned to the other action zones as the initial enthalpy distribution and / or initial temperature distribution when entering the other action zones. For the first cooling device passed by the rolling section in the cooling section process, the original initial enthalpy distribution and / or the original initial temperature distribution are received.

[0014] In the method according to the invention, each cooling section of the rolled piece is first simulated at least once for each section of the rolled piece, wherein a set value for the coolant flow of all cooling devices is determined in the simulation. This set value is then used to operate the cooling devices in the actual cooling section of the rolled piece. The set value for the cooling devices is determined during the simulation of the cooling section process such that the coolant flow determined by the set value is quasi-maximum under auxiliary conditions, so that the set value does not exceed a predetermined value, and the surface temperature of the rolled piece surface, as determined in the simulation, when output from the operating area of ​​the cooling device, is not lower than a minimum value. The predetermined value for the coolant flow of the cooling devices is determined in the simulation or, for example, received by a higher-level control device.

[0015] "Near-maximum coolant flow" is understood here as the coolant flow that is maximum under the mentioned auxiliary conditions, or approximates the maximum coolant flow within the framework of the design scheme of the regulation technology. This takes into account that in practice, an exact maximization of the coolant flow is not necessary, because the simulation is based on a mathematical model that only models the cooling section and therefore does not map it precisely, thus it is necessary to accept small deviations between the simulation and the actual cooling process in the cooling section. Furthermore, an exact maximization of the coolant flow could lead to unduly high computational costs and hinder the simulation from being performed as quickly as possible.

[0016] Maximizing the coolant flow rate advantageously enables optimized cooling of the rolled piece during transport through the cooling section. A target temperature at the end of the cooling section can be predetermined by setting a value for the coolant flow rate; this target temperature matches the desired entry temperature of the rolled piece into the finishing mill. An auxiliary condition is that the surface temperature of the rolled piece, as determined in the simulation, when exiting the operating area of ​​the cooling device, is not lower than a minimum value for the surface temperature. This auxiliary condition advantageously prevents the aforementioned undercooling of the rolled piece surface during transport through the cooling section, which reduces product quality. Correspondingly, this minimum value is predetermined to avoid such undercooling of the rolled piece surface.

[0017] In the design scheme of the method according to the invention, in each simulated cooling section process of the rolling section, at least one cooling device is provided, and in particular each cooling device is assigned according to the method described above. and The product of The set value, where, This is the value associated with the cooling device in the running index. This value numbers the area of ​​effect of the cooling device according to the order in which the rolled section passes through the cooling device during the cooling section process. Here, It refers to a pre-defined value for the coolant flow to be output by the cooling device. It is the surface temperature of the rolled piece as it enters the effective zone of the cooling device, derived from the initial enthalpy distribution and / or initial temperature distribution. It refers to the minimum surface temperature of the rolled piece, and It is a pre-defined backup temperature difference. The following function is for... Zero, targeting It is one, and in the interval It increases strictly in a monotonically increasing manner.

[0018] In the design scheme mentioned above according to the method of the present invention, the auxiliary condition in which the set value does not exceed a predetermined value is achieved by the following means: function Not exceeding value one. The auxiliary condition that the surface temperature of the rolled piece, when output from the effective area of ​​the cooling device, is not lower than the minimum value can be achieved by appropriately selecting a spare temperature difference. This is achieved by quasi-maximizing the coolant flow due to the function. It increases monotonically from zero to one.

[0019] In an alternative design to the aforementioned design scheme according to the method of the present invention, a setpoint is determined for at least one cooling device, and more particularly for each cooling device, in each simulated cooling section process by: firstly, calculating the surface temperature of the rolled piece surface when exiting the working area of ​​the cooling device with respect to a predetermined value for the coolant flow of the cooling device. If the surface temperature calculated for the predetermined value is not lower than a minimum value, the setpoint is made equal to the predetermined value. Otherwise, the surface temperature when exiting the working area is iteratively calculated for at least one coolant flow that is less than the predetermined value in order to determine a setpoint for the coolant flow for which the calculated surface temperature when exiting the working area is consistent with the minimum value with sufficient accuracy. "Sufficiently accurate consistency" is understood, for example, as consistency other than absolute or relative deviations, the magnitude of which does not exceed a predetermined tolerance value.

[0020] The design scheme described above according to the method of the present invention also achieves the auxiliary conditions mentioned above. If the surface temperature actually matches the minimum value after its iterative calculation, this design scheme achieves precise maximization of the coolant flow. However, for the reasons mentioned above, slightly exceeding the minimum value is acceptable and constitutes a quasi-maximization of the coolant flow.

[0021] In another design of the method according to the invention, for each cooling device, the maximum value of the coolant flow is received, which is specific to the respective cooling device, as a predetermined value for the coolant flow in each simulated cooling section process.

[0022] The design scheme mentioned above according to the method of the present invention enables the cooling of the rolled piece as quickly as possible in the cooling section process by setting each predetermined value to the maximum value of the coolant flow specific to the corresponding cooling device.

[0023] In a design alternative to the aforementioned design scheme according to the method of the present invention, for the simulation of the cooling section process of the rolling section, the maximum total amount of coolant output to the surface portion of the rolling section belonging to the rolling section surface during the cooling section process is determined, and a predetermined value of the coolant flow for the simulated cooling section process is determined based on the total amount of coolant and the transport speed predetermined for the cooling section process. Here, the expression "cooling dose" always means the integral of the coolant flow over the operating time of the observed rolling section through the area of ​​action of one or more cooling devices. It is also possible that the coolant flow acting on the rolling section does not always have the same effect. Therefore, the cooling dose refers to the weighted integral based on the cooling effect of the coolant flow. The physical unit of coolant flow is, for example, m. 2 / s, corresponding to the cooling device per meter width in m 3 The specific coolant flow rate is measured in m / s. The physical unit of coolant dosage is therefore m. 2 Corresponding to the cooling device per meter width in m 3 The calculated cooling dose.

[0024] In the aforementioned design scheme according to the method of the present invention, the cooling effect of the entire cooling section process and thus the target temperature of the rolled piece after the cooling section process can be predetermined by the total amount of coolant. Then, a predetermined value of coolant flow for the simulated cooling section process is determined based on the total amount of coolant, thereby allocating the total amount of coolant to the cooling device by the predetermined value.

[0025] In a continuation of the design scheme mentioned above according to the method of the invention, the target average temperature of the rolled piece after the cooling section process is received. In each simulation of the cooling section process of the rolled piece segment, the average temperature of the rolled piece segment at the end of the cooling section process is calculated, and if the calculated average temperature is not sufficiently accurate to match the target average temperature, the total amount of coolant is changed for subsequent simulations of the cooling section process of the rolled piece segment so that the calculated average temperature is adapted to the target average temperature. This advantageously enables iterative changes in the total amount of coolant to achieve the target average temperature with sufficient accuracy at the end of the cooling section process. "Sufficiently accurate consistency between the calculated average temperature and the target average temperature" is understood, for example, as consistency other than absolute or relative deviations, the magnitude of which does not exceed a predetermined tolerance value. In this continuation of the design scheme, the target average temperature of the rolled piece is thus predetermined as the target temperature of the rolled piece after the cooling section process, and the total amount of coolant is adapted to the target average temperature.

[0026] Furthermore, it is possible to configure the allocation of coolant residual amount to each cooling device in the simulation of the cooling section process of the rolling section. Here, the total amount of coolant allocated to the first cooling device in the cooling section process is used as the coolant residual amount. The coolant residual amount is allocated to each additional cooling device by subtracting the following cooling dose from the coolant residual amount of the previous cooling device in the cooling section process. This cooling dose is output by the previous cooling device to the surface portion of the rolling section belonging to the rolling section surface according to the set value of the coolant flow obtained for that cooling device. Then, according to... and product To determine the predetermined value of the coolant flow rate of the cooling device, wherein, It is the maximum value of the coolant flow rate of the cooling device. It refers to the amount of coolant residue belonging to the cooling device, and It is the maximum amount of cooling that can be delivered to the surface portion of the rolled piece in the cooling section process using a cooling device. Indicates 1 and The minimum of these two values. In this design scheme according to the method of the present invention, a predetermined value for the coolant flow of the cooling device is determined during the simulation of the cooling section process by allocating a coolant residual amount to each cooling device and determining the predetermined value for the cooling device based on the coolant residual amount.

[0027] Alternatively, if a setpoint lower than a predetermined value received by the cooling device is determined for the cooling unit in the simulation of the cooling section process of the rolling section, and if at least one subsequent cooling device arrives later in the cooling section process, and the predetermined value received by that subsequent cooling device is less than the maximum value of the coolant flow of that cooling device, then the predetermined value is increased for at least one such subsequent cooling device so that the total amount of cooling output to the surface portion of the rolling section belonging to the rolling section to be delivered in the cooling section process is matched with the total amount of coolant determined for the cooling section process. This design of the method according to the invention is based on the predetermined value received at the start of the simulation. If the setpoint determined for the cooling device in the simulation is lower than the associated predetermined value, the predetermined value is matched as necessary in the simulation. When matching the predetermined value, the predetermined value for the subsequent cooling device is increased as much as possible so that the cooling effect of the cooling section process is matched with the cooling effect corresponding to the total amount of coolant.

[0028] In another design embodiment of the method according to the invention, in order to calculate the enthalpy distribution and / or temperature distribution in the rolling section when output from the working area of ​​the cooling device, a one-dimensional heat conduction equation describing the enthalpy distribution and / or temperature distribution along the thickness direction of the rolling section is solved in a simulation of the cooling section process of the rolling section. To solve the heat conduction equation, boundary conditions are considered, for example, that parameterize the cooling of the rolling section due to thermal radiation, the coolant output to the surface of the rolling section, the heat discharged to the surrounding air, and the heat discharged to the transport rolls that transport the rolling section. Here, the thickness direction of the rolling section is the direction from the upper surface to the lower surface of the rolling section, or conversely, the direction from the lower surface to the upper surface of the lower rolling section.

[0029] The design scheme mentioned above in the method of the present invention takes into account that the heat flow within the rolled piece along the longitudinal or transverse direction is negligible compared to the heat flow along the thickness direction of the rolled piece. Therefore, to calculate the enthalpy and / or temperature distribution in the rolled piece section, a one-dimensional heat conduction equation describing the enthalpy and / or temperature distribution along the thickness direction of the rolled piece can be used with sufficient accuracy. This significantly reduces computational cost and time compared to using two-dimensional or three-dimensional heat conduction equations. The mentioned boundary conditions take into account the main influences on the development of the enthalpy and temperature distribution in the rolled piece.

[0030] In another embodiment of the method according to the invention, at at least one measuring location through which the rolling section passes before the cooling section process, the surface temperature of the surface portion of the rolling surface belonging to the rolling section is measured, and the simulated original initial enthalpy distribution and / or original initial temperature distribution for the cooling section process of the rolling section is determined based on at least one measured surface temperature.

[0031] The method according to the present invention can also be performed on the upper or lower surface of the rolled piece, or on the upper and lower surfaces of the rolled piece individually.

[0032] The cooling section according to the invention, used for cooling the rolled stock before the finishing mill train of a hot rolling mill, includes: - A cooling device, or multiple cooling devices arranged sequentially along the path of the cooling section, which can individually output coolant flows to the surface of the rolled piece. The coolant flow rate can be set between zero and a maximum value specific to each cooling device. - Multiple transport rolls, these transport rolls are configured to transport the rolled piece along the cooling section path through the cooling section, and - A control unit configured to operate the cooling section according to the method of the present invention as described above.

[0033] In the design of the cooling section according to the invention, which has multiple cooling devices, the cooling devices are arranged along the cooling section stroke according to the maximum value of the coolant flow they can output, such that the maximum value monotonically decreases toward the finishing mill line. This advantageously enables rapid cooling of the rolled piece at the beginning of the cooling section. Furthermore, since the surface temperature of the rolled piece is usually already at a minimum in the later part of the cooling section and therefore only lower cooling performance is required there, the cooling devices in the later part of the cooling section can be implemented more easily and at a lower cost than those in the earlier part of the cooling section. Attached Figure Description

[0034] The following description, in conjunction with the embodiments, will make the features, characteristics, and advantages of the present invention described above, and the methods and means of achieving these features, characteristics, and advantages, clearer and more apparent. These embodiments are explained in more detail with reference to the accompanying drawings. As shown herein: Figure 1 The hot rolling equipment is shown schematically. Figure 2 A flowchart of the method according to the present invention is shown. Figure 3 A flowchart of a first embodiment of the method steps according to the present invention is shown. Figure 4 A flowchart of a second embodiment of the method steps according to the present invention is shown. Figure 5 A flowchart of a third embodiment of the method steps according to the present invention is shown. Figure 6 A flowchart of a fourth embodiment of the method steps according to the present invention is shown. Figure 7 The temperature trend in the rolling section before and during the cooling process is shown. Detailed Implementation

[0035] Corresponding components are given the same reference numerals in the accompanying drawings.

[0036] Appendix Figure 1 ( Figure 1 The diagram schematically illustrates a hot rolling mill 1. The hot rolling mill 1 includes a heating furnace 3, a pre-rolling mill line 5, an intermediate roller table 7, a finishing mill line 9, an exit cooling zone 11, and a coiler zone 13. The rolled piece 15 is transported via the hot rolling mill 1 from the heating furnace 3 to the coiler zone 13.

[0037] The heating furnace 3 is arranged in front of the pre-rolling mill line 5 and is configured to heat the rolled piece 15 to a determined temperature, for example, in the range of 1100°C to 1200°C.

[0038] The pre-rolling mill 5 has at least one pre-rolling mill stand 17. In the pre-rolling mill 5, the workpiece 15 is rolled into a pre-rolled strip with a pre-rolled strip thickness, which is, for example, in the range of 30 mm to 170 mm.

[0039] The rolled piece 15 is transported from the pre-rolling mill line 5 to the finishing mill line 9 at a predetermined transport speed via the intermediate roller table 7. The intermediate roller table 7 has an embodiment of a cooling section 19 according to the invention. The cooling section 19 includes: a plurality of cooling devices 21, 22, 23 arranged sequentially to each other along the cooling section travel path; a plurality of transport rollers 25 configured to transport the rolled piece 15 along the cooling section travel path through the cooling section; and a control unit 27 configured to operate the cooling section 19 according to an embodiment of the method according to the invention for cooling the rolled piece 15. An embodiment of the method according to the invention is described below. Figures 2 to 6 To describe. In Figure 1 The example shown is a cooling section 19 having three cooling devices 21, 22, and 23. However, the cooling section 19 can also have other numbers of cooling devices 21, 22, and 23.

[0040] Each cooling device 21, 22, 23 can output a coolant flow of coolant 35 to the rolled surface 29 of the rolled piece 15 within its effective regions 31, 32, 33. This coolant flow can be set between zero and a maximum value specific to each cooling device 21, 22, 23. The coolant 35 is, for example, water. Figure 1 In this embodiment, the workpiece surface 29 is the upper surface of the workpiece 15. In other embodiments, the workpiece surface 29 can be the lower surface of the workpiece 15, wherein the cooling devices 21, 22, and 23 are then arranged below the workpiece 15. Furthermore, the cooling section 19 can have cooling devices 21, 22, and 23 not only for the upper surface of the workpiece 15 but also for the lower surface. In the latter case, the method according to the invention is implemented separately for the upper surface and the lower surface of the workpiece 15.

[0041] Each cooling device 21, 22, 23 is constructed, for example, as a cooling beam extending along the width of the rolled piece 15 and having multiple nozzles capable of discharging coolant 35 onto the surface 29 of the rolled piece. The working areas 31, 32, 33 are thus assigned to the cooling devices 21, 22, 23 such that the working areas 31, 32, 33 of adjacent cooling devices 21, 22, 23 are adjacent to each other. For example, the cooling devices 21, 22, 23 are arranged along the cooling section stroke corresponding to the maximum value of the coolant flow they can output, such that the maximum value monotonically decreases toward the finishing mill line 9.

[0042] Furthermore, in the intermediate roller conveyor 7, a measuring device 37 is arranged at the measuring section 39 before the cooling section 19. This measuring device is designed to detect the surface temperature of the rolled surface 29. For this purpose, the measuring device 37 includes, for example, a pyrometer.

[0043] The finishing mill 9 includes multiple finishing mill stands 41 and finishing mill cooling devices 43. These cooling devices are arranged between two finishing mill stands 41, and can respectively output finishing mill coolant 45 to the surface 29 of the rolled piece. In the finishing mill 9, the thickness of the rolled piece 15 is reduced to the final thickness using the finishing mill stands 41.

[0044] An outlet cooling device 47, 49 is arranged in the outlet cooling zone 11, which allows the outlet coolant 51 to be discharged onto the surface 29 of the rolled piece. The rolled piece 15 behind the finishing mill row 9 is cooled in the outlet cooling zone 11.

[0045] At least one rolled piece coiler 53 is arranged in the coiler area 13, which is configured for coiling rolled piece 15.

[0046] Appendix Figure 2 ( Figure 2 The diagram shows a flowchart of a method according to the invention having method steps 100, 200, 300 for cooling the rolled piece 15 in the cooling section 19.

[0047] In the first method step 100, the control unit 27 receives the minimum surface temperature of the rolled piece 15 for the surface 29 of the rolled piece 15 during transport through the cooling section 19. Minimum value For example, it can be predetermined by a higher-level control device (not shown) or by the operator of hot rolling equipment 1. Minimum value The surface temperature of the rolled piece 15 should not be lower than the surface temperature of the rolled piece surface 29 during the transport of the rolled piece 15 through the cooling section 19.

[0048] In the second method step 200, for the cooling section process of the rolled piece 15 passing through the cooling section 19, each cooling device 21, 22, 23 is assigned a set value for the coolant flow to be output from the cooling devices 21, 22, 23 to the surface 29 of the rolled piece. An embodiment of the second method step 200 is described below according to... Figures 3 to 6 Let me describe it in more detail.

[0049] In the third method step 300, a coolant flow is output to the surface 29 of the rolled piece in the cooling section process by means of each cooling device 21, 22, 23, the coolant flow being set to the set value of the corresponding cooling device 21, 22, 23 assigned to the cooling section process in the second method step 200.

[0050] Method steps 200 and 300 can also be performed multiple times, thereby changing the settings of cooling devices 21, 22, and 23 as necessary during the transport of the rolled piece 15 through the cooling section 19. This is in Figure 2The arrow symbol shown in the middle is indicated by a dashed line.

[0051] The rolled piece 15 is, for example, divided into multiple rolled piece sections that pass sequentially through the working areas 31, 32, and 33 of the cooling devices 21, 22, and 23, and method steps 200 and 300 are performed progressively for each rolled piece section. In this case, in the second method step 200, for each rolled piece section passing through the cooling section of the cooling section 19, a set value is assigned to each cooling device 21, 22, and 23 for the portion of the coolant flow to be output from the cooling devices 21, 22, and 23 to the rolled piece surface 29 belonging to the rolled piece section.

[0052] In the third method step 300, coolant is flowed to the portion of the rolling section that is output to the surface 29 of the rolling section by means of each cooling device 21, 22, 23 in the cooling section process of the rolling section. This coolant flow is set to the set value of the corresponding cooling device 21, 22, 23 assigned to the cooling section process of the rolling section in the second method step 200. Here, it is preferable that each cooling device 21, 22, 23 takes into account the following delay duration, which occurs between changing the set value of the cooling device 21, 22, 23 and changing the coolant flow actually output by the cooling device 21, 22, 23 to the changed set value. The delay duration is such that the time point at which the set value of the cooling device 21, 22, 23 is changed is earlier than the time point at which the cooling device 21, 22, 23 enters the working area 31, 32, 33 of the rolling section by the delay duration.

[0053] Appendix Figure 3 ( Figure 3 The diagram illustrates a first embodiment of a second method step 200, which includes sub-steps 201 to 216 for determining set values ​​for cooling devices 21, 22, and 23 for a cooling section process of the rolled piece 15 passing through cooling section 19. Here, the cooling section process, having a transport speed predetermined for the cooling section process, is simulated at least once for a section of the rolled piece 15. (Running Index) The functional areas 31, 32, and 33 of these cooling devices 21, 22, and 23 are numbered according to the order in which the workpiece passes through the cooling devices in the cooling section process. Indicate the number of cooling devices 21, 22, and 23 (as already implemented above). Figure 1 Only three cooling devices 21, 22, and 23 are shown as examples; the method is described below with respect to a general number of cooling devices 21, 22, and 23.

[0054] In the first sub-step 201, the target average temperature of the rolled section is received after the cooling section process, that is, after passing through all working zones 31, 32, and 33. The second sub-step 202 is performed after the first sub-step 201.

[0055] In the second sub-step 202, the maximum total amount of coolant 35 received during the cooling section process is the amount of coolant output to the surface portion of the rolled section 29 belonging to the rolled section. The third sub-step 203 is performed after the second sub-step 202.

[0056] In the third sub-step 203, the total amount of coolant is... As an initial value allocated to the coolant residue And assign the value 1 as the initial value to the running index. After the third sub-step 203, the index value is targeted for execution. To implement the fourth sub-step 204.

[0057] In the fourth sub-step 204, the material along the thickness direction of the rolled section is received or adopted upon entering the section with the running index. The initial temperature distribution within the corresponding current value's effective range 31, 32, and 33. The thickness direction of the rolled piece is perpendicular to the transport direction of the rolled piece 15 through the cooling section 19 and extends from the upper surface to the lower surface of the rolled piece 15. Let represent the variable along the thickness direction of the rolled piece, where It is a point on the upper surface of the rolled piece 15, and It is the point on the lower surface of the rolled piece 15. Points opposite each other along the thickness direction of the rolled piece.

[0058] For running index values As the initial temperature distribution, it receives the original initial temperature distribution. The original initial temperature distribution is derived, for example, from the surface temperature of the rolled piece surface 29 detected by the measuring device 37 and / or from the heating temperature of the furnace 3. For example, the initial temperature distribution... The model is a parabolic temperature distribution along the thickness direction of the rolled piece, which is located between the assumed core temperature in the middle between the upper and lower surfaces of the rolled piece 15 and the surface temperature detected by the measuring device 37, wherein the core temperature is derived, for example, from the heating temperature of the heating furnace 3.

[0059] For each running index value Using temperature distribution As the initial temperature distribution In the previous implementation of sub-step 207, the issue of having a running index value was already addressed. The temperature distribution within the effective regions 31, 32, and 33 is obtained as follows: (1).

[0060] As the initial temperature distribution Alternative or additional solutions can be found in sub-step 204 for the corresponding current running index value in a similar manner. To receive or adopt the initial enthalpy distribution The fifth sub-step 205 is performed after the fourth sub-step 204.

[0061] In the fifth sub-step 205, determine the target index for the running index. The corresponding current value of the coolant flow of cooling devices 21, 22, and 23 is the predetermined value. Therefore, for example, the maximum cooling dose that can be delivered to the surface portion of the rolled section 29 of the rolled piece surface by cooling devices 21, 22, and 23 during the cooling section process is determined. Maximum cooling dose In particular, it depends on the maximum value of the coolant flow that can be output, which is specific to cooling devices 21, 22, and 23. And it depends on a pre-defined transport speed. Pre-defined value. Then it is defined as the maximum value. with 1 and The minimum of these two values The product of: (2).

[0062] In other words, if the amount of coolant remaining... The current value is greater than the maximum cooling dose. Or equal to the maximum cooling dose Then the value is predetermined. The maximum value of the coolant flow output specific to cooling devices 21, 22, and 23. Consistent. Otherwise, a pre-defined value. It is the amount of coolant residue. The current value and the rolling section are linked through a running index. The effective transit time of the current value's scope area 31, 32, and 33 The quotient. The sixth sub-step 206 is performed after the fifth sub-step 205.

[0063] In the sixth sub-step 206, the coolant flow is targeted to have an operating index. The corresponding current values ​​of the cooling device settings 21, 22, and 23 The pre-defined value determined for the coolant flow in the previous fifth sub-step 205 is assigned. Use this as the initial value. Perform the seventh sub-step 207 after the sixth sub-step 206.

[0064] In the seventh sub-step 207, the calculation is performed along the thickness direction of the rolled section from the section with the running index. The temperature distribution output during the corresponding current value's effective range 31, 32, and 33. The temperature distribution is calculated based on the following physical model. This physical model describes the temporal evolution of temperature distribution in the rolling zone using a one-dimensional thermal conductivity equation. The initial temperature distribution, used as an adjunct to the boundary conditions mentioned below, is applied to the temperature distribution upon entering the corresponding action regions 31, 32, and 33. To solve the heat conduction equation.

[0065] As temperature distribution Alternative or additional schemes, if the initial enthalpy distribution associated with entering the action regions 31, 32, and 33 was received or adopted during the previous implementation of the fourth sub-step 204. Then, in the seventh sub-step 207, the rolling section can be similarly calculated from the section with the running index. The enthalpy distribution when outputting the corresponding current value in the applicable regions 31, 32, and 33. .

[0066] The simplified form of the heat conduction equation is: (3).

[0067] Here, The thermal conductivity of rolled piece 15 is, where, Its thermal conductivity, It is its density, and This indicates its heat capacity.

[0068] For the thermal conductivity equation (3), the boundary conditions need to be applied to the upper surface of the rolled piece 15. heat flux density And for the lower surface heat flux density For example, when used on the upper surface: (4a) And for use on the lower surface: (4b) Here, It is the average transport speed during the passage through the area of ​​effect, hereinafter referred to as transport speed. It is the emissivity of the thermal radiation on the upper surface, and It is the emissivity of the thermal radiation on the lower surface, which is less than the emissivity due to the reflection of thermal radiation at the conveyor roller 25. . and This describes the cooling effect of the surrounding air as the surface temperature of the rolled piece 15 at its upper surface changes. Or the surface temperature at the lower surface of the rolled piece 15 Ambient temperature and transportation speed A changing function. This describes the cooling effect of the transport roller 25 as a function of surface temperature. Ambient temperature and transportation speed A changing function. It describes the value of the running index. The cooling effect of the upper cooling devices 21, 22, and 23, that is, the cooling devices 21, 22, and 23 that cool the upper surface of the rolled piece 15, varies with the surface temperature. Transportation speed Coolant temperature and the cooling devices 21, 22, and 23 pass through the set value A function of the given coolant flow variation. Correspondingly, it describes the value of the running index. The cooling effect of the cooling devices 21, 22, and 23 on the lower side varies with the surface temperature. Transportation speed Coolant temperature and the cooling devices 21, 22, and 23 pass through the set value A function of the given coolant flow variation.

[0069] Functions Separate them so that parameterization can be simplified, for example, in the following way: (4c) One of the features is: cooling effect. With transport speed and the corresponding surface temperature or A more easily describable correlation; cooling effect With coolant temperature The correlation between the two; and the cooling effect. With running index value The coolant flow of the cooling devices 21, 22, 23 on the upper or lower side or The relevance of this. In the portion of the cooling section where no coolant flow is output from the upper cooling devices 21, 22, 23 to the rolled piece 15, it is applicable to... Correspondingly, in the portion of the cooling section where no coolant flow is output from the lower cooling devices 21, 22, 23 to the rolled piece 15, it is suitable for... .

[0070] When the method according to the invention is performed on the upper and lower cooling devices 21, 22, 23, the method is performed individually on the upper cooling devices 21, 22, 23 and the lower cooling devices 21, 22, 23. Figure 3 Therefore, the cooling devices 21, 22, and 23 on the upper side are suitable for... And the cooling devices 21, 22, and 23 on the lower side are correspondingly adapted to etc., including the operating index for the upper cooling devices 21, 22, and 23. The operating range can be compared with the operating index of the cooling devices 21, 22, and 23 on the lower side. They are distinguished by their operating range.

[0071] The alternative form of the heat conduction equation is: (5) In equation (5), This refers to the phase fraction of the rolled piece 15, such as the proportion of austenite, ferrite, cementite, and / or other phases. The phase fraction will never be negative and its sum is always one. (Parameter) It is enthalpy density, where, applicable to Furthermore, the enthalpy density at the corresponding phase fractions... Temperature of the associated There exists a known correlation for each phase fraction, that is, temperature. It is the enthalpy density fraction. It is a strictly monotonically increasing function. Here, because of the location The temperature at that point can only have one value that is the same for all phase fractions, so it is applicable to By solving this system of equations, the function can be calculated. Correspondingly, it can improve thermal conductivity. Expressed as enthalpy density Sum of phases The function. Parameters This indicates that the density of rolled piece 15 is assumed to be the same for all phase fractions.

[0072] Here, the phase fraction can be calculated according to requirements, especially in conjunction with the solution of the heat conduction equation. For example, a system of coupled differential equations can be set up for the phase fraction. (6).

[0073] Using the boundary conditions according to equations (4a) and (4b) for the initial temperature distribution Or the initial enthalpy distribution and initial phase fraction To solve equation (3) or equations (5) and (6) in order to calculate the rolling section in the section with the running index. The temperature distribution output during the corresponding current value's effective range 31, 32, and 33. or enthalpy distribution and phase fraction .

[0074] The functions passed into equations (4a) and (4b) , , It can be appropriately parameterized in a manner known from existing technology, for example, as a so-called B-spline. In some cases, closed-form representations can also be proposed. For this purpose, see, for example, the publication "Modelling of heat transfer in hot strip mill runout table cooling" by W. Timm et al. (2002), Steel Research, 73: 97-104. In that publication, in equation (6) , , Set to heat flux constant respectively and dimensionless correction function The product of, where, index The corresponding cooling method (by air, coolant or transport roller) is indicated. In addition, see, for example, the equations (7) to (9) for cooling by air, the equations (11) to (14) for cooling (different types) by coolant, and the equation (10) for cooling by transport roller in the previously mentioned publications.

[0075] The eighth sub-step 208 is performed after the seventh sub-step 207.

[0076] In the eighth sub-step 208, the inspection is performed at point 29 on the surface of the rolled piece, using the running index. The temperature calculated in the seventh sub-step 207 when the corresponding current value is output in the scope of regions 31, 32, and 33. Does it exceed the minimum value? Or equal to the minimum value (In the case where the surface 29 of the rolled piece is the lower surface of the rolled piece 15, here) pass To replace, or to adapt to coordinates in this way The choice makes (This refers to the lower surface of the rolled piece 15). If this is not the case, proceed to the ninth sub-step 209. Otherwise, proceed to the tenth sub-step 210.

[0077] If the surface 29 of the rolled piece is from the running index The calculated surface temperature is below the minimum value when the corresponding current value is output in the applicable region 31, 32, and 33. In other words, if targeting the running index The current setting value of this value If the value is too high, then the ninth sub-step 209 is always executed. Therefore, in the ninth sub-step 209, for example, Newton's method is used to set the value as follows. Assign a new (smaller) value, so that the new set value The calculated surface temperature approximates the minimum value. Then, the seventh sub-step 207 and the eighth sub-step 208 were implemented, meaning that for the new set value... To calculate from the running index The current value is the surface temperature output within the applicable region 31, 32, and 33. This process is repeated until the calculated surface temperature approaches the minimum value. The temperature is consistent with, or for example, slightly exceeds, the minimum value by a maximum of 10°C, preferably a maximum of 5°C. Then, the tenth sub-step 210 is performed.

[0078] In the tenth sub-step 210, the amount of coolant residue is changed. The value is determined by subtracting the corresponding set value from the previous value. Cooling dose The cooling dose is determined by having an operating index. The current value of the cooling device 21, 22, 23 is output to the surface portion of the rolled section of the workpiece surface 29. Cooling dosage For example, it can be followed (7) To calculate. The eleventh sub-step 211 is performed after the tenth sub-step 210.

[0079] In the eleventh sub-step 211, the index is run. Has the current value reached the final value? In other words, whether the simulated cooling process has ended. If not, proceed to sub-step 212. Otherwise, proceed to sub-step 213.

[0080] The index will be run in the twelfth sub-step 212. The value is increased. Then, the running index is targeted. The new value is implemented in the fourth sub-step 204.

[0081] In sub-step 213, the average temperature of the rolled section after the simulated cooling process is calculated, that is, after the simulated process passing through all action zones 31, 32, and 33. This average temperature is calculated, for example, according to... (8) The temperature distribution calculated during the previous implementation of sub-step 207 To calculate. According to equation (8), the calculated average temperature after traversing all action zones 31, 32, and 33 in the simulation is: from the running index value The average temperature of the rolled piece 15 is calculated when it is output in the working area, that is, when it is output in the working area that is last passed through in the cooling section process. The fourteenth sub-step 214 is performed after the thirteenth sub-step 213.

[0082] In the fourteenth sub-step 214, the average temperature calculated during the previous thirteenth sub-step 213 is verified. Whether the target average temperature of the rolled section after the cooling process is achieved with sufficient precision Consistency. "Sufficiently precise consistency" is understood, for example, as consistency other than absolute or relative deviations, whose magnitude does not exceed a pre-defined tolerance value. If the average temperature... Not accurate enough with the target average temperature If they match, then proceed to sub-step 215 after sub-step 214. Otherwise, proceed to sub-step 216 after sub-step 214.

[0083] If the calculated average temperature after the simulated cooling section process... Not accurate enough with the target average temperature If consistent, proceed to sub-step 215. If the calculated average temperature... Exceeding the target average temperature This indicates the total amount of coolant on which the simulated cooling section process is based. Too small. If the calculated average temperature Below the target average temperature This indicates the total amount of coolant on which the simulated cooling section process is based. Too large. Therefore, in the fifteenth sub-step 215, for example, depending on the calculated average temperature... With the target average temperature The amount of deviation is used to change the total amount of coolant. The value of . Therefore, the calculated average temperature after the next simulated cooling stage process. Able to approach the target average temperature It is possible to improve the total amount of coolant in the later simulated cooling process, for example, using Newton's method. Adaptation.

[0084] After the fifteenth sub-step 215, the total amount of coolant The new value is used to implement the third sub-step 203, that is, based on the total amount of coolant. The changed value was used to begin another simulation of the cooling section process in the rolling mill section. This was consistently based on the total amount of coolant. The value of the change is used to repeat the simulation of the cooling section process until the calculated average temperature after the simulated cooling section process is reached. Sufficiently accurate with the target average temperature Consistent, or total amount of coolant The value is zero, or it reaches or exceeds the maximum value. or coolant residue After implementing sub-step 210, targeting It did not become zero, meaning the initial total amount of coolant... Too large. Maximum value. It is the maximum amount of cooling that can be output to the portion of the rolled section belonging to the rolled section surface 29 by all cooling devices 21, 22, and 23 in the cooling section process of the rolled section (at a transport speed pre-given for the cooling section process).

[0085] If the calculated average temperature after the simulated cooling section process... Sufficiently accurate with the target average temperature If consistent, then the sixteenth sub-step 216 is performed after the fourteenth sub-step 214 of the simulated cooling section process.

[0086] If the total amount of coolant If the value becomes zero, then assign a value to each setpoint. Assign a zero value, that is, set And then proceed to the sixteenth sub-step 216. If the total amount of coolant The value reaches or exceeds the maximum value. Then assign each set value Assign the maximum value specific to the corresponding cooling devices 21, 22, and 23. In other words, setting And then proceed to the sixteenth sub-step 216. Total coolant volume It becomes zero or reaches or exceeds the maximum value. The situation in Figure 3 and Figure 4 It is not shown for reasons of clarity. This is a special case because... In this case, it means that the cooling of the rolled piece 15 is not activated at all in the cooling section 19, and In this case, it means that the rolled piece 15 is cooled to the maximum feasible level in the cooling section 19, in which each cooling device 21, 22, 23 outputs the maximum feasible coolant flow specific to the cooling device 21, 22, 23.

[0087] The second method step 200 ends in the sixteenth sub-step 216, and the set value of the coolant flow determined at the end of method step 200 is stored for each cooling device 21, 22, 23. In the third method step 300, the coolant flow of the corresponding cooling devices 21, 22, and 23 is set to the set value. .

[0088] Appendix Figure 4 ( Figure 4 This illustrates a second embodiment of method step 200. This embodiment is consistent with... Figure 3 The first embodiment described differs only in the modification of sub-step 206 and the omission of sub-steps 208 and 209. Therefore, only descriptions and comments are given below relative to the embodiments described below. Figure 3 Variations of the first embodiment described.

[0089] In this embodiment, in sub-step 206, during the simulated cooling section process in the rolling section, the coolant flow is directed towards a running index. The corresponding current values ​​of the cooling device settings 21, 22, and 23 according to (9) To determine. In equation (9) It is a predefined value, which was already specified for the running index during the previous implementation of sub-step 205. The current value of the coolant flow of cooling devices 21, 22, and 23 is determined. It is the surface temperature of the rolled piece surface 29 when it enters the working areas 31, 32, and 33 of the cooling devices 21, 22, and 23, which is derived from the temperature distribution received during the previous sub-step 204. This is derived from equation (9). When the surface 29 of the rolled piece is the lower surface of the rolled piece 15, then equation (9) and... Figure 4 middle, pass To replace, or to adapt to the choice of coordinate x, so that This indicates the lower surface of the rolled piece 15.

[0090] The following function is for Zero, targeting It is one, and in the interval It is strictly monotonically increasing. For example, The function in the interval According to (10) To define.

[0091] It is the minimum value of the surface temperature of the surface 29 of the rolled piece 15 during the transport of the rolled piece 15 through the cooling section 19, received in the first method step 100. It is a backup temperature difference, which is given in advance so that even when the surface temperature of the rolled piece surface 29 when entering the operating region 31, 32, 33 is greater than And by having a running index value The coolant flow output from cooling devices 21, 22, and 23 to the surface 29 of the rolled piece is the largest, that is, the maximum value specific to cooling devices 21, 22, and 23. At that time, the surface 29 of the rolled piece is from the running index value The surface temperature output from the cooling devices 21, 22, and 23 within their operating areas 31, 32, and 33 will not be lower than the minimum value. . For example, it can be determined in a separate simulation of the cooling section process of rolled piece 15 or based on a mathematical model of the variation of the cooling section 19 with the heating temperature of the heating furnace 3 and the conveying speed of rolled piece 15. Backup temperature difference Able to rely on running indexes The value means that a different backup temperature difference can be given in advance for cooling devices 21, 22, and 23 that are different from each other.

[0092] Method step 200 in Figure 4 The second embodiment shown is compared to Figure 3The first embodiment shown is simpler because it omits sub-steps 208 and 209, and therefore the potential iterations of sub-steps 207 to 209. In particular, the second embodiment of method step 200 typically requires less computation than the first embodiment, and therefore generally requires less computation time or lower computational power. In contrast, the first embodiment of method step 200 typically achieves faster cooling of the rolled piece 15 than the second embodiment, because the iterations of sub-steps 207 to 209 enable the setting and minimum values ​​of the coolant flow for the cooling devices 21, 22, and 23. A more precise fit.

[0093] The above-described embodiment of the method according to the invention involves progressively performing method steps 200 and 300 on rolling sections of the rolled piece 15, which successively pass through the working regions 31, 32, and 33 of the cooling devices 21, 22, and 23. In this embodiment of the method according to the invention, for example, for each rolling section, according to... Figure 3 or Figure 4 One of the described embodiments is used to perform method step 200. However, alternatively, it is also possible to modify the design of the method according to the invention. Figure 3 and Figure 4 The described embodiments.

[0094] Appendix Figure 5 ( Figure 5 ) shows Figure 3 This is a modification of the embodiment shown. In this modification, a second running index is used to number the rolling sections. In the second sub-step 202, as in Figure 3 The initial total amount of coolant 35 received as shown in the embodiment. Additionally, in the second sub-step 202, the second run index is given. Assign a value of 1 as the initial value. For the second running index. The corresponding current value, that is, for the assigned rolling section, such as Figure 3 Sub-steps 203 to 214 are implemented as shown in the embodiment illustrated.

[0095] The average temperature calculated in sub-step 213 With sufficient precision and the target average temperature of the rolled section after the cooling process. Under the same conditions, however, a second running index is now added in sub-step 217 after sub-step 214. The value of the average temperature calculated in sub-step 213. The target average temperature of the rolled section after the cooling process was not achieved with sufficient precision. Under consistent conditions, such as in Figure 3 In the embodiment shown, the total amount of coolant is changed in sub-step 215. The value, and subsequently, in substep 217, the second run index is added. The value is accepted here, having a second running index. The smaller value of the rolled section after the cooling process still does not reach the target average temperature with sufficient accuracy. Consistent average temperature.

[0096] After substep 217, for the second run index The new value is used to implement sub-step 203, that is, to change the total amount of coolant in a feasible manner. Let's begin simulating the cooling process of the subsequent rolling section. Figure 5 In the embodiment shown, the cooling section process is simulated exactly once for each rolling section, and the total amount of coolant adapted in sub-step 215 is in a feasible manner. The simulation is passed to the cooling section process for the corresponding subsequent rolling section. In this way, the second method step 200 implemented for the rolling section is associated with the second method step 200 implemented for subsequent rolling sections. After each implementation of the second method step 200, a second operation index of the coolant flow is stored for each cooling device 21, 22, 23. The corresponding value, the set value determined during this implementation of method step 200. For the second running index The value stored is the set value. It will not be targeted at the second running index. The set value determined by other values cover.

[0097] If the second running index If the final value is reached, the repeated implementation of step 200 of the second method ends. For example, after each implementation of step 200 of the second method, check the second running index. If the final value has been reached, and if not, then only sub-step 217 is performed. Otherwise, the repetition of step 200 in the second method ends. This is in Figure 5 The text is not shown for clarity reasons.

[0098] In addition, Figure 5 Strictly speaking, it has an index. or The parameter must have an additional index. As long as these parameters are for the second running index Different values ​​can be distinguished from each other. For example, the set value must then be used... Instead of using To indicate. In Figure 5 This point has also been omitted for clarity.

[0099] The third method step 300 is also executed independently for each rolling section and can be performed without depending on other rolling sections. Here, the value of the second run index is... The third method step 300 has been executed, in which, by means of cooling devices 21, 22, 23, the value of the second operating index is obtained. In the cooling section of the rolled section, this value will be targeted. The coolant flow determined separately The output is sent to the rolling section, and for sections with... The value of the second running index To execute the second method step 200. For this purpose, in method step 300, for each cooling device 21, 22, 23, a value is obtained based on the transport speed or the transport speed trend over time. When is the rolled section located within the functional areas 31, 32, and 33 of the cooling devices 21, 22, and 23? The cooling devices 21, 22, and 23 are then configured such that, considering the associated delay time, if a value is present... If the rolled section is located within the functional areas 31, 32, and 33 of the cooling devices 21, 22, and 23, then the cooling device will precisely output a value corresponding to that value. The determined coolant flow .

[0100] Appendix Figure 6 ( Figure 6 The second method step 200 is shown in the diagram. Figure 4 The embodiments shown are related to Figure 5 Similar modification schemes.

[0101] The embodiments described above regarding the method according to the invention can also be performed when the rolled piece is transported multiple times through the cooling section 19. The finishing mill train 9 can, for example, have a reversible stand through which the rolled piece 15 is guided multiple times in alternating directions. Thus, the rolled piece 15 can also be transported multiple times through the cooling section 19 in alternating directions. In this case, method steps 200 and 300 are performed for each cooling section process. For example, in this case, a second measuring point is provided behind the cooling section 19, that is, between the intermediate roller table 7 and the finishing mill train 9, and the surface temperature of the surface portion of the rolled piece surface 29 belonging to the rolled piece section is detected at this second measuring point before the rolled piece section begins to pass through the cooling section 19 from the second measuring point. For the simulation of this cooling section process of the rolled piece section, the original initial enthalpy distribution and / or the original initial temperature distribution are determined based on the surface temperature of the surface portion of the rolled piece surface 29 belonging to the rolled piece section detected at the second measuring point.

[0102] Furthermore, the intermediate roller table 7 can have multiple cooling sections 19, or the cooling sections 19 can have multiple sub-cooling sections, for which the method according to the invention is implemented individually (each sub-cooling section is thus understood as a cooling section in the sense of the invention). If, for example, an intermediate measuring point for detecting the surface temperature of the rolled piece 15 is arranged in the intermediate roller table 7, the method according to the invention can be implemented individually for the first sub-cooling section or the cooling section arranged between the first measuring point 39 and the intermediate measuring point, and for the second sub-cooling section or the cooling section arranged between the intermediate measuring point and the finishing mill line 9. For the second sub-cooling section or cooling section, the original initial temperature distribution and / or the original initial enthalpy distribution are then determined based on the surface temperature of the rolled piece 15 detected at the intermediate measuring point. If multiple intermediate measuring points for detecting the surface temperature of the rolled piece 15 are arranged in the intermediate roller table 7, the corresponding cases can be adopted.

[0103] Appendix Figure 7 ( Figure 7 The temperature in the rolling section is shown as an example. , and Before and during the cooling section process of cooling section 19, over time The changing temperature trend obtained when using the method according to the present invention. Here, This indicates the core temperature in the middle section between the upper and lower surfaces of the rolled section 15. This indicates the surface temperature at point 29 on the surface of the rolled piece 15. The average temperature of the rolled section is represented by equation (8).

[0104] Approximately 3 seconds after the zero point, the rolled section enters the cooling section 19. Due to the cooling effect of cooling devices 21, 22, and 23 at the beginning of cooling section 19, the surface temperature... The temperature rapidly decreases from approximately 1070°C when entering the cooling section 19 from the rolling zone to a minimum. The minimum value in this case is approximately 800°C, and it has been determined by the surface temperature approximately 5.5 seconds after the zero point. This minimum value is reached. In another phase of the cooling process within the rolling section, the surface temperature of that rolling section... The cooling devices 21, 22, and 23 of the cooled section 19 are maintained at a relatively constant minimum value according to the present invention. The heat is released from the cooling section 19 approximately 7.7 seconds after time zero. After this point, the surface temperature increases as heat is directed from the interior of the rolling section to the surface 29 of the rolled piece. The core temperature in the rolling section has increased due to the current lack of cooling. The temperature is maintained relatively constant at approximately 1100°C during the cooling process. This is the average temperature of the rolling section. During the cooling process, the temperature drops from approximately 1090°C to approximately 1020°C.

[0105] Although the present invention has been illustrated and described in detail through preferred embodiments, the present invention is not limited to the disclosed embodiments, and those skilled in the art can derive other variations therefrom without departing from the scope of protection of the present invention.

[0106] List of reference numerals in the attached diagram: 1. Hot rolling equipment 3 Heating Furnace 5 Pre-rolling mill trains 7. Intermediate roller conveyor 9 Finishing Mill Train 11. Exit Cooling Area 13. Winding Machine Area 15 Rolled parts 17 Pre-rolling mill stands 19 Cooling Section 21, 22, 23 Cooling devices 25 transport rollers 27 Control Unit 29. Surface of rolled piece Areas of Effect (31, 32, 33) 35 Coolant 37 Measuring device 39 Measurement Location 41 Finishing mill rolling stands 43 Cooling device for finishing mill train 45 Finishing mill coolant 47, 49 Outlet cooling devices 51. Outlet coolant 53 Rolled Parts Coiling Machine 100, 200, 300 Methods and Steps Sub-steps 201 to 217 time Core temperature Surface temperature Average temperature.

Claims

1. A method for cooling a rolled piece (15) in a cooling section (19) preceding a finishing mill line (9) arranged in a hot rolling mill (1), The rolled piece (15) is transported along the cooling section once at a predetermined transport speed or multiple times in alternating directions at predetermined transport speeds, and the cooling section has cooling devices (21, 22, 23) with working areas (31, 32, 33) or multiple cooling devices (21, 22, 23) arranged sequentially along the cooling section with working areas (31, 32, 33). in, The working areas (31, 32, 33) of the adjacent cooling devices (21, 22, 23) are closely adjacent to each other, and each cooling device (21, 22, 23) can output a coolant flow (35) of coolant (35) to the surface (29) of the rolled piece (15) within its working area (31, 32, 33). This coolant flow can be set between zero and a maximum value specific to the cooling device (21, 22, 23), wherein, - During the transport of the rolled piece (15) through the cooling section (19), the surface temperature of the rolled piece surface (29) is received. The minimum value of ) - In order to comply with the minimum value, each cooling device (21, 22, 23) is assigned a set value for the coolant flow for each cooling section process through the cooling section (19), and - By means of each cooling device (21, 22, 23), a coolant flow is output to the surface (29) of the rolled piece in each cooling section process, and the coolant flow is set to the set value of the corresponding cooling device (21, 22, 23) for the cooling section process. - Wherein, in order to determine the set value for the cooling section process, the cooling section process of passing through the cooling section (19) at a predetermined transport speed is simulated at least once for the rolling section of the rolling piece (15), wherein, in each simulated cooling section process, each cooling device (21, 22, 23) is targeted step by step: -- No later than immediately before the rolled section enters the operating area (31, 32, 33) of the cooling device (21, 22, 23), a predetermined value for the coolant flow to be output by the cooling device (21, 22, 23) is received or determined. -- Based on the initial enthalpy distribution and / or initial temperature distribution of the rolled piece section when it enters the working area (31, 32, 33) of the cooling device (21, 22, 23), calculate the enthalpy distribution and / or temperature distribution of the rolled piece section when it exits from the working area (31, 32, 33) of the cooling device (21, 22, 23) according to the physical model. -- The setpoint is determined such that the setpoint will be maximized under auxiliary conditions by the coolant flow to be output from the cooling devices (21, 22, 23) onto the surface (29) of the rolled piece, so that the setpoint does not exceed the predetermined value, and the surface temperature of the rolled piece surface (29) at the output from the operating area (31, 32, 33) of the cooling devices (21, 22, 23), derived from the initial enthalpy distribution and / or initial temperature distribution, or derived from the calculated enthalpy distribution and / or calculated temperature distribution of the rolled piece section, is not lower than the minimum value. -- Wherein, for each pair of action zones (31, 32, 33) that pass adjacently to each other in the cooling section process, the enthalpy distribution and / or the calculated temperature distribution for the first action zone (31, 32, 33) at the time of output from the first action zone (31, 32, 33) will be allocated to the other action zones (31, 32, 33) as the initial enthalpy distribution and / or initial temperature distribution when entering the other action zones (31, 32, 33), and -- Wherein, for the first cooling device (21, 22, 23) through which the rolled section passes in the cooling section process, the original initial enthalpy distribution and / or the original initial temperature distribution are received. In each simulated cooling section of the rolling mill, at least one cooling device (21, 22, 23) is assigned according to... The set value, where, This refers to a predetermined value for the coolant flow to be output by the cooling devices (21, 22, 23). It is the surface temperature of the rolled piece surface (29) when it enters the effective area (31, 32, 33) of the cooling device (21, 22, 23), derived from the initial enthalpy distribution and / or initial temperature distribution. It refers to the surface temperature of the surface (29) of the rolled piece. The minimum value of ) It is a pre-defined backup temperature difference, and It is the following function: This function is for Zero, targeting It is 1, and in the interval It increases strictly in a monotonically increasing manner.

2. The method according to claim 1, wherein, In each simulated cooling section process, the setpoint for at least one cooling device (21, 22, 23) is determined by the following method: First, for a predetermined value of the coolant flow for the cooling device (21, 22, 23), the surface temperature of the rolled surface (29) when output from the working area (31, 32, 33) of the cooling device (21, 22, 23) is calculated. If the surface temperature calculated for the predetermined value is not lower than the minimum value, the setpoint is made equal to the predetermined value. Otherwise, the surface temperature when output from the working area (31, 32, 33) is iteratively calculated for at least one coolant flow that is less than the predetermined value in order to determine the following setpoint for the coolant flow: for this setpoint, the surface temperature calculated when output from the working area (31, 32, 33) is consistent with the minimum value with sufficient accuracy.

3. The method according to claim 1 or 2, wherein, For each cooling device (21, 22, 23), the maximum value of the coolant flow received in each simulated cooling section process is used as the predefined value for the coolant flow.

4. The method according to claim 1 or 2, wherein, For the simulation of the cooling section process of the rolled section, the maximum total amount of coolant (35) that can be output to the surface portion of the rolled section of the rolled surface (29) during the cooling section process is determined, and a predetermined value of the coolant flow for the simulated cooling section process is determined based on the total amount of coolant and the transport speed given in advance for the cooling section process.

5. The method according to claim 4, wherein, The target average temperature of the rolled piece (15) is received after the cooling section process. In each simulation of the cooling section process of the rolled piece section, the average temperature of the rolled piece section at the end of the cooling section process is calculated. If the calculated average temperature is not accurate enough to match the target average temperature, the total amount of coolant is changed for subsequent simulations of the cooling section process of the rolled piece section so that the calculated average temperature matches the target average temperature.

6. The method according to claim 4, wherein, In the simulation of the cooling section process of the rolled section, a coolant residual amount is allocated to each cooling device (21, 22, 23). The total coolant amount is allocated to the first cooling device (21, 22, 23) of the cooling section process as the coolant residual amount. Furthermore, each additional cooling device (21, 22, 23) is allocated the coolant residual amount of the previous cooling device (21, 22, 23) of the cooling section process minus the following cooling dose as the coolant residual amount: this cooling dose is output by the previous cooling device (21, 22, 23) to the surface portion of the rolled section surface (29) belonging to the rolled section according to the set value of the coolant flow obtained for that cooling device, and according to... To determine the predetermined value of the coolant flow rate of the cooling devices (21, 22, 23), wherein, It is the maximum value of the coolant flow of the cooling devices (21, 22, 23). It refers to the amount of coolant residue belonging to the cooling devices (21, 22, 23), and It is the maximum cooling dose that can be output to the surface portion of the rolled section of the rolled surface (29) by the cooling device (21, 22, 23) during the cooling section process.

7. The method according to claim 4, wherein, If, in the simulation of the cooling section process of the rolling section, a set value less than the predetermined value received by the cooling devices (21, 22, 23) is determined for the cooling devices (21, 22, 23), and if at least one subsequent cooling device (21, 22, 23) arrives later in the cooling section process, and the predetermined value received by the subsequent cooling device is less than the maximum value of the coolant flow of the cooling device (21, 22, 23), then the predetermined value is increased for at least one such subsequent cooling device (21, 22, 23) so that the total amount of cooling to be output to the surface portion of the rolling section belonging to the rolling section in the cooling section process is matched with the total amount of coolant determined for the cooling section process.

8. The method according to claim 1 or 2, wherein, In order to calculate the enthalpy and / or temperature distribution in the rolling section when output from the working area (31, 32, 33) of the cooling device (21, 22, 23), the one-dimensional heat conduction equation describing the enthalpy and / or temperature distribution along the thickness direction of the rolling section is solved in the simulation of the cooling section process of the rolling section.

9. The method according to claim 8, wherein, To solve the heat conduction equation, the following boundary conditions are considered, which parameterize: the cooling of the rolling section due to thermal radiation, the coolant output to the surface (29) of the rolling section, the heat discharged from the rolling section to the surrounding air, and the heat discharged from the rolling section to the transport rolls that transport the rolling section (15).

10. The method according to claim 1 or 2, wherein, At at least one measuring location (39) through which the rolled section passes before the cooling section process, the surface temperature of the surface portion of the rolled surface (29) belonging to the rolled section is measured. ), and based on at least one measured surface temperature ( To determine the original initial enthalpy distribution and / or the original initial temperature distribution for the simulation of the cooling section process for the rolled section.

11. The method according to claim 1 or 2, wherein the method is performed on the upper surface (29) or the lower surface (29) of the rolled piece (15), or separately on the upper surface (29) and the lower surface (29).

12. A cooling section (19) for cooling a rolled piece (15) before the finishing mill (9) of a hot rolling mill (1), the cooling section (19) comprising: - A cooling device (21, 22, 23) or multiple cooling devices (21, 22, 23) arranged sequentially along the cooling section (19) can output coolant (35) to the surface (29) of the rolled piece (15), the coolant flow being set between zero and a maximum value specific to the cooling device (21, 22, 23). - Multiple transport rollers (25) configured to transport the rolled piece (15) along the cooling section path through the cooling section (19), and - Control unit (27), which is configured to operate the cooling section (19) in accordance with any one of claims 1 to 11.

13. The cooling section (19) according to claim 12, having a plurality of cooling devices (21, 22, 23) arranged along the travel of the cooling section corresponding to the maximum value of the coolant flow that it can output, such that the maximum value decreases monotonically toward the finishing mill line (9).

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