Hot rolling method, hot rolling apparatus, and program

Abstract

To provide a hot rolling method simpler than a method not performing descaling and enabling reduction of rejected materials caused by scaling.SOLUTION: A hot rolling method includes: acquiring design conditions in hot rolling a steel plate; setting a target finishing temperature T0 of the steel plate, that is associated with the acquired design conditions; updating a maximum load Pmax in the hot rolling on the basis of the set target finishing temperature T0; and setting, on the basis of the updated maximum load Pmax, a new second rolling schedule with an increased pass number compared to an existing first rolling schedule having been implemented before the target finishing temperature T0 is set.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This disclosure relates to a hot rolling method, a hot rolling apparatus, and a program. [Background technology]

[0002] Traditionally, steel plates, such as thick steel plates, have been manufactured, for example, by reverse rolling in a hot rolling mill. A descaling device attached to the hot rolling mill is used after each reverse rolling cycle to cool the steel plate by spraying it with cooling water, thereby removing scale. The rolling method and rolling time of the steel plate are scheduled in the hot rolling mill. The scheduling was set with efficiency as the top priority. For example, after the maximum load was calculated in the hot rolling mill, the scheduling was set to the minimum number of passes required for the steel plate's finishing temperature to approximate the planned finishing temperature instructed by the higher-level computer.

[0003] However, prioritizing efficiency by setting a predetermined finishing temperature resulted in high steel plate temperatures, leading to scale formation after rolling completion and a high percentage of rejected materials. For example, when the predetermined finishing temperature exceeded 950°C, many materials were rejected due to scale. In the conventional technology described in Patent Document 1, descaling was performed by spraying cooling water multiple times during hot rolling for a longer duration than usual, up to 30 seconds. On the other hand, with special materials, descaling can cause cracks in the steel plate, making it impossible to spray cooling water during descaling, resulting in scale formation and ultimately rejection of the material. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 59-153513 [Overview of the project] [Problems that the invention aims to solve]

[0005] Conventional technology had the following problems:

[0006] For example, while increasing the descaling time makes scale removal more effective, only a maximum of 30 seconds was provided as a metric, and the indicator was not clearly defined. As a result, determining the metric relied on user experience and intuition.

[0007] For example, there are special materials that crack when descaling is performed, making descaling difficult in some cases. Even in such cases, there was a certain degree of demand to keep the finishing temperature of the steel plate low.

[0008] For example, the planned finishing temperature is set by a higher-level computer for the hot rolling mill. However, the actual design conditions for hot rolling of steel plates are determined by the hot rolling mill itself. Therefore, it was difficult to manage the planned finishing temperature based on the detailed design conditions using a higher-level computer.

[0009] This disclosure has been made in view of the above-mentioned problems, and aims to provide a hot rolling method, a hot rolling apparatus, and a program that can reduce the amount of unacceptable material due to scaling in a simpler way that does not involve descaling. [Means for solving the problem]

[0010] (1) A hot rolling method according to one embodiment of the present disclosure is: To obtain design conditions for hot rolling of steel plates, Setting the target finishing temperature of the steel plate associated with the acquired design conditions, The maximum load in the hot rolling process is updated based on the set target finishing temperature, A new second rolling schedule, which has an increased number of passes compared to the existing first rolling schedule that was performed before the target finishing temperature was set, is set based on the updated maximum load. Includes.

[0011] (2) As one embodiment of the present disclosure, in (1), The process further includes calculating a first variation parameter for the number of passes based on the finishing temperature of the steel sheet in the final pass in the first rolling schedule, the temperature of the steel sheet in the pass immediately preceding the final pass, and the target finishing temperature. Updating the maximum load may include updating the maximum load based on the first variation parameter.

[0012] (3) In one embodiment of the present disclosure, in (1) or (2), The process may further include calculating a second variation parameter for the number of passes based on the finished temperature of the steel plate in the final pass of the second rolling schedule, the total number of passes, and the target finished temperature, which are calculated based on the updated maximum load.

[0013] (4) As one embodiment of the present disclosure, in (3), If it is determined that the second variation parameter is not within a predetermined numerical range, the process may be repeated by updating the maximum load.

[0014] (5) As one embodiment of the present disclosure, in (4), If, during the update of the maximum load, it is determined that the maximum load has not reached the lower limit, the process may be repeated, starting with updating the maximum load.

[0015] (6) In one embodiment of the present disclosure, in any of (1) to (5), Setting the second rolling schedule may include selecting from among a plurality of the second rolling schedules calculated by repeating the process the second rolling schedule in which the finished temperature of the steel sheet most closely approximates the target finished temperature.

[0016] (7) A hot rolling apparatus according to one embodiment of the present disclosure is: A hot rolling apparatus equipped with a control unit, The control unit, Obtain the design conditions for hot rolling of steel plates, Set the target finishing temperature of the steel plate, which is associated with the acquired design conditions. Based on the set target finishing temperature, the maximum load in the hot rolling process is updated. A new second rolling schedule is set based on the updated maximum load, with an increased number of passes compared to the existing first rolling schedule that was in operation before the target finishing temperature was set.

[0017] (8) A program according to one embodiment of the present disclosure is In the hot rolling mill, To obtain design conditions for hot rolling of steel plates, Setting the target finishing temperature of the steel plate associated with the acquired design conditions, The maximum load in the hot rolling process is updated based on the set target finishing temperature, A new second rolling schedule, which has an increased number of passes compared to the existing first rolling schedule that was performed before the target finishing temperature was set, is set based on the updated maximum load. Perform an action that includes this. [Effects of the Invention]

[0018] According to a hot rolling method, hot rolling apparatus, and program according to one embodiment of the present disclosure, it is possible to reduce the amount of unacceptable material due to scaling in a simpler way that does not involve descaling. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram showing an example of the configuration of a hot rolling system having a hot rolling apparatus according to one embodiment of the present disclosure. [Figure 2] This flowchart shows an example of the operations performed by the hot rolling mill shown in Figure 1. [Figure 3] This is a table diagram showing an example of a table used in steps S102 and S103 of Figure 2. [Figure 4] Figure 1 is the first graph illustrating an example of the process performed by the hot rolling mill shown in Figure 1. [Figure 5] Figure 1 is a second graph illustrating an example of the process performed by the hot rolling mill. [Figure 6] This is the third graph illustrating an example of the process performed by the hot rolling mill shown in Figure 1. [Figure 7] This is the fourth graph illustrating an example of the process performed by the hot rolling mill shown in Figure 1. [Figure 8] This is the fifth graph illustrating an example of the process performed by the hot rolling mill shown in Figure 1. [Figure 9] This is the sixth graph illustrating an example of the process performed by the hot rolling mill shown in Figure 1. [Modes for carrying out the invention]

[0020] In the following, one embodiment of this disclosure will be mainly described with reference to the attached drawings.

[0021] Figure 1 is a schematic diagram showing an example of the configuration of a hot rolling system 1 having a hot rolling mill 10 according to one embodiment of the present disclosure. Referring to Figure 1, an example of the configuration and operation of the hot rolling system 1 having a hot rolling mill 10 according to one embodiment of the present disclosure will be mainly described.

[0022] The hot rolling system 1 performs hot rolling on steel plates such as thick steel plates. The hot rolling system 1 comprises a hot rolling apparatus 10, a host computer 20, and a rolling mill 30. In the hot rolling system 1, the hot rolling apparatus 10 and the host computer 20 are connected to each other in a way that allows them to communicate with one another. The hot rolling apparatus 10 and the rolling mill 30 are also connected to each other in a way that allows them to communicate with one another.

[0023] The hot rolling mill 10 includes any device for controlling the hot rolling of a steel sheet in the hot rolling system 1. The hot rolling mill 10 sets a rolling schedule consisting of various passes and controls the rolling mill 30 based on the rolling schedule. In this disclosure, “rolling schedule” includes, for example, a plot of load values ​​set for the thickness obtained at a predetermined timing during hot rolling, with the horizontal axis being the thickness of the steel sheet and the vertical axis being the load applied to the steel sheet during hot rolling, plotted sequentially in the direction in which the thickness decreases. “Pass” includes, for example, each point plotted in a graph showing the dependence of the load on the thickness as a rolling schedule. The rolling schedule is, for example, one in which passes are set for at least one of the adjustment phase, widthening phase, and finishing phase in hot rolling.

[0024] The hot rolling mill 10 sets a new second rolling schedule with an increased number of passes compared to the existing first rolling schedule, based on the updated maximum load described later. The hot rolling mill 10 increases the number of passes for the second rolling schedule, which includes at least one of the adjustment phase, widthening phase, and finishing phase. In the following example, the hot rolling mill 10 increases the number of passes for the second rolling schedule, which includes the finishing phase. The hot rolling mill 10 includes a communication unit 11, a storage unit 12, an input unit 13, an output unit 14, and a control unit 15.

[0025] The communication unit 11 includes one or more communication interfaces connected to a network. These communication interfaces support, for example, mobile communication standards such as 4G (4th Generation) and 5G (5th Generation), wired LAN (Local Area Network) standards, or wireless LAN standards, but are not limited to these and may support any communication standard. For example, the communication interface may also support short-range wireless communication standards. In one embodiment, the hot rolling mill 10 is communicably connected to a host computer 20 and a rolling mill 30 via the communication unit 11. Various types of information are transmitted and received between the host computer 20, the rolling mill 30, and the communication unit 11.

[0026] The storage unit 12 includes storage modules such as an HDD (Hard Disk Drive), SSD (Solid State Drive), EEPROM (Electrically Erasable Programmable Read-Only Memory), ROM (Read-Only Memory), and RAM (Random Access Memory). The storage unit 12 stores information necessary to realize the operation of the hot rolling mill 10. The storage unit 12 stores information obtained through the operation of the hot rolling mill 10. For example, the storage unit 12 stores system programs, application programs, and various data obtained by any means such as communication.

[0027] The storage unit 12 may function as a main memory module, an auxiliary memory module, or a cache memory. The storage unit 12 is not limited to one built into the hot rolling mill 10, and may also include an external storage module connected by a digital input / output port such as USB (Universal Serial Bus).

[0028] The input unit 13 includes one or more input interfaces that detect user input and acquire input information based on user operations. These input interfaces include physical keys, capacitive keys, a touchscreen integrated with the display of the output unit 14, an imaging module such as a camera, and a microphone that accepts voice input.

[0029] The output unit 14 includes one or more output interfaces that output information to notify the user. These output interfaces include a display that outputs information as an image, a speaker that outputs information as sound, and a vibrator that outputs information as vibration. The display includes LCD (Liquid Crystal Display) and organic EL (Electro Luminescence) displays.

[0030] The control unit 15 includes one or more processors. In this disclosure, “processor” is a general-purpose processor or a dedicated processor specialized for a particular process, but is not limited to these. The control unit 15 includes, for example, a CPU (Central Processing Unit). The control unit 15 is communicatively connected to each component constituting the hot rolling mill 10 and controls the operation of the entire hot rolling mill 10.

[0031] The higher-level computer 20 includes general-purpose electronic devices such as PCs (Personal Computers). The higher-level computer 20 is communicatively connected to the hot rolling mill 10 and transmits a predetermined target finishing temperature to the hot rolling mill 10, thereby instructing the hot rolling mill 10 to finish the hot rolling of the steel plate at the said target finishing temperature. The higher-level computer 20 is not limited to these and may be one or multiple server devices that can communicate with each other, or other electronic devices dedicated to the hot rolling system 1. In addition, the higher-level computer 20 may also include general-purpose electronic devices other than PCs, such as tablet PCs, smartphones, and wearable devices such as smartwatches.

[0032] The rolling mill 30 includes any machine that performs hot rolling on a steel sheet. In hot rolling, the rolling mill 30 performs at least one of the adjustment phase, the widthening phase, and the finishing phase. In one embodiment of the hot rolling system 1, for example, the rolling mill 30 includes a finishing rolling mill that performs the finishing phase. The rolling mill 30 performs hot rolling on a steel sheet with a load set for a predetermined thickness of the steel sheet during hot rolling, according to the rolling schedule set in the hot rolling apparatus 10.

[0033] Figure 2 is a flowchart illustrating an example of the operation performed by the hot rolling mill 10 shown in Figure 1. The flowchart in Figure 2 shows the overall flow of the hot rolling method performed using the hot rolling mill 10.

[0034] In step S101, the control unit 15 of the hot rolling mill 10 acquires the design conditions for hot rolling of the steel sheet. In this disclosure, "design conditions" include conditions such as the sheet thickness before and after hot rolling, the sheet width before and after hot rolling, the sheet length before and after hot rolling, and the type of steel. The control unit 15 acquires such design conditions as input information based on user input operations using the input unit 13, via the input unit 13. The user inputs the desired predetermined design conditions for hot rolling of the steel sheet to the hot rolling mill 10 using the input unit 13 whenever they wish.

[0035] In step S102, the control unit 15 of the hot rolling mill 10 determines, based on the design conditions acquired in step S101, whether the steel sheet to be hot-rolled under those design conditions is a target material. More specifically, the control unit 15 refers to a table stored in the storage unit 12 and determines whether the design conditions acquired in step S101 are included in that table. If the control unit 15 determines that it is a target material, it executes the process in step S103. If the control unit 15 determines that it is not a target material, it executes the process in step S113.

[0036] In step S103, the control unit 15 of the hot rolling mill 10 sets a target finish temperature for the steel sheet, which is associated with the design conditions acquired in step S101. More specifically, the control unit 15 refers to a table stored in the memory unit 12 and reads out the target finish temperature for the steel sheet associated with the design conditions acquired in step S101. In this disclosure, “target finish temperature” means, for example, the finish temperature of the steel sheet immediately after the completion of the finishing phase of hot rolling by the rolling mill 30, and includes a finish temperature set as a target by the user.

[0037] Figure 3 is a table diagram showing an example of a table used in steps S102 and S103 of Figure 2. As shown in Figure 3, the table includes, for each predetermined number, design conditions including plate thickness, plate width, plate length, and steel type, and the target finishing temperature, relating them to each other. In addition to this information, the value of the maximum load before updating and the lower limit of the range in which the maximum load can be changed are also related, which are related to the maximum load update process in step S106 described later. In this disclosure, the "lower limit" is shown, for example, as the ratio of the change between the maximum load before updating and the lower limit maximum load to the maximum load before updating. The ratio is, for example, a percentage with the whole set to 100. However, it is not limited to this, and the ratio may be with the whole set to 1. Alternatively, the lower limit may be shown, for example, as the absolute value of the lower limit maximum load itself.

[0038] The control unit 15 acquires the table in advance using the input unit 13 as input information based on user input operations using the input unit 13. The control unit 15 acquires the table in advance as a preprocessing step before executing the series of processes shown in the flowchart of Figure 2. Before the user has the hot rolling machine 10 execute the hot rolling method according to one embodiment, the user inputs the information necessary to construct the table into the hot rolling machine 10 using the input unit 13. The control unit 15 stores the table acquired by the input unit 13 in the storage unit 12 in advance.

[0039] In step S104, the control unit 15 of the hot rolling mill 10 determines whether the target finishing temperature set in step S103 is lower than the planned finishing temperature instructed by the host computer 20. The control unit 15 reads the planned finishing temperature, which is received from the host computer 20 (which is communicatively connected to the hot rolling mill 10) and stored in the storage unit 12, and executes the determination process in step S104. If the control unit 15 determines that the target finishing temperature is lower than the planned finishing temperature, it executes the process in step S105. If the control unit 15 determines that the target finishing temperature is equal to or greater than the planned finishing temperature, it executes the process in step S113.

[0040] In step S105, the control unit 15 of the hot rolling mill 10 refers to the existing first rolling schedule that was executed before the target finishing temperature was set in step S103. The control unit 15 refers to the first rolling schedule stored in the memory unit 12. Based on the referenced first rolling schedule, the control unit 15 obtains the finishing temperature of the steel sheet in the final pass and the temperature of the steel sheet in the pass immediately preceding the final pass. The control unit 15 may obtain the finishing temperature of the steel sheet in the final pass and the temperature of the steel sheet in the pass immediately preceding the final pass based on past performance values, or it may obtain them by estimating or predicting based on an arbitrary calculation model. Based on the finishing temperature of the steel sheet in the final pass, the temperature of the steel sheet in the pass immediately preceding the final pass in the first rolling schedule, and the target finishing temperature set in step S103, the control unit 15 calculates a first variation parameter for the number of passes.

[0041] For example, the control unit 15 calculates the first variation parameter in the following manner. First, the control unit 15 calculates the temperature of the steel plate in the pass immediately preceding the final pass as T f-1 The finishing temperature of the steel plate in the final pass is set to T 1f The temperature difference ΔT1 is calculated based on Equation 1. ΔT1=T f-1 -T 1f (Formula 1)

[0042] Next, the control unit 15 calculates the influence coefficient α1 based on Equation 2, with ΔP being the number of passes to be increased. ΔP is, for example, 1. The influence coefficient α1 is a parameter related to the temperature decrease per pass. α1 = ΔP / ΔT1 (Equation 2)

[0043] Next, the control unit 15 calculates the first variation parameter ΔP1 based on equation 3, with the target finishing temperature set in step S103 as T0. ΔP1=(T 1f -T0)×α1=ΔP×(T 1f -T0) / (T f-1 -T 1f ) (Formula 3)

[0044] In step S106, the control unit 15 of the hot rolling apparatus 10 updates the maximum load P in the hot rolling of the steel sheet based on the target finishing temperature T0 set in step S103. max For example, the control unit 15 updates the maximum load P based on the first variation amount parameter ΔP1 calculated in step S105. max In the present disclosure, the "maximum load P" is, for example, the upper limit value of the load that can be obtained for each pass in the rolling schedule, and includes the upper limit value determined based on the specifications of the rolling mill 30 and the like. max

[0045] For example, the control unit 15 updates the maximum load P in the following procedure. First, the control unit 15 obtains the total load P in the finishing phase according to the first rolling schedule. max Subsequently, the control unit 15 uses the number of passes N in the finishing phase according to the first rolling schedule, and calculates a new maximum load P' based on Equation 4. tot 1p P' = P / (N + ΔP1) (Equation 4) max P' max = P tot / (N 1p + ΔP1) (Equation 4)

[0046] Here, the average load in the finishing phase according to the first rolling schedule is P, and the lower limit value of the range in which the maximum load value included in the table shown in FIG. 3 can be changed is P as a percentage. At this time, when the condition (P - P) / P × 100 < P is satisfied, the control unit 15 calculates a new maximum load P' based on Equation 5. ave low ave - P max / P max × 100 < P low The condition is satisfied, and a new maximum load P' is calculated based on Equation 5. max P' max = P max × (1 + (P low / 100)) (Equation 5)

[0047] The control unit 15 determines that the maximum load P is lower than the lower limit value P. max low ​​​​​​​Based on this, the maximum load P is not lower than the absolute value of the lower limit of the maximum load, according to Equation 5. max Adjusts the control unit 15 (P ave -P max ) / P max ×100 <P low The condition is met when the maximum load P is reached. max When the absolute value of the maximum load that is the lower limit falls below the absolute value of the maximum load, the maximum load P' is calculated based on Equation 5. max Calculate.

[0048] Furthermore, the user can use the input unit 13 of the hot rolling mill 10 to input the load P of the final pass in the finishing phase. f The load P of the final pass can also be adjusted. For example, the user can directly change the value on the screen while visually observing the output unit 14 of the hot rolling mill 10. f Adjust the load P of the final pass in the finishing phase according to the first rolling schedule when the load accuracy is low and the distortion of the steel plate is large. f In response, a load is applied based on one's own experience.

[0049] The control unit 15 is in a case where such load adjustment by the user is involved, P ave <P f At that time, a new maximum load P' based on Equation 6. max Calculate. P' max =P f (Formula 6)

[0050] The control unit 15 controls P based on one of formulas 4 to 6 depending on each case. max =P' max By doing so, the maximum load P max Update. Maximum load P max The maximum load P' is originally determined in the table shown in Figure 3, which is stored in the memory unit 12 of the hot rolling mill 10, but is calculated using any of equations 4 to 6. max It will be reconfigured as such.

[0051] In step S107, the control unit 15 of the hot rolling mill 10 determines the maximum load P updated in step S106. max Based on this, the second rolling schedule is calculated. For example, in step S106, the control unit 15 calculates the maximum load P max Update the value so that it decreases, and the maximum load P max A second rolling schedule is calculated with an increased number of passes in accordance with the decrease in [amount]. As an example, the control unit 15 calculates the second rolling schedule for the finishing phase. The control unit 15 then executes the subsequent processes in the flowchart shown in Figure 2 mainly based on the second rolling schedule instead of the existing first rolling schedule.

[0052] In step S108, the control unit 15 of the hot rolling mill 10 determines the finishing temperature T of the steel sheet in the final pass of the second rolling schedule calculated in step S107. 2f and the total number of passes in the finishing phase N 2p The control unit 15 obtains the finishing temperature T of the steel plate in the final pass. 2f This is obtained by estimating or predicting based on an arbitrary calculation model. The control unit 15 determines the finishing temperature T of the steel sheet in the final pass in the second rolling schedule calculated in step S107. 2f , Total number of passes in the finishing phase N 2p Based on the target finishing temperature T0 set in step S103, the second variation parameter ΔP2 of the number of passes is calculated.

[0053] For example, the control unit 15 calculates the second variation parameter ΔP2 in the following manner. First, the control unit 15 calculates the finishing temperature T in the first rolling schedule that was set immediately before the second rolling schedule. 1f and the total number of passes in the finishing phase N 1p The data is read from the memory unit 12 or the like and obtained. The control unit 15 calculates the temperature difference ΔT2 based on equation 7. ΔT² = T 1f -T 2f (Formula 7)

[0054] Next, the control unit 15 calculates the number of increased paths (N 2p-N 1p The influence coefficient α2 is calculated based on Equation 8. α²=(N 2p -N 1p ) / ΔT2 (Equation 8)

[0055] Next, the control unit 15 calculates the second variation parameter ΔP2 based on equation 9. ΔP2=(T 2f -T0)×α2=(N 2p -N 1p )×(T 2f -T0) / (T 1f -T 2f ) (Formula 9)

[0056] In step S109, the control unit 15 of the hot rolling mill 10 determines whether the second variable parameter ΔP2 calculated in step S108 falls within a predetermined numerical range. In this disclosure, the "predetermined numerical range" includes, for example, a range greater than -1 and less than or equal to 0. That is, the control unit 15 determines whether -1 < ΔP2 ≤ 0.

[0057] If the control unit 15 determines that the second variation parameter ΔP2 is not within a predetermined numerical range, it executes the process in step S110. If the control unit 15 determines that the second variation parameter ΔP2 is within a predetermined numerical range, it executes the process in step S112. The control unit 15 reduces the number of passes, such as -1 < ΔP2 ≤ 0, but if the number of passes becomes less than 1, it terminates the calculation and executes the process in step S112, because further calculations would only result in repeated overshoots.

[0058] In step S110, the control unit 15 of the hot rolling mill 10 determines the maximum load P in step S106. max Maximum load P in the update max The control unit 15 determines whether the maximum load P has reached the lower limit. For example, when it is determined in step S109 that 0 < ΔP2, the control unit 15 determines whether the maximum load P max The control unit 15 determines whether the maximum load P has reached the lower limit. maxIf it is determined that the maximum load P has not reached the lower limit, the process in step S111 is executed. max When it is determined that the lower limit has been reached, the process in step S112 is executed. The control unit 15 increases the number of passes, such as 0 < ΔP2, to set the finishing temperature T 2f We want to reduce the maximum load P max When the lower limit is reached, the maximum load P max Since it is not possible to further reduce the number of passes and increase it, the calculation is terminated and the process in step S112 is executed.

[0059] In step S111, the control unit 15 of the hot rolling mill 10 determines whether the number of repetitions of the process has been reached. If the control unit 15 determines that the number of repetitions has not been reached, it repeats the process in step S106. That is, in step S109, the control unit 15 determines that the second variable amount parameter ΔP2 is not within a predetermined numerical range, and in step S110, it determines that the maximum load P max If it is determined that the lower limit has not been reached, then the maximum load P max The process is repeated again from step S106, which updates the value. The control unit 15 determines the maximum load P when 0 < ΔP2. max If the lower limit has not been reached, or if ΔP2 ≤ -1, there is still room for calculation regarding the increase or decrease in the number of passes, so a new calculation based on ΔP2 is performed.

[0060] If the control unit 15 repeats the process of step S106, it will retrieve the finishing temperature T in the first rolling schedule that was stored in the memory unit 12. 1f and the total number of passes in the finishing phase N 1p The finishing temperature T in the second rolling schedule calculated in the previous step S107 is then repeated. 2f and the total number of passes in the finishing phase N 2p These are updated accordingly. Furthermore, the control unit 15 repeatedly performs the same calculation process as described above, using the second variation parameter ΔP2 instead of the first variation parameter ΔP1.

[0061] For example, in step S106, the control unit 15 obtains the total load P of the finishing phase in the second rolling schedule calculated in the previous step S107. tot Subsequently, the control unit 15 obtains the total number N of passes of the finishing phase path according to the second rolling schedule. 2p The control unit 15 calculates a new maximum load P' based on Equation 10 similar to Equation 4, substituting the first variation parameter ΔP1 with the second variation parameter ΔP2. max The control unit 15 sets P max = P' max to further update the maximum load P. max P' max = P tot / (N 2p + ΔP2) (Equation 10)

[0062] For example, in step S108, the control unit 15 replaces the finishing temperature T and the total number N of passes of the finishing phase path in the first rolling schedule with the finishing temperature T and the total number N of passes of the finishing phase path in the second rolling schedule calculated in the previous step S107, and similarly executes the arithmetic processing from Equation 7 to Equation 9. 1f 1p 2f 2p

[0063] When the control unit 15 determines in step S111 that the number of repetitions has been reached, it executes the process of step S112. In step S112, the control unit 15 of the hot rolling apparatus 10 sets a new second rolling schedule with an increased number of passes compared to the existing first rolling schedule that was executed before the target finishing temperature T0 was set in step S103, based on the maximum load P updated in step S106. When there are multiple second rolling schedules calculated in step S108 due to the control unit 15 repeating the process via step S111, among the multiple second rolling schedules, the control unit 15 selects the second rolling schedule in which the finishing temperature T of the steel sheet is closest to the target finishing temperature T0. max 2f

[0064] In step S113, the control unit 15 of the hot rolling mill 10 sets the rolling schedule in a normal manner that does not use the hot rolling method according to one embodiment of the present disclosure, rather than setting a new rolling schedule by increasing the number of passes, such as the second rolling schedule based on the processing from step S105 to step S112.

[0065] Figure 4 is the first graph illustrating an example of the process performed by the hot rolling mill 10 in Figure 1. Figure 5 is the second graph illustrating an example of the process performed by the hot rolling mill 10 in Figure 1. Figure 6 is the third graph illustrating an example of the process performed by the hot rolling mill 10 in Figure 1. Figure 7 is the fourth graph illustrating an example of the process performed by the hot rolling mill 10 in Figure 1. Figure 8 is the fifth graph illustrating an example of the process performed by the hot rolling mill 10 in Figure 1. Figure 9 is the sixth graph illustrating an example of the process performed by the hot rolling mill 10 in Figure 1.

[0066] Figures 4 to 9 show the rolling schedule, including the second rolling schedule in the finishing phase, when the hot rolling method according to one embodiment is executed according to the flowchart shown in Figure 2, based on the "effective" solid line graph. As a comparison to the second rolling schedule, Figures 4 to 9 show the rolling schedule when set by the normal method, based on the "ineffective" dashed line graph. In each graph, the vertical axis represents the load applied to the steel sheet in each pass of the hot rolling schedule. The horizontal axis represents the thickness of the steel sheet obtained in each pass. The hot rolling apparatus 10 controls the rolling mill 30 so that each pass is passed from right to left, with the pass with the largest sheet thickness as the first pass and the pass with the smallest sheet thickness as the last pass, thereby performing hot rolling.

[0067] As shown in each graph, the maximum load P occurs mainly in the finishing phase of hot rolling, in the second rolling schedule. maxThe load is reduced, and the number of passes is increased compared to the rolling schedule set in the normal way. In the finishing phase, the average load for all passes of the second rolling schedule is smaller than that of the rolling schedule set in the normal way. As described above, the control unit 15 of the hot rolling mill 10 controls the maximum load P max We have successfully applied a second rolling schedule, which reduces the number of passes while increasing the number of passes, to the finishing phase of hot rolling.

[0068] The control unit 15 of the hot rolling mill 10 may, as necessary, display at least some of the data from the graph diagrams shown in Figures 4 to 9 via the output unit 14. For example, the control unit 15 may display the graph diagrams shown in Figures 4 to 9 as they are via the output unit 14, or it may display only one of the rolling schedules, including the second rolling schedule and the rolling schedule set by the normal method, via the output unit 14.

[0069] According to the hot rolling mill 10 of the above embodiment, it is possible to reduce the amount of unacceptable material due to scale in a simpler way than descaling. The hot rolling mill 10 has a new second rolling schedule that increases the number of passes compared to the existing first rolling schedule and has an updated maximum load P max The settings are determined based on this. As a result, the hot rolling mill 10 adjusts the finishing temperature T of the steel sheet according to the increase in the number of passes. 2f This reduces the amount of scale generated, thereby suppressing the formation of scale. As a result, the hot rolling mill 10 can reduce the amount of unacceptable material caused by scale.

[0070] The hot rolling mill 10 can reach the finishing temperature T of the steel sheet without descaling. 2f It is possible to lower the temperature. Therefore, the hot rolling mill 10 can also reduce the finishing temperature of the steel sheet T, even for special materials where descaling causes cracks in the steel sheet. 2f It is also possible to reduce the scale and suppress its occurrence.

[0071] The hot rolling mill 10 sets a new target finishing temperature T0 in place of the planned finishing temperature set by the higher-level computer 20. This allows the hot rolling mill 10 to comprehensively manage the target finishing temperature T0 as information, along with the actual design conditions for hot rolling of the steel plate.

[0072] While this disclosure has been described based on the drawings and embodiments, it should be noted that those skilled in the art can make various modifications and alterations based on this disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of this disclosure. For example, the functions included in each configuration or step can be rearranged or omitted in a logically consistent manner, and multiple configurations or steps can be combined into one or divided into two.

[0073] For example, it is also possible to configure a general-purpose electronic device such as a smartphone or computer to function as the hot rolling mill 10 according to the above-described embodiment. Specifically, a program describing the processing content that realizes each function of the hot rolling mill 10 according to the embodiment is stored in the memory of the electronic device, and the processor of the electronic device reads and executes the program. Therefore, this disclosure can also be realized as a program that can be executed by a processor.

[0074] Alternatively, the disclosure may also be realized as a non-temporary computer-readable medium storing a program executable by one or more processors for causing a hot rolling mill 10 or the like to perform various functions according to one embodiment. These should also be understood to be included within the scope of the disclosure.

[0075] For example, at least some of the processing operations performed in the hot rolling mill 10 in the embodiment described above may be performed in at least one of the host computer 20 and the rolling mill 30. For example, instead of the hot rolling mill 10, the host computer 20 or the rolling mill 30 itself may perform the series of processing operations related to the hot rolling mill 10 described above. At least some of the processing operations performed in the host computer 20 may be performed in the hot rolling mill 10. At least some of the processing operations performed in the rolling mill 30 may be performed in the hot rolling mill 10. [Explanation of Symbols]

[0076] 1. Hot rolling system 10 Hot rolling mill 11 Communications Department 12 Storage section 13 Input section 14 Output section 15 Control Unit 20 top calculator 30 Rolling mill N 1p , N 2p Total ΔP1 First variation parameter ΔP2 Second variation parameter P ave average load P f Load of the final pass P low Lower limit P max , P' max Maximum load P tot Total load ΔT1, ΔT2 temperature difference T0 Target finishing temperature T 1f , T 2f Finishing temperature α1, α2 influence coefficients

Claims

1. To obtain design conditions for hot rolling of steel plates, The target finishing temperature T of the steel plate associated with the acquired design conditions. ０ Setting and The finishing temperature T of the steel sheet in the final pass of the existing first rolling schedule that was performed before the aforementioned target finishing temperature was set. １ｆ , the temperature T of the steel plate in the pass immediately preceding the final pass. ｆ－１ , the number of passes to be increased in a new second rolling schedule, which has an increased number of passes compared to the first rolling schedule, ΔP, and the target finishing temperature T ０ Based on this, the first variation parameter ΔP of the number of passes is calculated using the following equation (1). １ To calculate, ΔP １ =ΔP×(T １ｆ -T ０ ) / (T ｆ－１ -T １ｆ ) ・・・ (1) The first variation parameter ΔP １ Based on this, the maximum load in the hot rolling process is updated, Setting the second rolling schedule based on the updated maximum load, including, Hot rolling method.

2. A hot rolling method according to claim 1, The total number of passes N in the first rolling schedule １ｐ , the finishing temperature T of the steel plate in the final pass of the second rolling schedule, calculated based on the updated maximum load. ２ｆ , Total number of passes N ２ｐ , and the target finishing temperature T ０ Based on this, the second variation parameter ΔP of the number of passes is calculated using the following equation (2). ２ Calculate ΔP ２ =(N ２ｐ -N １ｐ )×(T ２ｆ -T ０ ) / (T １ｆ -T ２ｆ ) ・・・ (2) Further including, Hot rolling method.

3. A hot rolling method according to claim 2, If it is determined that the second variable parameter is not within a predetermined numerical range, the process is repeated by updating the finishing temperature T1f of the steel plate and the total number of passes N1p, and updating the maximum load. Hot rolling method.

4. A hot rolling method according to claim 3, The determination further includes determining that the maximum load has not reached the lower limit and that the maximum load can be further reduced. Hot rolling method.

5. A hot rolling method according to claim 3, Setting the second rolling schedule includes selecting from among a plurality of the second rolling schedules calculated by repeating the above process the second rolling schedule in which the finished temperature of the steel sheet most closely approximates the target finished temperature. Hot rolling method.

6. A hot rolling apparatus equipped with a control unit, The control unit, Obtain the design conditions for hot rolling of steel plates, The target finishing temperature T of the steel plate associated with the acquired design conditions. ０ Set, The finishing temperature T of the steel sheet in the final pass of the existing first rolling schedule that was performed before the aforementioned target finishing temperature was set. １ｆ , the temperature T of the steel plate in the pass immediately preceding the final pass. ｆ－１ , the number of passes to be increased in a new second rolling schedule, which has an increased number of passes compared to the first rolling schedule, ΔP, and the target finishing temperature T ０ Based on this, the first variation parameter ΔP of the number of passes is calculated using the following equation (1). １ Calculate, ΔP １ =ΔP×(T １ｆ -T ０ ) / (T ｆ－１ -T １ｆ ) ・・・ (1) The first variation parameter ΔP １ Based on this, the maximum load in the hot rolling process was updated, The second rolling schedule is set based on the updated maximum load. Hot rolling mill.

7. In the hot rolling mill, To obtain design conditions for hot rolling of steel plates, The target finishing temperature T of the steel plate associated with the acquired design conditions. ０ Setting and The finishing temperature T of the steel sheet in the final pass of the existing first rolling schedule that was performed before the aforementioned target finishing temperature was set. １ｆ , the temperature T of the steel plate in the pass immediately preceding the final pass. ｆ－１ , the number of passes to be increased in a new second rolling schedule, which has an increased number of passes compared to the first rolling schedule, ΔP, and the target finishing temperature T ０ Based on this, the first variation parameter ΔP of the number of passes is calculated using the following equation (1). １ To calculate, ΔP １ =ΔP×(T １ｆ -T ０ ) / (T ｆ－１ -T １ｆ ) ・・・ (1) The first variation parameter ΔP １ Based on this, the maximum load in the hot rolling process is updated, Setting the second rolling schedule based on the updated maximum load, Perform an action that includes program.

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