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

[0002] Conventionally, steel plates such as thick steel plates are manufactured by, for example, reverse rolling in a hot rolling mill. A descaling device attached to the hot rolling mill is used for each reverse rolling to spray cooling water onto the steel plate to cool it and remove scale. The rolling method and rolling time of the steel plate are scheduled in the hot rolling mill. The scheduling is set with the highest priority on efficiency. For example, the scheduling is set to the minimum number of passes that makes the finishing temperature of the steel plate approximate the planned finishing temperature instructed by a higher-level computer after the maximum load is calculated in the hot rolling mill.

[0003] However, when the planned finishing temperature was set with priority given to efficiency, the steel plate temperature was high, and scale formed after the rolling was completed, resulting in a high rate of rejected products. For example, when the planned finishing temperature was 950°C or higher, many rejects due to scale occurred. In the conventional technology described in Patent Document 1, therefore, descaling was performed by spraying cooling water multiple times during hot rolling for a longer period than usual, up to 30 seconds, to remove the scale. On the other hand, for special materials, descaling can cause cracks in the steel plate, and it is not possible to spray cooling water during descaling, which ultimately results in scale formation and the resulting product being rejected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 59-153513 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional technology has the following problems.

[0006] For example, although the descaling time is increased to remove scale more effectively, the maximum descaling time is limited to 30 seconds, and the indicator is not clear. As a result, the indicator is determined by the user's experience and feeling.

[0007] For example, there are some special materials that can cause cracks in the steel plate when descaling is performed, making descaling difficult. Even in such cases, there is a certain demand to lower the finishing temperature of the steel plate.

[0008] For example, the planned finishing temperature is set by a host computer for a hot rolling mill. However, the actual design conditions for hot rolling of steel sheets are determined by the hot rolling mill. Therefore, it is difficult for the host computer to manage the planned finishing temperature based on the details of the design conditions.

[0009] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a hot rolling method, hot rolling apparatus, and program that can reduce rejects caused by scale using a simpler method that does not require descaling. [Means for solving the problem]

[0010] (1) A hot rolling method according to an embodiment of the present disclosure, Obtaining design conditions for hot rolling of steel plates; Setting a target finishing temperature of the steel plate, the target finishing temperature being associated with the acquired design conditions; Updating a maximum load in the hot rolling based on the set target finishing temperature; Setting a new second rolling schedule in which the number of passes is increased compared to the existing first rolling schedule that was executed before the target finishing temperature was set, based on the updated maximum load; Includes.

[0011] (2) As an embodiment of the present disclosure, in (1), The method further includes calculating a first variation parameter of the number of passes based on a finishing temperature of the steel sheet in a final pass in the first rolling schedule, a temperature of the steel sheet in a pass one pass before 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) As an embodiment of the present disclosure, in (1) or (2), The method may further include calculating a second variation parameter for the number of passes based on the finishing temperature of the steel plate in a final pass in the second rolling schedule calculated based on the updated maximum load, the total number of passes, and the target finishing temperature.

[0013] (4) As an 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 starting from updating the maximum load.

[0014] (5) As an embodiment of the present disclosure, in (4), If it is further determined in updating the maximum load that the maximum load has not reached a lower limit value, the process may be repeated again, beginning with updating the maximum load.

[0015] (6) As an embodiment of the present disclosure, in any one of (1) to (5), Setting the second rolling schedule may include selecting, from among a plurality of second rolling schedules calculated by repeating the process, the second rolling schedule in which the finishing temperature of the steel plate is closest to the target finishing temperature.

[0016] (7) A hot rolling apparatus according to an embodiment of the present disclosure, A hot rolling apparatus including a control unit, The control unit is Obtaining design conditions for hot rolling of steel plates, Setting a target finishing temperature of the steel plate, which is associated with the acquired design conditions; updating a maximum load in the hot rolling based on the set target finishing temperature; A new second rolling schedule having an increased number of passes compared to the existing first rolling schedule that was executed before the target finishing temperature was set is set based on the updated maximum load.

[0017] (8) A program according to an embodiment of the present disclosure, For hot rolling equipment, Obtaining design conditions for hot rolling of steel plates; Setting a target finishing temperature of the steel plate, the target finishing temperature being associated with the acquired design conditions; Updating a maximum load in the hot rolling based on the set target finishing temperature; Setting a new second rolling schedule in which the number of passes is increased compared to the existing first rolling schedule that was executed before the target finishing temperature was set, based on the updated maximum load; The method executes an operation including: Effect of the Invention

[0018] According to the hot rolling method, hot rolling apparatus, and program according to an embodiment of the present disclosure, it is possible to reduce rejects caused by scale using a simpler method that does not involve descaling. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing an example of a configuration of a hot rolling system having a hot rolling apparatus according to an embodiment of the present disclosure. [Diagram 2] 2 is a flowchart showing an example of an operation performed by the hot rolling apparatus of FIG. 1. [Diagram 3] FIG. 3 is a table diagram showing an example of a table used in steps S102 and S103 of FIG. 2. [Figure 4] FIG. 2 is a first graph for explaining an example of a process executed by the hot rolling apparatus of FIG. [Diagram 5] 1. FIG. 4 is a second graph diagram for explaining an example of the process executed by the hot rolling apparatus of FIG. [Figure 6] 1. FIG. 4 is a third graph diagram for explaining an example of the process executed by the hot rolling apparatus of FIG. [Figure 7] 1. FIG. 4 is a fourth graph diagram for explaining an example of a process executed by the hot rolling apparatus of FIG. [Figure 8] 1. FIG. 5 is a fifth graph diagram for explaining an example of a process executed by the hot rolling apparatus of FIG. [Figure 9] 1. FIG. 6 is a sixth graph for explaining an example of a process executed by the hot rolling apparatus of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An embodiment of the present disclosure will be mainly described below with reference to the accompanying drawings.

[0021] Fig. 1 is a schematic diagram showing an example of a configuration of a hot rolling system 1 having a hot rolling apparatus 10 according to an embodiment of the present disclosure. With reference to Fig. 1, an example of the configuration and operation of the hot rolling system 1 having the hot rolling apparatus 10 according to an 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 includes a hot rolling device 10, a host computer 20, and a rolling mill 30. In the hot rolling system 1, the hot rolling device 10 and the host computer 20 are connected to each other so that they can communicate with each other. The hot rolling device 10 and the rolling mill 30 are connected to each other so that they can communicate with each other.

[0023] The hot rolling apparatus 10 includes any device for controlling the hot rolling of the steel plate in the hot rolling system 1. The hot rolling apparatus 10 sets a rolling schedule consisting of various passes, and controls the rolling mill 30 based on the rolling schedule. In the present disclosure, the "rolling schedule" includes, for example, a plot of load values ​​set for a thickness obtained at a predetermined timing during hot rolling in a direction in which the thickness becomes thinner, when the horizontal axis is the thickness of the steel plate and the vertical axis is the load applied to the steel plate during hot rolling. The "pass" includes, for example, each point plotted in a graph showing the dependency of the load on the plate thickness as a rolling schedule. The rolling schedule is, for example, a pass set for at least one of the adjustment phase, the width making phase, and the finishing phase in hot rolling.

[0024] The hot rolling apparatus 10 sets a new second rolling schedule in which the number of passes is increased compared to the existing first rolling schedule, based on an updated maximum load described later. The hot rolling apparatus 10 increases the number of passes for the second rolling schedule including at least one of an adjustment phase, a width setting phase, and a finishing phase. In the following, as an example, the hot rolling apparatus 10 increases the number of passes for the second rolling schedule including a finishing phase. The hot rolling apparatus 10 has a communication unit 11, a memory 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 for connecting to a network. The communication interface corresponds to, for example, a mobile communication standard such as 4G (4th Generation) and 5G (5th Generation), a wired LAN (Local Area Network) standard, or a wireless LAN standard, but may correspond to any communication standard without being limited thereto. For example, the communication interface may correspond to a short-range wireless communication standard. In one embodiment, the hot rolling apparatus 10 is communicably connected to the host computer 20 and the rolling mill 30 via the communication unit 11. Various information is transmitted and received between the communication unit 11 and each of the host computer 20 and the rolling mill 30.

[0026] The storage unit 12 includes storage modules such as a hard disk drive (HDD), a solid state drive (SSD), an electrically erasable programmable read-only memory (EEPROM), a read-only memory (ROM), and a random access memory (RAM). The storage unit 12 stores information necessary to realize the operation of the hot rolling apparatus 10. The storage unit 12 stores information obtained by the operation of the hot rolling apparatus 10. For example, the storage unit 12 stores a system program, an application program, and various data acquired by any means such as communication.

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

[0028] The input unit 13 includes one or more input interfaces that detect user input and acquire input information based on the user's operation. The input interfaces include physical keys, capacitive keys, a touch screen that is 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. The 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 an LCD (Liquid Crystal Display) and an organic EL (Electro Luminescence) display.

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

[0031] The host computer 20 includes a general-purpose electronic device such as a PC (Personal Computer). The host computer 20 is communicably connected to the hot rolling apparatus 10, and transmits a predetermined planned finishing temperature to the hot rolling apparatus 10 to instruct the hot rolling apparatus 10 to finish the hot rolling of the steel plate at the planned finishing temperature. The host computer 20 is not limited to these, and may be one or a plurality of server devices capable of communicating with each other, or may be another electronic device dedicated to the hot rolling system 1. In addition, the host computer 20 may include a general-purpose electronic device other than a PC, such as a tablet PC, a smartphone, and a wearable device such as a smart watch.

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

[0033] Fig. 2 is a flowchart showing an example of the operation performed by the hot rolling apparatus 10 of Fig. 1. The flowchart of Fig. 2 shows an overall flow of processing in a hot rolling method performed using the hot rolling apparatus 10.

[0034] In step S101, the control unit 15 of the hot rolling apparatus 10 acquires design conditions for hot rolling of a steel plate. In the present disclosure, the "design conditions" include conditions such as plate thickness before and after hot rolling, plate width before and after hot rolling, plate length before and after hot rolling, and steel type. The control unit 15 acquires such design conditions by the input unit 13 as input information based on an input operation of a user using the input unit 13. The user inputs predetermined design conditions desired for hot rolling of a steel plate to the hot rolling apparatus 10 using the input unit 13 when desired by the user.

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

[0036] In step S103, the control unit 15 of the hot rolling apparatus 10 sets a target finishing temperature of the steel plate associated with the design conditions acquired in step S101. More specifically, the control unit 15 refers to a table stored in the storage unit 12 and reads out the target finishing temperature of the steel plate associated with the design conditions acquired in step S101. In the present disclosure, the "target finishing temperature" is, for example, the finishing temperature of the steel plate immediately after the finishing phase of hot rolling by the rolling mill 30 is completed, and includes a finishing temperature set as a target by a user.

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

[0038] The control unit 15 acquires the table in advance by the input unit 13 as input information based on an input operation by a user using the input unit 13. The control unit 15 acquires the table in advance as pre-processing for executing a series of processes shown in the flowchart of FIG. 2. Before causing the hot rolling apparatus 10 to execute a hot rolling method according to one embodiment, the user inputs information required to construct the table to the hot rolling apparatus 10 using the input unit 13. The control unit 15 stores the table acquired by the input unit 13 in the memory unit 12 in advance.

[0039] In step S104, the control unit 15 of the hot rolling apparatus 10 judges whether or not the target finishing temperature set in step S103 is lower than the planned finishing temperature instructed from the host computer 20. The control unit 15 reads the planned finishing temperature received from the host computer 20, which is communicatively connected to the hot rolling apparatus 10, and stored in advance in the memory unit 12, and executes the judgment process of step S104. If the control unit 15 judges that the target finishing temperature is lower than the planned finishing temperature, it executes the process of step S105. If the control unit 15 judges that the target finishing temperature is equal to or higher than the planned finishing temperature, it executes the process of step S113.

[0040] In step S105, the control unit 15 of the hot rolling apparatus 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. The control unit 15 acquires the finishing temperature of the steel plate in the final pass and the temperature of the steel plate in the pass one pass before the final pass based on the referenced first rolling schedule. The control unit 15 may acquire the finishing temperature of the steel plate in the final pass and the temperature of the steel plate in the pass one pass before the final pass based on past actual values, or may acquire them by estimating or predicting based on an arbitrary calculation model. The control unit 15 calculates a first variation amount parameter of the number of passes based on the finishing temperature of the steel plate in the final pass in the first rolling schedule, the temperature of the steel plate in the pass one pass before the final pass, and the target finishing temperature set in step S103.

[0041] For example, the control unit 15 calculates the first fluctuation amount parameter in the following manner. First, the control unit 15 calculates the temperature of the steel sheet in the pass one pass before the final pass as T f-1 The finishing temperature of the steel plate in the final pass is T 1f Then, calculate the temperature difference ΔT1 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 the formula 2, assuming that the number of paths to be increased is ΔP. ​​ΔP is, for example, 1. The influence coefficient α1 is a parameter related to the amount of temperature drop per path. α1=ΔP / ΔT1 (Equation 2)

[0043] Next, the control unit 15 calculates the first fluctuation amount parameter ΔP1 based on Equation 3, with the target finish temperature set in step S103 being 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 determines the maximum load P in the hot rolling of the steel plate 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 fluctuation amount parameter ΔP1 calculated in step S105. max In this disclosure, "maximum load P max " is, for example, the upper limit of the load that can be taken for each pass in the rolling schedule, and includes an upper limit determined based on the specifications of the rolling mill 30, etc.

[0045] For example, the control unit 15 calculates the maximum load P max First, the control unit 15 updates the total load P in the finishing phase according to the first rolling schedule. tot Next, the control unit 15 determines the number of passes of the finishing phase according to the first rolling schedule as N 1p Based on Equation 4, the new maximum load P' max Calculate. 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 ave Let P be the lower limit of the range in which the maximum load value can be changed, as a percentage, in the table shown in Figure 3. low At this time, the control unit 15 sets (P ave -P max ) / P max ×100 <P low When the condition is met, the new maximum load P' is calculated based on Eq. max Calculate. P' max =P max ×(1+(P low / 100)) (Formula 5)

[0047] The control unit 15 determines the maximum load P max is the lower limit P lowThe maximum load P based on Equation 5 is set so as not to fall below the absolute value of the maximum load, which is the lower limit based on max The control unit 15 adjusts (P ave -P max ) / P max ×100 <P low The condition is satisfied and the maximum load P max When the absolute value of the maximum load falls below the lower limit, the maximum load P' is calculated based on Equation 5. max Calculate.

[0048] In addition, the user may input the load P of the final pass of the finishing phase using the input unit 13 of the hot rolling mill 10. f The user may adjust the load P of the final pass by, for example, directly changing the value on the screen while visually checking the output unit 14 of the hot rolling mill 10. f For example, the user may 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 steel plate distortion is large. f A load is applied to the target object based on the person's own experience.

[0049] When such a load adjustment by the user is involved, the control unit 15 ave <P f Then, the new maximum load P' is calculated based on Eq. max Calculate. P' max =P f (Formula 6)

[0050] The control unit 15 calculates P based on any one of the formulas 4 to 6 according to each case. max =P' max By doing so, the maximum load P max Update the maximum load P max is originally determined in the table shown in FIG. 3 stored in the memory unit 12 of the hot rolling apparatus 10, but the maximum load P' calculated by any one of Equations 4 to 6 max It will be re-set as

[0051] In step S107, the control unit 15 of the hot rolling apparatus 10 calculates the maximum load P max For example, the control unit 15 calculates the second rolling schedule based on the maximum load P max is updated to decrease, and the maximum load P max A second rolling schedule is calculated in which the number of passes is increased in accordance with the decrease in the number of passes. As an example, the control unit 15 calculates the second rolling schedule for the finishing phase. The control unit 15 executes the subsequent processing of the flowchart shown in FIG. 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 apparatus 10 determines the finishing temperature T 2f and the total number of passes in the finishing phase, N 2p The control unit 15 acquires the finishing temperature T 2f The control unit 15 obtains the finishing temperature T of the steel sheet in the final pass in the second rolling schedule calculated in step S107 by estimating or predicting based on an arbitrary calculation model. 2f , the total number of passes in the finishing phase N 2p , and the target finishing temperature T0 set in step S103, a second fluctuation amount parameter ΔP2 of the number of passes is calculated.

[0053] For example, the control unit 15 calculates the second fluctuation amount parameter ΔP2 in the following manner. First, the control unit 15 calculates the finishing temperature T 1f and the total number of passes in the finishing phase, N 1p is read out and acquired from the storage unit 12 etc. The control unit 15 calculates the temperature difference ΔT2 based on the formula 7. ΔT2=T 1f -T 2f (Formula 7)

[0054] Next, the control unit 15 sets the increased number of paths to (N 2p-N 1p ) and calculate the influence coefficient α2 based on Equation 8. α2=(N 2p -N 1p ) / ΔT2 (Equation 8)

[0055] Next, the control unit 15 calculates the second fluctuation amount 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 apparatus 10 determines whether the second fluctuation parameter ΔP2 calculated in step S108 is within a predetermined numerical range. In the present disclosure, the "predetermined numerical range" includes, for example, a range greater than -1 and equal to or less than 0. That is, the control unit 15 determines whether -1<ΔP2≦0.

[0057] When the control unit 15 determines that the second fluctuation amount parameter ΔP2 is not within the predetermined numerical range, it executes the process of step S110. When the control unit 15 determines that the second fluctuation amount parameter ΔP2 is within the predetermined numerical range, it executes the process of step S112. When the number of passes is reduced so that -1<ΔP2≦0, but the result is less than one pass, the control unit 15 ends the calculation and executes the process of step S112 because further calculations will only result in repeated overshooting.

[0058] In step S110, the control unit 15 of the hot rolling apparatus 10 determines the maximum load P max In updating the maximum load P max 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 maxIf it is determined that the maximum load P has not reached the lower limit, the control unit 15 executes the process of step S111. max When it is determined that ΔP2 has reached the lower limit, the control unit 15 executes the process of step S112. 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 to increase the number of passes, the calculation is terminated and the process of step S112 is executed.

[0059] In step S111, the control unit 15 of the hot rolling apparatus 10 judges whether the number of repetitions of the process has been reached. If the control unit 15 judges that the number of repetitions has not been reached, the control unit 15 repeats the process of step S106 again. That is, in step S109, the control unit 15 judges that the second fluctuation amount parameter ΔP2 is not within the predetermined numerical range, and in step S110, the control unit 15 max If it is further determined that the lower limit value is not reached, the maximum load P max The process is repeated from step S106 where the control unit 15 updates the maximum load P max If ΔP2 has not reached the lower limit or ΔP2≦−1, there is still room for further calculation regarding an increase or decrease in the number of passes, so a calculation based on a new ΔP2 is performed.

[0060] When the process of step S106 is repeated, the control unit 15 stores the finishing temperature T 1f and the total number of passes in the finishing phase, N 1p The finishing temperature T 2f and the total number of passes in the finishing phase, N 2p Furthermore, the control unit 15 repeatedly executes the same calculation process as above using the second fluctuation amount parameter ΔP2 instead of the first fluctuation amount parameter ΔP1.

[0061] For example, in step S106, the control unit 15 calculates the total load P tot Next, the control unit 15 acquires the total number N of passes in the finishing phase according to the second rolling schedule. 2p The control unit 15 obtains a new maximum load P' based on Equation 10 similar to Equation 4, in place of the first fluctuation amount parameter ΔP1 to the second fluctuation amount parameter ΔP2. max The control unit 15 calculates P max =P' max By doing so, the maximum load P max Further updates will be provided. P' max =P tot / (N 2p +ΔP2) (Equation 10)

[0062] For example, in step S108, the control unit 15 determines the finishing temperature T 1f and the total number of passes in the finishing phase, N 1p The finishing temperature T 2f and the total number of passes in the finishing phase, N 2p Instead of the above, the calculation processes of the formulas 7 to 9 are similarly executed.

[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 creates a new second rolling schedule in which the number of passes is increased compared to the existing first rolling schedule that was executed before the target finishing temperature T0 was set in step S103, using the maximum load P updated in step S106. max When there are a plurality of second rolling schedules calculated in step S108 by repeating the process through step S111, the control unit 15 sets the finishing temperature T 2f The second rolling schedule that is closest to the target finishing temperature T0 is selected.

[0064] In step S113, the control unit 15 of the hot rolling apparatus 10 sets the rolling schedule by a normal method 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, as in the second rolling schedule based on the processing from step S105 to step S112.

[0065] FIG. 4 is a first graph diagram for explaining an example of a process performed by the hot rolling apparatus 10 of FIG. 1. FIG. 5 is a second graph diagram for explaining an example of a process performed by the hot rolling apparatus 10 of FIG. 1. FIG. 6 is a third graph diagram for explaining an example of a process performed by the hot rolling apparatus 10 of FIG. 1. FIG. 7 is a fourth graph diagram for explaining an example of a process performed by the hot rolling apparatus 10 of FIG. 1. FIG. 8 is a fifth graph diagram for explaining an example of a process performed by the hot rolling apparatus 10 of FIG. 1. FIG. 9 is a sixth graph diagram for explaining an example of a process performed by the hot rolling apparatus 10 of FIG. 1.

[0066] 4 to 9 show a rolling schedule including a second rolling schedule in a finishing phase when a hot rolling method according to an embodiment is performed according to the flowchart shown in FIG. 2, based on a solid line graph of "valid". As a comparison object for the second rolling schedule, FIG. 4 to FIG. 9 show a rolling schedule when set by a normal method, based on a dashed line graph of "invalid". In each graph, the vertical axis shows the load applied to the steel plate in each pass in the rolling schedule of the hot rolling. The horizontal axis shows the plate thickness of the steel plate obtained in each pass. The hot rolling apparatus 10 controls the rolling mill 30 to perform hot rolling, with the pass with the largest plate thickness being the first pass and the pass with the smallest plate thickness being the last pass in each graph, and passes through each pass from right to left.

[0067] As shown in each graph, the maximum load P maxis reduced, and the number of passes is increased compared to the rolling schedule set by the normal method. In the finishing phase, the average load for all passes in the second rolling schedule is smaller than that in the rolling schedule set by the normal method. As described above, the control unit 15 of the hot rolling apparatus 10 controls the maximum load P max A second rolling schedule with reduced rolling pressure and increased number of passes has been successfully applied to the finishing phase of hot rolling.

[0068] The control unit 15 of the hot rolling apparatus 10 may display at least a part of the data of the graphs as shown in Figures 4 to 9 as necessary through the output unit 14. For example, the control unit 15 may display the graphs as shown in Figures 4 to 9 as they are through the output unit 14, or may display only one of the rolling schedule including the second rolling schedule and the rolling schedule set by the normal method through the output unit 14.

[0069] According to the hot rolling apparatus 10 of the embodiment described above, it is possible to reduce the number of rejected materials caused by scale by a simpler method that does not involve descaling. The hot rolling apparatus 10 creates a new second rolling schedule in which the number of passes is increased compared to the existing first rolling schedule, and updates the updated maximum load P max In this way, the hot rolling apparatus 10 can adjust the finishing temperature T 2f As a result, the hot rolling apparatus 10 can reduce rejected materials caused by scale.

[0070] The hot rolling apparatus 10 can achieve the finishing temperature T 2f Therefore, the hot rolling apparatus 10 can reduce the finishing temperature T 2f It is also possible to reduce the amount of scale generation.

[0071] The hot rolling equipment 10 sets a new target finishing temperature T0 in place of the planned finishing temperature set by the host computer 20. This enables the hot rolling equipment 10 to comprehensively manage the target finishing temperature T0 as information together with the actual design conditions in hot rolling of steel sheets.

[0072] Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art can make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included in the scope of the present disclosure. For example, functions included in each configuration or each step can be rearranged or omitted so as not to be logically inconsistent, and multiple configurations or steps can be combined or divided into one.

[0073] For example, a general-purpose electronic device such as a smartphone or a computer can be configured to function as the hot rolling apparatus 10 according to the embodiment described above. Specifically, a program describing the processing contents for realizing each function of the hot rolling apparatus 10 according to the embodiment is stored in the memory of the electronic device, and the program is read and executed by a processor of the electronic device. Therefore, the present disclosure can also be realized as a program executable by a processor.

[0074] Alternatively, the present disclosure may be realized as a non-transitory computer-readable medium storing a program executable by one or more processors to cause the hot rolling apparatus 10 according to one embodiment to execute each function. It should be understood that these are also included within the scope of the present disclosure.

[0075] For example, at least a part of the processing operations executed in the hot rolling apparatus 10 in the above-described embodiment may be executed in at least one of the host computer 20 and the rolling mill 30. For example, instead of the hot rolling apparatus 10, the host computer 20 or the rolling mill 30 itself may execute the above-described series of processing operations related to the hot rolling apparatus 10. At least a part of the processing operations executed in the host computer 20 may be executed in the hot rolling apparatus 10. At least a part of the processing operations executed in the rolling mill 30 may be executed in the hot rolling apparatus 10. [Explanation of symbols]

[0076] 1. Hot Rolling System 10 Hot rolling equipment 11 Communications Department 12 Storage section 13 Input section 14 Output section 15 Control section 20 top calculator 30 Rolling Mill N 1p , N 2p Total ΔP1 First fluctuation parameter ΔP2 Second fluctuation parameter P ave average load P f Final Pass Loading 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. Obtaining design conditions for hot rolling of steel plates; Setting a target finishing temperature of the steel plate, the target finishing temperature being associated with the acquired design conditions; Updating a maximum load in the hot rolling based on the set target finishing temperature; setting a new second rolling schedule, in which the number of passes is increased as compared with the existing first rolling schedule that was executed before the target finishing temperature was set, based on the updated maximum load; Including, Hot rolling method.

2. The hot rolling method according to claim 1, The method further includes calculating a first variation parameter of the number of passes based on a finishing temperature of the steel sheet in a final pass in the first rolling schedule, a temperature of the steel sheet in a pass one pass before the final pass, and the target finishing temperature, updating the maximum load includes updating the maximum load based on the first variation parameter. Hot rolling method.

3. The hot rolling method according to claim 1 or 2, The method further includes calculating a second fluctuation amount parameter of the number of passes based on the finishing temperature of the steel sheet in a final pass in the second rolling schedule calculated based on the updated maximum load, the total number of passes, and the target finishing temperature. Hot rolling method.

4. The hot rolling method according to claim 3, if it is determined that the second variation parameter is not within a predetermined numerical range, the process is repeated from updating the maximum load. Hot rolling method.

5. The hot rolling method according to claim 4, if it is further determined that the maximum load has not reached the lower limit value in updating the maximum load, the process is repeated again starting from updating the maximum load. Hot rolling method.

6. The hot rolling method according to claim 1 or 2, Setting the second rolling schedule includes selecting, from among a plurality of the second rolling schedules calculated by repeating the process, the second rolling schedule in which the finishing temperature of the steel plate is closest to the target finishing temperature. Hot rolling method.

7. A hot rolling apparatus including a control unit, The control unit is Obtaining design conditions for hot rolling of steel plates, Setting a target finishing temperature of the steel plate, which is associated with the acquired design conditions; updating a maximum load in the hot rolling based on the set target finishing temperature; A new second rolling schedule having an increased number of passes compared to an existing first rolling schedule that was executed before the target finishing temperature was set is set based on the updated maximum load. Hot rolling equipment.

8. For hot rolling equipment, Obtaining design conditions for hot rolling of steel plates; Setting a target finishing temperature of the steel plate, the target finishing temperature being associated with the acquired design conditions; Updating a maximum load in the hot rolling based on the set target finishing temperature; setting a new second rolling schedule, which has an increased number of passes compared to an existing first rolling schedule that was executed before the target finishing temperature was set, based on the updated maximum load; performing an action including program.

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