A method for automatically controlling rolling mill speed of an acid pickling continuous rolling mill train

Abstract

The application discloses a kind of pickling tandem rolling mill set rolling mill speed automatic control method, it is related to cold continuous rolling automation control technical field.The pickling tandem rolling mill set rolling mill speed automatic control method of the present application, if abnormal state constraint factor occurs in production line operation process, the effective cache amount of strip in loop is calculated in advance by rolling mill speed automatic control model, so as to judge the current optimal speed control mode of rolling mill, and implement automatic speed reduction operation to guarantee continuous, stable and efficient production, so that rolling mill operation is intelligent;When one or more conditions in rolling mill speed control conditions ① to ⑥ item determination condition are not satisfied, rolling mill speed reduction is executed;When condition ⑥ is satisfied, but one or more conditions in determination conditions ① to ⑤ are not satisfied, rolling mill entrance is reduced to 150mPm;When condition ⑥ is not satisfied, speed control strategy table is executed.

Description

Technical Field

[0001] This invention relates to the field of automated control technology for cold continuous rolling mills, and more specifically to an automatic control method for the mill speed of a pickling continuous rolling mill. Background Technology

[0002] To ensure continuous and stable operation of the production line, pickling and rolling mills are typically equipped with three loopers. These loopers act as buffers for the strip steel and coordinate the speeds of the entry section, pickling process section, exit edge trimming shear, and rolling mill process section. The goal is to ensure continuous and stable operation of the pickling and rolling mill within the process speed range.

[0003] like Figure 1 As shown, the basic production process of a certain 1720 pickling continuous rolling mill is as follows: raw material feeding → inlet section uncoiling (uncoiler) → straightening (straightening machine) → head and tail shearing (double layer shear) → welding (laser welding machine) → buffer strip (inlet looper) → tension straightening and descaling (tension straightener) → pickling (pickling process section) → rinsing and drying → buffer strip (intermediate looper) → edge trimming (outlet edge trimming shear) → buffer strip (outlet looper) → rolling (rolling mill process section) → slitting (outlet shear) → coiler → material transportation.

[0004] Typically, the three looper functions and speed control methods for each section of a pickling and rolling mill are as follows:

[0005] like Figure 2 As shown, the inlet looper, located between the inlet section and the pickling section, is used to store and release strip steel, ensuring continuous operation of the strip steel on the production line. The effective storage capacity of the looper must meet the coil changeover time at the inlet, including completing a series of tasks such as uncoiling, threading, deceleration, head and tail shearing, welding, and edge trimming to ensure continuous operation of the pickling section. The speed control of the inlet looper is constrained by the strip steel running speed V at the inlet section. R The strip running speed V of the pickling process section s The speed difference between the two, such as when V R equals V s When V is in synchronous operation, it indicates that the inlet looper speed control is in synchronous operation and the length of the strip stored in the inlet looper does not change; when V R Greater than V s When V indicates that the inlet looper speed control is in the filling state, the length of strip steel stored in the inlet looper continues to increase; when V R Less than V s When the speed control of the inlet looper is in the unloading state, the length of the strip stored in the inlet looper continues to decrease. Once the empty looper limit is reached, the strip in the pickling process section stops running.

[0006] like Figure 3As shown, the intermediate looper, located between the pickling section and the exit trimming shear, is used to store and release strip steel, ensuring continuous operation of the strip steel on the production line. The effective storage capacity of the looper is sufficient to support the continuous operation of the pickling section, including trimming and edge cutting. The speed control of the intermediate looper is limited by the strip steel running speed V in the pickling section. s With the export edge trimming and strip shearing running speed V j The speed difference between the two, such as when V j equals V s When the intermediate looper speed control is in synchronous operation, the length of the strip stored in the intermediate looper remains unchanged; when V s Greater than V j When V indicates that the inlet looper speed control is in the filling state, the length of strip steel stored in the inlet looper continues to increase; when V s Less than V j When the speed control of the inlet looper is in the unloading state, the length of the strip stored in the intermediate looper continues to decrease. Once the empty looper limit is reached, the strip of the outlet shearing will stop running.

[0007] like Figure 4 As shown, the exit looper, located between the exit trimming shear and the rolling mill process section, is used to store and release strip steel, ensuring continuous strip steel operation throughout the production line. The strip steel speed changes, particularly during trimming shear blade width adjustments, roll changes in the rolling mill area, and strip coil cutting at the mill exit. The exit looper speed control is constrained by the strip steel running speed V at the exit trimming shear. j With the mill inlet speed V z The speed difference between the two, such as when V z equals V j When V is in a synchronous operating state, it indicates that the speed control of the exit looper is in a synchronous operating state, and the length of the strip stored in the exit looper does not change; when V j Greater than V z When V is in the exit loop speed control state, it indicates that the length of strip steel stored in the exit loop is continuously increasing; when V j Less than V z When the speed control of the exit looper is in the unloading state, the length of strip steel stored in the exit looper continues to decrease, and the mill stops once the empty looper limit is reached.

[0008] Improper speed control can lead to problems such as insufficient strip buffer capacity within the looper, resulting in mill shutdowns and interruptions in continuous production. To ensure continuous and stable operation of the continuous rolling mill within a certain speed range and to avoid abnormal operating conditions such as equipment malfunctions, it is necessary to coordinate and control the speed of each section.

[0009] Current technology for controlling the mill speed of pickling continuous rolling mills involves operators monitoring the operation screen to track the speeds of the entry section, pickling process section, exit trimming shear, and rolling mill process section. When abnormal conditions occur, the effective storage capacity of the three loopers is judged based on experience to manually control the mill speed. However, this current technology for controlling mill speed has the following problems:

[0010] 1. Operators need to monitor the production process in real time and manually intervene to control the mill speed in order to eliminate abnormal factors.

[0011] 2. The judgment conditions for mill speed reduction rely on operating experience. In order to avoid the mill running out of sleeve due to the rapid emptying of the strip inside the looper, the mill inlet speed is directly reduced to the minimum strip threading speed of 30mPm, which affects product quality. Summary of the Invention

[0012] 1. The technical problem the invention aims to solve.

[0013] To address the problems existing in the speed control of existing pickling continuous rolling mills, this invention proposes an automatic speed control method for pickling continuous rolling mills. When abnormal conditions occur during production line operation, the effective buffer amount of strip steel in the looper is pre-calculated through the automatic speed control model of the rolling mill, thereby determining the current optimal speed control mode of the rolling mill and implementing automatic speed reduction operation, thus achieving continuous, stable and efficient production, while also reducing the labor intensity of operators.

[0014] 2. Technical Solution

[0015] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0016] An automatic speed control method for a pickling continuous rolling mill unit addresses abnormal conditions during production line operation. These abnormal conditions include weld re-welding, abnormal uncoiling and threading, edge blocking by the shearing cutter, edge width adjustment, or shearing blade replacement. The sequential automatic control system inputs the relevant section shutdown signal to the automatic speed control model. The model calculates the strip buffer capacity within the looper and the expected waiting time, then automatically executes a mill speed reduction function. By pre-calculating the effective strip buffer capacity within the looper, the model determines the optimal speed control mode and implements automatic speed reduction. This method is independent of human skill limitations, preventing uncontrolled mill shutdowns and ensuring continuous, stable, and efficient production. It also reduces the workload of operators and improves operational efficiency. The specific steps include:

[0017] Step 1: Signal detection input to the mill speed control model: The sequential control process automatic control system monitors the execution process of each section of the sequential control process. If a process step is not completed within the specified time, the abnormal shutdown signal of that section of the process is transmitted to the mill speed control model. This signal triggers the automatic speed reduction control function of the mill. After the sequential control process step is completed, the completion signal is transmitted to the mill speed control model again. This signal triggers the mill speed control model to switch to standby mode.

[0018] Step 2: Mill speed and looper quantity control: After the mill speed control model is put into operation, the effective buffer quantity of strip steel and the speed of the section in the inlet looper, intermediate looper and outlet looper are calculated. Then, the judgment conditions set in the model are compared and analyzed to determine whether to implement mill speed reduction.

[0019] In a further technical solution, in step two, the effective buffer capacity of the strip in the inlet looper is 602~682m, the effective buffer capacity of the strip in the intermediate looper is 303~369m, and the effective buffer capacity of the strip in the outlet looper is 285~330m.

[0020] In a further technical solution, in step two, if one or more of the six judgment conditions ① to ⑥ defined in the mill speed control model are not met, the mill speed will be reduced. Among them, the region-related loopers under conditions ① and ④ are the inlet loopers, the region-related loopers under conditions ② and ⑤ are the intermediate loopers, and the region-related loopers under conditions ③ and ⑥ are the outlet loopers. The specific details of conditions ① to ⑥ are as follows:

[0021] ①: V R = V s Or V R > V s ;

[0022] ②: V s = V j Or V s > V j ;

[0023] ③: V j =V Z Or V j >V Z；

[0024] ④: The amount of loose-fitting loops at the entrance (A) is ≥ 50%;

[0025] ⑤: Intermediate loop quantity B ≥ 20%;

[0026] ⑥: Exported loose-fitting quantity C≥80%.

[0027] Further technical solutions, if condition ⑥ is met, but one or more of the judgment conditions ① to ⑤ are not met, the mill inlet speed is reduced to 150 mPm.

[0028] A further technical solution is to execute the speed control strategy table if condition ⑥ is not met.

[0029] A further technical solution involves a mill speed control strategy based on the principle of prioritizing efficiency under stable rolling conditions. This strategy employs segmented speed reduction to avoid abrupt changes in speed over a short period. The target value for segmented speed reduction is based on the exit looper quantity. The speed control strategy is illustrated in the table below:

[0030]

[0031] Where T is the process recovery waiting time, and H is the raw material thickness.

[0032] 3. Beneficial effects

[0033] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0034] This invention discloses an automatic speed control method for a pickling continuous rolling mill. During production line operation, if abnormal conditions occur, such as weld re-welding, abnormal uncoiling and threading, edge blocking by the shearing cutter, edge width adjustment, or shear blade replacement, the sequential control process automatic control system can input the relevant section shutdown signal to the automatic mill speed control model. The automatic mill speed control model calculates the strip buffer amount within the looper and the expected waiting time, then automatically executes the mill speed reduction function. By pre-calculating the effective strip buffer amount within the looper, the model determines the current optimal speed control mode and implements automatic speed reduction. This method is unaffected by human skill, preventing uncontrolled mill shutdowns and ensuring continuous, stable, and efficient production. It also reduces the labor intensity of operators, improves operational efficiency, and makes mill operation more intelligent. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the pickling and rolling mill process of the present invention;

[0036] Figure 2 This is a schematic diagram of the inlet looper speed control of the pickling continuous rolling mill unit of the present invention;

[0037] Figure 3 This is a schematic diagram of the intermediate looper speed control of the pickling continuous rolling mill unit of the present invention;

[0038] Figure 4 This is a schematic diagram of the outlet looper speed control of the pickling continuous rolling mill unit of the present invention.

[0039] Figure 5This is a flowchart illustrating the process flow when abnormal conditions occur in the pickling and rolling mill of the present invention.

[0040] In the diagram: V R - The strip running speed at the entrance section; V s - The strip running speed in the pickling process section; V j -Export cutting and shearing strip speed; V z - Mill inlet speed. Detailed Implementation

[0041] To further understand the content of this invention, a detailed description of the invention is provided in conjunction with the accompanying drawings.

[0042] Example 1

[0043] This embodiment provides an automatic speed control method for a pickling continuous rolling mill, such as... Figure 5 As shown, if abnormal conditions occur during production line operation, such as weld re-welding, abnormal uncoiling and threading, edge blocking by the cutting shear, adjustment of the cutting width, or replacement of the cutting blade, the sequential control process automatic control system can input the relevant section shutdown signal to the mill speed automatic control model. After calculating the strip buffer amount and expected waiting time within the looper, the mill speed automatic control model automatically executes the mill speed reduction function. By pre-calculating the effective strip buffer amount within the looper, the model determines the current optimal speed control mode of the mill and implements automatic speed reduction. This ensures that the mill is not affected by human skill, preventing uncontrolled shutdowns and ensuring continuous, stable, and efficient production. It also reduces the labor intensity of operators and improves operational efficiency. Specifically, the following steps are included:

[0044] Step 1: Signal detection input to the mill speed control model: The sequential control process automatic control system monitors the execution process of each section of the sequential control process. If a process step is not completed within the specified time, the abnormal shutdown signal of that section of the process is transmitted to the mill speed control model. This signal triggers the automatic speed reduction control function of the mill. After the sequential control process step is completed, the completion signal is transmitted to the mill speed control model again. This signal triggers the mill speed control model to switch to standby mode.

[0045] Step 2: Mill speed and looper quantity control: After the mill speed control model is put into operation, the effective buffer quantity of strip steel and the speed of the section in the inlet looper, intermediate looper and outlet looper are calculated. Then, the judgment conditions set in the model are compared and analyzed to determine whether to implement mill speed reduction.

[0046] In step two of this embodiment, as shown in Table 1, if one or more of the six judgment conditions ① to ⑥ in the mill speed control model are not met, the mill speed will be reduced; if condition ⑥ is met, but one or more of the judgment conditions ① to ⑤ are not met, the mill inlet speed will be reduced to 150 mPm; if condition ⑥ is not met, the speed control strategy table is executed, as shown in Table 2.

[0047] Table 1. Judgment Criteria for Mill Speed ​​Control

[0048]

[0049] Table 2 Rolling Mill Speed ​​Control Strategy

[0050]

[0051] Taking a 1720mm pickling and rolling mill as an example:

[0052] Product thickness specifications: Raw material 1.5~5.5 mm, finished product 0.3~3.0 mm

[0053] Width: Raw material 920~1600mm, finished product 900~1575mm

[0054] Effective length of loopers (maximum): Inlet looper 465m, Middle looper 203m, Outlet looper 235m

[0055] Speeds in each section: Maximum unwinding speed at the entrance section: 600 m / s; Threading speed: 60 m / s.

[0056] The pickling process has a maximum speed of 240 m / s and a threading speed of 30 m / s.

[0057] The maximum speed of the export edge trimmer is 330 m / s, and the threading speed is 30 m / s.

[0058] The maximum speed at the mill entrance section is 330 m / s, and the threading speed is 30 m / s.

[0059] The existing technology for controlling the mill speed of pickling continuous rolling mills is as follows: the operator monitors the operation screen and monitors the speed of the inlet section, pickling process section, exit edge trimming shear, and rolling mill process section. When an abnormal state occurs, the effective storage capacity of the three loopers is judged based on experience to manually control the mill speed. The specific control method is shown in Table 3.

[0060] Table 3. Factors Related to Mill Speed ​​Control

[0061]

[0062] Entrance loop speed difference: VR =V s Or V R >V s And the loose-leaf quantity A ≥ 50%

[0063] Intermediate loop speed difference: V s =V j Or V s >V j And the loose-leaf quantity B ≥ 20%

[0064] Export looper speed difference: V j =V Z Or V j >V Z And the loose-leaf quantity C ≥ 60%

[0065] When the above conditions are met simultaneously, the effective buffer capacity of the strip inside the looper can meet the needs of the mill operating at the highest process speed. When abnormal conditions occur, such as when the weld quality inspection fails and re-welding is required, the looper capacity will not be able to maintain the mill operating at the highest process speed. Operators will then manually intervene to reduce the mill speed. The target control range for the speed reduction varies depending on the product specifications being produced. For thicker specifications (raw material 5.5~3.0mm), the minimum mill inlet speed is 30mPm, and for thinner specifications (raw material 2.7~1.5mm), the minimum mill inlet speed is 45mPm. By reducing the mill speed, it is possible to avoid the mill from shutting down due to abnormal conditions, which could cause the strip inside the looper to quickly run out of buffer capacity and interrupt continuous production.

[0066] The above example, using weld re-welding as an illustration, demonstrates that when abnormal conditions affecting the production line cause the effective buffer capacity of the strip within the looper to be insufficient to meet the maximum process speed, operators, based on experience, manually intervene to reduce the mill speed to prevent the strip from rapidly emptying the looper and causing a shutdown. The technical methods for controlling mill speed when other abnormal conditions occur are the same and will not be detailed further.

[0067] In this embodiment, the mill speed control strategy is based on the principle of efficiency priority under stable rolling conditions. The following should be noted when using it: First, it has the ability to maintain high-speed operation continuously; second, it avoids operation under extreme low-speed conditions; third, it adopts segmented speed reduction to avoid multiple rapid speed reductions and switching in a short period of time; fourth, the target value of segmented speed reduction is designed based on the exit looper quantity; the specific limit value can be established in practice according to different product specifications.

[0068] Example 2

[0069] This embodiment of the automatic speed control method for a pickling continuous rolling mill has the same basic structure as Embodiment 1, but differs and is improved in that: the raw material thickness H=2.5mm, the exit looper volume is 78%, the weld in the inlet section is re-welded, and condition ⑥ is not met, the speed control strategy table is executed, as follows:

[0070] 1. The automatic control system of the sequential control process in the entrance area outputs the weld re-welding signal to the automatic speed control model of the rolling mill, triggering the model function to be put into operation;

[0071] 2. The speed model calculates the effective buffer amount of strip steel in the looper and the speed of the section. The comparison and judgment are as follows: the exit looper amount C=78% <80% does not meet condition ⑥, and the rolling mill executes automatic speed reduction (as shown in Table 1).

[0072] 3. For weld re-welding with T=96 seconds, raw material thickness H=2.5mm, and exit looper quantity C=78%, the speed adjustment control strategy is as follows (as shown in Table 2): the mill inlet speed is reduced to 90 mPm. If the weld re-welding sequence control process in the inlet section does not recover within the waiting time, the mill inlet speed is reduced again to 75 mPm when the exit looper quantity is less than 60%. If the weld re-welding sequence control process in the inlet section does not recover within the waiting time, the mill inlet speed is reduced again to 60 mPm when the exit looper quantity is less than 50%.

[0073] 4. The mill inlet speed is maintained at 60 m / s until the sequential control process is completed. If it is not completed, no further speed adjustment will be made.

[0074] Example 3

[0075] This embodiment of the automatic speed control method for a pickling continuous rolling mill has the same basic structure as Embodiment 1, but differs and is improved in that: when the raw material thickness H=3mm, the exit looper amount is 68%, the uncoiling and threading in the inlet section is abnormal, and condition ⑥ is not met, the speed control strategy table is executed, as follows:

[0076] 1. The automatic control system of the sequential control process in the entrance area outputs the uncoiling and threading signal to the automatic speed control model of the rolling mill, triggering the model to start its function;

[0077] 2. The speed model calculates the effective buffer amount of strip steel in the looper and the speed of the section. The comparison and judgment are as follows: the exit looper amount C=68% <80% does not meet condition ⑥, and the rolling mill executes automatic speed reduction (as shown in Table 1).

[0078] 3. If the uncoiling and threading process is abnormal (T=62 seconds, raw material thickness H=3.0mm, exit looper quantity C=68%), the speed control strategy is adjusted according to the speed (as shown in Table 2). The mill inlet speed is reduced to 60mPm. If the uncoiling and threading sequential control process in the inlet section is not restored within the waiting time, the mill inlet speed is reduced to 45mPm again when the exit looper quantity is less than 60%.

[0079] 4. The mill inlet speed of 45 mPm shall be maintained until the sequential control process is restored. If it is not restored, no further speed adjustment shall be made.

[0080] Example 4

[0081] This embodiment of the automatic speed control method for a pickling continuous rolling mill has the same basic structure as Embodiment 1, but with the following differences and improvements: the raw material thickness H=2.5mm, the exit looper amount is 75%, the exit section is trimming and blocking, and condition ⑥ is not met, the speed control strategy table is executed, as follows:

[0082] 1. The automatic control system of the exit section sequential control process outputs the edge cutting and blocking signal to the automatic speed control model of the rolling mill, triggering the model function to be put into operation;

[0083] 2. The speed model calculates the effective buffer amount of strip steel in the looper and the speed of the section, and compares and judges: the exit looper amount C=75% <80% does not meet condition ⑥, and the rolling mill executes automatic speed reduction (as shown in Table 1).

[0084] 3. With edge trimming and blocking T=120 seconds, raw material thickness H=2.5mm, and exit looper quantity C=75%, the speed adjustment control strategy is as shown in Table 2. The mill inlet speed is reduced to 75mPm. If the edge trimming and blocking sequential control process is not restored within the waiting time, the mill inlet speed is reduced to 60mPm again when the exit looper quantity is less than 60%. If the edge trimming and blocking sequential control process is not restored within the waiting time, the mill inlet speed is reduced to 45mPm again when the exit looper quantity is less than 50%.

[0085] 4. The mill inlet speed of 45 mPm shall be maintained until the sequential control process is restored. If it is not restored, no further speed adjustment shall be made.

[0086] Example 5

[0087] This embodiment of the automatic speed control method for a pickling continuous rolling mill has the same basic structure as Embodiment 1, but with the following differences and improvements: When the raw material thickness H = 4.5 mm, the exit looper volume is 75%, the exit section edge trimming width is adjusted, and condition ⑥ is not met, the speed control strategy table is executed, as follows:

[0088] 1. The automatic control system of the exit section sequential control process outputs the edge trimming width adjustment signal to the automatic speed control model of the rolling mill, triggering the model function to be put into operation;

[0089] 2. The speed model calculates the effective buffer amount of strip steel in the looper and the speed of the section, and compares and judges: the exit looper amount C=75% <80% does not meet condition ⑥, and the rolling mill executes automatic speed reduction (as shown in Table 1).

[0090] 3. With the trimming shear width adjustment T=30 seconds, raw material thickness H=4.5mm, and exit looper quantity C=75%, the speed adjustment control strategy is based on the speed adjustment (as shown in Table 2). If the mill inlet speed is reduced to 90mPm and the trimming shear width adjustment sequential control process does not recover within the waiting time, the mill inlet speed will be reduced to 75mPm again when the exit looper quantity is less than 60%. If the trimming shear blocking sequential control process does not recover within the waiting time, the mill inlet speed will be reduced to 60mPm again when the exit looper quantity is less than 50%.

[0091] 4. The mill inlet speed is maintained at 60 m / s until the sequential control process is completed. If it is not completed, no further speed adjustment will be made.

[0092] Example 6

[0093] This embodiment of the automatic speed control method for a pickling continuous rolling mill has the same basic structure as Embodiment 1, but the differences and improvements are as follows: the raw material thickness H=2.0mm, the exit looper volume is 78%, the exit section edge cutting shear is changed, and condition ⑥ is not met, the speed control strategy table is executed, as follows:

[0094] 1. The automatic control system of the exit section sequential control process outputs the edge cutting and shear blade switching signal to the automatic speed control model of the rolling mill, triggering the model function to be put into operation;

[0095] 2. The speed model calculates the effective buffer amount of strip steel in the looper and the speed of the section. The comparison and judgment are as follows: the exit looper amount C=78% <80% does not meet condition ⑥, and the rolling mill executes automatic speed reduction (as shown in Table 1).

[0096] 3. With the trimming shear width adjustment T=78 seconds, raw material thickness H=2.0 mm, and exit looper quantity C=78%, the speed adjustment control strategy is as shown in Table 2. If the mill inlet speed is reduced to 75 mPm and the trimming shear blade change sequence control process is not restored within the waiting time, the mill inlet speed will be reduced to 60 mPm again when the exit looper quantity is less than 60%. If the trimming shear blade change sequence control process is not restored within the waiting time, the mill inlet speed will be reduced to 45 mPm again when the exit looper quantity is less than 50%.

[0097] 4. The mill inlet speed of 45 mPm shall be maintained until the sequential control process is restored. If it is not restored, no further speed adjustment shall be made.

[0098] Example 7

[0099] This embodiment of an automatic speed control method for a pickling continuous rolling mill has the same basic structure as Embodiment 1, but differs and is improved in that: condition ⑥ is met, but one or more of the judgment conditions ①②③④⑤ are not met, such as raw material thickness H=3.0mm, exit looper amount 82%, abnormal uncoiling and strip threading in the inlet section, and strip running speed V in the inlet section. R =85mPm, strip running speed V in pickling process section s =110mPm, perform the following operations:

[0100] 1. The automatic control system of the sequential control process in the entrance area outputs the uncoiling and threading signal to the automatic speed control model of the rolling mill, triggering the model to start its function;

[0101] 2. The velocity model calculates the effective buffer capacity of the strip within the looper and the velocity of the section. Comparison and judgment: The exit looper capacity C = 85% > 80%, satisfying condition ⑥, but V... R <V s If condition ① is not met, the rolling mill will automatically reduce its speed (as shown in Table 1).

[0102] 3. Reduce the speed at the mill inlet to 150 mPm until the outlet looper is less than 80% of the looper capacity, then implement the speed adjustment control strategy (as shown in Table 2) to implement segmented speed reduction. See Specific Examples 2 to 6 for the implementation method and steps.

[0103] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for automatic speed control of a pickling continuous rolling mill, characterized in that: If abnormal conditions occur during production line operation, the sequential control process automatic control system can input the relevant section shutdown signal into the mill speed automatic control model. After calculating the strip buffer amount and expected waiting time in the looper, the mill speed automatic control model automatically executes the mill speed reduction function, which specifically includes the following steps: Step 1: Signal detection input to the mill speed control model: The sequential control process automatic control system monitors the execution process of each section of the sequential control process. If a process step is not completed within the specified time, the abnormal stop signal of that section of the process is transmitted to the mill speed control model. The abnormal stop signal triggers the automatic speed reduction control function of the mill. After the sequential control process step is completed, the completion signal is transmitted to the mill speed control model, which then triggers the mill speed control model to switch to standby mode. Step 2: Mill speed and looper quantity control: After the mill speed control model is put into operation, the effective buffer quantity of strip steel and the speed of the section in the inlet looper, intermediate looper and outlet looper are calculated. Then, the judgment conditions set in the model are compared and analyzed to determine whether to implement mill speed reduction.

2. The automatic speed control method for a pickling continuous rolling mill according to claim 1, characterized in that: Abnormal conditions include weld re-welding, abnormal uncoiling and threading, edge blocking by shearing, edge width adjustment, and shear blade replacement by shearing.

3. The automatic speed control method for a pickling continuous rolling mill according to claim 1, characterized in that: In step two, the effective buffer capacity of the strip in the inlet looper is 602~682m, the effective buffer capacity of the strip in the intermediate looper is 303~369m, and the effective buffer capacity of the strip in the outlet looper is 285~330m.

4. The automatic speed control method for a pickling continuous rolling mill according to claim 2, characterized in that: In step two, if one or more of the six judgment conditions ① to ⑥ defined in the mill speed control model are not met, the mill speed will be reduced. Among them, the region-related loopers under conditions ① and ④ are the inlet loopers, the region-related loopers under conditions ② and ⑤ are the intermediate loopers, and the region-related loopers under conditions ③ and ⑥ are the outlet loopers. The specific details of conditions ① to ⑥ are as follows: ①: V R = V s Or V R > V s ; ②: V s = V j Or V s > V j ; ③: V j =V Z Or V j >V Z ; ④: The amount of loose-fitting loops at the entrance (A) is ≥ 50%; ⑤: Intermediate loop quantity B ≥ 20%; ⑥: Exported looper quantity C ≥ 80%; Where: V R - The strip running speed at the entrance section; V s - The strip running speed in the pickling process section; V j -Export cutting and shearing strip speed; V z - Mill inlet speed.

5. The automatic speed control method for a pickling continuous rolling mill according to claim 4, characterized in that: If condition ⑥ is met, but one or more of the judgment conditions ① to ⑤ are not met, the mill inlet speed is reduced to 150 mPm.

6. The automatic speed control method for a pickling continuous rolling mill according to claim 4, characterized in that: If condition ⑥ is not met, execute the speed control strategy table.

7. The automatic speed control method for a pickling continuous rolling mill according to claim 6, characterized in that: The mill speed control strategy is based on the principle of prioritizing efficiency under stable rolling conditions. Its segmented speed reduction avoids abrupt changes in speed reduction over a short period of time. The target value for segmented speed reduction is based on the exit looper quantity. The speed control strategy is described in the table below: Where T is the process recovery waiting time, and H is the raw material thickness.

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