A method for controlling the width of hot rolling

Abstract

This invention relates to the field of steel rolling processes, and more particularly to a hot-rolled width control method. After the slab exits the furnace and arrives at the width-fixing mill of the roughing mill, the actual width of the slab in its hot state is measured. The primary control system compares the actual width with a theoretical width reference value. If the deviation exceeds a preset threshold, the actual width is uploaded to the secondary data model. The secondary data model re-determines the roll gap setting values ​​for each pass of the E1 and E2 vertical rolls and transmits these values ​​back to the primary control system. The primary control system issues setting commands based on the roll gap setting values ​​to adjust the roll gaps of the E1 and E2 vertical rolls. The advantages of this invention are: it achieves rapid response to slab width fluctuations, significantly improving the finished width accuracy of hot-rolled strip steel; when the actual slab width deviates beyond the theoretical value, the system dynamically adjusts the vertical roll gaps, avoiding vertical roll overload or equipment jamming due to width exceeding limits, effectively reducing the risk of equipment accidents.

Description

Technical Field

[0001] This invention relates to the field of steel rolling processes, and more particularly to a method for controlling the width of hot-rolled steel. Background Technology

[0002] In the production of hot-rolled strip steel, width control accuracy is one of the key technical indicators for measuring product quality. Whether the finished strip width meets the specification requirements directly affects the yield and the processing quality of subsequent processes.

[0003] Currently, hot rolling production lines generally employ a two-level process control system for setting and optimizing rolling parameters. The accuracy of strip width control mainly depends on the learning effect of the two-level data model, and the calculation accuracy of this model is affected by the actual width of the slab. To improve energy efficiency and reduce production costs, modern hot rolling production lines widely adopt hot charging or direct charging processes, that is, the slab is directly fed into the heating furnace or directly into the rolling line at a high temperature.

[0004] In existing technologies, width control typically relies on cold-state slab dimensions upon warehousing or slab data transmitted during steelmaking. However, since the continuous casting machine's casting speed directly affects slab width, it's impossible to obtain the accurate width of the slab in its hot state in real time, making it difficult for the secondary data model to respond promptly to fluctuations in the actual slab width. When the actual slab width deviates significantly from the theoretical value, continuing rolling according to the original parameters will lead to the following problems: 1. Decreased width accuracy of finished steel strips can easily lead to defective products with width exceeding tolerances, reducing product yield.

[0005] 2. If the actual width of the slab exceeds the allowable range of the equipment, it may cause the vertical roller to overload, the equipment to jam or even be damaged, leading to equipment safety accidents, increasing maintenance costs and downtime losses.

[0006] 3. To ensure width accuracy, manual intervention or machine shutdown for adjustment is usually adopted, which seriously affects the production efficiency of the rolling line and contradicts the high efficiency and energy-saving goals pursued by hot charging and direct charging processes.

[0007] Therefore, how to achieve high-precision width control of hot-rolled strip steel when the actual width of the slab fluctuates, while ensuring the continuous and efficient operation of the rolling line, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] The purpose of this invention is to provide a hot-rolled width control method. The method measures the actual width of the slab under hot conditions online. After the primary control system judges the deviation, it triggers the secondary data model to dynamically reset the roll gap values ​​of each pass of the E1 and E2 vertical rolls. The roll gap adjustment is completed under the premise that the width fixing machine maintains normal production operation. This invention can effectively cope with the fluctuation of the actual width of the slab, improve the accuracy of the width of the finished strip steel, reduce the number of defective products, and ensure the continuous and efficient operation of the rolling line.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A method for controlling the width of hot-rolled steel, comprising: When the slab reaches the width stabilizing mill of the roughing mill after exiting the furnace, the actual width of the slab under hot condition is measured by the guide ruler of the width stabilizing mill and the actual width is fed back to the primary control system. The primary control system compares the actual width with the theoretical width benchmark value. If the deviation exceeds a preset threshold, the actual width is uploaded to the secondary data model. The secondary data model, based on the preset total width reduction amount used to allocate between each rolling pass, redetermines the roll gap setting value for each pass of the E1 and E2 vertical rolls, and transmits the roll gap setting value back to the primary control system. The primary control system issues setting commands based on the roll gap setting value to adjust the roll gap of vertical rolls E1 and E2; If the deviation is less than or equal to the preset threshold, the current rolling parameters are maintained and the re-determination operation of the secondary data model is not triggered. During the dynamic adjustment process, the width-fixing machine continues to operate normally.

[0010] Before measuring the actual width of the slab in its hot state, the slab is centered using the guide ruler of the width stabilizing machine.

[0011] The content redefined in the secondary data model includes the width reduction of each pass of the E1 and E2 vertical rollers.

[0012] When redetermining the vertical roll gap setting value, the secondary data model uses the slab width side pressure as an input parameter in the calculation, and the expression is: Roll gap setting value = target width for this pass - reduction for this pass; Current pass reduction = Corrected reduction + Original calculated current pass reduction; Corrected reduction = Distributed reduction × (1 + β × H / W) tar ); in: β represents the lateral pressure deformation coefficient. For E1, the first and third passes have β = 0.03~0.05; for E2, the first and third passes have β = 0.01~0.03. H represents the slab thickness, in mm; Wta This indicates the target width for this pass, in mm.

[0013] During the dynamic adjustment process, when the slab passes through the width-fixing machine, the roll gaps of the E1 and E2 vertical rolls have been rearranged.

[0014] Also includes: During the slab measurement process, the width of the slab head and tail is measured by the front and rear sections of the guide ruler of the width fixing machine, the wedge data of the slab is collected, and uploaded to the first-level control program. The primary control system divides the slab into two sections, front and back, determines whether the width deviation of each section exceeds the threshold or whether the width change rate exceeds the threshold, and uploads the data to the secondary data model. The secondary data model is based on data and, according to the preset total width reduction amount used to allocate between each rolling pass, solves the dynamic roll gap setting value of each pass of E1 and E2 vertical rolls as the longitudinal position of the slab changes, and sends it to the primary control system in combination with the slab speed prediction. The primary control system controls the E1 and E2 vertical rollers to adjust the roller gap in real time during the slab passage process in order to perform segmented dynamic matching.

[0015] The primary control system issues instructions based on the redefined roll gap setpoint to adjust the roll gap of vertical rolls E1 and E2.

[0016] The preset threshold range is -10~10mm.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. By measuring the actual width of the slab in its hot state in real time using the guide ruler of the width-fixing machine, the traditional control method that relies on theoretical values ​​or lagging data is replaced, enabling a rapid response to slab width fluctuations and significantly improving the finished width accuracy of hot-rolled strip steel. 2. When the actual width of the slab deviates from the theoretical value by more than the limit, the system dynamically adjusts the gap between the vertical rollers to avoid overloading of the vertical rollers or equipment jamming due to the excessive width, effectively reducing the risk of equipment accidents. 3. Throughout the dynamic adjustment process, the width-fixing machine maintains normal operation, and the roll gap adjustment is completed before the slab arrives, without interrupting the rolling line production, thus achieving the unity of high-precision control and continuous and efficient production; 4. Reduce the production of products with non-conforming width, improve product yield, and avoid downtime for maintenance due to equipment accidents, thereby effectively reducing production costs; 5. When adopting the optimization scheme, the width measurement system enables segmented dynamic roll gap adjustment, effectively compensating for the uneven width of the slab along the length direction and further improving the overall width accuracy. Detailed Implementation

[0018] The present invention will now be described in detail, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0019] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods. Example 1:

[0020] A method for controlling the width of hot-rolled steel, comprising: S1. Measurement and centering of slab width in hot state; After the slab exits the furnace and arrives at the width stabilizing mill of the roughing mill, the slab is first centered using the guide ruler of the width stabilizing mill to obtain the actual width value of the slab on the hot scale, and the width difference between the head and tail of the slab is measured. Subsequently, the guide ruler is used to measure the actual width of the slab in the hot state, and the measured actual width value is fed back to the primary control system.

[0021] Suppose there is a slab to be rolled, with theoretical dimensions of 200mm thickness, 1250mm width, and 11200mm length. Its theoretical width in the hot state is 1282mm. Measured by the guide ruler of the width sizing mill, the actual width of the slab in the hot state is 1310mm. This measurement is transmitted to the primary control system in real time.

[0022] S2, Deviation Judgment and Data Upload; The primary control system compares the received actual width of the slab in its hot state with a preset theoretical width benchmark. If the deviation between the two exceeds a preset threshold, the primary control system determines that the current rolling parameters are mismatched and uploads the actual width value to the secondary data model.

[0023] If an optimization scheme is adopted, the primary control system will also divide the slab into several logical segments (such as head and tail) along the length direction, determine whether the width deviation of each segment exceeds the threshold or whether the width change rate between adjacent segments exceeds the preset threshold, and upload the data to the secondary data model.

[0024] For example, the primary control system compares the measured width of 1310mm with the theoretical width of 1282mm and calculates the deviation as 28mm. Since 28mm is greater than the preset ±10mm deviation threshold, the primary control system determines it to be an abnormal situation and then uploads the actual width of 1310mm to the secondary data model.

[0025] S3. Re-determination of roll gap setting value; After receiving the data uploaded by the primary control system, the secondary data model redetermines the roll gap setting values ​​for each pass of the E1 and E2 vertical rolls based on the preset model used to allocate the width reduction deviation between each rolling pass.

[0026] Width reduction deviation is the total width reduction achieved through side pressure from the vertical rolls during rolling to eliminate the discrepancy between the measured and theoretical width. This width reduction deviation cannot be achieved independently in a single pass; it needs to be distributed across multiple rolling passes using the E1 and E2 vertical rolls to avoid excessive reduction in a single pass, which could lead to rolling instability or equipment overload. The allocation model determines the proportion of reduction that each pass should bear based on slab characteristics, equipment capacity, and process requirements. The roll gap setting for each pass is essentially the final roll gap opening calculated based on the allocated reduction for that pass, combined with factors such as slab thickness and side pressure effect.

[0027] In summary: Width reduction deviation → Inter-pass distribution (reduction distribution model) → Reduction amount of each pass → Converted to the roll gap setting value of each pass.

[0028] For example, given the following conditions: Theoretical width of slab (hot): 1282 mm; Actual width of slab (hot state): 1310 mm; Target strip width: 1220mm; The original roughing mill vertical roll reduction for each pass was: E1 Pass 1 X, E1 Pass 3 X1, E2 Pass 1 X2, E2 Pass 3 X3; Width reduction deviation (total amount to be reduced): 1310-1282=28mm.

[0029] S31. Based on the allocation model, redetermine the reduction amount allocation for each pass; The preset allocation model, based on the slab specifications (200mm × 1250mm) and historical production data, adopts a fixed-ratio allocation method, setting the allocation coefficients and reduction amounts for each pass as follows: This allocation process is a concrete manifestation of the "model for allocating width reduction deviation between rolling passes".

[0030] S32. Convert the reduction amount of each pass into the roll gap setting value; Roll gap setting value = target width for this pass - reduction for this pass; However, the lateral pressure effect of the slab width needs to be considered (the metal will flow outward after being compressed, and the actual width reduction effect is less than the amount of compression), so the lateral pressure deformation coefficient β is introduced for correction.

[0031] For example, to facilitate calculation and display, the target width of each pass after vertical roll rolling is set to a single value. Slab thickness: H=200mm; Target width for this course: W tar =1282mm; Lateral compression deformation coefficient: E1, passes 1 and 3, β = 0.03~0.05. E2, passes 1 and 3, β = 0.01~0.03 Correction formula: Corrected reduction = Distributed reduction × (1 + β × H / W) tar ); The reduction amount for this pass = the corrected reduction amount + the original calculated reduction amount for this pass.

[0032] Calculation of the corrected roll gap setting: The process of redetermining the roll gap setting value includes: calculating the width reduction amount for each pass and using the slab width side pressure effect as an input parameter in the calculation.

[0033] Through the above allocation model, the secondary data model realizes the reasonable decomposition of the total width deviation to each pass, and finally calculates the required vertical roll gap setting value for each pass, thereby guiding the primary control system to complete precise width control.

[0034] The secondary data model is executed in the following manner, based on a pre-defined algorithm for allocating the total width reduction between each rolling pass: Method (1): Experience-based fixed-ratio allocation method; Based on historical production data and expert experience, a fixed set of pass reduction distribution coefficients is preset for slabs of different specifications. For example, for a typical specification, it is set that: the first pass of E1 accounts for 40% of the total width reduction, the third pass of E1 accounts for 30%, the first pass of E2 accounts for 20%, and the third pass of E2 accounts for 10%. Once the total width deviation is obtained, the width reduction of each pass is calculated according to this fixed proportion.

[0035] Method (2): Dynamic optimization allocation method based on equipment capacity; Based on the real-time capabilities of the vertical rolls in each pass (such as the current maximum allowable rolling force and the main motor current margin) and the instantaneous temperature of the slab, a set of optimal distribution coefficients is dynamically calculated. The optimization objective is to ensure that the rolling load (such as rolling force and torque) in each pass is relatively balanced, avoiding overload of any particular piece of equipment, while ensuring equipment safety. This can be achieved by solving a constrained nonlinear programming problem.

[0036] Method (3): Model-based adaptive allocation method; It incorporates a load distribution model that can learn from the rolling results of the previous slab (actual rolling force, width accuracy) and automatically adjust the pass reduction distribution coefficient of the next slab to continuously optimize rolling accuracy. For example, if it is found that the actual rolling force of the E1 vertical roll is far below its capacity limit, while the E2 vertical roll is close to overload, the model will automatically increase the distribution coefficient of the E1 pass and decrease the distribution coefficient of the E2 pass.

[0037] Specific calculation process: When the total width deviation is +28mm, the load distribution model built into the secondary data model first determines the slab material, temperature, and current equipment status. According to preset rules, the model determines that a fixed ratio distribution of "Method 1" should be used. The model calls the distribution coefficient table matching the current slab specifications and obtains the following coefficients: E1 first pass α1=0.30, E1 third pass α2=0.25, E2 first pass α3=0.25, E2 third pass α4=0.20.

[0038] Then, the algorithm calculates the width reduction for each pass: E1 first pass width reduction = 28mm × 0.30 = 8.4mm; E1 third pass width reduction = 28mm × 0.25 = 7.0mm; E2 first pass width reduction = 28mm × 0.25 = 7.0mm; E3 third pass width reduction = 28mm × 0.20 = 5.6mm.

[0039] Considering the lateral pressure effect of the slab width, the model corrects the aforementioned width reduction based on the geometry of the vertical roll, the slab thickness H, and the material's lateral pressure deformation coefficient β. Assuming the slab thickness H = 200 mm, the target width W for this pass... tar =1282mm, lateral pressure deformation coefficient: E1, passes 1 and 3, β=0.03~0.05. E2, passes 1 and 3, β=0.01~0.03, then the corrected formula for calculating the width reduction of each pass is: Corrected width reduction = Distributed compression amount × (1 + β × H / W) tar ); Taking the first lane of E1 as an example: Corrected width reduction = 8.4mm × (1 + 0.05 × 200mm / 1282mm) = 8.4mm × (1 + 0.0078) ≈ 8.47mm; Finally, the required roll gap setting value for each pass is calculated based on the corrected width reduction: E1 first pass roll gap setting value = target width of this pass - correction width reduction amount = 1282mm - 8.47 - X; E1 third pass roll gap setting value = 1282mm - 7.03 - X1; E2 first pass roll gap setting value = 1282mm - 7.03 - X2; E2 third pass roll gap setting value = 1282mm - 5.61 - X3.

[0040] The aforementioned roll gap setting is transmitted back to the primary control system.

[0041] If the optimization scheme is adopted, the secondary data model will solve the dynamic roll gap setpoint sequence of each pass of the E1 and E2 vertical rolls as the longitudinal position of the slab changes based on the received longitudinal width data, and combined with the real-time speed prediction of the slab, send the corresponding roll gap setpoint sequence to the primary control system in advance.

[0042] S4. Adjustment of vertical roller gap; The primary control system issues setting commands based on the roll gap setpoints transmitted from the secondary data model, adjusting the roll gaps of vertical rolls E1 and E2. If an optimized scheme is adopted, the primary control system controls vertical rolls E1 and E2 to adjust their roll gaps in real time during the slab's passage, achieving segmented dynamic matching.

[0043] The specific adjustment process is as follows: After receiving the latest E1 and E2 vertical roll gap settings (E1 first pass 1273.53mm, E1 third pass 1274.94mm, E2 first pass 1274.94mm, E2 third pass 1276.36mm) from the secondary data model, the primary control system immediately issues instructions to the E1 and E2 vertical rolls to readjust the roll gap according to the new settings. When different longitudinal sections of the slab pass through, if an optimized scheme is adopted, the roll gap is adjusted in real time according to a preset dynamic sequence. For example, when the head of the slab (wider width, measured 1315mm) passes through the E1 vertical roll, the roll gap is adjusted to 1273.00mm calculated for the head; when the middle of the slab (normal width, measured 1310mm) passes through, the roll gap is automatically adjusted to 1273.53mm; when the tail of the slab (slightly narrower width, measured 1305mm) passes through, the roll gap is automatically adjusted to 1274.20mm, thus achieving segmented dynamic matching.

[0044] S5. Handling when the deviation does not exceed the limit; If the primary control system determines that the deviation between the actual width and the theoretical width reference value is less than or equal to the preset threshold, it will maintain the current rolling parameters unchanged, not trigger the secondary data model re-determination operation, and the system will continue to carry out normal production according to the original settings.

[0045] For example, if the measured width is 1285mm, and the deviation from the theoretical width of 1282mm is 3mm, which is less than the threshold of ±10mm, then the primary control system will not upload the data to the secondary data model, and the E1 and E2 vertical rollers will continue to operate according to the original roller gap setting value.

[0046] S6. Ensuring production efficiency during dynamic adjustment; Throughout the dynamic adjustment process, the width-fixing mill remains in normal operation, ensuring that the production efficiency of the rolling line is not reduced. When the slab passes through the width-fixing mill, the roll gaps of the E1 and E2 vertical rolls have been rearranged or adjusted in real time to ensure continuous rolling on-site.

[0047] While the secondary data model recalculates the roll gap setting value, the width stabilizing machine continues to process the slab normally without any interruption or speed reduction. When the slab reaches the E1 and E2 vertical rolls after being processed by the width stabilizing machine, the roll gap of the vertical rolls has been rearranged according to the new setting value, achieving a seamless connection.

[0048] S7. Longitudinal width profile sensing and segmented dynamic adjustment; During the slab measurement process, the width of the slab head and tail is measured using the front and rear sections of the guide ruler of the width-fixing machine. The presence of a wedge shape in the slab is collected and uploaded to the primary control program.

[0049] For example, when the slab is measured by the guide ruler of the width slab measuring machine, the width of the slab's head and tail sections is measured using the front and rear sections of the guide ruler. The system collects data on whether the slab has a wedge shape and uploads this information to the primary control program. For instance, the average width of the slab head within the 0-2000mm range is 1315mm, and the average width of the tail within the 8000-11200mm range is 1305mm. This data is uploaded to the primary control system in real time for subsequent dynamic adjustments in segments.

[0050] This invention uses a guide ruler at the front of the width-fixing mill to measure the actual width of the slab in its hot state in real time, replacing the traditional control method that relies on theoretical values ​​or lagging data. This enables a rapid response to slab width fluctuations and significantly improves the finished width accuracy of hot-rolled strip steel. When the actual slab width deviates from the theoretical value by more than the limit, the system dynamically adjusts the vertical roll gap to avoid vertical roll overload or equipment jamming caused by width exceeding the limit, effectively reducing the risk of equipment accidents. Throughout the dynamic adjustment process, the width-fixing mill maintains normal operation, and the roll gap adjustment is completed before the slab arrives, without interrupting the rolling line production, achieving a balance between high-precision control and continuous, efficient production. This reduces the generation of width-defective products, improves product yield, and avoids downtime for maintenance due to equipment accidents, effectively reducing production costs. When using an optimized scheme, the width measurement system enables segmented dynamic roll gap adjustment, effectively compensating for the uneven width of the slab along its length, further improving the overall width accuracy.

Claims

1. A method for controlling the width of hot-rolled material, characterized in that, include: When the slab reaches the width stabilizing mill of the roughing mill after exiting the furnace, the actual width of the slab under hot condition is measured by the guide ruler of the width stabilizing mill and the actual width is fed back to the primary control system. The primary control system compares the actual width with the theoretical width benchmark value. If the deviation exceeds a preset threshold, the actual width is uploaded to the secondary data model. The secondary data model, based on the preset total width reduction amount used to allocate between each rolling pass, redetermines the roll gap setting value for each pass of the E1 and E2 vertical rolls, and transmits the roll gap setting value back to the primary control system. The primary control system issues setting commands based on the roll gap setting value to adjust the roll gap of vertical rolls E1 and E2; If the deviation is less than or equal to the preset threshold, the current rolling parameters are maintained and the re-determination operation of the secondary data model is not triggered. During the dynamic adjustment process, the width-fixing machine continues to operate normally.

2. The hot-rolled width control method according to claim 1, characterized in that, Before measuring the actual width of the slab in its hot state, the slab is centered using the guide ruler of the width stabilizing machine.

3. The hot-rolled width control method according to claim 1, characterized in that, The content redefined in the secondary data model includes the width reduction of each pass of the E1 and E2 vertical rollers.

4. The hot-rolled width control method according to claim 1, characterized in that, When redetermining the vertical roll gap setting value, the secondary data model uses the slab width side pressure as an input parameter in the calculation, and the expression is: Roll gap setting value = target width for this pass - reduction for this pass; Current pass reduction = Corrected reduction + Original calculated current pass reduction; Corrected reduction = Distributed reduction × (1 + β × H / W) tar ); in: β represents the lateral pressure deformation coefficient. For E1, the first and third passes have β = 0.03~0.05; for E2, the first and third passes have β = 0.01~0.

03. H represents the slab thickness, in mm; W ta This indicates the target width for this pass, in mm.

5. The hot-rolled width control method according to claim 1, characterized in that, During the dynamic adjustment process, when the slab passes through the width-fixing machine, the roll gaps of the E1 and E2 vertical rolls have been rearranged.

6. The hot-rolled width control method according to claim 1, characterized in that, Also includes: During the slab measurement process, the width of the slab head and tail is measured by the front and rear sections of the guide ruler of the width fixing machine, the wedge data of the slab is collected, and uploaded to the first-level control program. The primary control system divides the slab into two sections, front and back, determines whether the width deviation of each section exceeds the threshold or whether the width change rate exceeds the threshold, and uploads the data to the secondary data model. The secondary data model is based on data and, according to the preset total width reduction amount used to allocate between each rolling pass, solves the dynamic roll gap setting value of each pass of E1 and E2 vertical rolls as the longitudinal position of the slab changes, and sends it to the primary control system in combination with the slab speed prediction. The primary control system controls the E1 and E2 vertical rollers to adjust the roller gap in real time during the slab passage process in order to perform segmented dynamic matching.

7. The hot-rolled width control method according to claim 1, characterized in that, The primary control system issues instructions based on the redefined roll gap setting value to adjust the roll gap of vertical rolls E1 and E2.

8. The hot-rolled width control method according to claim 1, characterized in that, The preset threshold range is -10 to 10 mm.

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