A method for improving the control precision of the hot rolling rough rolling machine throw-off distance

Abstract

The present application relates to a kind of hot roughing mill throw-off distance control precision method, belong to steel metallurgical equipment automation control technical field.This method is applicable to reversible rough rolling process, by identifying current rolling pass, real-time monitoring rolling speed and combining steel flexibility parameter, dynamically calculate correction value z, for compensating slab slip distance.System according to the sum of pass basic distance, the delay sliding distance corresponding to rolling speed and correction value, determine target throw-off distance, and control its stability in the ±0.9 meter range before and after hot detector.This method constructs "pass+speed interval+steel characteristic" three-dimensional adaptive control model, significantly improves throw-off control precision, hot detector hit rate and production line rhythm stability.It has strong adaptability, high control precision, energy saving and efficiency improvement obvious advantages, suitable for the intelligent transformation and stability improvement application of various hot continuous rolling production line.

Description

Technical Field

[0001] This invention relates to the field of steel metallurgical equipment and steel rolling automation control technology, and in particular to a method for improving the control accuracy of steel throwing distance in hot rolling roughing mills. Background Technology

[0002] In hot strip rolling production, the roughing mill, as the primary and critical equipment for slab rolling, plays a decisive role in the overall production line rhythm. Currently, most hot strip rolling mills employ a single roughing mill for reversible rolling, where the slab is repeatedly passed through the roughing mill across multiple passes for reduction processing. Due to its advantages such as high process flexibility and compact equipment layout, reversible rolling is widely used in modern hot rolling production lines.

[0003] In this process mode, the throwing distance (i.e., the distance from when the slab is thrown from the roughing mill to its resting position after a certain rolling pass) becomes an important parameter affecting the production line rhythm and operating efficiency. If the throwing distance is too long, it will cause the reversal waiting time to be extended, affecting the material receiving rhythm of the final rolling mill; if it is too short, it is easy to cause problems such as plate head interference, plate tail steel accumulation, and hot inspection failure, reducing process stability and product quality.

[0004] Currently, automated hot strip rolling systems typically employ a hierarchical control mode. The secondary model generates roughing rolling paths and speed strategies based on process parameters such as steel grade, specifications, and target temperature, and sends control commands to the primary system, which then executes specific actions in real time, including speed adjustment and steel ejection rhythm control.

[0005] To achieve the shortest steel throwing distance control—that is, to ensure a minimum safe distance between the slab head and the roughing mill in both odd and even passes—dynamic adjustment via a primary control system is required. Traditional methods often rely on fixed empirical values ​​or simplified model settings, which are insufficient to adapt to variations in steel grades, speeds, and pass conditions, affecting actual control accuracy and production line stability. Therefore, a more precise and adaptive control method is urgently needed to optimize steel throwing distance control.

[0006] The purpose of this invention is to provide a method for optimizing the control accuracy of the steel throwing distance in the reversible roughing rolling process of hot continuous rolling production. This method aims to solve the problems of inaccurate steel throwing distance control, unstable rhythm, and low equipment operating efficiency caused by neglecting the rolling speed range and the flexibility differences of steel grades in the existing technology.

[0007] The specific objectives are as follows: 1. To achieve adaptive and precise control of the steel-throwing distance in each pass of the roughing mill, by introducing rolling speed range judgment and steel grade characteristic correction factors to dynamically compensate for the steel-throwing distance; 2. To minimize the steel-throwing distance and ensure that the slab head remains within ±0.9m of the hot inspection device before and after the roughing mill in odd and even passes, thereby improving the hot inspection hit rate and production line rhythm stability; 3. To reduce unplanned waiting time and reversing delay, and improve the overall line cycle control capability; 4. To enhance the working condition adaptability and intelligence level of the control system, providing technical support for intelligent manufacturing and energy saving in hot continuous rolling production lines.

[0008] The implementation of this invention can significantly improve the automation level of the roughing process, enhance the overall operating efficiency and product quality stability of the hot rolling production line, and has significant engineering value and promising prospects for promotion and application. Summary of the Invention

[0009] The purpose of this invention is to address the above-mentioned problems by providing a method for improving the accuracy of steel throwing distance control in hot rolling roughing mills.

[0010] The purpose of this invention is achieved as follows: a method for improving the control accuracy of the steel throwing distance in a hot rolling roughing mill, comprising the following aspects: (1) Pass identification and process segmentation control: the roughing process adopts a reversible rolling method, and the slab undergoes 5 or 7 passes of reciprocating rolling; (2) Rolling speed range judgment: the roughing rolling speed y is divided into 3 ranges, namely 2.0–3.5m / s, 3.5–4.5m / s, and 4.5–6.0m / s. The system monitors the rolling speed of the current pass in real time and judges its range, which is used for subsequent correction value lookup or function acquisition; (3) Introduction of steel grade flexibility parameter: for the differences in flexibility of different steel grades, a correction factor based on steel grade characteristics is introduced as the basis for compensation of the steel throwing slip distance; (4) Dynamic determination mechanism of correction value z: through the three-dimensional input of the correction factor of pass, speed range and steel grade characteristics, the steel throwing distance correction value z is calculated, z=k x ⋅f s , where: k x f is the baseline correction value for the current track number and speed range. s (5) Calculation and limit control of the final steel throwing distance: The final calculated target steel throwing distance D=S X +S delay +z, where: S X The base distance for the current track, in meters (m) and seconds (S). delay =V 2 / 2a, V is the rolling speed in m / s, and a is the deceleration in m / s. 2 Set control boundaries to ensure that the slab stays within ±0.9 meters before and after the heat inspection device; (6) Embedded closed-loop correction logic.

[0011] (6) The embedded closed-loop correction logic is as follows: during operation, the deviation between the actual distance of the steel throwing and the set target is continuously collected, and the model parameters are dynamically corrected according to the deviation trend to improve the control accuracy.

[0012] The beneficial effects of this invention are as follows: The hot rolling roughing mill steel throwing distance control method proposed in this invention, based on adaptive adjustment of pass, rolling speed range and steel grade flexibility, has the following beneficial effects: 1. Significantly improves the accuracy of steel throwing distance control: By introducing rolling speed partitioning and steel grade characteristic correction mechanism, the system can dynamically compensate for the slip distance deviation of each pass, making the steel throwing position of the slab more accurate under different working conditions. The actual control point is stable within ±0.9 meters of the hot inspection device before and after the roughing mill, improving the hot inspection hit rate and automatic identification success rate.

[0013] 2. Improve the stability of hot rolling rhythm and production line efficiency: Precisely control the steel throwing distance between odd and even passes to ensure that there is no waiting or conflict during the slab reversal process, effectively reduce unplanned downtime and rhythm disorder, and improve rhythm synchronization. It is expected to reduce reversal delay time by tens of hours per year, resulting in a considerable release of production capacity.

[0014] 3. Reduce scrap steel generation and abnormal roll replacement frequency: Improved steel throwing position accuracy avoids plate head damage and equipment impact caused by impact, steel piling or interference, reduces the number of scrap steel pieces and abnormal equipment downtime, indirectly extends the service life of work rolls, and reduces grinding costs and roll replacement frequency.

[0015] 4. Enhanced system intelligence and adaptability: The system has the ability to learn and adapt according to rolling speed and steel grade, and is suitable for fine control under mixed rolling conditions of multiple specifications and steel grades. It has good versatility and expandability and can be widely used in various hot continuous rolling production lines.

[0016] 5. Significant economic benefits and engineering value: Through the combined effects of cycle time optimization, loss control, roll replacement reduction and scrap reduction, it can generate millions of yuan in economic benefits annually, and has significant engineering promotion value and energy-saving and consumption-reducing benefits.

[0017] In summary, this invention can effectively overcome the shortcomings of traditional steel throwing control methods, and achieve refined, adaptive, and rhythmic control while ensuring process safety, thus helping hot strip rolling production lines to develop towards intelligent manufacturing and efficient operation. Attached Figure Description

[0018] The present invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a diagram of the control hardware of the present invention.

[0020] Among them: 1. Production line secondary automatic control system PLC, 2. Production line primary automatic control system PLC, 3. Roughing mill inlet heat detection sensor, 4. Roughing mill, 5. Slab. Detailed Implementation

[0021] This invention belongs to the field of steel metallurgical equipment and steel rolling automation control technology, specifically relating to a precise control method for the steel throwing distance in the roughing mill during hot rolling production, and particularly a steel throwing control strategy based on adaptive adjustment of pass, rolling speed range, and steel grade flexibility. This method is applicable to the automatic control system of the steel throwing section of the roughing mill in a hot continuous rolling production line. By introducing rolling speed zoning judgment and steel grade flexibility parameters, the target steel throwing distance for each pass is dynamically corrected, effectively improving the slab throwing accuracy and hot inspection hit rate. Compared with traditional methods, this invention fully considers the changes in rolling rhythm under different working conditions, realizing distance compensation control under multi-factor coupling, and has advantages such as fast response speed, strong adaptability, and high control accuracy. It can be widely applied to the intelligent transformation and rhythm stability improvement of hot continuous rolling production lines in steel enterprises, and has good engineering application value and promotion prospects.

[0022] The technical concept of this invention is based on the principle of "multi-factor adaptive compensation control," aiming to precisely control the steel-throwing distance of the slab in each pass during the reversible rolling process of hot strip mill roughing, thereby improving the hot inspection hit rate and production line rhythm stability. Its core concept mainly includes the following aspects: 1. Pass identification and process segmentation control: For the multi-pass (1~7) control objects in the reversible rolling process of hot strip mill roughing, the steel-throwing control logic is clearly embedded in the operation of each pass, differentiating between odd and even passes and directionality for differentiated control. The roughing process adopts a reversible rolling method, and the slab needs to be rolled back and forth through multiple passes (usually 7 passes). This invention first identifies the current rolling pass X∈{1,2,…,7}, controls the steel-throwing direction according to odd and even passes, and sets a basic steel-throwing target distance for different passes.

[0023] 2. Rolling Speed ​​Range Determination: This invention divides the roughing rolling speed y into multiple ranges (e.g., 2.0–3.5 m / s, 3.5–4.5 m / s, 4.5–6.0 m / s), and dynamically matches different steel-throwing distance correction strategies according to the speed range, dynamically assigning a correction value z to the current pass to adapt to the relaxation effect of different running speeds. The system monitors the rolling speed of the current pass in real time and determines its range for subsequent correction value lookup or function acquisition.

[0024] 3. Introduction of Steel Grade Flexibility Parameters: The parameter z is adjusted according to the rigidity / flexibility of the steel grade (e.g., high-strength steel / low-carbon steel) to take into account physical response, enabling more precise control of the slab sliding distance and improving control adaptability. Steel grade flexibility (rigidity, elongation, etc.) is introduced as an adjustment factor to construct a correlation model between material properties and slab sliding distance, achieving adaptive compensation control under different steel grades. Addressing the differences in flexibility among different steel grades (e.g., low-carbon steel, high-strength steel, stainless steel, etc.), this invention introduces a correction factor based on steel grade characteristics, such as a "rigidity index" or "flexibility coefficient," as a compensation basis for the slab sliding distance, improving the material adaptability of the control.

[0025] 4. Dynamic Determination Mechanism of Correction Value z: Based on the three-dimensional combination of "rolling pass X + speed range Y + steel grade flexibility factor", the correction value z is obtained by looking up a table or calculation, which is used to dynamically compensate for the traditional static steel throwing distance. Through the three-dimensional input of the pass, speed range and steel grade flexibility, the system obtains the steel throwing distance correction value z by looking up a table or calculation. This value is used to compensate for the actual deviation of the slab slippage distance, ensuring accurate control results.

[0026] 5. Final steel throwing distance calculation and limit control: Combining the baseline distance, speed delay distance, and dynamic correction value z, the final target steel throwing distance D=S is calculated. base +S velocity +z, and set control boundaries to ensure that the slab stays within ±0.9 meters before and after the heat inspection device.

[0027] 6. Embedded closed-loop correction logic: After the steel throwing action is completed, the z value of the next pass is corrected by the feedback of the deviation between the actual landing point and the target distance. During the operation of the system, the deviation between the actual steel throwing distance and the set target is continuously collected, and the model parameters are dynamically corrected according to the deviation trend to achieve closed-loop learning and improve control accuracy.

[0028] This invention achieves a leap from static setting to dynamic adaptive control through a logic chain of "pass number + speed range + steel grade characteristics → correction value → steel throwing distance adjustment". It has the advantages of precise working condition identification, rapid control response and strong adaptability to practical applications.

[0029] The secondary automatic control system PLC of the production line transmits the rolling speed V and the roughing mill pass signal of each pass to the primary automatic control system PLC of the production line via communication. When the roughing mill is rolling X passes (x=1, 2, 3, 4, 5, 6, 7), if the program determines the rolling speed y (roughing mill rolling speed) range, when the rolling speed is in the following ranges, namely 2.0 < y < 3.5 m / s; 3.5 < y < 4.5 m / s; 4.5 < y < 6.0 m / s, the steel throwing distance of the current pass of the roughing mill is increased by a correction value z (z = the correction value for the steel throwing distance of each pass of the roughing mill controlled in the program, this value changes according to the different steel grades and different speed ranges currently being rolled). The actual value is controlled within +0.9m of the front and rear hot inspection points of the roughing mill.

[0030] This invention is applied to the roughing mill of a hot continuous rolling production line, and is particularly suitable for single-unit reversible roughing rolling processes. The implementation process is as follows: 1. Basic parameter initialization: The system receives the rolling plan from the secondary model, including: the number of rolling passes X∈{1,2,…,7}, steel grade information (such as Q235, SPHC, Q550, etc.), target rolling speed y, etc.

[0031] Initialize the steel throwing distance S of each pass foundation X It is set based on experience or simulation models.

[0032] 2. Rolling speed range determination: The system monitors the actual rolling speed y after the current rolling pass is completed in real time and divides it into one of the following three speed ranges: Range I: 2.0 < y ≤ 3.5 m / s; Range II: 3.5 < y ≤ 4.5 m / s; Range III: 4.5 < y ≤ 6.0 m / s.

[0033] 3. Extraction of steel grade flexibility correction factor: Based on the rolled steel grade, the corresponding flexibility parameters (such as yield strength, elongation, etc.) are retrieved from the database, the system automatically maps the flexibility level, and assigns a correction factor fs accordingly.

[0034] For example: low carbon steel: fs=0.8, ordinary carbon steel: fs=1.0, high strength steel: fs=1.2.

[0035] 4. Calculation of correction value z: Based on the rolling speed range and flexibility factor, the correction value is set by referring to a table or through the following logic function: z=k x ⋅f s , where: k x This is the baseline correction value for the current track number and speed range (e.g., track number 1, range II, corresponding to k). x =0.25 m), f sFor example, if the flexibility factor of a certain steel grade is 1.2, the current pass is the 3rd pass, and the rolling speed is 4.0 m / s (belonging to interval II), and we find that k3 = 0.2, then z = 0.2 × 1.2 = 0.24 m.

[0036] 5. Calculation of target steel throwing distance: The final calculated target steel throwing distance is D=S X +S delay +z, where: S X The base distance for the current track, in meters (m) and seconds (S). delay =V 2 / 2a, V is the rolling speed in m / s, and a is the deceleration in m / s. 2 Set control boundaries to ensure that the slab remains within ±0.9 meters before and after the heat testing device.

[0037] 6. Distance Limitation and Verification Control: The system compares the calculation results with the control range of ±0.9m before and after the hot detection device. If it deviates from the limit, it will automatically adjust z or instruct the system to decelerate in advance to ensure the accuracy of the final landing point of the steel throwing.

[0038] 7. Control Command Issuance and Closed-Loop Feedback: The final target distance is converted into a first-level control command, controlling the real-time execution of the servo drive, roller speed, and steel throwing logic. After steel throwing is completed, the actual throwing distance is collected by a laser displacement meter or encoder, and deviation analysis is performed between the actual throwing distance and the target distance. This deviation is then used for adaptive updates of the correction value in the next pass.

[0039] Through the above implementation methods, the present invention realizes an adaptive steel throwing distance adjustment system that integrates pass segmentation, speed sensing, steel grade adaptation, dynamic correction and closed-loop feedback control. It can be widely adapted to hot rolling conditions with multiple varieties, speeds and rhythms, and significantly improve rolling stability and production efficiency.

[0040] The above description is only a specific embodiment of the present invention, but the structural features protected by the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A method for improving the control accuracy of steel throwing distance in a hot rolling roughing mill, characterized in that: Including the following aspects: (1) Pass identification and process segmentation control: The roughing process adopts a reversible rolling method, and the slab is rolled in 5 or 7 passes; (2) Rolling speed range judgment: The roughing rolling speed y is divided into 3 ranges, namely 2.0–3.5m / s, 3.5–4.5m / s, and 4.5–6.0m / s. The system monitors the rolling speed of the current pass in real time and determines its range, which is used for subsequent correction value lookup or function acquisition. (3) Introduction of steel grade flexibility parameters: In view of the differences in flexibility among different steel grades, a correction factor based on steel grade characteristics is introduced as the basis for compensation of the slip distance of steel throwing. (4) Dynamic determination mechanism of correction value z: The steel throwing distance correction value z is calculated by three-dimensional input of correction factors of pass number, speed range and steel grade characteristics, z=k x ⋅f s , where: k x f is the baseline correction value for the current track number and speed range. s It is a correction factor for the properties of steel grades; (5) Calculation and limit control of final steel throwing distance: The final calculated target steel throwing distance D=S X +S delay +z, where: S X The base distance for the current track, in meters (m) and seconds (S). delay =V 2 / 2a, V is the rolling speed in m / s, and a is the deceleration in m / s. 2 Set control boundaries to ensure that the slab remains within ±0.9 meters before and after the heat testing device; (6) Embedded closed-loop correction logic.

2. The method for improving the control accuracy of steel throwing distance in a hot rolling roughing mill according to claim 1, characterized in that: (6) The embedded closed-loop correction logic is as follows: during operation, the deviation between the actual distance of the steel throwing and the set target is continuously collected, and the model parameters are dynamically corrected according to the deviation trend to improve the control accuracy.

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