Control method for improving thickness precision of low-temperature controlled rolling thick plate

Abstract

The invention discloses a control method for improving the thickness precision of a low-temperature controlled rolling thick plate, which comprises the following steps of: optimizing a heating process: setting the heating temperature of a steel plate to be 1040-1060 DEG C, prolonging the total in-furnace time to be 10-12 hours, prolonging the effective heating time to be 4-5 hours, heating to be 1080 DEG C in a three-heating section, and cooling to be 1040 DEG C in a soaking section so as to ensure the temperature uniformity of the steel plate; a scientific research sample of the thermal expansion coefficient is cut after the low-temperature controlled rolling steel plate is rolled, the thermal expansion coefficient is measured every 25 DEG C within the interval of 600-1000 DEG C, and a rolling program is revised according to actually measured data; rolling reduction schedule arrangement is conducted, specifically, pre-arrangement is conducted according to the pre-arrangement schedule torque of 7800, it is guaranteed that the reduction rate of the last three passes of rough rolling is 10% or above, and the reduction amount of the last pass is maximized; according to the invention, the problem of temperature difference between the plate core and the surface of the low-temperature controlled rolled steel is effectively solved.

Description

Technical Field

[0001] The present invention relates to a control method for improving the thickness accuracy of cold-temperature controlled rolling thick plates. Background Art

[0002] In the field of metallurgical processing, the cold-temperature controlled rolling technology is widely used in the production of high-strength thick plates because it can improve the strength of steel plates and refine crystal grains. In the traditional cold-temperature controlled rolling process, the heating temperature of the steel billet is usually set at 1040°C, but the heating time is insufficient, resulting in a significant temperature difference between the core and the surface of the steel plate. Especially under the condition of low-temperature (≤1080°C) heating, the internal temperature distribution of the steel plate is uneven. During the subsequent rolling process, due to the large difference in the deformation resistance of the material, the actual rolling force and torque exceed the preset model range, causing the problem of excessive thickness. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a control method for improving the thickness accuracy of cold-temperature controlled rolling thick plates, effectively solving the problem of temperature difference between the core and the surface of cold-temperature controlled rolling steel plates, aiming at the above-mentioned shortcomings existing in the prior art.

[0004] The technical solution for the present invention to solve the above technical problems is as follows: A control method for improving the thickness accuracy of cold-temperature controlled rolling thick plates includes the following steps: Optimizing the heating process: Set the heating temperature of the steel plate at 1040 - 1060°C, extend the total time in the furnace to 10 - 12 hours, and increase the effective heating time to 4 - 5 hours. Among them, in the three-stage heating section, first heat up to 1080°C, and in the soaking section, cool down to 1040°C to ensure the temperature uniformity of the steel plate; Optimizing the rolling model: Cut a scientific research sample of the thermal expansion coefficient after rolling the cold-temperature controlled rolling steel plate, measure the thermal expansion coefficient every 25°C in the range of 600 - 1000°C, revise the rolling program according to the measured data, and extract the target value of the second-opening temperature ≤780°C, and transmit it to the level 1 system for optimizing and adjusting the head and tail thickness rolling impact compensation; Arranging the rolling reduction schedule: Pre-arrange the torque of the schedule at 7800, ensure that the reduction rate of the last three passes in rough rolling is more than 10%, and maximize the reduction amount of the last pass; Measuring and feedback adjusting the thickness after rolling: Measure the thickness of the rolled steel plate and record the data, and dynamically adjust the rolling program according to the measured results to optimize the thickness accuracy.

[0005] The further limited solution of the present invention: Preferably, in the optimization of the heating process, the temperature fluctuation range in the soaking section is controlled within ±5°C, and a segmented heating and cooling strategy is adopted to ensure uniform heating of the whole steel plate.

[0006] Preferably, in the optimization of the rolling model, the laser scanning method is used to measure the thermal expansion coefficient, and when revising the rolling program, the actual deformation resistance curve of the steel grade is combined to dynamically adjust the rolling force and torque parameters.

[0007] Preferably, in the rolling reduction schedule arrangement, the reduction ratios of the last three roughing passes are specifically as follows: the reduction ratio of the first pass is 12% - 15%, the second pass is 10% - 12%, the third pass is 8% - 10%, and the reduction amount of the last rolling pass is not less than 20% of the total reduction amount.

[0008] Preferably, the optimization adjustment of the head and tail thickness rolling impact compensation includes: Setting a dynamic compensation coefficient in the rolling pass table, and the compensation range is the 5 - meter section at the head and tail; According to the real - time feedback of the two - opening temperature target value, adjusting the compensation amplitude to ±0.5% - 1.0% of the thickness.

[0009] Preferably, for the post - rolling thickness measurement, a high - precision ultrasonic thickness gauge is used, and the measurement interval is to conduct a full - section scan every 2 meters, and the data is transmitted to the control system in real time for program iterative optimization.

[0010] The beneficial effects of the present invention are: By optimizing the heating process (the soaking section temperature control is ±5°C at 1040°C) and dynamically correcting the rolling model, the present invention effectively solves the problem of the temperature difference between the core and the surface of the low - temperature controlled - rolling steel plate. The thickness over - limit rate is reduced from 0.1% of the original process to 0.05%, and the thickness hitting accuracy is improved to within ±0.3 mm, greatly improving the product consistency; By optimizing the reduction schedule (the reduction ratio of the last three passes ≥10%) and pre - arranging the torque (the reference value is 7800), the fluctuation range of the rolling force is reduced by 30%, reducing the risk of equipment overload, and the service life of the roll and the drive system is extended by about 20%; By using an ultrasonic thickness gauge to conduct a full - section scan every 2 meters, the present invention realizes real - time data closed - loop control. The response time of the rolling program adjustment is shortened to within 5 seconds, and the continuous operation efficiency of the production line is increased by 8%. Specific Embodiments Embodiment

[0011] This embodiment provides a control method for improving the thickness accuracy of low - temperature controlled - rolling thick plates, including the following steps: Optimizing the heating process: setting the heating temperature of the steel plate to 1040°C, extending the total in - furnace time to 11 hours, and increasing the effective heating time to 4 hours. Among them, in the three - stage heating section, it is first heated to 1080°C, and in the soaking section, the temperature is reduced to 1040°C. The temperature fluctuation range in the soaking section is controlled within ±5°C, and a segmented heating and cooling strategy is adopted to ensure uniform heating of the whole steel plate; Optimization of rolling model: For the scientific research samples of thermal expansion coefficient cut after rolling the low-temperature controlled rolling steel plates, measure the thermal expansion coefficient every 25 °C in the range of 600 - 1000 °C. The thermal expansion coefficient is measured by the laser scanning method. When revising the rolling program, combine the actual deformation resistance curve of the steel grade, dynamically adjust the rolling force and torque parameters, revise the rolling program according to the measured data, and extract the target value of the second-opening temperature ≤ 780 °C, and transmit it to the level 1 system for optimized adjustment of the head and tail thickness rolling impact compensation; Arrangement of rolling reduction schedule: The torque of the pre-arranged schedule is pre-arranged at 7800. The reduction rate of the last three passes in rough rolling is guaranteed to be more than 10%, and the reduction of the last pass is maximized. The reduction rates of the last three passes in rough rolling are specifically: the reduction rate of the first pass is 12% - 15%, the second pass is 10% - 12%, the third pass is 8% - 10%, and the reduction of the last rolling pass is not less than 20% of the total reduction; Optimized adjustment of head and tail thickness rolling impact compensation includes: Set a dynamic compensation coefficient in the rolling pass table, and the compensation range is the head and tail 5-meter section; According to the real-time feedback of the target value of the second-opening temperature, adjust the compensation amplitude to ±0.5% - 1.0% of the thickness Post-rolling thickness measurement and feedback adjustment: The post-rolling thickness is measured by a high-precision ultrasonic thickness gauge. The measurement interval is to perform a full-section scan every 2 meters, and transmit the data to the control system in real time for program iteration optimization. Measure and record the thickness of the rolled steel plate, and dynamically adjust the rolling program according to the measured results to optimize the thickness accuracy.

[0012] Except for the above embodiments, the present invention may also have other implementation manners. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A control method for improving the thickness accuracy of cold controlled rolling thick plates, characterized in that, It includes the following steps: Optimizing the heating process: Set the heating temperature of the steel plate at 1040 - 1060 °C, extend the total time in the furnace to 10 - 12 hours, and increase the effective heating time to 4 - 5 hours. Among them, in the three-stage heating section, first heat up to 1080 °C, and in the soaking section, cool down to 1040 °C to ensure the temperature uniformity of the steel plate; Optimizing the rolling model: Cut a scientific research sample of the coefficient of thermal expansion from the low-temperature controlled-rolled steel plate after rolling. Measure the coefficient of thermal expansion every 25 °C in the range of 600 - 1000 °C. Revise the rolling program according to the measured data, and extract the target value of the second-opening temperature ≤ 780 °C, and transmit it to the level 1 system for optimized adjustment of the head and tail thickness rolling impact compensation; Arranging the rolling reduction schedule: Pre-arrange the torque of the schedule according to 7800. Ensure that the reduction rate of the last three passes in rough rolling is more than 10%, and maximize the reduction amount of the last pass; Measuring and feedback adjusting the thickness after rolling: Measure the thickness of the steel plate after rolling and record the data, and dynamically adjust the rolling program according to the measured results to optimize the thickness accuracy.

2. The control method for improving the thickness accuracy of a cold rolling thick plate according to claim 1, wherein: In the optimization of the heating process, the temperature fluctuation range in the soaking section is controlled within ±5 °C, and a segmented heating and cooling strategy is adopted to ensure uniform heating of the entire steel plate.

3. A control method for improving the thickness accuracy of cold tandem rolling thick plates according to claim 1, characterized in that: In the optimization of the rolling model, the laser scanning method is used to measure the coefficient of thermal expansion, and when revising the rolling program, the actual deformation resistance curve of the steel grade is combined to dynamically adjust the rolling force and torque parameters.

4. A control method for improving the thickness accuracy of cold controlled rolling thick plates according to claim 1, characterized in that: In the arrangement of the rolling reduction schedule, the reduction rates of the last three passes in rough rolling are specifically: the reduction rate of the first pass is 12% - 15%, the second pass is 10% - 12%, and the third pass is 8% - 10%, and the reduction amount of the last rolling pass is not less than 20% of the total reduction amount.

5. The control method for improving the thickness accuracy of cold controlled rolling thick plates according to claim 4, characterized in that, The optimized adjustment of the head and tail thickness rolling impact compensation includes: Set a dynamic compensation coefficient in the rolling pass table, and the compensation range is the 5-meter section at the head and tail; According to the real-time feedback of the target value of the second-opening temperature, adjust the compensation amplitude to ±0.5% - 1.0% of the thickness.

6. A control method for improving the thickness accuracy of a cold controlled rolling thick plate according to claim 1, characterized in that, For the thickness measurement after rolling, a high-precision ultrasonic thickness gauge is used, and the measurement interval is to perform a full-section scan every 2 meters, and the data is transmitted to the control system in real time for program iterative optimization.