A single roll large reduction model and control method

Abstract

The present application relates to a kind of single roll large reduction model and control method, belong to metallurgical continuous casting equipment and method technical field.The technical scheme of the present application is: integrated DynaPhase dynamic phase model, Dynacs 3D dynamic secondary cooling model and DynaGap Soft Reduction 3D dynamic soft reduction model, real-time calculation billet temperature field and solidification state, accurately determine the position of solidification end, and based on this control SRD sector segment implementation single roll large reduction operation.The beneficial effects of the present application are: by accurately predicting the solidification state of billet, intelligent control SRD sector segment implementation single roll large reduction, effectively improve the internal quality of billet, especially reduce center segregation and loose defect.

Description

Technical Field

[0001] This invention relates to a single-roller high-pressure model and control method, belonging to the technical field of metallurgical continuous casting equipment and methods. Background Technology

[0002] With the rapid development of high-end equipment manufacturing, marine engineering, nuclear power facilities, and other fields, the demand for high-quality thick plates is increasing. As a key link in steel production, the internal quality of continuous casting billets directly affects the performance of the final product. Traditional continuous casting billets commonly suffer from internal defects such as central porosity and central segregation, which severely restricts the development and application of high-end thick plate products.

[0003] Currently, the main technologies for improving the internal quality of cast slabs include dynamic light reduction and electromagnetic stirring. However, these technologies have limited effectiveness for thick slabs exceeding 300mm in thickness, primarily because the shell of thick slabs is thick, making it difficult for traditional technologies to effectively reach the central area of ​​the slab. To address this issue, various end-solidation heavy reduction technologies have been developed both domestically and internationally, such as Sumitomo Metal's PCCS technology, Nippon Steel's NS Bloom Large Reduction technology, and POSCO's PosHARP technology. However, most of these technologies employ a multi-roll, small reduction mode, with single-roll reduction typically less than 3mm, making it difficult for deformation to penetrate to the core of the slab, and the maximum slab thickness applied is usually no more than 300mm.

[0004] Primetals Technologies' SRD (Single Roll Dynamic Reduction) sector technology represents a significant advancement in this field. Specifically developed for use in the final solidification zone, the SRD sector allows the upper roll to press individually onto the solidifying cast stream, precisely executing the final solidification point reduction operation. This technology has been successfully applied to multiple continuous casting machines worldwide, including the 10-strand small billet continuous casting machine upgraded for Zhongtian Steel, and the newly built ultra-thick slab continuous casting machine for Wugang.

[0005] However, existing SRD technology still faces the following challenges in practical applications: (1) lack of accurate solidification end position prediction model, resulting in inaccurate pressing position; (2) poor matching between pressing parameters and billet solidification state, affecting pressing effect; (3) insufficient process adaptability for different steel grades and cross-sectional specifications. Therefore, developing a model system that can accurately control single-roll large pressing is of great significance for giving full play to the technical advantages of SRD sector segment and comprehensively improving the internal quality of billet. Summary of the Invention

[0006] The purpose of this invention is to provide a single-roller large reduction model and control method. By accurately predicting the solidification state of the billet, the SRD sector section is intelligently controlled to implement single-roller large reduction, which effectively improves the internal quality of the billet, especially reducing center segregation and porosity defects, and effectively solves the above-mentioned problems existing in the background art.

[0007] The technical solution of this invention is: a single-roller large reduction model, comprising an SRD sector segment unit, a process model calculation unit, and a dynamic control unit. The SRD sector segment unit is equipped with an upper roller, and the number of upper rollers is one or more, all of which are independently driven structures. The process model calculation unit includes a DynaPhase dynamic phase model, a Dynacs 3D dynamic secondary cooling model, and a DynaGapSoft Reduction 3D dynamic light reduction model. The DynaPhase dynamic phase model calculates the enthalpy, thermal conductivity, density, and solid phase ratio of the billet in real time. The Dynacs 3D dynamic secondary cooling model calculates the three-dimensional temperature distribution of the billet. The DynaGap SoftReduction 3D dynamic light reduction model determines the optimal reduction parameters. The input end of the dynamic control unit is connected to the output end of the process model calculation unit, and the output end of the dynamic control unit is connected to the SRD sector segment unit. Based on the calculation results of the process model, the reduction position and reduction force of each upper roller in the SRD sector segment are adjusted in real time to implement the single-roller large reduction operation.

[0008] In the SRD sector segment unit, each upper roller is equipped with a hydraulic control system and an overload protection device.

[0009] A method for controlling large reduction on a single roller includes the following steps: (1) Real-time acquisition of casting process parameters; (2) Calculate the temperature field and solidification state of the billet using a process model; (3) Determine the location of the solidification end and the optimal reduction range; (4) Control the single-roller large reduction of the SRD sector at the end of solidification; (5) Monitor the pressing effect and dynamically adjust the process parameters.

[0010] In step (3), the light pressing stage is when the solid fraction at the center of the billet is fs=0.1-0.85, and the single-roll heavy pressing stage is when fs=0.85-1.0.

[0011] In step (4), the single-roller large reduction operation is carried out in the range of 0.1-1.0 solid fraction fs at the center of the billet, and the single-roller reduction amount reaches 10-25mm.

[0012] In step (5), the gap between each roll is dynamically adjusted according to the steel grade, superheat, cooling intensity and pulling speed.

[0013] The beneficial effects of this invention are: by accurately predicting the solidification state of the billet and intelligently controlling the single-roll large reduction of the SRD sector, the internal quality of the billet is effectively improved, especially the central segregation and porosity defects are reduced. Detailed Implementation

[0014] To make the purpose, technical solutions, and advantages of the embodiments of the invention clearer, the technical solutions in the embodiments of the invention are described clearly and completely below. Obviously, the embodiments described are only a small part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without creative effort are within the protection scope of the invention.

[0015] A single-roller large reduction model includes an SRD sector segment unit, a process model calculation unit, and a dynamic control unit. The SRD sector segment unit has one or more upper rollers, each with an independent drive structure. The process model calculation unit includes a DynaPhase dynamic phase model, a Dynacs 3D dynamic secondary cooling model, and a DynaGap Soft Reduction 3D dynamic light reduction model. The DynaPhase dynamic phase model calculates the enthalpy, thermal conductivity, density, and solid phase ratio of the billet in real time. The Dynacs 3D dynamic secondary cooling model calculates the three-dimensional temperature distribution of the billet. The DynaGap Soft Reduction 3D dynamic light reduction model determines the optimal reduction parameters. The input of the dynamic control unit is connected to the output of the process model calculation unit, and the output of the dynamic control unit is connected to the SRD sector segment unit. Based on the process model calculation results, the reduction position and reduction force of each upper roller in the SRD sector segment are adjusted in real time to implement the single-roller large reduction operation.

[0016] In the SRD sector segment unit, each upper roller is equipped with a hydraulic control system and an overload protection device.

[0017] A method for controlling large reduction on a single roller includes the following steps: (1) Real-time acquisition of casting process parameters; (2) Calculate the temperature field and solidification state of the billet using a process model; (3) Determine the location of the solidification end and the optimal reduction range; (4) Control the single-roller large reduction of the SRD sector at the end of solidification; (5) Monitor the pressing effect and dynamically adjust the process parameters.

[0018] In step (3), the light pressing stage is when the solid fraction at the center of the billet is fs=0.1-0.85, and the single-roll heavy pressing stage is when fs=0.85-1.0.

[0019] In step (4), the single-roller large reduction operation is carried out in the range of 0.1-1.0 solid fraction fs at the center of the billet, and the single-roller reduction amount reaches 10-25mm.

[0020] In step (5), the gap between each roll is dynamically adjusted according to the steel grade, superheat, cooling intensity and pulling speed.

[0021] In practical applications, the core technical features of the SRD sector segment single-roller large reduction model of this invention are: Model system integration: DynaPhase + Dynacs 3D + DynaGap Soft Reduction 3D Compressive force range: 4000-5000 kN Solid fraction within the compression range: 0.1-1.0 Reduction range: 8-16mm for light reduction, 10-25mm for heavy reduction on a single roller Control method: Fully automatic dynamic control, supporting unsteady-state casting. Applicable billet thickness: 370mm to 460mm ultra-thick slabs Quality improvement effect: central porosity reduced by >50%, central segregation level ≤1.0. Innovation Model system integration innovation: For the first time, the DynaPhase dynamic phase model, Dynacs 3D dynamic secondary cooling model and DynaGap Soft Reduction 3D dynamic light reduction model are deeply integrated to form a complete single-roller large reduction control system, realizing precise control of the entire process from solidification state prediction to reduction parameter optimization.

[0022] Precise determination of the reduction range: The reduction range is determined based on the solid fraction fs at the center of the billet. The light reduction stage is set in the range of fs=0.1-0.85, and the single-roll heavy reduction stage is set in the range of fs≥0.85 to complete solidification, which conforms to the solidification law of the billet and maximizes the reduction effect.

[0023] Dynamic adaptive control: A dynamic control algorithm was developed that can adapt to changes in steel grade, superheat, cooling intensity and casting speed, to achieve stable pressing under unsteady casting conditions, with billet stagnation time of less than 7 minutes and billet surface temperature fluctuation controlled within ±25℃.

[0024] Multi-functional pressing mode: It integrates multiple pressing modes such as light pressing, heavy pressing and flexible pressing, and can intelligently select pressing strategies according to different steel grades and quality requirements, thereby improving process flexibility.

[0025] The process model system of this invention consists of three core models: 1. DynaPhase dynamic phase model Based on the principle of online thermodynamic phase transformation, the billet's properties are calculated in real time: Enthalpy change curve, Thermal conductivity changes with temperature The relationship between density and phase transition, The solid fraction distribution fs, especially the central solid fraction, This model provides key parameters for determining the reduction range, ensuring that the reduction operation is carried out under suitable solidification conditions.

[0026] Dynacs 3D Dynamic Dual-Cold Model The three-dimensional finite difference method is used to calculate the complete temperature field of the billet in the drawing direction, width direction, and thickness direction. Its features include: Under unsteady casting conditions, the billet retention time is less than 7 minutes. The surface temperature fluctuation of the cast billet is controlled within ±25℃. Accurately determine the final solidification point location with an error of less than ±100mm. A dual-target temperature control strategy is adopted, with target temperatures set separately for the center and the perimeter.

[0027] 3. DynaGap Soft Reduction 3D Dynamic Light Pressure Model Based on the temperature field and solidification state of the cast billet, the optimal reduction parameters are determined as follows: Initial position of compression: The position of the central solid fraction corresponding to the formation of V-shaped segregation; End of compression position: The position of the central solid fraction corresponding to the formation of island segregation; Reduction amount distribution: The reduction amount of each roller is dynamically distributed according to the shape of the solidification front; Optimized compression rate: to prevent internal crack formation; The three models interact in real time via a data bus, forming a closed-loop control system. The system updates the calculation results every 5 seconds to ensure that the compression parameters match the actual solidification state.

[0028] The single-roller large reduction control method includes the following specific steps: Step 1: Process parameter acquisition and preprocessing Collect real-time data such as casting speed, steel grade, superheat, crystallizer cooling water volume, and secondary cooling zone water volume; Data filtering is performed to eliminate measurement noise. Standardize parameters and unify data formats and units.

[0029] Step 2: Calculation of the solidification state of the billet Call the DynaPhase model to calculate the thermal properties of the billet under the current operating conditions; Run the Dynacs 3D model to calculate the three-dimensional temperature distribution of the cast billet; Determine the shape of the solidification front and the location of the final solidification point; Calculate the distribution curve of the solid fraction fs at the center of the billet along the billet pulling direction.

[0030] Step 3: Determine the compression range and parameters Determine the reduction strategy based on the solid fraction fs at the center of the billet: When 0≤fs<0.85: Implement multi-roller light pressing, with a total pressing amount of 8-16mm, distributed to multiple rollers; When fs≥0.85: Implement single-roll large reduction on the first and first two rolls corresponding to the complete solidification point, with a reduction of 10-25mm; For fully solidified billets: after the point of complete solidification, a single roll is subjected to large pressure to further reduce central porosity.

[0031] Step 4: SRD sector segment compression control The calculated compression parameters are sent to the SRD sector controller; Each upper roller adjusts its position and pressing force independently according to instructions; A "delayed pressing position" control strategy is adopted: adjustment only begins when the pressing position change exceeds 200mm, reducing the impact of instantaneous fluctuations in pulling speed on pressing. Monitor roll gap and pressing force in real time to ensure they match the set values.

[0032] Step 5: Evaluation and Feedback Optimization of Pressurization Effect Online monitoring of surface temperature changes in the cast billet; Regularly sample and analyze the internal quality of the cast billet (central porosity, segregation, etc.); Optimize model parameters based on quality inspection results; Establish a database of pressing processes for different steel grades and specifications. Implementation effect

[0033] The center porosity rating is reduced from 2.5-3.0 in the traditional process to 1.0-1.5; the center segregation index is reduced from 1.15 to 0.95; the rolling compression ratio can be reduced from the traditional ≥3.0 to 1.5-2.5; the yield is increased by 15-25%, and energy consumption and cost are reduced by more than 50%.

[0034] Model system composition and data flow To better understand the collaborative relationships among the various model systems in this invention, the following is a detailed description of the system composition and data flow: Core model system composition DynaPhase dynamic phase model Main function: Real-time thermodynamic calculation Key output parameters: enthalpy, thermal conductivity, density, solidity (core: central solidity fs) Data flow: Providing the material property basis for Dynacs 3D models Dynacs 3D Dynamic Dual-Cold Model Main function: Three-dimensional temperature field simulation Key output parameters: three-dimensional temperature distribution of the billet, position of the solidification front, and final solidification point. Data flow: Providing solidification state input for the DynaGap model DynaGap Soft Reduction 3D Model Main function: Optimization of pressing process Key output parameters: optimal pressing range, pressing amount / force distribution of each roller, pressing speed Data flow direction: Output control commands to the SRD sector segment actuator. Auxiliary and Execution Systems Data acquisition and preprocessing module Main function: Real-time acquisition of process parameters Key output parameters: drawing speed after cleaning, steel grade, superheat, and cooling data. Data flow: Provides real-time operating condition input for the three core models. SRD sector execution unit Main function: Physically perform the pressing operation Key output parameters: actual roll gap, pressure feedback Data flow: Receives DynaGap commands and feeds back execution data for closed-loop control. Quality Feedback and Model Self-Learning Module Main functions: effect evaluation and parameter optimization Key output parameters: model parameter correction values, process optimization suggestions Data flow: Based on product quality inspection results, the core model parameters are optimized in reverse. System data flow description: The data acquisition module synchronously provides real-time process parameters to the DynaPhase and Dynacs3D models. The calculation results (material properties) of DynaPhase serve as one of the inputs to Dynacs3D, and together they output an accurate solidification state of the cast billet to the DynaGap model. Based on this, the DynaGap model calculates the optimal reduction process parameters and sends them to the SRD sector for execution.

[0035] Compared with the prior art, the present invention has the following significant advantages: 1. Significantly improves the internal quality of the cast billet: By precisely controlling the large single-roll reduction at the end of solidification, it effectively compensates for the solidification shrinkage of the cast billet, eliminates central shrinkage cavities, and reduces central segregation and porosity. Applications show that central porosity can be reduced by more than 50%, and the level of central segregation can be controlled within 1.0.

[0036] 2. Expanding the range of continuous casting billet thickness: The maximum applicable billet thickness of traditional solidification end-reduction technology is generally no more than 300mm, while this invention, combined with the high pressure reduction of the SRD fan-shaped section, can be successfully applied to the continuous casting production of ultra-thick slabs with a thickness of up to 460mm.

[0037] 3. Reduce rolling compression ratio requirements: By improving the internal density of the billet, the rolling compression ratio required for producing extra-thick plates can be reduced from the traditional ≥3.0 to 1.5-2.5, reducing the number of rolling passes and energy consumption.

[0038] 4. Improve production efficiency and yield: Replace some of the die casting and vacuum composite welding processes, shorten the production process, increase the yield by 15-25%, and reduce energy consumption and costs by more than 50%.

[0039] 5. Enhanced process adaptability: Integrates multiple pressing modes, and can intelligently select pressing strategies according to different steel grades, cross-sectional specifications and quality requirements, thereby improving the flexibility of the production line.

[0040] 6. Achieve fully automatic dynamic control: Based on an advanced process model, the pressing parameters and casting conditions are matched in real time, reducing manual intervention and improving control accuracy and stability.

[0041] 7. Extend equipment life: The SRD sector adopts a modular design and overload protection device, which makes maintenance convenient, has a long service life, and can significantly reduce maintenance costs.

[0042] This invention is applicable to continuous casting machines with a thickness of 370-460mm and a cross-sectional specification of 1600-2500mm. The applicable steel grades cover low carbon steel, medium carbon steel, high carbon steel, as well as alloy steel, spring steel, cord steel, pipeline steel, offshore wind power steel, nuclear power steel and other high-quality steel grades.

[0043] This invention has been successfully applied to the continuous casting machine of Wugang Steel, and the high-quality cast billets produced are used in high-end equipment such as wind turbine towers, large tunnel boring machines, and 10,000-ton ocean-going transport ships.

[0044] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A single-roller large-reduction model, characterized in that: The system comprises an SRD sector segment unit, a process model calculation unit, and a dynamic control unit. Each SRD sector segment unit has one or more upper rollers, all with independent drive structures. The process model calculation unit includes a DynaPhase dynamic phase model, a Dynacs 3D dynamic secondary cooling model, and a DynaGap SoftReduction 3D dynamic light reduction model. The DynaPhase dynamic phase model calculates the enthalpy, thermal conductivity, density, and solid phase ratio of the billet in real time. The Dynacs 3D dynamic secondary cooling model calculates the three-dimensional temperature distribution of the billet. The DynaGap Soft Reduction 3D dynamic light reduction model determines the optimal reduction parameters. The input of the dynamic control unit is connected to the output of the process model calculation unit, and the output of the dynamic control unit is connected to the SRD sector segment unit. Based on the process model calculation results, the dynamic control unit adjusts the reduction position and force of each upper roller in the SRD sector segment in real time to implement single-roller large reduction operation.

2. The single-roller large-reduction model according to claim 1, characterized in that: In the SRD sector segment unit, each upper roller is equipped with a hydraulic control system and an overload protection device.

3. A method for controlling large reduction in pressure on a single roller, characterized in that... Includes the following steps: (1) Real-time acquisition of casting process parameters; (2) Calculate the temperature field and solidification state of the billet using a process model; (3) Determine the location of the solidification end and the optimal reduction range; (4) Control the single-roller large reduction of the SRD sector at the end of solidification; (5) Monitor the pressing effect and dynamically adjust the process parameters.

4. The single-roller large reduction control method according to claim 3, characterized in that: In step (3), the light pressing stage is when the solid fraction at the center of the billet is fs=0.1-0.85, and the single-roll heavy pressing stage is when fs=0.85-1.

0.

5. The single-roller large reduction control method according to claim 3, characterized in that: In step (4), the single-roller large reduction operation is carried out in the range of 0.1-1.0 solid fraction fs at the center of the billet, and the single-roller reduction amount reaches 10-25mm.

6. The single-roller large reduction control method according to claim 3, characterized in that: In step (5), the gap between each roll is dynamically adjusted according to the steel grade, superheat, cooling intensity and pulling speed.