A method for controlling uniform phase transformation of hot-rolled wide strip steel

Abstract

This invention relates to a method for controlling the uniform phase transformation of hot-rolled wide strip steel, belonging to the technical field of steel material processing control methods. The technical solution of this invention is as follows: Dynamic temperature detection is performed during the rolling and post-rolling cooling processes of hot-rolled strip steel. The phase transformation state of the hot-rolled strip steel is confirmed by combining phase transformation experimental analysis results. After coupled analysis, homogenization phase transformation control during finishing rolling and post-rolling homogenization phase transformation are implemented, forming a detection-analysis-control-re-detection uniform phase transformation cyclic adjustment control system. The beneficial effects of this invention are: it not only characterizes and analyzes the phase transformation of hot-rolled wide strip steel during production, but also allows for adjustment and control of the phase transformation uniformity at different locations within the strip steel.

Description

Technical Field

[0001] This invention relates to a method for controlling the uniform phase transformation of hot-rolled wide strip steel, belonging to the technical field of steel material processing control methods. Background Technology

[0002] Hot-rolled wide strip steel is an important steel material that has been widely used in industries such as automobiles, home appliances, and construction. Since the microstructure significantly affects the properties and shape of hot-rolled wide strip steel, previous studies have primarily focused on the uniformity of its microstructure and properties. However, there is a lack of methods for detecting, analyzing, and controlling the uniform phase transformation process in hot-rolled wide strip steel.

[0003] Chinese patent CN117165751B discloses a method for improving the uniformity of microstructure along the entire length of cold-rolled microalloyed high-strength steel. As the finishing mill exit temperature and coiling temperature decrease, the volume fraction of ferrite and pearlite is increased, thus advancing the overall phase transformation process. At the same time, by adding a coil hanging process, the outer ring of the steel coil is allowed to cool for a longer period of time before uncoiling, effectively alleviating the uneven distribution of microstructure along the entire length of the cold-rolled microalloyed high-strength steel coil.

[0004] Chinese Patent Publication No. CN113626989A discloses a method for determining the waviness threshold considering the effects of temperature and phase transformation inhomogeneity. The method uses experimental regression to quantify the distribution of the material tangential modulus along the width direction of the strip under the influence of transverse temperature and microstructure differences, thereby obtaining a distribution function of the material transverse tangential modulus considering the effects of temperature and phase transformation. Based on the distribution function, a waviness threshold model based on the small displacement theory of elastic thin plates is established and solved using the energy method to obtain the material waviness threshold considering the effects of temperature and phase transformation.

[0005] The aforementioned patent controls the microstructure and phase transformation uniformity of strip steel through temperature process control and model analysis. Process control is a necessary control method for all hot-rolled wide strip steel, which can determine the target quality of the product. However, it cannot perform special control on areas such as the head, tail and edges of the strip steel. It can only ensure that the hot rolling process can be fully successful by widening the process window. Summary of the Invention

[0006] The purpose of this invention is to provide a method for controlling the uniform phase transformation of hot-rolled wide strip steel. This method involves dynamically acquiring and performing two-dimensional numerical characterization of strip temperature data at different locations between finishing mill stands and during laminar cooling. This data is then coupled with the phase transformation law of hot-rolled wide strip steel to characterize the uniformity of phase transformation at various locations during rolling and post-rolling cooling, thus providing a basis for effective and precise control of hot-rolled wide strip steel. Multiple control methods are used to intervene in non-uniform phase transformation regions, reducing asynchronous phase transformation. Through a process of dynamic detection, coupled analysis, precise control, and cyclic detection, multiple closed-loop control cycles are achieved, ultimately realizing effective control of the uniform phase transformation of hot-rolled wide strip steel and effectively solving the aforementioned problems in the background technology.

[0007] The technical solution of this invention is: a method for controlling uniform phase transformation of hot-rolled wide strip steel, comprising the following steps: S11: Dynamic temperature detection and temperature verification. Dynamic temperature detection of hot-rolled wide strip steel is carried out between F1 and F7 finishing mills, at the F7 exit, and at the laminar cooling position. Temperature data matrices of strip steel at the F1 to F7 exits and in laminar cooling are obtained. The transverse / longitudinal temperature curves of the strip steel are plotted using the temperature data to characterize the temperature state and uniformity distribution of the strip steel at different positions. At the same time, the temperature data of the finishing mill exit of the hot rolling production line is verified with the dynamic data of the F7 exit, and the temperature deviation is controlled within ±0.5%. S12: Coupled phase transformation analysis at different temperatures and deformation percentages. Based on the phase transformation simulation experiment results, the critical phase transformation temperature at different deformation percentages is coupled and analyzed. A phase transformation coupled analysis diagram of hot-rolled wide strip steel at different cooling rates and different deformation percentages is drawn. Combined with the rolling control model, it is analyzed whether each position of the strip steel is in the phase transformation range during the finishing rolling process, and it is determined whether phase transformation has occurred at each position of the strip steel. S1: Homogenization phase transformation control in finishing rolling. Based on the coupled analysis results of steps S11 and S12, and combined with the rolling control model, the temperature and homogeneous phase transformation of hot-rolled strip steel during rolling are accurately characterized and controlled by adjusting the cooling water spraying time between stands and closing the edge cooling measures. S2: Post-rolling homogenization phase transformation control, combined with layer cooling, edge and slow cooling control methods, to achieve characterization and control of the post-rolling cooling process, and finally achieve uniform phase transformation of hot-rolled wide strip steel; S3: Verify the effect of dynamic temperature detection and homogenization phase transformation control. Repeat step S11 to verify the effect of homogenization phase transformation control on hot-rolled wide strip steel. At the same time, collect the adjusted temperature uniformity data and feed it back to step S12 to complete the closed-loop control.

[0008] In step S11, the hot-rolled wide strip steel is subjected to two-dimensional planar temperature acquisition in the transverse and longitudinal directions during the finishing mill stand and the layer cooling process, thereby forming a temperature data matrix (Tx11, Tx12, ..., Tx1n, Tx21, ..., Txij, ..., Txmn) to provide a more comprehensive characterization of the head, tail and edge positions of the hot-rolled wide strip steel.

[0009] In step S12, the coupled model formula for the critical phase transition temperature Tr can be characterized as: Tr=Tc(C,Si,Mn,……)+Tε(ε,Td)+Tv(v,ε) where Tr is the critical phase transition temperature; Tc is the influencing factor of chemical composition; Tε is the influence of deformation percentage ε and deformation temperature Td; and Tv is the influence of cooling rate on phase transition. Based on production requirements, Tr-ε-v phase transformation analysis diagrams for steels with different chemical compositions are established and coupled with the temperature data collected in step S11 for analysis. （x） =ΣTx mn - Tr, via f （x） A threshold value greater than 0 is used to determine the phase transformation state during the rolling and post-rolling cooling process of hot-rolled wide strip steel, and to characterize the phase transformation state at different locations of the hot-rolled wide strip steel.

[0010] In step S3, step S11 is repeated to verify the effectiveness of steps S1 and S2, where ΔTx = |ΣTx mn -ΣTx ij The temperature data matrix of each group is compared. If the temperature deviation decreases, it indicates that the control method is effective. The collected and adjusted temperature uniformity data is re-coupled with the Tr-ε-v phase transformation analysis diagram. After multiple iterations of optimization, the effective control of uniform phase transformation of hot-rolled wide strip steel is finally achieved.

[0011] The beneficial effects of this invention are as follows: By dynamically acquiring and two-dimensionally characterizing the strip temperature data at different locations between finishing mill stands and during laminar cooling, and coupling this data with the phase transformation law of hot-rolled wide strip steel, the uniformity of phase transformation at various locations of hot-rolled wide strip steel during rolling and post-rolling cooling can be characterized, thus providing a basis for effective and precise control of hot-rolled wide strip steel; by intervening in non-uniform phase transformation regions through multiple control methods, the asynchronous phase transformation situation can be reduced; through a process of dynamic detection-coupling analysis-precise control-cyclic detection, multiple cycles of closed-loop control are achieved, ultimately realizing effective control of uniform phase transformation of hot-rolled wide strip steel. Attached Figure Description

[0012] Figure 1 This is a block diagram of the control system structure of the present invention; Figures 2 to 8 This is a graph showing the temperature data collection and analysis at different locations of the hot-rolled strip during the rolling process, as described in an embodiment of the present invention. Figure 9 This is a data acquisition diagram of the post-rolling cooling temperature in an embodiment of the present invention; Figure 10 This is a graph showing the post-rolling cooling temperature data analysis of an embodiment of the present invention. Figure 11 This is a Tr-ε-v phase transition analysis diagram from an embodiment of the present invention; Figure 12 This is a metallographic image of the middle position of the hot-rolled wide strip steel in an embodiment of the present invention; Figure 13 Metallographic image of the edge position of hot-rolled wide strip steel according to an embodiment of the present invention; Figure 14 This is a scanning electron microscope image of the middle position of a hot-rolled wide strip steel according to an embodiment of the present invention; Figure 15 This is a scanning electron microscope (SEM) image of the edge position of a hot-rolled wide strip steel according to an embodiment of the present invention. Figure 16 This diagram illustrates the effective control measures for uniform phase transition in an embodiment of the present invention. Figure 17 This is a diagram showing the temperature data acquisition of the back layer of the closed-loop control system according to an embodiment of the present invention. Figure 18 This is a graph showing the temperature data analysis of the back-end cooling layer after closed-loop control in an embodiment of the present invention. Figure 19 This is a metallographic image of the intermediate position after closed-loop control in an embodiment of the present invention. Figure 20 Metallographic image of the rear edge position of the closed-loop control in an embodiment of the present invention; Figure 21 This is a scanning electron microscope image of the intermediate position after closed-loop control in an embodiment of the present invention. Figure 22 This is a scanning electron microscope image of the rear edge position of the closed-loop control in an embodiment of the present invention; Figure 23 This is a diagram showing the plate shape and quality before the implementation of the control method in this embodiment of the invention. Figure 24 This is a diagram showing the plate shape and quality after the control method of this invention has been implemented. In the diagram: pearlite a, ferrite b, bainite c. Detailed Implementation

[0013] To make the purpose, technical solutions, and advantages of the invention's embodiments clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only a small part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0014] A method for controlling uniform phase transformation in hot-rolled wide strip steel includes the following steps: S11: Dynamic temperature detection and temperature verification. Dynamic temperature detection of hot-rolled wide strip steel is carried out between F1 and F7 finishing mills, at the F7 exit, and at the laminar cooling position. Temperature data matrices of strip steel at the F1 to F7 exits and in laminar cooling are obtained. The transverse / longitudinal temperature curves of the strip steel are plotted using the temperature data to characterize the temperature state and uniformity distribution of the strip steel at different positions. At the same time, the temperature data of the finishing mill exit of the hot rolling production line is verified with the dynamic data of the F7 exit, and the temperature deviation is controlled within ±0.5%. S12: Coupled phase transformation analysis at different temperatures and deformation percentages. Based on the phase transformation simulation experiment results, the critical phase transformation temperature at different deformation percentages is coupled and analyzed. A phase transformation coupled analysis diagram of hot-rolled wide strip steel at different cooling rates and different deformation percentages is drawn. Combined with the rolling control model, it is analyzed whether each position of the strip steel is in the phase transformation range during the finishing rolling process, and it is determined whether phase transformation has occurred at each position of the strip steel. S1: Homogenization phase transformation control in finishing rolling. Based on the coupled analysis results of steps S11 and S12, and combined with the rolling control model, the temperature and homogeneous phase transformation of hot-rolled strip steel during rolling are accurately characterized and controlled by adjusting the cooling water spraying time between stands and closing the edge cooling measures. S2: Post-rolling homogenization phase transformation control, combined with layer cooling, edge and slow cooling control methods, to achieve characterization and control of the post-rolling cooling process, and finally achieve uniform phase transformation of hot-rolled wide strip steel; S3: Verify the effect of dynamic temperature detection and homogenization phase transformation control. Repeat step S11 to verify the effect of homogenization phase transformation control on hot-rolled wide strip steel. At the same time, collect the adjusted temperature uniformity data and feed it back to step S12 to complete the closed-loop control.

[0015] In step S11, the hot-rolled wide strip steel is subjected to two-dimensional planar temperature acquisition in the transverse and longitudinal directions during the finishing mill stand and the layer cooling process, thereby forming a temperature data matrix (Tx11, Tx12, ..., Tx1n, Tx21, ..., Txij, ..., Txmn) to provide a more comprehensive characterization of the head, tail and edge positions of the hot-rolled wide strip steel.

[0016] In step S12, the coupled model formula for the critical phase transition temperature Tr can be characterized as: Tr=Tc(C,Si,Mn,……)+Tε(ε,Td)+Tv(v,ε) where Tr is the critical phase transition temperature; Tc is the influencing factor of chemical composition; Tε is the influence of deformation percentage ε and deformation temperature Td; and Tv is the influence of cooling rate on phase transition. Based on production requirements, Tr-ε-v phase transformation analysis diagrams for steels with different chemical compositions are established and coupled with the temperature data collected in step S11 for analysis. （x） =ΣTx mn- Tr, via f （x） A threshold value greater than 0 is used to determine the phase transformation state during the rolling and post-rolling cooling process of hot-rolled wide strip steel, and to characterize the phase transformation state at different locations of the hot-rolled wide strip steel.

[0017] In step S3, step S11 is repeated to verify the effectiveness of steps S1 and S2, where ΔTx = |ΣTx mn -ΣTx ij The temperature data matrix of each group is compared. If the temperature deviation decreases, it indicates that the control method is effective. The collected and adjusted temperature uniformity data is re-coupled with the Tr-ε-v phase transformation analysis diagram. After multiple iterations of optimization, the effective control of uniform phase transformation of hot-rolled wide strip steel is finally achieved.

[0018] In practical applications, the present invention includes the following steps: (1) Step S11: Dynamic temperature detection of hot-rolled wide strip steel is performed at locations such as the F1~F7 finishing mill, F7 exit, and laminar cooling to obtain the F1 exit temperature (T1). 11 T1 12 T1 13 ...T1 1n ...T1 mn F2 outlet temperature (T2) 11 T2 12 T2 13 ...T2 1n ...T2 mn ), F3 outlet temperature (T3) 11 T3 12 T3 13 ...T3 1n ...T3 mn F4 outlet temperature (T4) 11 T4 12 T4 13 ...T4 1n ...T4 mn F5 outlet temperature (T5) 11 T5 12 T5 13 ...T5 1n ...T5 mn ), F6 outlet temperature (T6) 11 T6 12 T6 13 ...T6 1n ...T6 mn ), F7 outlet temperature (T7) 11 T7 12 T7 13 ...T7 1n ...T7mn ), and the laminar cooling temperatures (TLx11, TL12, …… TL1n, TL21, …… TLij, …… TLmn), and use the temperature data to plot the two-dimensional temperature curve of the strip steel, so as to characterize the temperature state and uniformity distribution of the strip steel at different positions, and provide basic data for subsequent analysis of material phase transformation. At the same time, use the temperature measurement data of the finishing mill outlet of the hot rolling production line to check with the dynamic data at the F7 outlet, and control the temperature deviation within ±0.5%. If the temperature deviation exceeds, it is necessary to check the data acquisition system.

[0019] (2) Step S12, based on the results of the phase transformation simulation experiment, coupling and analyzing the critical phase transformation temperature Tr of different deformation percentages (ε), and its coupling model formula can be characterized as: Tr = Tc(C, Si, Mn, ……) + Tε(ε, Td) + Tv(v, ε), where: Tc is the influence factor of chemical composition; Tε is the influence of deformation percentage (ε) and deformation temperature (Td); Tv is the influence of cooling rate on phase transformation. Thus, plot the Tr-ε-v phase transformation analysis diagram of hot-rolled wide strip steel with different cooling rates and different deformation percentages. Combine with the rolling control model (K11), and conduct coupling analysis with the temperature data collected in step S11. f(x) = ΣTxmn - Tr, and through f(x) > 0 for threshold determination, it can be analyzed whether each position of the strip steel in the finishing process is in the phase transformation interval, so as to determine whether phase transformation has occurred at each position of the strip steel, confirm the phase transformation state of different positions of the hot-rolled wide strip steel, realize the characterization of the phase transformation state of different positions of the hot-rolled wide strip steel, and provide a basis for subsequent adjustment control.

[0020] (3) Steps S1 and S2, effectively control the temperature uniformity of the hot-rolled wide strip steel, so as to provide effective adjustment for uniform phase transformation. S1 combines with the rolling control model, and by adjusting the water spraying time between stands and closing the edge cooling and other measures, it can achieve accurate characterization and control of the temperature and uniform phase transformation of the hot-rolled strip steel during the rolling process; S2 combines with laminar cooling, edge and slow cooling control means, and can achieve characterization and control during the post-rolling cooling process.

[0021] (4) Loop step S11 to verify the control effect of the uniform phase transformation of the hot-rolled wide strip steel. ΔTx = 丨ΣTxmn - ΣTxij 丨, compare each group of temperature data matrices. If the temperature deviation decreases, it means that the control method is effective.

[0022] (5) Loop step S12, re-couple and analyze the temperature uniformity data collected and adjusted in step (4) with the Tr-ε-v phase transformation analysis diagram. After multiple loop optimizations, the effective control of the uniform phase transformation of the hot-rolled wide strip steel can be achieved.

[0023] (6) Repeat steps S1 and S2 to perform more precise uniform phase change control adjustment and complete closed-loop control. Example

[0024] A certain factory's 780MPa grade hot-rolled high-strength wide strip steel exhibited severe edge waviness and performance fluctuations during production. Inspection of the finished strip revealed significant differences in microstructure between the central and edge areas, indicating inhomogeneous phase transformation at different transverse locations, which was the primary cause of the waviness and performance fluctuations. However, conventional testing methods only allow for temperature monitoring at the finishing mill exit and coiling entrance, and only for metallographic analysis of hot-rolled finished products, failing to characterize the rolling and post-rolling processes. Therefore, this invention was innovatively designed to solve the aforementioned problems.

[0025] The chemical composition of hot-rolled wide strip steel is as follows: C: 0.11~0.15%, Si: 0.60~0.80%, Mn: 2.0~2.2%, P: <0.020%, S: 0.010%, Nb: 0.010~0.030, Ti: 0.015~0.030.

[0026] First, such as Figure 1 Step S11 involves dynamically acquiring temperature data for the hot-rolled wide strip steel, obtaining temperature data at different locations on the hot-rolled strip steel, and plotting temperature curves according to analysis requirements, such as... Figures 2 to 8 Analysis revealed a temperature difference of approximately 50°C between the head and tail of the strip, with a temperature drop of about 30-60°C at the strip edges. Most importantly, systematic analysis showed a significant temperature decrease on the operating side of the strip after F3; after F6, the temperature on the drive side was significantly higher than the operating side, with a temperature deviation exceeding 40°C, indicating a serious anomaly in the cooling system between F3-F4 and F6-F7. Figure 9 and Figure 10 This can intuitively characterize the temperature uniformity of hot-rolled wide strip steel during the layer cooling process. It was found that the strip steel not only has a serious head-to-tail temperature difference problem, but also a serious transverse temperature difference. Moreover, the transverse temperature difference at the head and tail is in opposite directions, indicating that there is a serious process control problem in the layer cooling process.

[0027] Then, in step S12, based on the results of the thermal simulation phase transformation test under different deformation amounts, a Tr-ε-v phase transformation analysis diagram is plotted. Since the phase transformation temperature is related to factors such as the chemical composition of the steel material, the deformation percentage, and the cooling rate, the critical phase transformation temperature can be characterized by the formula Tr=Tc(C,Si,Mn,……)+Tε(ε,Td)+Tv(v,ε). The Tr-ε-v phase transformation analysis diagram in this embodiment is as follows. Figure 11Coupled analysis with the temperature data collected in step S11 revealed that although there was temperature drop at the beginning, end, and edges during the rolling process, the overall temperature remained above 850℃, not yet entering the phase transformation temperature range, and therefore no phase transformation occurred. The laminar cooling process, however, is more complex. Based on thermal simulation phase transformation experiments, the critical phase transformation temperature Tr is around 575℃. Figure 9 and Figure 10 As shown, during laminar cooling, different locations on the hot-rolled wide strip are within different ranges of the phase transformation temperature. No phase transformation occurs above Tr, while phase transformation does occur below Tr, ultimately leading to asynchronous phase transformation at different locations on the strip, and even severe non-uniform phase transformation in the transverse direction. This result is consistent with the microstructure analysis results of hot-rolled products, such as... Figures 12 to 15 As shown, the temperature at the middle position is above Tr, and no bainitic phase transformation occurs during the laminar cooling process. After coiling, the temperature is slowly reduced, and the final microstructure is ferrite + pearlite. However, the temperature at the edge position is below Tr, and a bainitic phase transformation occurs during the laminar cooling process after rolling, resulting in a microstructure of bainite + ferrite. This leads to uneven phase transformation at different locations in the material, resulting in significant differences in the coefficient of thermal expansion and internal stress, causing waviness and performance fluctuations in hot-rolled wide strip steel. This invention can provide a detailed explanation of the causes and mechanisms of the above problems. Furthermore, based on the data obtained from the coupling analysis, specific locations requiring control and adjustment can be identified, such as the cooling water between stands F3~F4 and F6~F7, and the opening time of the laminar cooling side spray.

[0028] Following the above coupling analysis, a targeted control scheme can be formulated to effectively control the temperature uniformity of hot-rolled wide strip steel by executing steps S1 and S2. On-site inspection revealed severe blockage of the cooling water between stands F5 and F6, leading to significant cooling unevenness, consistent with the coupling analysis data. Measures such as closing the edge cooling water nozzles to reduce edge temperature drop were implemented. The uneven temperature at the beginning and end of the tiered cooling system was mainly caused by abnormal cooling water opening time and side spray pressure, also consistent with the coupling analysis curve. The aforementioned measures were implemented as follows: Figure 16 As shown. According to the uniform phase transformation method provided by this invention, the uniformity of phase transformation during the rolling and post-rolling cooling process of hot-rolled wide strip steel is characterized, and the abnormal positions are accurately located, thus achieving effective control of homogenization.

[0029] Steps S11 and S12 were repeated to verify the uniform phase transformation control effect of the hot-rolled wide strip steel. The head-tail and transverse temperature deviation ΔTx was reduced from 80℃ to 25℃, and the overall strip temperature was controlled above Tr (575℃). This ensured that the hot-rolled wide strip steel was in a synchronous phase transformation state during rolling and post-rolling cooling, i.e., the pearlite phase transformation occurred synchronously after coiling, avoiding premature entry into the bainite phase transformation range due to excessively low edge and head-tail temperatures or excessively rapid cooling rates. Temperature data collected during step S11 can be found... Figure 17 and Figure 18 As shown, the temperature difference between the head and tail and the lateral side has been controlled within 25℃, and ΔTx has been significantly improved.

[0030] Repeat steps S1 and S2 to perform fine-tuning control, and then perform metallographic analysis on the optimized product. Figures 19 to 22 As shown, the microstructure in the middle and edge positions was confirmed to be entirely ferrite + pearlite, with no bainite structure present. This verifies that the strip microstructure did not enter the bainite phase transformation range, which corroborates the analysis results of this patent, ultimately achieving uniform phase transformation control of hot-rolled wide strip steel. Furthermore, after implementing the control method of this invention, the overall double-sided waviness of the hot-rolled wide strip steel was significantly improved, and the strip shape quality was effectively controlled.

[0031] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for controlling uniform phase transformation in hot-rolled wide strip steel, characterized in that... Includes the following steps: S11: Dynamic temperature detection and temperature verification. Dynamic temperature detection of hot-rolled wide strip steel is carried out between F1 and F7 finishing mills, at the F7 exit, and at the laminar cooling position. Temperature data matrices of strip steel at the F1 to F7 exits and in laminar cooling are obtained. The transverse / longitudinal temperature curves of the strip steel are plotted using the temperature data to characterize the temperature state and uniformity distribution of the strip steel at different positions. At the same time, the temperature data of the finishing mill exit of the hot rolling production line is verified with the dynamic data of the F7 exit, and the temperature deviation is controlled within ±0.5%. S12: Coupled phase transformation analysis at different temperatures and deformation percentages. Based on the phase transformation simulation experiment results, the critical phase transformation temperature at different deformation percentages is coupled and analyzed. A phase transformation coupled analysis diagram of hot-rolled wide strip steel at different cooling rates and different deformation percentages is drawn. Combined with the rolling control model, it is analyzed whether each position of the strip steel is in the phase transformation range during the finishing rolling process, and it is determined whether phase transformation has occurred at each position of the strip steel. S1: Homogenization phase transformation control in finishing rolling. Based on the coupled analysis results of steps S11 and S12, and combined with the rolling control model, the temperature and homogeneous phase transformation of hot-rolled strip steel during rolling are accurately characterized and controlled by adjusting the cooling water spraying time between stands and closing the edge cooling measures. S2: Post-rolling homogenization phase transformation control, combined with layer cooling, edge and slow cooling control methods, to achieve characterization and control of the post-rolling cooling process, and finally achieve uniform phase transformation of hot-rolled wide strip steel; S3: Verify the effect of dynamic temperature detection and homogenization phase transformation control. Repeat step S11 to verify the effect of homogenization phase transformation control on hot-rolled wide strip steel. At the same time, collect the adjusted temperature uniformity data and feed it back to step S12 to complete the closed-loop control.

2. The method for controlling uniform phase transformation of hot-rolled wide strip steel according to claim 1, characterized in that: In step S11, the hot-rolled wide strip steel is subjected to two-dimensional planar temperature acquisition in the transverse and longitudinal directions during the finishing mill stand and the layer cooling process, thereby forming a temperature data matrix of Tx11, Tx12, ..., Tx1n, Tx21, ..., Txij, ..., Txmn, which provides a more comprehensive characterization of the head, tail and edge positions of the hot-rolled wide strip steel.

3. The method for controlling uniform phase transformation of hot-rolled wide strip steel according to claim 1, characterized in that: In step S12, the coupled model formula for the critical phase transition temperature Tr can be characterized as: Tr=Tc(C,Si,Mn,……)+Tε(ε,Td)+Tv(v,ε) where Tr is the critical phase transition temperature; Tc is the influencing factor of chemical composition; Tε is the influence of deformation percentage ε and deformation temperature Td; and Tv is the influence of cooling rate on phase transition. Based on production requirements, Tr-ε-v phase transformation analysis diagrams for steels with different chemical compositions are established and coupled with the temperature data collected in step S11 for analysis. （x） =ΣTx mn - Tr, via f （x） A threshold value greater than 0 is used to determine the phase transformation state during the rolling and post-rolling cooling process of hot-rolled wide strip steel, and to characterize the phase transformation state at different locations of the hot-rolled wide strip steel.

4. The method for controlling uniform phase transformation of hot-rolled wide strip steel according to claim 1, characterized in that: In the step S3, the step S11 is looped to verify the implementation effects of the steps S1 and S2. ΔTx = 丨ΣTx mn -ΣTx ij 丨. Each group of temperature data matrices is compared. If the temperature deviation decreases, it indicates that the control method is effective. The collected and adjusted temperature uniformity data is recoupled and analyzed with the Tr-ε-v phase transformation analysis diagram. After multiple loop optimizations, the effective control of uniform phase transformation of hot-rolled wide strip steel is finally achieved.

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