The strip flatness and crown control model is the foundation of automatic strip shape control. Considering the metal transverse flows and the inter stand second deformation, the trip flatness and crown control model h...The strip flatness and crown control model is the foundation of automatic strip shape control. Considering the metal transverse flows and the inter stand second deformation, the trip flatness and crown control model has been developed, which can be applied to CVC mills and PC mills as well as normal four-high mills. The strip flatness and crown control model has high precision, and has been successfully applied to the automatic strip shape control system reconstruction of Tangshan Ganglu 1 250 mm hot strip plant.展开更多
The dynamic model of cold rolling mill based on strip flatness and thickness integrated control was proposed,containing the following sub-models:the rolling process model,the dynamic model of rolls along axial directi...The dynamic model of cold rolling mill based on strip flatness and thickness integrated control was proposed,containing the following sub-models:the rolling process model,the dynamic model of rolls along axial direction,and the compensation model.Based on the rule of volume flow rate,the dynamic rolling process model was built.The work roll and backup roll were taken as elastic continuous bodies,the effect of shear and moment of inertia were taken into consideration,and then the dynamic model of rolls was built.The two models were coupled together,and the dynamic model of rolling mill was built.In the dynamic model,the thermal expansion of the rolls,the wear of the rolls and other related parameters can not be considered.In order to compensate the dynamic model,the coupled static model of rolls and strip was applied.Then,according to the inner relationship of these models,the dynamic model and the compensation model were coupled,and the dynamic model of rolling mill based on the strip flatness and thickness integrated control was built.The dynamic simulation of the rolling process was made,and the dynamic thickness and the dynamic flatness information were obtained.This model not only provides a theory basis for the virtual rolling,but also provides a platform for the application of advanced control theory.展开更多
Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the im...Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.展开更多
To achieve stable rolling,the influence of a tension mechanism of a large diameter ratio roll system on the rolling process of a strip flatness electromagnetic control rolling mill is studied.Through the analysis of t...To achieve stable rolling,the influence of a tension mechanism of a large diameter ratio roll system on the rolling process of a strip flatness electromagnetic control rolling mill is studied.Through the analysis of the rolling deformation zone,the deformation zone composition form of a large diameter ratio roll system and a calculation formula of neutral angle under tension are proposed.To analyze the effect of front and post tensions on the rolling characteristic and the strip flatness control characteristic,a three-dimensional rolling finite element(FE)model of a large diameter ratio roll system with the function of roll profile electromagnetic control is established by FE software and verified by a strip flatness electromagnetic control rolling mill.Based on the model,the strip thickness characteristic,metal transverse flow,strip flatness state,and adjustment range of the loaded roll gap are analyzed for different front and post tensions setting values.The results show that changing the front or post tension setting values can improve the single-pass reduction rate of a large diameter ratio roll system and have little effect on the flatness control ability of the strip flatness electromagnetic control rolling mill.展开更多
Non-uniformity of temperature distribution across strip width direction is the ultimate reason why the flatness defect occurs on the strip after cooling process although the strip is flat at the exit of finishing mill...Non-uniformity of temperature distribution across strip width direction is the ultimate reason why the flatness defect occurs on the strip after cooling process although the strip is flat at the exit of finishing mill.One thermal , microstructural and mechanical coupling analysis model for predicting flatness change of steel strip during the run-out table cooling process was established using ABAQUS finite element software.K Esaka phase transformation kinetics model was employed to calculate the phase transformation , and coupled with temperature calculation using the user subroutine program HETVAL.Elasto-plasticity constitutive equations of steel material , in which conventional elastic and plastic strains , thermal strain , phase transformation strain and transformation induced plastic strain were considered , were derived and programmed in the user subroutine program UMAT.The conclusion that flatness of steel strip will develop to edge wave defect under the functions of the differential thermal and microstructural behaviors across strip width during the run-out table cooling procedure was acquired through the analysis results of this model.Calculation results of this analysis model agree well with the actual measurements and observation.展开更多
With the increasing demand for higher-quality flatness in downstream industries,the optimization of rolling processes and parameters has become a critical area of research.The effects of rolling force and front tensio...With the increasing demand for higher-quality flatness in downstream industries,the optimization of rolling processes and parameters has become a critical area of research.The effects of rolling force and front tension adjustments on flatness were examined systematically under various rolling process conditions.By embedding the Johnson-Cook constitutive model into the ABAQUS simulation platform through a user-defined subroutine,a series of three-dimensional finite element models for different rolling scenarios were developed.Simulation results indicate that,under all four rolling process conditions,edge strain consistently exceeds center strain,with forward-driven rolling exhibiting greater edge strain than reverse-driven rolling.Along the strip thickness direction,reverse-driven rolling results in higher strain compared to forward-driven rolling.Moreover,in single roll driven rolling,the upper surface of the strip experiences higher strain than the lower surface,while the reverse trend is observed in double roll driven rolling.As the rolling force increases from 1000 to 5000 kN,the strain difference in the width and thickness directions of the strip varies significantly under double roll driven rolling and double roll reverse-driven rolling,with change slopes of 5.74×10^(-6) and-2.85×10^(-6),respectively.Double roll driven rolling effectively prevents the deterioration of flatness along the rolling direction.Furthermore,as the front tension increases from 60 to 100 MPa,double roll reverse-driven rolling significantly suppresses strain differentials in the width,thickness,and rolling directions,with change slopes of-6.73×10^(-4),1.22×10^(-5),and-1.29×10^(-5),respectively.Eventually,a predictive model is established,integrating rolling process,rolling force,and front tension,thereby providing a theoretical framework for advancing the precision and efficiency of strip rolling processes.展开更多
The precision of strip flatness depends on several factors; wear of rolls is one of the main variables that have influence on the surface quality of the strip. The wear of the roils represents a complex friction condi...The precision of strip flatness depends on several factors; wear of rolls is one of the main variables that have influence on the surface quality of the strip. The wear of the roils represents a complex friction condition, sometimes the wear in the backup roll is not analyzed because the strip is not in contact with the backup roll; however, after several campaigns of rolling, the wear in the backup roll becomes dangerous because the pressure distribution is not uniform. Investigation of mechanism of the surface deterioration of the backup roll for the hot strip rolling is very important for the development of the automatic strip shape control system used in hot strip mills. A mathematical model is developed considering the Hertzian pressure distribution between two cylinders with parallel axes. It is used in real time for calculating the wear in the backup roll and in this manner take deci- sions for preventing finished product reworking or damage of equipments, which result in accidents caused by excessive wear in the backup rolls.展开更多
Cold-rolled thin strip steel of high flatness quality undergoes multistage deformation during tension leveling. Thus, the parameters of set-up and manipulating are more difficult. With the aid of FE code MSC. MARC, th...Cold-rolled thin strip steel of high flatness quality undergoes multistage deformation during tension leveling. Thus, the parameters of set-up and manipulating are more difficult. With the aid of FE code MSC. MARC, the tension leveling process of thin strip steel was numerically simulated. Concentrating on the influence of the roll intermeshes in 2# anti-cambering on the distribution and magnitude of residual stresses in leveled strip steel, several experiments were clone with the tension leveler based on the results from the simulation. It was found from the simulation that the magnitude of longitudinal residual stresses in the cross-section of the leveled strip steel regularly presents obvious interdependence with the roll intermeshes in 2# anti-cambering. In addition, there is a steady zone as the longitudinal residual stresses of the surface layers in leveled strip steel vary with the roll intermeshes of 2# anticambering, which is of importance in the manipulation of tension levelers. It was also found that the distribution of strains and stresses across the width of strip steel is uneven during leveling or after removing the tension loaded upon the strip, from which it was found that 3D simulation could not be replaced by 2D analysis because 2D analysis in this case cannot represent the physical behavior of strip steel deformation during tension leveling.展开更多
Shape setup （SSU） system is the core technology for hot strip mill （HSM）. A precise SSU system was used to improve the strip quality for HSM. The function of SSU, setup, and feedback was introduced. The main mathe...Shape setup （SSU） system is the core technology for hot strip mill （HSM）. A precise SSU system was used to improve the strip quality for HSM. The function of SSU, setup, and feedback was introduced. The main mathematical models of roll gap profile and longitudinal strain difference are set up. Strip profile allocation strategy was researched according to the SSU system of a domestic 1 700 mm HSM. The SSU system was put into practical use and the measurement results showed that strip flatness variation and strip profile variation could be controlled in target scope.展开更多
Baostrip has chosen a steel-grade weathering steel for industrial trial. By carefully designing the composition and manufacturing process,qualified weathering-steel products have been successfully produced on the Ning...Baostrip has chosen a steel-grade weathering steel for industrial trial. By carefully designing the composition and manufacturing process,qualified weathering-steel products have been successfully produced on the Ningbosteel-Baosteel strip casting industrialization demo project( NBS) production line. The industrialized practice of Baostrip shows the following: The surface microstructure of weathering-steel products is polygonal ferrite +pearlite,and that of the center is acicular ferrite. After single-stand on-line hot rolling at a 26% low pressure rate,the thickness tolerance ratio controlled within ± 25 μm reaches 99. 6%. The surface convexity and the wedge can be controlled to | C40 |< 50 μm and | W40 |< 30 μm,respectively. The mechanical properties of the strip are superior,exhibiting a yield strength range of( 430 ± 50) MPa,a tensile strength range of( 550 ± 50) MPa,and an elongation range of( 27 ± 5)%. The corrosion resistance is equivalent to that of current commercial atmospheric corrosion-resistant steels,with a relative corrosion rate of 43%. When used,the weathering steel produced by the strip-casting process meets the strict quality and usage requirements of container steel sheets.展开更多
基金Item Sponsored by National Natural Science Foundation of China (50534020)
文摘The strip flatness and crown control model is the foundation of automatic strip shape control. Considering the metal transverse flows and the inter stand second deformation, the trip flatness and crown control model has been developed, which can be applied to CVC mills and PC mills as well as normal four-high mills. The strip flatness and crown control model has high precision, and has been successfully applied to the automatic strip shape control system reconstruction of Tangshan Ganglu 1 250 mm hot strip plant.
基金Project(E2012203177)supported by the Natural Science Foundation of Hebei Province,ChinaProject(2011BAF15B01)supported by the National Science and Technology Support Plan of China+1 种基金Project(E2006001038)supported by Great Natural Science Foundation of Hebei Province,ChinaProject(NECSR-201202)supported by Open Project Program of National Engineering Research Center for Equipment and Technology of Cold Strip Rolling,China
文摘The dynamic model of cold rolling mill based on strip flatness and thickness integrated control was proposed,containing the following sub-models:the rolling process model,the dynamic model of rolls along axial direction,and the compensation model.Based on the rule of volume flow rate,the dynamic rolling process model was built.The work roll and backup roll were taken as elastic continuous bodies,the effect of shear and moment of inertia were taken into consideration,and then the dynamic model of rolls was built.The two models were coupled together,and the dynamic model of rolling mill was built.In the dynamic model,the thermal expansion of the rolls,the wear of the rolls and other related parameters can not be considered.In order to compensate the dynamic model,the coupled static model of rolls and strip was applied.Then,according to the inner relationship of these models,the dynamic model and the compensation model were coupled,and the dynamic model of rolling mill based on the strip flatness and thickness integrated control was built.The dynamic simulation of the rolling process was made,and the dynamic thickness and the dynamic flatness information were obtained.This model not only provides a theory basis for the virtual rolling,but also provides a platform for the application of advanced control theory.
基金supported by National Natural Science Foundation of China(Grant No. 50675186)Hebei Provincial Major Natural Science Foundation of China (Grant No. E2006001038)
文摘Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.
基金supported by the Natural Science Foundation of Hebei Province of China(Grant No.E2021203129).
文摘To achieve stable rolling,the influence of a tension mechanism of a large diameter ratio roll system on the rolling process of a strip flatness electromagnetic control rolling mill is studied.Through the analysis of the rolling deformation zone,the deformation zone composition form of a large diameter ratio roll system and a calculation formula of neutral angle under tension are proposed.To analyze the effect of front and post tensions on the rolling characteristic and the strip flatness control characteristic,a three-dimensional rolling finite element(FE)model of a large diameter ratio roll system with the function of roll profile electromagnetic control is established by FE software and verified by a strip flatness electromagnetic control rolling mill.Based on the model,the strip thickness characteristic,metal transverse flow,strip flatness state,and adjustment range of the loaded roll gap are analyzed for different front and post tensions setting values.The results show that changing the front or post tension setting values can improve the single-pass reduction rate of a large diameter ratio roll system and have little effect on the flatness control ability of the strip flatness electromagnetic control rolling mill.
文摘Non-uniformity of temperature distribution across strip width direction is the ultimate reason why the flatness defect occurs on the strip after cooling process although the strip is flat at the exit of finishing mill.One thermal , microstructural and mechanical coupling analysis model for predicting flatness change of steel strip during the run-out table cooling process was established using ABAQUS finite element software.K Esaka phase transformation kinetics model was employed to calculate the phase transformation , and coupled with temperature calculation using the user subroutine program HETVAL.Elasto-plasticity constitutive equations of steel material , in which conventional elastic and plastic strains , thermal strain , phase transformation strain and transformation induced plastic strain were considered , were derived and programmed in the user subroutine program UMAT.The conclusion that flatness of steel strip will develop to edge wave defect under the functions of the differential thermal and microstructural behaviors across strip width during the run-out table cooling procedure was acquired through the analysis results of this model.Calculation results of this analysis model agree well with the actual measurements and observation.
基金supported by National Key R&D Program of China(No.2024YFB4007100).
文摘With the increasing demand for higher-quality flatness in downstream industries,the optimization of rolling processes and parameters has become a critical area of research.The effects of rolling force and front tension adjustments on flatness were examined systematically under various rolling process conditions.By embedding the Johnson-Cook constitutive model into the ABAQUS simulation platform through a user-defined subroutine,a series of three-dimensional finite element models for different rolling scenarios were developed.Simulation results indicate that,under all four rolling process conditions,edge strain consistently exceeds center strain,with forward-driven rolling exhibiting greater edge strain than reverse-driven rolling.Along the strip thickness direction,reverse-driven rolling results in higher strain compared to forward-driven rolling.Moreover,in single roll driven rolling,the upper surface of the strip experiences higher strain than the lower surface,while the reverse trend is observed in double roll driven rolling.As the rolling force increases from 1000 to 5000 kN,the strain difference in the width and thickness directions of the strip varies significantly under double roll driven rolling and double roll reverse-driven rolling,with change slopes of 5.74×10^(-6) and-2.85×10^(-6),respectively.Double roll driven rolling effectively prevents the deterioration of flatness along the rolling direction.Furthermore,as the front tension increases from 60 to 100 MPa,double roll reverse-driven rolling significantly suppresses strain differentials in the width,thickness,and rolling directions,with change slopes of-6.73×10^(-4),1.22×10^(-5),and-1.29×10^(-5),respectively.Eventually,a predictive model is established,integrating rolling process,rolling force,and front tension,thereby providing a theoretical framework for advancing the precision and efficiency of strip rolling processes.
文摘The precision of strip flatness depends on several factors; wear of rolls is one of the main variables that have influence on the surface quality of the strip. The wear of the roils represents a complex friction condition, sometimes the wear in the backup roll is not analyzed because the strip is not in contact with the backup roll; however, after several campaigns of rolling, the wear in the backup roll becomes dangerous because the pressure distribution is not uniform. Investigation of mechanism of the surface deterioration of the backup roll for the hot strip rolling is very important for the development of the automatic strip shape control system used in hot strip mills. A mathematical model is developed considering the Hertzian pressure distribution between two cylinders with parallel axes. It is used in real time for calculating the wear in the backup roll and in this manner take deci- sions for preventing finished product reworking or damage of equipments, which result in accidents caused by excessive wear in the backup rolls.
基金Item Sponsored by Korea Research Foundation (KRF-2004-005-D00111)
文摘Cold-rolled thin strip steel of high flatness quality undergoes multistage deformation during tension leveling. Thus, the parameters of set-up and manipulating are more difficult. With the aid of FE code MSC. MARC, the tension leveling process of thin strip steel was numerically simulated. Concentrating on the influence of the roll intermeshes in 2# anti-cambering on the distribution and magnitude of residual stresses in leveled strip steel, several experiments were clone with the tension leveler based on the results from the simulation. It was found from the simulation that the magnitude of longitudinal residual stresses in the cross-section of the leveled strip steel regularly presents obvious interdependence with the roll intermeshes in 2# anti-cambering. In addition, there is a steady zone as the longitudinal residual stresses of the surface layers in leveled strip steel vary with the roll intermeshes of 2# anticambering, which is of importance in the manipulation of tension levelers. It was also found that the distribution of strains and stresses across the width of strip steel is uneven during leveling or after removing the tension loaded upon the strip, from which it was found that 3D simulation could not be replaced by 2D analysis because 2D analysis in this case cannot represent the physical behavior of strip steel deformation during tension leveling.
基金Item Sponsored by National Natural Science Foundation of China (50534020)
文摘Shape setup （SSU） system is the core technology for hot strip mill （HSM）. A precise SSU system was used to improve the strip quality for HSM. The function of SSU, setup, and feedback was introduced. The main mathematical models of roll gap profile and longitudinal strain difference are set up. Strip profile allocation strategy was researched according to the SSU system of a domestic 1 700 mm HSM. The SSU system was put into practical use and the measurement results showed that strip flatness variation and strip profile variation could be controlled in target scope.
基金funded by Shanghai Engineering Research Center of Strip Casting and Rolling(No.11DZ2282300)
文摘Baostrip has chosen a steel-grade weathering steel for industrial trial. By carefully designing the composition and manufacturing process,qualified weathering-steel products have been successfully produced on the Ningbosteel-Baosteel strip casting industrialization demo project( NBS) production line. The industrialized practice of Baostrip shows the following: The surface microstructure of weathering-steel products is polygonal ferrite +pearlite,and that of the center is acicular ferrite. After single-stand on-line hot rolling at a 26% low pressure rate,the thickness tolerance ratio controlled within ± 25 μm reaches 99. 6%. The surface convexity and the wedge can be controlled to | C40 |< 50 μm and | W40 |< 30 μm,respectively. The mechanical properties of the strip are superior,exhibiting a yield strength range of( 430 ± 50) MPa,a tensile strength range of( 550 ± 50) MPa,and an elongation range of( 27 ± 5)%. The corrosion resistance is equivalent to that of current commercial atmospheric corrosion-resistant steels,with a relative corrosion rate of 43%. When used,the weathering steel produced by the strip-casting process meets the strict quality and usage requirements of container steel sheets.
