Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromag...Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromagnetic parameters were obtained from the previous studies. Owing to the induction heating of a high frequency electromagnetic field (20 kHz), the thickness of initial solidification shell decreases, and the temperature of strand surface and slit copper mold increases when compared with the case without the electromagnetic filed. The viscosity of flux de- creases because of the induction heating of the high frequency electromagnetic field, and the dimension of the flux channel increases with electromagnetic pressure; thus, the deformation behavior of initial solidification shell was different before and after the action of high frequency electromagnetic field. Furthermore, the abatement mechanism of oscillation marks under high frequency electromagnetic field was explained.展开更多
Mold is the heart of the continuous casting machine. Heat transfer and solidification in a water- cooled mold are the most important factors during the continuous casting of steel. For studying the temperature distrib...Mold is the heart of the continuous casting machine. Heat transfer and solidification in a water- cooled mold are the most important factors during the continuous casting of steel. For studying the temperature distribution of a mold wall, a simulated apparatus of mold was designed and experiments were performed by it. The measured results indicated that the mold wall temperature approaches the temperature of cooling-water. An equivalent thermal-conductivity coefficient was proposed and deduced on the basis of the conclusion of the experiments. This coefficient was applied to solve the heat transfer between the melt and cooling water, and to characterize the heat transfer capacity of the mold. By this equivalent thermal-conductivity coefficient, it is very easy and convenient to numerically simulate the solidification process of continuous casting. And the calculation results are in agreement with the experiments. The effects of custing speed and water flow rate on the mold temperature field were also discussed.展开更多
The 3-dimensional fluid flow in a water model of the continuous casting tundish is simulated with the k-ε two-equation turbulence model. The methods to decide the size of wall-adjacent grids and the effects of resid...The 3-dimensional fluid flow in a water model of the continuous casting tundish is simulated with the k-ε two-equation turbulence model. The methods to decide the size of wall-adjacent grids and the effects of residuals and mesh size on the simulation accuracy are discussed. The current investigation concludes that the following condition should be satisfied to get accurate enough simulation results: (1) If the dimension of the domain is in the order of cubic meters, the average size of cells in the mesh system should be at least smaller than 30 mm; (2) The normalized non-scaled residual should be reached at least smaller than 10-4.展开更多
The effects of various factors, such as argon flow rate and slide gate opening ratio, on the alumina deposition rate were researched by the numerical simulation method. The pressure in the nozzle is significantly affe...The effects of various factors, such as argon flow rate and slide gate opening ratio, on the alumina deposition rate were researched by the numerical simulation method. The pressure in the nozzle is significantly affected by argon flow rate and slide gate opening ratio. To keep positive pressure in the nozzle, the argon flow rate should be increased with a decrease in slide gate opening ratio. The effect of argon flow rate on the alumina deposition rate depends on the condition of opening ratio or casting speed. The effect of increasing the argon flow rate on the deposition rate is not obvious when the opening ratio is small. The A1203 deposition rate decreases significantly with an increase in argon flow rate when the argon flow rate is low, but it decreases slowly when the argon flow rate reaches a certain value. The alumina deposition rate is linear with alumina content at different slide gate opening ratios and argon flow rates. The observed thickness of the deposition layer at the bottom and outlet of a real clogged nozzle is almost equal to the result of the numerical simulation.展开更多
A general mathematical model and boundary condition applicable to momentum and heat transfer in the semisolid continuous casting(SCC) process was established. Using the model, the numerical simulation of the momentum ...A general mathematical model and boundary condition applicable to momentum and heat transfer in the semisolid continuous casting(SCC) process was established. Using the model, the numerical simulation of the momentum and heat transfer of molten metal was carried out in the SCC system. The obtained results fit well with the measured ones. Moreover, using the numerical simulating software, the effect of various factors on breakout and breakage was explored. The obtained results show that heat flow density of copper mold and the withdrawal beginning time are two major influencing factors. The larger the heat flow density of copper mold, or the shorter the withdrawal beginning time, the more stable the semisolid continuous casting process. [展开更多
In this study, the temperature field model of twin-roll thin strip continuous casting was developed, and the interface heat transfer coefficient between the air and the strip surface was computed by using the inverse ...In this study, the temperature field model of twin-roll thin strip continuous casting was developed, and the interface heat transfer coefficient between the air and the strip surface was computed by using the inverse method. The effects of the process parameters including the casting speed, liquid level height, pouring temperature and thickness of the thin strip on the outlet temperature of the rotating rolls and the surface temperature of the thin strip were analyzed.展开更多
In order to improve the strip quality of continuous roll-casting process (CRP) of aluminum alloy, the investigations of the flow behavior within the metal pool, the heat transfer condition between roll and strip, the ...In order to improve the strip quality of continuous roll-casting process (CRP) of aluminum alloy, the investigations of the flow behavior within the metal pool, the heat transfer condition between roll and strip, the pouring temperature of molten alloy, the roll-casting speed and the control of the position of solidification final point are important. The finite volume method was applied to the analysis of the continuous roll-casting process. A two-dimensional incompressible non-Newtonian fluid flow with heat transfer was considered, which was described by the continuity equation, the Navier-Stokes equation and the energy equation. With this mathematical model, the flow patterns, temperature fields and solid fraction distributions in the metal pool between two rolls were simulated. From the calculated results, the effects of technical parameters to the position of solidification final point are obtained. The simulated results show that the roll-casting speed and pouring temperature have an enormous effect on the temperature distribution and the position of solidification final point.展开更多
This work is focused on the development of computational algorithms to create a simulator for solving the heat transfer during the continuous casting process of steel. The temperatures and the solid shell thickness pr...This work is focused on the development of computational algorithms to create a simulator for solving the heat transfer during the continuous casting process of steel. The temperatures and the solid shell thickness profiles were calculated and displayed on the screen for a billet through a defined continuous casting plant (CCP). The algorithms developed to calculate billet temperatures, involve the solutions of the corresponding equations for the heat removal conditions such as radiation, forced convection, and conduction according to the billet posi- tion through the CCP. This is done by a simultaneous comparison with the kinematics model previously developed. A finite difference method known as Cmnk-Nicholson is applied to solve the two-dimensional computational array (2D model). Enthalpy (HIJ) and temperature (TIL) in every node are updated at each step time. The routines to display the results have been developed using a graphical user interface (GUI) in the programming language C++. Finally, the results obtained are compared with those of industrial trials for the surface temperature of three steel casters with different plant configurations in different casting conditions.展开更多
Thin slab casting is used widely in the world. The control of molten steel flow and solidification in the mold is difficult due to the high casting speed and complicated configuration of the mold. Numerical simulation...Thin slab casting is used widely in the world. The control of molten steel flow and solidification in the mold is difficult due to the high casting speed and complicated configuration of the mold. Numerical simulation was carried out to study the fluid flow and heat transfer in the funnel shaped mold. The influence of nozzle design, casting speed and nozzle submersion depth on the flow and temperature fields in the mold was investigated, and guidance for selecting configurations of submerged nozzle was obtained.展开更多
The factors involved in simulating the continuous casting process of steel and the effects of the factors on the thermal behavior were investigated. The numerical methods and the influence of some assumptions were als...The factors involved in simulating the continuous casting process of steel and the effects of the factors on the thermal behavior were investigated. The numerical methods and the influence of some assumptions were also analyzed, such as nodes used to discretize the steel in array size and computing time to obtain good approaches. The results show that some of these factors are related with the design of the continuous casting plant (CCP), such as geometrical configuration, and the operating conditions, such as water flow rate, heat removal coefficient in the mold, casting times, and casting speed in the strand, which affect the heat removal conditions over the temperature and solidification profiles.展开更多
Electromagnetic casting technology became maturity and gained wide applications in steel-making and aluminum casting, which is still immature in copper casting. Electromagnetic continuous casting with soft-contact mol...Electromagnetic casting technology became maturity and gained wide applications in steel-making and aluminum casting, which is still immature in copper casting. Electromagnetic continuous casting with soft-contact mold was employed to produce copper round billet with high density. At the same time, in this paper, a mathematical model of the electromagnetic field in the soft-contact mold was built on the base of the vector potential method, then it was solved by the ANSYS commercial FEM software. Current and frequency was altered in the course of operation so as to find out how they effect the magnetic field distributing. Its accuracy was verified by the measurement result of the electromagnetic field in the mold without billet. By this model, the effect of excitation current on field was gained, which set up a certainty foundation for more research.展开更多
The solidification process of a horizontally continuously cast gray iron bar of 4.6cm in diame- ter was modelled.The function describing the distribution of heat flux at the internal surface of graphite sleeve,which w...The solidification process of a horizontally continuously cast gray iron bar of 4.6cm in diame- ter was modelled.The function describing the distribution of heat flux at the internal surface of graphite sleeve,which was equal to that on the surface of the iron bar,was inversely derived using numerical calculation from the temperature distribution in the sleeve measured in real production.By using the distribution of heat flux as a boundary condition on the surface of the iron bar,the numerical simulation on solidification of the iron bar taking longitudinal heat conduction into account was made.The profile of solidification front obtained from the numer- ical simulation was approximately coincident with that in real production.In addition,the quantitative relationships of the thickness of solidified shell at the exit of the mold to the main technological parameters,including the temperature of liquid iron at the entrance of the mold, the moving speed of the bar and the intensity of water cooling,were obtained from the numeri- cal simulation.展开更多
To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models have been developed to describe the thermal process. Then Fini...To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models have been developed to describe the thermal process. Then Finite Element Method (FEM) has been applied to simulate the solidification process. Parameters including casting speed, casting temperature and cooling conditions have been analyzed. It is shown that different parameters have different influence on the thermal process and must be carefully controlled in continuous casting process. Finally, the simulated results are compared with the experimental ones.展开更多
Computational simulations and high-temperature measurements of velocities near the surface of a mold were carried out by using the rod deflection method to study the effects of various operating parameters on the flow...Computational simulations and high-temperature measurements of velocities near the surface of a mold were carried out by using the rod deflection method to study the effects of various operating parameters on the flow field in slab continuous casting(CC)molds with narrow widths for the production of automobile exposed panels.Reasonable agreement between the calculated results and measured subsurface velocities of liquid steel was obtained under different operating parameters of the CC process.The simulation results reveal that the flow field in the horizontal plane located 50 mm from the meniscus can be used as the characteristic flow field to optimize the flow field of molten steel in the mold.Increases in casting speed can increase the subsurface velocity of molten steel and shift the position of the vortex core downward in the downward circulation zone.The flow field of liquid steel in a 1040 mm-wide slab CC mold can be improved by an Ar gas flow rate of 7 L·min^−1 and casting speed of 1.7 m·min^−1.Under the present experimental conditions,the double-roll flow pattern is generally stable at a submerged entry nozzle immersion depth of 170 mm.展开更多
Coupling the quasi 3D numerical simulation of electromagnetic field and the experiments with some metals such as tin, aluminum, copper and steel, the electromagnetic characteristics of continuous casting with soft con...Coupling the quasi 3D numerical simulation of electromagnetic field and the experiments with some metals such as tin, aluminum, copper and steel, the electromagnetic characteristics of continuous casting with soft contacted mould, especially the influences of power frequency, the mould structure, and the inductor position, size and current on the electromagnetic force and pressure on the billet, were analyzed. The result shows that, in continuous casting with soft contacted mould, the electromagnetic pressure on the surface of billet increases with the rising of the power frequency as a logarithmically parabolic function and, with that of inductor current as a parabolic function. The design principle of the soft contacted mould is that 1) the mould structure should be ‘more segments and thin slits’; 2) the topside of inductor should be at the same location with the meniscus of molten metal; 3) the inductor should cover the initial solidifying shell of billet.展开更多
Computational simulation is a very powerful tool to analyze industrial processes to reduce operating risks and improve profits from equipment. The present work describes the development of some computational algorithm...Computational simulation is a very powerful tool to analyze industrial processes to reduce operating risks and improve profits from equipment. The present work describes the development of some computational algorithms based on the numerical method to create a simulator for the continuous casting process, which is the most popular method to produce steel products for metallurgical industries. The kinematics of industrial processing was computationally reproduced using subroutines logically programmed. The cast steel by each strand was calculated using an iterative method nested in the main loop. The process was repeated at each time step (?t) to calculate the casting time, simultaneously, the steel billets produced were counted and stored. The subroutines were used for creating a computational representation of a continuous casting plant (CCP) and displaying the simulation of the steel displacement through the CCP. These algorithms have been developed to create a simulator using the programming language C++. Algorithms for computer animation of the continuous casting process were created using a graphical user interface (GUI). Finally, the simulator functionality was shown and validated by comparing with the industrial information of the steel production of three casters.展开更多
A coupled model including electromagnetic field, fluid dynamic, heat transfer and solidification, is developed and applied to the numerical simulation of steel flow and solidification in a 100mm × 100mm soft-cont...A coupled model including electromagnetic field, fluid dynamic, heat transfer and solidification, is developed and applied to the numerical simulation of steel flow and solidification in a 100mm × 100mm soft-contact mold. In this study, the 3D finite difference method and non-staggered grid system for fluid flow with body fitted coordinate were employed. Numerical results show that the electromagnetic force mainly affects the steel flow at upper part of mold, especially in the vicinity of meniscus. There exist upward flows covering the surfaces of the billet due to the concentration of electromagnetic force on the upper part of the billet. This flows join together and form a downward flow near the SEN, so a distinct circulating flow zone is formed at upper part of mold. After applying electromagnetic force, the steel velocity is improved and the temperature is raised. The strong stirring of electromagnetic force on liquid steel makes the kinetic energy on free surface increase. It is clearly seen that the solidification start point shifts downward in soft contact mold. As a result, the initial shell thickness gets thin and the initial solidification shell length is shortened.展开更多
In this paper, coupling the quasi-3D numerical simulation of electromagnetic field and the experiments of continuous casting with soft-contacted mould with some metals such as tin, aluminum, copper and steel, the elec...In this paper, coupling the quasi-3D numerical simulation of electromagnetic field and the experiments of continuous casting with soft-contacted mould with some metals such as tin, aluminum, copper and steel, the electromagnetic characteristics of continuous casting with soft-contacted mould is analyzed. It is shown that the electromagnetic pressure on the surface of billet is increasing with the rising of power frequency as a logarithmically parabolic function, with that of electric conductivity of billet as a power junction, and with that of the current in inductor as a parabolic junction.展开更多
Based on the solidification heat transfer model and CAFÉmodel,the solidification structure of GCr15 bloom alloy was studied.Using nail shooting and acid etching experiments,the solidification models were verified...Based on the solidification heat transfer model and CAFÉmodel,the solidification structure of GCr15 bloom alloy was studied.Using nail shooting and acid etching experiments,the solidification models were verified.The secondary dendrite arm spacing(SDAS)model of GCr15 was obtained by simulation calculation and metallographic observation.With the increase of casting speed,the SDAS,equiaxed crystal ratio(ECR)and average grain size increase.With the rise of superheat,the SDAS increases in the 20-70 mm of thickness and decreases in the 80-160 mm of thickness.The ECR decreases and the average grain size increases with the increase of superheat.With the increase of specific water flow,both the SDAS and ECR decrease.The minimum average grain size is obtained when the specific water flow is 0.20 L·kg^(-1).The central carbon segregation index is reduced from 1.11 to 1.075.展开更多
基金Item Sponsored by National Natural Science Foundation of China (59734080)
文摘Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromagnetic parameters were obtained from the previous studies. Owing to the induction heating of a high frequency electromagnetic field (20 kHz), the thickness of initial solidification shell decreases, and the temperature of strand surface and slit copper mold increases when compared with the case without the electromagnetic filed. The viscosity of flux de- creases because of the induction heating of the high frequency electromagnetic field, and the dimension of the flux channel increases with electromagnetic pressure; thus, the deformation behavior of initial solidification shell was different before and after the action of high frequency electromagnetic field. Furthermore, the abatement mechanism of oscillation marks under high frequency electromagnetic field was explained.
基金the National Natural Science Foundation of China (No. 599995442).
文摘Mold is the heart of the continuous casting machine. Heat transfer and solidification in a water- cooled mold are the most important factors during the continuous casting of steel. For studying the temperature distribution of a mold wall, a simulated apparatus of mold was designed and experiments were performed by it. The measured results indicated that the mold wall temperature approaches the temperature of cooling-water. An equivalent thermal-conductivity coefficient was proposed and deduced on the basis of the conclusion of the experiments. This coefficient was applied to solve the heat transfer between the melt and cooling water, and to characterize the heat transfer capacity of the mold. By this equivalent thermal-conductivity coefficient, it is very easy and convenient to numerically simulate the solidification process of continuous casting. And the calculation results are in agreement with the experiments. The effects of custing speed and water flow rate on the mold temperature field were also discussed.
文摘The 3-dimensional fluid flow in a water model of the continuous casting tundish is simulated with the k-ε two-equation turbulence model. The methods to decide the size of wall-adjacent grids and the effects of residuals and mesh size on the simulation accuracy are discussed. The current investigation concludes that the following condition should be satisfied to get accurate enough simulation results: (1) If the dimension of the domain is in the order of cubic meters, the average size of cells in the mesh system should be at least smaller than 30 mm; (2) The normalized non-scaled residual should be reached at least smaller than 10-4.
基金the State Economic and Trade Commission of China(No.01BK-098-02-07)
文摘The effects of various factors, such as argon flow rate and slide gate opening ratio, on the alumina deposition rate were researched by the numerical simulation method. The pressure in the nozzle is significantly affected by argon flow rate and slide gate opening ratio. To keep positive pressure in the nozzle, the argon flow rate should be increased with a decrease in slide gate opening ratio. The effect of argon flow rate on the alumina deposition rate depends on the condition of opening ratio or casting speed. The effect of increasing the argon flow rate on the deposition rate is not obvious when the opening ratio is small. The A1203 deposition rate decreases significantly with an increase in argon flow rate when the argon flow rate is low, but it decreases slowly when the argon flow rate reaches a certain value. The alumina deposition rate is linear with alumina content at different slide gate opening ratios and argon flow rates. The observed thickness of the deposition layer at the bottom and outlet of a real clogged nozzle is almost equal to the result of the numerical simulation.
文摘A general mathematical model and boundary condition applicable to momentum and heat transfer in the semisolid continuous casting(SCC) process was established. Using the model, the numerical simulation of the momentum and heat transfer of molten metal was carried out in the SCC system. The obtained results fit well with the measured ones. Moreover, using the numerical simulating software, the effect of various factors on breakout and breakage was explored. The obtained results show that heat flow density of copper mold and the withdrawal beginning time are two major influencing factors. The larger the heat flow density of copper mold, or the shorter the withdrawal beginning time, the more stable the semisolid continuous casting process. [
文摘In this study, the temperature field model of twin-roll thin strip continuous casting was developed, and the interface heat transfer coefficient between the air and the strip surface was computed by using the inverse method. The effects of the process parameters including the casting speed, liquid level height, pouring temperature and thickness of the thin strip on the outlet temperature of the rotating rolls and the surface temperature of the thin strip were analyzed.
基金Projects(50374014 50674017) supported by the National Natural Science Foundation of China
文摘In order to improve the strip quality of continuous roll-casting process (CRP) of aluminum alloy, the investigations of the flow behavior within the metal pool, the heat transfer condition between roll and strip, the pouring temperature of molten alloy, the roll-casting speed and the control of the position of solidification final point are important. The finite volume method was applied to the analysis of the continuous roll-casting process. A two-dimensional incompressible non-Newtonian fluid flow with heat transfer was considered, which was described by the continuity equation, the Navier-Stokes equation and the energy equation. With this mathematical model, the flow patterns, temperature fields and solid fraction distributions in the metal pool between two rolls were simulated. From the calculated results, the effects of technical parameters to the position of solidification final point are obtained. The simulated results show that the roll-casting speed and pouring temperature have an enormous effect on the temperature distribution and the position of solidification final point.
文摘This work is focused on the development of computational algorithms to create a simulator for solving the heat transfer during the continuous casting process of steel. The temperatures and the solid shell thickness profiles were calculated and displayed on the screen for a billet through a defined continuous casting plant (CCP). The algorithms developed to calculate billet temperatures, involve the solutions of the corresponding equations for the heat removal conditions such as radiation, forced convection, and conduction according to the billet posi- tion through the CCP. This is done by a simultaneous comparison with the kinematics model previously developed. A finite difference method known as Cmnk-Nicholson is applied to solve the two-dimensional computational array (2D model). Enthalpy (HIJ) and temperature (TIL) in every node are updated at each step time. The routines to display the results have been developed using a graphical user interface (GUI) in the programming language C++. Finally, the results obtained are compared with those of industrial trials for the surface temperature of three steel casters with different plant configurations in different casting conditions.
文摘Thin slab casting is used widely in the world. The control of molten steel flow and solidification in the mold is difficult due to the high casting speed and complicated configuration of the mold. Numerical simulation was carried out to study the fluid flow and heat transfer in the funnel shaped mold. The influence of nozzle design, casting speed and nozzle submersion depth on the flow and temperature fields in the mold was investigated, and guidance for selecting configurations of submerged nozzle was obtained.
文摘The factors involved in simulating the continuous casting process of steel and the effects of the factors on the thermal behavior were investigated. The numerical methods and the influence of some assumptions were also analyzed, such as nodes used to discretize the steel in array size and computing time to obtain good approaches. The results show that some of these factors are related with the design of the continuous casting plant (CCP), such as geometrical configuration, and the operating conditions, such as water flow rate, heat removal coefficient in the mold, casting times, and casting speed in the strand, which affect the heat removal conditions over the temperature and solidification profiles.
文摘Electromagnetic casting technology became maturity and gained wide applications in steel-making and aluminum casting, which is still immature in copper casting. Electromagnetic continuous casting with soft-contact mold was employed to produce copper round billet with high density. At the same time, in this paper, a mathematical model of the electromagnetic field in the soft-contact mold was built on the base of the vector potential method, then it was solved by the ANSYS commercial FEM software. Current and frequency was altered in the course of operation so as to find out how they effect the magnetic field distributing. Its accuracy was verified by the measurement result of the electromagnetic field in the mold without billet. By this model, the effect of excitation current on field was gained, which set up a certainty foundation for more research.
文摘The solidification process of a horizontally continuously cast gray iron bar of 4.6cm in diame- ter was modelled.The function describing the distribution of heat flux at the internal surface of graphite sleeve,which was equal to that on the surface of the iron bar,was inversely derived using numerical calculation from the temperature distribution in the sleeve measured in real production.By using the distribution of heat flux as a boundary condition on the surface of the iron bar,the numerical simulation on solidification of the iron bar taking longitudinal heat conduction into account was made.The profile of solidification front obtained from the numer- ical simulation was approximately coincident with that in real production.In addition,the quantitative relationships of the thickness of solidified shell at the exit of the mold to the main technological parameters,including the temperature of liquid iron at the entrance of the mold, the moving speed of the bar and the intensity of water cooling,were obtained from the numeri- cal simulation.
文摘To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models have been developed to describe the thermal process. Then Finite Element Method (FEM) has been applied to simulate the solidification process. Parameters including casting speed, casting temperature and cooling conditions have been analyzed. It is shown that different parameters have different influence on the thermal process and must be carefully controlled in continuous casting process. Finally, the simulated results are compared with the experimental ones.
基金This work was financially supported by the Hunan Valin Lianyuan Iron&Steel Co.,Ltd.,China(No.18H00582).The authors are grateful to Hunan Valin Lianyuan Iron&Steel Co.,Ltd.,China for their assistance with the industrial measurement of velocities near the mold surface.
文摘Computational simulations and high-temperature measurements of velocities near the surface of a mold were carried out by using the rod deflection method to study the effects of various operating parameters on the flow field in slab continuous casting(CC)molds with narrow widths for the production of automobile exposed panels.Reasonable agreement between the calculated results and measured subsurface velocities of liquid steel was obtained under different operating parameters of the CC process.The simulation results reveal that the flow field in the horizontal plane located 50 mm from the meniscus can be used as the characteristic flow field to optimize the flow field of molten steel in the mold.Increases in casting speed can increase the subsurface velocity of molten steel and shift the position of the vortex core downward in the downward circulation zone.The flow field of liquid steel in a 1040 mm-wide slab CC mold can be improved by an Ar gas flow rate of 7 L·min^−1 and casting speed of 1.7 m·min^−1.Under the present experimental conditions,the double-roll flow pattern is generally stable at a submerged entry nozzle immersion depth of 170 mm.
文摘Coupling the quasi 3D numerical simulation of electromagnetic field and the experiments with some metals such as tin, aluminum, copper and steel, the electromagnetic characteristics of continuous casting with soft contacted mould, especially the influences of power frequency, the mould structure, and the inductor position, size and current on the electromagnetic force and pressure on the billet, were analyzed. The result shows that, in continuous casting with soft contacted mould, the electromagnetic pressure on the surface of billet increases with the rising of the power frequency as a logarithmically parabolic function and, with that of inductor current as a parabolic function. The design principle of the soft contacted mould is that 1) the mould structure should be ‘more segments and thin slits’; 2) the topside of inductor should be at the same location with the meniscus of molten metal; 3) the inductor should cover the initial solidifying shell of billet.
文摘Computational simulation is a very powerful tool to analyze industrial processes to reduce operating risks and improve profits from equipment. The present work describes the development of some computational algorithms based on the numerical method to create a simulator for the continuous casting process, which is the most popular method to produce steel products for metallurgical industries. The kinematics of industrial processing was computationally reproduced using subroutines logically programmed. The cast steel by each strand was calculated using an iterative method nested in the main loop. The process was repeated at each time step (?t) to calculate the casting time, simultaneously, the steel billets produced were counted and stored. The subroutines were used for creating a computational representation of a continuous casting plant (CCP) and displaying the simulation of the steel displacement through the CCP. These algorithms have been developed to create a simulator using the programming language C++. Algorithms for computer animation of the continuous casting process were created using a graphical user interface (GUI). Finally, the simulator functionality was shown and validated by comparing with the industrial information of the steel production of three casters.
基金This project is supported by the National Natural Science Foundation of China (Grant No. 59734080) the Plan of National Fundamental Research Development of China (Grant No. G1998061510).
文摘A coupled model including electromagnetic field, fluid dynamic, heat transfer and solidification, is developed and applied to the numerical simulation of steel flow and solidification in a 100mm × 100mm soft-contact mold. In this study, the 3D finite difference method and non-staggered grid system for fluid flow with body fitted coordinate were employed. Numerical results show that the electromagnetic force mainly affects the steel flow at upper part of mold, especially in the vicinity of meniscus. There exist upward flows covering the surfaces of the billet due to the concentration of electromagnetic force on the upper part of the billet. This flows join together and form a downward flow near the SEN, so a distinct circulating flow zone is formed at upper part of mold. After applying electromagnetic force, the steel velocity is improved and the temperature is raised. The strong stirring of electromagnetic force on liquid steel makes the kinetic energy on free surface increase. It is clearly seen that the solidification start point shifts downward in soft contact mold. As a result, the initial shell thickness gets thin and the initial solidification shell length is shortened.
文摘In this paper, coupling the quasi-3D numerical simulation of electromagnetic field and the experiments of continuous casting with soft-contacted mould with some metals such as tin, aluminum, copper and steel, the electromagnetic characteristics of continuous casting with soft-contacted mould is analyzed. It is shown that the electromagnetic pressure on the surface of billet is increasing with the rising of power frequency as a logarithmically parabolic function, with that of electric conductivity of billet as a power junction, and with that of the current in inductor as a parabolic junction.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51774030 and U1860104)the Fundamental Research Funds for the Central Universities(FRF-TP-20-029A1)。
文摘Based on the solidification heat transfer model and CAFÉmodel,the solidification structure of GCr15 bloom alloy was studied.Using nail shooting and acid etching experiments,the solidification models were verified.The secondary dendrite arm spacing(SDAS)model of GCr15 was obtained by simulation calculation and metallographic observation.With the increase of casting speed,the SDAS,equiaxed crystal ratio(ECR)and average grain size increase.With the rise of superheat,the SDAS increases in the 20-70 mm of thickness and decreases in the 80-160 mm of thickness.The ECR decreases and the average grain size increases with the increase of superheat.With the increase of specific water flow,both the SDAS and ECR decrease.The minimum average grain size is obtained when the specific water flow is 0.20 L·kg^(-1).The central carbon segregation index is reduced from 1.11 to 1.075.