Combining with the physical model of level fluctuation in a thick slab continuous casting mold with the cross-section of 1500 mm×280 mm and argon blowing, the rationalities of estimating the level fluctuation by ...Combining with the physical model of level fluctuation in a thick slab continuous casting mold with the cross-section of 1500 mm×280 mm and argon blowing, the rationalities of estimating the level fluctuation by three traditional quantitative approaches were discussed, and the effects of gas flowrate, casting speed, and the immersion depth of submerged entry nozzle （SEN） on the level fluctuation were also investigated. As a result, it seems that three traditional quantitative approaches are not very suitable for estimating the level fluctuation in a mold with argon blowing, so a new approach for estimating level fluctuation in the mold with argon blowing was presented. The experimental results show that the level fluctuation is mainly in the region around the nozzle wall. When the casting speeds are larger than a certain value, there is the escape of large bubbles near the nozzle wall, which causes an obvious increase of level fluctuation. Furthermore, optimal process parameters, viz., the gas flowrate of 6 NL/min, the casting speed of 1.1 m/min, and the immersion depth of 170 mm, are presented to restrain the level fluctuation by a physical model.展开更多
Unsteady fluid flows and level fluctuations in a thin slab continuous casting mould have significant influence on product quality. In this study, the phenomena concerning transient flow features and free surface motio...Unsteady fluid flows and level fluctuations in a thin slab continuous casting mould have significant influence on product quality. In this study, the phenomena concerning transient flow features and free surface motions were analyzed by means of the large eddy simulation （LES） software with the smagorinsky SGS model--VisualCast （VCast） II, where the Simpler algorithm on a body-fitted mesh was used to resolve governing equations. A series of water analog experiments on the fluid flow and the surface wave in the moulds of thin slab continuous casting were also performed. The results of fluid regions, middle of vortex and level fluctuation from digital simulations were identical with the results of the water analog experiments.展开更多
The temperature of the meniscus in continuous casting was measured during mold oscillation by modeling experiments. It is found that the temperature of meniscus varied periodically along with mold oscillation. Based o...The temperature of the meniscus in continuous casting was measured during mold oscillation by modeling experiments. It is found that the temperature of meniscus varied periodically along with mold oscillation. Based on the above phenomenon, the mechanism of some techniques, such as, hot top mold, high frequency and low amplitude mold oscillation, soft contact mold electromagnetic continuous casting and so on, which can improve the quality of continuous casting billets, was analyzed. The results show that the decrease of the temperature fluctuation of early solidification shell is their common mechanism.展开更多
The free surface profile and fluid flow in the mold of continuous casting have been calculated by the VOF method couplingthe SIMPLER algorithm. The SIMPLER-VOF model developed is validated by solving a classical exper...The free surface profile and fluid flow in the mold of continuous casting have been calculated by the VOF method couplingthe SIMPLER algorithm. The SIMPLER-VOF model developed is validated by solving a classical experiment, broken damproblem. The calculated surface profile is consistent with water modelling. It is found that the free surface profile is coherentlyrelated to the position of circumfluence in the mold of continuous casting. With the increase of nozzle port inclination, thepositive vortex above the jet is near to the meniscus and the level fluctuation becomes prominent.展开更多
Hypo-peritectic steels are widely used in various industrial fields because of their high strength,high toughness,high processability,high weldability,and low material cost.However,surface defects are liable to occur ...Hypo-peritectic steels are widely used in various industrial fields because of their high strength,high toughness,high processability,high weldability,and low material cost.However,surface defects are liable to occur during continuous casting,which includes depression,longitudinal cracks,deep oscillation marks,and severe level fluctuation with slag entrapment.The high-efficiency production of hypo-peritectic steels by continuous casting is still a great challenge due to the limited understanding of the mechanism of peritectic solidification.This work reviews the definition and classification of hypo-peritectic steels and introduces the formation tendency of common surface defects related to peritectic solidification.New achievements in the mechanism of peritectic reaction and transformation have been listed.Finally,countermeasures to avoiding surface defects of hypo-peritectic steels duiring continuous casting are summarized.Enlightening certain points in the continuous casting of hypo-peritectic steels and the development of new techniques to overcome the present problems will be a great aid to researchers.展开更多
Using 0.6-scale warer modelling based on Fr-We number similitude criteria, the influences of the submerged entry nozzle configuration and operating practices on the level fluctuation in the mold which caused surface d...Using 0.6-scale warer modelling based on Fr-We number similitude criteria, the influences of the submerged entry nozzle configuration and operating practices on the level fluctuation in the mold which caused surface defects and mold power catching, were studied. It was found that the level flunction was resulted from gas injection, impacting of the stream and standing wave. The level turblence raises with the incresing of the gas injection, however the casting rate, immersion depth and jet angel of SEN have a dual influenc on the level fluctuation.展开更多
基金supported by the Fundamental Research Funds for the Central Universities (No.100402017)China Postdoctoral Science Foundation (No.20080431153)Scientific Research Foundation for Doctor of Liaoning Province, China (No.20071020)
文摘Combining with the physical model of level fluctuation in a thick slab continuous casting mold with the cross-section of 1500 mm×280 mm and argon blowing, the rationalities of estimating the level fluctuation by three traditional quantitative approaches were discussed, and the effects of gas flowrate, casting speed, and the immersion depth of submerged entry nozzle （SEN） on the level fluctuation were also investigated. As a result, it seems that three traditional quantitative approaches are not very suitable for estimating the level fluctuation in a mold with argon blowing, so a new approach for estimating level fluctuation in the mold with argon blowing was presented. The experimental results show that the level fluctuation is mainly in the region around the nozzle wall. When the casting speeds are larger than a certain value, there is the escape of large bubbles near the nozzle wall, which causes an obvious increase of level fluctuation. Furthermore, optimal process parameters, viz., the gas flowrate of 6 NL/min, the casting speed of 1.1 m/min, and the immersion depth of 170 mm, are presented to restrain the level fluctuation by a physical model.
文摘Unsteady fluid flows and level fluctuations in a thin slab continuous casting mould have significant influence on product quality. In this study, the phenomena concerning transient flow features and free surface motions were analyzed by means of the large eddy simulation （LES） software with the smagorinsky SGS model--VisualCast （VCast） II, where the Simpler algorithm on a body-fitted mesh was used to resolve governing equations. A series of water analog experiments on the fluid flow and the surface wave in the moulds of thin slab continuous casting were also performed. The results of fluid regions, middle of vortex and level fluctuation from digital simulations were identical with the results of the water analog experiments.
基金ProjectsupportedbytheNationalNaturalScienceFoundationof China (5 973 40 80 5 99740 17)
文摘The temperature of the meniscus in continuous casting was measured during mold oscillation by modeling experiments. It is found that the temperature of meniscus varied periodically along with mold oscillation. Based on the above phenomenon, the mechanism of some techniques, such as, hot top mold, high frequency and low amplitude mold oscillation, soft contact mold electromagnetic continuous casting and so on, which can improve the quality of continuous casting billets, was analyzed. The results show that the decrease of the temperature fluctuation of early solidification shell is their common mechanism.
文摘The free surface profile and fluid flow in the mold of continuous casting have been calculated by the VOF method couplingthe SIMPLER algorithm. The SIMPLER-VOF model developed is validated by solving a classical experiment, broken damproblem. The calculated surface profile is consistent with water modelling. It is found that the free surface profile is coherentlyrelated to the position of circumfluence in the mold of continuous casting. With the increase of nozzle port inclination, thepositive vortex above the jet is near to the meniscus and the level fluctuation becomes prominent.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.FRF-TP-19-017A3)the National Natural Science Foundation of China(No.51874026)。
文摘Hypo-peritectic steels are widely used in various industrial fields because of their high strength,high toughness,high processability,high weldability,and low material cost.However,surface defects are liable to occur during continuous casting,which includes depression,longitudinal cracks,deep oscillation marks,and severe level fluctuation with slag entrapment.The high-efficiency production of hypo-peritectic steels by continuous casting is still a great challenge due to the limited understanding of the mechanism of peritectic solidification.This work reviews the definition and classification of hypo-peritectic steels and introduces the formation tendency of common surface defects related to peritectic solidification.New achievements in the mechanism of peritectic reaction and transformation have been listed.Finally,countermeasures to avoiding surface defects of hypo-peritectic steels duiring continuous casting are summarized.Enlightening certain points in the continuous casting of hypo-peritectic steels and the development of new techniques to overcome the present problems will be a great aid to researchers.
文摘Using 0.6-scale warer modelling based on Fr-We number similitude criteria, the influences of the submerged entry nozzle configuration and operating practices on the level fluctuation in the mold which caused surface defects and mold power catching, were studied. It was found that the level flunction was resulted from gas injection, impacting of the stream and standing wave. The level turblence raises with the incresing of the gas injection, however the casting rate, immersion depth and jet angel of SEN have a dual influenc on the level fluctuation.
