A 3D/2D hybrid multi-physical-field mathematical model,which takes into consideration the thermosolutal buoyance,was developed to predict the macrosegregation of gear steel 20CrMnTi continuously cast by a curved bille...A 3D/2D hybrid multi-physical-field mathematical model,which takes into consideration the thermosolutal buoyance,was developed to predict the macrosegregation of gear steel 20CrMnTi continuously cast by a curved billet caster with size of 160 mm×160 mm,and investigated the effect of final electromagnetic stirring(F-EMS)on the fluid flow,heat transfer and solute distribution in the liquid core of continuously cast steel.The results show that the application of F-EMS eliminates the effect of thermosolutal buoyancy on the asymmetric distribution of carbon concentration in the cross section of billet and accelerates the final solidification of resident molten steel in the liquid core of strand,but promotes the negative carbon segregation near the billet center.When the gear steel 20CrMnTi is cast at the temperature of 1803 K and speed of 1.7 m/min,the solidification end advances forward from 9.84 to 9.72 m,and center carbon segregation ratio of billet decreases from 1.24 to 1.17 with the increase in current density of F-EMS from 0 to 350 A.展开更多
Final electromagnetic stirring(F-EMS)and thermal soft reduction(TSR)are techniques that improve the inner quality of continuous casting billets,but they have rarely been applied simultaneously.The application effects ...Final electromagnetic stirring(F-EMS)and thermal soft reduction(TSR)are techniques that improve the inner quality of continuous casting billets,but they have rarely been applied simultaneously.The application effects of F-EMS and TSR were compared,and a process integrating F-EMS and TSR was adopted for a billet continuous caster.A heat transfer model was established to calculate the thermal behavior of 82A tire cord steel billet.The locations of F-EMS and TSR were determined,followed by conducting a series of plant trials,involving F-EMS alone,TSR alone,and the integrated process of F-EMS and TSR.The results showed that F-EMS or TSR could effectively improve the inner quality of the billet under their respective suitable working conditions.Moreover,F-EMS was found to be more helpful in terms of improving central segregation,while TSR tended to improve V-segregation,central porosity,and pipe.The integration of F-EMS and TSR allowed the advantages of each technique to be utilized,thereby better improving the inner quality.Among all the working conditions,82A steel billet showed optimum inner quality when the current of F-EMS was 240 A and the cooling intensity of TSR was 2.2 m^(3) h^(−1).These findings demonstrate that the integration of F-EMS and TSR is promising for application on continuous casting billets.展开更多
The effect of final electromagnetic stirring on the solidification structure,element segregation,and carbides of GCrl5 bearing steel was investigated.The experiment of continuous casting of the steel was carried out b...The effect of final electromagnetic stirring on the solidification structure,element segregation,and carbides of GCrl5 bearing steel was investigated.The experiment of continuous casting of the steel was carried out by using a continuous casting physical simulation apparatus with the final electromagnetic stirring.The liquid core profile was revealed by the pour-out method during the solidification process.Eight ingots were produced under different electromagnetic stirring parameters for comparison.The results show that,at the final stage of solidification,intense electromagnetic stirring exacerbates the central carbon segregation,resulting in more serious precipitation of the primary carbides.It is also found that the carbides in the segregation area are dominantly M3C type,together with a small amount of M7C3-type and M3C2-type carbides.In this physical simulation model,the optimal stirring parameters to obtain a fine and homogeneous structure are the liquid pool width of 15 mm,current intensity of 150 A,and stirring frequency of 5 Hz.展开更多
基金The authors gratefully acknowledge the financial support of the National Key Research and Development Plan(Nos.2017YFB0304100 and 2016YFB0300105)National Natural Science Foundation of China(Nos.51674072,51704151,and 51804067)Fundamental Research Funds for the Central Universities(Nos.N182504014,N170708020,and N172503013).
文摘A 3D/2D hybrid multi-physical-field mathematical model,which takes into consideration the thermosolutal buoyance,was developed to predict the macrosegregation of gear steel 20CrMnTi continuously cast by a curved billet caster with size of 160 mm×160 mm,and investigated the effect of final electromagnetic stirring(F-EMS)on the fluid flow,heat transfer and solute distribution in the liquid core of continuously cast steel.The results show that the application of F-EMS eliminates the effect of thermosolutal buoyancy on the asymmetric distribution of carbon concentration in the cross section of billet and accelerates the final solidification of resident molten steel in the liquid core of strand,but promotes the negative carbon segregation near the billet center.When the gear steel 20CrMnTi is cast at the temperature of 1803 K and speed of 1.7 m/min,the solidification end advances forward from 9.84 to 9.72 m,and center carbon segregation ratio of billet decreases from 1.24 to 1.17 with the increase in current density of F-EMS from 0 to 350 A.
基金the financial support provided by the independent subject of State Key Laboratory of Advanced MetallurgyUniversity of Science and Technology Beijing,China,grant number 41617003,which enabled the successful completion of the study.
文摘Final electromagnetic stirring(F-EMS)and thermal soft reduction(TSR)are techniques that improve the inner quality of continuous casting billets,but they have rarely been applied simultaneously.The application effects of F-EMS and TSR were compared,and a process integrating F-EMS and TSR was adopted for a billet continuous caster.A heat transfer model was established to calculate the thermal behavior of 82A tire cord steel billet.The locations of F-EMS and TSR were determined,followed by conducting a series of plant trials,involving F-EMS alone,TSR alone,and the integrated process of F-EMS and TSR.The results showed that F-EMS or TSR could effectively improve the inner quality of the billet under their respective suitable working conditions.Moreover,F-EMS was found to be more helpful in terms of improving central segregation,while TSR tended to improve V-segregation,central porosity,and pipe.The integration of F-EMS and TSR allowed the advantages of each technique to be utilized,thereby better improving the inner quality.Among all the working conditions,82A steel billet showed optimum inner quality when the current of F-EMS was 240 A and the cooling intensity of TSR was 2.2 m^(3) h^(−1).These findings demonstrate that the integration of F-EMS and TSR is promising for application on continuous casting billets.
基金the National Natural Science Foundation of China(Nos.U1560202,51604171,and 51690162)the Shanghai Municipal Science and Technology Commission(No.17JC1400602).
文摘The effect of final electromagnetic stirring on the solidification structure,element segregation,and carbides of GCrl5 bearing steel was investigated.The experiment of continuous casting of the steel was carried out by using a continuous casting physical simulation apparatus with the final electromagnetic stirring.The liquid core profile was revealed by the pour-out method during the solidification process.Eight ingots were produced under different electromagnetic stirring parameters for comparison.The results show that,at the final stage of solidification,intense electromagnetic stirring exacerbates the central carbon segregation,resulting in more serious precipitation of the primary carbides.It is also found that the carbides in the segregation area are dominantly M3C type,together with a small amount of M7C3-type and M3C2-type carbides.In this physical simulation model,the optimal stirring parameters to obtain a fine and homogeneous structure are the liquid pool width of 15 mm,current intensity of 150 A,and stirring frequency of 5 Hz.
