A numerical simulation of the thermal stress field of the solidified shell in the mold during continuous casting of peritectic steel slab was calculated.The results showed,owing to the volume contraction caused by the...A numerical simulation of the thermal stress field of the solidified shell in the mold during continuous casting of peritectic steel slab was calculated.The results showed,owing to the volume contraction caused by the peritectic reaction,the thermal stress on the wide surface of the solidified shell was larger for the peritectic steel slab than that for the non-peritectic steel,and the maximum thermal stress on the wide face was at the 200-400mm position away from the central line.With increment of slab width,the thermal stress increased and the maximum value moved towards the central line.In addition,the thermal stress was also affected by the casting operation parameters.In the present work,the proper drawing speed was around 1.2m/min for the wide slab of 3200mm×150mm,with the cooling intensity of 5500L/min and the superheat degree of 15℃ to 25℃.展开更多
After the heavy reduction(HR)process was carried out at the solidification end of the continuous casting slab,the austenite grains were refined by recrystallization,which improved the thermoplasticity of the slab.Howe...After the heavy reduction(HR)process was carried out at the solidification end of the continuous casting slab,the austenite grains were refined by recrystallization,which improved the thermoplasticity of the slab.However,the reduction in deformation during the HR process initiated stress concentration at the slab surface,and the crack risk increased.To effectively evaluate the risk of slab surface cracks under these complex conditions,the effect of the HR on the austenite recrystallization and thermoplasticity of a microalloyed slab surface was investigated by 15-pass reduction thermal simulation according to the wide and thick slab continuous casting process.The softening fraction was introduced as a global internal variable to quantitatively analyze various recrystallized re-refined grains.After the critical strain reaches the critical strain of dynamic recrystallization,a variety of recrystallization modes alternately occur.Among them,the contribution rate of dynamic crystallization to the later refinement reaches more than 50%.The contribution rates of static recrystallization and metadynamic recrystallization to grain refinement are almost the same.The thermoplasticity of the slab surface first increases and then decreases with increasing reduction pass.It was verified by transmission electron microscopy that the main reason for the decrease in thermoplasticity is that the dislocation multiplication rate increases,resulting in a sharp increase in stress and a decrease in thermoplasticity.展开更多
基金Item Sponsored by the National Natural Science Foundation of China(51174052)the Fundamental Research Funds for the Central Universities of China(110402009)
文摘A numerical simulation of the thermal stress field of the solidified shell in the mold during continuous casting of peritectic steel slab was calculated.The results showed,owing to the volume contraction caused by the peritectic reaction,the thermal stress on the wide surface of the solidified shell was larger for the peritectic steel slab than that for the non-peritectic steel,and the maximum thermal stress on the wide face was at the 200-400mm position away from the central line.With increment of slab width,the thermal stress increased and the maximum value moved towards the central line.In addition,the thermal stress was also affected by the casting operation parameters.In the present work,the proper drawing speed was around 1.2m/min for the wide slab of 3200mm×150mm,with the cooling intensity of 5500L/min and the superheat degree of 15℃ to 25℃.
基金supported by the National Natural Science Foundation of China(51974078)the Applied Basic Research Program of Liaoning Province(2022JH2/101300002,2022JH25/10200003)the Applied Basic Research Program of Liaoning Province,and the State Key Laboratory of Metal Material for Marine Equipment and Application Project(SKLMEA-K202204).
文摘After the heavy reduction(HR)process was carried out at the solidification end of the continuous casting slab,the austenite grains were refined by recrystallization,which improved the thermoplasticity of the slab.However,the reduction in deformation during the HR process initiated stress concentration at the slab surface,and the crack risk increased.To effectively evaluate the risk of slab surface cracks under these complex conditions,the effect of the HR on the austenite recrystallization and thermoplasticity of a microalloyed slab surface was investigated by 15-pass reduction thermal simulation according to the wide and thick slab continuous casting process.The softening fraction was introduced as a global internal variable to quantitatively analyze various recrystallized re-refined grains.After the critical strain reaches the critical strain of dynamic recrystallization,a variety of recrystallization modes alternately occur.Among them,the contribution rate of dynamic crystallization to the later refinement reaches more than 50%.The contribution rates of static recrystallization and metadynamic recrystallization to grain refinement are almost the same.The thermoplasticity of the slab surface first increases and then decreases with increasing reduction pass.It was verified by transmission electron microscopy that the main reason for the decrease in thermoplasticity is that the dislocation multiplication rate increases,resulting in a sharp increase in stress and a decrease in thermoplasticity.
