After cooling in the hot rolling process,the metallographic structure of microalloyed dual-phase steel is nonuniform along the rolling direction,while the thickness fluctuation of microalloyed dual-phase steel with a ...After cooling in the hot rolling process,the metallographic structure of microalloyed dual-phase steel is nonuniform along the rolling direction,while the thickness fluctuation of microalloyed dual-phase steel with a nonuniform metallographic structure will occur during cold rolling.The mechanism of nonuniform phase transformation of microalloyed dual-phase steels was studied during the cooling process after hot rolling,and the nonuniform phase transformation of microalloyed dual-phase steel was regulated during the cooling process after hot rolling through process optimization.First,the empirical equation of phase transformation temperature was measured by a dilatometer considering thermal expansion.Then,the phase field and temperature field of laminar cooling process were calculated to provide initial boundary conditions for the finite element model.After that,the coupling finite element model of the temperature phase transformation of the strip steel in coiling transportation process was established.The simulation results show that the different thermal contact conditions of the microalloyed dual-phase steel during coil transportation lead to uneven cooling of the coil,which leads to nonuniform transformation of the coil along the rolling direction.In addition,by prolonging the time interval from coiling to unloading,the phenomenon of nonuniform phase transformation of microalloyed dual-phase steel can be effectively controlled.The simulation results are applied to industrial production.The application results show that prolonging the time interval from coiling to unloading can effectively improve the nonuniform phase transformation of microalloyed dual-phase steel in the cooling process after hot rolling.展开更多
We study the multistability of fixed points for a dimerized system of Rydberg atoms driven by two laser fields and trapped in a two-dimensional(2D)square lattice.For identical driving fields,the fixed points of this s...We study the multistability of fixed points for a dimerized system of Rydberg atoms driven by two laser fields and trapped in a two-dimensional(2D)square lattice.For identical driving fields,the fixed points of this system exhibit stable uniform,unstable uniform,stable nonuniform,or oscillating nonuniform phases in the presence of a bistable region.For different driving fields,however,all(stable,unstable,or oscillating)phases become nonuniform instead,which then results in two islets isolated from the mainland of Rydberg excitation.We also show that a tristable region may stretch out from the(nonuniform)bistable region near the islets,indicating that a richer phase diagram can be attained by tuning the Rabi frequencies and/or detunings of the driving fields.Last but not least,the fixed points can adiabatically evolve from the islets to the mainland but can not inversely evolve from the mainland to the islets.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.52004029).
文摘After cooling in the hot rolling process,the metallographic structure of microalloyed dual-phase steel is nonuniform along the rolling direction,while the thickness fluctuation of microalloyed dual-phase steel with a nonuniform metallographic structure will occur during cold rolling.The mechanism of nonuniform phase transformation of microalloyed dual-phase steels was studied during the cooling process after hot rolling,and the nonuniform phase transformation of microalloyed dual-phase steel was regulated during the cooling process after hot rolling through process optimization.First,the empirical equation of phase transformation temperature was measured by a dilatometer considering thermal expansion.Then,the phase field and temperature field of laminar cooling process were calculated to provide initial boundary conditions for the finite element model.After that,the coupling finite element model of the temperature phase transformation of the strip steel in coiling transportation process was established.The simulation results show that the different thermal contact conditions of the microalloyed dual-phase steel during coil transportation lead to uneven cooling of the coil,which leads to nonuniform transformation of the coil along the rolling direction.In addition,by prolonging the time interval from coiling to unloading,the phenomenon of nonuniform phase transformation of microalloyed dual-phase steel can be effectively controlled.The simulation results are applied to industrial production.The application results show that prolonging the time interval from coiling to unloading can effectively improve the nonuniform phase transformation of microalloyed dual-phase steel in the cooling process after hot rolling.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11534002 and 11674049)
文摘We study the multistability of fixed points for a dimerized system of Rydberg atoms driven by two laser fields and trapped in a two-dimensional(2D)square lattice.For identical driving fields,the fixed points of this system exhibit stable uniform,unstable uniform,stable nonuniform,or oscillating nonuniform phases in the presence of a bistable region.For different driving fields,however,all(stable,unstable,or oscillating)phases become nonuniform instead,which then results in two islets isolated from the mainland of Rydberg excitation.We also show that a tristable region may stretch out from the(nonuniform)bistable region near the islets,indicating that a richer phase diagram can be attained by tuning the Rabi frequencies and/or detunings of the driving fields.Last but not least,the fixed points can adiabatically evolve from the islets to the mainland but can not inversely evolve from the mainland to the islets.
