2020 年 60 巻 9 号 p. 1924-1937
A computational model coupling electromagnetic field with a macroscopic heat and fluid flow is developed to investigate the flow pattern and solidification in a vertical continuous caster using a four-port submerged entry nozzle (SEN) with mold and strand electromagnetic stirring (M-EMS and S-EMS). The flow pattern and solidification features of the bloom strand without and with EMS in the caster using the four-port SEN is analyzed and compared with that using a straight-port nozzle. The effects of the stirring parameters and the position of the strand stirrer on the flow and solidification are discussed. The approach to identify the optimum stirring parameters by the comparison of tangential velocity is suggested. The results show that the application of M-EMS in a four-port SEN can weaken the strength of the jet impingement from every port of the four-port SEN, and rapidly dissipate the superheat of the melt and reduce the liquid fraction in the mold. In spite of inhomogeneous shell growth in the mold, the swirl velocity obtained by a four-port SEN and M-EMS and the solidus fraction by S-EMS is above those of a single-port SEN with the same stirring strength, which is favorable for the formation of more equiaxed crystals. For the S-EMS, the solidified shell thickness is the main factor to determine the stirring position and the tangential velocity at the same stirring intensity. In terms of different ported SENs, it is necessary to perform specific optimization of the stirring parameters of M-EMS and S-EMS.
