科研之友
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摘要
A top-swirling turbulence inhibitor(TI) was proposed to generate a rotating velocity filed of molten steel in the tundish impact zone,which could effectively weaken the strength of molten steel returning to steel-slag interface,reduce the turbulent kinetic energy,avoid slag entrapment and secondary oxidation of molten steel,so as to purify the molten steel in the impact zone. To validate the metallurgical superiority of the designed top-swirling TI in each tundish operation periods,the multiphase flow behaviors in a single-strand slab tundish during steady-state casting,start-up operation and ladle changeover process with different TIs (without a TI,with an ordinary TI and with a top-swirling TI) were compared and analyzed by water model experiments. The results showed that the top-swirling TI had no negative effect on the flow field at steady-state casting of tundish,while revealed obvious metallurgical advantages at the transient casting periods. Compared with the case of without a TI,when using the top-swirling TI,the average residence time of molten steel was prolonged from 308.5 s to 327.4 s,and the volume percent of dead zone was reduced from 9.67% to 4.13%,and the response time was increased from 69 s to 109 s,which would effectively avoid the occurrence of short-circuit flow. The exposed areas of molten steel under the cases of without TI and with ordinary TI were about 115 cm2and 55 cm2during start-up operation,and the exposed area were about 90 cm2and 50 cm2during ladle changeover,respectively. While the molten steel would not be exposed to air when using the designed top-swirling TI during both start-up operation and ladle changeover process,and it could effectively reduce the fluctuation of the steel-slag interface compared with the ordinary TI. The top-swirling TI can effectively improve the flow state of molten steel in the tundish,avoid slag entrapment and secondary oxidation of molten steel during transient casting periods,improve the steel cleanness and metal yield,and ensure remarkable service life without obvious cost increasing,which possesses high value of promotion and application. ? 2023 Chinese Society for Metals.
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