The Flow Behavior of Molten Steel in an RH Degasser Under Different Ladle Bottom Stirring Processes

The effects of the ladle bottom stirring flow rate and the number of argon plugs on the circulation flow rate and mixing time in an RH degasser were studied using a physical simulation method. The flow field in the RH ladle was studied using particle image velocimetry (PIV). The results show that applying the ladle bottom stirring process has a great influence on the flow field in the RH ladle. When only stirring under the upleg, the circulation of the RH ladle was enhanced. The velocity of molten steel circulation was accelerated, the RH circulation flow rate was increased, and the mixing time was decreased. When the lifting gas flow rate is 133.3 m(3) h(-1) and the ladle bottom stirring rate is 166.7 L min(-1), the circulation flow rate increases by approximately 25 pct, and the mixing time decreases between 36 and 40 pct compared with that without ladle bottom stirring. Stirring in the argon plug below the downleg is not conducive to improving the circulation flow rate but is beneficial to reducing the molten steel mixing time. Double-ladle argon plug stirring can improve molten steel activity on both sides of the snorkel at the upper part of the RH ladle, but this can negatively affect the original vessel circulation. To ensure that the circulation flow is not reduced during double-ladle bottom argon plug stirring, the snorkel upleg lifting gas flow rate must be greater than 133.3 m(3) h(-1) for the system studied in this work.

Automated summary

Research on RH degasser revealed that ladle bottom stirring flow rate and argon plugs quantity greatly impact flow field, circulation flow rate and mixing time. Proper stirring can enhance circulation flow rate and reduce mixing time, but adjustment of gas flow rate is essential.