Circulation characteristics of RH degassing vessel water model with multi-legs

Abstract

RH degassing vessels having one up-leg and one down-leg have been used for secondary refining of molten steel. One of the causes that determine their lives is the melting of the firebrick on the side surface of the lower vessel, which is induced by the slag infiltration into the brick. To increase the life of the vessel, the authors have proposed an RH degassing vessel with arranged four legs on the bottom of the lower vessel. A down-leg is positioned at the center and three up-legs are arranged around the down-leg. Both the circulation characteristics and the floating behavior of the slag have been examined using a water model with four legs (proposed model). The slag behavior was simulated using colored plastic particles. To induce water circulation, the air was blown into the up-leg. The results were compared with those of a water model with two legs (conventional model). (1) In the conventional model, the side surface of the lower vessel restricts the water inlet into the down-leg. In the proposed model, the water flows uniformly into the down-leg because of the down-leg position. (2) The circulation flux (i.e. the water circulation rate per unit area of the up-leg) in the proposed model was not less than that in the conventional one. In both models, the circulation flux is increased as an increase in the blowing air rate. (3) In the proposed model, the slag gathers the central part of the surface of the water in the lower vessel.