Mathematical modeling of the motion of convective flows of the melt in a single-flow tundish of a modern micro-plant while providing a refining effect

Processy litʹâ, 2021, Tom 143, №1, p.19-27

Abstract

UDK 621.74.047

Mathematical modeling solved the problem of modeling the motion of convective flows of the melt in single-flow tundish used in modern metallurgical micro-plants.For comparative evaluation of metal receiver designs from the point of view of the refining effect, an element simulating the motion of 
non-metallic inclusions was added to the developed model of convective flow in the tundish. The number, size, and density of non-metallic inclusions were set as the initial data. The introduction of non-metallic inclusions in the liquid bath of the tundish was carried out through a protective tube directly into the incoming portions of the metal. The number of non-metallic inclusions was 120 units. The main dimensions of non-metallic inclusions: 25 μm – 30 units, 50 μm – 30 units, 100 μm – 30 units, 150 μm – 30 units. It is established that the maximum refining effect is achieved when using a metal receiver with beveled side walls towards the nearest narrow wall of the tundish and which has no board. Such design features and method of installation provide a rational for the emergence of non-metallic inclusions trajectory of circulating flows. Despite this, the optimal in the opinion of the authors is the design of the metal receiver with beveled side walls in the direction of the nearest narrow wall of the tundish which has a board. It has a second indicator of the efficiency of removal of inclusions at the level of 87.5 %, but the nature of the flow in the tundish when using it is more optimal. This is due to the fact that the flows coming out of the metal of the receiver are partially extinguished by its structural protrusion - the board, which provides less impact on the lining of the nearest narrow wall of the tundish. Also, by reducing the height of the metal board of the receiver to the range of 20-30 mm, it is possible to increase the efficiency of removal of non-metallic inclusions by more than 90%. At simultaneous use of the metal receiver and a threshold favorable conditions for the prevailing movement of streams of metal in the top part of a liquid bath are created. Due to this, favorable conditions are provided for the emergence and assimilation of non-metallic inclusions by cover slag. It is found that the preferred location of the threshold is a distance of approximately 1/3 of the distance between the axis of the glass-dispenser and the axis of the jet falling from the steel ladle from the side of the glass-dispenser. With this mutual arrangement of the threshold and the metal receiver, the efficiency of removal of inclusions from the tundish is 97.5 %. This figure is the maximum for all studied options.