Multi Physical Field Numerical Simulation And Structure Improvement Of Tundish For Blank Billet Continuous Casting

Continuous casting tundish is an important equipment to connect the ladle and the mold. It is the last part of the casting. The flow of molten steel in the tundish directly influences the purity of the molten steel, the quality of the cast slab and so on.Compared with the conventional slab tundish, the tundish has more stringent requirements, and the consistency of the pouring nozzle is very important to the quality of the slab.In this paper, a steel billet continuous casting tundish is used as the research object.At first, through the establishment of molten-steel flow, heat transfer and inclusion motion three-dimensional mathematical model in tundish, and by means of computational fluid dynamics software CFX, the original flow in tundish of the temperature and the flow field of multi field coupling conditions were analyzed. After analysis, there is a serious short circuit flow in the original tundish, and the dwell time of the molten steel is too short, so the structure of the tundish is needed to be improved. Then, put forward the preliminary improvement on the structure,installation of turbulence inhibitor under the nozzle in the tundish. After the installation of turbulence, the flow condition has improved, but there are still some problems such as casting inconsistency, the structure of the tundish need to be further improved,Choosing the proper porous baffle wall, and using orthogonal design method to determine the suitable for the tundish of the porous wall parameters, the rise-angle is 15°, 35°, the horizontal-angle is 30° and the aperture is 80 mm.Finally,the flow field, temperature field and stress field of the improved tundish are analyzed.The result shows,in the improved tundish, the residence time and the response time are all good, the outlet temperature tends to be consistent, which can meet the production requirements, but the erosion of molten steel at the bottom of long nozzle increases. The center of bottom of the turbulence inhibitor is subjected to the maximum stress.Through the improvement of tundish, the residence time of molten steel is prolonged, the response time is increased, the removal rate of inclusions is improved,and the pouring of each nozzle is consistent,leading to the improvement the quality of billet.The research of this paper provides the theoretical support for the internal structure design of the tundish, which has important guiding significance to the production practice.