The secondary refining of molten steel in ladle furnace has been playing an increasing importance role in the production of high quality steel. In the present work, a mathematical model to represent the fluid flow, mixing and inclusions behavior in 150 ton ladle furnace was presented, and during the refining process, the variations of concentration, size and density for non-metallic inclusions in the furnace were predicted. The results show that during ladle furnace refining, the variations of the number density for inclusions with different size were not same. The inclusions with the diameter less than 25 μm decrease during the whole period, however, the inclusions with the diameter more than 25 μm increase during the first stage of the treatment and gradually decrease during the later stage. In 15 minutes, all the inclusions show the decrease tendency, but the decrease rate for the inclusions with smaller size becomes lower. After the treatment of ladle furnace, the inclusions with the diameter more than 50 μm were removed, the number of the inclusions with the size of 30-40 μm was not so much, but the inclusions less than 5 μm still remain in the molten steel. Two-tuyere bubbling shows an advantage over one-tuyere for inclusion removal. The mode of argon bubbling with larger gas flowrate firstly and smaller flowrate lately in ladle furnace is in favor of inclusions removal.
展开▼
