1.Strip Technology Department of Shougang Research Institute of Technology, Beijing 100043, China 2.Steelmaking Department of Shougang Qian��an Iron and Steel Company, Qian��an 064404, Hebei, China
Abstract��Based on continuous sampling after Al deoxidation during RH refining, the change of cleanliness of molten steel with oval and circle submerged tubes respectively was studied. The results show that removal rate of inclusions with oval submerged tube is higher than that of the circle submerged tube. The main inclusions in steel after Al deoxidation are Al2O3 inclusions, which present different morphologies at different time. When the cycle time reaches 1min after Al deoxidation, the shape of Al2O3 inclusions is cluster and the size is over a few hundred microns��when the cycle time reaches 2 min, the type and shape of inclusions don��t change, but the size reduces to tens of microns; when the cycle time reaches 6 min, the type of inclusions don��t change, but the shape of inclusions is single and globular and the size is less 10��m. Besides, the number density of inclusions obviously decreases with the increase of cycle time and reaches to the lowest level in the case of 4min after Al deoxidation.
2018, Vol. 30 
