Abstract：The cleanliness of IF steel first slab produced by BOF-RH-CC and the difference with the cleanliness of normal slab were studied by means of total oxygen and nitrogen content analysis, SLIME, SEM, EDS, etc.. It was found that the T[O] and [N] of first slab were obviously decreasing along casting direction The large-sized inclusions contents of first slab were obviously higher than those of normal slab, and were generally decreasing along casting direction, and were close to those of normal slab after the position of 4.4m along first slab. The distribution of large-sized inclusions was non-homogeneous along thickness direction of slab, which contents of inner arc slab were obviously higher than those of outer arc slab. The size of large-sized inclusions were mainly from 140μm to 300μm and the size over 300μm, which accounted individually for 22.6% and 56.8% of total large-sized inclusions and were from slag entrapment in mould or tundish, reoxidation products and stuffing sand.
2010, Vol. 45 
