Content of T [O]、[N] and the type,size,quantity,distribution of microinclusions in Q235 steel produced with 120 t BOF-Ar Blowing-CC process at an iron and steel plant in Northern China have been studied with system.The results showed that the average w (T [O]) in casting billet was 78.6 × 10-6,the average w ([N]) was 52.1 × 10-6,and the amount of microinclusions was 11.2 in each square millimeter.The type of micro-inclusions was SiO2-Al2O3-MnO-TiO2-MnS compound inclusion whose particle size was in the range of 2.5 μm to 15 μm (inclusions of 0-5 μm accounted for about 25.01％,inclusions of 5-10 μm accounted for about 43.69％,inclusions of 10-15 μm accounted for about 9.47％).The amount of micro-inclusions reached its maximum in a quarter to a third of the inner and outer arcs,while less in the edge and center of casting billet.Micro-inclusions of the ladle slag pollutants in slab was accounted for 41.2％,and the tundish slag pollutants was 23.3 ％.Adsorption capability for inclusions of ladle slag and tundish slag was poor.Calcium aluminate slag washing of material should be put in the ladle slag to enhance the capability.%系统分析了我国北方某钢厂采用120 t BOF→Ar Blowing→CC工艺生产的Q235钢中氧氮含量、钢中显微夹杂物类型、尺寸、数量及分布的变化历程.结果表明,铸坯中w(T[O])平均为78.6 ×1O-6,w([N])平均为52.1×10-6,显微夹杂物数量为11.2个/mm2;显微夹杂物以SiO2-Al203-MnO-TiO2-MnS复合夹杂为主,粒度在2.5～15 μm之间,其中0～5 μm的夹杂约占25.01％,5～10 μm的夹杂约占43.69％,10～15 μm的夹杂约占9.47％;显微夹杂物在距内外弧1/3 ～ 1/4处含量最高,边部及中心部位夹杂物较少;铸坯中含钢包渣污染物的夹杂占41.2％,含中间包渣污染物的占23.3％.钢包渣、中间包渣对夹杂物的吸附能力明显不足,出钢过程中应加钙铝酸盐基渣洗料对钢包顶渣进行改质,从而降低钢中夹杂物数量.
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