摘要:
系统分析了IF钢铸坯中大型夹杂物的类型、来源、组成和数量以及影响铸坯洁净度的主要因素。结果表明:连铸头坯中的T[O]、[N]含量分别为82.5×10-6和61.5×10-6,其T[O]、[N]含量均明显高于其他连铸坯;铸坯中的大型夹杂物主要有块状Al2O3夹杂物、Al2O3·TiOx类夹杂物、保护渣卷入造成的钛的钙(铝)硅酸盐类夹杂、钙(镁)铝酸盐类夹杂三种类型;二次氧化、中包覆盖剂、保护渣及引流砂是夹杂物的主要来源;大型夹杂物平均含量最高的是头坯3.287 mg/kg,其次是尾坯2.739 mg/kg,然后是混浇坯15.57 mg/kg,正常坯中大型夹杂物含量为12.27 mg/kg;铸坯中的大型夹杂物在厚度方向分布不均匀,铸坯内弧侧夹杂物含量均明显高于外弧侧含量;头坯试样中大型夹杂物主要是粒径140~300μm和大于300μm两类,分别占到了夹杂物总数的38.3%和61.7%。
Abstract:
In this paper,comprehensive analysis had been carried on the macro inclusion with regard to the type,source,composition and quantity and the main factors influencing the cleanliness of casting slab had been identified. Composition analysis shows that the [O] and [N] contents of the first slab are 82.5 ×10-6and 61.5 × 10-6,respectively,both are significant higher than these of other slabs; and the inclusions are mainly divided into three categories: block and cluster of Al2O3,compound Al2O3·TiOx and CaO（SiO2） ·Al2O3·Ti inclusions,which come from re-oxidation products,slag entrapment in mould or tundish,and stuffing sand. First slab has the highest content of macro inclusions with average value of 3.287 mg / kg,followed by the last slab （2.739 mg / kg） and the mixed casting slab （1.557 mg / kg）,while the content of macro inclusions of the normal slab is 1.227 mg / kg. the distribution of macro inclusions is non-homogeneous along thickness direction of slab,where contents of inner arc slab are obviously higher than those of outer arc slab. Macro inclusions comprise of small particle with size of 140~300 μm and large particle bigger than 300μm in first slab,which account for 38.3% and 61.7% of total inclusions,respectively.
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