超低碳钢连铸坯厚度方向大尺寸夹杂物分布特征  

Characterization of large inclusions along the thickness direction in the ultralow carbon steel slab

作　　者：周萌[1] 姜敏[1] 苑鹏[1] 李伟[2] 张学辉[2] 王新华[1] 

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]武汉钢铁股份有限公司炼钢总厂,湖北武汉430083

出　　处：《炼钢》2016年第2期60-63,68,共5页Steelmaking

摘　　要：为减少超低碳冷轧汽车板表面质量缺陷，对直弧形连铸机生产的超低碳连铸坯沿厚度方向不同深度截取70mm×80mm大尺寸金相试样，采用ASPEX explorer自动扫描电镜对大尺寸夹杂物分布特征进行了研究，得到夹杂物的成分、数量、尺寸与分布特征。结果表明，在铸坯w（T．O）降至0．0012％时依然存在较多大型夹杂物，绝大多数为簇群状Al2O3，部分伴生有钢液凝固时析出生成的TiN；其余为少数“气泡＋Al2O3”夹杂物，其尺寸均在30～100μm，少数在100μm以上，这些夹杂物在铸坯厚度1／4处呈现更明显的聚集。To decrease the surface defects on cold rolling sheets caused by inclusions, large inclusions in ultra-low carbon steel slab produced by bending vertical caster were characterized in details along the whole thickness direction. Metallographic samples with large section dimension of 70 mm×80 mm were specially prepared, and the inclusions were inspected by the automatic secondary electron microscopy ASPEX explorer. It was found many large inclusions still exist even T. O mass fraction in slab was reduced to 0.001 2 %. Most majority of them were alumina clusters within 20 - 200μm and the others were the ＂bubble ＋ Al2O3＂ type with big sizes in the range of 30 - 100 μm and some were larger than 100 μm. While the well-known mold-flux entrapped inclusions were not detected. These large inclusions were not only in the surface/subsurface but also located deeply in the slab, indicating an obvious quarter-band accumulation especially for the ＂bubble ＋ Al2O3＂ inclusions.

关 键 词：超低碳钢 夹杂物 三氧化二铝 气泡 连铸坯 

分 类 号：TF777[冶金工程—钢铁冶金]