炼钢

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超低碳钢连铸坯厚度方向大尺寸夹杂物分布特征

  

  1. (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)
  • 接受日期:1900-01-01 出版日期:2016-04-05

Characterization of large inclusions along the thickness direction in the ultra-low carbon steel slab

  • Accepted:1900-01-01 Online:2016-04-05

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70 mm×80 mm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0.001 2 %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30~100 μm,少数在100 μm以上,这些夹杂物在铸坯厚度1/4处呈现更明显的聚集。

关键词: 超低碳钢, 夹杂物, 三氧化二铝, 气泡, 连铸坯

Abstract: 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 20-200 μm 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.

Key words: ultra-low carbon steel, inclusion, alumina, bubble, continuous casting slab