不同拉速工艺下连铸板坯横截面中心偏析和夹杂物的原位统计分布分析

Original position statistic distribution analysis of the centerline segregation and the inclusion distribution in the cross section of continuous casting slab under different drawing speed technology conditions

采用原位统计分布分析技术对不同拉速工艺条件下连铸板坯中心横截面的偏析特性和夹杂物分布进行了研究。通过对3.0 m/min和4.2 m/min拉速条件下C,Si,Mn,P,S及Al系夹杂物含量在连铸板坯中心横截面的分布规律对比,发现在低拉速工艺条件下,样品中C,Mn,P等元素在连铸板坯横截面的统计均匀性好于高拉速工艺条件下样品,Si,S等元素则呈现相反的规律,S,P,C等元素易形成“点状”偏析,呈不连续分散分布的特点,Al系夹杂物分布均匀,粒度小;高拉速工艺条件下,样品中S,P,C等元素易形成“带状”偏析,呈连续分布的特点,并位于板厚中心线附近,Al系夹杂物分布不均匀,粒度大,更靠近板坯的上下表面。

The centerline segregation and the inclusion distribution in the cross section of continuous casting slab under different drawing speed technology conditions have been investigated by original position statistic distribution analysis （OPA） technique. By comparing the distribution regularity of C, Si, Mn, P and S as well as the Al inclusion content in the cross section of the slab with two different speeds of 3.0 m/min and 4.2 m/min, it was found that the distribution homogeneity of C, Mn and P in continuous casting slab obtained under lower drawing-speed was much better than that obtained under higher drawing-speed, whereas Si and S presented opposite distribution regularity. At lower drawing-speed, C,P and S were easy to form ＂dot＂ segregation, which was discontinuous and disperse; the distribution of Al inclusion was homogeneous and the granularity was relatively smaller. At higher drawing-speed, C, P and S were easy to form ＂band＂ segregation, which was continuous and lays near to the centerline of the slab. In addition, at higher speed, the distribution of Al inclusion was not homogeneous; the inclusion was near to the upper and down surfaces and the granularity was bigger.