连铸异型坯质量缺陷的形成机理与应对措施

Study on the formation mechanism and countermeasures of quality defects in continuous casting beam blank

文中总结了异型坯连铸主要缺陷的形成机理与应对措施。就腹板纵裂纹、圆角处裂纹和表面夹渣方面分析了表面缺陷产生的原因;以中心裂纹、翼缘顶端角部裂纹和气泡的特征说明了内部缺陷的发生机理。对于表面质量缺陷,主要是对钢水成分、冷却方式、保护渣性能等进行优化;对于内部质量缺陷,主要通过调整钢水过热度、拉速、浸入式水口位置等方案进行改良。最后,阐明了异型坯连铸过程需要重点关注的事项。

In this paper,the formation mechanism and countermeasures of the main defect types of beam blank continuous casting are summarized.The causes of surface defects are analyzed in terms of longitudinal cracks of web,fillet cracks,and surface slag,and the occurrence mechanism of internal defects is explained by the characteristics of central cracks,flange tip corner cracks,and bubbles.For the surface quality defects,it is mainly to optimize the composition of molten steel,the cooling mode,and the performance of protective slag;For the internal quality defects,it is mainly improved by adjusting the superheat of molten steel,casting speed,immersion nozzle position and so on.Finally,the matters needing more attention in the process of beam blank continuous casting are expounded.