SPHC板卷表面缺陷来源示踪研究

通过在SPHC钢生产的不同工位添加示踪元素来追踪表面缺陷夹渣的来源。结果表明,在中间包覆盖剂内检测到钢包渣示踪元素Ba,可见有明显的下渣现象;各工位电解得到的大型夹杂物中,LF精炼中含有大量的Ba,而在中间包和连铸坯内Ba含量相对较少,LF内有明显的卷渣且在后续工序中有明显的上浮去除,在中间包和铸坯内均有少量的检测到中间包覆盖剂示踪元素Sr和中包包壁示踪元素La,可见中包有包壁侵蚀和覆盖剂卷入现象;得到的缺陷样中,58.33%缺陷样含有Na和K,25%含有Sr,含Ba和La的数量较少,可见结晶器保护渣和中间包覆盖剂为缺陷的主要来源;通过对缺陷的成分分析,得出其他的夹渣来源可能为脱氧产物。

APPLICATION OF TRACERS TO INVESTIGATE SOURCE OF SLAG INCLUSIONS IN SURFACE DEFECTS OF SPHC STEEL

Trials for adding tracers in different procedures were performed to investigate the source of slag inclusions in SPHC steel. Results showed that,among macro- inclusions by electrolysis in different procedures,a large amount of Ba,which were added in LF refining slag,were detected in macro- inclusions of LF refining,while very small in tundish and continuous casting slab. It was demonstrated that slag- entrainment occurred in LF refining and then removed by flotation significantly in follow- up process; A few tundish cover flux tracer element Sr and the tundish linings tracer La were detected in tundish and continuous casting slab,so there were slight wall erosion and slag- entrainment in tundish. 58. 33% of the defect samples were detected element Na and K,25% were detected element Sr,and samples detected element Ba and La were a few,which could be concluded that mould flux and tundish cover flux contributed significantly to the generation of the slag inclusions. Through analyzing the compositions of defects,deoxidization products probably were the secondary source of other slag defects.