70钢连铸坯中非金属夹杂物的来源及控制

Study on Non-Metallic Inclusion in 70 Steel Continuous Casting Billet

应用光学显微镜和电子探针分析方法,对70钢连铸坯中非金属夹杂物的形貌、大小、数量、组成和来源进行了研究,旨在降低钢中非金属夹杂物的含量,提高钢材质量。结果表明,铸坯中5μm以上的夹杂物主要为形状不规则的脱硫产物Ⅲ型硫化锰,其次为复合脱氧产物铝硅酸盐和凝固前沿形成的铁氧化物,以及少量脱氧产物与熔蚀耐火材料形成的球状铝酸盐或含镁铝硅酸盐,研究结果为优化70钢连铸坯生产工艺提供了依据。

The amount, size, morphology, composition and source of the inclusion in 70 continuous casting billet werestudied by means oI optical microscopy and electron probe mlcroanalysis （EPMA） to lower the amount ot non-metal inclusion and to increase the quality of steel. The results show that the III-MnS in irregular shape is main inclusions larger than5 μm in continuous casting billet, then the composite aluminates by deoxidizing products and the FeO precipitated inthe front of steel solidification, and a few globular compound aluminates reacted with refractory MgO or A12 03.The study could be useful to optimize the produetion technology of 70 continuous casting billet.