石油套管用37Mn5钢非金属夹杂物的特征研究

Study on the Characteristics of Non-metallic Inclusions in 37Mn5 Steel for Oil Casing Pipe

对新天钢联合特钢有限公司炼钢厂冶炼的37Mn5钢在各个工序中全氧、氮含量以及显微和大型非金属夹杂物的特征进行了研究。结果表明,LF精炼后氧含量降低了约31.34%,非金属夹杂物的含量降低了18.89%,采用LF精炼的方式对钢液中的非金属夹杂物的去除呈现出显著的效果。在中间包和铸坯内含有较多的包含La、Ce元素的非金属夹杂物,说明在中间包和结晶器内存在严重的卷渣现象。从示踪元素所占比例来看,结晶器保护渣卷渣是铸坯中大型夹杂物的主要来源,其次是中间包覆盖剂、钢包渣和中包包衬,其比例约是66︰44︰37︰14。做好保护浇铸,防止二次氧化是控制37Mn5钢非金属夹杂物的主要手段。

The characteristics of total oxygen,nitrogen content,micro and large non-metallic inclusions in 37Mn5 steel produced by Tianjin New Tiangang United Special Steel Co.,Ltd.were studied.The results show that the oxygen content after LF refining is reduced by about 31.34%,and the content of non-metlic inclusions is reduced by 18.89%.LF refining has a significant effect on the removal of non-metallic inclusions.There are many non-metallic inclusions containing La and Ce elements in the tundish and slab,indicating that there is a serious slag entrapment phenomenon in the tundish and mold.From the proportion of tracer elements,slag entrapment of mold flux is the main source of large inclusions in slab,followed by tundish covering agent,ladle slag and tundish lining,and the proportion is about 66:44:37:14.Protective casting and preventing secondary oxidation are the main means to control non-metallic inclusions in 37Mn5 steel.