BOF-LF-VD-CC生产37Mn5钢夹杂物的行为演变

为了探究37Mn5钢生产过程中夹杂物的行为演变过程,减少钢中非金属夹杂物的数量,针对国内某钢厂生产37Mn5钢管所采用的BOF-LF-VD-CC工艺流程取不同工位的钢样,分析夹杂物数量、尺寸、成分的变化规律。结果表明,LF出站后的夹杂物类型主要包含两种,MnS夹杂物和MnS-Al₂O₃夹杂物;VD出站后夹杂物多为MnS夹杂物、Al₂O₃-CaO-MgO、Al₂O₃-CaO-MgO-CaS复合夹杂物,夹杂物数密度相比于LF出站下降了21.54%,平均尺寸降低了57.05%,同时夹杂物形状由不规则变为球形,这说明VD有良好的精炼效果。中间包中夹杂物数量增加,可能是由于发生了二次氧化,应选择成分合理的保护渣,提高钢液质量。

Behavior evolution of inclusions in 37Mn5 steel produced by BOF-LF-VD-CC

In order to explore the behavior evolution process of inclusions in 37Mn5 steel production and reduce the number of non-metallic inclusions in the steel,the steel samples at different positions were taken according to the BOF-LF-VD-CC process adopted by a domestic steel plant to produce 37Mn5 steel pipes,and the change rule of the number,size and composition of inclusions was analyzed. The results show that there are mainly two types of inclusions after LF treatment:MnS and MnS-Al₂O₃. Most of the inclusions after VD are MnS,Al₂O₃-CaO-MgO,Al₂O₃-CaO-MgO-CaS. Compared with LF treatment,the number density of inclusions decreased by 21.54% and the average size decreased by 57.05%.The shape of inclusions changes from irregular to spherical after VD,which indicates that VD has good refining effect. Increasing the number of inclusions in tundish may result from secondary oxidation. Mold flux with reasonable composition should be selected to improve the quality of molten steel.