20CrMnTi冶炼过程中夹杂物行为研究

Research on the Non-metallic Inclusion in 20CrMnTi Steel During the Process of Refining and Casting

采用金相观察、扫描电镜（SEM）、电子探针（EDS）和大样电解等手段，对20CrMnTi钢中非金属夹杂物的分布行为进行研究。结果表明：LF精炼促进非金属夹杂物的去除，但浇注过程存在吸气现象，造成铸坯中T[O]和[N]含量分别为18．53×10^-6和46．94×10^-6；铸坯中显微夹杂物体积率较高，为0．085％-0．11％；钢液和铸坯中显微夹杂物主要为氧化物、硫化物、硅钙和钙铝酸盐复合夹杂，是典型的脱氧和脱硫产物；中间包钢液和铸坯中大型夹杂物含量分别达到1．011mg／kg和0．785mg／kg，主要为SiO2类和硅铝酸盐复合夹杂，这些夹杂物中K2O和Na2O含量较高，是典型的含有结晶器保护渣成分的复合夹杂物。

Use the methods of metallographic observation, sample-electrolysing, SEM and EPMA, the quantity, dimension, morphologies and composition of non-metallic inclusions in 20CrMnTi steel were investigated. It was suggested that lots of non-metallic inclusions were removed from molten steel during LF refining. The T[O] and [N] contents in slab were 18.53 × 10^-6 and 46.94 × 10^-6, respectively, as some air could be inhaled into molten steel. The volume ratio of micro-inclusion in slab was being from 0.085% to 0.11%. The micro-inclusions in molten steel and slab, which were typical production during deoxidization and desulfurization, were comprised with oxide, sulfide, calcium silicates and calcium aluminates inclusions. The quantity of large-scale inclusions in molten steel in tundish and slab were 1.011 mg/kg and 0. 785 mg/kg. These typical complex inclusions were silicates and silicate aluminates with higher contents of K2O and Na2O, which were the main components in mold powder.