铈对Fe-28Mn-10Al-1C低密度钢中非金属夹杂物的影响

Effect of cerium on non-metallic inclusions in Fe-28Mn-10Al-1C lightweight steel

为了研究稀土铈对Fe-28Mn-10Al-1C低密度钢中非金属夹杂物的影响机理,通过扫描电子显微镜(SEM)、能谱分析仪(EDS)及Image J软件对比分析了稀土处理前后夹杂物的形貌、成分、尺寸和数量,并基于热力学计算阐明了稀土铈对夹杂物的改性机理。研究结果表明,低密度钢中典型夹杂物为AlN和AlN-MnS复合夹杂物,钢中AlN夹杂物较多,尺寸较大,平均直径为3.64μm;向低密度钢中添加(质量分数)0.0019%铈后,夹杂物以球状AlN-Ce_(2)S_(3)、AlN-Ce_(2)S_(3)-MnS、AlN-MnS复合夹杂物和单一AlN夹杂物为主,整体夹杂物数量最少,夹杂物平均直径及长宽比降低,平均直径为3.08μm;向低密度钢中添加(质量分数)0.013%铈后,夹杂物则以球状Ce_(2)S_(3)、附着态AlN-Ce_(2)S_(3)和单一AlN夹杂物为主,夹杂物数量异常升高,1~4μm夹杂物所占比例较大,平均直径为2.52μm。稀土处理可有效细化夹杂物尺寸并改善大尺寸氮化物和硫化物夹杂的形貌特征,未检测到单一MnS及Al_(2)O_(3)夹杂物。此外,通过FactStage 8.0热力学计算软件分析了稀土铈对Fe-28Mn-10Al-1C低密度钢中AlN、MnS夹杂物影响规律、稀土夹杂物的析出行为及演变过程,计算表明,AlN在冶炼温度下即可形成,MnS倾向于异质形核,生成AlN-MnS复合夹杂物;加入(质量分数)0.0019%铈后,Ce_(2)S_(3)以AlN为核心析出形成AlN-Ce_(2)S_(3),钢中硫含量降低,抑制了MnS的析出;加入(质量分数)0.013%铈后,析出大量小尺寸Ce_(2)S_(3)夹杂物。

To study the effect of rare-earth Ce on the formation of inclusions in Fe-28Mn-10Al-1C lightweight steels,the morphology,composition,size and number of inclusions in Fe-28Mn-10Al-1C lightweight steels before and after rare earth addition was analyzed by SEM-EDS and Image J analysis software.The results show that the typical inclusions were mainly AlN and AlN-MnS complex inclusions in the current lightweight steel,and a large number of single AlN inclusion was with an average size of 3.64μm.When 0.0019%Ce(mass percent)was added,the main inclusions were spherical AlN-Ce_(2)S_(3),AlN-Ce_(2)S_(3)-MnS,AlN-MnS complex inclusions and single AlN inclusions,the total number of inclusions was the least,and the average diameter and aspect ratio of the inclusions were decreased.The size distribution of inclusion was the most uniform and the average size was 3.08μm.When 0.013%Ce(mass percent)was added,the main inclusions were spherical Ce_(2)S_(3),AlN-Ce_(2)S_(3)and single AlN inclusions,the number of inclusions increased abnormally,and the inclusions was with an average size of 2.52μm.The rare earth treatment can effectively refine the size of inclusions and improve the morphology of Al_(2)O_(3)and MnS inclusions with a large size,and no single Al_(2)O_(3)and MnS inclusions were detected in the steel.In addition,the precipitation behavior and evolution process of rare earth Ce on AlN,MnS inclusions and the formation mechanism of rare earth inclusions in Fe-28Mn-10Al-1C lightweight steel were calculated by FactStage8.0.The calculation results show that AlN could be formed during the smelting process,and MnS inclusion trend to heterogeneous nucleation.After the addition of 0.0019%Ce(mass percent),Ce_(2)S_(3)inclusion precipitated on the surface of AlN and prevented the formation of MnS inclusion.With the addition of 0.013%Ce(mass percent),a large number of fine Ce_(2)S_(3)precipitated in the lightweight steel.