稀土Ce对铸造Cr30Mo2超级铁素体不锈钢组织与力学性能影响

Effects of cerium addition on solidification structure and mechanical properties of Cr30Mo2 super ferritic stainless steel

摘要:

研究了不同Ce含量对铸造Cr30Mo2超级铁素体不锈钢组织与力学性能影响。结果表明，Cr30Mo2超级铁素体不锈钢中夹杂类型主要为富Cr氧化物和Al-Si复合氧化物，且形状不规则，加入Ce后转变为Ce2O3和心部富Al、Si，外层富Al、Ce的圆球状复合夹杂，尺寸较小，形状圆润，夹杂含量显著降低；Ce2O3可以作为异质形核核心，增加铸件形核率，减小晶粒尺寸，但Ce含量过高，晶粒尺寸反常增大；Ce可显著改善Cr30Mo2超级铁素体不锈钢的室温塑性，添加0.07%Ce能将Cr30Mo2超级铁素体不锈钢铸件的断后延伸率由1.5%提高至20%左右。

Abstract:

The effect of different Ce content on the microstructure and mechanical properties of Cr30Mo2 superferrite stainless steel was studied. The results show that the inclusion types in Cr30Mo2 superferrite stainless steel are mainly Cr oxides and Al-Si composite oxides with irregular shapes, which are converted into Ce2O3 after Ce addition and spherical composite inclusions rich in Al and Si in the core and Al and Ce in the outer layer, with small size, round shape and significantly reduced inclusion content. Ce2O3 can be used as heterogeneous nucleation core, which can increase casting nucleation rate and reduce grain size. However, excessive Ce content results in abnormal increase of grain size. Trace Ce can significantly improve the plasticity of Cr30Mo2 stainless steel at room temperature. Adding 0.07%Ce can increase the elongation after fracture from 1.5% to about 20%.