稀土Ce对T91耐热钢组织及力学性能的影响

Effects of Rare Earth Ce on Microstructure and Mechanical Properties of T91 Heat-resistant Steel

对不同稀土Ce加入量的T91耐热钢进行室温拉伸和冲击性能测试,采用SEM和EDS进行组织观察和断口研究。结果表明,加入稀土Ce能细化晶粒,改变钢中夹杂物的形貌和大小,从而有效改善T91钢的强度与韧性;韧窝中形成的细小球状稀土硫氧化物夹杂是力学性能转变的主要原因;稀土对改善室温冲击性能作用显著,稀土Ce含量在0.0020%时,试样室温冲击性能最佳。

The microstructure and fracture morphology of T91 heat-resistant steel with different content of rare earth Ce were studied by tensile testing and impact testing at room temperature by SEM and EDS. The results show that the morphology and size of the inclusions in T91 heat-resistant steel changes distinctly by adding Ce. The spherical rare-earth oxysulfide inclusions in the dimples are the main factors. Adding rare earth can improve the impact properties at room temperature significantly. The transverse impact value is best at room temperature with the content of 0.0020% Ce.