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研究了添加0.15％混合稀土对Cr18Ni18Si2奥氏体不锈钢高温蠕变断裂强度、塑性及断裂机制的影响。蠕变试验结果表明:含有稀土的Cr18Ni18Si2钢在650—750℃不同应力下的蠕变断裂时间比未加稀土的钢延长约1—4倍,700℃1000h的蠕变断裂应力增加约2kgf/mm~2,断裂塑性增加0.2—2倍,蠕变裂纹及断口的金相和扫描电镜观测结果表明:稀土有强化Cr18Ni18Si2钢晶界、改变断口形貌、阻碍晶界裂纹形成和扩展的作用。
The effect of 0.15% rare earth addition on creep rupture strength, ductility and fracture mechanism of Cr18Ni18Si2 austenitic stainless steel at high temperature was studied. The creep test results show that the creep rupture time of Cr18Ni18Si2 steel containing rare earth is about 1-4 times longer than that of non-rare earth steel at 650-750 ℃, and the creep rupture stress increases by about 2kgf / mm at 700 ℃ for 1000h ~ 2, the fracture plasticity increases by 0.2-2 times. The observation of creep crack and fracture by metallography and scanning electron microscope shows that the rare earth can strengthen the grain boundary of Cr18Ni18Si2 steel and change the morphology of the fracture and hinder the formation and propagation of grain boundary cracks.