摘要
利用光学显微镜、扫描电镜、能谱仪、拉伸及冲击试验机等对服役15a的制氢转化炉中HP40Nb钢炉管的显微组织和力学性能进行了研究,依据高温持久试验结果估算了炉管剩余寿命。结果表明:长期高温服役后,炉管钢组织中晶界粗化并有G相析出,晶内二次碳化物析出明显,近内壁、近外壁和基体中均出现蠕变孔洞,近内壁和近外壁发生氧化和贫铬,外壁形成脱碳层;与原始铸态炉管相比,长期高温服役后炉管的室温抗拉强度降幅超30%,高温抗拉强度降幅约18%,室温冲击功下降明显,剩余寿命不足1a。
The microstructure and mechanical properties of HP40 Nb steel furnace tube in a hydrogen reformer after 15-year service were studied by optical microscope,scanning electron microscope,energy dispersive spectrometer,tensile and impact testers.Based on the high-temperature creep rupture testing results,the remnant life of the furnace tube was evaluated.The results show that after the long-term high-temperature service,in the microstructure of furnace tube steel,the grain boundaries coarsened with the G phase precipitation;secondary carbides precipitated in grains obviously;creep voids were observed near inner and outer wall and in matrix;oxidation and chromium depletion were observed near inner and outer wall;decarburization layer was formed on the outer wall.Compared with the as-cast steel furnace tube,the tensile strength of the furnace tube after the long-term high-temperature service reduced by 30% and 18% at room and high temperature,respectively,the impact energy at room temperature decreased significantly,and the remnant life was less than 1a.
出处
《机械工程材料》
CSCD
北大核心
2017年第6期49-54,共6页
Materials For Mechanical Engineering
基金
基金项目:CAP1400核电站运行和维护技术研究(2015ZX06002005)
