长期高温服役CO转化炉炉管的损伤  

Damage of furnace tubes in CO reformer after long-term service at elevated temperature

作　　者：朱瑞 洑阳成明 浦江[2] 耿鲁阳[1] 唐建群[1] 巩建鸣[1] ZHU Rui;FUYANG Chengming;PU Jiang;GENG Luyang;TANG Jianqun;GONG Jianming(Key Laboratory of Design and Manufacture of Extreme Pressure Equipment, School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211800, China;Special Equipment Safety Supervision Inspection Institute of Jiangsu Province, Nanjing 210036, China)

机构地区：[1]南京工业大学机械与动力工程学院,极端承压装备设计与制造重点实验室,江苏南京211800 [2]江苏省特种设备安全监督检验研究院,江苏南京210036

出　　处：《南京工业大学学报（自然科学版）》2020年第5期586-593,共8页Journal of Nanjing Tech University(Natural Science Edition)

基　　金：国家重点研发计划(2018YFC0808800)。

摘　　要：采用光学显微镜和扫描电子显微镜,对长期高温服役CO转化炉炉管材料HP40Nb合金进行微观组织的观察和相组成的能谱分析,并在900℃条件下对炉管材料的高温力学性能进行测试。结果表明:在长期高温服役过程中,炉管已受到一定程度的损伤。HP40Nb合金晶界上存在单个和链状的蠕变孔洞及微裂纹,沿晶分布的骨架状共晶碳化物逐渐发生分解,形成蠕虫状和块状碳化物,基体中弥散析出二次碳化物。在相演变过程中,部分碳化铌(NbC)转变成富含Ni、Nb、Si的脆性G相(Ni16Nb6Si7),G相转变过程中释放出的C元素与Cr元素结合,使得晶界处的富Cr碳化物(M23C6)数量不断增加并粗化长大。微观组织的改变、G相的形成和晶界处新析出M23C6碳化物的增加,导致材料的高温力学性能发生变化。The microstructures and phase compositions of HP40Nb alloy used in the furnace tubes of CO reformer after long-term service at elevated temperature were analyzed by optical microscope and scanning electron microscope with energy spectrometer,and the high-temperature tensile properties were investigated at 900℃.Results showed that the damage was occurred on furnace tubes to some extent after long-term service at elevated temperature.The isolated and chain-like creep cavities as well as micro-cracks were found at the grain boundaries of HP40Nb alloy used for fabricating furnace tubes.The skeleton-like primary carbides along the grain boundary gradually dissolved into worm-like and blocky structures,and numerous secondary carbides were dispersed and precipitated in the matrix.During the evolution of phases,partial Niobium carbide(NbC)were transformed into brittle G phase(Ni16Nb6Si7)that was rich in Ni,Nb and Si.C element released during the transformation of G phase would be combined with the Cr element to form Chromium-rich carbide(M23C6),which increased the amount of M23C6 in the grain boundaries.The M23C6 carbide would gradually coarsen and grow.The coarsening and growth of newly-developed M23C6 carbide at the grain boundaries and the formation of the G phase would contribute to the changes of the high-temperature mechanical properties for HP40Nb alloy.

关 键 词：炉管 HP40Nb合金 损伤 微观组织 高温力学性能 

分 类 号：TG115.9[金属学及工艺—物理冶金]