摘要
某超临界参数直流锅炉高温过热器出口三通在累计运行近5?104h后发生泄漏。对该失效三通进行解体,采用宏观检验与微观组织观察、力学性能检验、有限元蠕变应力分析等方法,开展裂纹观察分析、材质性能评价,并结合厚壁三通的生产工艺进行原因分析。研究结果表明:三通本体、主裂纹附近及相邻管均未出现明显的长时蠕变空洞、组织严重老化等特征,无明显因运行导致的组织过热特征,强度校核满足设计要求。主裂纹直管肩部过渡区内壁内凹带处启裂,并向外壁扩展。该裂纹在三通热挤压成型过程中形成,在服役过程中进一步扩展直至断裂失效。
The tee of superheater header outlet of super critical DC furnace leaked after operation for 5 × 10^4h. The normal mechanics test, macro-and micro-structure research, finite element analysis of creep stress, etc were employed to investigate the tee failure mechanism. The systematic research was applied for the failure tee. It shows that there are no creep cavities and microstructure aging characters near the crack of tee body and adjacent pipe. Stress assessment meets the design requirements. The cracks were formed on the tee molding process. And cracks propagated during the tee operation. The study results have some theoretical and engineering significance for life management of power plants.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2014年第14期2307-2313,共7页
Proceedings of the CSEE
关键词
超临界机组
主蒸汽管道
三通
裂纹
微观组织
强度
失效分析
super critical units
main steam pipes
tee
crack
microstructure
strength
failure analysis
