摘要
某电厂亚临界机组锅炉末级过热器管子在运行过程中发生泄漏,通过宏观分析、化学成分分析、硬度测试、金相检验、扫描电镜及能谱分析等方法,对管子泄漏原因进行了分析。结果表明:该过热器管子长期处于超温运行状态,碳化物在晶界处聚集,呈球状分布,基体碳含量降低,硬度、高温屈服强度、持久强度下降,蠕变速度加快,在管子外表面萌生纵向蠕变裂纹,裂纹扩展导致该末级过热器管子断裂泄漏。
The final superheater tube in a subcritical unit boiler leaked during running.The leakage causes were analyzed by means of macroscopic analysis,chemical composition analysis,hardness test,metallographic examination,scanning electron microscope and energy spectrum analysis and so on.The results show that the superheater tube was in long term over-temperature operation state,and the carbides were clustered at grain boundaries and spherically distributed.The carbon content of the matrix decreased,and the hardness,high temperature yield strength and creep rupture strength also decreased.The creep rate was accelerated,and longitudinal creep cracks were initiated on the outer surface.Crack propagation led to fracture and leakage of the final superheater tube.
作者
李宪爽
LI Xianshuang(Material Research Institute of Harbin Boiler Company Limited,Harbin 150046,China)
出处
《理化检验（物理分册）》
CAS
2019年第1期56-58,共3页
Physical Testing and Chemical Analysis(Part A:Physical Testing)
关键词
末级过热器
泄漏
超温运行
球状碳化物
蠕变
final superheater
leakage
running at over-temperature
spheroidal carbide
creep
