摘要
某电厂高温再热器出口联箱排空气管管座角焊缝在检修期间发现裂纹缺陷,经挖补处理运行约6000h后再次开裂,发生蒸汽泄漏。通过宏观检测、光谱检验、硬度检验、金相检验、扫描电镜分析,得出管座角焊缝再次开裂的原因是补焊工艺不当,存在熔合不良等焊接缺陷,且排空气管穿过包墙处结构设计不合理,使排空气管膨胀受阻,在应力作用下,外壁产生裂纹,沿熔合线向热影响区扩展撕裂。提出了尽快对管座整体进行重新焊接并优化排空气管穿孔结构的建议。
There was a crack on the fillet weld of the ventilation tube of the outlet header socket of a high-temperature reheater in a power plant which was found during maintenance.The tube cracked again and the steam leaked after 6 000 h ours operation since the tube patching.Though macroscopic examination,spectral examination,hardness test,metallographic examination and scanning electron microscopic analysis,reasons for the crack are found out to be the improper repair welding which cause incomplete fusion and and other welding defects.Unreasonable structure design makes the expansion of ventilation tube hampered by the enclosed wall.Weld on the outer surfaces cracks under stress,and the crack spreads along the fusion line to the heat affected zone.It is suggested that the whole socket should be re-welded as soon as possible and the perforation structure of ventilation tube should be optimized.
作者
邓辉
DENG Hui(China Datang Corporation Science and Technology Company Limited,Central-China Electric Power Test Research Institute,Zhengzhou 450000,China)
出处
《华电技术》
CAS
2019年第8期74-77,80,共5页
HUADIAN TECHNOLOGY
关键词
高温再热器
补焊
融合不良
焊接缺陷
裂纹扩展
膨胀受阻
应力
high-temperature reheater
repair welding
incomplete fusion
welding defects
crack propagation
expansion impediment
stress
