125MW机组锅炉前隔墙省煤器进口联箱角焊缝区域失效故障诊断和延寿技术研究

Failure Diagnosis and Life Extension Research for Fillet Weld on Front Partition Economizer Inlet Header of 125 MW Boiler

从锅炉结构、金属试验、无损检测、高温应变测试、有限元应力计算几个方面，对浙江省１２５ ＭＷ机组锅炉前隔墙省煤器下联箱角焊缝处在运行若干年后频繁爆泄的失效情况，进行故障诊断，并提出通过降低结构最大应力达到延寿目的的技改方案，验证性实测证明其具有良好的降应力效果。

Bursting-leakage failures of fillet weld on front partition economizer inlet header of 125 MW boilers occur frequently after 125 MW units have operated for many years.Such kind of failures on 125 MW units in Zhejiang Province were analyzed and failure diagnoses were conducted in terms of boiler structue, metal test, nondestructive inspection, high temperature strain testing and finite element stress calculation.Based upon the analyses and diagnoses, the technic improvement scheme to reduce maximum structural stress so as to extend operating life was put forward.The field test executed on the improved structure showed the effectiveness of reducing stress.