The leakage has occurred on the tube panel of final-stage reheater of boilers in one power plant

and macroscopic inspection

spectroscopic analysis

and metallographic analysis etc.have been carried out.Results show that the cracking at TP304H side of different steel joints is due to complex stress resulted from the grain boundary embrittlement of material

the strength decrease

and the welding deffects

etc..For these

it is recommented to carry out macroscopic inspection

non-destructive detection

and metallographic spot check etc.for TP304 tubes and weld joints in major and temporary repairs

so as to avoid the occurrence of leakage.