Abstract: Abstract:The pipe burst accident of 220 t/h boiler hightemperature superheater of a power plant occurred. For the samples of the burst pipe and the pipes around it, the macroscopic inspection, the test of strength of extension, the hardness measurement and the metallographic analysis were carried out. Combining with practical operation of the hightemperature superheater, comparing with the test result, a comprehensive analysis was done, and it was found that the main reason of the pipe burst is longterm overtemperature of the pipes. Aiming at this situation, the suggestions on subsequent work were proposed to ensure the boiler to operate safely and stably.

Key words: Keywords:hightemperature superheater, pipe burst, longterm overheating, spheroidization, overtemperature, strength of extension