Several tests were performed on the burst tubes of No.1boiler in Huaneng Yuhuan Power Plant

such as chemical composition analysis

metallographic structure examination

hardness test

room temperature tensile test

room temperature impact test and energy disperse spectrum analysis(EDS).The results showed that

the tube burst occurred on water wall resulted from short-term overheating.The abnormal working conditions like blocking in water wall tubes or poor water circulation were considered as the basic reason for instantaneous overheating of the water wall tubes.Besides

the over-temperature running of tubes

high content of corrosive element S in coal and reducing atmosphere due to incomplete combustion accelerated the failure of water wall tubes.In order to avoid the similar tube burst problems

appropriate recommendations such as enhancing the operation monitoring and controlling the oxygen and sulfur content in coal into the furnace were put forward.