Cause Analysis on Tube Explosion of Finishing Superheater in a Supercritical Circulating Fluidized Bed Boiler

By means of macroscopic inspection, chemical composition analysis, metallographic examination, mechanical property test, fracture analysis and energy spectrum analysis, the causes for the tube explosion of the finishing superheater in a supercritical circulating fluidized bed boiler were analyzed. The results show that the type of the tube explosion was stress corrosion cracking, and the stress which mainly came from the thermal expansion stress due to the thermal unbalance during operation and the welding residual stress of the fillet weld, was the main factor for the tube explosion. Finally, relevant preventive measures were put forward.