Failure Analysis of High Temperature Super-heater Bend for Boiler

Fracture analysis of U-type bend of TP347H tube in the high temperature super-heater of a 1 900 t/h boiler operated for less than 1 000 h was carried out by means of examinations of microstructune,mechanical properties and scanning electron microscopy.The corrosion sensibility of cold-formed TP347H steel increased because solution heat treatment was not performed and the bend was operated under the conditions of high temperature and ash deposits.Intergranular stress corrosion cracking occurred at the position of stress concentration.