Aiming at the leakage problem of the front wall superheater during the deep peak shaving and low-load operation of a 600 MW supercritical unit

it is analyzed through methods such as macroscopic morphology

microstructure and mechanical properties. The results show that when the peak load operates below the critical load

the period and amplitude of the wall temperature pulsation of the superheater tubes in the front wall increase significantly. The pulsating over-temperature operation of the heating surface tubes in the area with high heat load leads to an increase in the creep of the outer diameter of the heating surface tubes

spheroidization of the material structure

deterioration of performance

and eventually tube bursting. Therefore

when the unit operates under conditions below the critical load for deep peak shaving

the pulsating over-temperature of the superheater tubes in the cladding wall is the main cause of leakage. It is suggested that the safety and adaptability assessment of the materials for deep peak shaving boilers be further carried out

and the operation mode be optimized in a targeted manner.