<p>This study analyzes the pipe bursting accident of S30432 austenitic stainless-steel final stage superheater in a thermal power plant, and reveals the failure mechanism through macroscopic morphology examination, mechanical property testing, metallographic organization analysis, and precipitation phase EDS analysis. The results show that the failure was the result of the synergistic effect of flue gas corrosion thinning (external cause) and metallurgical organization aging (internal cause), and because the high sodium sulfur flue gas from the Zhundong coal induced molten salt corrosion, which led to the local thinning of the pipe wall. At the same time, overheating service prompted the coarsening of a grain boundary precipitation phase, the precipitation of a large number of M₂₃C₆, σ phase, and NbC phase, so that the grain boundary strength decreased, and the material-bearing capacity decreased. At the same time, the temperature of the tube service was calculated, and the fact that the tube safety margin was reduced and the risk of pipe burst was high was verified by calculating the circumferential stress. This study provides a theoretical basis for the selection of heat-resistant steel for ultra-supercritical thermal power units and the safe blending of Zhundong coal.</p>