Control and prediction of oxidation layer spalling in supercritical power boiler tubes

For the problem of oxide layer spalling caused by corrosion in supercritical power plant boiler tubes, which can lead to blockage of steam flow and even boiler tube burst accidents, this paper adopts a high-temperature oxidation stress growth model to calculate the scaling stress change and spalling time of boiler tubes, providing a basis for the prevention of corrosion and oxide layer spalling in boiler tube walls. The study found that the growth stress of the oxide layer varies parabolically with its thickness. When the growth stress reaches the critical strain of the oxide layer/metal substrate system, the oxide layer spalls. The shutdown and startup temperature differences of the boiler have a significant effect on oxide layer spalling, and a temperature difference control of 4-14°C/min is less likely to cause oxide layer spalling.