Effect Of Creep Damage On Steam Oxidation Behavior Of TP347H

With the rapid development of the economy,China's electricity consumption has increased year by year.In order to reduce pollutant emissions and save energy in thermal power plants,vigorously developing high-performance,high-parameter ultra-supercritical units will become the trend of national development of electric power construction.Compared with the subcritical unit,the steam pressure and steam temperature of the supercritical unit are significantly improved.Among them,the high temperature corrosion and high temperature steam oxidation of the steam tube of the power station boiler are more serious due to the high parameters,and the metal pipeline is in the actual service process.In the middle,the surface material is oxidized,and the interior undergoes the interaction of mechanics and high temperature,and under various stresses,the surface oxide layer undergoes the process of fctgrowth-peeling-regeneration'n.Therefore,in the process of regrowing the new oxide layer after the surface oxide scale is peeled off,the characteristics of the new surface in contact with the steam and the underlying layer of the surface layer are completely different from the original materials of the aged.Therefore,it is necessary to study the characteristics of the vapor oxidation properties of metal materials after creep damase.In this paper,the effect of creep damage on the high temperature steam oxidation performance of TP347H austenitic steel was studied.Irn order to characterize the influence of creep damage on its steam oxidation,steam oxidation experiments were carried out under the conditions of equal duration and other conditions for creep damage and creep-free damage,and the metallographic analysis and oxidation of the matrix before oxidation were carried out.The oxidation kinetics,oxide film surface morphology and oxide film cross section were compared for microscopic features.By analyzing the vapor oxidation characteristics of creeping and creep-free materials,it is found that the TP347H material with creep damage is significantly faster than the TP347H material without creep damage;and the cracking and spalling of the oxide layer is obvious;The inner oxide layer has poor adhesion to the substrate,and obvious holes and cracks appear,which provide an outward diffusion channel for the metal ions.