The surface coating of the moving blade in the first stage of a gas turbine peeled off

and fatigue cracks occurred at the trailing edge adapter R. To solve thiese problems

failure analysis was performed

and the failure mechanism was discussed. Firstly

investigations were carried out on the failure blades

including the visual observations

material composition analysis

and microstructure analysis. Then

the temperature field and stress field distribution on the blade was simulated. The results show that

sulfur and vanadium in heavy oil will form sulfates and vanadates after combustion

due to local high temperature

these sulfates and vanadates passes through the gap in the ceramic insulation layer and reacts with the material

thus making the surface coating peel off. The high temperature region obtained by CFD analysis is consistent with the spalling region of coating. The results obtained by mechanical simulation show that

the stress level is high at the tailing edge

and fatigue cracks occurr at the tailing edge adapter R by frequent start and stop. Based on the research results

the dominant fatigue mechanism in the root is concluded to be corrosion-fatigue

and reasonable suggestions are put forward for the use of turbine blades.