Research On Material Properties And Life Prediction Of The Remanufactured Aeroengine Turbine Disk

The fatigue failure of aeroengine turbine disk is very serious because of the complexity of structure and service environment,and the turbine disk is expensive,the economic benefits of direct replacement is too low,so it is urgent to repair the failed turbine disk by remanufacturing.Laser additive manufacturing technology is widely used in remanufacturing turbine disk,the quality of remanufactured turbine disk should be guaranteed,at the same time,the service environment of the remanufactured turbine disk is also very bad.Compared with the new product,it is not only affected by the centrifugal force exerted by the blade,the centrifugal stress produced by the mass of the turbine disk itself,the thermal stress produced by the temperature gradient,but also by the influence induced by remanufacturing process.So,in this paper,the performance of Inconel718 specimen fabricated by laser additive technology is analyzed.The material properties are analyzed through hardness test,static load mechanics test and residual stress test.And the stress-strain analysis of remanufactured turbine disk under working stress are carried out by finite element method.Finally,the low cycle fatigue life of remanufactured turbine disk is calculated.Firstly,the technological parameters of laser additive manufacturing for remanufacturing turbine disk are selected.The matrix material is Inconel718 alloy forging and the powder material is Inconel 718 spherical powder.By observing the microstructures of the specimens manufactured with different technological parameters,the appropriate technological parameters of remanufacturing are selected.Inconel 718 thin-walled specimen was fabricated by laser additive manufacturing technology according to the selected process parameters.The hardness test,static mechanical tensile test and residual stress test were carried out,the samples were fabricated by wire cutting and treated by aging heat treatment.The material properties are obtained.Then,the model of remanufactured disk is constructed based on the characteristics of remanufactured turbine disk structure,and the model is meshed by finite element method.The material parameters of Inconel 718 alloy forging and specimens made by laser addition are given.Then the boundary conditions are given for the model of the remanufactured turbine disk.Based on finite element elastoplastic mechanics and calculus principle,the stress and strain of remanufactured turbine disk under several typical working loads,such as blade centrifugal force load,self centrifugal load and temperature load,are analyzed by ABAQUS.The analysis results are used to predict the low cycle fatigue life of remanufactured turbine disk.Finally,the low-cycle fatigue life of remanufactured turbine disk is calculated by Morrow formula.The influence of dangerous parts number on turbine disk fatigue life and the influence of laser additive technology is considered,then the low-cycle fatigue life prediction result of remanufactured turbine disk are modified.