Basic Research On The Distortion Of Super-Alloy Thin-Wall Blade

Blade is one of the key components of aero engine which plays an important role in energy conversion of the engine. As typical thin-walled structural parts, there also exist many problems in the machining of these blades such as distortion and chatter, which will decrease the machining precision and shorten tool life. In order to work in the environment of high temperature and high pressure, most of the turbine blades are made of super-alloys; their relatively poor machinability, along with the complex surface feature and low rigidity of the blades increase the difficulty of the machining process. The distortion of super-alloy thin-walled blades is studied utilizing experimental approach, simulation method and theoretical analysis and corresponding strategies are put forward. The main research work is as follows:Firstly, two forms of peak milling force predictive models are established based on the orthogonal experiments and their predictive precision are evaluated through relevant experiments. Single-factor experiments are conducted to study the variation of cutting force under different milling parameters. GUI(Graphical User Interface) in MATLAB is designed for fast selection of cutting parameters.Secondly, based on the cutting force predictive model and related experiments, a simulation model of super-alloy thin-walled blade is built. The simulation results of distortion with different parameters and clamping methods are calculated, which is in accordance with the mechanical theory analytical results. Milling experiments of thin-walled blade is conducted using the optimized process techniques, and the result meets the processing requirements.Thirdly, numerical simulation and contour method are combined to study the initial residual stress of the blade after heat treatment process. The results of the two methods show some consistency. Finite element simulation is used to study the effect of initial residual stress on machining distortion.