Optimization Of High Temperature Alloy Grain Refiner Mechanical Processing Research

It is primary important to control the grain structure in many solidification processes of casting, because the grain structure has influence on their mechanical properties and operating performances. Optimizing refiner about fine grain casting of superalloys basing on Neural Network, change of temperature fields of solidification and the influence of grain refinement to machinability have been studied in this paper.Firstly, grain size and dendrite morphologies of superalloy are investigated after appending three metallic compounds, A,B and mixstrure of A,B, grain of casting have been studied in different melting pouring temperature and melting homogeneous temperature. Analyzing the result of experiments of refinements by Neural Network module, the outcome shows that the proper dose is approximately 0.4wt% whether one kind of refiner or more, the grain size of castings can be refined obviously by lowering the melting pouring temperature and the melt homogeneous temperature. And adding compound, made up of Cr , Nb, Fe, and Co , can be benefit to refine the grain size in the case of not changing the composition of the alloy. At the same time, the grain size of refiners can also influence the grain refinements of castings and the appropriate grain size of refiners is about 30μm. When pouring temperature is 1530℃, grain tissue of superalloy casting would minish to micron grade through adding refiner of Optimizing.In order to realize the solidification of superalloy and optimize investment casting process, the change of temperature of columner and thin shell castings have been analyzed in this paper. Contrating to column casitng ,Thin shell castings, the change of cooling point temperature in the link about two shell is slower 71 % than other points, the time of solidification becomes longer, and the size of grain will be bigger. This is according with the practice.Secondly, in this paper, the influence of different grain size to machinability of Superalloys was studied .The main tasks of this paper were studying the change of grain microstructure and machinability of superalloys after grain refinement. Two things have been done to test working properties of different grain samples. One is testing the force of milling, the other is testing the roughness of the milling surface. The outcome of this experiment revealed that after grain refinement the milling force of sample reduced over 50 percent ,the roughness reduced from 3.135μm to...