Finite Element Analysis On Filling And Thermal Stress Of Superalloy Hollow Blade Investment Casting

This paper select the turbine hollow blade that was made of the material K488 as the research object, studied the change of temperature field of blade in the process of filling and solidification process, while the stress and deformation of blade were simulated, and optimize the process. Final, the turbine hollow blade was actual casting to verify the simulation results.The 3-D model of the turbine hollow blade has been built by UG, and discussed the interface model between the Geo MESH that the software of mesh division and UG. The file format of igs was selected as the interface mode to the Geo MESH and find out a way to mesh the complex casting, compared the characteristics between Geo MESH and MeshCAST in surface mesh process. Then, we find that the Geo MESH have more advantage on the surface mesh process than MeshCAST. The surface mesh that was handled in the Geo MESH can successfully generate the volume mesh in MeshCAST, and the final grid can satisfy the simulation of backward position very well.Studied the effects of different casting process on casting quality, the results show that when the casting speed is reduced, preheating the temperature of pouring and shell and core can reduce the shrinkage cavity. When the casting speed is reduced to the 2kg/s, the temperature of shell and core are increased to 1100 ℃, the pouring temperature of molten metal is 1480℃,we can obtain the casting without shrinkage cavity. At the same time, we obtain the change of temperature field of casting and core and can output the curve of the temperature with the time change in this process. From the curve, we can see that the temperature of exhaust edge of turbine hollow blade drop fastest, followed by the leading edge and the back of blade, while the temperature of the basin of the turbine hollow blade drop slowest, but the cross grid in core that close to the tenon sustain the highest temperature.The effects of different casting process on the cooling rate of castings in different parts and the body displacement are investigated. The results show that increase the preheating temperature of shell and core, or increase insulation material on the outside of the casting can reduce the temperature difference between the various parts of the casting, but it can also reduce the blade deformation of the turbine hollow blade. In comparison with the displacement of the transverse section of the blade body in the X direction, we can find that the displacement of the middle part of the blade is the lowest, and the displacement of the basin and the leading edge of the blade is lower than that of the back and the exhaust edge of the blade.After preparation of the core, wax mold, and then the shell making, dewaxing, shell sintering and so on a series of crafts, the complete shell have finished. The turbine hollow blade was casted of the material K488 that was melted in the vacuum melting furnace through optimal process of the computer simulation. Also we obtain the complete casting and the blade meet use requirements after testing.