Research On Rapid Investment Casting Technology Of Titanium Alloy Impeller

Rapid manufacturing technology of titanium alloy parts is a long-term concern of manufacturing industry.Especially for complex titanium alloy parts which meet the needs of model projects,the research and development cost is high,the cycle is long,and the performance index is difficult to guarantee.It has become a research hotspot of 3D printing technology in recent years.In this paper,the development of foreign marine titanium alloy impellers was carried out to study the rapid casting process.Firstly,around the casting defects of titanium alloy,the numerical calculation softxware was selected to analyze the calculation criterion of defects.Two kinds of gating systems were designed,and the relationship between defect distribution and casting quality was revealed by simulation.In order to ensure the quality of casting,the range of conventional casting process parameters was optimized.A better pouring process scheme was provided for the practice of rapid casting technology.Secondly,the techology of preparing polystyrene prototype by selective laser sintering was studied.The effects of preheating temperature,laser power,scanning speed,scanning distance and layered thickness on the dimensional accuracy of the parts were analyzed by orthogonal experiment method,and the optimum combination of process parameters was determined.Around the casting design requirements,different surfaces were required for the quality of the prototype,and different measures were taken to prepare a prototype that met the process requirements.Finally,according to the optimization results of gating system,the qualified shell was made by the double casting tree scheme.The casting was poured by gravity pouring in the environment with vacuum less than 0.4Pa,and impeller casting was produced by cleaning,cutting riser,hot isostatic pressing and annealing.The results of X-ray inspection and mechanical performance analysis of furnace test rod showed that the casting met the requirements of design standards.The feasibility of rapid investment casting process for titanium alloy impeller was verified.