| Damping alloy parts are widely used in industrial equipment with excellent shock absorption and noise reduction performance.Manganese-based alloy is well known with damping performance,especially with higher Mn content.However,Mn is likely to oxidize and has high vaporization pressure,which means special measurement has to be taken against oxidization during melting and casting process.Therefore,there is an urgent need to develop a near-net-shape preparation process.In this work,the gas-protected investment casting process is used to prepare high-manganese manganese-based damping alloy part,and the preparation process including wax investment and casting are optimized by using Moldflow and ProCAST.In addition,the composition,structure,mechanics and damping properties of the as-cast alloy samples were investigated through various test methods.The alloy damping mechanism was investigated through various test results and theoretical analysis of the alloy.By performing different heat treatments parameters,properties of the alloy,the damping performance,mechanical property and its strengthening mechanisms were studied.The following conclusions are obtained:(1)Based on Moldflow simulation wax injection process,the best process parameters of wax injection were obtained through orthogonal experiments:the temperature of wax injection is 53℃;the time of wax injection is 13s;the time of cooling is 100s;the time of holding is 20s;The pressure of holding is 80%of the maximum injection pressure.The wax mold produced according to this process is of good quality and can be put into production use.(2)Based on ProCAST to simulate the casting process of the parts,the simulation setting parameters are as follows:the thickness of the mold shell is 10mm;the preheating temperature of the shell is 1050℃;the pouring temperature of the molten metal is 1200℃.The simulation results show that castings with good quality can be obtained when pouring under this parameter.According to these parameters,the parts were casted with good quality.(3)The Mn content of the alloy parts prepared by the gas-protected investment casting process is more than 70%,which can effectively solve the problems of severe Mn burning and Mn oxidation,so that the alloy composition reaches the expected standard.At the same time,the as-cast alloy has a uniform structure and stable performance(damping tan?=0.0391,Rm=397MPa,123.5HV).Therefore,the investment casting process of manganese-based damping alloy gas protection can meet the actual production needs of parts.(4)The choice of alloy heat treatment parameters,the solution temperature selects the high temperature end,because the alloy will have a higher supersaturation when the solution is treated at the high temperature end,and there will be a large number of?phases and distribution after the alloy is cooled to room temperature Evenly.The aging selection is carried out in the metastable miscible zone(400℃~600℃)and the low temperature end is selected,because the aging at the low temperature end can make the amplitude modulation decomposition fully proceed,and too high aging temperature will produce?-Mn harmful to the alloy performance phase.(5)The optimal heat treatment parameters of the alloy are 900℃solid solution for 1 hour and water cooling followed by aging at 430℃for 4 hours.The alloy sample under this heat treatment condition has the best performance.At this time,the damping properties,tensile strength,and hardness of the alloy samples were 0.0544,425MPa,and 156.3HV,respectively.Compared with the as-cast alloys 0.0391,397MPa,and 123.5HV,the performance was improved by 39.1%,7.1%,and 26.7%,respectively.The reason is that the amplitude modulation decomposition occurs after heat treatment of the alloy,which makes the Mn content in the Mn-rich region of the alloy higher,the martensite transformation point M_S increases,and more martensite twins exist in the alloy at room temperature,so as to improve damping property. |
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