Numerical Simulation And Process Optimization Of Squeeze Casting Process

The different filling state and solidification sequence of the alloy will influence the macroscopic defects and microstructure of the casting,thus affecting the properties of the casting.Therefore,it is necessary to understand and master the filling and solidification process of the alloy,so that the process parameters can be well adjusted,the filling and solidification state of the alloy can be controlled,and the macroscopic defects and microstructure of the alloy can be effectively improved.However,the casting process of alloy is complex and opaque,the forming process can be observed clearly and intuitively by computer simulation.The distribution of velocity field,temperature field and microstructure are compared and the process parameters are adjusted to determine more reasonable process parameters,and the experimental cost and trial production cycle are reduced.In this paper,Procast software is used to simulate the squeeze casting process of cupshaped parts.The velocity distribution in the filling process and the temperature distribution in the solidification process are analyzed,the microstructure of the castings is simulated and compared with the experimental microstructure.On the basis of the numerical simulation of the cup-shaped part,the squeeze casting process plan of the aluminum alloy brake clamp is formulated,and the structural size of the casting mold are determined.Then,the forming process of the casting is simulated,and the process plan is optimized according to the defects in the results.Finally,the effect of different process parameters on the microstructure of the casting is analyzed.The results show that the punch speed has a great influence on the axial filling speed of the billet in the squeeze process of cup-shaped part,and the greater the downward speed of the punch,the more uneven the change of the speed in the axial direction.Because of the different size and position of the squeeze force,the solidification time of different parts of the side wall of the cup-shaped part be different,and the last solidification part of the side wall of the cupshaped part is the lower part of the middle part.The average grain size of the simulated microstructure is 56.3um,which is close to the average grain size of 51.5um obtained from the confirmatory experiment,and the experimental result is basically consistent with the simulated microstructure.It is determined that the squeeze method of aluminum alloy brake caliper is indirect extrusion,the forming direction of the casting is vertical,and the method of curved surface parting is adopted.The ingate is located at the bottom of the cylinder,and the overflow groove is located at the upper end of the clamp body.The forming die of brake caliper is designed,including two concave mold modules on the side and a core at the upper end of the cylinder.The pouring temperature of 700 ?,the mold preheating temperature of 300 ? and the squeeze force of 90 MPa are determined by orthogonal experiment.Numerical simulation and process optimization are carried out for the set process scheme,and the filling speed is determined to be regulated in stages.The punch speeds of the first,second and third stages are 100mm/s,15mm/s and 45mm/s,respectively.The squeeze pressure is increased to 130 MPa,and the overflow groove is added to the clamp body bolt.The influence of process parameters on the solidification structure of the alloy is studied,the higher the pouring temperature,the larger the average grain size;with the increase of extrusion force,the grains are refined;and the Ti element in the alloy can also refine the solidification structure of the casting.