Study On The Numerical Simulation Of Mold Filling Process Of Aluminum Alloys Semi-solid Die-casting

As a new near-net forming technology,semi-solid forming technology,which has great processing environment,wide potential application,high production efficiency and excellent product quality,has been more and more widely used in the actual casting process.Aluminum alloy semi-solid die casting is one of the most important technologies in semi-solid forming.However,in the semi-solid die casting process of aluminum alloy,the aluminum alloy semi-solid slurry,which has a certain strength in the process of flow filling,is a solid-liquid phase mixture,which is different from the traditional liquid die casting.The mobility of the relevant physical field in the filling process is difficult to predict,which made the development of the process program difficult.The apparent viscosity model,the discrete solution technique and the filling simulation of the semi-solid die-casting process of aluminum alloy are studied in this paper.The actual die-casting experiment is verified and applied to the actual casting.The final semi-solid forming program can be developed for the technician for reference.Firstly,a mathematical model of semi-solid die-casting process for aluminum alloy is established.Based on the analysis of the characteristics and related mechanism of semi-solid die-casting of aluminum alloy,the apparent viscosity model of semi-solid die-casting of aluminum alloy is established by analyzing the relevant factors affecting the viscosity change of semi-solid filling process.The principle of fluid dynamics and the basic control equation of flow and so on.Coupled aluminum alloy semi-solid apparent viscosity model is established,and a fluid field model based on aluminum alloy semi-solid die-casting process is established.And the physical field boundary conditions in the simulation process are discussed.Secondly,the discrete solution of the mathematical model of semi-solid die-casting filling process of aluminum alloy is completed.Based on the staggered grid technique,the SOLA-VOF method is used to solve the fluid field equation,and the stability conditions of the numerical simulation process are analyzed.At the same time,the semi-solid apparent viscosity model is introduced into the step flow,and the accuracy of the semi-solid apparent viscosity model is verified by comparing the velocity and velocity of the ordinary step flow.Then,the simulation and calculation of the semi-solid die-casting filling process of aluminum alloy are completed.The results show that the filling results of the two kinds of strip castings with uniform distribution are calculated and the results of the filling shape of the castings with different filling stages are studied.Compared with the simulation results of ordinary aluminum alloy die casting,Speed and pressure were compared and analyzed.The experimental results show that the pouring filling quantity of the actual castings is determined by controlling the displacement of the piston distance under the same conditions,and the experimental results of each stage are obtained,which are compared with the simulation results.Finally,the semi-solid die-casting simulation method of aluminum alloy is applied to the actual casting.The semi-solid die-casting simulation method of aluminum alloy is used to analyze the filling flow pattern of the actual castings to determine the rationality of the process and provide the process reference for the semi-solid forming process.