Research On Squeeze Casting Process Of The Loading Wheel Based On Numerical Simulation

With the development of science and technology,the world is working hard to develop low-weight,high-performance,high-precision weapons and equipment.The heavy load wheel is a key component of the armored vehicle walking system,which directly affects the weight and performance of the entire armored vehicle.The use of aluminum alloy instead of the original steel material can greatly reduce the weight of armored vehicles,lightweight and improve the operational flexibility of armored vehicles.At present,pressure casting,die forging and squeeze casting are the main methods for productions of the loading wheel.Among them,the squeeze casting has the advantages of casting and forging,less cutting or no cutting of the near-end forming technology.It is suitable for the feeding difficulties,wall thickness uneven parts.The process of forming a small grain size,uniform organization,excellent mechanical properties of the casting and machining a small amount of material,not only to ensure the performance of the product,but also has a good economic performance.Therefore,squeeze casting process has become the first choice of aluminum alloy wheel production.Based on a full understanding of the development of numerical simulation technology during solidification process at home and abroad,the principle and characteristics of squeeze casting process,the mechanics forming process of solidification process under pressure,the heat transfer law of solidification process and so on,this paper uses the ProCAST software to simulate the solidification process of the wheel during squeeze casting process,analysis the changes of temperature field under different pressure and predict shrinkage defect.In combination with domestic squeeze casting equipment and feeding characteristics on the basis of the parts,the way of the squeeze casting is improved and the die design is optimized according to the simulation results.The main research results are as follows:(1)According to the basic theory of solidification heat transfer,the mathematical model of the temperature field is established and the solution is given.It is successfully applied in temperature field simulation and the defects are predicted.(2)The simulations of wheel pressure under different temperature are completed.The results show that the loading wheel gradually is solidified from the surface to the bottom under pressure,but the solidification effect of each part is different.The contact surface between the mold and the mold is the fastest solidification,while the thicker corner is the final solidification area.With the increase of the pressure,the rate of the loading wheel’s solidification is increased rapidly.(3)With the increase of the pressure,the solidification time of the loading wheel’s is shortened.(4)The effect of pressure on the shrinkage and shrinkage was studied.It is found that the increase of pressure can effectively reduce the shrinkages,and the shrinkages disappear when the pressure increases to 100 MPa.(5)The loading wheel’s method of squeeze casting,which is adjusted by the conventional simple pressure for the composite pressure.The numerical simulation of composite pressure shows that the shrinkage porosity is reduced or even disappeared under low pressure.Results of the contrasted experiments show that the tensile strength and elongation of the composite pressurized wheel have reached the standard.It is that mechanical properties of the loading wheel have been in line with the requirements of scientific research project.(6)In this paper,the main process parameters of pouring temperature 730℃,mold preheating temperature 300℃ and holding time 32 S were used in the composite compression of squeeze casting process with the amount of shrinkage of 4mm.The tensile strength σ_b of the loading wheel is 361.5MPa and the elongation δ is 8.18%,which satisfies the mechanical requirements of the project σ_b> 360 MPa,δ> 6%.(7)On the basis of the composite press casting process,the forming mold of the loading wheel is optimized,the temperature control system of the forming mold is developed and the working principle of the equipment such as the heating device,the cooling device and the positioning device is introduced.