Research On Numegical Simulation And The Preform Optitmization Of Connecting Rod Powder Forging

Connecting rod is an important part of automobile engine,the realization of its lightweight design and the production quality has important influence on improving the performance of engine.Powder forging technology combines the advantages of powder metallurgy and precision forging process which can produce connecting rod with good performance,light weight and low cost,so the connecting rod produced by powder forging has good prospects for application in the background of car production tends to be stable and the pursuit of quality and lightweight.At present,the domestic engine connecting rod mostly for steel forgings,powder forged rod mainly dependent on imports,so the independent research and development of the connecting rod powder forging is helpful to enhance the level of the automobile industry in our country.The deformation of powder forging process is complex,the traditional experimental methods can not accurately and easily understand the deformation and deformation regularity of the material,and the cost is high and the cycle is long.Therefore,it is of great significance to study the influence of forming process and process parameters on the forming quality and the optimization of the preform design with the help of numerical simulation technology.In this paper,the forging process of a certain type of powder forging connecting rod was studied.Then a reasonable simulation geometry model of powder forging connecting rod was established with UG and the typical process parameters and heat-transfer process were determined according to the actual production situation.The density,density uniformity,temperature field,load,stress and strain fields were analyzed,the densification laws of powder forging rod were drawn,and the design defects of the preform were founded.Based on FEM software DEFORM,the average relative density,density change of feature points,effective stress and temperature of the connecting rod were studied in powder forging.The influence laws of forging speed,initial relative density of the preform,forging temperature,die temperature and friction coefficient on the compactness and homogeneity were obtained.And the best combination of process parameters of powder forging were given.Through comparative study on preform with different process and different initial relative density,the forming laws of ring preform were analyzed in upsetting and closed-die forging.The densification law of uniform and non-uniform density distribution of preform which include cylindrical,circular and square preform were explored.The density compensation in different density difference was analyzed which offered reference for the preform design.According to the defects of powder forging connecting rod and the densification laws of the typical preform,there were two kinds of optimizations of perform which were non-uniform density distribution and reduce transverse movement of the small end.Through comparative study on density change of the small end dense order of the feature points,the optimizations improved the compactness and homogeneity of the connecting rod.The results of density measurement showed that the density distribution of the preform was consistent with the optimization plan,so the non-uniform density distribution was reasonable and feasible.