Numerical Simulation On Composite Forming Process Of Forging Casting And For Car Engine Connecting Rod Blank

The connecting rod is the core component of the automobile engine.In the actual production,not only its quality requirements are high,but also its cost is strictly controlled.At present,most of connecting rod blanks are produced by forging or powder forging processes.These processes have many disadvantages such as too many processes,serious mold wear,and large energy consumption,resulting in high manufacturing costs.Drawing on the advantages of easy molding and forging modification,this paper adopts composite forming process to produce the connecting rod blanks.The finite element software is used to numerically simulate the casting and forging performances in the production process,optimizing the small head of connecting rods?rod shape and related parameters before forging.And the simulations verify the superiority of this process.In addition,the process uses non-quenched and tempered steel,which has the advantages of environmental protection and energy conservation,and improves production efficiency.The main contents and conclusions of this research are as follows:1.The shape of the small head of the closed hot die forging has a great influence on the hot forging forming process of the connecting rod blank.In this paper,two schemes with a solid small head and a small head with a hole are designed.And the analysis of DEFORM-3D software simulation is used.After the forming,as to the solid small head,the stress and strain are unevenly distributed and the phenomenon of tiny skins appears at the inner diameter of the small head.When the scheme of small head with a hole is adopted,the forming load was small,the stress and strain distribution was uniform,and the surface was smooth without metal accumulation.Therefore,it was determined that the small head with a hole scheme was used for the hot forging process of the connecting rod.2.The shape of the connecting rod has a great influence on the hot forging forming process of the connecting rod blank.In this paper,two schemes with a solidshaped body and a groove-shaped body are designed.By finite element software simulation analysis,it is obtained that: When a solid shaped body is adopted,the whole connecting rod has serious burr phenomenon.Stress and strain are unevenly distributed.And the forming effect is not good;When groove-shaped body is adopted,stress and strain distribution is even,and there is no burr on the surface of the connecting rod.Forming quality is also good.Therefore,it is determined that the scheme with a groove-shaped rod is adopted in the process of the connecting rod hot forging.3.The fillet between the head of the connecting rod and the forging temperature have a great influence on the closed hot forging of the connecting rod blank.In this paper,DEFORM-3D simulation software is used to numerically simulate the preforms of the connecting rods with different fillet sizes and different forging temperatures.The optimal fillet sizes are determined as R28 and R22,and the optimal forging temperature is 1050°C.When the parameters above are satisfied,the forming quality of the connecting rod blank is the best.4.According to the structural characteristics of the connecting rod blank and the characteristics of the non-tempered steel 49MnVS3,it is determined that the ordinary sand-type gravity casting is adopted,and water glass sand is selected as the modeling material,which has the advantages of low cost,simple way of preparation,and no pollution.The side-injection and top-injection schemes are designed,and the dimensions of each component and riser of the gating system are calculated.The two casting schemes are numerically simulated by Anycasting simulation software,and the results are analyzed based on the simulation results.The side-injection has better filling and solidification effects and are suitable for the production of connecting rod blanks.5.The influence of pouring temperature and pouring speed on forming quality of connecting rod blank is simulated and analyzed: at 1540~1600°C,the higher the pouring temperature,the fewer the defect of the shrinkage of connecting rod blanks,and the best pouring temperature is 1600°C.Pouring speed determines the distribution of residual air over the surface of the casting.When the pouring speed is 0.7m/s,the volume of remaining air on the top surface of the casting is the smallest,and the forming quality is the best.