Research On Composite Technology Of Cross Wedge Rolling (CWR) And Forging For The Automobile Drive Shaft Fork

The universal joint fork of the transmission shaft is a key transmission component in the transmission mechanism of the vehicle,which conveys all the driving forces of the vehicle.The working environment is extremely poor,the load is heavy.In addition,the high using intensity and high toughness are required.The universal joint fork is a kind of fork-type part,which is difficult to forming.The technological feasibility,stability,material utilization,and how to reduce load,improving the service life of the mold are the questions that must be considered during the forming process of the universal joint fork.Therefore,a new technology of combination CWR and forging to produce the fork is presented which has advantages of high material utilization,high efficiency and low cost.In this paper,DEFORM-3D simulation and wedge rolling-die forging experiment are combined to systematically study the process of combination CWR and forging for universal joint fork of Automobile drive shaft.The parameters of cross wedge rolling die were determined as forming angle of 27 degrees,broadening angle of 9 degrees and section shrinkage_of 55%.Through the finite element simulation,the metal flow rule,stress and strain,of the blank in the process of CWR and die forging deformation can be obtained.In the process of die forging,the deformation of the big end begins at first,and the largest deformation occurs at the final bifurcation,followed by the corner,and the smallest deformation occurs at the bottom of the big end.Besides,the average grain size and dynamic recrystallization volume fraction were studied so as to measure the deformation uniformity of the blank quantitatively.In addition,the influence law of process parameters on forming force in die forging process is analyzed.Three factors and three levels orthogonal experiments are designed by using the experimental design method to optimize the process parameters.The optimized process parameters were obtained: the temperature of 1100℃,the friction factor of 0.2,and the falling speed of the upper die of 150mm/s.Then,on the basis of optimization,the finished product of joint fork was produced through CWR and die forging experiments.The size and shape of the finished product were basically consistent with the simulation results,which verified the feasibility of the processing technology and the reliability of simulation.In addition,metallographic microstructure test,microhardness test and tensile strength test were carried out to test the mechanical properties of the joints.The results showed that the average error of grain size of fork products produced by rolling and forging between experimentals and simulation results was less than 3.72%,and the average grain refinement degree at the large end,corner and fork was 47.69%,70.45% and 78.47% respectively.In the same way,the hardness was increased by 54.15%,83.87% and 49.13% respectively.The application of composite technology of cross wedge rolling(CWR)and forging for the automobile drive shaft fork can greatly improve the comprehensive mechanical properties of finished products,increase the production efficiency by 4-5 times,increase the utilization rate of materials by 30%,and increase the economic benefit of a single production line by 9.63 times annually.