Finite element analysis on axial-pushed incremental warm rolling process of spline shaft with 42CrMo steel and relevant improvement

In this paper, we firstly discussed the principle and deformation characteristic of axial-pushed incremental rolling process of spline shaft, and then, an axial-pushed incremental warm rolling process of spline shaft with 42CrMo steel is introduced and studied to investigate the formation mechanism and analyze the effects of process parameters. In order to improve the accuracy of finite element simulation, the plastic flow behavior and constitutive characteristic of 42CrMo steel during warm forming process are studied through the isothermal warm compression tests, and then, the microstructure of tempered sorbite and high-accuracy constitutive equations of 42CrMo steel are obtained. Next, the effects of die angle and deformation temperature on forming load and tooth-filled quality during axial-pushed incremental warm rolling process are analyzed based on finite element analysis (FEA). The optimum die angle of the entrance section and warm forming temperature are determined as 8 and 700 °C, respectively. To verify the results of simulation, the corresponding experiments are carried out on the warm rolling equipment, which is designed by the authors. Finally, the relevant improvement by tooth divided flow method (TDFM) is raised to eliminate the negative effect of blank diameter on this process.