Deformation mechanism and performance improvement of spline shaft with 42CrMo steel by axial-infeed incremental rolling process

In this paper, a novel axial-infeed incremental rolling process of spline shaft with 42CrMo steel is proposed to solve the problems of present manufacture process. The principle of the axial-infeed incremental rolling process is introduced firstly, and then the deformation mechanism is analyzed by finite element method (FEM). The numerical results show that the deformation and material flow during the novel process only occurs in the surface layer of the blank, and the metal flow velocity component along the radial direction is significantly higher than that along the axial direction. Next, the experimental research is carried out on axial-infeed incremental rolling equipment, and the microstructure and hardness of the products are evaluated. The experimental results show that the microstructure in the surface of tooth profile, and root is fibrous tissue which is continuous, dense, and streamlined, and the hardness of the tooth profile and root area obviously increases.