Cross-wedge rolling of a 4Cr9Si2 hollow valve: explorative experiment and finite element simulation

Cross-wedge rolling (CWR) has many advantages in the production of shafts and rolling while a hollow valve is widely used in engine production. In this study, we use the CWR process to produce a hollow valve made of 4Cr9Si2 steel and present the experimental results. To evaluate the CWR process and deeply understand the deformation characteristics, a 3D finite element model (FEM) of the CWR process is established, and the mechanism of material flow, the temperature distribution, and the strain and rolling force are analyzed. The following conclusions are drawn based on the experiments and numerical simulations: changing the stretching angle ( β ) can effectively avoid swollen holes; the forming quality of the workpiece can be greatly improved when the forming angle ( α ) is equal to 35° and the stretching angle ( β ) is equal to 5° and 4° in the knifing and stretching zones, respectively; the CWR process is an effective technique to manufacture hollow valves for industrial production.