The process parameters effect of ovality in cross wedge rolling for hollow valve without mandril

This paper presents the experimental and numerical results of the effect process parameters on ovality in cross wedge rolling (CWR) for hollow engine valve without mandrel. Numerical simulation model for ovality was established by means of the rigid-plastic finite element modeling (FEM) method for hollow engine valve. The experiments and numerical analyses suggest that the following parameters represent the best conditions for CWR of hollow engine valve: 30 degrees-34 degrees for the forming angle(alpha), 5 degrees-7 degrees for the stretching angle(beta), 0.2-0.3mm for the mold void width(L), and 65%-70% for the area reduction(psi).