Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2009.2174.2179ZadshakoyanM.JafarzadehH.112009911In this study, the effects of some die geometry parameters such as: relative gap height, die corner radius and friction coefficient on the forming load and material flow were studied by simulation work. The numerical analysis of the injection forging process was performed in two cases: case I, forcing a cylindrical billet against a flat die and case II, forcing the same billet by moving both the upper and the lower dies in opposite directions. The work piece material was AISI 1006 steel and the simulation work was performed by the rigid-plastic finite element method. The validity of the simulation results obtained in this study was verified by using the experimental data reported in the literature. When comparing the forming load obtained from simulation study and experimental data, the effect of die geometry parameters such as relative gap height, die corner radius, friction coefficient on forming load and material flow were presented. The simulation results show the effectiveness of gap to billet diameter ratio (s/d) on forming load in each two cases. The separation height decreases in case I, when increasing (s/d). In case II, by increasing (s/d) the flange angle and diameter increase too. Effect of decreasing the separation height, when increasing friction coefficient in case one is significant, where friction coefficient is 0.3, the separation height is near the zero.]]>Altinbalik, T. and Y. Can,2006Balendra, R. and Y. Qin,2004Balendra, R. and Y. Qin,2000Balendra, R. and Y. Qin,2004Choi, H.J. and H. Choi,2001DEFORM-2D Software User Manual,2005DuKo, B., D. Kim, S. Hyung and B.B. Hwang,2001Kobayashi, S. and T. Altan,1989Lee, Y.S., S.K. Hwang, Y.S. Chang and B.B. Hwang,2001Qin, Y.I. and R. Balendra,1998