An experimental study for open die forging of heavy ingots was carried out using physical modeling. In order to verify the validity of the experimental data, similarity study between plasticine and AISI4130 has been made. According to the experimental results, the material property of plasticine at room temperature was similar to the one of AISI4130 at 1000℃. Using the plasticine, the forging experiments with flash were carried out. Various cylindrical billets with different aspect ratios were forged and different flash width to thickness(W/T) ratios were used in order to determine the optimum forging conditions. As W/T ratios decrease forging load decrease while excess volume increases. Open die forging was divided into several stages for dome TYPE(1)&(2) of AISI4130 since the required forging load is larger than the capacity of the forging pressures which was assumed to be $100kg_f$ in the presents conditions. As a result of these experiments, it was found out physical modeling is an excellent tool for forging process design at practical level.
