Modeling of the Open-Die and Radial Forging Processes for Alloy 718

To better understand the effects of process parameters on the production of a fine-grained forged 718 billet, and to assist Cytemp in the selection of a new forging machine, a detailed modeling effort was conducted on the processing of 718. The specification of appropriate boundary conditions and material data, and the formulation of the finite element models using DEFORM are discussed. The modeling results revealed, in a qualitative way, that open die forging tends to do more work at the center of the ingot, while radial forging brings about more deformation at the ingot surface. Die shape was identified as an important forging design variable. Curvature at the comers of the die, compared with curvature at the center of the die, resulted in more work at the center of the ingot. Better penetration of work to the center of the ingot also resulted from increasing bite ratios to as high as 0.8 in radial forging. Many of the variables considered had a concomitant effect on the curvature of the end of the ingot. This latter parameter could be used for verification in plant trials, where the kinematic boundary conditions could be carefully monitored. Forging operators and consultants verified that the results reported in this study are qualitatively correct in predicting trends in open-die and radial forging operations. Superalloys 718,625 and Various Derivatives Edited by Edward A. Loria The Minerals, Metals & Materials Society, 1991