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Elimination of the forging process step in the manufacture of conventionally forged products could reduce overall costs appreciably. For this to be possible, the starting material would have to be clean with respect to non-metallic inclusions and carbide aggregation, and have minimal chemical segregation. The ingot to billet conversion process would have to produce a uniformly fine grained structure with carbide stringers, inclusion content and mechanical properties that would meet forged part requirements. A production ingot of Alloy718 was homogenized and converted to 15" RCS billet by the melter. It was then further processed to three 8" round billets, 135" long each at Wyman-Gordon using a "fine grain" conversion practice. This practice employs controlled reductions and heating times with a decreasing forge temperature ending at 1800'F for the final cosmetic pass. A 2000 T conversion press and flat draw dies were used. After a 1750'F solution and two step age the structure, cleanliness and mechanical properties were evaluated on specimens taken from the top of the top billet, the top of the middle billet and the bottom of the bottom billet, Traverse and longitudinal sections were examined macroscopically and metallographically for grain size, grain flow, presence of stringers and inclusions , precipitated phases, etc. Smooth and notched tensile tests were run at R.T. and lOOOF in duplicate on specimens in the longitudinal, radial and tangential orientations from each of the three billet locations. Creep rupture tests at 1200F were carried out on similarly oriented test bars, Low cycle fatigue tests, strain controlled, were run at 800F in triplicate for the longitudinal and radial orientations of the three billets. Cleanliness and grain structure was very good, with only rare patches of coarser grains at the very surface of the top billet. Occasional carbide stringers up to a maximum of 0.0075" long were seen. Some variation of Ni3Cb precipitate was present, within the normally encountered range in forgings. Tensile strengths and ductilities were good at both temperatures, with notched to smooth U.T.S. ratios always above 1.35. Creep rupture and LCF properties were comparable to those of normal forgings, as well. No significant differences with billet location were found for any of the properties, The longitudinal specimens did tend to exhibit greater Superalloy 71 S-Metallurgy and Applications Edited by E.A. Loria The Minerals, Metals & Materials Society, 1989 189 ductility and LCF life than the others. In summary, cleanliness, structure and properties of these Alloy 718 billets appear to be equivalent to those of conventional forgings.

High Quality, High Strength Alloy 718 Billet Material Using Fine-Grain Conversion Practice