Can Design for Nonisothermal Pancake Forging of Gamma Titanium Aluminide Alloys

Abstract

The design of cans to produce uniform, defect-free gamma titanium aluminide alloy pancakes via conventional, nonisothermal forging, was established using finite element modeling (FEM) and laboratory validation trials. The specific problem addressed was ingot breakdown via pancake forging, a process typically comprising a high reduction ratio (∼6:1) and a moderately high deformation rate (∼1 s−1 ) to minimize the effects of die chilling. Can and process variables investigated in the FEM simulations included can end cap shape and thickness, ram speed, and preheat temperature. The FEM results demonstrated that there is an optimal end cap thickness and ram speed to obtain moderately uniform flow between the can and titanium aluminide workpiece. These results were validated through trials on the near-gamma titanium aluminide alloy Ti-45.5Al-2Cr-2Nb forged in AlSl type 304 stainless steel cans.