Finite Element Modeling for Hot Forging Process of AISI 4340 Steel

摘要

Hot forging is a common, but important manufacturing process in metal forming industries. Forming at high temperature, flow stress of material decreases and thus lower load is required. Furthermore, mechanical properties of material regarding its microstructure characteristics can be improved according to heating and cooling conditions. Hot forging process for a spacer wheel made of steel AISI 4340 was investigated by means of FE simulation. Initially, hot compression test was performed using a thermo-mechanical simulator for determining flow curves. Different temperatures and strain rates within the process range were considered. A Zener-Hollomon parameter was applied to describe the experimentally obtained flow curves. To verify accuracy of the FE simulations, multi-step hot compression test was carried out at different forming temperatures. Subsequently, force development and final shape calculated for the investigated part were analyzed. Reliability of the FE results was significantly influenced by the defined flow curve or hot deformation behavior of material.