Finite Element Simulation of Non-Isothermal Warm Forming of High-Strength Aluminum Alloy Sheet

This paper examines non-isothermal warm forming experiments on AA7xxx-series channel sections at two different initial blank temperatures (187 and 253 degrees C) with room temperature tooling. Supporting non-linear thermo-mechanical finite element simulations are performed, considering multiple stages comprising heating of the blank, transfer to the press, forming, dwell in die and cooling in air to room temperature. Elevated Twist Compression Tests are performed for the lubricant Forge Ease AL278 which allows characterization of friction coefficient as a function of temperature. Based on attached thermocouples during forming, thickness measurements and recorded force-stroke curves, the simulation model is validated. Furthermore, micro hardness measurements on the formed rail are performed to study the effect of heat exposure on the material strength.