Numerical Study on the Influence of the Initial Temperature Distribution on the Material Flow During Die Forging of a Semi-finished Aluminium-Titanium Product

Tailored Forming provides an innovative process chain for manufacturing hybrid components. This study focuses on a process design of a hybrid bearing bushing consisting of aluminium alloy EN-AW-6082 and Titan-Grade-2 or -5 using numerical simulation. The manufacturing process used was a closed die forging process with pre-joined hybrid semi-finished products in a radial arrangement. Due to the simultaneous forming of two different materials, a fundamental knowledge about the flow properties of each material is necessary to achieve a stable forming process. For this, a material characterisation by means of uniaxial compression tests was carried out. The aim was to identify the temperature range in which the flow properties of aluminium and titanium converge. These results were used in a numerical study of the forming process of a hybrid bearing bushing. In a pre-step heating simulation, a suitable inhomogeneous temperature distribution of the hybrid semi-finished product was calculated to achieve the desired temperature field. Subsequently, a numerical study of a closed-die forging process for the manufacture of a hybrid bearing bushing was carried out. A comprehensive stress analysis was carried out to identify a suitable initial temperature distribution to avoid the occurrence of high tangential stresses, which can lead to cracks during the forming process. The results of the presented numerical study will be used in further experimental investigations to improve the presented forming process.