Analysis and optimisation of 6XXX aluminium alloys billets homogenisation in monodirectional furnaces

The surge in demand for lightweight materials in automotive applications has positioned aluminum 6xxx extrusions as a key solution, necessitating high-quality aluminum billets. Concurrently, there is a pressing need to optimize the inherent properties of aluminum for seamless integration into automotive manufacturing processes. This study, conducted at Trimet, Germany's largest aluminum producer, focuses on the batch homogenization process. The research employs the protocol of the biannual inspection procedures to assess monodirectional homogenization chambers rigorously. By comparing heating times using dummy blocks and thermocouples inserted in a dummy charge, the study ensures a time difference (∆t) of less than 60 minutes for optimal treatment quality and material properties, which agrees with the industry standard. The primary objective is to evaluate chamber responses to variations in billet layer separation, specifically exploring the precise height that maintains an optimal (∆t), when altered from the current height of 80 mm to 40 or 50 mm. The study identifies 50 mm as the optimal separation. Additionally, the research evaluates the material response to thermal gradients in monodirectional furnaces, focusing on two materials from the 6xxx series of aluminum alloys: EN AW-6010A and EN AW-6082. The fastest and slowest heating billets undergo pre- and post-homogenization microstructural and material property assessments. This comprehensive analysis encompasses chemical composition, visual inspections, grain size determination, hardness measurements, and analysis of alpha and beta phases. These insights contribute to understanding material quality variations based on positioning within the batch assembly of aluminum production billets, providing valuable data for refining manufacturing processes and ensuring consistent material excellence.