KryoAlu - Cryogenic conditions make aluminum easier to form

Lightweight construction is a continuous trend in car body manufacturing. A lower car body weight reduces fuel consumption and harmful emissions or helps to compensate for the heavy battery packs in electric vehicles. Therefore the automotive industry and its suppliers are in constant search of innovative materials and novel production of processes for car body components.

Aluminum sheet alloys play an important role in modern lightweight car concepts. However, compared with steel, their formability at room temperature is low. Sheet forming processes at elevated temperatures have been investigated intensely in recent years, but no costefficient serial production could be realized up to the present date.

A significant improvement of the formability of aluminum sheets, however, can be achieved at cryogenic, i.e. very low temperatures. The novel cryogenic sheet forming process, which was studied in this project, might be an important step towards light, complex, highly integrated, single piece automotive parts which meet the harsh requirements of the future with regard to safety, cost-efficiency and environmental sustainability.

Freezing the production process

Within a co-operative research project, LKR together with scientific and industrial partners from Austria and Germany successfully set up a lab-scale process line for the cryogenic forming of high-strength aluminium alloys. Special measurement devices were constructed in order to determine the mechanical material properties at low temperatures down to -196°C.

In addition, lubricants for cryogenic conditions were systematically tested and an innovative refrigeration technique for the cooling of the forming tool was developed. With the help of numerical Finite-Element models, the forming tool with cooling channels of a complex-shape mini B-pillar was designed and manufactured.

The feasibility of cryogenic sheet forming was successfully demonstrated. Motivated by the present results the project partners aim at transferring the process to an industrial scale in a follow-up co-operation.

Consortium Manager

AIT Austrian Institute of Technology, LKR Leichtmetallkompetenzzentrum Ranshofen GmbH

Other Consortium Partners

• Aerospace & Advanced Composites GmbH
• AIT Austrian Institute of Technology GmbH
• Fill GmbH
• Linde Gas GmbH
• voestalpine Metal Forming GmbH
• voestalpine Polynorm GmbH & Co KG

Project Coordinator

Nikolay Sotirov
E-Mail: nikolay.sotirov@ait.ac.at