Evaluation of Modular Roll-Setup to Roll Grooves into Steel Sheets

Abstract

Hybrid structures made of aluminium and steel are used in an increasing amount to produce lightweight optimised parts, e.g. for the automotive industry. One option to produce these optimised components is a combination of a steel sheet with a reinforcing aluminium rib structure by high pressure die casting. Achieving a reliable junction between the different materials during the short casting time is a major challenge in creating these hybrid components. Improving this junction is the topic of an ongoing research study in which a form closure connection is enabled by structuring the steel surface prior to the casting process. In order to meet the demands of the later application, the surface structure has to ensure the filling during the casting as well as a stable form closure connection. Thus, deep groove structures with a perpendicular wall angel straight to the casting direction were identified, since a deeper structure increases the clamping area and a perpendicular wall angle improves the form closure connection. However, the production of this structure in a large scale and a short time becomes difficult using conventional structuring processes. In this work the capability of an adapted rolling process which consists of stacked discs with varying thickness and diameter was studied in order to manufacture these grooves. Several experiments were performed to determine the influence of the height reduction and rolling force on the resulting structure. First results obtained with the presented experiments show the good predictability of the resulting size of the structure depending on the thickness reduction and the rolling force normalised to one millimetre structured width.