The Institut für Integrierte Produktion Hannover (IPH) gGmbH and Institute of Welding and Machining (ISAF) at Clausthal University of Technology want to form and join steel sheets and aluminum bulk parts in one process step during the production process. In the past, the individual parts have first been formed and then joined in a second step, mostly using stud welding. Consolidating these two steps into one – in a process called hybrid compound forging – eliminates one process step, which, in turn, accelerates production and cuts costs.
There are, though, two challenges that need to be overcome. First, steel and aluminum have different melting points; second, directly joining the two materials results in brittle intermetallic phases, which makes the end product unsuitable for practical use. The scientists have therefore used zinc-plated steel sheets and aluminum studs to firmly bond the two parts. Because zinc firmly bonds to aluminum as well as to steel without creating brittle transition layers.
It should in future be possible to apply the new hybrid compound forging process for lightweight components in the automotive and aviation industries. The process is currently still in the prototype phase.