New aluminium solutions for car body design with an optimized weight reduction/cost balance

摘要

Constellium's recent automotive body sheet innovations support weight and process cost reductions. The classical lever to reduce the gauge is to increase the strength. New generation 6xxx and 7xxx-series alloys increase the strength available to design body structures by a factor two. More original is a solution dedicated to stiffness-sized parts, with an increase of the elastic modulus/density ratio by 15%. These weight reduction options are complemented by solutions reducing the process cost, in particular a remote-laser weldable alloy. This alloy can be welded without filler wire within a very low welding cycle time. The ALLEGRIA project, supported by PSA, Renault, SNOP and Constellium has focused on the implementation of one of these solutions, high strength 7xxx, in particular the forming hurdle.