Latest developments in sheet metal forming technologies and materials for automotive application: the use of ultra high strength steels at Fiat to reach weight reduction at sustainable costs

In new vehicles development weight reduction is one of the most important driving force often conflicting with other missions which would require additional mass (crashworthiness, comfort, etc). The use of HSS, especially new grades with very high strength and good fomability is the most competitive way to reduce weight. Nevertheless some limitations come from manufacturing HSS: springback, residual stresses, weldability should be taken into account in product development in order to avoid an expensive set LIP phase in the press shop and in the body shop. This paper focus on the recent experience achieved by Fiat in introducing HSS up to reach a share higher than 60% in weight applying and developing new methodologies to solve in the design phase any criticality arising from the use of this material.