Abstract
In the continuous struggle to improve car body properties, and at the same time reduce the weight of the structure, new grades of high- and extra high strength steels, applied to new car body concepts, are being evaluated. This paper will contain the following topics:
New structural solutions, which indicate the potential in parts reduction through space-frame technology and tailored welded blank techniques. These concepts are based on an increased number of components with closed cross sections, manufactured out of high-strength steels and using production methods like roll forming, hydro forming and hot forming. The utilization of these steel grades and manufacturing techniques indicates a strong improvement in terms of strength properties and energy absorption capacity in relation to component weight and cost.
Formability results from trials on high strength DP and TRIP grades ranging from basic FLD-, LDH- and spring-back investigations to semi-industrial tests on real body parts.
New ideas about joint designs, assembly sequences and the use of various joining methods such as resistance spot welding, laser welding, GMAW and adhesive bonding
At the end follows a discussion on weight/cost efficiency of different body concepts put in relation to high and low volume production aspects. Recommendations and guidelines are given about the selection of material grade and joining method in regard to desired product properties and production requirements. Furthermore it outlines the future for other lightweight solutions including high strength stainless steel applications and mix/materials scenarios built on modules consisting of both aluminium and high strength steel materials.