Advances in welding and joining processes of multi-material lightweight car body

Abstract

Vehicle lightweighting, as an important means for energy saving and emission reduction, has drawn great attention from all over the world. Considering cost, performance and effect of the lightweighting, a mixed use of different materials, e.g. multi-material design, has become the most significant method of vehicle body lightweighting in the future. However, due to the large difference in physical properties of dissimilar materials, traditional resistance spot welding process can hardly be used to obtain reliable joints, which is posing new challenges to the assembly of multi-material vehicle body. Through comparing and analyzing the differences in physical properties of typical dissimilar materials, three major scientific problems that must be faced and solved for the welding and joining of dissimilar materials are proposed, i.e., hard and brittle phases at faying surface, galvanic corrosion and distortion and stress. The research progress, advantages, disadvantages, application status and development trends of four kinds of dissimilar material joining processes, i.e., mechanical joining, welding-brazing, solid-state welding and adhesive bonding were analyzed and evaluated, aiming at providing useful references to the design and manufacturing of lightweight vehicle bodies.