Honda Motor Co. Ltd. has developed a new technology that joins steel and aluminium. Honda has applied the newly developed technology to mass production vehicles, initially to the North American version of the all-new Acura RLX. The Japanese carmaker will expand the application of the technology other models.
The initial application of the new technology was with a new aluminium outer door panel -- conventionally made of steel -- joined to a steel inner door panel. To join together steel and aluminium, which are considered dissimilar metals, there is a need to simultaneously establish several different technologies, including those that prevent electrical corrosion and thermal deformation, which are usually caused by the different expansion rates of steel and aluminium.
Honda developed three new technologies that allowed adoption of aluminium for the outer door panel. One of the developed technologies is for joining dissimilar materials -- the adoption of ‘3D Lock Seam’ (3DLS) structure, in which the steel panel and aluminium panel are layered and hemmed together twice.
Another technology developed is for preventing electrical corrosion -- the adoption of highly anticorrosive steel for the inner panel as well as the adoption of a new form that assures the complete filling of the gap with adhesive agent.
The third technology developed is for controlling thermal deformation -- adoption of an adhesive agent with low elastic modulus and optimized position of the 3D Lock Seam. The new technologies bear several advantages like the elimination of a spot welding process required to join conventional steel door panels. The new technologies also do not require a dedicated process, thereby allowing existing production lines to accommodate them.