Honda reveals new technology for joining steel and aluminum

Japan’s Honda Motor Corp. revealed on Monday that it has developed a new technology that will allow steel and aluminum to be joined together, and thus used in new applications in car manufacturing. One of the first places the technology will be put to use is in using aluminum for a car’s outer door panel, which has usually been made of steel, starting with the 2013 Acura RLX model to go on sale in the U.S. in March.

Honda explains that several different technologies had to be developed in order to address the problems in joining two dissimilar metals, such as preventing corrosion, as well as thermal deformation caused by steel and aluminum’s different expansion rates. Three of the identified technological developments that have allowed the use of aluminum in the outer door panel are the joining the of two metals with a “3D Lock Seam,” where two panels are layered and hemmed together twice; the use of a highly anticorrosive steel for the inner layer in combination with a form that completely fills any gaps with adhesive agent; and the use of an adhesive agent that is optimized for the 3D Lock Seam.

The car manufacturer says this new joining process eliminates the need for spot welding, and as it doesn’t require a dedicated process, it can be added to existing production lines. In terms of advantages for the car, the use of aluminum reduces the door panel’s weight by 17%, part of an effort to reduce vehicle weight overall in order to gas mileage. Honda also points out that reducing the weight of a car body’s outer side improves having the center of the vehicle serve as the concentrated point of gravity, something that improves overall stability. Following the Acura RLX, Honda plans to apply the metal-joining technology to other models in its lineup.