The key is a new “3D Lock Seam” structure, where the steel and aluminum pieces are layered and hemmed together twice, preventing them from detaching.
In addition, the welding technique relies on the use of a special adhesive agent that assures the complete filling of any gap between the two pieces, helping to prevent corrosion.
Acura has already started using the technique, with the doors of its latest 2014 RLX featuring aluminum outer panels welded to steel innards.
The benefits of the increased use of aluminum in vehicle construction (over steel) are obvious. By using more of the lightweight stuff, Acura is able to improve the fuel economy and dynamics of its vehicles.
Taking the RLX as an example, the switch to aluminum outer panels for the doors has helped save weight of around 17 percent per door compared to a conventional all-steel design. In addition, weight reduction at the outer side of the vehicle body concentrates the point of gravity closer towards the center of the vehicle, contributing to improved stability.
From a production standpoint, the advantages of these new technologies include elimination of a spot welding process required to join conventional steel door panels. Moreover, these technologies do not require a dedicated process; as a result, existing production lines can accommodate it.
The automaker will eventually expand the technology to other models, including those from mainstream brand Honda.
The latest announcement follows a similar one from General Motors, which last September said it had developed an industry-first welding technique for aluminum to aluminum components.