Alcoa unveils new aluminum joining breakthrough

Alcoa has developed a new method for joining aluminum to a wide range of other materials, including steels, magnesium and composites. Alcoa is one of the largest aluminum producers in the world and has a vested interest in lowering barriers to use in aluminum in the automotive sector.

The new method is a breakthrough in resistance spot riveting called the RSR joining system. According to a statement from Alcoa, RSR technology can join dissimilar materials using the same equipment as conventional spot welds but offers automakers the flexibility to switch between it and conventional welds, depending on the material.

The new system was developed with OEMs in mind, but it could eventually make its way to the shop floor.

“Our RSR technology is going to be a powerful tool in the array of joining options for the automotive industry,” said Ray Kilmer, Alcoa’s Chief Technology Officer and Executive Vice President. “As automakers continue to design vehicles using multi-material combinations, RSR technology is the ideal joining solution. It can easily accommodate stack up changes on the assembly line and it leverages existing welding robots outfitted with our automatic feeding systems.”

Alcoa is working with Honda R & D Americas and Ohio State University  to demonstrate the use of RSR joining on a prototype scale. The work is being funded in part through a grant from the US Department of Energy.

Ultimately, the goal is to enable multi-material automotive body structures that achieve an additional 10 to 20 percent weight reduction over those made from conventional high strength steel.

"We are working with Alcoa on advanced alloys and the RSR joining technology in conjunction with the Department of Energy because we are optimistic about the new value these advanced technologies will enable us to deliver to our customers in terms of performance and fuel efficiency," said Eric Boettcher, Technical Leader, Advanced Body Design of Honda.

According to a statement from Alcoa, RSR technology can join a variety of dissimilar materials, including conventional aluminum, high-strength aluminum, steel, high-strength steel, ultra-high strength steel, magnesium and composites. 

The RSR joining methods can be used in many places throughout the vehicles, including frames, floors, closeout panels, pillars, roofs, seats and intrusion beams.

Multi-material construction is growing, and anything that allows the OEMs to further reduce weight will be of strong interest. Perhaps most enticing for manufacturers, automakers only need to make minimal modifications to exisitng production lines to start using Alcoa's RSR technology. A statement from Alcoa says conventional spot welding equipment and robotic automation can be adapted for use with RSR technology, which can easily shift between material combinations and fastener types.

For more information, please visit Alcoa's Resistance Spot Riveting page. You can see the process in action in the video below.