Atlas Copco develops joining technique for high strength aluminium in automotive applications

Atlas Copco has developed a fully hollow self-pierce rivet called the Henrob T-rivet in order to join   up to four layers of high-strength, low-deformability 6,000 series aluminium alloys.

According to Atlas Copco IAS, the T-rivets are suitable for the automotive industry in mechanical joining processes for new lightweight constructions and multi-material design. Aluminium alloys put up a challenge for the joining process due to its low ductility (formability). As more and more aluminium is being used in body-in-white applications, new joining techniques have become a must for better performance of aluminium alloys.

The new joining element has a completely tubular structure and is better suitable for joining several layers of high-strength aluminium. This in turn avoids cracks in the lowest material layer because the brittle aluminium is not deformed that much in the joining process. The tip of the T-rivet, according to the manufacturer also improves the process by allowing more uniform penetration of the material. A special coating is used to reduce friction and facilitate the flow of aluminium into the cavity to safely join thick layers. In this way, even thick layers can be joined reliably and safely.

6,000 aluminium alloys are often used for the construction of impact surfaces, such as the A and B pillars and other safety-critical applications in car body construction. According to Atlas Copco a permanently strong, multi-layer joint is particularly important in these applications.