Innovative roll joining technology for a new kind of special section

A revolution is currently taking place at Hoesch Hohenlimburg GmbH in the manufacture of special sections. The company is collaborating with the materials and joining technology laboratory of Paderborn University and Dr. Lappe & Niemeier-Profiltechnik GmbH to develop the DAVEX® process to commercial maturity. The process allows the manufacture of sections in which widely differing materials are combined into a single component. DAVEX® sections can be made from previously unproducible combinations of carbon steel and aluminum, stainless steel and plastic or coated steel and aluminum.

In contrast with roll forming, DAVEX® is a roll joining process which joins strips in a T joint. First a groove is rolled into the flange material to accommodate the web. A contour is then worked into the strip used as the web, which is inserted in the groove. Finally, the actual joining process is performed in which a so-called locking groove is rolled into each side of the web/flange connection, thus providing a friction-locking joint. At the same time material flows into the contour of the web and also provides a form-locking connection.

The result is an optimal, heavy-duty connection. Cross-sectional losses in the flange caused by the groove are compensated by the work hardening of the material in the groove area. The contour in the web can be shaped for specific loading such as cross tension and shearing. The DAVEX® process not only overcomes the limits of roll forming, it also offers more possibilities than welding, riveting or adhesive bonding. DAVEX® is suitable for all semis based on T-joints. Hoesch Hohenlimburg GmbH will start up the production line in the coming year.

The potential offered by the roll joining process to combine different materials in a section opens up new perspectives for numerous branches of industry. For example, extremely light but nonetheless very strong sections of steel and aluminum or plastic can be used in automotive construction as intrusion beams, bumper bars or side members. In shipbuilding DAVEX® will make it possible to manufacture light, stable panels for bulkheads and decks. In the construction sector, steel/plastic combinations can be used for facades and windows. And sections of this kind can also be used in all applications where thermal or noise separation is required.

Extensive trials have proved the suitability of DAVEX® sections for practical applications. Fatigue, flexural, torsional and crash tests have shown that the rolled joints can withstand extreme loads. Despite their hybrid composition, DAVEX® sections are nonetheless recyclable. Mechanically breaking the roll joint provides grade-sorted materials suitable for re-use.

For further reference: ThyssenKrupp AG, Trade Press, Bernd Overmaat
Tel: +49-211-824-36012, Fax: +49-211-824-36035
e-mail: overmaat@tk.thyssenkrupp.com