P 890 - Forming properties of laser-welded tailor-welded blanks made of high-strength multiphase steels - Characterisation, modelling and verification

P 883 - Fixing of bonded mixed construction joints made of aluminium in combination with press-hardened 22MnB5 using a new riveting system Solid self-pierce riveting in combination with adhesive bonding technology is a hybrid joining technique that has a high application potential compared to a large number of alternative joining technologies, particularly with regard to the joining of high-strength materials in mixed construction. With the aim of qualifying this process for joining semi-finished thin sheet metal products made of ultra-high-strength steel with a tensile strength of around 1600 MPa in mixed joints with wrought aluminium alloys for practical application, investigations into elementary bonding and full-punch riveting as well as the combined application of these joining techniques were carried out as part of this research project. The central object of the investigations is to change the functional principle of the self-pierce riveting tools and auxiliary joining elements from the existing interactions in such a way that critical joining part deformations can be avoided and an optimised adhesive bond can be achieved. A one-piece die concept is retained, which is optimised by an adapted basic shape. The use of a support ring around the mould in combination with a flat head rivet shows a significant improvement in the joint quality. The use of two different adhesives demonstrated the robustness of the modified process variant. The performance of the optimisations achieved is also demonstrated by investigations into the load-bearing behaviour of elementary and hybrid joints under static and dynamic force application. For example, it was possible to more than double the load-bearing capacity of the joint between 22MnB5 in 1.5 mm and AA6014 in 1.15 mm compared to the conventionally joined composite. This means that the strength potential offered by the aluminium material is almost fully exploited. Finally, recommendations for the design and production handling of the process are derived from the knowledge gained. The IGF project 16789 N of the Forschungsvereinigung Stahlanwendung e.V. FOSTA, Düsseldorf, was funded via the AiF within the framework of the programme for the promotion of joint industrial research (IGF) by the Federal Ministry for Economic Affairs and Energy on the basis of a resolution of the German Bundestag. The research project was carried out at the Laboratory for Materials and Joining Technology at Paderborn University. Authors: O. Hahn, G. Meschut, M. Matzke Publication: 2015