Influence of the process parameter of resistance spot welding and the geometry of weldable load introducing elements for FRP/metal joints on the heat input
Sven Roth, Alisa Hezler, Oliver Pampus, Sven Coutandin, Jürgen Fleischer
Abstract
Resistance spot welding is one of the most economical joining processes when manufacturing conventional steel bodies in the automotive sector. However, its applicability in future body constructions is limited due to the growing material mix. Since the demands of efficiency and weight reduction are steadily increasing, modern car bodies implement lightweight materials, especially fibre-reinforced plastics (FRP), in a multi-material design. To enable the joining of FRP/steel constructions with resistance spot welding, weldable inserts can be embedded in the FRP. In order to evaluate the thermal damage to the surrounding polymer, an experimental study of the welding induced heat is presented in this study. The influence of welding parameter, metal sheet thickness and alloying degree on the heat input are characterised. Based on this data, weldability lobes and energy input diagrams are derived. Furthermore, the dependency between insert geometry and the resulting temperature distribution is examined.