Joining, which is an essential technology of many of our products, has a very long tradition at the IWS. In addition to the work on conventional arc welding processes, our team also investigates different variations of friction welding and resistance spot welding. Not only existing modern techniques are studied in detail in these topics, but prototypes are also created to find innovative solutions and to further develop experimental techniques. Steel still represents the main area of researched materials, but other different materials (plastics, aluminum) are also examined. In the future both the demand for the joining of different materials and hence the need for research and development in this field will be increased. Modeling and simulation techniques are being used as an invaluable part of the joining technology in order to better interpret the experimental results and to deepen our understanding of the process.