Present and further part constructions will be increasingly designed as hybrid material combinations. Due to the optimized local material adaption, the final part properties can reach maximized performance and efficiency. The increasing design implementation of multi-material structures leads to a rising demand for processes which join dissimilar materials (e.g. metal-polymer, thermoplastic-thermoset or incompatible thermoplastics) reliably. Concerning joining metal to polymer, the market offers various suitable joining techniques, which can be classified in adhesive bonding, welding-based techniques, mechanical fastening as well as hybrid joining technologies like injection over molding or combinations of the individual techniques above. Due to its cost-efficient processing, a high degree of automation as well as a typically low cycle time, clinching is one of the most commonly used joining processes, usually in the field of thin-sheet metal joining. Considering the clinching process, the existing research already shows that it is basically possible to join different polymers to aluminum and steel. The present study deals with an innovative process combination of clinching and hot-melt adhesive bonding of fiber-reinforced polyamide (PA6-GF15) to steel. The energy input for the hot-melt adhesive bonding is performed by torsional ultrasonic welding. By using this strategy, the achievable weld strength could be considerably increased. The study was aimed to analyze design variations of the weld seam to reach steady joint properties in spite of unsteady manufacturing conditions and to minimize interactions between clinching and ultrasonic welding. Furthermore, the study focusses on the form closure of the clinching joint and its time-dependent stability as a function of the material´s moisture content and forming temperature. The correlation between relaxation behavior and glass transition temperature of PA6-GF15 was investigated to minimize the loss of tightness.