The practical development of this master's thesis took place in the months of October and November 2023. Welding processes were carried out using equipment from “stirtec,” installed at the EuroDies Italia Srl’workshop located in Rivoli (TO). All laboratory tests were conducted at the J-Tech laboratory located at the main campus of the Polytechnic University of Turin. The thesis focuses on the application of the passive repair process for filler friction on AISI 304 alloy. The joining process used is Friction Stir Welding (FSW), which offers significant advantages in terms of joint strength and quality. The main material used for the experiments is AISI 304 steel, known for its strength and ductility.