Numerical Simulation and Experimental Investigation of Friction Stir Rivet Welding Process for AA6061-T6

This article proposed a novel friction stir rivet welding process to join aluminum alloy 6061-T6 sheets in lap configuration with threaded rivet employed. The material flow behavior and temperature distribution of FSRW process are analysed using Simufact Forming 15.0 software, and joints have been obtained on the modified CNC machine with 1200rpm rotational speed and 10s dwell time. Rotational speed and dwell time are important factors which affecting mechanical properties of FSRWed joints. The welding heat input is determined by the rotation speed, while the heat time of plasticized materials is controlled by dwell time during FSRW process. In order to obtain FSRWed joints with excellent mechanical properties, welding heat input is taken as measurement standard, and the reasonable range of rotational speed and dwell time have been investigated by numerical simulation and statistics. The macroscopic morphology of 3 mm and 4 mm thick aluminum alloy 6061-T6 FSRWed joint we obtained shares uniform characteristic with the numerical simulation forming appearance whose upper surface tests smooth but exists “flash”, and stir zone, heat affected zone, thermo-mechanically affected zone and base metal four distinct zones can be observed in transverse section. The results of numerical simulation and experimental study show that the potential process we proposed takes advantages of solid-state welding and riveting technology. Not only metallurgical bonding can be obtained between upper and lower sheets, but also mechanical properties will be strengthened by riveting.