Forces and temperature variation during friction stir welding of aluminum alloy AA6082-T6

The variation of forces, torque, absorbed energy, and temperature distribution during friction stir welding process is investigated. Friction stir welding experiments were performed on an aluminum Al-Si-Mg alloy varying the tool rotation speed and the welding speed. An instrumented milling machine equipped with 3-axis load cell was adopted to measure the forces during the process. Temperature measurements were performed by means of an IR camera. A significant increase in temperature was observed during the process due to a “process preheating effect.” This resulted in the variation of the main forces. Phenomenological models were developed to describe these trends. The results indicated that processing conditions involving higher energy produced higher variation of temperature during the process, up to 2.3 °C mm−1.