Simulation of AA 6070 Recrystallization in TIG Welding

Aluminum alloys have many applications in transportation industry because of their abundance, ease of production, and appropriate mechanical and physical properties. One of these alloys is obtained by combining aluminum with silicon and magnesium (Al-Mg-Si alloys). Since the plates of this alloy are rolled up, heat transfer and crystallization in the heat-affected zone is an important point in their welding. In this study, we have attempted to investigate welding-induced recrystallization in this alloy using the finite element method. For this purpose, the physics of the problem was defined and simulated using the ANSYS software. In the next step, the results of theoretical (simulated) and experimental investigations were compared and the effect of current on the size of weld pool and thermal cycle of different samples was assessed. Then, through microscopic examination of different areas of the welded samples, the size of recrystallized area was measured and compared with the results of mathematical calculations. Finally, the hardness of the weld zone and recrystallized area was analyzed. A temperature of 630°C and a holding time of about 0.3 s will be sufficient for recrystallization of this alloy during welding.