Research On Friction Stir Welding Progress And Simulation Of 5052 And 6061 Aluminum Alloy

Friction stir welding(FSW) technology is one of the most potential method in a world of solid-phase welding. In the past few years, FSW has been widely used in many fields such as aviation, shipbuilding, nuclear industry and rail vehicles as it develops. In this paper, the FSW of the 5052 aluminium alloy sheets in 3mm thickness and 6061 aluminium alloy sheets in 4mm thickness had been studied.First, this paper studied the influence of the mixing head rotation speed and the welding speed on FSW joint performance when the plunge depth keeps as 0.3mm. The results indicates that the joints of 5052 aluminium alloy shows best performance when the mixing head rotation speed keeps as R=1000r/min and the welding speed keeps as v=100mm/min and the joints of 6061 aluminium alloy shows best performance when the mixing head rotation speed keeps as R=800r/min and the welding speed keeps as v=120mm/min.The highest tensile strength of both joints can reach the 90% of parent metal. The hardness in weld zone is lower than that in parent metal,and lowest in thermo-mechanically affected zone (TMAZ).Second, The influence of FSW process parameters on the distribution of residual stress of the two kinds of aluminum alloy had been studied. The results shows that distribution of residual stress is asymmetric in weld zone:The residual stress on the forward side is higher than the backward side; the longitudinal residual stress is higher than the transverse residual stress. Besides, The residual stress is relative to mixing head speed and welding speed.The faster the mixing head speed, the higher the residual stress; The faster the welding speed, the greater the residual stress.At last, Taking ANSYS Workbench as a tool, a reasonable heat source model had been established for the numerical simulation of FSW. The FSW process of 6061 aluminium alloy had been simulated, at the same time, the different welding speed and rotating speed on the temperature field and stress field distribution had been studied. The results are basically consistent with the experiment results. The simulation shows that the highest temperature of shaft shoulder affected reaches about 320℃, which is consistent with measured result. This fact had verified the correctness of the proposed heat source model. The highest temperature of weld zone reaches about 550 ℃. The temperature difference in thickness direction is not obvious;The maximum residual stress appears in weld seam center; The stress values is a little lower than measured values. The heat source model still needs to be further optimized.